DER-97

21.7 W PoE Adapter

September 12, 2005

Page 2 of 31

Power Integrations

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Table Of Contents

1

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

2

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

3

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

4

Circuit Operation ........................................................................................................ 6

4.1

General ............................................................................................................... 6

4.2

Description .......................................................................................................... 6

5

Bill of Materials ........................................................................................................... 7

6

Layout......................................................................................................................... 9

7

Transformer Design Spreadsheet ............................................................................ 10

8

Transformer Specification......................................................................................... 13

9

Performance............................................................................................................. 17

9.1

Efficiency........................................................................................................... 17

9.2

Regulation vs. Load........................................................................................... 18

9.3

Regulation vs. Line............................................................................................ 19

9.4

Raw Performance Data ..................................................................................... 20

10

Waveforms............................................................................................................ 21

10.1

Drain Current and Voltage................................................................................. 21

10.2

Output Transient Load Response ..................................................................... 22

10.3

Output Ripple Voltage ....................................................................................... 23

10.4

Switching Ripple................................................................................................ 23

10.5

Line Frequency Ripple ...................................................................................... 24

10.6

Output Voltage Shutdown Profile ...................................................................... 26

11

Thermal Test......................................................................................................... 27

11.1

Thermal Performance........................................................................................ 27

12

Conducted EMI ..................................................................................................... 29

12.1

Conducted EMI Performance ............................................................................ 29

13

Revision History .................................................................................................... 30

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.