EP-73 5.7 V, 400 mA Charger / Adapter

25-Oct-2004

Table Of Contents

1

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

2

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

3

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

4

Circuit Description ......................................................................................................7

4.1

Input EMI Filtering ...............................................................................................7

4.2

LinkSwitch-HF

Primary........................................................................................7

4.3

Output Rectification .............................................................................................7

4.4

Output Feedback.................................................................................................7

4.5

Design Aspects for EMI .......................................................................................8

5

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

6

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

7

Transformer Specification.........................................................................................11

7.1

Electrical Diagram .............................................................................................11

7.2

Electrical Specifications.....................................................................................11

7.3

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

7.4

Transformer Build Diagram ...............................................................................12

7.5

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

8

Transformer Design Spreadsheet.............................................................................13

9

Performance Data ....................................................................................................16

9.1

Efficiency ...........................................................................................................16

9.2

No-load Input Power..........................................................................................17

9.3

Regulation .........................................................................................................17

9.3.1

CV and CC Output Characteristics.............................................................17

9.3.2

Load Regulation in CV ...............................................................................18

10

Thermal Performance ...........................................................................................19

11

Line Surge.............................................................................................................20

12

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

12.1 Drain Voltage and Current, Normal Operation...................................................21

12.2 Output Voltage Start-up Profile..........................................................................22

12.3 Drain Voltage and Current Start-up Profile ........................................................22

12.4 Load Transient Response (75% to 100% Load Step) .......................................23

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

12.5.1

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

12.5.2

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

13

Conducted EMI .....................................................................................................26

13.1 115 VAC Input, Full Load ..................................................................................26

13.2 230 VAC Input, Full Load ..................................................................................27

14

Appendix A............................................................................................................28

15

Revision History ....................................................................................................33

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.

Page 2 of 36

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