Reference Design Report for a 21W (42V/0.5A) LED Driver Using SFL900

Reference Design Report for a 21W (42V/0.5A) LED Driver Using SFL900 Specification Application 90-264VAC Input; 42V/0.5A output LED Driver Author Document Number System Engineering Department SFL900_LED Driver_21W_42V0.5A Date 2012 06 Revision 1.0 Key Features Both Primary-side control and secondary-side control with single stage PFC for LED driver Power factor >0.9 Built in Soft Start THD<10% using min-thd TM technique MAX 90KHz frequency clamping for EMI Pass EN55015 class B and FCC Part 15 Class B OVP /SCP protection features Low Components Count SiFirst Technology - 1 - SiFirst_RDR_SFL900_V1.0

Contents 1. Introduction... 3 2. Specifiction... 3 3. Schematic... 4 4. PCB Layout... 4 5. Module Snapshot... 6 6. Bill of Materials... 7 7. Transformer Specifications... 8 7.1 Electrical Diagram... 8 7.2 Electrical Specification... 8 7.3 Materials... 8 7.4 Transformer Build Diagram... 9 7.5 Tranformer Winding Specification... 9 8. Performance Data... 10 8.1 Test Equipments... 10 8.2 Summary of Testing Results... 10 8.3 PF/THD/Efficiency vs. Power and Line Voltage... 11 8.4 No Load Input Power... 12 8.5 Output short Input Power... 12 9. Waveforms and Testing Results... 13 9.1 Drain Voltage and Current Sense waveform @ Startup... 13 9.2 Drain Voltage and Current Sense waveform @ Nomal Operation... 13 9.3 Ripple and Noise... 15 9.4 Output current overshoot... 16 9.5 Max Mosfet Vds and second diode Vak Voltage... 16 10. Protections... 17 10.1 Output Short Circuit Protection... 17 10.2 Over Voltage Protection... 18 11. EMI Testing Results... 19 11.1 Conduction EMI Testing Results... 19 11.2 Radiation EMI Testing Results... 20 SiFirst Technology - 2 - SiFirst_RDR_SFL900_V1.0

1. Introduction This engineering report describes a 21W (42V/0.5A) universal input power supply for LED Driver applications. This reference design is based on the SiFirst s product SFL900. The mechanic dimensions are 79mm in length, 46 mm in max width. It can be using to par 38 LED lamp. SFL900 is a high performance, high power factor flyback PWM controller special for LED lighting applications. The IC adopts unique super-pfc/psr TM which can support both PSR and SSR applications. SFL900 has built-in load CC compensation and AC line CC compensation function, which can further increase LED output CC accuracy. The IC has Max.90KHz frequency clamping function and soft totem pole gate driver to improve system conduction and radiation EMI. The IC will clear External EA Feedback network before IC power on, which can reduces startup LED current spike. The IC also has soft start control during power on period. 2. Specifiction Description Min Typ Max Units Remark Input Voltage 90 115/230 264 VAC 2 Wire Frequency 47 50/60 63 Hz Output (Measure at the end of Cable) Output Current 0.5 A Output Ripple Current 150 ma Output Current A Line Regulation ±2 % Load Regulation ±3 % Continuous Output Power 21 W Efficiency(Measure at the end of Cable) Required average efficiency 88 % 115VAC/230VAC Protection Feature Short Circuit Protection Over Voltage Protection Output shut down with automatic recovery Environmental, Surge and ESD Ambient Temperature 0 40 Operating Humidity 20 90 % R.H Storage Temperature -40 60 Storage Humidity 0 95 % R.H EMI Test Pass EN55015 Class B and FCC Part15 Class B with 6dB margin SiFirst Technology - 3 - SiFirst_RDR_SFL900_V1.0

3. Schematic 4. PCB Layout Print circuit board (PCB) layout and design are very important for switching power supply where the voltage and current change with high dv/dt and di/dt. Good PCB layout minimizes excessive EMI and prevents the power supply from being disrupted during surge/esd tests. The PCB layout guidelines are highlighted as following: 1. The area enclosed by the transformer auxiliary winding, Ddd and Cdd should be kept short path. 2. The ground of the control circuits should be connected first, then to the other circuitry. 3. Regarding the ESD discharge path, put in the shortcut pad between AC line and DC output (which is the best way). The other method is to discharge the ESD energy to AC line through the primary main ground. Because ESD energy is delivered from secondary to primary through the transformer stray capacitor, the controller circuit should not be placed on the discharge path. 4. For the surge path, select fusible resistor type with wire wound type to reduce inrush current and surge energy, using π input filter (two bulk capacitor and one inductance) to share the surge energy. 5. The drain trace length should be minimized to reduce EMI. 6. RCD Clamp and output rectifier diode loop areas should be minimized to reduce EMI 7. The AC input is located away from switching nodes to minimize noise coupling that may bypass input filtering. SiFirst Technology - 4 - SiFirst_RDR_SFL900_V1.0

PCB Layout (Top view) Layout (Assembly Drawing, Bottom view) PCB SiFirst Technology - 5 - SiFirst_RDR_SFL900_V1.0

PCB Layout (Bottom Copper, Bottom view) 5. Module Snapshot SiFirst Technology - 6 - SiFirst_RDR_SFL900_V1.0

6. Bill of Materials POSITION DESCRIPTION QTY C1 Capacintor metal poly 154/630V, ±20% 1 C2 Capacintor Electrolytic 4.7UF/400V,8*12, ± 20% 1 C3 Capacintor Electrolytic 47UF/50V,6.3*11, ± 20% 1 C4 Capacintor Ceramic 102/1KV, ±20% 1 C5 C6 Capacintor Electrolytic 470UF/50V,10*20, ± 20% 2 C7 Capacintor Ceramic 101/50V, 0805, 10% 1 C8 Capacintor Ceramic 152/50V, 0805, 10% 1 C9 Capacintor Ceramic 104/50V, 0805, 10% 1 C10 Capacintor Ceramic 222/630V, 1206, 10% 1 C11 Capacintor Ceramic 10PF/50V, 0805, 10% 1 C12,C13,C14 NC CX1 Capacintor X2 0.1UF/275V P=10 1 CX2 Capacintor X2 0.047UF/275V P=10 1 LJ1 Jumper 0.6*18mm 1 R1 Resistor 10K 1206 5% 1 R3,R4 Resistor 470K 1206 5% 2 R5 Resistor 10K 0805 5% 1 R6/R7 Resistor 3.9R 1206 1% 2 R8 Resistor 3.0R 1206 1% 1 R9 Resistor 2K 1206 5% 1 R10,R18 Resistor 15K 0805 5% 2 R11,R26,R27 Resistor 100R 1206 5% 3 R12 Resistor 82R 1206 5% 1 R13,R14 Resistor 47K 1206 5% 2 R15 Resistor 100K 1206 5% 1 R16,R17 Resistor 300K 1206 5% 2 R19,R20 NC R21 Resistor 0R 1206 5% 1 R22 Resistor 91K 0805 5% 1 R23,R24 Resistor 1M 1206 5% 2 R25 Resistor 30K 1206 5% 1 D1 Diode IN4007 1A/1KV DO-41 1 D2 Diode FR107 1A/1KV DO-41 1 D3 Diode HER304 3A/300V DO-201AD 1 D4 Diode M7 1A1KV SMA 1 D5 Diode 1N4148W SOD-123 1 BR1 Bridge B6S 0.8A/600V TO269AA 1 F1 Fuse, 2A/250V 4*10 1 L1 DR6*8 400UH 0.20mm 1 L2 DR8*10 1.5mH 0.25mm 1 LF1 UU9.8 15 mh min 1 LF2 Core T10*4*5 100UH min 0.6mm 1 T1 RM8 1.5mH 1K/1V 1 Q1 MOSFET, TK5N60 5A/600V TO-220 1 CY1 Capacintor 102/400V 1 IC1 SFL900, SO-8 1 VAR1 NC PCB SFL9X0.PCB 1.6mm 1 SiFirst Technology - 7 - SiFirst_RDR_SFL900_V1.0

7. Transformer Specifications 7.1 Electrical Diagram 7.2 Electrical Specifications Primary Inductance Pin 12-10, all other windings open, measured at 1KHz, 1Vrms 1.5mH, ±8% Primary Leakage Inductance Pin 12-10, with Pins P1-P2 shorted, measured at 10KHz, 1Vrms 20uH(max) Electrical Strength 60 seconds, 60Hz, from N1,N2,N4,N5 to N3 3750Vac 7.3 Materials Item Description [1] Core: RM8, TDK PC40 or equivalent [2] Bobbin: R8, Horizontal, 12 pins (6/6). See attached drawing [3] Magnet Wire: Φ0.28mm, for the Shield Winding [4] Magnet Wire: Φ0.28mm, for the Primary Winding [5] Magnet Wire: Φ0.28mm, for the Auxiliary Winding [6] Triple Insulated Wire: Φ0.40mm, for the Secondary Winding [7] Tape: 0.05mm thick, 9mm wide [8] Tube :Φ0.70mm Teflon Tube SiFirst Technology - 8 - SiFirst_RDR_SFL900_V1.0

7.4 Transformer Build Diagram 7.5 Transformer Winding Specification No Winding Material Start Turns Finish 1 N1 0.28mm*1 2UEW 10 28 NC 2 TAPE TAPE W=9mm 2 3 N2 0.28mm*1 2UEW 12 55 11 4 TAPE TAPE W=9mm 2 5 N3 0.40mm*1 triple insulated wire P1 27 P2 6 TAPE TAPE W=9mm 2 7 N4 0.28mm*1 2UEW 11 27 10 8 TAPE TAPE W=9mm 2 9 N5 0.28mm*1 2UEW 3 12 1 10 TAPE TAPE W=9mm 3 SiFirst Technology - 9 - SiFirst_RDR_SFL900_V1.0

8. Performance Data 8.1 Test Equipments Item Vender Vender AC Source Gwinstek APS9501 Electrical Load Prodigit 3314F Digital Power Meter Voltech PM1000 Oscilloscope LeCroy Wavesufer24Xs Thermal Agilent 34970A 8.2 Summary of Testing Results Description Test Results Units Remark Input MAX Total Harmonic Distortion @90~264VAC 9.05 % <10% Output Output Current MIN MAX 0.479 0.506 A <±3% Output Ripple Current 124 ma <150mA Max. Output Voltage 47.2 V Min. Output Voltage 22.4 V Line Regulation 1.5 % <±2% Load Regulation 1.9 % <±3% Continuous Output Power 21 W Pass Average Active Mode Efficiency(Measure at the end of Cable) @115VAC 88.30 % @230VAC 89.34 % Protection Feature Short Circuit Protection OK Over Voltage Protection OK EMI EMI Test Pass EN55015 Class B and FCC Part15 Class B with 6dB margin Pass Pass SiFirst Technology - 10 - SiFirst_RDR_SFL900_V1.0

8.3 SFL900 PF/THD/Efficiency vs. Power and Line Voltage Vin (VAC) Pin (W) Vout (V) Iout (A) Pout (W) PF THD (%) Efficiency Average Efficiency load regulation 17.50 30 0.506 15.17 0.993 6.71 86.69% 90 20.45 35 0.503 17.65 0.994 6.90 86.31% 24.41 42 0.498 20.94 0.993 7.65 85.78% 86.03% ±1.3% 25.87 45 0.493 22.08 0.993 8.02 85.35% 16.82 30 0.494 14.87 0.992 7.02 88.41% 115 19.33 35 0.490 17.09 0.993 6.74 88.41% 23.04 42 0.484 20.33 0.994 6.38 88.24% 88.30% ±1.3% 24.63 45 0.481 21.71 0.995 6.58 88.14% 16.68 30 0.496 14.87 0.982 8.33 89.15% 180 19.17 35 0.490 17.14 0.987 6.18 89.41% 22.61 42 0.483 20.24 0.992 5.03 89.52% 89.40% ±1.7% 24.08 45 0.479 21.56 0.993 4.81 89.53% 17.10 30 0.502 15.19 0.960 8.48 88.83% 230 19.39 35 0.496 17.30 0.967 6.74 89.22% 22.96 42 0.487 20.58 0.976 4.82 89.63% 89.34% ±1.8% 24.25 45 0.484 21.75 0.978 4.38 89.69% 17.24 30 0.506 15.17 0.939 9.05 87.99% 264 19.74 35 0.499 17.49 0.951 7.05 88.60% 23.07 42 0.490 20.56 0.963 5.36 89.12% 88.73% ±1.9% 24.54 45 0.487 21.89 0.966 4.89 89.20% line regulation Vout=30v Vout=35v Vout=42v Vout=45v Total regulation ±1.2% ±1.3% ±1.5% ±1.4% ±2.7% SiFirst Technology - 11 - SiFirst_RDR_SFL900_V1.0

Efficiency 21W LED Driver Using SFL900 Efficiency VS Voltage 91.00% 90.00% 89.00% 88.00% 87.00% 86.00% 85.00% 84.00% 83.00% 90 115 180 230 264 Input Voltage 30V 35V 42V 45V Fig.1 Efficiency vs. Line Voltage and Output Voltage 8.4 No Load Input Power Input Voltage 90VAC 115VAC 230VAC 264VAC SFL900 182mW 213mW 311mW 371mW 8.5 Output short Input Power Input Voltage 90VAC 115VAC 230VAC 264VAC SFL900 71.3mW 123.2mW 255.8mW 315.9mW SiFirst Technology - 12 - SiFirst_RDR_SFL900_V1.0

9. Waveforms and Testing Results 9.1 Drain Voltage and Current Sense waveform @ Startup --(Red Vcomp,Blue Vout,Yellow Vcs,Green Vds) Fig.2 Startup 90VAC, 42V load Fig.3 Startup 115VAC 42V load Fig.4 Startup 230VAC, 42V load Fig.5 Startup 264VAC 42V load 9.2 Drain Voltage and Current Sense waveform @ Nomal Operation --(Red Vcomp,Blue Iout,Yellow Vcs,Green Vds) Fig.6 90VAC, 42V load Fig. 7 90VAC 42V load SiFirst Technology - 13 - SiFirst_RDR_SFL900_V1.0

Fig.8 115VAC, 42V load Fig.9 115VAC, 42V load Fig.10 230VAC, 42V load Fig.11 230VAC, 42V load Fig.12 264VAC, 42V load Fig.13 264VAC, 42V load SiFirst Technology - 14 - SiFirst_RDR_SFL900_V1.0

9.3 Ripple and Noise Input Voltage Ripple & Noise Ripple current Ripple Voltage Waveform 90VAC/60Hz 116mA 3.8V Fig.14 115VAC/60Hz 108mA 3.5V Fig.15 230VAC/50Hz 118mA 3.8V Fig.16 264VAC/50Hz 124mA 3.8V Fig.17 Note: Ripple and noise are measured at cable end with a 0.1uF/50V ceramic cap connected in parallel with a 47uF/50V aluminum electrolytic cap. The oscilloscope bandwidth is limited to 20MHz. Fig.14 Ripple & Noise @90VAC/60Hz, 42V load (Blue Iout,Red Vout) Fig.15 Ripple & Noise @ 115VAC/60Hz, 42V load (Blue Iout,Red Vout) Fig.16 Ripple & Noise @230VAC/50Hz, 42V load (Blue Iout,Red Vout) Fig.17 Ripple & Noise @ 264VAC/50Hz, 42V load (Blue Iout,Red Vout) SiFirst Technology - 15 - SiFirst_RDR_SFL900_V1.0

9.4 Output current overshoot Input Voltage Measure Data (%) SPEC Waveform 90VAC/60Hz 0 <5% Fig.18 264VAC/50Hz 0 <5% Fig.19 Fig.18 90VAC, 42V load (Blue Iout,Red Vout) Fig.19 264VAC, 42V load(blue Iout,Red Vout) 9.5 Max Mosfet Vds and second diode Vak Voltage Test Condition Max. Vds (V) Max. Vak(V) Remark Full load Startup @ 264V/50hz Normal full load @ 264V/50Hz Output Short @ 264V/50Hz 564 182 Fig.20 566 182 Fig.21 404 218 Fig.22 Fig.20 Startup 264VAC, 42V load Fig.21 Normal 264VAC 42V load SiFirst Technology - 16 - SiFirst_RDR_SFL900_V1.0

Fig.22 Output short 264VAC, 42V load Fig.23 Output short 264VAC, 42V load 10. Protections 10.1 Output Short Circuit Protection --(Red Vcomp,Blue Vcc,Yellow Vcs,Green Vds) Fig.24 output short 90VAC, 42V load Fig.25 output short 90VAC 42V load Fig.26 output short 264VAC, 42V load Fig.27 output short 264VAC 42V load SiFirst Technology - 17 - SiFirst_RDR_SFL900_V1.0

10.2 Over Voltage Protection -- Blue Vout,Yellow Vdem Input Voltage Vout (V) Vdem (V) Waveform 90VAC/60Hz 48.8 3.38 Fig.28 264VAC/50Hz 49.0 3.40 Fig.30 Fig.28 90VAC no load Fig.29 90VAC no load Fig.30 264VAC no load Fig.31 264VAC no load SiFirst Technology - 18 - SiFirst_RDR_SFL900_V1.0

11. EMI Testing Results 11.1 Conduction EMI Test EN55015 @ Full Load Report VIN=230V/50Hz, Line (Blue QP yellow--av ) VIN=230V/50Hz, Neutral (Blue QP yellow--av ) FCC 15 Class B @ Full Load Report VIN=120V/60Hz, Line (QP ) VIN=120V/60Hz, Line (AV ) SiFirst Technology - 19 - SiFirst_RDR_SFL900_V1.0

VIN=120V/60Hz, Neutral (QP ) VIN=120V/60Hz, Neutral (AV ) 11.2 Radiation EMI Test Radiation EN55022 CLASS B @ full load report VIN=230V/50Hz, Vertical VIN=230V/50Hz, Horizontal SiFirst Technology - 20 - SiFirst_RDR_SFL900_V1.0

Radiation FCC 15 CLASS B @ full load report VIN=120V/60Hz, Vertical VIN=120V/60Hz, Horizontal IMPORTANT NOTICE SiFirst Technology Nanhai, Ltd (SiFirst) reserves the right to make corrections, modifications, enhancements, improvements and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. SiFirst Technology - 21 - SiFirst_RDR_SFL900_V1.0