1. Novel Driver Solution for LED Lighting 1

2. Outline Solution for Dimmable MR16 Application
PSR PFC CV controller for 2-stage Application
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3. Outline Solution for Dimmable MR16 Application
PSR PFC CV controller for 2-stage Application
2017/4/22 3

4. 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

5. 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

6. 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

7. Compatibility of Dimmer and E-Transformer
Electronic Transformer
TriAC Dimmer

8. ET behaves as a capacitive load to TRIAC
Compatibility of Dimmer and E-Transformer
TRIAC Current
ET Input Current
ET Output Voltage
TRIAC Trigger Voltage
ET behaves as a capacitive load to TRIAC

9. Dimmable MR16 LED Driver Electronic Transformer Rectifier SY8726AAC
Input
Electronic
Transformer
Rectifier
SY8726A
Dimmer
2017/4/22

10. SY8726A Specifications
Pinout

11. Schematic Diagram
Boost+buck Topology
Startup bleeding

12. Efficiency with Dimmer and E-transformer
Philips ET-E60 Full Angle
VIN(VAC)
Pin(W)
Vout(V)
Iout(mA)
Efficiency(%)
200
8.47
12.22
491
70.80%
220
8.48
12.19
490
70.43%
240
8.53
12.18
492
70.25%

13. Typical Waveforms IBUCK_OUT=500mA VIN=220VAC
CH1(blue) : VBOOST_IN CH2(cyan) : VBOOST_OUT
CH3(pink) : IBOOST_L CH4(green): IBUCK_OUT
VIN=220VAC
IBUCK_OUT=500mA

14. Dimming Curve

15. Compatibility List P O Compatibility Siemens 5UH8222-3NC01
OSRAM
Philips
ET-A60
HTM-70
ET-S60
ET-E60
Leading
Siemens 5UH8222-3NC01 P
Siemens 5UH8622-3NC01
Siemens 5UH8722-3NC01
TCL K5/M2 O
TCL VM2
TCL A8/426U
Schneider EV51RD400
Schneider K31RD400
Philips Q2-2-M1
Panasonic WMS549
CDN D8-TG01
Trailing
Clipsal 32E450UDM
Sal SDA 450
Hager Blu V1454
Siemens 5TC8 284
Bosch 6513 U-102

16. Outline Solution for Dimmable MR16 Application
PSR PFC CV controller for 2-stage Application
2017/4/22 16

17. PSR CV eliminating opto-coupler
SY5018
Bridge
Flyback, PFC, CV
HF Buck, CC
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18. 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
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19. 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.

20. PSR eliminating opto-coupler
Primary side control
VREF is voltage reference, NS is secondary turns of transformer, VSEN is voltage feedback.

21. 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

22. Excellent short output protection
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.

23. Better performance on Transition
Good transition performance
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

24. 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.

25. Design Example

26. Circuit Diagram

27. Load Regulation VIN=90V VIN=110V VIN=220V VIN=2640V IO(A) VO(V) 0.80
49.2
49.3
49.5
0.70
49.6
0.60
49.4
0.50
0.40
0.30
0.20
49.8
49.7
0.10
50.0
0.05
49.9
0.00
50.1

28. Steady Performance VIN(Vac) VO(V) IO(A) PIN(W) PF THD(%) EFF(%) 90
49.3
0.8
44.53
0.996
7.4
88.57%
110
43.91
0.994
9.1
89.82%
132
49.4
43.61
0.992
8.8
90.62%
176
49.5
43.40
0.983
91.24%
220
49.6
43.49
0.968
11.5
264
49.7
0.966
10.6
91.17%

29. Start up & Shut down VIN=90Vac Start up time=450mS
CH1(Blue):VVIN CH3(Pink):VOUT CH4(Green):IOUT

30. CH3(Pink):VOUT CH4(Green):IOUT
Load Transition
VIN=110Vac
Over shoot 15%
Under shoot 20%
Full load
Null load
Null load
Full load
VIN=220Vac
Over shoot 15%
Under shoot 20%
Full load
Null load
Null load
Full load
CH3(Pink):VOUT CH4(Green):IOUT

31. Thanks! Silergy Silicon Energy-Powering the Future
Total power solution provider
targeting energy conservation
Any enquiry please contact me by
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