LED Driver Design with iW3620 Summary and Features : 1. LED driver, 40V, 350mA ; Wide AC input range: 90Vac-264Vac 2.For Isolated Applications 3.High Efficiency, High Power Factor and Least Parts Solution 4.Meet EMI Requirement (EN55015BQP&AV scan) 5.Fully Protection Against AC input UV/OV,O/P Short &Open, Component single fault

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 2 1. Specification DescriptionSymbolMinTypMaxUnitsComment Input VoltageV IN 90264V AC 2 Wire Frequencyf LINE Hz Open-load Input Power (264V AC ) W Output Const Voltage Output VoltageV OUT_CV 40V Measured at the PCB connector Output CurrentI OUT_CV A Const Current Output VoltageV OUT_CV V Min Vout is depend on Vcc Output CurrentI OUT_CV 0.35A Total Output Power Continuous Output PowerP OUT 14W Over Current ProtectionI OUT_MAX A Auto-restart Efficiency  83% Measured at end of PCB Power FactPF0.9 Harmonic meet IEC Turn on Delay TimeSec Conducted EMIMeets EN55015B Hi-pot test3KV Operation temperatureT opr Free convection, sea level 40°C

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 3 2. Schematic

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 4 3.Circuit Board Photograph Top side

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 5 core 7(F)7(F) SECPRI 2UEW 0.21mm*1*17T – Primary (Clockwise) 6(S)6(S) MATERIALS: 1.Core : EC28(Ferrite Material TDK PC40 or equivalent) 2.Bobbin :EC28. Primary=5, Secondary=5 3.Magnet Wires (Pri) : Type 2-UEW 4.Magnet Wire (Sec) : Triple Insulated Wires 5.Layer Insulation Tape :3M1298 or equivalent. SCHEMATIC 51T 10T ELECTRICAL SPECIFICATIONS: 1.Primary Inductance (Lp) = 2.Primary Leakage Inductance (Lk)< = 3.Electrical Strength = 3KV, 50/60Hz,1Min FINISHED : 1.Cut remained of Pin after wires termination 2.Core is connected to PRI-GND pin7. 3.Varnish the complete assembly Primary Bias/sense 2UEW 0.17mm*2*10T Bias (clockwise) 4. Transformer Design A(S) 5(S) Cuffing Tape {40(L)x15(W)}mm Small solder Joint with fine wire Finished Assembly Fold up both side of Tape Cut Copper Foil (4x20x0.05)mm 2UEW 0.21mm*1*17T – Primary (Clockwise) Triple Insulated wire 0.28mm*1*8T Secondary 7(S) Copper foil 4(W)*20(L)mm shielding 32T A B Secondary 4(F)4(F) Triple Insulated wire 0.28mm*1*8T Secondary 2UEW 0.21mm*1*17T – Primary (Clockwise) X(S) Triple Insulated wire 0.28mm*1*8T Secondary Triple Insulated wire 0.28mm*1*8T Secondary B(F) X(F)

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 6 5. Differential Mode Inductor L1 Ferrite core size : AxB 8x10mm Wire gauge: 0.26mm, 150 Turns 1V: 7500uH +/- 20% ICR: 0.8 OHM +/-20% Differential Mode Inductor L2 Ferrite core size : AxB 8x10mm Wire gauge: 0.3mm, 120 Turns 1V: 450H +/-20% ICR: 0.5 OHM +/-20%

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 7 6.Common Choke L1 for EMI core : UU8.5 (Ferrite Material TDK PC40 or equivalent) Bobbin : UU8.5 Turns:100T Inductance 6.6mH +/-20% SCHEMATIC 0.26*1*155 Ts ELECTRICAL SPECIFICATIONS: 1.Inductance (Lp) = 2.Core : EFD15 (Ferrite Material TDK PC40 or equivalent) 3.Bobbin : EFD15 Vertical 4.Ferrite core is connected to Pin 10 after assembling 5.Cut remained of Pin1,2,3,4,7,8,9 after wires termination 6.Varnish the complete assembly 7 3 PFC Inductor L4 Design 4

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 8 7. Bill of Material

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: 9 V IN =264V AC, T AMB =25 ℃ V IN =90V AC, T AMB =25 ℃ * Note: Output voltage measured at PCB end, T AMB =25 ℃ 8. V-I Curve

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: Efficiency Measurement * Note: Output voltage measured at end of PCB.

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: V DS waveform Test Condition: V IN =264VAC, V OUT_CV =40V Result: V DS_MAX =504V Remark: Mosfet Spec__4A 600V

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: Start up and turn on delay time 110V AC,Full Load T ST_DELAY =1.83S 264V AC,Full Load T ST_DELAY =716mS

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: PF and harmonic current Vin__110V PF= rd <28% 5th_<13% Vin__230V PF= rd <27% 5th_<9% ___IEC requirement---- 3rd <86% 5th_<61%

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: Conducted EMI ( Input 115Vac Full Load, output floating ) Peak scan N Peak scan L Peak Scan QP Limit line Peak Scan QP Limit line

iWatt Confidential – Do Not Copy 40V/350mA LED Driver17 Jun 2009 Page: Conducted EMI ( Input 230Vac Full Load, output floating ) Peak scan N Peak scan L Peak Scan QP Limit line Peak Scan QP Limit line