DER-111

3.15 W General Purpose Adapter

October 26, 2005

Page 2 of 23

Power Integrations

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Table Of Contents

1

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

2

Photograph................................................................................................................. 3

3

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

4

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

5

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

5.1

Input Rectification, Bulk Capacitance and EMI Filtering ...................................... 6

5.2

Primary DRAIN Voltage Clamp Circuit ................................................................ 6

5.3

Auxiliary Bias Supply........................................................................................... 6

5.4

Output Rectification and Filtering ........................................................................ 6

5.5

Output Voltage Sensing and Feedback............................................................... 6

6

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

7

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

8

Transformer Specification........................................................................................... 9

8.1

Electrical Diagram ............................................................................................... 9

8.2

Electrical Specifications....................................................................................... 9

8.3

Materials............................................................................................................ 10

8.4

Transformer Build Diagram ............................................................................... 10

8.5

Transformer Construction.................................................................................. 11

9

Transformer Spreadsheets....................................................................................... 12

10

Performance Data................................................................................................. 14

10.1

Efficiency........................................................................................................... 14

10.2

No-load Input Power.......................................................................................... 14

10.3

Load and Line Regulation ................................................................................. 15

11

Thermal Performance ........................................................................................... 16

12

Waveforms............................................................................................................ 17

12.1

Drain Voltage Normal Operation ....................................................................... 17

12.2

Output Voltage Start-up Profile ......................................................................... 17

12.3

Drain Voltage Start-up Profile............................................................................ 18

12.4

Output Ripple Measurements............................................................................ 19

12.4.1

Ripple Measurement Technique ................................................................ 19

12.4.2

Measurement Results ................................................................................ 20

13

Conducted EMI ..................................................................................................... 21

14

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

Important Notes:

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 isolated source to provide power 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.