LIPS Solution for LED TV Backlighting. Aug. 23 th, 2010 Anderson Hsiao



Similar documents
Multi-Transformer LED TV Power User Guide. Anderson Hsiao

Texas Instruments. FB PS LLC Test Report HVPS SYSTEM AND APPLICATION TEAM REVA

Wireless Subwoofer TI Design Tests

LM5030 LM5030 Application: DC - DC Converter Utilizing the Push-Pull Topology

AMC1100: Replacement of Input Main Sensing Transformer in Inverters with Isolated Amplifier

TI Designs Precision: Verified Design Comparator with Hysteresis Reference Design

Chapter 4. LLC Resonant Converter

Design Considerations for an LLC Resonant Converter

AC/DC Power Supply Reference Design. Advanced SMPS Applications using the dspic DSC SMPS Family

AND8147/D. An Innovative Approach to Achieving Single Stage PFC and Step-Down Conversion for Distributive Systems APPLICATION NOTE

AP KHz, 2A PWM BUCK DC/DC CONVERTER. Description. Pin Assignments V IN. Applications. Features. (Top View) GND GND. Output AP1509 GND GND

7-41 POWER FACTOR CORRECTION

August 2001 PMP Low Power SLVU051

National Semiconductor Power Products - Seminar 3 (LED Lighting)

LED Drivers For Lighting

IR1168S DUAL SMART RECTIFIER DRIVER IC

V OUT. I o+ & I o- (typical) 2.3A & 3.3A. Package Type

DN05034/D. Enhanced PWM LED Dimming DESIGN NOTE

LM134-LM234-LM334. Three terminal adjustable current sources. Features. Description

AC/DC Power Management Devices Product Guide. AC/DC Control ICs with integrated MOSFETs in LLC, QR & PWM Topologies

Together, we work as a team.

LDS WLED Matrix Driver with Boost Converter FEATURES APPLICATION DESCRIPTION TYPICAL APPLICATION CIRCUIT

AND8480/D. CrM Buck LED Driver Evaluation Board APPLICATION NOTE

HEF4021B. 1. General description. 2. Features and benefits. 3. Ordering information. 8-bit static shift register

TSL250, TSL251, TLS252 LIGHT-TO-VOLTAGE OPTICAL SENSORS

Simple PWM Boost Converter with I/O Disconnect Solves Malfunctions Caused when V OUT <V IN

LM556 LM556 Dual Timer

Theory of Operation. Figure 1 illustrates a fan motor circuit used in an automobile application. The TPIC kω AREF.

Quad 2-input NAND Schmitt trigger

Power supplies. EE328 Power Electronics Assoc. Prof. Dr. Mutlu BOZTEPE Ege University, Dept. of E&E

Noise Free 90+ for LCD TV AC Adapter Desk Top. 96% x 96% = 92.16% Champion Microelectronic. 96+ Interleaved CRM PFC CM6565 PFC & PFC PWM PWM

HEF4011B. 1. General description. 2. Features and benefits. 3. Ordering information. 4. Functional diagram. Quad 2-input NAND gate

AP KHz, 3A PWM BUCK DC/DC CONVERTER. Pin Assignments. Description. Features. Applications. ( Top View ) 5 SD 4 FB 3 Gnd 2 Output 1 V IN

UNISONIC TECHNOLOGIES CO., LTD

AUIPS71411G CURRENT SENSE HIGH SIDE SWITCH

The 74LVC1G11 provides a single 3-input AND gate.

Understanding the Terms and Definitions of LDO Voltage Regulators

CS4525 Power Calculator

How To Make A Power Supply For A Flyback Power Supply

Analysis of Power Supply Topologies for IGBT Gate Drivers in Industrial

OLF500: High CMR, High-Speed Logic Gate Hermetic Surface Mount Optocoupler

Introduction to Power Supplies

FPAB20BH60B PFC SPM 3 Series for Single-Phase Boost PFC

1-of-4 decoder/demultiplexer

Application Report. 1 Description of the Problem. Jeff Falin... PMP Portable Power Applications ABSTRACT

Agenda. Introduction: NCP1631: a novel controller for interleaved PFC. Experimental results and performance. Conclusion

TOSHIBA Bipolar Linear Integrated Circuit Silicon Monolithic TAR5SB15~TAR5SB50

Preliminary Datasheet

SDLS068A DECEMBER 1972 REVISED OCTOBER Copyright 2001, Texas Instruments Incorporated

Switching Regulators. STR-A6169 Universal-Input/5 W Flyback Switching Regulator FUNCTIONAL BLOCK DIAGRAM

8-channel analog multiplexer/demultiplexer

All in One PC Power Supply Reference Design

HEF4013B. 1. General description. 2. Features and benefits. 3. Applications. 4. Ordering information. Dual D-type flip-flop

Providing Continuous Gate Drive Using a Charge Pump

Single-Stage High Power Factor Flyback for LED Lighting

Series AMLDL-Z Up to 1000mA LED Driver

SN54HC191, SN74HC191 4-BIT SYNCHRONOUS UP/DOWN BINARY COUNTERS

TN0023 Technical note

DISCRETE SEMICONDUCTORS DATA SHEET. BT151 series C Thyristors

SN54HC157, SN74HC157 QUADRUPLE 2-LINE TO 1-LINE DATA SELECTORS/MULTIPLEXERS

CAT V High Current Boost White LED Driver

IrDA Transceiver with Encoder/Decoder

SSM3K335R SSM3K335R. 1. Applications. 2. Features. 3. Packaging and Pin Configuration Rev.3.0. Silicon N-Channel MOS (U-MOS -H)

Tamura Closed Loop Hall Effect Current Sensors

EVL185W-LEDTV. 185 W power supply with PFC and standby supply for LED TV based on the L6564, L6599A and Viper27L. Features.

400KHz 60V 4A Switching Current Boost / Buck-Boost / Inverting DC/DC Converter

How to design SMPS to Pass Common Mode Lightning Surge Test

TOPOLOGIES FOR SWITCHED MODE POWER SUPPLIES

Triple single-pole double-throw analog switch

Custom Products. Magnetic Components. Vishay Dale.

Push-Pull FET Driver with Integrated Oscillator and Clock Output

CS V/250 ma, 5.0 V/100 ma Micropower Low Dropout Regulator with ENABLE

High Frequency True PWM Dimming White LED Driver MP3304 and MP3305

AAV003-10E Current Sensor

Output Filter Design for EMI Rejection of the AAT5101 Class D Audio Amplifier

LM709 LM709 Operational Amplifier

AP1510. General Description. Features. Applications. Typical Application Circuit PWM CONTROL 3A STEP-DOWN CONVERTER AP1510. x (1+R A = V FB /R B

Low-power configurable multiple function gate

LM2704 Micropower Step-up DC/DC Converter with 550mA Peak Current Limit

AND8433/D. Using ON Semiconductor Constant Current Regulator (CCR) Devices in AC Applications APPLICATION NOTE

CAT4109, CAV Channel Constant-Current RGB LED Driver with Individual PWM Dimming

1ED Compact A new high performance, cost efficient, high voltage gate driver IC family

Fairchild Reference Design RD-442

ULRASONIC GENERATOR POWER CIRCUITRY. Will it fit on PC board

NCP1612. Enhanced, High-Efficiency Power Factor Controller

Audio Tone Control Using The TLC074 Operational Amplifier

Application Note AN-1073

Datasheet. 2A 380KHZ 20V PWM Buck DC/DC Converter. Features

LM337. Three-terminal adjustable negative voltage regulators. Features. Description

SiGe:C Low Noise High Linearity Amplifier

Application Note, Rev.1.0, September 2008 TLE8366. Application Information. Automotive Power

High Performance Current Mode PWM Controller Cycle Turning + POWER FROM LIEMIC. For, 2008 LIEMIC Semiconductor Co.,Ltd. LN3C63AD REV: 1.0.

AND8451/D. Power Stage Design Guidelines for the NCL30000 Single Stage CrM Flyback LED Driver APPLICATION NOTE

INTEGRATED CIRCUITS. NE558 Quad timer. Product data Supersedes data of 2001 Aug Feb 14

SG6520 FEATURES DESCRIPTION TYPICAL APPLICATION. Product Specification. PC Power Supply Supervisors

Application Note AN-1070

AN-1733 Load Transient Testing Simplified

HV start-up DCM/QR flyback controller with integrated DCM/QR PFC controller

PAM2804. Pin Assignments. Description. Applications. Features. Typical Applications Circuit 1A STEP-DOWN CONSTANT CURRENT, HIGH EFFICIENCY LED DRIVER

SEMICONDUCTOR TECHNICAL DATA

Transcription:

LIPS Solution for LED TV Backlighting Aug. 23 th, 2010 Anderson Hsiao

Outline DTV Market Trend Multi-Transformer Current Balancing Advantage Compare to Traditional Driver Transformer Design & Component Selection Feedback, Dimming and Protection Test Result Conclusion Device Introduction ti

DTV Market Trend Worldwide DTV Market Forecast Worldwide Forecast for LCD TV Units with LED Backlight 240000 200000 160000 LCD TV PDP TV 100,000 80,000 u) Units (K 120000 80000 Units (Ku u) 60,000000 40,000 40000 20,000000 0 2007 2008 2009 2010 2011 2012 2013 0 2008 2009 2010 2011 2012 2013 Source: isuppli Worldwide TV Market Tracker Q3 2009 DTV market forecasted to grow at 15% CAGR with LCD-TV expected to account for 90% of total TV market by 2013 LED backlighting application is hot; 5 year CAGR of 141% Edge lit LED TV dominates (90%) market simpler, enable slim designs & cost effective CIP team strategy to support WLED TV backlighting applications; RGB will be supported by C2000 & DCP groups

Multi-Transformer Current Balancing Theory on Current Balancing using Transformer Multi-Transformer Architecture Explanation on why Output Current is not seriously impacted by Transformer Inductance.

Theory on Current Balancing using Transformer Ip Ip 1 T1 4 Transformer current is in Np Ns 2 3 1 T2 4 Is1 Transformer current is in reverse proportion to turns ratio Ip/Np = Is/Ns; Is=Ns*Ip/Np When the 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 Np Ns Is2 Is1 Ns Ip/Np Is2 2 3

Multi-Transformer Architecture (TI Patented) D1 VO1 1 T1 4 D2 VO2 2 3 C1 Isolation/balance D3 C3 C4 D4 D5 VO3 1 T2 4 D6 VO4 2 3 C2 Isolation/balance D7 C5 C6 D8

Output Current is not seriously impacted by Transformer Inductance Zone2 Current of bigger inductance Current of smaller inductance Transformer Primary Current Zone1 Because Zone1 is almost the same as Zone2, the transformer inductance do not seriously impact the output current

Multi-Transformer Solution Advantages compare to Traditional Driver (LLC + Boost + Current Balancing) Introduction to LED Backlight Driver solutions Comparison of the different LED Backlight solutions.

Solutions for Backlight Driver Power Supply Unit/ LIPS Architecture for LCD-TV Power Supply Architecture for LED Backlighting TV Today +24V for CCFL-BL Inverter DC-AC Inverter Cb1 Cb2 Cbn AC Input AC-DC PFC Main PWM 24V DC-DC Boost AC Input AC-DC PFC ST-BY PWM Main PWM +5VSB for MCU +12V for Audio-AMP L1 L2 Ln STBY PWM +5Vsb for MCU +12V Audio Controller IC LED Current Regulator AC Input AC-DC PFC +400V for CCFL BL-Inverter DC-AC Inverter Cb1 Cb2 Cbn AC Input AC-DC PFC Main PWM 24V DC-DC Boost ST-BY PWM +3.3VSB for MCU L1 L2 Ln +12-15V for Audio-AMP STBY PWM +5Vsb for MCU +12V Audio DC-DC Boost Controller

Comparison of Different LED Backlight Solutions Power Supply Architecture for LED Backlighting TV Today 1* DC Boost + 8-16 LED Current Regulators VIN= 24V Cin DC-DC Boost (Efficiency: 90%) VOUT=100V Co 30 LEDs Typ:100V 94% 96% 92% < 85% (Traditional Solution) HVM Driver Vd Vfet: Typ: 5V Power Supply Architecture for LED Backlighting TV in the Future UCC28051 UCC25600 Multi-transformer outputs designed on AC/DC LIPS power module (higher efficiency & low cost) inside DTV. 94% 96% Today- UCC25600 > 90% (Multi-Transformer Solution)

Multi-Transformer Design and Component Selection Transformer Design Key Component selection Feedback and Dimming Protection

Transformer Design For LLC transformer design, firstly we should transfer all parameter into the same unit. In this case we transfer all parameter into primary resistance. Considering 88V, 120mA load and two outputs for each transformer means each transformer output power is Pout 2 * Vout * I out 22. 2316W Because there are four transformers in series and half-bridge topology, we got following equation. 2 R P V ) V in 400V / 4( inseries) / 2( halfbridge) 50V 112. 453 k L out /( in m L Q L R k m To analyze LLC behavior easily we set K L Lk L means leakage inductance, L means magnetizing inductance. In normal design we set frequency to 110K Hz to avoid 150K EMI conduction issue and also minimize transformer size. Also set Q to 0.2 and K to 5 for better efficiency and enough hold up time. From the equation of Q we got L m Q RL 0.2 112.453 K L L 32.645 k H K 163.225 H 2 110000 L R L

Transformer Design DC gain of LLC converter f o n V0 M V i and is the resonant frequency and it is equal to 110K Hz means normalized frequency According the graph, maximum DC gain happens when n 0.44 Minimum switching frequency is set as n 0.51 to keep enough margin. So the Minimum switching frequency is f min 110K 0.51 56. 1KHz V in 50V n f f o M 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.5 1 1.5 2 Wn same as calculated above, maximum switching cycle can be calculated as t 1 2 f Flux density B set as 0.5T because the flux can be both negative and positive. Cross-section area A is 30.1mm 2 according to the transformer we choose According to transformer basic operation rule V in t N B A min Full Load Half Load 20% Load 8.913 s N Vin t B A 30turns to avoid saturated.

Transformer Design Leakage Inductance is high Use additional cap to isolate Can not assemble automatically Litz wire to avoid eddy current Fit for higher output power Leakage Inductance is low Use isolated wire to isolate Assemble automatically Thin line to avoid eddy current Fit for smaller output power

Transformer Design Vg_Q1 Vg_Q2 Vp Zone2 ir im Zone2 Zone1 Zone1 is t0 t1 t2 t3 While CCM Zone1 and Zone2 is still almost the same but while DCM Zone1 and Zone2 with obvious different that is why current is more unbalance when DCM.

1. B1 PFC Vout maximum Transformer Design 2. C1 How many transformer in series 3. A3 output voltage 5. A5 output diode Vf for there are 2 diodes in series it should be doubled 4. B3 output current per transformer for dual output design it should be doubled (M, Wn) (0.44, 1.95)

Transformer Design 6. E6 is predicted efficiency 7. B9 operation frequency, higher (M, Wn) means higher core loss and if more than 150K there might be EMI issue lower means bigger transformer 100K~120K would be suggested 8. B10 choose 0.2 is better. Because F10 Lk would be fixed once transformer is selected change B10 to let Lk fit to transformer selected is necessary 9. B11 K is ratio between Lk and Lm bigger means better current balance but lower M (voltage rising rating) choose 5 is suggested (0.44, 1.95)

Transformer Design 10. B13 M_max happen when Wn is 0.44 and add 10%~20% for de rating so choose 0 51 for de-rating, so choose 0.51 (M, Wn) 11. B15 and B16 key in selected transformer data, notice B15 is core B_max *2 because it can operate from B+ max to B- max 12. C20 Choose bigger than B19 to avoid saturated (0.44, 1.95) 13. Key in D28(PFC Vo -2% tolerance -2% ripple) and C29 (system power consumption), choose B27 to key hold up time C30 longer than required

Resonant Capacitor Selection Capacitance calculated by transformer design tool Voltage rating should be 1.2* maximum voltage of resonant capacitor. Ripple current rating should over (output watts/200) * 1.5 Arco R75, R76 or Panasonic ECWH or other Arco R75, R76 or Panasonic ECWH or other capacitor with high ripple current rating is suggested.

DC Blocking Capacitors Capacitance value ~ 1to3%ofC of OUT of each channel Large enough for 10% maximum ripple voltage Small enough to settle quickly Voltage stress: Equal to VOUT to keep margin during single output short. Ripple current stress: 2.5* output current

Output Capacitor selection Voltage rating should be 1.25 * output voltage to keep margin Ripple current on capacitor is 1.2* output current Use ripple current rating as 1 5* output current Use ripple current rating as 1.5* output current for margin

Output Rectifier Selection Reference design D200~D215 Super-fast recovery 2.5* output voltage 1A rating above Trr 35ns Why? Higher efficiency Better current matching at low duty cycle dimming

Feedback, Dimming and Protection Output Current Feedback And Backlight Dimming OVP and OTP UVP

Feedback and Dimming Compensator Pull down output current, feedback and feedback reference Compare to during reference dimming Detect output current

OVP and OTP Detect output voltage Detect temperature Compare to reference Use 2.5V as a base to generate a voltage between 0V and 2.5V

UVP When any single output voltage is lower than 20V UVP triggered When any single output voltage is higher than 80V UVP function enabled Detect output voltage To avoid UVP triggered during dimming, one more circuit to detect if the dimming situation is necessary. In this case, detect output voltage to enable the UVP function is used. While any output voltage is over minus 80V the UVP function is enabled and if there is any output voltage still lowers than 20V the UVP is triggered.

Test Result Reference Design Block Diagram Performance Cross Regulation LED Current Tolerance Efficiency Dimming Waveform Summary

Reference Design Block Diagram TX1 AC Input 90~265V AC-DC PFC DC-DC PWM TX2 TX3 TX4 LED Backlighting (8 channels @120mA; 70~88VDC) ST-BY PWM +12V @3A for Audio-AMP +5V @4A for AD board & System +5VSB @1A for MCU Utility (90~265VAC) TM PFC UCC28051 LLC PWM UCC25600 8 channels @120mA; 70~88VDC) GM PWM UCC28610 Audio-AMP (+12VDC) AD Board (+5VDC) System- MCU (+5VSB) SR Driver UCC24610

Performance Specification: Support to universal 90~264Vac range LED 8 outputs @120mA, 70V~88V, 5Vsb@1A, 5V@4A, 12V@3A Eff 86.1%@90Vac, 89.6%@264Vac Secondary side 160Hz blanking control for dimming 8mm height and 6mmheight for LED magnetic components Board dimension 300mm(L) * 210mm(W) * 8mm(H) LED output common + and LED OVP and UVP

Cross Regulation Cross Regulation Load Condition Output Voltage 5Vsb 5V 12V 5Vsb 5V 12V 20mA 0.5A 0.1A 4.88V 4.88V 13.74V 20mA 0.5A 3A 4.88V 4.88V 11.46V 20mA 4A 01A 0.1A 4.86V 4.84V 13.75V 20mA 4A 3A 4.85V 4.83V 12.5V 1A 05A 0.5A 01A 0.1A 4.87V 4.87V 13.75V 1A 0.5A 3A 4.87V 4.87V 12.05V 1A 4A 0.1A 4.84V 4.83V 13.75V 1A 4A 3A 4.84V 4.83V 12.64V

LED Current LED1 LED2 LED3 LED4 LED5 LED6 LED7 LED8 AVG Voltage 83.6 84.4 85.8 84.2 84.2 80.3 80.6 84.7 100% 122.11 122.04 121.92 122.02 125.55 125.52 123.12 123.09 123.171 90% 109.52 109.44 109.88 109.63 112.86 112.96 110.14 110.12 110.569 80% 97.01 96.93 97.54 97.37 100.18 100.36 97.37 97.41 98.0213 70% 84.63 84.47 85.05 85.19 87.45 87.66 84.6 84.52 85.4463 60% 72.17 72.11 72.66 73.03 74.98 75.08 71.78 71.62 72.9288 50% 59.81 59.68 60.47 61.18 62.37 62.38 59.81 59.81 60.6888 40% 47.48 47.44 48.18 48.86 49.56 49.55 47.24 47.26 48.1963 30% 36.19 36.02 35.92 36.45 37.17 37.21 36.82 36.82 36.575 5 20% 23.92 23.75 23.58 23.86 24.3 24.4 23.85 23.84 23.9375 10% 10.77 10.82 10.77 11.18 11.3 11.38 11.21 11.24 11.0838 5% 4.92 4.94 5.04 5.03 5.11 5.08 4.84 4.84 4.975 2% 1.78 1.77 1.77 1.77 1.82 1.82 1.78 1.78 1.78625 1% 066 0.66 066 0.66 065 0.65 065 0.65 067 0.67 067 0.67 064 0.64 064 0.64 0655 0.655

LED Current Tolerance Tolerance1 Tolerance2 Tolerance3 Tolerance4 Tolerance5 Tolerance6 Tolerance7 Tolerance8 100% -0.8616 % -0.9184 % -1.0159 % -0.9347 % 1.93125 % 1.9069 % -0.0416 % -0.06597 % 90% -0.9485 % -1.0209 % -0.6229 % -0.849 % 2.07224 % 2.16268 % -0.3878 % -0.40586 % 80% -1.0317 % -1.1133 % -0.491 % -0.6644 % 2.20233 % 2.38596 % -0.6644 % -0.62359 % 70% -0.9553 % -1.1425 % -0.4637 % -0.2999 % 2.34504 % 2.59081 % -0.9904 % -1.08401 % 60% -1.0404 % -1.1227 % -0.3685 % 0.13883 % 2.81268 % 2.9498 % -1.5752 % -1.79456 % 50% -1.448 % -1.6622 % -0.3604 % 0.80946 % 2.77028 % 2.78676 % -1.448 % -1.44796 % 40% -1.4861 % -1.5691 % -0.0337 % 1.37718 % 2.82958 % 2.80883 % -1.9841 % -1.94258 % 30% -1.0526 % -1.5174 % -1.7908 % -0.3418 % 1.62679 % 1.73616 % 0.66986 % 0.669856 % 20% -0.07310731 % -0.7833 % -1.4935 % -0.3238 % 1.51436 % 1.93211 % -0.3655 % -0.40731 % 10% -2.8307 % -2.3796 % -2.8307 % 0.86839 % 1.95105 % 2.67283 % 1.13905 % 1.409721 % 5% -1.1055 % -0.7035 % 1.30653 % 1.10553 % 2.71357 % 2.11055 % -2.7136 % -2.71357 % 2% -0.3499 % -0.9097 % -0.9097 % -0.9097 % 1.88943 % 1.88943 % -0.3499 % -0.3499 % 1% 0.76336 % 0.76336 % -0.7634 % -0.7634 % 2.29008 % 2.29008 % -2.2901 % -2.29008 % Inductance tolerance 3% might cause current tolerance 1%

LLC Efficiency Efficiency 0.96 0.94 0.92 0.9 088 0.88 0.86 0.84 0.82 0.8 0.78 0.76 0.74 0.72 07 0.7 Efficiency Data of PFC+ LLC Power Stage from 1% - 100% Dimming 0% 20% 40% 60% 80% 100% Dimming percentage Eff% (PFC+ LLC) Efficiency exclude Stby Power Converter at full load condition ~ 94%

Efficiency 0.9 Efficiency Curve of 150Watt LED TV Back Light Reference Design 0.895 0.89 Eff% 0.885 0.88 0.875 Eff% 0.87 0.865 0.86 80 100 120 140 160 180 200 220 240 260 Vac (v) Vin 90 100 110 120 135 150 180 200 220 240 264 Pin 167.6 166.2 165.1 164.3 163.4 162.7 162.1 161.7 161.5 161.3 161.1 Eff 0.86112 0.86837 0.87416 0.87841 0.88325 0.88705 0.89033 0.89254 0.89364 0.89475 0.89586

Standby Mode Power Consumption Performance @5V/ 0.02A 400 380 360 340 320 Standby Power Losses at 5V/ 0.02A with universal AC input Pin (mw) 300 280 260 240 220 200 Standby Power Losses 180 80 100 120 140 160 180 200 220 240 260 280 300 Vac (V) STBY power 5Vsb 0.02A 02A Vin 90V 100V 110V 120V 135V 150V 180V 200V 220V 240V 264V Pin 216mW 219mW 224mW 229mW 238mW 248mW 267mW 291mW 313mW 342mW 393mW

Summary Two stage will be a market trend for LED-TV backlight power architecture base on cost & performance point of view. Simple design concept- cascading the Ls of transformer at primary side (Multi-Transformers Architecture) to implement the current balancing at secondary side for each channel ideally Achieving <1% tolerance dimming range in reality. Fully utilize the transformer Two-channels common anode LED driven by single transformer. Higher efficiency ~89.6%@ 220Vac/ ~86%@90Vac compare to the traditional 3-stages scheme. (<85%) Exclude the standby converter, the efficiency of PFC +LLC power stage ~94%. Dimming voltage range can work from 1% - 100% and the tolerance of current between each strings less than 1%. Saving the heat sinks for MOSFETs of linear regulators at secondary side. more thinness, cost-saving.

Conclusion Digital TV (DTV) vendors are always challenged to provide consumer reliable product with aggressive price point. Multi-transformer transformer design helps: 1) To decrease parts count so reliability is increased and cost is decreased. 2) Improve efficiency, decreases cost in dealing with thermal issue, thereby increases the life time of the solution. 3) Eliminate MOSFET consuming power, enabling wider output tolerance and more LED failures are acceptable. With these three advantages, we can conclude that multi-transformer design is a better solution.

Flyback Conclusion Flyback + LLC about 92%(LLC95% Flyback Efficiency about 88% Efficiency 86%) Loss on LDO circuit some load condition Loss on LDO circuit No Regulation about +20% / -10% Regulation within +/-5% Minima load for cross regulation 12V/24V load effect when standby 200mA yes Minima load for cross regulation 12V/24V load effect when standby 30mA 65W Flyback cost is higher than 25W Flyback + 40W LLC because of following point 1. 65W Flyback slim transformer cost is high. 2. 65W Flyback require additional linear regulator to keep regulation. 3. Flyback required double time of output cap than LLC 4. Flyback required additional output filter choke 5. Flyback Required Snubber and 800V MOSFET, LLC only need 600V MOSFET According to performance and cost comparison shown above, the use of 5V only standby power and 12V/24V LLC is strongly suggested No

UCC28051 UCC28610 UCC25600 UCC24610 Device Introduction

UCC28051 Transition Mode PFC Controller Slew Rate Comparator for Improved Transient Response LCD-TV Power Board Zero Power Detect to Prevent Over Voltage Conditions under Light Load Over Voltage Protection Open Feedback Protection and Enable Circuits Low Startup & Operating Current 750mA Source/ Sink Peak Gate Drive to Reduce Switching Losses AC-DC Open Frame Power Mid to High Power AC Adapters Line Voltage Follow Over Voltage Protection Slew Rate Comparator 750mA Source/Sink Open Feedback Loop Protection ZCS Detection

UCC28610 QR-GM Cascoded Flyback PWM Quasi-Resonant Green Mode PWM Operation Multiple Modes: Pulse Position Modulation (PPM); Discontinuous Conduction Mode (DCM); Burst Operation Surge Protection is Externally Set Valley Switching is always Engaged Limits Primary and Secondary RMS Currents Fast Latched Fault Recovery for Output OVP, Timed OCP, Over Temperature Protection External Shutdown & Latched Shutdown at MOT Pin Current Sensing for Current Limit uses Rds(on) of Internal FET R MOT C BULK C BULK + - PRIMARY SECONDARY N 1 150V N 2 N B M 1 CG V 0.1uF - BB M1 M 1 N B VGG MOT 10/16V UCC28610 VGG MOTVDD FB 10/16V UVLO VDD FB UCC28610 C G ZCD Valley Control ZCD CL QDCM Control R CL CL M 1 M 2 DRV DRV GND M 2 GND C DD C DD C DD R RCL R CL

UCC25600 Resonant (LLC) Application Circuit 360~400V Vcc DC_OUT Td R T OC SS Gate1 Vcc GND Gate2 1 1 1 1 Programmable dead time Frequency control with minimum/maximum frequency limiting Programmable soft start with on/off control Two level over current protection, auto-recovery and latch up Matching Gate output with 50ns tolerance

UCC24610 SR Controller for 5V Systems Up to 800kHz operating frequency AC/DC 5V Adapters VDS MOSFET-sensing 1.4 ohm sink, 2.0 ohm source gate-drive impedances Micro-power Sleep current for 90+ designs False-triggering g filter; SYNC input for CCM operation 20ns typical turn-off propagation delay Available in 8-pin SOIC and QFN packages 5V Bias Supplies Low Voltage Rectification Circuits Drain-Sense Voltage Source-Sense Voltage Combined Enable Function & Programmable Off-Time Timer) Gate Turn-Off Synchronization Controlled MOSFET Gate Drive Programmable On-Time Timer

Question? Thanks for Your Time!

IMPORTANT NOTICE FOR TI REFERENCE DESIGNS Texas Instruments Incorporated ("TI") reference designs are solely intended to assist designers ( Buyers ) who are developing systems that incorporate TI semiconductor products (also referred to herein as components ). Buyer understands and agrees that Buyer remains responsible for using its independent analysis, evaluation and judgment in designing Buyer s systems and products. TI reference designs have been created using standard laboratory conditions and engineering practices. TI has not conducted any testing other than that specifically described in the published documentation for a particular reference design. TI may make corrections, enhancements, improvements and other changes to its reference designs. Buyers are authorized to use TI reference designs with the TI component(s) identified in each particular reference design and to modify the reference design in the development of their end products. HOWEVER, NO OTHER LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE TO ANY OTHER TI INTELLECTUAL PROPERTY RIGHT, AND NO LICENSE TO ANY THIRD PARTY TECHNOLOGY OR INTELLECTUAL PROPERTY RIGHT, IS GRANTED HEREIN, including but not limited to any patent right, copyright, mask work right, or other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information published by TI regarding third-party products or services does not constitute a license to use such products or services, or a warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. TI REFERENCE DESIGNS ARE PROVIDED "AS IS". TI MAKES NO WARRANTIES OR REPRESENTATIONS WITH REGARD TO THE REFERENCE DESIGNS OR USE OF THE REFERENCE DESIGNS, EXPRESS, IMPLIED OR STATUTORY, INCLUDING ACCURACY OR COMPLETENESS. TI DISCLAIMS ANY WARRANTY OF TITLE AND ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT, QUIET POSSESSION, AND NON-INFRINGEMENT OF ANY THIRD PARTY INTELLECTUAL PROPERTY RIGHTS WITH REGARD TO TI REFERENCE DESIGNS OR USE THEREOF. TI SHALL NOT BE LIABLE FOR AND SHALL NOT DEFEND OR INDEMNIFY BUYERS AGAINST ANY THIRD PARTY INFRINGEMENT CLAIM THAT RELATES TO OR IS BASED ON A COMBINATION OF COMPONENTS PROVIDED IN A TI REFERENCE DESIGN. IN NO EVENT SHALL TI BE LIABLE FOR ANY ACTUAL, SPECIAL, INCIDENTAL, CONSEQUENTIAL OR INDIRECT DAMAGES, HOWEVER CAUSED, ON ANY THEORY OF LIABILITY AND WHETHER OR NOT TI HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, ARISING IN ANY WAY OUT OF TI REFERENCE DESIGNS OR BUYER S USE OF TI REFERENCE DESIGNS. TI reserves the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All semiconductor products are sold subject to TI s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI s terms and conditions of sale of semiconductor products. Testing and other quality control techniques for TI components are used to the extent TI deems necessary to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily performed. TI assumes no liability for applications assistance or the design of Buyers products. Buyers are responsible for their products and applications using TI components. To minimize the risks associated with Buyers products and applications, Buyers should provide adequate design and operating safeguards. Reproduction of significant portions of TI information in TI data books, data sheets or reference designs is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional restrictions. Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards that anticipate dangerous failures, monitor failures and their consequences, lessen the likelihood of dangerous failures and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use of any TI components in Buyer s safety-critical applications. In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI s goal is to help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and requirements. Nonetheless, such components are subject to these terms. No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties have executed an agreement specifically governing such use. Only those TI components that TI has specifically designated as military grade or enhanced plastic are designed and intended for use in military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components that have not been so designated is solely at Buyer's risk, and Buyer is solely responsible for compliance with all legal and regulatory requirements in connection with such use. TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of non-designated products, TI will not be responsible for any failure to meet ISO/TS16949. Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265 Copyright 2014, Texas Instruments Incorporated