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CONTENTS
ViewpointSummer Takes Place at the Beach Now . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Industry News
Ansoft Seminars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Traction Refurbishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Fairchild and Changhong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Electric Scooters from Automotive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Renesas joins AUTOSAR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Zetex Achieves Automotive Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Tektronix Oscilloscopes for Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Cover Story
Smart Power Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Trends in Distributed Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Features
Technology Review—IGBT’s and Modules are Good for Vehicles . . . . . . . . . . . . . . . . . . 9
Magnetics—Robust Control of an Electromagnetic Actuator . . . . . . . . . . . . . . . . . . . . . .18
Marketwatch—Power-Management Semiconductor Market Forecast . . . . . . . . . . . . . . .22
Automotive Electronics: Part IITrench MOSFETs Feature Rugged, Efficient switching . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Increasing Passenger Car Comfort and Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Design Options for Automotive Motor Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Off-Board Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Lighting up Automotive Instrument Panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
New Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49-52
Member Representing
Eric Carroll ABB SwitzerlandBob Christy Allegro MicroSystemsPaul Löser Analog DevicesArnold Alderman AnagenesisDr. Uwe Knorr Ansoft Todd Hendrix Artesyn TechnologiesHeinz Rüedi CT-Concept TechnologyDr. Reinhold Bayerer eupecChris Rexer Fairchild SemiconductorDr. Leo Lorenz Infineon Technologies
Power Systems Design Europe Steering Committee Members
PowerSystems DesignE U R O P EPowerSystems DesignE U R O P E
Member Representing
Eric Lidow International RectifierDavid Bell Linear TechnologyRüdiger Bürkel LEM ComponentsPaul Greenland National SemiconductorKirk Schwiebert OhmiteChristophe Basso On SemiconductorDr. Thomas Stockmeier SemikronDr. Martin Schlecht SynQorUwe Mengelkamp Texas InstrumentsPeter Sontheimer Tyco Electronics
2 Power Systems Design Europe September 2004
Europeans received a late good stable weath-er condition that pushes everybody to the beach.
I am watching the young children buildingtheir sandcastles while the tide runs all aroundthem, perhaps some of the kids will be the nextgeneration of engineers. Having wireless LANmay let me work with my laptop direct on thebeach. The weather today with wind and watersurrounded by nice sunshine in the northernregion is like heaven. I am overlooking the Kielfjord and the beach is only a few steps away withthe continuous changing nature of the Balticwaterfront. Europeans have much more inter-esting views at the beach than our friends inthe US. The freedom of “less”, “top” or “bottom”or both.
I remember a gentleman I had worked with ona module program who was the packagingdirector of a US company made a lasting noseimpression on the glass at my favorite fishrestaurant amazed at the beach scenery. Thiskind of freedom is only known in Europe.
In this issue, we continue with Part II of ourseries on Automotive electronics. Part I whichappeared in the July/August issue proved to bePower Systems Design Europe’s strongestissue editorially and in ad pages since we start-ed the magazine in January, our thanks to theindustry for such strong support and confidencein our efforts.
Electronics gives the life and functionality tomodern cars. Economic aspects are seen inthe spot of rising energy cost. Mainly the fuelprice is going up and the mileage is critical. WeEuropeans say liter per kilometer if we are noton the tunneled island called United Kingdom.
Modern electronics using power switchesmakes drive by wire possible. That means steer-ing can be put anywhere in the car. Left or rightside for the driver and his steering wheel oreven on the back seats if it makes sense.
That amount of freedom in electronics allowsus the freedom in our designs. Hybrid solutionsincluding fuel cell designs in automotive will bepushed by the legislative. The upcoming restric-tions will force us to innovation that helps us tocontinue with individual transportation. Masstransportation will be good for long distanceand in big cities. For all the rest we need free-dom and our own automobile.
Automotive electronics serves a wide field inmodern vehicles. Electronics allows the inno-vation to more efficient cars for the future.Whether we talk about combustion, electric orhybrid cars. The electronic components makesit happen, that our designs become reality.
Fall is coming along with “Electronica”, PowerSystems Design Europe’s October issue will bedistributed to that all important show in Munich.I have been invited to serve as moderator atthe podium discussions on power electronics. Asengineers we continue to learn all our life. It isa never ending process in our profession that dif-ferentiates us from other jobs and professions.
Stop by and see me on the show floor!
Best regards
Bodo [email protected]
Summer Takes Placeat the Beach Now
VIEWPOINT
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Volume 1, Issue 7
www.powersystemsdesign.com4 5Power Systems Design Europe September 2004
INDUSTRY NEWS
The GSEM '04: 2004 Global Seminars -Electromechanical Series offers a realisticreport on the state of the art in electromechan-ical design and simulation and presents solu-tions that address the future demands of elec-trical, transportation and power electronicsand drives industries. Attendees will learn howindustry experts use simulation to more effi-ciently design today’s advanced electro-mechanical features, such as electric-assist
power steering, electric pumps, fans, electro-mechanical actuators and power-processingelements. For details, go to:www.ansoft.com/gsem04.
Ansoft is a leading developer of high-per-formance electronic design automation (EDA)software. Engineers use Ansoft software todesign state-of-the-art products, such aselectromechanical components and systems,hybrid-electric vehicles, drive-by-wire systems,
power electronics, wireless products, integratedcircuits (ICs) and printed circuit boards (PCBs).
Interested parties may submit a 100-wordabstract for presentation by [email protected]
Asia and Europe during October andNovember2004. Please visit:www.ansoft.com/gsem04 for details.
Ansoft Seminars
Traction Refurbishment Westcode Semiconductors an IXYS com-
pany is awarded a development contract toupgrade the traction package of the Class 8Elocomotives by Spoornet (RSA railways). Theproposed design uses Westcode’s state ofthe art press-pack IGBT technology toreplace the fast thyristor based converters.
The contract is for the design, develop-ment and realisation of an upgrade packagefor the DC propulsion chopper system. Thisincludes replacing existing obsolete reverseconducting thyristor technology with
Westcode’s state of the art press-packIGBT’s, gate drivers and associated powerelectronics. The upgrade package will retrofitinto the existing power cubicle and interface
directly to the existing controls and coolingsystem with the minimum of modifications.The system operates directly from the 3kVDCcatenery and will facilitate an increase of loadpower from 750kW to 1MW. There are cur-rently 99 of the Siemens BBC built locos inservice requiring this upgrade.
Contact us at [email protected] orby telephone: +44 (0)1249 444525
Fairchild and Changhong Fairchild announced the opening of a joint
product development laboratory with SichuanChanghong Electric Co., Ltd.—one of thelargest manufacturers of consumer devices in China. The lab enables the companies tocollaborate on product development usingFairchild’s leading edge power components.Fairchild’s power devices are designed into a broad range of Changhong products including color TVs, LCD TVs, PDP TVs,rear projection TVs, DVDs, set-top boxesand air conditioners.
Fairchild and Changhong have established
a close relationship over several years. Thisannouncement is an extension of that coop-eration. Changhong is known for technicalinnovation, quality products and significantproduction capabilities. Fairchild productsdesigned into Changhong consumer devicesinclude Green Mode Fairchild power switch-es, advanced power MOSFETs, interfaceswitches, diodes, logic devices and rectifiers.
Fairchild's components manage, distribute,convert and minimize power in a broad rangeof end markets including computing and dis-play, industrial, consumer, communications
and automotive segments. New power prod-ucts are gaining strong acceptance with cus-tomers, including Smart Power Modules forelectric motors, air conditioners and inductiveheating; Green Mode power switches for bat-tery chargers, televisions, display and PCs;MOSFETs for notebooks, displays and plas-ma panels; IGBTs for ignition control andinduction heating; and power supply con-trollers for microprocessors.
www.ansoft.com
www.westcode.de
www.fairchildsemi.de
Electric Scooters from VectrixThe Parker Automation servo motor-based
prototypes are now being road tested inEuropean cities.
Leveraging the efficiency of real-time, high-performance control, Vectrix Corporation hasselected the TMS320LF2401A digital signalcontroller from Texas Instruments for its revo-lutionary electric motor scooters. By pairingTI’s leading digital signal processing (DSP)-based motor control technology with a highperformance, custom designed brushlessservo motor from Parker SBC, part of the
Parker Automation division, the new light-weight Vectrix scooter delivers a level of per-formance and acceleration typically only foundin a 250-cc gasoline-powered motorcycle.Vectrix's scooter achieves this gas-like per-formance without the polluting emissions typi-cally found in two stroke gas engines. (Formore information on the LF2401A digital sig-nal controller, please visit www.ti.com/vectrixpr)
The LF2401A controller is ideal for applica-tions that require the high-performance of TI’sleading DSP technology along with the
peripheral integration and ease-of-use typi-cally found in a microcontroller (MCU). TI’sDSP-based controller helps Vectrix’s scootermotor operate more efficiently and at a higherlevel of performance than traditional MCUs oranalog designs. This increased functionalityand efficiency gives Vectrix a valuable edgein developing lightweight, inexpensive solu-tions for electrically powered transportationthat rival gas-powered options and are envi-ronmentally friendly.
www.ti.com
www.powersystemsdesign.com 76 Power Systems Design Europe September 2004
Zetex has achieved corporate registrationas an ISO/TS16949:2002 certified company,following audits conducted by UnderwritersLaboratories Inc. Jointly developed byInternational Automotive Task Force (IATF)members and the International StandardsOrganisation (ISO), ISO/TS16949:2002 isrecognised as the most comprehensive qualitymanagement standard for companies operat-ing in the automotive industry supply chain.
The quality registration strengthens Zetex’
position as a leading supplier of discrete andintegrated analog semiconductor devices toautomotive system integrators and vehiclemanufacturers alike. A broad range of Zetexpower management products includingIntelliFET smart MOSFETs, current monitorsand fan controller ICs are employed in a widevariety of automotive applications.
According to WSTS/Bosch, the globalsemiconductor demand in the automotivemanufacturing sector is expected to rise from
$13.7B in 2003 to $23.2B in 2008, represent-ing a compound annual growth rate of 11.1%.The research also indicates the growingimportance of semiconductors to the sector.As a percentage of the production cost of anaverage light vehicle, the semiconductor con-tent is forecast to grow from 9.5% in 2004 toover 15% in 2010.
Zetex achieves Automotive Standard
INDUSTRY NEWS
Power Events
• H2Expo 2004, September 15-17, Hamburg,
www.h2exp0.de
• Semi Expo 2004CIS, September 27- 30,
Moscow, http://wps2a.semi.org
• Automotive EMC 2004, October12, York
Racecourse UK, www.AutoEMC.net
• Power Conversion Design, October12-15,
Portsmouth UK, www.ejbloom.com
• Ansoft Seminar, October 21,Stuttgart/
Sindelfingen, http://www.ansoft.com/gsem04/
• Electronica 2004, November 9-12, Munich,
www.global-electronics.net
• Surface Mount 2004, November 16-18,
Brighton UK, www.smartgroup.org
• SPS/IPC/DRIVES 2004, November 23-25,
Nuremberg, www.mesago.de
• Embedded World 2005, February 22-24,
Nuremberg, www.embedded-world.de
Synchronous Buck Converter Family▼
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Linear Technology’s family of monolithic synchronous step-down converters provides conversion efficiencies up to 96% inlow profile footprints as small as 35mm2. Compared to linear regulators, switching converters offer superior power conver-sion efficiency when generating 1.xV from a single-cell Li-Ion battery. With LDOs, the associated power loss generates heatwhich equates to a reduction in battery run time. Also, our growing family of buck-boost converters provides the most effi-cient solution for generating 3.3V from this battery source. Isn’t it time you made the switch?
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Tektronix announced that Turkey’s firstfoundation university, Bilkent University, hasinstalled more than 100 Tektronix oscillo-scopes into a new laboratory to providemeasurement tools for undergraduate studentcoursework. The Electrical & ElectronicsEngineering Department of Bilkent University,Ankara, Turkey, attracts a significant portionof the highest performing students in Turkey.The 50-seat modern laboratory was designedto allow students to conduct analogue, digitaldesign, circuit, microprocessor and controlexperiments. The philosophy employed when
designing and setting up the laboratory wasto equip each bench with a computer thatcontrols the oscilloscope and a function/sig-nal generator using leading third-party soft-ware. This enables students to learn andemploy the concepts of modern experimenta-tion easily and effectively. Internet connec-tions to each bench are also provided, whichallows students to prepare and submit labreports via the network and to use Internetresources while they are in the lab. Theframework requires digital storage oscillo-scopes that have a computer and printerinterface, FFT math and high sampling rate.
Tektronix Oscilloscopes for Education
www.tektronix.com
www.zetex.com
Renesas joins AUTOSARRenesas announced that it has joined
AUTOSAR (Automotive Open SystemArchitecture), an industry partnership workingto establish standards for software interfacesand software modules for automobile elec-tronic control systems. Renesas Technologyjoined as a Premium Member.
In recent years electronic systems havecome to be used ever more extensively inautomobiles, a trend that is accelerating rap-
idly. Such systems are used for applicationsincluding engine control, body control, safetycontrol and information systems. As thisprocess has advanced, the share of the soft-ware component in the overall developmentprocess for automotive control systems hasgrown substantially. The need is growing forsoftware standardisation as a means toimprove the efficiency of the developmentprocess, and thereby enable even more
extensive use of electronic systems in future.Such standardisation would allow previouslydeveloped software to be used in new prod-ucts as well as in microcomputers and micro-processors from different manufacturers.
AUTOSAR was established in July 2003 to promote the standardisation of software forthe automobile industry.
www.renesas.com
Europe Sales Offices: France 33-1-41079555 Italy 39-02-38093656 Germany 49-89-9624550 Sweden 46-8-623-1600United Kingdom 44-1628-477066 Finland 358-9-88733699Distributors: Australia Soanar 61-2-9741-0122 Belgium ACAL 32-0-2-7205983 Finland Tech Data 358-9-88733382 FranceArrow Electronique 33-1-49-784978
Tekelec Airtronic 33-1-56302425 Germany Insight 49-89-611080,Setron 49-531-80980 Ireland MEMEC 353-61-411842 IsraelAvnet Components 972-9-778-0351 Italy Silverstar 39-02-66125-1Netherlands ACAL 31-0-402502602 Spain Arrow 34-91-304-3040Turkey Arrow Elektronik 90-216-4645090 (Ext. 238) UK ArrowElectronics 44-1234-791719, Insight Memec 44-1296-330061
www.powersystemsdesign.com8 9Power Systems Design Europe September 2004
TECHNOLOGY REVIEW
Continued improvement in packaging and mounting technology allows for more efficient
performance in electric automotive motor drives.
Bodo Arlt, Power Systems Design Europe
Editor-in-Chief
IGBTs are dominating all areas in avoltage range from 200V up to 6500V.The IGBT with it’s high current density
is the perfect candidate allowing to builda high current switch in a small packageat a reasonable price. The IGBT is aMOS gate controlled power switch. Cellstructure and manufacturing process arevery similar to a MOSFET. The IGBT isthe workhorse of modern inverter tech-nology. It is the preferred switch becauseof short circuit capability, speed andimproved saturation voltage.
The drive control using IGBTs technol-ogy permits sensitive starting, powerfulacceleration and finely regulated electricmotor braking with energy reclamation.In automotive applications, the demandon the cars’ electrical power generationis increasing due to the requirement formore driving comfort, better perform-ance and more features. This while thefuel consumption and emissions mustbe decreased. Auto makers likeMercedes with its luxury S class haveannounced to have a hybrid version togain mileage. The Japanese Toyota withthe Lexus Automobiles are pushing themarket. Electrical—and Hybrid Electrical—Vehicles are using already IGBT mod-ules. Their bus voltage is between200VDC and 400VDC with DC currentsup to a few hundred amps.
Synchronous or asynchronousmachines are used for automotive appli-cations powered by frequency converters.Power modules with a high switching
power density combined with low lossdesigns. To achieve these tasks weneed integrated insulation to the heat-sink, low thermal resistance and lowstray inductance. The power semicon-ductors, along with the energy storagedevice, are the two main components,which determine the functionality,reliability, and cost. To compliment theIGBT performance, modules have toinclude perfect diodes with soft recovery characteristics.
Both IGBT concepts of Punch Through(PT) and Non Punch Through (NPT)have been improved over the years.Reducing the wafer thickness in theNPT side also the transistor cell struc-tures changed to minimised planar cellsor trench cells. Outstanding improvementin the IGBT development has beenachieved with the Field Stop IGBT.
Pressure contacts have been suc-cessful introduced into modules by ABBand Semikron. These modules aredesigned to take a PCB containing con-trol and gate drive, which snaps on tothe module, and is held in place byrugged hooks. A product resulting out ofthis area is the SKAI, an optimized sys-tem for hybrid and electric vehicles, thatfulfils the high demands of the automo-bile industry. Semikron has been namedby General Motors “Supplier of the Year”in recognition of the optimized powerelectronics system developed for GMfuel cell automobiles.
Optimizing thermal resistance in themodule design is the designer’s goal.Improvement in silicon switches whichminimize switching losses and conduc-tion losses in IGBTs has been achieved.With improved silicon thinning process-es, thinner die have become a reality.Thinner die equate to a better thermalresponse. Module manufactures aremoving to more dense packages andhigher break down voltages. In the past,the major improvements for efficiencyhave been made by optimizing the sili-con. Now the silicon has reached a pointwhere improvement in connecting andpackaging technology contribute a high-er amount to the total performance ofsystems. Wire bonding is being replacedfor power packaging by alternate tech-nology like solder or pressure contact.
The IGBT had become the switch ofchoice. Thank you to Frank Wheatleyand his college Dr. Hans Becke at RCA.They got the critical important US patent4,364,073 that had changed the world ofpower electronics.
10 Power Systems Design Europe September 2004
By Paul Greenland, Marketing Director of National Semiconductor's
Power Management Products Group
In recent years we have seen a revolu-tion in the distributed power architec-ture for the rapidly evolving informa-
tion infrastructure. We start with theintroduction of the Intermediate BusArchitecture followed by the advent ofdigital control and the trend towards themanageability of on-board power.
Intermediate Bus ArchitectureRoughly five years ago, power man-
agement met an inflection point in sys-tem design. The forced air cooling budg-et for racks in telecom and datacomapplications had reached a ceiling. Theproliferation of DSPs, FPGAs and digitalASICs, driven by the end-customer’sinsatiable thirst for bandwidth and con-tent, had increased the number andcomplexity of loads to the point at whichthe conventional distributed power archi-tecture, using a single isolated multi-out-put modular DC-DC converter on eachcard became inefficient. The answerwas to separate the isolation, step-downand point-of-load regulation into two dis-tinct stages replacing the single multi-output brick.
This metamorphosis is not without itschallenges; each stage has to occupyless than half the volume of the originalsolution and the series combination has to have higher overall efficiency.Typically the architecture uses a looselyregulated first stage which performs theisolation and step-down function, with aprecision second stage at the point ofload. The first stage is called theIntermediate Bus Converter (IBC). TheIBC is usually regulated against linevoltage variation, load regulation iscoarse, typically ±10%. Conversely, regulators at the point of load have
tight load regulation, typically < ±1% andare not isolated. The primary distributedbus is -36 V to -72 V dc or +43 V to +53V dc, for telecom or datacom respective-ly. The intermediate bus is usually 8 Vto 14 V dc.
Digital PowerEconomy, flexibility and reliability are
the primary motivations for consideringdigital control. As process geometrieshave shrunk, digital implementation canoften be achieved in a smaller die area,with lower power consumption than itsanalog counterpart. Digital controloffers the promise of improved noiseimmunity and sophisticated adaptive on-the-fly control allowing the power supplydesigner to consider power factor cor-rection and resonant conversion topolo-gies hitherto regarded to be too complexfor analog control. The transition to digi-tal control is however, a risky proposi-tion. Notoriously conservative powersupply designers who have investedyears of hard won experience in analogcontrol have to learn to use a whole newvocabulary and toolset. Up to now digitalcontrol has been focused on applica-tions where the time constants in theload system have been long enough topermit real-time calculation of pulse
width, and reference to look up tables. A good example is battery charging withpower factor correction, for instance, the“Rectifier” in a telephone exchange.
Power System ManageabilityComplex loads, particularly FPGAs
and DSPs require separate supplies forcore and I/O. The core processor tech-nology often operates at, or below, onevolt, while the I/O is held at a conven-tional potential by the communicationinterface standard. Since these sub-cir-cuits are often separated in the IC, by areverse biased ESD diode, the powerrails have to be applied and removed in a particular order, tracking one anoth-er to prevent latch-up and potentialdestruction. Furthermore, sophisticatedloads often require “voltage margining”during automatic test procedures andmay give an indication of their statusand immediate power consumption forenergy efficient application. On-boardpower manageability includes the capa-bility to dynamically configure the powersupply to optimize a sensed parametersuch as temperature, throttle airflow or improve signal integrity, and to automatically compensate for the sensor’s characteristics.
In summary power management isgaining recognition as a true enablingtechnology, capable of differentiating theperformance of the final system. The lat-est developments in distributed powerarchitectures are prime examples ofwhere timely collaboration with powermanagement semiconductor supplierscan yield sustainable advantage.
www.national.com
12 Power Systems Design Europe September 2004
COVER STORY
Powering the motion
Inverter technology is the key to cost-effective and efficient motor drives. As a solution, Fairchild
has developed a broad range of Smart Power Modules tailored to variable speed drives.
SPM series are designed to bring the customers both high performance and lower cost, and to
make electronic motor drives efficient, compact, easy and fast to design, rugged and less risky.
By Sung-il Yong and Bum-Seok Suh, Fairchild Semiconductor
Concerns about the environmentand energy conservation haveresulted in new regulations and
recommendations from governmentagencies throughout the world. Lowpower drives both in consumer appli-ance and general industrial applicationshave shown a rapid growth in recentyears, increasing the need for low powermodules. SPM (Smart Power Module)has established a dominant position inthese application areas with its com-pactness, functionality, reliability andease of user interface.
From 1999, when the SPM series wasfirst developed, to the present, Fairchildhas manufactured millions of 600V SPMseries with the power range of 400W~3.7kW in consumer appliances and lowpower general industry applications.
This article will detail the SPM designconcept and its implementation of semi-conductor (power devices and controlICs) technology, package technology,and system technology mainly throughthe newly developed SPM3 and SPM5.Benefits of using SPM inverters will alsobe discussed.
SPM Design Concept The key SPM design concept is to
create a low power module with bothimproved reliability achieved by applying
the existing IC and LSI transfer moldpackaging technology to the SPM. SPMstructure is relatively simple: powerchips and the IC chips are directly diebonded on the copper lead frame, thebare ceramic material is attached to theframe, and then molded into epoxyresin. In comparison, the IPM is madeof power chips bonded on the metal orthe ceramic substrate and the ICs andthe passive components assembled onthe PCB, which in turn is assembled intoa plastic or epoxy resin case and thenfilled up with silicon gel. The SPM great-ly minimizes the number of parts countand material types, optimizing assemblyprocess and overall cost. To the left infigure 1 is SPM3 and to the right isSPM5. Their relative sizes are shownnext to a US quarter coin.
The second important design conceptis the implementation of a product withsmaller size but higher power rating. Of
the low power modules released to date,SPM3 has high power density with a3A~30A rated product built into a singlepackage outline.
The third design concept is userdesign flexibility to enable use in a widerange of applications. For example,there are two major flexibility features in the SPM3 series. First is the 3-N ter-minal structure where the IGBT inverterbridge emitter terminal is separated. Inthis type of structure, shunt resistancecan be used in each 3-N terminal toeasily detect inverter phase current.Second is high-side IGBT switchingdv/dt control made possible by the inser-tion of appropriate impedance cell in theSPM. Depending on how the impedancecell is designed, the high-side switchingslope can be adjusted so that criticalEMI problems may be easily dealt with.
Figure 1. SPM3 and SPM5 compared to a quarter coin.
14 Power Systems Design Europe September 2004
COVER STORY
The internal block diagram of theSPM3 is shown in Figure 2 (a) andSPM5 is shown in Figure 2 (b).
SPM3 is a 3-phase IGBT inverter with3 HVICs, 1 LVIC, 6 IGBTs and 6 FRDs.
SPM5 is a 3-phase MOSFET inverteroptimally designed for use with lowpower applications. It has 6 powerMOSFETs and 3 half bridge drive ICsbuilt in. The detailed features and inte-grated functions of SPM3 and SPM5 are as follows.
Features of SPM3:• 600V/3A to 30A rating in one package
(with identical mechanical layouts)• Low-loss efficient IGBTs and FRDs
optimized for motor drive applications• High reliability due to fully tested
coordination of HVIC and IGBTs• 3-phase IGBT inverter bridge includ-
ing control ICs for gate driving andprotection
• High-side: Control circuit undervoltage (UV) protection (withoutfault signal output)
• Low-side: UV and short-circuit(SC) protection through externalshunt resistor (with fault signaloutput)
• Single-grounded power supply andopto-coupler-less interface due tobuilt-in HVIC
• High-active input signal logicresolves the startup and shutdownsequence constraint between thecontrol supply and control input pro-
viding fail-safe operation with directconnection between the SPM and a3.3V CPU or DSP. Additional exter-nal sequence logic is not needed
• Divided negative DC-link terminalsfor inverter current sensing applications
• Isolation voltage rating of2500Vrms/min
• Very low leakage current due toceramic heat-sink and DBC substrate.
Features of SPM5:• 500V, 0.5A, 1A and 250V 1A rating,
3 - phase MOSFET inverter bridgeincluding control ICs for gate driving
• High reliability due to fully testedcoordination of HVIC and MOSFETs
• Single-grounded power supply andopto-coupler-less interface due tobuilt-in HVIC
• High-active input signal logicresolves the startup and shutdownsequence constraint between thecontrol supply and control input pro-viding fail-safe operation with directconnection between the SPM and a3.3V CPU or DSP. Additional exter-nal sequence logic is not needed
• 3 divided negative DC-link terminalsfor inverter current sensing applica-tions
• Typical switching frequency of 15kHz• Isolation voltage rating of 1500Vrms/min.
Semiconductor Technology, POWERDevices—IGBT, FRD and MOSFET
The performance upgrade of SPM3,which consists of 3-phase IGBT inverter
circuits, is basically the result of techno-logical development of power devices(IGBT and FRD). The fundamentaldesign rule of power devices is thereduction of chip size and the increaseof current density. The IGBT applied toSPM was newly developed by Fairchild.Through optimized PT planar IGBTdesign, it maintains the SOA (SafeOperating Area) suitable for motor con-trol application while dramatically reduc-ing the on-state loss (VCE(SAT) = 1.6V)and turn-off loss (EOFF = 60mJ@25∞C). It also implements smoothswitching performance without sacrific-ing other characteristics. The FRD is ahyperfast diode that has low forwardvoltage drop (an important factor ininverter applications) along with softrecovery characteristics.
In the 3-phase MOSFET inverterSPM5, the MOSFET’s internal bodydiode is used as a free wheeling diodefor the implementation of a more com-pact structure. The MOSFET used inSPM5 was primarily designed to havean outstanding body diode recoverycharacteristics as well as the implemen-tation of noise immunity and switchingperformance for motor control applica-tion. By optimizing gate resistance,dV/dt was implemented at below2kV/ms to suppress the resonance ofgate signal and to reduce EMI.
Semiconductor Technology, ControlIC—LVIC, HVIC
In the SPM inverter, the HVIC andLVIC were designed to have only theminimum necessary function suitable forlow power inverter drive. The HVIC hasa built-in high voltage level shift functionthat enables the ground referencedPWM signal to be sent directly to theSPM’s assigned high side IGBT gate circuit. This built-in function enablesopto-coupler-less interface, making itpossible to design a very simple system.In addition, with a built-in under-voltagelockout (UVLO) protection function, itinterrupts IGBT operation under controlsupply under-voltage conditions.Because the charge-pump mode, whichinterlocks to the low-side PWM outsideof the SPM, can be used as the high-side driving power, it can be driven with
Figure 2. Block Diagrams of SPM3 and SPM5.
www.powersystemsdesign.com 1716 Power Systems Design Europe September 2004
a 15V single control supply. This is notnecessary to have three isolated voltagesources for the high-side gate driveused in inverter systems that use con-ventional power modules.
Recent progress in the HVIC technol-ogy includes chip downsizing throughthe introduction of wafer fine processtechnology, input logic change from theconventional low active to high activepermitting direct drive by 3V feed Micro-controller or DSP, low circuit current,increased noise immunity and good performance stability against tempera-ture variation.
Package TechnologySince heat dissipation is an important
factor limiting the power module’s cur-rent capability, the heat dissipation char-acteristics of a package is critical indetermining SPM performance. A trade-off exists between heat dissipation char-acteristic and isolation characteristic.The key to a good package technologylies in the implementation of outstandingheat dissipation characteristic withoutcompromising the isolation rating.
In SPM3, a technology was developedin which bare ceramic with good heatdissipation characteristics is attacheddirectly to the lead frame. For expansionto a targeted power rating of 20A/30Awithin a single package, DBC (DirectBonding Copper) technology wasapplied. This made it possible toachieve optimum trade-off characteris-tics while maintaining cost-effectiveness.
In SPM5, special epoxy resin wasused with optimized thermal conductivityand insulation characteristic. At thesame time, the thickness of the insula-tion layer, which is also composed ofresin, has been carefully optimized tomeet the required specification both interms of insulation level and thermalresistance.
Figure 3 shows cross sections of theSPM3 and SPM5 package. As seen inFigure 3 (a), the lead frame structurewas bent to secure the required electri-cal spacing. In Figure 3(b), the leadframe and the DBC substrate are beingdirectly soldered in the DBC-SPM3.
Inverter System TechnologyThe package has been designed to
satisfy the basic creepage and clear-ance spacing related safety regulations(UL, IEC, etc.) required in inverter sys-tems. In SPM3, 3mm creepage and4mm clearance was secured in all areaswhere high voltage is applied. In addi-tion, the Cu frame pattern and wire con-nection have been optimized with theaid of computer simulation for less para-sitic inductance, which is favorable tothe suppression of voltage surge at highfrequency switching operation.
HVIC is sensitive to noise since it isnot a complete galvanic isolation struc-ture but is implemented as a level shiftlatch logic using high voltage LDMOSthat passes signals from upper side gateand lower side gate. Consequently, itwas designed with sufficient immunityagainst such possible malfunctions aslatch-on, latch-up, and latch-off causedby IGBT switching noise and system
outside noise. Fairchild’s SPM designalso taken into consideration the possi-bility of high side malfunction caused byshort PWM pulse. Since the low voltagepart and the high voltage part are con-figured onto the same silicon in theHVIC, it cannot operate normally whenthe electric potential in the high voltagepart becomes lower than the ground ofthe low voltage part. Accordingly, suffi-cient margin was given to take intoaccount the negative voltage level thatcould cause such abnormal operation.Soft turn off function was added tosecure basic IGBT SOA (Safe OperatingArea) under short circuit conditions.
Advantage of SPM-inverter Drivesand SPM Inverter Engine Platform
SPM3 was designed to have 3A~30Arated products built into a single pack-age outline. Figure 4 shows the junctionto case thermal resistance at each cur-rent range of the SPM3.
Figure 3. Cross Sections of SPM3 and SPM5
As seen in the figure, in the 20Aand 30A range, intelligent 3-phase IGBTmodule with high power density (Sizevs. Power) was implemented. Accordingly,in the low power range, inverter systemdesigners are able to cover almost theentire range of 0.1KW~2.2KW rating ina single power circuit design usingSPM3. Since circuitry and tools canbecome more standardized, productdevelopment and testing process aresimplified, significantly reducing devel-opment time and cost. Through controlboard standardization, overall manufac-turing cost will be substantially reducedas users are able to simplify materialspurchasing and maintain manufacturingconsistency.
Noise ReductionSmall package and low power loss
are the primary goals of low power mod-ules. However, in recent years, attempt-ing to reduce power loss through exces-sively fast switching speed has givenrise to various challenges. Excessiveswitching speed increases the dV/dt,di/dt, and recovery current and createschallenges such as large EMI(Electromagnetic Interference), exces-sive surge voltage, and high magnitudeof motor leakage current. Such prob-lems increase system cost and caneven shorten motor life. SPM seriessolve these problems by adjusting the
switching dV/dt to below 3kV/usec (typi-cal) through advanced gate drive imped-ance design.
Thanks to very low on-state voltageof the new generation IGBT and low for-ward voltage of FRD, an optimizedswitching speed meeting the low EMIrequirement has been realized in SPMwhile keeping the total power loss at alow level equal to or less than other lowpower modules.
Cost-effective Current DetectionAs sensorless vector control and other
increasingly sophisticated control meth-ods are applied to general industrialinverters and even in consumer appli-ance inverters, there is a growing needto measure inverter phase current. SPMfamily has a 3-N terminal structure inwhich IGBT inverter bridge emitter ter-minal is separated. In this type of struc-ture, inverter phase current can be easi-ly detected simply by using externalshunt resistance.
High ReliabilityThe wire-to-chip junctions and the
chip-to-frame junctions have beenenforced in a transfer mold package tomake it endure severe thermal stress. In particular, the wire-to-chip junctionendurance against steep temperatureswing caused by rapid load variation
has been substantially improved. Powercycle results show that SPM is capableof over ten million power cycles at anaverage chip junction temperature swingof 25∞C. This makes SPM suitable notonly for home appliances, which usuallywork under a relatively constant load,but also for a typical servo operationcharacterized by frequent and dramaticload changes.
ConclusionToday, SPM has positioned itself as
strong inverter solution in low powermotor control. With its compact size,optimized performance, high reliability,and low cost, the SPM family is acceler-ating the inverterization not only of lowpower industry applications but also ofconsumer appliances. Fairchild will con-tinue its effort to develop the next gener-ation of SPMs optimized for a wider vari-ety of applications and with higherpower rating in mind.
For more information on Fairchild’sSPM products, please visit
http://www.fairchildsemi.com/offers/discrete/spm/index.html
Figure 4. Junction-to-case Thermal Resistance according to Current Rating of SPM3 Line-up.
COVER STORY COVER STORY
www.fairchildsemi.com
www.powersystemsdesign.com18 19
MAGNETICS
Power Systems Design Europe September 2004
Accurate control of the moving armature
System identification experiments and robust controller design method are presented in
the case of a nonlinear electromagnetic actuator.
By A. Forrai, T. Ueda and T. Yumura, Mitsubishi Electric Corp., Japan
The considered control problemrequires accurate control of themoving armature. The small con-
tact velocity, known as: ‘soft landing’, isa very important consideration becausehigh contact velocities correlate withcomponent wear and noise.
Moreover, soft landing of the armaturehas to be achieved within a limited time.These two requirements are obviouslyconflicting. Other control difficulties arisefrom: the nonlinear characteristics of theactuator, control input saturation, disper-sion due to the manufacturing and set-ting process, etc.
Similar control problem arises in thecase of electromagnetic valve actuatorsin combustion engines, and if the arma-ture is controlled around an operatingpoint (magnetic levitation) there areapplications such as: high-speed trans-portation, magnetic bearings, artificialheart, clean room applications in thesemiconductor industry, etc.
Modelling and System IdentificationThe basic structure of the electromag-
netic actuator is presented in Figure 1.
The related mathematical model of theinvestigated electromagnetic actuatorcan be written as:
(1)
where u – applied voltage, i – current,R – coil resistance, y – air-gap and Y =Y(i,y) is the magnetic flux, which is cur-rent and air-gap dependent.
The equation of motion is given by:
(2)
where m is the moving mass, Fs is thespring force and Fm is the magnetic
force computed using the magnetic co-energy (the friction can be neglected).
The control problem can be viewed asa general case of a magnetic levitationproblem: the nonlinear system can belinearized around an equilibrium pointnoted by (i0, y0) using Taylor seriesexpansion. The open-loop transfer function is:
(3)
where b1 and b2 are positive constantsand the symbol D suggests small varia-tions around the equilibrium point.
For simplicity let us consider that thearmature is controlled around an equilib-rium point, then the easiest way to com-pensate the system nonlinearity is byadding a constant bias current denotedby ib=Ib (or a constant bias voltage incase of voltage control configuration ub= Ub=RIb).
A much robust approach is exact lin-earization of the plant, in this case thebias current equals the equilibrium current:
which is armature position and springforce dependent.
This nonlinear function f can be
(4)
obtained by measurements and can beimplemented in real-time, however, inthe industry preference is given to sim-ple compensation laws.
Therefore, we consider the bias cur-rent to be the measured current, whichunder control asymptotically convergesto the equilibrium current.
(5)
This approach is called asymptoticallyexact linearization [2]. From energeticpoint of view the compensation law cov-ers exactly the Ohmic losses ubib = Ri2,which means that if the system is stabi-lized around an equilibrium point thisnonlinear compensation will not make itunstable. In case of voltage control con-figuration the compensation law has theform ub = Ri.
The condition of asymptotic conver-gence i Æ i0 can be assured if the linearcontrol system (around an equilibriumpoint) is internally stable. Therefore,considering a robust control frameworkfor controller design is essential (robuststability assures internal stability) [3].
The first step in controller design issystem identification—a model alwaysmust be derived from experimental data.Due to open-loop instability, experimen-tal models for the electromagnetic actu-ator are obtained through closed-loopexperiments only.
Therefore, the first step was to design,through trial and error procedure, a controller, which can stabilize the sys-tem, when the nonlinearity has beencompensated using asymptotically exact linearization.
The system has been stabilizedaround different equilibrium positions: y0= 0.15 mm, y0 = 0.2 mm, y0 = 0.25 mmand y0 = 0.35 mm.
Closed-loop identification has beenperformed considering an indirectapproach: we assume that the referencesignal and the regulator to be known, weidentify the closed-loop system from ref-erence input to output, and retrieve fromthat the open-loop system, making useof the known regulator.
The system is identified on the basisof measured input/output data, usingwell-known Auto-Regressive eXogenous(ARX) model, when the input signal isthe Pseudo-Random Binary Signal(PRBS) [4].
Defining the sample period of thePRBS as Ts and noting with M the maxi-mum length period it can be shown thatthe frequency range of the PRBS is:
(6)
System identification experimentshave been performed in two differentfrequency ranges defined by: 4 rad/sec< wlow < 62 rad/sec, which corre-sponds to Ts = 0.05 s and 20 rad/sec <whigh < 314 rad/sec, which correspondsto Ts = 0.01 s and around different equi-librium points, when the air-gap wassuccessively 0.15 mm, 0.2 mm, 0.25mm and 0.35 mm.
Experimental results around the equi-librium point y0 = 0.15 mm are present-ed in Figure 2.a and Figure 2.b wherethe measured output (solid line 1) iscompared with the estimated output(dotted line 2). Basically there is a goodagreement between the real plant and
derived plant model.The identified transfer functions
(around different equilibrium points anddifferent frequency ranges) are validatedin frequency and time domain and thenominal model is chosen using errorminimization. The nominal plant is given by:
(7)
Robust Controller Design andExperimental Results
In the aim to assure ‘soft landing’ ofthe moving armature a positioning control approach has been considered,when the reference input signal is a ramp.
The block diagram of the proposedrobust control system with direct voltagecontrol is presented in Figure 3, wherethe asymptotically exact linearization(AEL) block already has been descried.Moreover, the linearized plant is modi-fied by rate feedback to improve the dis-turbance rejection properties against thespring force—the modified plant is notedby G(s).
Figure 1. The electromagnetic actuator. Figure 2. System identification under closed loop.
Figure 3. The control structure.
MAGNETICS
20 Power Systems Design Europe September 2004
The controller design specificationsare summarized as follows:
• The armature speed denoted by vmust be between: 1 mm/s < v < 2mm/s - this will assure ‘soft landing’and armature pull-up/release timeless than 0.5 seconds;
• The order of the robust controllershould be as low as possible;
• The sensitivity function should beminimized as much as possible (itsminimization is also limited by thelowest possible gain due to theopen-loop instability).
Considering a mixed sensitivityapproach the robust performance condi-tion (which assures robust stability andperformance) is written as:
(8)
where S(s) is the sensitivity transferfunction, T(s) is the complementary sen-sitivity transfer function and WS(s) anWT(s) are the performance and robust-ness weighting functions.
The robustness weighting functionWT(s) is derived based on system iden-tification experiments. The multiplicativeuncertainty model for the modified plant is given by:
(9)
where Gn(s) is the nominal plant mod-ified by rate feedback. The weightingfunction WT(s) is made larger than themultiplicative uncertainty at any frequen-cy |Dm(s)| < |WT(s)|.
The performance weighting functionWS(s) is chosen by the designer, takinginto account that the reference signal isa ramp, for asymptotic tracking the sen-sitivity transfer function must have atleast two zeros at the origin, this meansthe order of WS(s) transfer function is atleast two.
The robust controller is designed sys-tematically according to the robust con-trol theory and a fourth-order controlleris obtained (which can be reduced to athird-order controller). The transfer func-
tion of the controller is discretized usingthe bilinear Tustin transformation withthe sampling time Ts = 0.001 s and isimplemented on a TMS 320C40 DSPboard. The armature current is sensedusing LEM current sensors and thearmature position is sensed by infra-redsensors, having operating temperaturerange up to 85∞C degrees.
In Figure 4 is shown the armature cur-rent and position variation under control,when the spring force undergoes varia-tions ±5% according to the manufactur-ing dispersion. The solid line 1 corre-sponds to the highest spring force, thedashed line 2 to the nominal springforce and the dotted line 3 to the lowestspring force. In all cases soft landing ofthe armature is achieved, according tothe design specifications.
ConclusionsThe article focused on system identifi-
cation experiments and robust controllerdesign applied for an electromagneticactuator.
The nonlinear system has been lin-earized using asymptotically exact lin-earization, which is easy to implementand from passivity based control theoryhas a nice interpretation—it coversexactly the Ohmic losses.
First, due to open-loop instability sys-tem identification experiments havebeen performed under closed-loop indifferent frequency ranges and for differ-ent equilibrium positions. Next, therobust controller approach has beenconsidered during the controller synthe-sis. Finally, the designed control systemhas been implemented on a DSP boardand tested experimentally – good
robustness and performance (‘soft land-ing’) have been achieved.
The performance could be improved,by considering a linear parameter vari-ant controller synthesis approach, whichallows a lower uncertainty bound andhigher control bandwidth.
References1. A.Forrai, T.Ueda, T.Yumura -
Asymptotically Exact Linearizationand Robust Control of anElectromagnetic Actuator, Proc.PCIM’04 Conference, Nuremberg,Germany, 2004, Vol. II pp. 788-793.
2. L.Li, T.Shinshi, A.Shimokohbe -Asymptotically exact linearizationsfor active magnetic bearing actua-tors in voltage control configuration.IEEE Trans. on Control SystemsTechnology, Vol. 11, No. 2, 2003,pp. 185-195.
3. J.C.Doyle, B.A.Francis,A.R.Tannenbaum - Feedback con-trol theory. New York, Mcmillan 1992.
4. L.Ljung - System identification -theory for the users. New York,Prentice-Hall 1987.
A. Forrai, T. Ueda and T. Yumura;Mechatronics Department
Advanced Technology R&D CenterMitsubishi Electric Corp., Japan
Tel: +81 6 6497 7759 Fax: +81 6 6497 7725E-mail: [email protected]
Figure 4. The system response
www.mitsubishi.com
MAGNETICS
Global revenue for all types ofpower-management semicon-ductors will reach an estimated
$20.1 billion in 2004, up 24.3 percentfrom $16.2 billion in 2003, according toiSuppli Corp. Revenue will grow to $29.5billion in 2008, rising at a CompoundAnnual Growth Rate (CAGR) of 12.7percent from 2003. However, revenuegrowth will slow in 2005 and nearly stallin 2006 before beginning another growthcycle, conforming with electronics andsemiconductor industry trends.
iSuppli believes 2004 will representthe peak year for growth in the power-management semiconductor realm inthe current cycle. This year also will markthe zenith of the present semiconductorcycle, with worldwide chip revenue rising24.4 percent in 2004. Electronic equip-ment sales also will peak this year, ris-ing 10 percent.
Revenue growth in 2004 for power-management semiconductors is beingaided by high Average Selling Prices(ASPs). Sellers have the upper hand inthe power-management area in 2004,and have been able to increase prices.
Power-management semiconductors
benefit from broad usage in all electron-ic segments of electronic equipment.Thus, there is a close correlationbetween power-management semicon-ductor sales and end-equipment revenue.
Power Goes MobileHowever, beyond the general growth
of the semiconductor and electronic-equipment markets, various product areasare driving increased sales of power-management semiconductors this yearand further in the future. A major dynamicdriving power-management semicon-ductor sales growth is the increasingnumber of battery-operated products onthe market, such as mobile PCs andwireless handsets, which have morestringent power-management require-ments. Beyond mobile products, power-management semiconductor sales arebeing boosted by the proliferation ofelectronics into new areas that havegrowing power needs, such as the automotive market.
Notebook PCs will enjoy 29 percentunit growth in 2004, compared to only 6percent for desktops. Notebook comput-ers have greater power-managementrequirements. Thus, the migration tonotebooks means the PC market will
www.powersystemsdesign.com 2322 Power Systems Design Europe September 2004
Sales boosted by robust increases in mobile-PC, automotive markets
With the semiconductor and electronic-equipment markets set for robust growth in 2004,
the power-management chip segment also is on its way to a great year.
By Derek Lidow, iSuppli
Figure 1. iSuppli’s forecast for power-management semiconductors.
MARKETWATCH
www.powersystemsdesign.com 25
Pho
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24 Power Systems Design Europe September 2004
increase its demand for power-manage-ment semiconductors in 2004 andbeyond, iSuppli believes.
Meanwhile, sales of power-manage-ment semiconductors to the automotivemarket will rise to an estimated $2.9 bil-lion in 2004, up 31.7 percent from $2.2billion in 2003. Revenues will nearlytriple from 2002 to 2008, iSuppli predicts.Automotive power-management semi-conductor revenues will grow to $5.3 bil-lion in 2008, rising at a CAGR of 18.5percent from $1.9 billion in 2002.
Sales growth of some power-manage-ment components to the automotivemarket will be boosted by the rising pop-ularity of hybrid vehicles, which are pow-ered by gas and electric engines. Suchautos use between $500 and $1,000 ofpower electronics in each vehicle, gen-erating a huge opportunity for compo-nent suppliers.
Power-Management SemiconductorProduct Outlook
The fastest-growing major segment ofthe power-management semiconductormarket is power ICs. Within the powerIC category, the voltage regulator andreference segment dominates, withmore than $4.3 billion in revenue.
The voltage regulator category con-sists of three different types of ICs: lin-ear regulators, switching regulators andvoltage reference and other devices.
Voltage regulator revenue will rise to$5.5 billion in 2004, up 26.9 percent from$4.3 billion in 2003, iSuppli predicts. Revenuewill rise at a 17.5 percent CAGR from $4.3billion in 2003 to $9.7 billion in 2008.
In the power discrete area, powertransistor revenue will reach $7.6 billionin 2004, up 26.5 percent from $6 billionin 2003. Revenue will grow to $10.5 bil-lion in 2008, rising at a CAGR of 11.8percent from 2003.
Within the power-discrete segment,power MOSFETs will post a notable performance in 2004, with sales rising to $4.98 billion for the year, up 30.5 per-cent from $3.8 billion in 2003. PowerMOSFET revenue will reach $7.3 billionin 2008, rising at a CAGR of 13.9 per-cent from $3.8 billion in 2003.
Competitive DevelopmentsWith demand coming from multiple,
fragmented markets, and divided evenlybetween discrete and IC device types,the power-management semiconductorarea has no clear dominant supplier.
The names of the top-10 power-man-agement semiconductor suppliers wereunchanged from 2001 to 2002. However,there was some changing of chairs amongthe top competitors. STMicroelectronicssolidified its number-one ranking in 2002on the strength of leadership positions inboth power ICs and power dis-cretes. FairchildSemiconductormoved up to thenumber-two rank,up from numberthree in 2001, alsobased on a goodbalance of strengthin power ICs anddiscretes. At thenumber-three ranking, TexasInstruments movedup one place fromthe prior year. TIachieved this levelwithout any partici-pation in power dis-cretes, but it lever-aged its leadershipin power ICs bygrowing revenue at twice the industryaverage rate.
InternationalRectifier, with itsstrong focus in thepower MOSFETarea, but with a
much weaker position in power ICs,maintained essentially flat sales in 2002and slipped from the number-two posi-tion in 2001 to the number-four spot for2002, while the power-managementmarket grew 7 percent.
Power UpPower-management ICs occupy an
enviable market position. Their prospectsare limited only by the level of salesgrowth in electronic equipment and theincrease in the need for power manage-ment in products. With both of these areasset to increase over the next few years,the power-management IC market is infor continued growth over the long term.
Derek Lidow is president and chiefexecutive officer of the market researchfirm iSuppli Corp., based in El Segundo,Calif. Contact him at
Figure 2. iSuppli’s ranking of the top-five suppliers of power-managementsemiconductors in 2002.
www.iSuppli.com
MARKETWATCH
www.powersystemsdesign.com 27
AUTOMOTIVE ELECTRONICS: PART II
Integrated starter alternators, synchro-nous rectifier alternators, electricalpower steering systems, and brush
and brushless dc motor drives employpower semiconductor switches to con-trol turn-on, turn-off, speed and directionof travel. These power semiconductorswitches must operate reliably in theharsh automotive environment, regard-less of noise transients and voltage variations. Meeting this need is a newTrench HEXFET (MOSFET) family. Toensure reliability, all members of thisTrench MOSFET family are testedaccording to the AEC Q-101 specifica-tion that guides electronic componentselection and testing for the automotiveenvironment.
Trench MOSFETs employs the sameschematic configuration of the older planar MOSFETs, as shown in Figure 1.The new Trench MOSFETs offer signifi-cant advantages over the older genera-tion Trench MOSFETs and also someimprovements over the older planarMOSFET technology. To understand thenew Trench MOSFET improvements,
we have to investigate several parame-ters critical to the performance of powersemiconductors employed in automotiveapplications:
• Blocking voltage (BVDSS)• Maximum avalanche energy (EAR)• On-resistance (RDS(ON))• Maximum junction temperature
(TJ(max))• Continuous drain current (ID)• Safe operating area (SOA)• Gate charge (QG)
Blocking voltage is the maximum volt-age that can be applied to the MOSFET.When driving an inductive load, such asa motor, this includes the applied volt-age plus any inductively induced volt-age. With inductive loads, the voltageacross the MOSFET can actually betwice the applied voltage. Blocking volt-age ratings of International Rectifier’snew Trench MOSFET family are 30V,40V, 55V, 75V and 100V.
The automotive environment can pro-duce repetitive high voltage transientscaused by fast current changes, such as starting the engine, which may forceMOSFETs into an avalanche condition.There are two possible failure modescaused by the avalanche condition thatcan destroy a MOSFET. The mostdestructive is “bipolar latching” thatoccurs if the device current causes avoltage drop across its internal deviceresistance, resulting in transistor actionand latching of the parasitic bipolarstructure of the MOSFET. A second fail-ure mode is thermal, which occurs if theavalanche condition raises the device
The right device for automotive electronics
The Q101 specification defines the minimum stress test-driven requirements and references
test conditions for qualification of discrete semiconductors (transistors and diodes) for
the automotive environment
By Anthony Murray, International Rectifier
Figure 1Trench MOSFET schematic.
26 Power Systems Design Europe September 2004
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AUTOMOTIVE ELECTRONICS: PART II
temperature above its maximum junc-tion temperature.
The new Trench HEXFET technologyoffers an avalanche capability compara-ble to industry-leading planar technologyand up to twice that of some currentlyavailable trench products. To ensuresatisfactory performance, all the devicesin this automotive-oriented family arefully characterized for repetitive ava-lanche energy (EAR) up to their maxi-mum junction temperature, TJ(max). Thehigher the EAR, the more rugged thedevice. Figure 2 shows the maximumavalanche energy vs. temperature forthe IRF2804 rated at 40V BVDSS.
Trench technology provides the desir-able characteristics of high avalanchecapability and low on-resistance, orRDS(ON). On-resistance consists of theresistance of the MOSFET die plus itslead resistance, which is a function ofthe package that is employed. The newautomotive-specific, Trench HEXFETpower MOSFET technology provides15% lower device on-resistance per unitarea than existing benchmark technolo-gies. And, the new Trench technologyallows 10% lower on-resistance temper-ature coefficient. On-resistance is tem-
perature dependent, as seen in Figure3, which plots normalized on-resistancevs. temperature for the IRF2804 with ID= 75A and VGS = 10V (VGS is gate-to-source voltage).
On-resistance is important because itdetermines the power loss and heatingof the power semiconductor. The lowerthe RDS(ON) the lower the device powerloss and the cooler it will operate. This isparticularly important in automotiveapplications where the nominal operat-ing temperatures usually exceed 125°C.Low on-resistance drastically reducesheat-sinking requirements in manyapplications, which lowers parts countand assembly costs. In many applica-tions, the low on-resistance also elimi-nates the need to parallel MOSFETs for low on-resistance, which leads toimproved reliability and lower overallsystem cost than previous MOSFETgenerations.
Maximum junction temperature is afunction of the electrical characteristicsof the device itself, as well as the pack-age employed. Package thermal proper-ties determine its ability to extract heatfrom the die. The junction-to-ambient(RqJA) thermal resistance of the device
is a measure of its ability to extract heat. The lower the thermal resistance,the more efficient the package is in eliminating heat. In some cases, a heatsink may be required to maintain thedevice junction temperature below itsmaximum rating.
Continuous drain current establishesthe ability of the MOSFET to drive aspecific load. This value can be limitedby the MOSFET’s package. When oper-ated in the pulsed mode, the MOSFET’sdrain current can be several times itscontinuous rating. In the pulsed modethe pulse width and duty cycle deter-mine safe drain current and devicepower dissipation.
Safe operating area is exactly whatthe name implies. The maximum safeoperating area depends on the draincurrent and VDS (drain-to-source volt-age). Figure 4 shows the maximum safeoperating area for the IRF2804.
Gate charge affects the highest reli-able switching frequency of the MOS-FET. The lower the gate charge, thehigher the frequency. Operation at higher frequencies allows use of lowervalue, smaller size capacitors and
Figure 2. Maximum avalanche energy vs. temperature forthe IRF2804 rated at 40V BVDSS.
Figure 3. Normalized on-resistance vs. temperature forthe IRF2804 Trench MOSFET.
30 Power Systems Design Europe September 2004 www.powersystemsdesign.com 31
AUTOMOTIVE ELECTRONICS: PART II
inductors, which can be significant fac-tors in system cost. A low gate chargealso makes it easier to drive the MOS-FET, however, automotive engineerssometimes need to trade-off switchingfrequency with ElectromagneticInterference (EMI) considerations, whichfollow very strict guidelines in the auto-motive envoirnment. The new devicesexhibit lower gate charge than existingplanar technologies. Gate charge is afunction of VGS, ID, and VDS, as shown in Figure 5.
AEC Q-101The Automotive Electronics Council
(AEC) consists of two committees thatestablish the requirements for the Q-101specification: the Quality Systems andthe Component Technical committees.Today, the committees includes repre-
sentatives from the sustaining membersDaimlerChrysler, Delphi Delco ElectronicsSystems, Visteon Automotive Systemsand other associate members. TheComponent Technical committee estab-lishes standards for reliable, high qualityelectronic components. Componentsmeeting these specifications are suit-able for use in the harsh automotiveenvironment without additional compo-nent-level qualification testing.
The Q101 specification defines theminimum stress test-driven require-ments and references test conditions forqualification of discrete semiconductors(transistors and diodes) for the automo-tive environment. It does not relievesuppliers of the responsibility to meettheir internal qualification program.
Planar MOSFETs vs Trench MOSFETsFrom it very inception, planar MOS-
FET on-resistance depended on its cell density, that is, the number ofcells/mm3. However, there is an upperbound on cell density that limits the lowest value of on-resistance possible.
The Trench MOSFET structure verti-cally redirects the current flow in thedevice's channel in a direct pathbetween the topside source and thebackside drain contact. Figure 6(a) and6(b) show the vertical Trench and hori-zontal planar MOSFET cross-sections,respectively. The TrenchFET configura-tion avoids the parasitic series-JFETproblem inherent in planar DMOSdevices. Process refinements haveyielded devices with steadily increasingdensity and lower on-resistance.TrenchFET devices have achieved on-resistance less than 1mW for a 25mm2silicon die, exclusive of lead resistance.
IR response management is:Mike Wigg, International Rectifier Co Ltd, European Regional Centre, 439/445Godstone Road, Whyteleafe, Surrey.CR3 0BLTel; +44 (0)20 8645 8003Fax; +44 (0)20 8645 8077e-mail: [email protected]
www.irf.com
Figure 4. Safe operating area for the IRF2804 TrenchMOSFET.
Figure 5. Typical gate charge vs gate-to-source voltage forthe IRF2804 Trench MOSFET
Figure 6. MOSFET cross-sections: a TrenchFET; b Planar MOSFET.
www.powersystemsdesign.com 3332 Power Systems Design Europe September 2004
well as the effect upon the central doormodule which naturally also bears theload of multiple options.
Development target- mechatronicsThe limited space available in the mir-
ror housing allows only very compactlybuilt electronics, which in the end elimi-nates a multichip concept with severalpackages. The way out of this dilemmais the mechatronic mirror concept, inwhich all signals and actuator functions
are already pre-processed within themirror and only one bus connection andthe two supply leads are present. Forthe target monolithic solution, a 0.6µBCD (Bipolar Cmos Dmos) technologywas selected, which also allows the integration of an “embedded controller”,whose architecture is specified accordingto the ST 7 family from STMicroelectronics.This technology was chosen because itallows the possibility of integrating thepower and the digital parts in the samepiece of silicon.
The integrated controller monitors andcontrols all sensors and actuators. Allactuator drivers have such a layout thatthe SMD power package HIQUAD64can be used without additional cooling,allowing maximum flexibility of mount-ing. Below, Figure 3 shows the blockdiagram of the mirror driver designatedas UD13.
Table 1 shows the function and load-ing profile of the mirror actuators. Thegiven values are largely representativefor all mirror types and manufacturers.
Control of the mirror motorsThe UD13 contains four half-bridges
for the control of the motors for the mir-ror adjustment as well as the folding inof the mirror. Each half bridge is sepa-rately controllable from the controller sothat simultaneous operation is also pos-sible. The central half bridge, and alsothe half bridge branch for the fold inmotor offers a 200mOhm per transistor(25°C) and is hence capable of drivingall known motors with very low powerdissipation. In order to safe the other-wise normally used mechanical endswitches, the central half bridge allows abi-directional current measurement withwhich the blocking of the motor can bedetected. The current level can be readout from the controller over the ADC.
Consideration of the power dissipationThe mirror driver U13 has a total of
nine actuator drivers as well as a volt-age regulator and the position sensorsupply. All drivers in active operationgenerate a power dissipation, which intotal (taking into account the package,ambient temperature and heat removal
AUTOMOTIVE ELECTRONICS: PART II
Figure 2. Driving functions for a high end mirror showing significant level of harness complexity.
Figure 3. Mirror driver designated as UD13.
AUTOMOTIVE ELECTRONICS: PART II
LIN-Bus controlled smart-power chips to control exterior mirrors
A Smart-Power Chip with a Microcontroller-core, embedded in a mechatronic mirror concept
solves this problem with only three leads needed to the door module, including: power supply,
ground and LIN-Bus.
By Alberto Coen, STMicroelectronics
In the ever increasing need to supportsafety and comfort in passenger cars,more features are being added to
external mirrors. In addition to mirroradjustment and defrosting, which aretoday standard, electrochromatic con-trolled dimming, turn indicators, thedoor’s outside (puddle) lights, the fold-ing in of the mirror, and the storing of the mirror position are also becomestandard in automobiles. The multiplenew actuator and sensor functions however result in a significant costincrease, driving up wiring expenses to the door module.
Development trends in the area ofexterior mirrors
There have already been different tentative approaches in the area of amechatronic solutions, without giving up the concept of a central control module. Figure 1 shows some examplesof solutions with the resulting effect onthe count of the internal connectingleads. This shows the significant reduction in leads achieved by themechatronic approach.
The mirror has the highest lead countand hence offers the greatest savings
potential for the mechatronic approach.Experience shows that features thattoday command an additional price, aretomorrow’s standard equipment. Thismeans where today 5 leads are suffi-cient to provide the standard mirror
adjustment and heating, up to 19 leadswill be necessary, which can easilybecome a problem as the hollow spindleof the mirror joint has a limited capacity.Figure 2 shows a typical case for themaximum level of mirror equipment, as
Figure 1. A Actuator driver inside a separate moduleB Window winder combined with door moduleC Keyboard combined with door moduleD Actuator drivers dedicated to actuators (mechatronic)
www.powersystemsdesign.com 3534 Power Systems Design Europe September 2004
current (limited only by the pack-age) and function at a junctiontemperature up to 150 Celsius,which is the point where on-chipprotection intervenes. UD13includes a voltage regulator, line interface, power actuators, a micro (core and peripherals)and memories (RAM/EPROM).
The technology chosen for the mirror driver chip is a “MixedSignal + Power Process” solu-tion, which is designated asBCD5 at STMicroelectronics. Itoffers a comprehensive spec-trum of components from analogto digital functions including program memory and power drivers.
The UD013 concept is tightlylinked to the mechatronic con-cept. Mechatronics was bornwith the goal to combine
mechanics and electronics Mechatronicscombines application and system rele-vant functions: actuators, sensors, datahandling and control, into a single func-tional and mechanical unit. The objec-tive of mechatronics is to increase quali-ty and combine it with improved func-tionality and reduced costs. It requires asimultaneous and unprejudiced designprocess, evaluation of all technologies,
materials and processes and a willing-ness to build new production structuresfrom the separated production lines of today.
Figure 5. PC-board of mechatronicmirror. Smart power chip is in center position.
Figure 6. Housing shell formotors and PC-board
www.stm.com
AUTOMOTIVE ELECTRONICS: PART II
possibilities) may not exceed a specificlimit. This limit was set at 1.5 watts toprovide the supplier who has to assem-ble the device in the board with maxi-mum flexibility in his mounting andwiring needs. It also must be consideredthat not all actuators must work simulta-neously. A scenario has therefore beenworked out that shows which actuatorsare given priority under which circum-stances. Whether less important actua-tors are blocked for a short period bytargeted activation of specific functions
is an exclusive decision of the systemdeveloper implemented by means of the software. For this purpose the chipinforms the controller of the current junc-tion temperature. If the thermal reservesare sufficiently high, which is usually thecase, there are no resulting limitations.Should, through particular operatingconditions, a higher power dissipationbriefly occur, this will still have no effectas the thermal impedance of theHIQUAD64 package and is still betterthan 15°C/W after one minute.
The following bar diagram in belowFigure 4, shows the maximum expectedpower dissipation for simultaneous oper-ation of several actuators. It represents,for each actuator:
• which should be activated with priority• which further actuators may also
be activated• which can be shut off for a
specific time
As an example, the turn indicator ischosen. Should this function be activat-ed and the chip temperature is in a limit range, it is no problem to shortlyturn off the mirror heating as its thermaltime constant completely bridges this interruption.
Considerations for chip technologyUD13 is designed in BCD5. What
makes this technology uniquely impor-tant is that the signal section densityreaches a level where it is economicallyfeasible to integrate an 8-bit microcom-puter core and peripheral circuits on asingle smart power chip. A circuit likethis is much more than a micro withsome high power I/Os. Because it isbased on a 40V technology, a BCD5chip can operate directly from a 40Vsupply, deliver several Amperes output
Table 1. Function and loading profile of the mirror actuators.
Figure 4. Maximum expected power dissipation for simultaneous operation ofseveral actuators.
AUTOMOTIVE ELECTRONICS: PART II
www.powersystemsdesign.com 37
lectronic systems must performunder very stringent powerrequirements in automotive
systems. These include load-dump,cold-crank, very low power consump-tion at light loads and low-noise oper-ation. Additionally, footprints mustbe very compact and thermally effi-cient. Linear Technology has devel-oped an entire family of productstargeted specifically to meet thesedemanding requirements.
“Cold Crank” is acondition that occurs whenthe car’s engine issubjected to cold/freezingtemperatures for a periodof time. The engine oil getsvery viscous and requiresthe starter motor to delivermore torque, in turn demanding more currentfrom the battery. This largecurrent load can pull thebattery/primary bus volt-age as low as 4V. Uponignition, it typically returnsto a nominal 13.8V. Theproblem arises when certainsubsystems require aconstant well regulated 5Voutput throughout thiscold-crank condition. These
applications include Engine ControlUnits (ECU), environmental andemergency system microprocessorswhich are critical to the car’s reli-able performance. Traditionally,these requirements were fulfilledby a dual inductor SEPIC (SingleEnded Primary Inductor Coupling)DC/DC converter. The disadvan-tages of a SEPIC topology includea dual inductor configuration
which is both costly and physicallylarge and efficiencies in the low70% range.
Linear Technology’s LT®3433 is ahigh voltage monolithic DC/DCconverter that incorporates twoswitch elements, allowing for aunique topology that accommodatesboth step-up and step-down conver-sion using a single inductor.
The LT3433 uses a 200kHzconstant frequency, currentmode architecture and oper-ates with input voltages from4V to 60V. An internal 1%accurate voltage referenceallows programming of preci-sion output voltages up to 20Vusing an external resistordivider. Burst Mode® operationimproves efficiencies duringlight-load conditions, reduc-ing the device’s quiescentcurrent to 100µA during no-load conditions. A soft-startfeature reduces output over-shoot and inrush currentsduring start-up. Both currentlimit foldback and frequencyfoldback are employed tocontrol inductor currentrunaway during start-up andshort-circuit conditions.
Automotive & Industrial Applications
High Input Voltage Monolithic Switcher Provides Continuous5V from a 4V to 60V Input Using a Single Inductor
High Performance Analog Solutions from Linear Technology
EE
VIN VOUT
CIN D SW
SW
SW
L
(1c) Step-Up/Step-Down (VIN > VOUT or VIN < VOUT)
D
COUT
DN330A F01
VIN VOUT
CIN D
L
(1a) Step-Down (VIN > VOUT)
COUT
VIN VOUT
CIN SW
L
(1b) Step-Up (VIN < VOUT)
D
COUT
Figure 1. The LT3433 Merges the Elements of Step-Up and Step-Down DC/DC Converters
36 Power Systems Design Europe September 2004
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Automotive & Industrial Applications
The LT3433 is available in a 16-pin TSSOP exposed pad packagewhich provides a small footprintand excellent thermal characteris-tics. When the converter inputvoltage is significantly higher thanthe output voltage, the LT3433operates as a modified buckconverter using a boosted-drivehigh side switch. If the converterinput voltage becomes closeenough to the output voltage torequire a duty cycle greater than75% in buck mode, the LT3433automatically enables a secondswitch. This second switch pulls theoutput side of the switched inductorto ground during the “switch on”time, creating a bridged switchingconfiguration.
During bridged switching, theLT3433 merges the elements ofbuck and boost DC/DC converters asshown in Figure 1. In the simplestterms, a buck DC/DC converterswitches the VIN side of the induc-tor, while a boost converterswitches the VOUT side of the induc-tor. Combining the elements of bothtopologies achieves both step-upand step-down functionality usinga single inductor, so voltage
conversion can continue when VIN
approaches or is less than VOUT.
4V to 60V Input to 5V OutputDC/DC Automotive ConverterA 4V to 60V input to 5V output DC/DCconverter is shown in Figure 2. Thisconverter is well suited for 12V auto-motive battery applications, main-taining output voltage regulation withbattery line voltages from 4V cold-crank through 60V load dump. Thethreshold for bridged mode opera-tion is about 8V, so the converterwill normally operate in buck mode.During buck operation, thisconverter can provide load currentsup to 350mA with input voltages upto 60V. Operating with a nominal13.8V input, the LT3433 accommo-dates loads of 400mA and producesefficiencies up to 82% (Figure 3).When the input voltage drops below8V, the converter switches intobridged operation to maintainoutput voltage regulation. Becausethe LT3433 switch current limit isfixed, converter load capability isreduced while operating in bridged
mode. With an input of 4V, theconverter accommodates loads upto 125mA. Not only does theLT3433 converter operate across alarge range of DC input voltages,but it also maintains tight outputregulation during input tran-sients. When subjected to a 1ms13.8V to 4V input transition tosimulate a cold-crank condition,regulation is maintained to 1%with a 125mA load.
ConclusionThe LT3433 simplifies ultrawideinput range DC/DC voltage conver-sion, enabling simple and inexpen-sive solutions to a variety of designproblems. Automatic transitioningbetween buck and bridged modesof operation provides seamlessoutput regulation for wide inputvoltage ranges and input voltagetransients. The use of a small foot-print TSSOP package, a single induc-tor and few external componentsreduces board space requirements,increases efficiency and improvesthermal performance.
OUTPUT CURRENT (mA)
40
EFFI
CIEN
CY (%
)
60
80
90
0.1 10 100 100020
1
70
50
30
VIN = 13.8VBURST
VIN = 13.8VNO BURST
VIN = 4VBURST
VIN = 4VNO BURST
Figure 3. 4V to 60V Input to 5V Conversion Efficiency
VBST
SW_H
VIN
BURST_EN
VC
VFB
SW_L
PWRGND
VOUT
VBIAS
SHDN
SS
SGND
LT3433
0.1µF10V
68k
100k
305k
1nF
330pF(BURST)
(NOBURST)
2.2µF100V
CERAMIC
VIN4V TO 60V
0.01µF
0.1µF10V
100µH
47µF10V
MODE SWITCHVIN H-L: 7.9VVIN L-H: 8.3V
VOUT5V
4V ≤ VIN ≤ 8.5V: 125mA8.5V ≤ VIN ≤ 60V: 350mA
+
Figure 2. 4V to 60V input to 5V DC/DC Converter
he LT3466 is a dual, full func-tion, step-up DC/DC converterspecifically designed to drive upto 20 white LEDs from a wide
input voltage range. Its high efficiency,current mode and fixed frequency oper-ation ensure uniform LED brightness,low noise and maximum battery life.
On-chip schottkydiodes eliminateboth the added costand space require-ments of externaldiodes. Its two inde-pendent convertersare capable of driv-ing asymmetricLED strings (up to10 in series perconverter) from aninput voltage of2.7V to 24V, deliv-
ering efficiencies up to 81%. Its 3mm x3mm DFN package and tiny externalsprovide a very compact footprint forspace-constrained applications.
The LT3466 switching frequencycan be set between 200kHz and 2MHzvia a single resistor, enabling thedesigner to minimize solution footprintand maximize efficiency. Because theLT3466 utilizes a constant frequency
architecture, noise is minimized, elim-inating interference with any onboardRF circuitry. Its 2.7V to 24V input volt-age range enables the device to operatein applications visible from Li-Ion-powered handheld devices to automo-tive backlighting. Also, the LT3466 actsas a constant current source. It deliversthe same current to each white LEDregardless of fluctuations in the LED’sforward voltage drop which vary withtemperature, manufacturing tolerancesand age, ensuring uniform LED bright-ness. Although on the same chip, the
independent step-up converters arecapable of driving asymmetric LEDstrings with independent dimming andshutdown control of each string. Addi-tional features include internal soft-start/inrush current limiting and openLED protection. The combination ofthe LT3466’s high efficiency, versa-tility, low noise and extremely small“total solution” footprint make it idealfor a variety of backlighting applica-tions that require many white LEDs ina tiny form factor.
Dual High Efficiency White LED Drivers with IntegratedSchottkys Drive Up to 20 LEDs from a 3mm x 3mm DFN
Figure 4. Dual Full Function White LED Step-Up Converter with Built-In Schottky Diodes
TT
Low Supply Currents for “Always-On” Systems
ith the adoption of newnavigation, security andalways-on power systems
in automobiles, there is an ever-increasing demand on the batteryeven when the ignition is turned off.Collectively, several hundreds ofmilliamps of supply current required to
maintain standby power to always-onprocessors could completely drain abattery in a matter of weeks. Forexample, after an extended businesstrip, a high-end luxury automobilewould be unable to crank over theengine. Quiescent currents need to bedrastically reduced in order to preserve
battery life without greatly increasingthe size or complexity of the electronicsystems. Until recently, the require-ment of high input voltage capabilityand low quiescent currents weremutually exclusive parameters for aDC/DC converter. A car’s high voltagestep-down converters require 2mA to
WW
HIGHLIGHTS• Drives up to
20 white LEDs from a 3.6V Supply
• Up to 81%Efficiency
• IndependentDimming and Shutdown Control
• 3mm x 3mm DFN-10 Package
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www.powersystemsdesign.com 41
AUTOMOTIVE ELECTRONICS: PART II
Monolithic IC design for lower current applications
The choices that motor control designers have for the power control portion of brush dc motors
have never been better. Brush dc motors are the predominant motor technology in vehicles.
With a high-end vehicle having 60 or more motors, a one-size fits all approach does not work.
By Francoise Vareilhias and Lonne Mays, Freescale
With the ability to integrate moreefficient power MOSFETs withextensive control circuitry with-
in a sophisticated power integrated cir-cuit (IC) process, such as Freescale’sSMARTMOS process, and more effi-cient power packages with sufficientpinouts for a variety of inputs and outputs, today’s IC designers can simplify the motor control system-leveldesign for many different automotiveapplications.
Issues for the control portion includeprotection, diagnostics and communica-tions. Issues for the power switchingdevices include on-resistance, thermalimpedance, and power dissipation. Theright technology for a specific fractionalhorsepower motor depends on themotor, desired features, and the net-work, if appropriate, in which the motor operates.
Multiple Output High-side and Low-side Switches
For lower current applications severalpower MOSFETs and the control circuit-ry can be integrated into a single inte-grated circuit (IC) to control motors and
other loads. For example, the MC33880is an eight-output hardware configurablehigh-side and/or low-side switch with 8-bit serial input control. Two of the out-puts (IN5 and IN6) may be controlleddirectly by a microprocessor for pulsewidth modulated (PWM) applications.The circuit controls various inductiveloads such as motors or solenoids orincandescent loads by directly interfac-ing with a microcontroller. Monitoringand protection features include very low
standby currents, cascade fault report-ing, output-specific diagnostics, andindependent shutdown of output. Figure 1 shows two simplified applica-tion circuits for the 8-output switchwhere the outputs control motors, solenoids and lamps.
The circuit is designed to operatebetween typical automotive voltageextremes of 5.5 V minimum to 24.5 Vmaximum. It has output voltage clamp
Figure 1a. Two low-side switched (single direction) motors could besmall fan motors in a seat cooling and heating distribution system.
Figure 1b. The reversible motor couldbe a power antenna or a headlampwiper or headlamp aiming motor.
40 Power Systems Design Europe September 2004
10mA of supply current. This,combined with other mandatoryalways-on system loads such as secu-rity systems, leakage current from elec-tronically actuated windows and a hostof other “always-on” systems, cancreate a substantial drain on the battery.
The LT®3434 is a 200kHz, 3A(ISW) monolithic buck switching regu-lator that accepts input voltages from3.3V to 60V and can deliver outputcurrents as high as 2.5A to output volt-ages as low as 1.25V. This wide inputrange makes it ideal for automotiveapplications which are subjected to 60Vtransients. Additionally, its Burst Modeoperation reduces “light load” supplycurrent to less than 100µA, making itideal for always-on systems. Currentmode topology is used for fast transientresponse and good loop stability.
The LT3434 is a constantfrequency, current mode buckconverter. It includes an internal clockand two feedback loops that controlthe duty cycle of the power switch. Inaddition to the normal error amplifier,there is a current sense amplifier thatmonitors switch current on a cycle-by-
cycle basis. A switch cycle starts withan oscillator pulse which sets an RSlatch to turn the switch on.
When switch current reaches alevel set by the current comparator,the latch is reset and the switch turnsoff. Output voltage control is obtainedby using the output of the error ampli-fier to set the switch current trip point.This technique means that the erroramplifier commands current to bedelivered to the output rather thanvoltage. A voltage fed system willhave low phase shift up to the reso-nant frequency of the inductor andoutput capacitor (LC), then an abrupt180º shift will occur. The current fedsystem will have 90º phase shift at amuch lower frequency, but will nothave the additional 90º shift until wellbeyond the LC resonant frequency.This makes it much easier tofrequency compensate the feedbackloop and also gives much quickertransient response.
Most of the LT3434 circuitry oper-ates from an internal 2.4V bias line. Thebias regulator normally draws powerfrom the VIN pin. If the BIAS pin is
connected to an external voltagehigher than 3V, bias power will bedrawn from the external source (typi-cally the regulated output voltage)improving efficiency (Figure 5). Highswitch efficiency is attained by usingthe BOOST pin to provide a voltageto the switch driver which is higherthan the input voltage, allowing theswitch to be saturated. This boostedvoltage is generated with an externalcapacitor and diode.
To further optimize efficiency, theLT3434 automatically switches toBurst Mode operation in light loadsituations. In Burst Mode operation, allcircuitry associated with controlling theoutput switch is shut down reducingthe input supply current to less than100µA (Figure 6). The LT3434contains a power good flag with aprogrammable threshold and delaytime. A logic-level low on the SHDN pindisables the LT3434 and reduces inputsupply current to less than 1µA. TheLT3434 provides a high voltage, highcurrent and compact solution with lessthan 100µA quiescent current foralways-on automotive systems.
www.linear.com
ADVERTISEMENTADVERTISEMENT
Note: LT, LTC, and Burst Mode are registeredtrademarks of Linear Technology Corporation.
INPUT VOLTAGE (V)0
0
SUPP
LY C
URRE
NT (µ
A)
50
100
10 20 30 40 50
150
25
75
125
60
VOUT = 3.3VVOUT = 3.3V
Figure 6. LT3434 Supply Current vs Input Voltage
Automotive & Industrial Applications
LOAD CURRENT (mA)
EFFI
CIEN
CY (%
)
100
90
80
70
60
50
40
30
20
10
00.1 10 100 1k 10k1
VIN = 12V
Figure 5. LT3434 Efficiency vs Load Current
www.powersystemsdesign.com 43
the MC33887 is a monolithic H-bridgedesigned for fractional horsepower DC-motor and bi-directional thrust solenoidcontrol. The application circuit in Figure4 shows the monolithic H-bridge control-ling a DC motor, such as a power door
lock. The IC has a sleep-mode featureand incorporates internal control logic,charge pump, gate drive, and four 150-milliohm (typical) MOSFETs. It is ableto control continuous inductive DC loadcurrents of 6.0 A.
Referring to Figure 5, the outputloads can be PWM controlled at fre-quencies up to 10 kHz through theinternal logic and gate drive circuitry.An output current monitoring circuit,similar to the approach shown in Figure3 but fully contained within the chip,provides a proportional (1/375th) feed-back current output for the microcon-troller to monitor the output current andprovide closed-loop control.
The fault status output indicatesundervoltage, overcurrent, andovertemperature conditions. Two inde-pendent inputs provide polarity controlof the two half-bridge totem-pole out-puts for forward and reverse operationfor the motor. An enable (EN) pin isused to place the circuit in a power-con-serving sleep mode reducing the cur-rent draw (in standby) of 20 mA max toless than 50_A.
Other operational features of themonolithic H-bridge include: speed,torque, dynamic breaking, and closed-loop control. The amount of integration
provided by the circuitry requires only 7additional components (6 capacitors and1 resistor) in the typical application.
Packaging for the fully integrated H-bridge and its associated junction to board thermal resistance can be a 20-pin HSOP (5∞C/W), 44-pin QFN(18∞C/W) or 54-pin SO-EP (12∞C/W).
A summary that compares key fea-tures, including packaging aspects, ofthe three different architectures that havebeen presented is shown in Table 1.Fault protection and diagnostics areessential features of these types ofdevices, although how they are imple-mented can vary.
The motors controls that have beenpresented were either directly connectedto the MCU (MC33887 and MC33486)or used a serial peripheral interface(MC33880). Requirements to connect to CAN and LIN buses are becomingcommon in more recent motor controlapplications.
Choose WiselyWhile the choice of motor controls is
ultimately up to the system design engi-neer, based on the analysis that goesinto designing a motor control IC, the ICsupplier can provide assistance thatavoids choosing an IC that may not bethe best choice for a particular applica-tion. Evaluations of the performance ofthe IC during the development and qual-ification phases can involve evaluating avariety of motors and applications. Insome cases, however, the motor controlcircuitry could have been specificallydesigned with only one intended appli-cation and the data sheet simply sug-gests additional applications.
Application concerns such as amountof heatsinking, electromagnetic interfer-ence and availability of a referencedesign are typically discussion pointswith marketing or application engineers.Additional data not found in the datasheet that is available to support a cus-tomer’s design approach is frequently a part of the IC qualification package.These are just of few of the additionaloptions available to make future auto-motive motor control applications easier,quicker and more trouble-free.
www.freescale.com
AUTOMOTIVE ELECTRONICS: PART II
Figure 4. The monolithic H-BridgeMC33887, considerably reduces thenumber of external components toprovide forward and reverse control for a brush dc motor. This simplifiedapplication only shows 2 additionalpassive components.
Figure 5. Internal block diagram of theMC33887, a monolithic H-Bridge witha Sleep Mode feature.
Table 1. Summary of key features.
42 Power Systems Design Europe September 2004
AUTOMOTIVE ELECTRONICS: PART II
of +45 V (typical) for the low-side driveand -20 V (typical) for the high-sidedrive) during inductive switching.
Fault protection circuitry includes:independent overtemperature protec-tion, short circuit detection and currentlimit with automatic retry, internalreverse battery protection on VPWR. In addition, loss of ground or supply voltage will not energize the loads or damage the IC. The 8-Bit (4-pin) seri-al peripheral interface (SPI) that con-nects the 8 output switches to an MCUfor control and fault reporting is 3.3 V/5.0 V compatible.
Each of the eight MOSFETs has antypical on-resistance of 0.55 ohms at25°C and each output is current limited(0.8 A to 2.0 A) to drive incandescentlamps. The circuit draws a maximum 5.0µA standby current at 13 V up to 95°C.Since, the on-resistance of the MOSFETshave an inherent positive temperaturecoefficient, all outputs can be tied togeth-er providing balanced current sharing.
Packaging for the eight-output hardwareconfigurable high-side/low-side switch iseither a 28- or 32-pin plastic packageproviding thermal capability of 94∞C/Wor 70∞C/W, respectively. The 32-pinSOIC has pins 8, 9, 24, and 25 ground-ed for improved thermal performance.
Dual High-side Switch with ExternalLow-side FETs
For higher current applications wherethe dc motor must operate in both for-ward and reverse direction, a four MOS-FET H-bridge with lower on-resistanceis required. One common partitioningscheme integrates only the upper legsof the H-bridge, the high side switches,into the IC with the control circuitry.
For example, the MC33486 integratestwo 15 milliohm N-channel powerMOSFETs with their associated controlcircuitry and additional circuitry for con-trolling the external low-side switches.The dual high side switch for H-bridge(DHSB) is designed to monitor the twolow side switches for H-bridge control ofan automotive DC-motor. It can bedirectly interfaced with a microcontrollerfor control and diagnostic functions, is
PWM capable from DC to 30 KHz andhas a self-adjusted switching speed forminimizing electromagnetic emission.
Each of the 2 high-side switches isprotected against short to ground andload shorts, and has over temperaturedetection with hysteresis. Circuitryincludes a current recopy feature for thehigh-side switches to monitor the loadcurrent. The control circuitry also has anovervoltage detector which turns off thebridge and protects the load in case ofthe battery voltage exceeding 28V. Thelow side control circuitry drives the 2external low-side switches in the H-bridge and provides short circuit protec-tion. This circuitry, in combination withthe high-side protection, fully protectsthe H-bridge from shorted loads, shortsto battery voltage and shorts to ground.
THE DHSB offers a very low quies-cent current in standby mode and cancontrol 10 Amps nominal DC currentand handle up to 35 Amps maximumpeak current. The device is designed tooperate from 8 to 28V but can withstandDC voltages from -0.3V to 40V. It incor-porates overvoltage detection andswitches off when the battery voltageexceeds 28V.
Both the internal high-side switchesand the external low-side switches areprotected from overcurrent and aredesigned for operating junction tempera-tures from - 40∞C to 150∞C. The stand-by mode, implemented by the Wake pin,reduces the standby current to less than
10 _A. A common diagnostic output (St)provides status for both channels.
Packaging for the dual high-sideswitch is a 20-pin HSOP with 5∞C/Wthermal resistance, junction to ambient.This measurement is made with theDHSB mounted on dual-side printed cir-cuit board with 70_m copper thicknessand 10cm2 copper heat sink (2.5 cm2on top side and 7.5 cm2 on the bottomside). The junction-to-case thermalresistance is 2∞C/W.
One of the important design aspectsof integrated dual MOSFETs is the useof a current recopy feature that providesa current mirror with the ratio of 1/3700of the high side output current. Thiseliminates the additional losses that typically occur when a low value seriesresistor is placed in the high currentpath to the motor to determine the cur-rent level. However, as shown in Figure3, it still requires an external resistorconnected to the Cur R pin of the mirrorMOSFET and then tied to an MCU A/Dinput for analog voltage measurement.The Cur R pin is internally clamped(Vclst) to protect the MCU A/D input. If aground shift occurs between the MCUand the DHSS, the amplifier will adaptits output to maintain the same currentcopy. The shift has to be between +/- 1V.
Monolithic H-Bridge All of the H-bridge MOSFETs and the
control circuitry can be integrated into asingle package with a monolithic IC forlower current applications. For example,
Figure 2. A dual high-side switch forautomotive motor control applications,such as the MC33486 uses two exter-nal MOSFETs to complete the H-bridge motor control configuration.
Figure 3. Current recopy in high-sideswitch for current sensing. The exter-nal resistor is not in series with thehigh current path, so it does not con-tribute to power losses.
www.powersystemsdesign.com 4544 Power Systems Design Europe September 2004
the routing for us, using the latest map-ping information and a knowledge ofroad usage according to time of day,allowing users access to the most opti-mal route. Such a hardware platform isshown in Figure 2. Here we can seethat, rather than integrating a GSM mod-ule to provide the required data link tothe internet, and the associated prob-lems of trying to implement a way of theuser using a SIM card for call billing, aBluetooth interface has been addedusing the LMX5252 radio. Bluetooth pro-vides GPS Navigation System develop-ers with the most cost effective, shortesttime to market and most interoperablesolution to this low cost GPS System.
By making use of the Dial-UpNetworking Profile (DUNP) of Bluetooth,a GPS Navigation System can use anyavailable local Bluetooth enabled mobilephone to access internet based trafficinformation. The web-based traffic infor-mation could be provided through part-nerships with automobile associationsthat already provide such information
(e.g. ADAC in Germany) or throughweb-sites that are created specificallyfor the purpose by the hardware manu-facturer (see Figure 3). Due to the guar-anteed interoperability of the Bluetoothprotocol and profiles, the GPS systemdeveloper can leave it up to the endconsumer to choose how the navigationsystem will access the internet basedtraffic information by choosing an appro-priate Bluetooth enabled mobile phoneand GSM service provider.
National Semiconductors CP3000family of Connectivity Processors formthe perfect platform to Bluetooth enableany current GPS system in such a man-ner, be it embedded into a car dashboard,or a handheld system. These devicesalso provide many additional connectivi-ty interfaces that give additional flexibili-ty or provide a means to develop the prod-uct further with time. In addition the largeaddressing capability of the processorcan provide ample off-chip memory forimmediate storage of downloaded dataand traffic information databases.
The CP3000 Connectivity Processorsare driven by the powerful, third genera-tion CR16C CompactRISC processorcore – a 16-bit RISC like processor.Because of its delicate blend of RISCinstructions, keeping code size small,and CISC type instructions, allowingnon-interruptible bit manipulation,push/pop and load/store instructions,the CR16C is quite capable of support-ing the Bluetooth interface, includingprofiles, and handling complex applica-tions in small amounts of memory. Theability to store and retrieve up to 8 inter-nal core registers to and from the stackquickly using a single instruction makesRTOS’s easier to port, and ensures fastand effective context switches. Thethree-stage pipeline performs the fetch,decode and execution of instructions,allowing a peak throughput of oneinstruction per clock cycle. Despitebeing a 16-bit architecture, with mostly16-bit general-purpose registers, it canalso be seen that the internal data pathof the core is 32 bits wide. This allows32-bit data to be loaded into the four
www.powersystemsdesign.com 45
AUTOMOTIVE ELECTRONICS: PART II AUTOMOTIVE ELECTRONICS: PART II
Only optimised power consumption together with power management on chip and systems level
allows applications like this one. If we play in the automotive world the luxury accessories can
only be efficient if they don’t reduce the economic aspects.
By Stuart Cording, National Semiconductor
Bringing low cost navigation to the motorist
If given the choice, I am sure thateveryone would take the option ofhaving a GPS navigation system in
their vehicle. The amount of time whentravelling that can be saved, and thequantity of frustration when lost that canbe relieved can be considered too valu-able to be turned down. But, unfortu-nately, the price tag that this level ofcomfort commands is just too much formost people. Even the latest range ofsoftware and GPS add-ons for the vari-ous PDA platforms have still not broughtquality navigation aids to the masses.So for now, at least, we must rely on our sense of direction, the support of afellow passenger with whatever mapsare to hand and the quality of the localsigns to navigate our way through the unknown.
If we look at the design of a typicalbuilt-in or aftermarket GPS NavigationSystem (Figure 1), we can see the build-ing blocks are made up from severalcostly components. Firstly there is theprocessor, which is typically of a 32-bittype allowing the complex routing algo-rithms to be calculated quickly and effi-ciently to provide a quality user experi-ence. Next comes a colour display toshows the map of the current location,and possibly a touch screen for userinput. A GPS module is of course amust, as is the storage medium for hold-ing the database of maps, locations andpoints of interest. One large cost whichis not shown here is the license fee forthe map itself which is the reason whynew CD-ROMs for these systems are
so costly, and why most motorists do notbother to keep their system up to date.The navigation system in it’s currentform has more or less remained thesame since it was first designed, butwith data being available readily fromthe internet these days, a GSM modulewould also provide the perfect way toenhance the features of the systems toprovide accurate traffic information,points-of-interest, hotel booking featuresand more. Unfortunately, the cost ofdoing so remains prohibitive
Ideally, if one of these systems is builtinto the car, the user could just use theirown mobile phone fitted into a cradle toprovide that data link. Unfortunately,adding a cradle for a GSM mobile phoneis also too complicated for the massmarket due to the large number of differ-ent and ever changing connectors usedby the different phone manufacturers.The RDS system used by car radios can
provide traffic data for use by navigationsystems, but these are always limited tosystems that are embedded into thecars dashboard.
In order to bring navigation systems tothe broad market, both as an optionwhen purchasing a new car and as aproduct for the aftermarket, the cost ofthe system needs to be brought downconsiderably. It needs to based on alow-cost microcontroller, whilst bringingthe user a broad range of valuable serv-ices such as traffic-avoidance routingand traffic-flow updates during the jour-ney. The display of a colour map canremoved, as it is not really required, andreplaced with high quality verbal direc-tion commands and text based direc-tions from a simple and value for moneymonochrome type display. And we canalso do away with the local CD-ROM orFlash memory map information andinstead use a remote server to calculate
Figure1. Aftermarket GPS Navigation System
www.powersystemsdesign.com 47
AUTOMOTIVE ELECTRONICS: PART II
Wide range of features requested fromswitching regulators
Depending on where the electronic system operates on the automotive power bus, it is frequently
required to perform under very stringent power requirements. These include load-dump,
cold-crank, very low power consumption at light loads, and low-noise operation. Additionally,
solution footprints are generally required to be very compact and thermally efficient.
By Tony Armstrong, Linear Technology Corporation
Over the past decade, the elec-tronics content in automobileshas made quantum leaps in
both the quantities and sophistication ofelectronic control, telematics and enter-tainment systems. With the recent intro-duction of electric and electric/hybridvehicles, the electronics content extendseven further into propulsion systems. On one end of the automotive spectrum,many historically mechanical systemssuch as throttle control, braking, andsuspension control are now being bothcontrolled and optimized by electronicsystems. On the other end, entertain-ment and wireless navigation are fastbecoming standard equipment on non-luxury automobiles.
Wide operating voltage requirementscoupled with large transient voltagesand large temperature excursions com-bine to make life tough on electronicsystems. What’s more, the performancerequirements continue to become eventougher. Multiple supply voltages arerequired for different portions of the sys-tem. A typical Navigation system canhave six or more different suppliesincluding 8V, 5V, 3.3V, 2.5V, 1.8V, and1.5V. At the same time, as the numberof components increases, the spaceavailable continues to shrink. Therefore,efficiency becomes more criticalbecause of the space limitations and
temperature requirements. At low outputvoltages and even with moderate cur-rent levels, above a few hundred milli-amps, it is no longer practical to simplyuse a linear regulator to generate thesesystem voltages. As a result, over thelast several years, primarily due to ther-mal constraints, switching regulatorshave been replacing linear regulators.The benefits of a switcher, including theincreased efficiency and smaller foot-print, outweigh the additional complexityand EMI considerations.
Virtually all luxury automobiles comewith in-dash audio, visual and naviga-tional systems, along with the traditionalinstrument panel. All of these systemsneed some kind of backlighting to allowfor readability in all kinds of ambientlight conditions. White LEDs are nowcommonly used to provide backlighting.In these applications, the white LEDsmust be powered by a constant currentto guarantee consistent light intensityand uniform brightness. Figure 1 showsthe LT3466 powering 50 (two banks of25) white LEDs from a 12V input supply.The circuit is configured as a voltagetripler to produce output voltages inexcess of 90V. This allows a string of 25 LEDs to be connected at each out-put, resulting in constant current anduniform brightness.
The device is configured to operate at a 2MHz switching frequency by thechoice of the 20.5kW resistor. Thisensures that the radiated switchingnoise falls outside the AM radio band.High switching frequency also allows the use of low-profile inductors and sur-face mount capacitors. Furthermore, inthis application the LT3466 delivers2.4W output power with 83% efficiency.The thermally enhanced 3mm x 3mmDFN packaging (with exposed pad) oftheLT3466 enables it to drive as manyas 50 white LEDs from a 12V input sup-ply. For optimum performance the induc-tors can be powered directly from thebattery, whereas the LT3466 should bedriven from an existing 3.3V rail.
The LT3466 has two independent, butidentical, step-up converters capable ofdriving asymmetrical LED strings. Thestep-up converters are designed to drivethe series connected LEDs with a con-stant current, thus ensuring uniformbrightness and eliminating the need forballast resistors. It also incorporatesinternal 44V power switches andSchottky diodes. Switch current limit isguaranteed to be greater than 320mAover the full operating temperaturerange. A low, 200mV, high accuracy(±4%) reference voltage is provided toprogram the LED current.
46 Power Systems Design Europe September 2004
general-purpose core registers that are32 bits wide, enhancing the cores per-formance when using relocatable code.With the efficient Index Addressingmode, a mixture of memory types canbe used to expand the generous256kbytes of on-chip flash memory and10kbytes of on-chip SRAM. The on-chipflash memory also supports single cycleread accesses at system clock frequen-cies of up to 24MHz.
The CAN interface of the CP3000communications processor is suitable
for navigation systems built into thedashboard of a car. This would allowautomotive manufacturers to integratethe GPS system through the CP3BTonto a CAN bus to share data and issue and accept control requests.Additionally, the system could use dash-board displays and control buttonsalready within the vehicle as its human-machine interface (HMI). The alternativeinterface for aftermarket GPS systems is the USB interface. This would giveconsumers the flexibility to connect theGPS system to a laptop or desktop PC,
which commonly have USB but noBluetooth interface at present, whilststill being able to make use of theBluetooth capability of their mobilephone for traffic information whilst onthe move. The audio from the systemcould also be rerouted through to theaudio system that already resides in thevehicle, temporarily muting the radio asit does so.
Because of Bluetooth’s high level offlexibility, support of many different con-nections with many types of electronicproducts, and the guaranteed interoper-ability of the protocol, it has to be theinterface of choice to extend the capabil-ities of navigation systems. The CP3000family of connectivity processors isavailable to make that choice easier.
Figure 2. Complex Info input. Figure 3. The full Advantage ofSystem Design.
www.national.com/appomfp/cp3000
AUTOMOTIVE ELECTRONICS: PART II
www.powersystemsdesign.com 49
NEW PRODUCTS
48 Power Systems Design Europe September 2004
The step-up converters use a currentmode topology to provide excellent lineand load transient response. Internalfeedback loop compensation of the LT3466allows the use of small ceramic capaci-tors on the output. The built-in over-volt-age protection circuit clamps the outputto either converter to 42V if the LED stringconnected to that output fails open-cir-cuited. Internal soft start is provided for
each step-up converter during start-up.
The switching frequency of the LT3466can be programmed over a 200kHz to2MHz range by means of a single resistorfrom the RT pin to ground. Its 2.7V to 24Vinput voltage range makes it ideal for awide range of applications. The devicefeatures independent shutdown anddimming control of two LED string. The
current in each LED string can be shutoff by pulling the respective control(CTRL1 or CTRL2) pin voltage below50mV. Dimming of each LED string isachieved by applying a DC voltage toits respective control pin. When bothCTRL1 and CTRL2 pin voltages arepulled below 50mV, the devices enterstotal shutdown.
The LT3466 is a dual white LED driverwith integrated switches, Schottky diodesand a space saving 3mm x 3mm DFNpackage. The wide operating voltagerange and high frequency capability ofthe LT3466 enables it to meet the back-lighting needs for automotive instrumentpanels and car radio displays. Features
like the internal soft start, open LED pro-tection and internal loop compensationreduce the number of external compo-nents, thus reducing the overall cost andsize of the white LED driver circuit.
www.linear.com
Figure 1. 50 white LEDs powered by 12V input using low profile surface-mountcomponents.
AUTOMOTIVE ELECTRONICS: PART II
Artesyn Technologies has launchedtwo new 5V single output eighth-brickDC/DC converters which provide industry-leading conversion efficiencies
of 92%. The new converters are avail-able with current ratings of 10 and 15A now, and 20A in the near future,enabling designers to choose the most cost-effective model for their par-ticular application.
Both converters feature a wide inputvoltage range of 36 to 75VDC and generate a single 5V isolated output,adjustable over the range 4 to 5.5V via asingle external resistor. The convertersfeature remote sense and remote on/offfacilities as standard, and have a typicalstart-up time of 10ms when driving aresistive load. Synchronous rectificationand advanced processor control of bothprimary and secondary-side circuitrymaximise efficiency and transientresponse.
Artesyn’s 5V eighth-brick convertersare designed for operation over anambient temperature range of -40 to+85_C without a heatsink. Their ultralow profile construction minimises air-
flow disruption and makes them suitablefor both convection cooled and forcedair environments. The converters fea-ture under-voltage lockout, as well asnon-latching over-voltage protection,and are also protected against short-cir-cuit and over-temperature conditions,with automatic recovery. The converterscarry a full set of international safetyapprovals, including EN60950 VDE and UL/cUL60950.
5V Eighth-Brick DC/DC Converters at 92%
www.artesyn.com
www.powersystemsdesign.com 51
Advanced PowerConversion PLCannounces a furtherenhancement to its
broad range of DC-DC converters with thenew APC-PEN series.
Providing 2.5 W to 6 W of output powerin a low profile DIP24 case, the rangeoffers a working temperature between–40°C and +85°C without derating.
Offered in single or dual output versions,
inputs include: 9-18, 18-36, and 36-72 VDC wide input 2:1. For applicationsrequiring a very wide operating voltagerange wide input 4:1 versions are avail-able with 9-36 and 18-72 VDC.
A very compact and versatile packagethe APC-PEN series is similar to theAPC-TG range but modified to matchindustry common pinning. The converterscan be supplied in either non conductiveblack plastic or Nickel Coated Copper
and efficiency is up to 81%. Additionalfeatures of the range include six sidedshielding, isolation of 1500 VDC and themodules are short circuit protected withcontinuous, automatic restart. Outputsoptions include: 3.3, 5, 9, 12, 15 and 18V DC single outputs as well as dual out-puts with : +/- 3.3, 5, 9, 12, 15 and 18 V.
Off-Line IC Family for Efficient Power Supplies 2.25MHz Dual 800mASynchronous Step-Down DC/DC ConverterPower Integrations announced today
the expansion of TinySwitch-II, the com-pany’s widely used low power family ofoff-line switcher ICs. The two newdevice family members, TNY263 andTNY265, extend the cost effectivenessof the highly integrated, energy efficient,low power IC family.
The TNY263 offers a lower-cost,lower power solution compared toTNY264 for universal input adapters upto 3.7 W or up to 7.5 W for 230 V inputopen frame designs. The TNY265 pro-
vides a cost optimum solution for powerlevels that fall in between the capabili-ties of existing TNY264 and TNY266 byaddressing universal input adapters upto 5.5 W or up to 11 W for 230 V inputopen frame supplies.
The TinySwitch-II family integrates a700 V Power MOSFET, an oscillatorwith simple on/off control, and currentlimit and thermal protection circuitry ontoa single CMOS chip. Other built-in fea-tures include auto-restart for short circuitand open loop fault protection, frequency
jittering for low EMI filtering cost, pro-grammable line under-voltage detection,and circuitry to eliminate audible trans-former noise. Key parameters aredesigned with very tight tolerances andnegligible temperature variation. Theinternal switching frequency of 132 kHzreduces transformer size, allowing theuse of low cost EF12.6 or EE13 cores.
www.powerint.com/greenroom
50 Power Systems Design Europe September 2004
NEW PRODUCTS
www.powerint.com
Power MOSFETModulesAdvanced Power Technology
Europe announced the addition of1000V and 1200V MOSFET mod-ules to the existing product rangein SP4 and SP6 packages.
These modules are offered insingle switch, Buck, Boost, Dualcommon source, phase leg andfull bridge configurations. Currentratings range from 13A to 160Amps.
Single switch, phase leg and full bridge configurations utilizeMOSFETs with high speed intrinsic diodes (FREDFET) forimproved diode recovery charac-teristics and better dV/dt capabili-ty. High current single switch mod-ules, with and without a combina-tion of series and parallel diodes,utilize AlN substrates for best thermal characteristics.
The low profile SP4 and SP6modules exhibit minimum internalparasitic resistance and induc-tance offering high frequencyoperation capability. The use ofthe latest generation PowerMOS 71000V and 1200V MOSFETs andFREDFETs allows operating inhard switching mode in the rangeof 100 kHz to 200 kHz.
Linear Technologyannounces theLTC3407-2, a dualoutput, high effi-ciency, 2.25 MHzsynchronous buck
regulator that delivers up to 800mA ofcontinuous output current from two sep-arate channels. Using a constant fre-quency and current mode architecture,the LTC3407-2 operates from an inputvoltage range of 2.5V to 5.5V making itideal for single cell Li-Ion, multi-cellalkaline or NiMH applications. TheLTC3407-2 can generate two inde-pendent output voltages as low as0.6V, enabling it to power the latest
generation of low voltage DSPs andmicrocontrollers. Its 2.25 MHz switchingfrequency of keeps switching noise outof critical AM and xDSL frequencybands and allows the use of tiny, lowcost ceramic capacitors and inductorsless than 1.2mm in height. TheLTC3407-2 is the most compact syn-chronous step-down solution availablefor dual output voltage rails, with its tinyexternals and MSOP-10 and 3mm x3mm DFN packages.
The LTC3407-2 uses internal switcheswith an RDS(ON) of only 0.35 Ohms todeliver efficiencies as high as 95%. Itutilizes low dropout 100% duty cycleoperation for output voltages up to VIN,further extending battery run-time. Noload quiescent current is only 40uA(both channels) and <1uA in shutdown,ensuring optimal battery life.
www.linear.com
www.linear.com
DIP24 DC-DC Converter
www.advancedpower.com
NEW PRODUCTS
52 Power Systems Design Europe September 2004
NEW PRODUCTS
Fairchildannounces itsadvanced-per-formancePowerTrench(r)MOSFETprocess tech-nology that
yields exceptionally low values for MillerCharge (Qgd), RDS(on), total gatecharge (Qg), and improves gate-draincharge to gate-source charge (Qgd:Qgs)ratio-enhancements that result in superi-or switching performance and thermalefficiencies when used in synchronousbuck applications. The benefits of lowQgd are decreased switching losses
and reduced “dead time” for improvedregulation. A favorable Qgd:Qgs ratiooffers immunity against false gate trig-gering that result in shoot-through cur-rents between switching MOSFETswhen employed as a synchronous rectifier.Low RDS(on) is critical in minimizingconduction losses and low Qg reducesthe power consumed to turn the MOSFETon and off each cycle. Two 30V MOSFETsfrom Fairchild, the FDS6294 andFDS7288N3, exhibit the benefits of thisimproved fast-switching technology.
With its very low Qgd, the new FDS6294provides excellent performance in high-frequency, narrow duty cycle switchingapplications. The extremely low Miller
Charge (Qgd) value of 3nC (typical) ofthe FDS6294 minimizes this transitiontime, and in conjunction with a lowRDS(on) of 11.3m??max, allows thedevice to offer superior performance to existing solutions. The FDS6294 isavailable in an SO-8 package. For more information about these prod-ucts go to:• http://www.fairchildsemi.com/pf/FD/
FDS6294.html• http://www.fairchildsemi.com/pf/FD/
FDS7288N3.html.
www.fairchildsemi.com
MOSFET Technology Reduces Miller Charge by 35-40%
Companies in this issueCompany Page Company Page Company Page
ABB Lyon . . . . . . . . . . . . . . . . . . . . . . .49ABB Switzerland . . . . . . . . . . . . . . . . . . .1Allegro MicroSystems . . . . . . . . . . . . . . .1Analog Devices . . . . . . . . . . . . . . . . . . . .1Anagenesis . . . . . . . . . . . . . . . . . . . . . . .1Ansoft . . . . . . . . . . . . . . . . . . . . . . . . . .11Ansoft . . . . . . . . . . . . . . . . . . . . . . . . . .1,4APEC . . . . . . . . . . . . . . . . . . . . . . . . . . .31Advanced Power Technology . . . . . . .24Asvanced Power Technology . . . . . . . .51Artesyn Technologies . . . . . . . . . . . . .1,49CT-Concept Technology . . . . . . . . . . .13Danfoss . . . . . . . . . . . . . . . . . . . . . . . .48eupec . . . . . . . . . . . . . . . . . . . . . . . . . . .9eupec . . . . . . . . . . . . . . . . . . . . . . . . . . . .1Electronica . . . . . . . . . . . . . . . . . . . . . .C3Fairchild . . . . . . . . . . . . . . . . . . . . . . . .C2
Fairchild . . . . . . . . . . . . . . . . . . .1,4,12,52Freescale . . . . . . . . . . . . . . . . . . . . . . . .41Hitachi . . . . . . . . . . . . . . . . . . . . . . .35,51International Rectifier . . . . . . . . . . . . .C4International Rectifier . . . . . . . . . . . . .1,27Intersil . . . . . . . . . . . . . . . . . . . . . . . . . . .5Intersil . . . . . . . . . . . . . . . . . . . . . . . . . .1,4Intusoft . . . . . . . . . . . . . . . . . . . . . . . . . .52iSuppli . . . . . . . . . . . . . . . . . . . . . . . . . .22LEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3Linear Technology . . . .7,26,37,38,39,40Linear Technology . . . . . . . . . . . . .1,47,51Mircel . . . . . . . . . . . . . . . . . . . . . . . . . .21Microsemi . . . . . . . . . . . . . . . . . . . . . . .29Mitsubishi . . . . . . . . . . . . . . . . . . . . . . .23National Semiconductor . . . . . . . .1,10,44Ohmite . . . . . . . . . . . . . . . . . . . . . . . . .50
Ohmite . . . . . . . . . . . . . . . . . . . . . . . . . . .1On Semiconductor . . . . . . . . . . . . . . . . . .1Power Systems Design Europe . . . . .36Power Integrations . . . . . . . . . . . . . . .45Power Integrations . . . . . . . . . . . . . . . . .50Raychem Circuit Protection, Unit of Tyco Electronics . . . . . . . . . . . . . . . . .46Renesas . . . . . . . . . . . . . . . . . . . . . . . . .6Semikron . . . . . . . . . . . . . . . . . . . . . . .1,6SynQor . . . . . . . . . . . . . . . . . . . . . . . . . .1STMicroelectronics . . . . . . . . . . . . . . . .32Tektronix . . . . . . . . . . . . . . . . . . . . . . . . .6Texas Instruments . . . . . . . . . . . . . . . .15Texas Instruments . . . . . . . . . . . . . . . . . .4Tyco Electronics . . . . . . . . . . . . . . . . . . .1Westcode . . . . . . . . . . . . . . . . . . . . . . . . .4Zetex . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Intusoft announced the release of itssecond-generation IBIS-to-SPICE modelconversion software. The enhanced pro-gram (IBIS2SPICE Converter) offersmore power and ease of use thanIntusoft’s former version released in1998. The new version supports all 14IBIS model types, and converts IBISmodels up to and including version 3.2.
The converter now uses an updatedmodeling template, which producesSPICE models that exhibit remarkableaccuracy with Intusoft’s IsSpice4 simula-tion kernel. SPICE models are generat-
ed for Input, Output, I/O, 3-state, Open-Source, Open-Drain and other I/O struc-tures. Further, the SPICE models can beeasily added to the part browser insideIntusoft’s ICAP/4 “SpiceNet” designentry system, an integral part of the ana-log, mixed-signal and mixed-systemdesign automation tool suite.
IBIS2SPICE Converter will be includ-ed free of charge with the following soft-ware packages: Test Designer, ICAP/4Professional, ICAP/4Windows PowerDeluxe, ICAP/4Windows RF Deluxe andICAP/4Windows, in Intusoft’s upcoming
ICAP/4 software release in Q3 of 2004.For Intusoft customers currently onmaintenance with any of the abovepackages, IBIS2SPICE Converter canbe downloaded at no charge from thetechnical support page at:http://www.intusoft.com/support.htm.For all others, a former version is avail-able at no cost from: http://www.intusoft.com/utilities.htm.
Second–Generation IBIS2SPICE Converter
www.intusoft.com
