Howled Tvs Work

8/13/2019 Howled Tvs Work

http://slidepdf.com/reader/full/howled-tvs-work 1/53

AC-DC LCD TV Power Architecture

andLED Backlight



LCD TV Power Architecture and LED Backlight

• LCD-TV Market

– Power Reduction Trend

– Edge LED LCD TV Backlight

• 26” to 42” H-V LIPS Reference Design

• 46/47” Power Reference (PSU) for any Backlight solution – Interleaved Frequency Clamp CrM PFC with NCP1631

– Quasi Resonance Valley lock out Flyback Converter with NCP1379 – ECO Standby SMPS Solution with NCP1053A

• 46/47” Backlight solution

– LIPS Inverter – Edge LED Driver

• Conclusion



LCD-TV Shipments by Size

Source: Displaysearch 2Q 09



Power Reduction Trend

• Regulatory reduce powerconsumption in active andstandby mode

• New technologies focusedon improving efficiency

Source: Sharp

• Proposed ENERGYSTAR TV regulations(V4.0) will lower average power targets

Power consumption reduction ~ - 50% over 2 years



Proposed ENERGY STAR rev4.0 Standards

Target Effective Date: May 2010

Very few LCD-TV pass

proposed new standard,

most are Samsung LED



LCD-TV LED Backlighting

LED TVs is forecast to grow to 20-32% (~64 M#) by 2012

Source: DisplaySearch July 2009



Comparison of LED LCD TV Backlight Options

• Thermal limitations

• High system cost due to number

of LEDs and # of Drivers

• Picture artifacts

• System Noise & EMI

• Using lots of external components

(Inductor, capacitor, diode)Concerns

Boost or Buck plus Multi-channel

linear

High voltage Boost, buck, linear with Vf

adjustment

LED

driver

Direct-type LED BLUEdge-lit LED BLU

Merit

• Deep blacks, better contrast• Local dimming

• Scanning for higher frame rate

• Low power consumption

• Complex signal processing

• High Power Efficiency• Good system reliability independent

LEDs performance.

• Cost down of system

• Slim LCD TV

Edge LED > 90% ?



Power Architectures Remain Varied

PFCCRM

Interleave FCCrM

CCM

70 - 400+ W

Signal Power Flyback

Resonant HB

30 – 80 W

Backlight Power

Flyback / Resonant HB24V / 150V+ for LED

HV-LIPS for CCFL / EEFL

50 – 300 W

Traditional 24 V Backlight and HV-LIPS approach

Thin TV design impacts solutions choices as well

ECO Standby< 5 W



32” HV-LIPS Reference Design

• For 32” (highest volume size) with possible extension to 26/42”

– Available since March 2009

– For CCFL ( >> 95% of backlight) with possible extension to EEFL

– Single PCB with LCD and Inverter Power Supply

• Very Cost effective solution

– No extra Standby SMPS

– Straightforward CrM PFC

• Key ON Semiconductor ICs

– NCP1607 as CrM PFC controller

– NCP1351 or NCP1219 as Flyback with low power standby mode

• LX6503 Microsemi Backlight controller

– Full Bridge High Voltage Inverter without High Side Driver (discrete circuit)

– Jin balance solution



32” HV-LIPS LCD TV Block Diagram



HV-LIPS LCD TV Complete Solution

Green Point Reference design documentation:http://www.ONSemiconductor.com/pub_link/Collateral/TND3

60-D.PDF

12 CCFL175 mm x 330 mm x 25 mm

All-in-one board with current balancer



46/47” Power Reference (PSU)

•Higher power LCD-TVs from 40/42” to 52” /55”

•Project focusing on power stage only – ECO standby “ OFF mode”

– Interleaved frequency clamp CrM PFC

– Up to 70 W Flyback – Up to 200 W for backlight

•Low profi le design – 1st phase: < 13 mm

– 2nd phase: < 8 mm



46” LCD TV Power Block Diagram



46” LCD TV Power Solution Unit (PSU)

Low Profile design < 13 mm / 17.5 mm total



46” LCD TV PFC Solution

•Up to 300 W Interleaved Frequency Clamp CrM

PFC – Better EMI and EMC

– Lower Irms for output C – Better for SLIM design

– Standard parts (= 32” CrM)

•New controller NCP1631

•Easy SLIM narrow range version

Interleaved FCCrM PFC for > 200 W & SLIM design



PFC Summary





46” LCD TV QR Flyback Solution

•Flyback converter – Up to 70 W max

– Up to 3 output with 4 A Max

•Quasi Resonance Flyback Converter – Reduced EMI

– Best safety behaviors

•New NCP1379 controller – Valley-lockout system

– Variable frequency mode for ultra low power mode – Over current protection with auto recovery internal

timer



46” LCD TV PWM Fixed F Flyback Solution

•PWM Fixed Frequency Flyback converter – 50 kHz Fixed frequency

– Allow natural CCM

•New NCP1252 controller – Adjustable switching frequency with skip mode

– Adjustable soft start

– Over current protection with internal timer

• Alternative solution to previous QR mode – Both designs

• on the same PCB

• with the same switching frequency

• with the same key parts

QR Valley lock-out or PWM Flyback SMPS up to 70 W



46” LCD TV Flyback Schematic

2_5VREF

D207

MBRF20L80CTGto220

1 2

3

Flyback power to

Signal processing

and Audio board

R228 1K

Backlight

controller

supply to

Backlight

board

D215

MMSD4148

R23810K

R203 33k

R2210.47R 2W CN403

Gnd_Lug

1

+

C206

470u 16V

P

N

D216

MMSD4148

PC101B

SFH817A

4

3

CN2024324-03S

123

R2121K

L201 10uH1 2

+

C219

470u 16V

P

N R2192K2

+

C216

10u 50V

+

C209470u 16V

P

N

L202 10uH1 2

R209 100

R231 16K2

+

C207

470u 16V

P

N

*

*

*

*

*

T200750875731

3

7

1

5

612

11

8

109

R2231K

R226 1K

C218100p 1KV

D206MMSD4148

C212

220p C215

100n

D203

MMSD4148 NCP1379IC200

VCC 6

ZCD1

CT 8

FB2

DRV 5

GND4

CS3

BO 7

R255

10M 2W

R2422K2

D205

BAV21

C225

Y 1nF

+

C205

470u 16V

P

N

D211MMSD4148

R22047k

R214

10k

R205

1K

ZD200

MMSZ15T1

+

C221

470u 16V

P

N

Q201BC858ALT1

3

1

2

D209

MMSD4148R218

3K3

Q207BC858ALT1

3

1

2

+

C224470u 16V

P

N

Q205BC858ALT1

3

1

2

PC101A

SFH817A

2

1

CN2014324-11S

123456789

1011

ZD201MMSZ6V8T1

Q202

MJD200DPAK

D221

MMSD4148

D210

MBRF20L80CTG

to220

12

3

+

C232470u 16V

P

N

R241

2K2

R208

2K2

R232 6K19

R215220

+C21747u 25V

R23710K

+

C220

470u 16V

P

N

R207 4R7

R2111K

D219

MMSD4148

D208MMSD4148

D217

MMSD4148

C20010n 500V

C21068p

R2498K2

D201

1N4937do41d

R25133K 2W

R206

470k

R2101K

Q203STP5NK70ZFP

C211

1n

+

C222

470u 16V

P

N

R213

470

R2221K

C213

330p

Q204BC808-25LT1

3

1

2

+

C208

470u 16V

P

N

C230

470nF

IC201

TL431BCLPRA

3

2

1

C214

100nR216220

R25233K 2W

R2332K49

R2271K

R2364K7

R217 27

VS2

VS1CS

CS

PFC_OUT

PFC-OK

VCC4

V1

Regulation

V2

VS2

Regulation

VS2

VS1

VS1

VS1

VS2

V2

Regulation

V1

VS-Stby

VCC3

2_5VREF



46” LCD TV QR Flyback Waveforms

• QR mode with valley lock-out

– With valley lock-out for low P

– With lower frequency by P Max

• Top Trace

– Vin = 400 Vdc Pout = 34 W

– 1.75 A at 42.7 kHz

– V max = 572 V

• Bottom Trace

– Vin = 400 Vdc Pout = 70 W

– 2.62 A at 39 kHz

– V max = 618 V

Valley lock-out is a Key improvement of QR mode



ECO Standby SMPS Solution (1)

•Dedicated 5W ECO Power Standby SMPS

– Pin < 90 mW for Pout = 40 mW @ 230 Vac

– Integrated High Voltage switcher NCP1053A (400 mA/ 40 kHz Max)

• Hysteretic mode improves

• Low frequency mode allows DCM

• Limited current reduces possible noise issues

Hysteretic, Low Freq & DCM for ECO Standby SMPS



ECO Standby SMPS Solution (2)

•Standby relay – Disconnect all “ parasitic” standby load (~100-150

mW @ 230 Vac)

– Directly controlled by TV µP

•Optional ECO “ ON / OFF switch” – Low cost 2A / 10V non-isolated switch

– OFF mode: Pin < 20 mW by no load @ 230 Vac

ECO switch provides “ ON/OFF” without Mains switch



20

30

40

50

60

70

80

0.03 0.04 0.05 0.10 0.25 0.50 1.00 1.50 2.00 4.00 5.00

Output Power (W)

E f f i c i e n c y ( %

)

Efficiency / 230V

Efficiency / 120V

ECO Standby SMPS efficiency

OFF mode / no load: Pin < 20 mW @ 230 Vac (15 @ 120 Vac)

Standby / 40 mW Out: Pin < 90 mW @ 230 Vac (86 @ 120 Vac)



ECO Standby SMPS Waveforms

• Drain Voltage and Current ofNCP1053A Switcher

– 200 V/div & 200 mA/div

• For 5 V & 1 A = 5 W Output

• Left: Hysteretic Burst mode

– (100 µs/div)

• Right: Detailed cycle

– (4 µs/div)

• Top Trace: 90 Vac

• Middle Trace: 230 Vac

• Bottom Trace: 264 Vac



ECO Standby SMPS Schematic

VS-Stby

VCC2

VCC1

PC100A

C10710nF

SFH817A

2

1

R103 8.2K

R1101K

R101

1K

Q103

BC848ALT1

CN1014324-05S

12345

Q100

BC858ALT1 3

1

2

R120 0

Q101 BC808-25LT13

1

2R10410K

+

C104

10u 25 V

R11922K

J100

INSTALL 1

2

D100

MBR360

NCP1053P44GIC100

VCC1 GND 8

Control in2

Power Drain 5

NC4

GND3

GND 7

R118470

IC101TLV431ASN1

3

2

1

R115 1K

R1142K2

D104

MMSD4148

1.25VREF

R116 1K

R113 4K7

PC001B

SFH817A

4

3

R100100K 1/4W

D102

BAV21

ZD101 MMSZ5V1T1

R11110K

D108 MMSD4148

CN1004324-02S

12

D105

MMSD4148

R10910K

C100220p 400V

L100

10uH1 2

R102

30K

R1174.7K

R1074.7K

PC100B

SFH817A

4

3

D110 MMSD4148

ZD102 MMSZ15T1

D106

MMSD4148

R10510K

T100750871014

7

83

14

5 6

9

R106470

+ C102

470µ 16V

P

N

R1121K

R1084.7K

+ C10347µ 25V

P

N

+

C105

47u 25 V

D101 1N4937

D103MMSD4148

D109 MMSD4148

PC200A

SFH817A

2

1

C106 100 n

PC200B

SFH817A

4

3

D107

MMSD4148Q102

BC848ALT1

C10110p 1KV

STANDBY

VS-Stby

POWER_OK

RELAY1

VS-Stby

V1

RELAY2

VCC3VCC4

Standby_supply

STANDBY

VS1

Regulation

VS-Stby

VS2

ON-OFF Switch

"Optional"

POWER_OK

Standby power and signal

To Signal processing board

HV Barrier



46” Flat TV PSU - Backlight Interface

• Interconnection on Power to any Backlight

solutions

– 400 Vdc / 200 W

– PFC OK

– 5 V and 12 V

– Power Good

•Separated & Dedicated Backlight solutions

– High Voltage LIPS for CCFL / EEFL

– High DC Output Voltage HB LLC for LED Driver

– Classical 24 Vdc HB LLC

– PDP dedicated Power converter



46” LIPS Inverter

• Higher power LCD-TVs – With extension to 40/42” or 52” /55” for both CCFL or EEFL

– Follow on of 32” LIPS Reference Design

– Full Bridge fixed frequency ZVS with possible synchronization

– High efficiency, low EMI and sinusoidal lamp current

• Dedicated LIPS module – To be interconnected with 46” Power Ref Design Step 1 < 13 mm

– Microsemi Backlight control ler LX6503

• ON Semiconductor IC’s – 2 High Side Drivers NCP5111

– 1 single signal driver transformer

• Low profile design – < 13 mm on top of PCB



Power (PFC + Flyback + Standby SMPS)

LIPS - High Voltage Back-light Inverter

CrM Interleaved

PFC

NCP1631

400 VdcOFF in Stand-by

Full Bridge Inverter

2 x High Side Driver

NCP5111

OFF in Stand-by

QR FlybackSMPS

NCP1379

OFF in Stand-by

Mains Input

90-264 Vac

12 Vdc

5 Vdc

St-by / ONBias

LCD TV

Signal

processing

and

Audio

amplifiers

Back-light

Controller

LX6503

CCFL

Current

sensing

I Lamp regulation

OCP, OVP

PWM 2

PWM 1

13 Vdc Audio

Current

balancing

Board

Stand by SMPS

NCP1053A5 Vdc-

Stand-by

Open lamps

protection

Relay

Power Good

ON/OFF, Dimming,Synchro

ON/OFF

46” LIPS Inverter Block Diagram



46” LED Backlight Power

• Higher power LCD-TVs – With extension to 40/42” or 52” /55”

– HB LLC dedicated to Backlight power

– High DC output voltage to power directly LED drivers

• Separate / Dedicated LED Power module – To be connected with 46” Power Ref Design step 2 < 8 mm

• ON Semiconductor IC’s – New NCP1397

– New

– New LED driver controller CAT4206

• Low profile design – < 8 mm on top of PCB (< 12.5 mm total)



Multiple LED Linear Drivers with CAT4026

• Up to 6 channels with linear bipolar transistors Linear:• “ Vf monitoring and supply modulation & control”

Dedicated SMPS to support output voltage modulation



46” Linear Edge LED Driver TV Block Diagram

Dedicated

SMPS for

Backlight

with

Modulated

output vol tage



46” Linear LED Driver Backlight Solution

Ultra SLIM design < 8 mm / 12.5 mm total

• Special technologies

• PCB size: 250 mm x 165 mm



HB LLC for Ultra Slim SMPS

• Limited number of components

• Zero Voltage Switching (ZVS)

• Zero Current Switching (ZCS)

• Higher power density

High efficiency and EMI friendly for low profile SMPS



Resonant Inductance Location?

Benefits:

• flexibility

• EMI• use resonant coil for OCP

Drawbacks:

• cooling

• insulation

External resonant coil is better for ultra slim design

External inductance Internal leakage inductance

Benefits:

• insulation

• cooling

• One component

Drawbacks:

• flexibility

• EMI + stray flux• window utilization



Secondary Rectification

Benefits:

• voltage drop

• Single diodes

Drawbacks:

• secondary winding

• matching

• window utilization• Higher voltage rectifiers

Bridge rectifier is better for HV output applications

Push-pull configuration Bridge rectifier

Benefits:

• one winding

• Lower voltage diodes• Matching

Drawbacks:

• Higher losses



NCP1397 - LLC Stage Controller

NCP1397 is cost effective and highly safe solution

Features:

- operation from 50 kHz up to 500 kHz

- 600 V driver

- Startup sequence via an externally adjustable soft-

start

- Brown-out protection combined with latch input

- Disable input for ON/OFF control (skip mode)

Benefits for backlight application:

• No driver transformer

• Simple skip mode

• Simple OCP



New OCP Implementation

Res. Coil aux. winding provides accurate and fast OCP

• Adjustable delayed fault

• Short circuit protection with frequency shift

• New Double phase current information from auxiliarywinding of resonance coil



Output Voltage Modulation

CAT4026 sinks

current from FB

divider to increaseoutput voltage

• Linear LED Drivers impact – Dedicated SMPS to support output voltage

modulation

– Does not allow to get added auxiliary voltages for

Audio & Signal processing

Single Output Voltage modulated for Linear Driver



HB LLC Schematic for Linear LED Driver



• Strong load variation (0 to 100%)on HB LLC with 100 Hz dimming

• Traces:

– Top: Output current from 0 to 1 A (0.5 A/div)

– Middle: Primary current 2 A/div

– Bottom: Output voltage ripple2 V/div (120 Vdc)

• Top picture: 50% dimming

– HB LLC works in Burst

– Up to 3 Vpeak ripple on Vout

• Bottom picture: 5% dimming – HB LLC works in Burst

– < 0.5 Vpeak ripple on Vout

HB LLC Waveforms

Ed LIT LED B kli hti T d



Edge-LIT LED Backlighting Trends

• ‘LED Light bars’ vary in configuration

– Single LED Strings of High Power (~ 200 V+ , 100 mA+)

– Multiple LED Strings (up to 4) of Lower Power (~ 100 V+ ,

50 mA+)

LED Driver solutions must handle from 4 to 16 channels



E i i LED D i B kli h S l i



Existing LED Driver Backlight Solution

• Large-size panel power Module used for 6 Channel Edge-LIT LED TV

• Each channel has a Dedicated Driver IC + inductive DC/DC boost + switch

6 Ch = 6 x ( DC-DC Boost +

additional switch )

6 Ch = 6 x Driver IC

M lti h l “ Li ” Ed Lit S l ti



Multi-channel “ Linear” Edge-Lit Solution

• Cost effective solution to address a wide number of channels

• VF Monitoring to dynamically adjusts Anode voltage

• Efficiency target range >90%, 94% typ. (varies with LED

mismatch)

• Thermal dissipation addressed by external Power BJT’s

• Address various LED string faults

“ Linear LED Driver” : A cost effective solution for multiple channels

M lti h l “ Li ” Ed Lit S l ti



Multi-channel “ Linear” Edge-Lit Solution

• 6 channel configuration shown

Fault diagnosticsExternal powerdevices (low JA)

LED Cathode regulation ~3 VLED-Anode : dynamic adjustment

LED Cathode OVP

Multi channel “ Linear” Edge Driver Schematic



Multi-channel Linear Edge Driver Schematic

DPAK or TO220FP Power stage

Current sense

OVP UVP

Connection to the 6 Edge LED segments

Optimized Dynamic LED Anode Control



Optimized Dynamic LED-Anode Control

TYPICAL EFFICIENCY

80%

85%

90%

95%

100%

0% 5% 10% 15% 20%

LED STRING MISMATCH [Pk-Pk]

E F F I C I E N C Y

200V

100V

'LINEAR' POWER DISSIPATION

0

5

10

15

20

0% 5% 10% 15% 20%

LED STRING MISMATCH [Pk-Pk]

D I S S P A T I O

N [ W A T T S ]

6ch: 200V, 100mA (120W)12ch: 100V, 50mA (60W)

V modulation & control to limit overall Power dissipation

• Efficiency depends on LED string matching

• 200V LED strings (with 10% mismatch) delivers ~ 94% efficiency

• Thermal power dissipation levels : ~ 5 to 10 watt range

LED Channel Current Matching



LED Channel Current MatchingVARIATION vs BASE CURRENT

-0.6%

-0.4%

-0.2%

0.0%

0.2%

0.4%

0.6%

0 2 4 6

BJT BASE CURRENT [mA]

V A

R I A T I O N

VARIATION vs LED CATHODE

-0.6%

-0.4%

-0.2%

0.0%

0.2%

0.4%

0.6%

3 6 9 12 15 18 21 24 27 30

CATHODE VOLTAGE [V]

V A R I A T I O N %

.

CHANNEL MATCHING %

-1.0%

-0.5%

0.0%

0.5%

1.0%

Ch1 Ch2 Ch3 Ch4 Ch5 Ch5

CHANNEL

M A T C

H I N G %

• Init ial channel matching tolerance ~ ± 0.5%

• Variation with BJT Base current : < 0.25%

• Variation with Cathode to 30V : < 0.15%

• Overall Channel matching less than ± 2%

Very good current matching < +-2%



Edge LED Linear Backlighting Summary



Edge LED Linear Backlighting Summary

• Provides reduced total solution cost

• VF monitoring minimizes & optimizes power dissipation

• Minimizes EMI

• Offers competit ive Channel to Channel LED matching

• Offers competitive wide range PWM dimming with good linearity

• Supports Fault diagnostics against Open-LED and Short-LED

modes

The Linear is a easy to design and cost effective solution

Conclusion



Conclusion

• Complete roadmap of LCD TV solutions – 32” LIPS

• A cost optimized solution for CCFL from 26” up to 42”

– 46” Power

• Power for any type of Backlight from 40” up to 55” < 13 or 8

mm

– 46” LIPS

• < 13 mm with separate LIPS

– 46” Edge LED

• SLIM < 8 mm with separate LED Drivers with very efficient

Linear Edge LED driver solution

• Approach

– Synergy by re-use solutions, speeding up the design process



Documents

Howled Tvs Work