MC33362

http://onsemi.com

11

Figure 22. 20 W Off−Line Converter

Osc

PWM

PWM Latch

Thermal

EA

Startup

Reg

UVLO

14.5 V/

9.5 V

OVP

2.6 V

2.6 V

R1

8

6

7

4, 5, 12, 13

11

16

9

10

1

92 to 138

5.05 V/4.0 A

R

S

Q

Driver

3

LEB

Mirror

270

µA

8.2 k

Vac Input

C3

1.5 nF

C4

1.0

R2

2.7 k

IC1 MC33362

5

4

R4

16 k

R3

2.7 k

C2

10

C1

47

C6

47 pF

C5

4.0 nF

R6

100 k

1.0 W

DC Output

C12

1.0

C11

220

R8

220

R9

2.80 k

C7

100 nF

1

2

3

1

2

R10

2.74 k

IC3

TL431B

C8

330

C9

330

C10

330

T1

D6

MUR

120

R5

39

D5

MUR

160

L1

5.0

µH

R7

2.2 k

1.0 W

IC2

MOC

8103

1N4004

D3

D4

D2

D1

F1

1.0 A

ILimit

D7

MBR

2515L

Table 1. Converter Test Data

Test

Conditions

Results

Line Regulation

D = 1.0 mV

Load Regulation

D = 9.0 mV

Output Ripple

Triangular = 10 mVpp

Spike = 60 mVpp

Efficiency

78.4%

This data was taken with the components listed below mounted on the printed circuit board shown in

Figure 23.

For high efficiency and small circuit board size, the Sanyo Os−Con capacitors are recommended for C8,

C9, C10 and C11.

C8, C9, C10 = Sanyo Os−Con #6SA330M, 330 mF 6.3 V.

C11 = Sanyo Os−Con #10SA220M, 220 mF 10 V.

D7 = MBR2515L mounted on Aavid #592502B03400 heatsink.

L1 = Coilcraft S5088−A, 5.0 mH, 0.11 W.

T1 = Coilcraft S5069−A

Primary: 58 turns of # 26 AWG, Pin 1 = start, Pin 8 = finish.

Two layers 0.002″ Mylar tape.

Secondary: 4 turns of # 18 AWG, 2 strands bifiliar wound, Pin 5 = start, Pin 4 = finish.

Two layers 0.002″ Mylar tape.

Auxiliary: 10 turns of # 26 AWG wound in center of bobbin, Pin 2 = start, Pin 7 = finish.

Two layers 0.002″ Mylar tape.

Core and Bobbin: Coilcraft PT1950, E187, 3F3 material.