DER-99

Set Top Box 17.4 W Power Supply

September 12, 2005

Page 2 of 29

Power Integrations

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Table Of Contents

1

Introduction................................................................................................................. 4

2

Power Supply Specification ........................................................................................ 5

3

Schematic................................................................................................................... 6

4

Circuit Description ...................................................................................................... 8

4.1

EMI Filtering ........................................................................................................ 8

4.2

TOPSwitch Primary ............................................................................................. 8

4.3

Power Good signal .............................................................................................. 8

5

PCB Layout ................................................................................................................ 9

6

Bill Of Materials ........................................................................................................ 10

7

Transformer Specification......................................................................................... 12

7.1

Electrical Diagram ............................................................................................. 12

7.2

Electrical Specifications..................................................................................... 12

7.3

Materials............................................................................................................ 12

7.4

Transformer Build Diagram ............................................................................... 13

7.5

Transformer Construction.................................................................................. 14

8

Transformer Spreadsheets....................................................................................... 15

9

Performance Data .................................................................................................... 18

9.1

Efficiency........................................................................................................... 18

9.2

Regulation ......................................................................................................... 18

9.2.1

Cross Regulation........................................................................................ 18

9.3

Thermal Performance........................................................................................ 18

9.4

Surge test.......................................................................................................... 19

9.4.1

Surge Test Setup ....................................................................................... 19

9.4.2

Surge Test Results..................................................................................... 19

9.5

AC Line Over Voltage (388 VAC swell) ............................................................. 20

9.6

Hold-Up Time and Power Good ........................................................................ 21

10

Waveforms............................................................................................................ 23

10.1

Drain Voltage and Current, Normal Operation .................................................. 23

10.2

Drain Voltage and Current Start-up Profile........................................................ 23

10.3

Output Ripple Measurements............................................................................ 24

10.3.1

Ripple Measurement Technique ................................................................ 24

10.3.2

Measurement Results ................................................................................ 25

11

Control Loop Measurements................................................................................. 26

11.1

160 VAC Maximum Load .................................................................................. 26

11.2

230 VAC Maximum Load .................................................................................. 26

12

Conducted EMI ..................................................................................................... 27

13

Revision History .................................................................................................... 28