AC-DC LCD TV Power Architecture and LED Backlight

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1 AC-DC LCD TV Power Architecture and LED Backlight

2 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 NCP6 Quasi Resonance Valley lock out Flyback Converter with NCP79 ECO Standby SMPS Solution with NCP05A 46/47 Backlight solution LIPS Inverter Edge LED Driver Conclusion

3 LCD-TV Shipments by Size Source: Displaysearch 2Q 09

Source: Sharp Proposed ENERGYSTAR TV regulations (V4.

4 Power Reduction Trend Regulatory reduce power consumption in active and standby mode New technologies focused on improving efficiency Source: Sharp Proposed ENERGYSTAR TV regulations (V4.0) will lower average power targets Power consumption reduction ~ - 50% over 2 years

5 Proposed ENERGY STAR rev4.0 Standards Very few LCD-TV pass proposed new standard, most are Samsung LED Target Effective Date: May 200

6 LCD-TV LED Backlighting Source: DisplaySearch July 2009 LED TVs is forecast to grow to 20-2% (~64 M#) by 202

Comparison of LED LCD TV Backlight Options LED driver Edge-lit LED BLU High voltage Boost, buck, linear with Vf adjustment Direct-type LED BLU Boost or

Cost down of system Slim LCD TV System Noise & EMI Using lots of external components (Inductor, capacitor, diode) Deep blacks, better contrast Local

7 Comparison of LED LCD TV Backlight Options LED driver Edge-lit LED BLU High voltage Boost, buck, linear with Vf adjustment Direct-type LED BLU Boost or Buck plus Multi-channel linear Merit Concerns High Power Efficiency Good system reliability independent LEDs performance. Cost down of system Slim LCD TV System Noise & EMI Using lots of external components (Inductor, capacitor, diode) Deep blacks, better contrast Local dimming Scanning for higher frame rate Low power consumption Complex signal processing Thermal limitations High system cost due to number of LEDs and # of Drivers Picture artifacts Edge LED > 90%?

8 Power Architectures Remain Varied PFC CRM Interleave FCCrM CCM W Signal Power Flyback Resonant HB 0 80 W ECO Standby < 5 W Backlight Power Flyback / Resonant HB 24V / 50V+ for LED HV-LIPS for CCFL / EEFL W Traditional 24 V Backlight and HV-LIPS approach Thin TV design impacts solutions choices as well

9 2 HV-LIPS Reference Design For 2 (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 NCP607 as CrM PFC controller NCP5 or NCP29 as Flyback with low power standby mode LX650 Microsemi Backlight controller Full Bridge High Voltage Inverter without High Side Driver (discrete circuit) Jin balance solution

10 2 HV-LIPS LCD TV Block Diagram

11 HV-LIPS LCD TV Complete Solution 2 CCFL 75 mm x 0 mm x 25 mm All-in-one board with current balancer Green Point Reference design documentation: 60-D.PDF

12 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 st phase: < mm 2 nd phase: < 8 mm

13 46 LCD TV Power Block Diagram

14 46 LCD TV Power Solution Unit (PSU) Low Profile design < mm / 7.5 mm total

15 46 LCD TV PFC Solution Up to 00 W Interleaved Frequency Clamp CrM PFC Better EMI and EMC Lower I rms for output C Better for SLIM design Standard parts (= 2 CrM) New controller NCP6 Easy SLIM narrow range version Interleaved FCCrM PFC for > 200 W & SLIM design

16 PFC Summary

17 BD 46 LCD TV PFC Schematic GBU806 D N5406 Gnd_Lug CN L 50uH L2 200uH nc * 7 L2Q D2 MUR550APF RT NTC 2R5 PFC_OUT C Y nf C4 Y nf C5 X2 00nF 275V CFS L4 8.7mH CFS28 2 C 0.47uF 450V C2 0.47uF 450V R M R2 M R8 M R9 M R5 M * 2 L 2 200uH LQ2 * * 7 Q STP9NK50ZFP D5 MMSD448 2 R42 0K Q BC808-25LT R D MUR550APF Q2 STP9NK50ZFP C7 D6 MMSD448 0nF 500V R4 Q4 0K BC808-25LT R R4 M R5 M R0 M R M R24 K5 C8 + 68u 450V C6 + 68u 450V PFC_OUT CN S Backlight Input Power and Signal 4 L5 8.7mH R20 M R28 M D8 MMSD448 C NA R9 NA C0 NA R0 24K J06 INSTALL 2 C2 X2 uf 275V R W 5% R K R6 22K R2 K ZCD_0 O_UVP FB_PFC R7 50K R2 50K R8 50K R22 50K R9 50K R2 50K FB_PFC R4 22K ZCD_ 2 4 IC ZCD2 FB Rt OSC NCP6 6 ZCD 5 PFC-OK 4 DRV GND R27 47k R26 2K2 R25 5K VCC4 PFC-OK 4 2 RELAY RELAY2 SW RELAY SPST BO_PFC C2 220n R29 20K C7 nf R 20K C8 220p R4 270K C9 220n C 680n R 9K R4 0K Vcontrol Vcc Freq-Fall Back DRV2 BO Latch OFF OVP/UVP CS O_UVP C22 NA R5 0 C5 00n C20 0n + C6 0u 50V Q6 BC856ALT R7 K 2 R8 K 2 2 Q5 BC856ALT PC00A POWER_BOOST R6 0k D N4007 SFH87A F FUSE 6A-250V F2 4R7 W Standby_supply _VAC_INPUT LINE_NEUTRAL RV5 TVR047KSY + C24. uf 400V + C25. uf 400V L FG FG FG N CN00 4-W05ST

18 46 LCD TV QR Flyback Solution Flyback converter Up to 70 W max Up to output with 4 A Max Quasi Resonance Flyback Converter Reduced EMI Best safety behaviors New NCP79 controller Valley-lockout system Variable frequency mode for ultra low power mode Over current protection with auto recovery internal timer

19 46 LCD TV PWM Fixed F Flyback Solution PWM Fixed Frequency Flyback converter 50 khz Fixed frequency Allow natural CCM New NCP252 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 46 LCD TV Flyback Schematic T PFC_OUT R252 K 2W R25 K 2W C200 0n 500V D20 * N497 do4d * 2 C207 P + D207 N C208 P 470u 6V N + 470u 6V R205 K R k D20 MMSD448 C20 68p R2 K PC0B SFH87A 4 C2 n CS C22 220p PFC-OK R249 8K2 R k ZCD FB CS GND IC200 NCP79 CT 8 BO 7 VCC 6 DRV VCC4 R24 0k 5 R27 27 C25 00n C26 + 0u 50V R C2 0p 00n D206 MMSD448 C24 VCC CS PC0A SFH87A IC20 ZD200 MMSZ5T 2 2 TL4BCLPRA R2 470 R28 K D205 BAV2 + C27 47u 25V D209 MMSD448 2 Q204 BC808-25LT R2 2K49 R227 K 2_5VREF R207 R226 C20 4R7 Q20 STP5NK70ZFP 470nF K R220 47k R2 R22 V R22 Gnd_Lug 0.47R 2W CN40 6K2 6 5 C28 00p KV 6K9 * C225 Y nf * * R255 0M 2W R24 2K2 VS2 VS D26 MMSD448 MMSD448 R242 2K2 to220 MBRF20L80CTG Q202 MJD200 DPAK 2 to220 ZD20 MMSZ6V8T D20 R R MBRF20L80CTG D29 + P N D25 MMSD448 + C u 6V + C29 470u 6V R28 0K P N P + C22 470u 6V C22 470u 6V R27 0K N P N R26 4K7 2 P C u 6V N Q207 BC858ALT D22 MMSD448 P + + C u 6V D27 P C u 6V V2 N N MMSD448 + V2 2 Q20 BC858ALT V 2 Q205 BC858ALT VS-Stby L20 0uH 2 R208 2K2 L202 0uH 2 R29 2K2 VS2 VS VS2 VS D208 MMSD448 R20 K Regulation D2 MMSD448 R222 K Regulation R22 K R22 K CN S 2 CN S P N P N + C u 6V + C u 6V VS2 VS Backlight controller supply to Backlight board Flyback power to Signal processing and Audio board R228 K Regulation

21 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 = 4 W.75 A at 42.7 khz V max = 572 V Bottom Trace Vin = 400 Vdc Pout = 70 W 2.62 A at 9 khz V max = 68 V Valley lock-out is a Key improvement of QR mode

22 ECO Standby SMPS Solution () Dedicated 5W ECO Power Standby SMPS P in < 90 mw for P out = Vac Integrated High Voltage switcher NCP05A (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 ECO Standby SMPS Solution (2) Standby relay Disconnect all parasitic standby load (~ Vac) Directly controlled by TV µp Optional ECO ON / OFF switch Low cost 2A / 0V non-isolated switch OFF mode: P in < 20 mw by no 20 Vac ECO switch provides ON/OFF without Mains switch

24 ECO Standby SMPS efficiency Efficiency (%) Efficiency / 20V Efficiency / 20V Output Power (W) OFF mode / no load: P in < Vac 20 Vac) Standby / 40 mw Out: P in < Vac 20 Vac)

25 ECO Standby SMPS Waveforms Drain Voltage and Current of NCP05A Switcher 200 V/div & 200 ma/div For 5 V & A = 5 W Output Left: Hysteretic Burst mode (00 µs/div) Right: Detailed cycle (4 µs/div) Top Trace: 90 Vac Middle Trace: 20 Vac Bottom Trace: 264 Vac

26 ECO Standby SMPS Schematic Standby_supply Q0 BC808-25LT 2 VCC4 R00 00K /4W D04 VCC2 MMSD448 D05 C00 C0 220p 400V 0p KV D0 N497 VCC D02 R20 0 VCC T D MBR PC00A SFH87A R04 0K L00 2 0uH + C02 R0 470µ 6V K R02 0K C06 00 n.25vref R05 IC0 0K TLV4ASN P N 2 J00 INSTALL 2 P N VS-Stby + C0 47µ 25V 2 CN S ON-OFF Switch "Optional" R 4K7 MMSD448 BAV2 PC200B SFH87A 4 R4 2K2 HV Barrier D09 MMSD448 V VS-Stby Regulation RELAY D08 MMSD448 STANDBY R0 8.2K RELAY2 D0 MMSD448 ZD0 MMSZ5VT VS PC00B 4 C04 0u 25 V + IC00 NCP05P44G VCC GND 8 2 Control in GND 7 + C05 47u 25 V R PC200A SFH87A 2 R07 4.7K D0 MMSD448 D06 MMSD448 R08 4.7K R0 K D07 R09 0K R 0K 2 Q00 BC858ALT R2 K ZD02 MMSZ5T VS2 SFH87A GND Q02 MMSD448 Q0 R5 K 4 NC Power Drain 5 BC848ALT R7 4.7K R6 K BC848ALT R8 470 C07 0nF VS-Stby R9 22K 4 PC00B SFH87A POWER_OK VS-Stby CN S POWER_OK Standby power and signal To Signal processing board STANDBY

27 46 Flat TV PSU - Backlight Interface Interconnection on Power to any Backlight solutions 400 Vdc / 200 W PFC OK 5 V and 2 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 46 LIPS Inverter Higher power LCD-TVs With extension to 40/42 or 52 /55 for both CCFL or EEFL Follow on of 2 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 < mm Microsemi Backlight controller LX650 ON Semiconductor IC s 2 High Side Drivers NCP5 single signal driver transformer Low profile design < mm on top of PCB

29 46 LIPS Inverter Block Diagram LIPS - High Voltage Back-light Inverter Full Bridge Inverter 2 x High Side Driver NCP5 OFF in Stand-by I Lamp regulation OCP, OVP Current sensing Current balancing Board Open lamps protection CCFL PWM PWM 2 Back-light Controller LX650 ON/OFF, Dimming,Synchro CrM Interleaved PFC NCP6 400 Vdc OFF in Stand-by Relay Bias QR Flyback SMPS NCP79 OFF in Stand-by 2 Vdc 5 Vdc Vdc Audio Power Good St-by / ON LCD TV Signal processing and Audio amplifiers Mains Input Vac Stand by SMPS NCP05A ON/OFF 5 Vdc- Stand-by Power (PFC + Flyback + Standby SMPS)

30 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 NCP97 New New LED driver controller CAT4206 Low profile design < 8 mm on top of PCB (< 2.5 mm total)

31 Multiple LED Linear Drivers with CAT4026 Up to 6 channels with linear bipolar transistors Linear: V f monitoring and supply modulation & control Dedicated SMPS to support output voltage modulation

32 46 Linear Edge LED Driver TV Block Diagram Dedicated SMPS for Backlight with Modulated output voltage

33 46 Linear LED Driver Backlight Solution Special technologies PCB size: 250 mm x 65 mm Ultra SLIM design < 8 mm / 2.5 mm total

34 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 coil for OCP Drawbacks: cooling insulation Benefits: insulation

35 Resonant Inductance Location? External inductance Internal leakage inductance Benefits: flexibility EMI use resonant coil for OCP Drawbacks: cooling insulation Benefits: insulation cooling One component Drawbacks: flexibility EMI + stray flux window utilization External resonant coil is better for ultra slim design

36 Push-pull configuration Secondary Rectification Bridge rectifier Benefits: voltage drop Single diodes Drawbacks: secondary winding matching window utilization Higher voltage rectifiers Benefits: one winding Lower voltage diodes Matching Drawbacks: Higher losses Bridge rectifier is better for HV output applications

37 NCP97 - LLC Stage Controller Features: - operation from 50 khz up to 500 khz V driver - Startup sequence via an externally adjustable softstart - 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 NCP97 is cost effective and highly safe solution

38 New OCP Implementation Adjustable delayed fault Short circuit protection with frequency shift New Double phase current information from auxiliary winding of resonance coil Res. Coil aux. winding provides accurate and fast OCP

39 Output Voltage Modulation CAT4026 sinks current from FB divider to increase output 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 HB LLC Schematic for Linear LED Driver

5 A/div) Middle: Primary current 2 A/div Bottom: Output voltage ripple 2 V/div (20 Vdc)

41 HB LLC Waveforms Strong load variation (0 to 00%) on HB LLC with 00 Hz dimming Traces: Top: Output current from 0 to A (0.5 A/div) Middle: Primary current 2 A/div Bottom: Output voltage ripple 2 V/div (20 Vdc) Top picture: 50% dimming HB LLC works in Burst Up to V peak ripple on V out Bottom picture: 5% dimming HB LLC works in Burst < 0.5 V peak ripple on V out

42 Edge-LIT LED Backlighting Trends LED Light bars vary in configuration Single LED Strings of High Power (~ 200 V+, 00 ma+) Multiple LED Strings (up to 4) of Lower Power (~ 00 V+, 50 ma+) LED Driver solutions must handle from 4 to 6 channels

43 Existing Large Panel Backlight Solution Loosely ~00V For each LED channels! Advantage: Independent Channel Efficiency and LED-Fault handling Loosely regulated input supply Drawback: Cost and Complexity

has a Dedicated Driver IC + inductive DC/DC boost + switch 6

44 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 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

46 Multi-channel Linear Edge-Lit Solution 6 channel configuration shown LED-Anode : dynamic adjustment LED Cathode regulation ~ V LED Cathode OVP Fault diagnostics External power devices (low θja)

47 Multi-channel Linear Edge Driver Schematic Connection to the 6 Edge LED segments OVP UVP DPAK or TO220FP Power stage Current sense

48 Optimized Dynamic LED-Anode Control EFFICIENCY 00% 95% 90% 85% TYPICAL EFFICIENCY 200V 00V DISSPATION [WATTS] 'LINEAR' POWER DISSIPATION 6ch: 200V, 00mA (20W) 2ch: 00V, 50mA (60W) 80% 0% 5% 0% 5% 20% LED STRING MISMATCH [Pk-Pk] 0 0% 5% 0% 5% 20% LED STRING MISMATCH [Pk-Pk] Efficiency depends on LED string matching 200V LED strings (with 0% mismatch) delivers ~ 94% efficiency Thermal power dissipation levels : ~ 5 to 0 watt range V modulation & control to limit overall Power dissipation

49 LED Channel Current Matching VARIATION vs BASE CURRENT 0.6%.0% CHANNEL MATCHING % 0.4% VARIATION % 0.2% 0.0% -0.2% -0.4% -0.6% MATCHING % 0.5% 0.0% -0.5% Ch Ch2 Ch Ch4 Ch5 Ch BJT BASE CURRENT [ma] -.0% 0.6% VARIATION vs LED CATHODE CHANNEL VARIATION %. 0.4% 0.2% 0.0% -0.2% -0.4% -0.6% CATHODE VOLTAGE [V] Initial channel matching tolerance ~ ± 0.5% Variation with BJT Base current : < 0.25% Variation with Cathode to 0V : < 0.5% Overall Channel matching less than ± 2% Very good current matching < +-2%

50 Optimized Wide PWM Dimming Range CURRENT % [FSB] 00% 0% % 0% BRIGHTNESS vs PWM DUTY 0% % 0% 00% PWM DUTY CYCLE No concept limitation for very short ON time CAT4026 Linear Driver is optimized for PWM dimming Strong power variation managed directly by SMPS Down < % for 400Hz PWM dimming

51 Edge LED Linear Backlighting Summary Provides reduced total solution cost VF monitoring minimizes & optimizes power dissipation Minimizes EMI Offers competitive 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

52 Conclusion Complete roadmap of LCD TV solutions 2 LIPS A cost optimized solution for CCFL from 26 up to Power Power for any type of Backlight from 40 up to 55 < or 8 mm 46 LIPS < 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

53 For More Information View the extensive portfolio of power management products from ON Semiconductor at View reference designs, design notes, and other material supporting the design of highly efficient power supplies at

300 W High performances SLIM TV Power solution

300 W High performances SLIM TV Power solution TND0/D Rev. 0, June 00 00 W High performances SLIM TV Power solution Jean-Paul Louvel CCPG - LCD TV System Applications 00 ON Semiconductor Disclaimer: ON Semiconductor is providing this reference design