LED Driver Design with iW3620 Summary and Features : 1. LED driver, 40V, 350mA ; Wide AC input...

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

2iWatt Confidential – Do Not Copy 40V/350mA LED Driver 17 Jun 2009 Page:

1. Specification

Description Symbol Min Typ Max Units Comment

Input

Voltage VIN 90 264 VAC 2 Wire

Frequency fLINE 47 50 63 Hz

Open-load Input Power (264VAC)

W

Output

Const Voltage

Output Voltage VOUT_CV 40 V Measured at the PCB connector

Output Current IOUT_CV A

Const Current

Output Voltage VOUT_CV V Min Vout is depend on Vcc

Output Current IOUT_CV 0.35 A

Total Output Power

Continuous Output Power POUT 14 W

Over Current Protection IOUT_MAX A Auto-restart

Efficiency 83 % Measured at end of PCB

Power Fact PF 0.9 Harmonic meet IEC61000-3-2

Turn on Delay Time Sec

Conducted EMI Meets EN55015B

Hi-pot test 3 KV

Operation temperature Topr Free convection, sea level40 °C


2. Schematic


3.Circuit Board Photograph

Top side


core

7(F)

SECPRI

2UEW 0.21mm*1*17T – Primary (Clockwise)

6(S)

MATERIALS:1. Core : EC28(Ferrite Material TDK PC40 or equivalent)2. Bobbin :EC28. Primary=5, Secondary=53. 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) = 0.9mH @10KHz2. Primary Leakage Inductance (Lk)< = 30uH @10KHz3. Electrical Strength = 3KV, 50/60Hz,1Min

FINISHED :1. Cut remained of Pin after wires termination2. Core is connected to PRI-GND pin7.3. Varnish the complete assembly

4

56

7

Primary

Bias/sense

2UEW 0.17mm*2*10T Bias (clockwise)

4. Transformer Design

A(S)

5(S)

Cuffing Tape 40(L)x15(W)mmSmall solder Joint with fine wire

Finished Assembly

Fold up both side of Tape

Cut Copper Foil (4x20x0.05)mm


Triple Insulated wire 0.28mm*1*8T Secondary

7(S) Copper foil 4(W)*20(L)mm shielding

32T

A

B

Secondary

4(F)



X(S)



B(F)

X(F)


5. Differential Mode Inductor L1

Ferrite core size : AxB 8x10mm

Wire gauge: 0.26mm, 150 Turns

Inductance @10kHz, 1V: 7500uH +/-20%

ICR: 0.8 OHM +/-20%

Differential Mode Inductor L2

Ferrite core size : AxB 8x10mm

Wire gauge: 0.3mm, 120 Turns

Inductance @10kHz, 1V: 450H +/-20%

ICR: 0.5 OHM +/-20%


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) = 900uH @10KHz 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


7. Bill of MaterialItem Qty. Ref. Description U/ P (RMB)

1 1 F1 1.25A/250Vac Fuse

2 1 CX1 0.1uF/250V X Capacitor

3 2 C2,C3 MPE 0.1uF,400V

4 1 C4 22uF/400V,E-CAP,1050C

5 1 C5 2.2nF,1KV

6 1 C6,C8 470pF,50V,NPO,SMD-0603

7 1 C7 68pF,50V,NPO,SMD-0603

8 1 C9 1nF,50V,NPO,SMD-0603

9 1 C11 220uF,50V,E-CAP,1050C

13 1 L1 750uH(8*10)

14 2 L2 470uH(8*10)

15 1 L3 EFD15 Transformer

16 1 L4 UU8.5

18 1 DBR1 DBR107

19 1 D1,D2,D3 HER107

20 2 D4 FR107

21 1 D5,D6 1N4148,SMD

23 2 D7 HER207

24 1 U1 IW3620,Off-line digital PWM controller,SOT-8

25 1 Q1 4N60,SMD

26 1 T1 EC28

27 3 R1 4.7KΩ +/-5%,SMD-0805

28 1 R2 4.7KΩ +/-5%,SMD-1206

29 2 R3,R4 560KΩ +/-5%,SMD-1206

30 1 R5 100KΩ +/-5%,SMD-1206

35 1 R6 47Ω +/-5%,SMD-0603

31 1 R7 22KΩ +/-5%,SMD-0603

32 1 R8,R9 1.8Ω +/-5%,SMD-0805

33 3 R10 1KΩ +/-1%,SMD-0603

34 1 R11 20KΩ +/-5%,SMD-0603

35 1 R12 10Ω +/-5%,SMD-0805

36 1 R13 22KΩ +/-5%,SMD-0603

37 1 R14 3KΩ +/-1%,SMD-0603

38 1 R15 22KΩ +/-1%,SMD-0805


VIN=264VAC, TAMB=25VIN=90VAC, TAMB=25

* Note: Output voltage measured at PCB end, TAMB=25

V- I Curve

20

22

24

26

28

30

32

34

36

38

40

42

0 100 200 300 400

I out

Vout

8. V-I Curve

V- I Curve

202224262830323436384042

0 100 200 300 400

I out

Vout


9. Efficiency Measurement

* Note: Output voltage measured at end of PCB.

0

10

20

30

40

50

60

70

80

90

80 100 120 140 160 180 200 220 240 260 280

Vin(Vac)

Eff

(%)


10. VDS waveform

Test Condition:

VIN=264VAC, VOUT_CV=40V

Result:

VDS_MAX=504V

Remark: Mosfet Spec__4A 600V


11. Start up and turn on delay time

110VAC,Full Load

TST_DELAY=1.83S

264VAC,Full Load

TST_DELAY=716mS


12. PF and harmonic current

Vin__110V PF=0.928 3rd <28% 5th_<13%

Vin__230V PF=0.933 3rd <27% 5th_<9%

___IEC61000-3-2 requirement---- 3rd <86% 5th_<61%


13.Conducted EMI ( Input 115Vac Full Load, output floating )

Peak scan N

Peak scan L

Peak ScanQP Limit line



14. Conducted EMI ( Input 230Vac Full Load, output floating )

Peak scan N

Peak scan L



LED Driver Design with iW3620 Summary and Features : 1. LED driver, 40V, 350mA ; Wide AC input...

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