AC-DC LCD TV Poower Architecture and LED Backlight.pdf

7/26/2019 AC-DC LCD TV Poower Architecture and LED Backlight.pdf

1/53

AC-DC LCD TV Power Architecture

andLED Backlight


2/53

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


3/53

LCD-TV Shipments by Size

Source: Displaysearch 2Q 09


4/53

Power Reduction Trend Regulatory reduce power

consumption 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


5/53

Proposed ENERGY STAR rev4.0 Standards

Target Effective Date: May 2010

Very few LCD-TV passproposed new standard,

most are Samsung LED


6/53

LCD-TV LED Backlighting

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

Source: DisplaySearch July 2009


7/53

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-channellinear

High voltage Boost, buck, linear with Vfadjustment

LEDdriver

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% ?


8/53

Power Architectures Remain Varied

PFCCRM

Interleave FCCrMCCM

70 - 400+ W

Signal Power Flyback

Resonant HB30 80 W

Backlight Power Flyback / Resonant HB

24V / 150V+ for LEDHV-LIPS for CCFL / EEFL

50 300 W

Traditional 24 V Backlight and HV-LIPS approachThin TV design impacts solutions choices as well

ECO Standby< 5 W


9/53

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 P ower S upply

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


10/53

32 HV-LIPS LCD TV Block Diagram


11/53

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


12/53

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 profile design 1 st phase: < 13 mm 2nd phase: < 8 mm


13/53

46 LCD TV Power Block Diagram


14/53

46 LCD TV Power Solution Unit (PSU)

Low Profile design < 13 mm / 17.5 mm total


15/53

46 LCD TV PFC Solution

Up to 300 W Interleaved Frequency Clamp CrMPFC Better EMI and EMC Lower I rms 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


16/53

PFC Summary


17/53


18/53

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 internaltimer


19/53

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


20/53

46 LCD TV Flyback Schematic

2_5VREF

D207

MBRF20L80CTGto220

1 2

3

Flyback power toSignal processingand Audio board

R228 1K

Backlightcontrollersupply toBacklight

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

R21410k

R2051K

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

PC101ASFH817A

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


21/53

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


22/53

ECO Standby SMPS Solution (1)

Dedicated 5W ECO Power Standby SMPS

P in < 90 mW for P out = 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


23/53

ECO Standby SMPS Solution (2)

Standby relay Disconnect all parasitic standby load (~100-150

mW @ 230 Vac)

Directly controlled by TV P

Optional ECO ON / OFF switch Low cost 2A / 10V non-isolated switch

OFF mode: P in < 20 mW by no load @ 230 Vac

ECO switch provides ON/OFF without Mains switch


24/53

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: P in < 20 mW @ 230 Vac (15 @ 120 Vac)Standby / 40 mW Out: P in < 90 mW @ 230 Vac (86 @ 120 Vac)


25/53

ECO Standby SMPS Waveforms Drain Voltage and Current of

NCP1053A Switcher 200 V/div & 200 mA/div

For 5 V & 1 A = 5 W Output

Left: Hysteretic Burst mode (100 s/div)

Right: Detailed cycle

(4 s/div)

Top Trace: 90 Vac

Middle Trace: 230 Vac

Bottom Trace: 264 Vac


26/53

ECO Standby SMPS Schematic

VS-Stby

VCC2

VCC1

PC100A

C10710nF

SFH817A

2

1

R103 8.2K

R1101K

R1011K

Q103

BC848ALT1

CN1014324-05S

12345

Q100

BC858ALT1 3

1

2

R120 0

Q101 BC808-25LT13

1

2R10410K

+

C104

10u 25 V

R11922K

J100INSTALL

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

PC001BSFH817A

4

3

R100100K 1/4W

D102

BAV21

ZD101 MMSZ5V1T1

R11110K

D108 MMSD4148

CN1004324-02S

12

D105

MMSD4148

R10910K

C100220p 400V

L100

10uH1 2

R10230K

R1174.7K

R1074.7K

PC100B

SFH817A

4

3

D110 MMSD4148

ZD102 MMSZ15T1

D106MMSD4148

R10510K

T100750871014

7

83

14

5 6

9

R106470

+ C102

470 16V

P

N

R1121K

R1084.7K

+ C10347 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 signalTo Signal processing board

HV Barrier


27/53

46 Flat TV PSU - Backlight Interface

Interconnection on Power to any Backlightsolutions

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


28/53

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 ICs 2 High Side Drivers NCP5111 1 single signal driver transformer

Low profile design < 13 mm on top of PCB


29/53

Power (PFC + Flyback + Standby SMPS)

LIPS - High Voltage Back-light Inverter

CrM InterleavedPFC

NCP1631400 Vdc

OFF in Stand-by

Full Bridg e Inverter

2 x High Side DriverNCP5111

OFF in Stand-by

QR FlybackSMPSNCP1379

OFF in Stand-by

Mains Inpu t90-264 Vac

12 Vdc5 Vdc

St-by / ONBias

LCD TVSignal

processingand

Audio

amplifiers

Back-lightController

LX6503

CCFL

Currentsensing

I Lamp regulationOCP, OVP

PWM 2

PWM 1

13 Vdc Au dio

Currentbalancing

Board

Stand by SMPSNCP1053A

5 Vdc-Stand-by

Open lampsprotection

Relay

Power Good

ON/OFF, Dimming,Synch ro

ON/OFF

46 LIPS Inverter Block Diagram


30/53

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 ICs New NCP1397 New

New LED driver controller CAT4206

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


31/53

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


32/53

46 Linear Edge LED Driver TV Block Diagram

DedicatedSMPS for Backlight

withModulated

output vol tage


33/53

46 Linear LED Driver Backlight Solution

Ultra SLIM design < 8 mm / 12.5 mm total

Special technologies PCB size: 250 mm x 165 mm


34/53

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


35/53

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


36/53

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


37/53

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


38/53

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


39/53

Output Voltage Modulation

CAT4026 sinkscurrent 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


40/53

HB LLC Schematic for Linear LED Driver


41/53

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 ripple

2 V/div (120 Vdc)

Top picture: 50% dimming HB LLC works in Burst Up to 3 V peak ripple on V out

Bottom picture: 5% dimming HB LLC works in Burst < 0.5 V peak ripple on V out

HB LLC Waveforms


42/53

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


43/53

Existing Large Panel Backlight Solution

Advantage: Independent Channel

Efficiency and LED-Fault handlingLoosely regulated input supply

Drawback: Cost and Complexity

Loosely ~100V

For each LED channels!


44/53

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


45/53

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 LEDmismatch)

Thermal dissipation addressed by external Power BJTs

Address various LED string faults

Linear LED Driver : A cost effective solution for multiple channels

M l i h l Li Ed Li S l i


46/53

Multi-channel Linear Edge-Lit Solution 6 channel configuration shown

Fault diagnostics External powerdevices (low JA)

LED Cathode regulation ~3 VLED-Anode : dynamic adjustment

LED Cathode OVP

M lti h l Li Ed D i S h ti


47/53

Multi-channel Linear Edge Driver Schematic

DPAK or TO220FP Power stage

Current sense

OVP UVP

Connection to the 6 Edge LED segments

O ti i d D i LED A d C t l


48/53

Optimized Dynamic LED-Anode ControlTYPICAL 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

200V100V

'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


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LED Channel Current MatchingVARIATION vs BASE CURRENT

-0.6%

-0.4%

-0.2%

0.0%

0.2%

0.4%

0.6%

0 2 4 6BJT 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 30CATHODE 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%

Optimized Wide PWM Dimming Range


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Optimized Wide PWM Dimming Range

No concept limitationfor very short ONtime

CAT4026 LinearDriver is optimizedfor PWM dimming

Strong powervariation manageddirectly by SMPS

BRIGHTNESS vs PWM DUTY

0%

1%

10%

100%

0% 1% 10% 100%PWM DUTY CYCLE

C U R R E N T %

[ F S B ]

Down < 1% for 400Hz PWM dimming

Edg LED Li B klighti g S


51/53

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


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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 8mm

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

F M I f ti


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For More Information

View the extensive portfolio of power management products from ON

Semiconductor at www.onsemi.com

View reference designs, design notes, and other material supportingthe design of highly efficient power supplies at

www.onsemi.com/powersupplies

Documents

AC-DC LCD TV Poower Architecture and LED Backlight.pdf