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LED Lighting Driver IC Introduction. Robin Liao January 2011. http://www.richtek.com/LED. Contents LED Lighting Driver IC Overview AC input to constant current LED driver -- Isolated AC input to constant current LED driver -- Non-isolated DC to CC Solution Applications Selection Guide .
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LED Lighting Driver IC Introduction • Robin Liao • January 2011 http://www.richtek.com/LED
Contents • LED Lighting Driver IC Overview • AC input to constant current LED driver -- Isolated • AC input to constant current LED driver -- Non-isolated • DC to CC Solution • Applications • Selection Guide
LED Lighting Driver IC Overview E26/E27/E17, T5/T8 Par30/Par38, Street light Isolated AC/CC GU10, E26/E27/E17 T5/T8, Par30/Par38 Non-isolated LED Lighting With ET MR16, AR111 DC/CC Street light, car light, desk light, freeze light, projector Emergency light Without ET
AC Input Solution -- Isolated • Application • E27, GU10 …. Bulb, Par 30, Par 38 • T5, T8 …. Light bar, Freeze light • Street light, Desk light… • Richtek advantage • High-precision constant current control to limit current accuracy in +/-5% range on mass production. • Small package and high integrated solution with less external components to fit into a small bulb or light bar • Very low quiescent current • Dimming on secondary side to provide better accuracy
Secondary side CC/CV controller AC to CC – Isolated – secondary side CC/CV controller & dimming RT8456 Single channel CC/CV controller RT8457 Single channel CC/CV controller with dimming RT8454 Multi-channel CC/CV controller with dimming • Easily work with any kind of primary side topology. • Provide high precision LED current. • LED current accuracy does not vary with the accuracy of transformer. • OVP support
RT8456 Secondary-side constant Current Controller • Secondary side LED current regulation • Support LED voltage up to 45V • High accuracy LED current threshold control over wide input voltage and temperature range • 0.6mA operation current • Programmable LED current through 60mV sense resister • Programmable OVP • Easily connected to different kinds of primary side solutions • TSOT 23-6
RT8457: Dimmable secondary side constant current controller • LED voltage up to 45V • Support Triac dimming, PWM dimming, analog dimming • High accuracy LED current threshold control over wide input voltage and temperature range • Programmable LED current through 60mV sense resister • Programmable OVP • Easily connected to different kinds of primary side solutions • SOP-8 Dimming Input
RT8454 AC-CC 6-Ch Current Regulators • Vcc up to 50V • Programmable channel current • 3% current sense amplifier input offset • Easy dimming • Programmable soft start and OVP • Automatic detecting unconnected AND/OR broken channel to avoid output over voltage • Vcc under voltage lockout and Thermal shutdown • One LDO controller embedded
AC Power Lines AC to DC Primary Side Circuit Vaux Opto-Coupler Application Tip: RT8454Channel Number Extension
Applications: Isolated E26/27, T5/T8, PAR30/38….. • Primary side solution example • Flyback: R7912 (MOS inside) R7732(MOS ext.) • Low PF, small output current ripple, good efficiency, good for no-PF requirement condition. • Valley-fill PFC+Flyback • For small power (<10W), PF at 0.7~0.9 range. Small output current ripple, good for small power and PF>0.7 application. • Active PFC+Flyback • High PF (>0.9), lower efficiency, small output current ripple, good for high power design. • PFC single stage • High PF (>0.9), low cost, need big output cap to reduce current ripple. Good for small power, low cost design. • LLC • High efficiency, high cost. Good for high power, high performance design. • Primary side constant current : R7710 • Current accuracy is suffered from transformer accuracy. Good for current accuracy <+/-10% application
Applications: Isolated E26/27, T5/T8, PAR30/38….. • Secondary side solution • RT8456, RT8457, RT8454 can work with any kind of primary side topologies and become constant current LED drivers except (6) • Maintain current accuracy at +/-5% independent of the variation of transformer • Non-dimmable: Primary side + RT8456 • Dimmable: (bleeder)+ Primary side + RT8457 • Support Triac dimming with external bleeder added • Support PWM, analog, wireless… dimming on secondary side with accurate current control. • Using MCU for Traic dimming can provide the best compatibility of dimmer.
AC-CC non-isolated product roadmap AC to CC – non-isolated RT8458 High-side buck CC LED driver RT8459 High-side PFC buck CC LED driver High-side PFC inverting buck-boost CC LED driver RT8460 MOS inside RT8469 RT8468
RT8458 floating buck LED driver for non-isolated application • Unique self-biasing floating buck driver topology • True average LED current sense • High efficiency (>90% possible) • Cheap and simple external components • Very wide input voltage range (16V~400V or higher) • Stable LED current over wide input voltage range • Works with standard series drum choke inductors • Support OVP & OCP • Small PCB to to fit GU10, E17….. The best way to drive LEDs from AC power input!!
Three RT8458 applications • Typical application • Advantage • Very good line regulation. LED current variation between 110V/220V AC input is minor. (<+/-2%) • Small input/Output cap • Simple external components • Good for application do not need PFC. • Disadvantage • Low PF (About 0.6) • Valley-fill PFC+RT8458 • Advantage • PF at 0.7~0.9 for low power application (<10W) • Good for small power, PF>0.7 design • Disadvantage • Big cap for high power or high PF application. • Active PF + RT8458 • Advantage • High PF (>0.95) • Good for high power, high PF design • Disadvantage • Higher cost • Lower efficiency
RT8458 typical application circuit OVP option Vout>31V EMI improvement
RT8458 efficiency vs. LEDs LED current=350mA
RT8459 High PF, floating buck LED driver for non-isolated application • Unique self-biasing floating buck driver topology • True average LED current sense for high PF application • Cheap and simple external components • Very wide input voltage range (16V~400V or higher) • Stable LED current over wide input voltage range with high PF support • Works with standard series drum choke inductors • Support OVP & OCP • Small PCB to to fit GU10, E17…..
RT8459 test result with universal input ** Good line regulation for universal input with high PF support ** NOTED: Higher output current ripple & big output cap. for PFC single stage design
How to choose the driving topology? NO RT8458 typical application Need PFC? Small output current ripple? NO RT8459 typical application Valley-fill PFC+RT8458 good for small power, PF in 0.7~0.9 Active PFC + RT8458, good for high power design or PF>0.9
Richtek’s Product -- DC to Constant Current RT8450B RT8453B RT8470 RT8471 Converter RT8482 RT8452 RT8480 RT8488 Controller • Application • MR16, AR111 • Street light, Desk light, Freeze light • Car light, Projector lamp • Solar lighting, Emergency light
Richtek’s Product -- DC to Constant Current • Richtek advantage • Cover wide input/output voltage range and support different kinds of topology include buck, boost, buck-boost, SEPIC • Accurate output current over wide temperature range • Stable output current vs. input/output voltage change • Easy Dimming : Analog, PWM or PWM Converting to Analog with One External Capacitor, Triac dimming • Support high-speed PWM dimming up to 50kHz • Better reliability with bipolar process • Cost competitive
Applications: MR16 • Major solutions • RT8470 low cost solution • Lowest cost solution • About 70% Electronic Transformer (ET) compatibility • Different brightness with different ET connected • Very popular in China • RT8453 high ET compatibility solution • Very high ET compatibility • Keep same brightness with different ET connected • Special applications • RT8453 dimmable solution • Dimmable with minor cost added from the previous solution • Same performance as the previous solution without dimmer connected • ET limited • With selected ET, about 50% dimmer can dim pretty well • RT8453 non electrolytic cap solution • High ET compatibility with square wave output • RT8453 three-step dimming • Support three-step dimming with three-step dimming controller added • Use ON/OFF break to switch between three steps
MR16—RT8470 Buck CH1: Vin CH4: Iin CH1: LED voltage CH4: LED current Average LED current will be different with different ET connected
Application: RT8453 MR16 • Excellent electronic transformer compatibility • High efficiency, stable output LED current • Support Triac dimming with selected ET and Dimmer but no extra cost added • No flicker with most of the ET
Application: RT8453 MR16 CH1: Vin CH4: Iin CH1: LED voltage CH4: LED current Very stable LED current with different ET connected
PFC + AC2DC Primary Side Circuit RT8454 AC Power …. Vbase 6 CHs Opto Vaux 6 Current Sources FBx6 MCU Gx6 …. Dim CSx6 Other Control Signals NTC Sense LED Temp. Applications: Street Light (I)
DC 12V~48V AC Power RT8488 PFC AC2DC …. Vaux Gate (Either one or both) Gbias 6 CHs MCU Sense LiFePO3 Batteries Dim 6 Current Sources Other Control Signals FBx6 NTC Solar Cell Gx6 …. Sense LED Temp. CSx6 Applications : Street Light (II)
DC 12V~48V AC Power RT8480 PFC AC2DC Up to 40xLEDs (160V) Vaux Gate (Either one or both) Gbias Sense LiFePO3 Batteries MCU Dim PWMO Dimming Solar Cell Other Control Signals Thermal Feedback IFB Current FB NTC Sense LED Temp. Applications : Street Light (III)