DER-36

42W, 4 Output Set Top Box Supply

April 27, 2004

Page 2 of 23

Power Integrations

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Table Of Contents

1

Introduction................................................................................................................. 3

2

Power Supply Specification ........................................................................................ 4

3

Schematic................................................................................................................... 5

4

Circuit Description ...................................................................................................... 6

4.1

Input EMI Filtering ............................................................................................... 6

4.2

TOPSwitch Primary ............................................................................................. 6

4.3

Output Rectification ............................................................................................. 6

4.4

Output Feedback................................................................................................. 6

5

PCB Layout ................................................................................................................ 7

6

Bill Of Materials .......................................................................................................... 8

7

Transformer Specification......................................................................................... 10

7.1

Electrical Diagram ............................................................................................. 10

7.2

Electrical Specifications..................................................................................... 10

7.3

Materials............................................................................................................ 11

7.4

Transformer Build Diagram ............................................................................... 11

7.5

Transformer Construction.................................................................................. 12

8

Transformer Spreadsheets....................................................................................... 13

9

Performance Data .................................................................................................... 17

9.1

Thermal Performance........................................................................................ 17

10

Waveforms............................................................................................................ 18

10.1

12V Output Turn Off .......................................................................................... 18

10.2

5V Transient Response..................................................................................... 19

11

Conducted EMI ..................................................................................................... 20

12

Revision History .................................................................................................... 22

Important Note:

Although this board is designed to satisfy safety isolation requirements, the engineering

prototype has not been agency approved. Therefore, all testing should be performed

using an isolation transformer to provide the AC input to the prototype board.

Design Reports contain a power supply design specification, schematic, bill of materials,

and transformer documentation. Performance data and typical operation characteristics

are included. Typically only a single prototype has been built.