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Novel Driver Solution for LED Lighting 2015.4.17. 1. Outline. Solution for Dimmable MR16 Application PSR PFC CV controller for 2-stage Application. 2019/12/20. 2. Outline. Solution for Dimmable MR16 Application PSR PFC CV controller for 2-stage Application. 2019/12/20. 3.
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Novel Driver Solution for LED Lighting 2015.4.17 1
Outline • Solution for Dimmable MR16 Application • PSR PFC CV controller for 2-stage Application 2019/12/20 2
Outline • Solution for Dimmable MR16 Application • PSR PFC CV controller for 2-stage Application 2019/12/20 3
Dimmers and Their Limitations Leading edge dimmer • Leading edge dimmers must never be used with a capacitive load extremely high instantaneous current when turning on • Cheap and easy to get
Dimmers and Their Limitations Trailing edge dimmer • Trailing edge dimmers are not supposed to work with an inductive load • A MOSFET and potentially a commercial IC are needed. Relatively expensive
Electronic Transformers Capacitive load • The term "electronic transformer" is really a misnomer - it is actually a switch mode power supply (SMPS). • A minimum load current is required to assure electronic transformer's functionality
Compatibilityof Dimmer and E-Transformer Electronic Transformer TriAC Dimmer
Compatibilityof Dimmer and E-Transformer TRIAC Current ET Input Current ET Output Voltage TRIAC Trigger Voltage ET behaves as a capacitive load to TRIAC
Dimmable MR16 LED Driver Dimmer Electronic Transformer Rectifier SY8726A 12V AC AC Input
SY8726A Specifications Pinout
Schematic Diagram Boost+buck Topology Startup bleeding
Efficiency with Dimmer and E-transformer Philips ET-E60 Full Angle
Typical Waveforms CH1(blue) : VBOOST_IN CH2(cyan) : VBOOST_OUT CH3(pink) : IBOOST_L CH4(green): IBUCK_OUT IBUCK_OUT=500mA VIN=220VAC
Outline • Solution for Dimmable MR16 Application • PSR PFC CV controller for 2-stage Application 2019/12/20 16
PSR CV eliminating opto-coupler SY5018 Bridge Flyback, PFC, CV HF Buck, CC 2019/12/20 17
Features • Constant ON time to achieve high PF • PSR eliminating opto-coupler • QR-mode operation • Excellent short output protection • Good transition performance • Advanced design on fast start up 2019/12/20 18
Constant ON time to achieve high PF Constant on time to achieve high PFC As long as tON is fixed, although tS(t) is varied with t, high power factor is achieved.
PSR eliminating opto-coupler Primary side control VREF is voltage reference, NS is secondary turns of transformer, VSEN is voltage feedback.
QR-mode operation QR mode is adopted to decrease switching loss, it’s achieved by delay after VSEN detects zero-crossing signal In order to ensure valley turned ON, t3 should be around 2 tDelay
Excellent short output protection Short output zoom in When output is shorted, voltage of VSEN is nearly zero, and IC will work at max toff mode. After 32 times max toff , IC hiccup.
Good transitionperformance Better performance on Transition IC set VFB,HIGH above VREF IC set VFB,LOW below VREF When VSEN touch VSEN,HIGH, IC work at Max toff mode to decrease output energy When VSEN touch VSEN,LOW, IC work at Max Ipeak to expedite output energy Output voltage could be clamped at VFB,HIGH and VFB,LOW when transition
Advanced design on fast start up Between 0~t1, IC work at peak current mode to speed up the output voltage rise. After VSEN higher than VFB,LOW, IC work at constant mode to realize high PF. AS the supply voltage at the point VFB,LOW is already enough to supply IC, so smaller capacity of CVIN is needed, so, start up could be very fast.
Start up & Shut down VIN=90Vac Start up time=450mS VIN=110Vac Start up time=330mS CH1(Blue):VVIN CH3(Pink):VOUT CH4(Green):IOUT
Load Transition VIN=110Vac Over shoot15% Under shoot20% Full load Full load Null load Null load VIN=220Vac Over shoot15% Under shoot20% Full load Null load Null load Full load CH3(Pink):VOUT CH4(Green):IOUT
Silergy Silicon Energy-Powering the Future Total power solution provider targeting energy conservation Thanks! Any enquiry please contact me by larry.huang@silergycorp.com 2019/12/20 31