DER-75

2.4W Power Supply using LNK520P

September 12, 2005

Page 2 of 23

CONFIDENTIAL

Power Integrations

Tel: +1 408 414 9200 Fax: +1 408 414 9201

www.powerint.com

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

LinkSwitch Primary.............................................................................................. 6

4.3

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

4.4

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

4.5

No Load Consumption......................................................................................... 6

5

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

6

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

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

6.1

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

6.2

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

6.3

Materials.............................................................................................................. 9

6.4

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

6.5

Transformer Construction.................................................................................. 10

7

Transformer Spreadsheets....................................................................................... 11

8

Performance............................................................................................................. 13

8.1

Efficiency........................................................................................................... 13

8.2

No-Load Input Power ........................................................................................ 13

8.3

Regulation ......................................................................................................... 14

8.4

Measurement Data............................................................................................ 15

9

Waveforms ............................................................................................................... 16

9.1

Drain Voltage and Current, Normal Operation .................................................. 16

9.2

Load Transient Response (75% to 100% Load Step) ....................................... 17

9.3

Output Ripple Measurements............................................................................ 18

9.3.1

Ripple Measurement Technique ................................................................ 18

9.3.2

Measurement Results ................................................................................ 19

10

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

11

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.