TI high efficiency LLC resonant controller and synchronous ...cn.21ic.com/ebook_download/microsite/power/TI high... · Typical High Watt (>100W) LED Lighting Driver Topology 1. AC/DC

Texas Instruments System Power Solutions-High efficiency LLC resonant controller and

synchronous rectifier

Texas InstrumentsPower Management

AGENDA

1. UCC25710 Multi-strings LLC LED driver1. Features and Application2. Block Diagram3. Operating descriptions and evaluation results:

2. UCC25600 LLC controller1. LLC operating descriptions2. Block diagram and features:

3. UCC24610 Synchronous driver:1. Features and Application2. EVM and test results:

Typical High Watt (>100W) LED Lighting Driver Topology

1. AC/DC Power Stage 2. Constant Current Driver Stage

PFCAC

~54Vdc Bus

BUCK Control

BUCK Control

LLC Converter

+

UCC28061( Inter TM PFC)UCC28810/1(TM PFC)

TPS40211

TPS40200

TPS54160

TPS40211

TPS40200

TPS54160

UCC25600 (LLC)

~15pcs

LEDsin Series

Buck Control

PFC ControlEMI

Outdoor and Industrial >100W

Q1

Q2

Lr

Lm

Cr

LLC Control

Buck Control

400V

High Watt (>100W) LED Lighting Efficiency Budget

Conventional Topology Issues: High cost: PFC+LLC+CC BUCK (multi-chips!!) Low efficiency (<~88%) Low reliability (many components’ counts) EMI issues

97% 96%

95%

<88% (Traditional solution)

Series Input, Multiple Parallel Equivalent LED Drive (SIMPLEDrive )

TI UCC28810EVM-003 - SIMPLEDrive™1st stage:

TM Boost for PFC2nd stage:

TM Buck for LED current3rd stage:

Resonant Current Half Bridge

97% 98% 98%

>93% (Three stages multi-string transformer solution)

Innovative two stages multi-string LLC topologyfor LED lighting

PFC Control

PWM Control HV

Gat

e D

river

EMIInput Bridge

Outdoor and Infrastructure >100W

BUCK

PFC Control

PWM Control

Gate

Drive

r

EMIInput Bridge

Outdoor and Infrastructure >100W 400Vdc

Ga Gb

CSUVOV

UCC25710

Benefits for the proposed topology:☺ High efficiency ~92% ☺ Low cost (no need CC DC/DC driver)☺ High reliability☺ Easy EMI☺ PWM or analog dimming compatible

new

UCC28810

UCC28811

UCC25600

UCC28810

Why Transformer Can Balance Current

• Transformer current is in reverse proportion to turn ratio

• Ip/Np = Is/Ns; Is=Ns*Ip/Np• When transformer primary is

connected together, their primary current must be the same

• When T1 is the same as T2 because of transformer operation principle their secondary current is the same

• Is1=Ns*Ip/Np=Is2

2

41

3

2

41

3

Np

Np

Ns

Ns

Ip

T1

T2Ip

Is1

Is2

Multi-Transformer Architecture(TI Patented)

One transformer control two LED strings!

PWNdimming

AC input

General LED Lighting

LED TV Backlighting Industry first single chip LLC controller for driving multiple LED strings directly from PFC outputAdjustable Fmin (3% accuracy), and Fmax 6% (accuracy)Closed Loop LED String Current ControlPWM Dimming InputLLC and Series LED Switch Control for DimmingProgrammable Dimming LLC ON/OFF Ramp for Elimination of Audible NoiseClosed Loop Current Control at Low Dimming Duty-CyclesProgrammable Soft StartAccurate VREF for Tight Output Regulation Over-voltage and Under-voltage and Input Over-current Protection with Auto-restart ResponseSecond Over-current threshold with Latch-off Response+400-mA/-800mA Gate Drive Current Low Start-Up and Operating Currents 20 pin SO Lead (Pb)-Free Package

UCC25710: LED driver Controller IC

20V-9.5V

DIM PWM Input

+–

+–

+–

VIN

LED String 1

LED String 2

LED String N

T1

T2

TN

ON / OFF

DSR

DIM

ICOMP

UV

FMAX

FMIN GD1

OV

CS

GD2

SS

VCC

VREF

GND

CL

LEDSW

UC

C25

710

BLON

CREF

DADJ

DTY

Current Regulation and VCO Slew Control

UCC25710Block Diagram

Supply Control

LLC Control

LED Switch and Dimming Control

Fault Control

1 +VVCCON/VCCOFF

9.3V/8.9V

5VRef

VVREF

Dea

d Ti

me

2

3

4

D Q

QCLR

RESET

20

19

GMICOMP510uS

18

UVLO

ISS2.5uA

16CS

SS

FMAX

FMIN

GD1

GD2

VCC

VSSTH4.2V

6 LEDSW

VVCO

D Q

QCLR

13 CL+

VCLTH1V/0.5V

GND

FAULT

GD Toggle

Edge Sync

GD Enable

VCLLTH1.9VSQ

Q R UVLO

Latch-Off

+

+ 12 OVVOVTH

2.6V/2.4V

11 UV

VUVTH

2.4V/2.6VSS-END

SS-END

5VREF

2*F

VVREF

FMIN

FSW

Zero Frequency Command

80K

80K

2.5uA

7

8

9

200KDIM

DADJ

DTY

VVREF

LH

Dimming PWM

OFF

ON

200K10BLON

15CREF

VVREF

~4V

H

LLC-OFF

LED-ON

LED-ON

SS-END

17

H

ICOMP

Soft Start

S Q

QR*

+

+

LLC-OFF

H

L

IDSRCH44uA

IDSRDC44uA

VVREF

14DSR

VVREF

SS Clamp

ControlClamp

1V 4V

VVCO

FMAX

VCOFSW

0.9V

Dimming Slew Control

GND

ICOMP

RST Gen

S* Q

QRdelay

UCC25710

+

RESET

RESET

TSD

ENBL

Disable

LATCH-OFFLow ICC

FAULTENBL

+++

VCLREFCLO, 0.5VVCLREFCHI, 2.8V

TRSTDLY10ms

IDADJCH20uA

4K

Current Amplifier

delay2.4us

UCC25710: DIMMING – LLC ON/OFF TRANSITION & CURRENT CONTROL

• The DIM input controls the ILED-ON an ILED-ON` signals.

• DSR capacitor C2 and internal 44uA currents control the slew rate of VVCOduring dimming off and on transitions.

– Turn-off: DSR is discharged to GND by 44uA

– Turn-on: DSR is charged to ICOMP by 44uA. Charge level is clamped to 1Vbe above ICOMP

• Control Clamp output, VVCO, tracks the lower of ICOMP and DSR

• ICOMP is only driven by GM amp during LED-ON times.

• During LED-OFF times the ICOMP voltage is held by C1

GMICOMP510uS

16CS

VVCO

VVREF

15CREF

17

H

ICOMP

+

ILED-ON�

L

H

IDSRCH44uA

IDSRDC44uA

VVREF

14

DSR

VVREF

ControlClamp

Dimming Slew Control

GND

ICOMP

+++

VCLREFCLO, 0.5VVCLREFCHI, 2.8V

4K

Current Amplifier

delay2.4us

VVCO

ILED-ON6

VCC

R3

R2

R1

5

VREF

C2

C1

LEDRETURN

LEDSW

UCC25710: START-UP & DIM WAVEFORMS

• 10ms RESET initiates Soft-Start (SS)

• LLC Soft-Start, VCO control is clamped to SS until SS > ICOMP

• Dimming is disabled during SS

• DSR cap is used to limit LLC control slew rate during dimming

• ICOMP voltage is maintained during dimming

VCC

DIM

SS

DSR

GD1,2

UVLO

RESET

LEDSW

9.3V

VREF

10ms

ICOMP

9.0V

Dimming Enabled

Soft-Start

OperationDisabled

Controller Enabled

Soft-Start Over

UCC25710: DIMMING – WAVEFORMS

• DIM input controls LEDSW

• DIM input triggers soft turn-on and turn-off of LLC converter

• LLC on-time is extended

• On-time extension is proportional to 1-D, D is dimming duty-cycle

• Extended on-time allows ICOMP to maintain current regulation at low D

Dimming

SS (VVCO)

LEDSW

ICOMP

DADJDTY

DIM

DTY = 0.1V + 2.5V*(1-D)

Added LLC On-Time

LLC On/OffSlew Rate

50% Dimming 10% Dimming

UCC25710: LOW DUTY-CYLE ILLUSTRATION1. LLC reaches power level equal to

pedestal LED current in region B. Power is under delivered in region A, but is compensated for in region C

2. Region B is zero, but sum of A+C still deliveries correct energy.

3. Energy delivered in region A + C is too low, loop is open and realized peak LED current will drop

4. On-time is extended. A + C energy/pulse is correct to maintain same peak LED current

LLC POWER RAMP

DIMMING PWM SIGNAL

A B CD D

LLC POWER RAMP

DIMMING PWM SIGNAL

A

B=0

CD D

LLC POWER RAMP

DIMMING PWM SIGNAL

A C

D D

LLC POWER RAMP

DIMMING PWM SIGNAL

A CD D

(1)

(2)

(3)

(4)

UCC25710: FAULT MANAGEMENT

• Faults– OV – highest LED string voltage– UV – lowest LED string voltage– CL(1V) – input current signal over-current– CL(2V) – input current signal latch-off– TSD – Chip thermal shutdown

• Response– OV, CL(1V) & TSD: The LLC converter and LEDSW are turned off. When

the fault clears a RESET and SS are initiated.– UV: The LLC converter and LEDSW are turned off. A RESET and SS are

immediately initiated, repeatedly, until fault clears.– CL(2V): The LLC and LEDSW are latched off until UVLO recycles.– During RESET the LLC converter and LEDSW are OFF– During SS the LLC converter and LEDSW are ON, i.e. no DIMMING

PMP4302: Multi-string LLC AC/DC Driver for general LED lighting

92%

Eff.

PWM dimming

Dimming

TM PFC+Multi-string LLC converter

Topology

54V@500mA with 4 string

90V~264V

UCC28810(TM PFC)UCC25710(Multi-string LLC)UCC28610(Aux Flyback)

PMP4302:AC input Multi-string LLC converter for general LED lighting

TI Parts OutputVinReference Design

Features• Lowest cost than AC/DC + DC/DC• Highest efficiency to 92%• PWM dimming compatible• Integrate LED open/short protection and over current

protection

Applications• General LED lighting and LED backlight TV

PFC Control

PWM Control

Gat

e D

river

EMIInput Bridge

Outdoor and Infrastructure >100W 400Vdc

Ga Gb

CSUVOV

UCC28810

UCC25710

PMP4302 demo board

Input EMIPFC

Stage Multi-string LLC Stage

Aux Power

LED light bar4x15LEDs

PMP4302: Schematics for UCC25710 after PFC stage

PWM dimming &

Total current sensing

feedback

Multi-string transformer LLC topology

PMP4302: LED current output tolerance

1.084511.7512.4501.4503.9100%

1.045506.2507.2496.7499.399%

0.973460.1461.1452.2454.390%

0.923408.8409.7402.2403.980%

0.956357.8358.6351.8353.570%

1.033307307.7301.4302.960%

1.043255.8256.4251.1252.450%

1.033204.9205.1200.9201.940%

1.214153.6154.1150.4151.430%

1.280102.5102.7100.1100.920%

1.77451.351.549.750.410%

2.20825.125.224.125.25%

2.96210.310.49.8102%

3.0305.154.84.91%

%Io4Io3Io2Io1PWM

Dimming

0.505

0.507

0.509

0.511

0.513

0.515

90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260

Input Voltage(V)

Out

put C

urre

nt (A

)

Current tolerance can achieve <+-3% with dimming range from 1% to 100%

230V ac input LED output current Vs Input voltage

w/ 100% dimming

PMP4302: Efficiency (TM PFC + Multi-string LLC + Aux power)

0.85

0.86

0.87

0.88

0.89

0.9

90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260

Input Voltage(V)

Effi

cien

cy

0.87

0.88

0.89

0.9

0.91

0.92

90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260

Input Voltage(V)

Effi

cien

cyDimming version Non-Dimming version

PMP4302: waveforms

1% dimming 5% dimming

50% dimming 90% dimming

CH1: LEDSW MOSFET Vgs5V/DivCH2: LED Output Current 1A/DivCH3: DSR 2V/DivCH4: Primary Current 1A/Div

PMP4302: waveforms

90Vac input

230Vac inputCH1: Primary MOSFET Vds 100V/DivCH2: LED Output Current 200mA/DivCH4: Primary Current 1A/Div

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.5 1 1.5 2

Wn

M

Full Load

Half Load

20% Load

Lm/Lk=6Fs=100KHzQ=0.7

Lm1+Lm2=640uHLr=100uHCr=30nF

CCM to get better current tolerance

PMP4302: Thermal and Bode Plot

PMP6251: LED Backlighting for Edge-Lite/ Group Dimming Digital TV Application

Reference design Features Support to universal 90~264Vac range

LED 4 outputs @120mA, 63V, 5Vsb@1A, 5V@3A, 13V@3A

Eff 83.7%@110Vac, 85.2%@240Vac

Secondary side 120Hz blanking control for dimming

8mm height and 6mmheight for LED magnetic component

Board dimension 300mm(L) * 200mm(W) * 8mm(H)

LED output common + and LED OVP and UVP

Integrated the protection ckt to reduce the solution part count.

Dedicated controller for edge-lit/ group dimming base on the LLC topology – UCC25710

Providing design package – Schematic, Gerbo file, PCB file, Magnetic components…

TM PFCUCC28051

GM PWMUCC28610

UtilityUtility(90~265VAC)

Multi-TransformerUCC25710

Audio 12.7V/3A

System- MCU (+5VSB/2A)

LLC PWM UCC25600

4 Channels/ 63V/120mA

AD Board 5V/3A

PMP6251: PFC+ Multi-string LLC Efficiency

Efficiency exclude standby Power Converter at full load condition ~ 90%

Efficiency Data of PFC+LLC Power Stage from 1% - 100% Dimming

80.00%

82.00%

84.00%

86.00%

88.00%

90.00%

92.00%

0% 20% 40% 60% 80% 100%

Eff% of (PFC+LLC)

Rat

e of

Dim

min

g

Eff%(PFC+LLC)

Summary• UCC25710 with multi-transformer LLC topology can achieve:

☺High efficiency☺Low total BOM cost with high reliability☺PWM or analog dimming compatible☺Output LED strings open/short protection☺Input over current protection☺Support 1%~100% dimming range☺Easy EMI

Summary

• LED backlight becomes a trend for flat screen TVs• TI proposed multi-transformer backlight solution

– Simple current matching method– Single stage power processing– Fault tolerant capability

• UCC25710 provides the IC solution for multi-transformer architecture

• Multi-Transformer LLC + LED switch control• Precision LED current control• Soft ramping of LLC for audible noise reduction• Extended PWM dimming dynamic range• Complete protection features

TI UCC25600 8 Pin Resonant Half Bridge Controller

1

2

3

4 5

6

7

8 GATE1

VCC

GND

GATE2

Td

RT

OC

SS

Features Adjustable Soft start (1ms to 500ms) Adjustable dead time Adjustable Fswmax & Fswmin (3% accuracy)

Io = +1A /-1.5A Enable (ON/OFF control)

Protection functions Two levels over current protection auto recovery latch

Bias voltage UV and OV protection Over temperature protection Soft start after all fault conditions

SOT 8 pin package= Easy design and layout

Ready to Order

Application Circuit360~400V

DC_OUT

Vcc

11

11

11

11

Td

RT

OC

SS

Gate1

Gate2

Vcc

GND

Programmable dead timeFrequency control with minimum/maximum frequency limitingProgrammable soft start with on/off controlTwo level over current protection, auto-recovery and latch upMatching output with 50ns tolerance

LLC Resonant Converter with Wide Operation Range

At 400V input, switching frequency is resonant frequency

During holdup time, switching frequency is reduced

o

in

VVn 2/

=Transformer turns-ratio

o

in

VVn 2/

=Transformer turns-ratio

Cr Lr

Lm

n:1:1

VinVo

RL

rrCLf

π21

0 =Resonant frequency rrCL

fπ2

10 =Resonant

frequency

0

0.5

1

1.5

2

2.5

3

3.5

4

0.4 0.6 0.8 1 1.2

Q=0.1Q=0.2Q=0.5Q=0.8Q=1Q=2Q=5Q=8Q=10

fn

M=V

o/Vin

ZCS Region

ZVS Region

Operation PrinciplesAt Resonant Frequency

Vg_Q1

Vg_Q2

Vp

ir

im

is

t

t

t

t

t

t0 t1 t2 t3 t4

Cr Lr

Lm

n:1:1

VinVo

RL

Q1

Q2

D1

D2

**

*

At resonant frequency, maximum efficiency is expected

Operation PrincipleBelow Resonant Frequency

Cr Lr

Lm

n:1:1

VinVo

RL

Q1

Q2

D1

D2

**

*

t0 t1 t2 t3

Vg_Q1Vg_Q2

Vp

ir

im

is

t0 t1 t2 t3

Vg_Q1Vg_Q2

Vp

ir

im

is

When switching frequency is below resonant frequency, magnetizing inductor begins to participate in resonant and increase voltage gainSecondary diode becomes discontinuous

Operation PrincipleAbove Resonant Frequency

t0 t1 t2 t3

Vg_Q1Vg_Q2

Vp

ir

im

is

Cr Lr

Lm

n:1:1

VinVo

RL

Q1

Q2

D1

D2

**

*

When switching frequency is above resonant frequency, circuit behaves as SRCSecondary current becomes CCM, reverse recovery loss increases

Benefits of LLC Resonant Converter

Cr Lr

Lm

1:n:n

ZVS can be achieved by utilizing transformer magnetizing inductor Capacitor filter, less voltage stress on rectifiers Smaller switching loss due to small turn off current Variable switching frequency control, not sensitive to load change Wide operation range without reducing normal operation efficiency

UCC24610Green Rectifier Controller

• AC/DC Adaptors• Mobile Chargers – Cell Phone, IPod• Set Top Box• Appliance Power Supplies• Bias Supplies

• Highly Integrated Control

• Automatic Light Load Management

• Micro Power Sleep Current at light/No load

• Secondary Side Synchronous Rectifier Controller for Flyback and LLC Converters

• Enables 90%+ efficiency at full load and Optimized Efficiency Over Entire Load Range

• Turns MOSFETS Off to Maximize Light Load Efficiency

• Reduces External Components with up to 5% Reduction in Power Supply Costs

• Zero Glitch Transition between CCM and DCM Operation for varying Line or Load Changes

• Operates in Continuous and DiscontinuousMode Flybacks and LLC Resonant

• Dissipates less than 1mW in Sleep Mode Making Energy Star Goals easily Achievable

EVMAvailable

GATEVD VS TON GNDEN/TOFF

SYNC

VCCCSYNC RSYNC

CCM

VCC

UCC24610

+5V OUT

To Control Logic

iSYNC

iSYNC_RESET

+

CPIN

+

rSYNC

Adding Green Solutions to the Portfolio

IsolatedFeedback

LLC Or

Flyback

MOSFET Drivers

UCC24610Sync Rectifier

Driver

Green Rectifier

Green PWM ControllersUCC28610 Green Mode PWMUCC28600 Green Mode QR PWMUCC25600 Green Mode Resonant LLC

Expand the Operation Range of UCC24610

• With 50V maximum rating, UCC24610 has trouble to use in 19V output LLC• LLC converter with voltage doubler can be used to extend the operation range of

UCC24610• No center tap, simpler transformer structure

• Less voltage drop on the SR, better devices can be used• UCC24610 can be powered up using on aux power source with boots trap diode

UCC24610 Competitive Analysis

Key Differentiators• High Gate Drive current• Auto Light Load Mode• Open/Short Protection

TI IR NXP NXP ST ON ON Gren Zerex

Parameter/Device: UCC24610 IR1166S(8) TEA1761T TEA1791T STSR30 NCP4302 NCP4303B(9) GR8387 ZXGD3101T8Vdrain (V) 50 200 120 120 (ext. clamp) 95 200 200 180

Conduction Modes DCM, QR, CCM DCM, QR, CCM DCM, QR DCM, QR DCM, QR, CCM DCM, QR, CCM DCM, QR, CCM DCM, QR, CCM DCM, QR, CCMGATE Ion (Apk) -3 -1 -0.25 -0.25 -1.5 2.5 2.5 1 2.5GATE Ioff (Apk) 3 4 2.7 2.7 1.5 -2.5 -5 -4 -2.5Max Freq (kHz) 600 500 ? ? 500 250 500 500 n/a

Packages PwrQFN-8, SO-8 SO-8 SO-8 SO-8 SO-8 SO-8 SO-8 SO-8 SO-8Rthja (C/W) 67, 147 128 150 150 160 178 180 128 250

Tj Range (C) -40 to +125 -25 to +125 -20 to +128 -20 to +128 -40 to +125 -40 to +125 -40 to +125 Unknown (5) Unknown (5)

Special Features:Enable function Yes Yes No No Yes No Yes Yes No

Auto Light-Load Mode Yes No Yes Yes No No No No NoInductance Compensation No No No No No No Yes No No

Open/Short Protections Yes None Indicated None Indicated None Indicated None Indicated None Indicated None Indicated None Indicated None IndicatedRegulated Opto-drive No No Yes No No Yes No No No

Gate Voltage Reduction No No Yes Yes No No Yes No YesOver-temp Protection No No Yes No No No No No No

5.6V/3A AC Adapter:

12V/40A Server Application:

85%

86%

87%

88%

89%

90%

91%

92%

93%

94%

95%

0 4 8 12 16 20 24 28 32 36 40

Effic

ienc

y

Load Current (Amps)

UCC24610 in 19.5V LLC AC Adapter Application

Synchronous rectifier in LLC converter

System implementation

• Waveforms– YEL (Primary current) 1

A/Div– BLU (Lower SR VDS) 10

V/Div– GRN (Upper SR VGS) 10

V/Div– RED (Lower SR VGS) 10

V/Div• Horizontal scale

– 2 µs/Div• Operating conditions

– VI =320 V– IO =1.0 Adc (20 W)– fSW below resonance

Test Results







– VI =390 V– IO =1.0 Adc (20 W)– fSW close to resonance

Test Results







– VI =420 V– IO =1.0 Adc (20 W)– fSW above resonance

Test Results








Test Results








Test Results








Test Results








Test Results








Test Results

• Waveforms– YEL (Primary current)1 A/Div– BLU (Lower SR VDS)10 V/Div– GRN (Upper SR VGS) 10V/Div– RED (Lower SR VGS) 10V/Div

• Horizontal scale: 2 µs/Div• Operating conditions


Test Results

Operating Efficiency with UCC2461090-W LLC Laptop Adapter (UCC24610) - Efficiency

70

75

80

85

90

95

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

IO (A)

Effic

ienc

y (%

)

SRDiode

VI (V)

More than 6% efficiency improvement is achieved by using UCC24610 with Synchronous rectifier

Thank You!

Documents

TI high efficiency LLC resonant controller and synchronous ...cn.21ic.com/ebook_download/microsite/power/TI high... · Typical High Watt (>100W) LED Lighting Driver Topology 1. AC/DC