EP-71 3.3 V, 2 A DC-DC Power Supply

19-Jul-2005

Table Of Contents

1

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

2

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

3

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

4

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

4.1

DPA-Switch Primary ............................................................................................6

4.2

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

4.3

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

5

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

6

Bill of Materials ............................................................................................................8

7

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

7.1

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

7.2

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

7.3

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

7.4

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

7.5

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

8

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

9

Performance Data .....................................................................................................13

9.1

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

9.2

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

9.2.1 Load...............................................................................................................14

9.2.2 Line ................................................................................................................14

9.3

Peak Power .......................................................................................................15

10 Waveforms ................................................................................................................15

10.1

Drain Voltage and Current, Full Load Operation ...............................................15

10.2

Output Voltage Start-Up Profile .........................................................................16

10.3

Drain Voltage and Current Start-Up Profile .......................................................16

10.4

Load Transient Response (75% to 100% Load Step) .......................................16

10.5

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

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

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

11 Thermal Performance................................................................................................20

12 Control Loop Measurements .....................................................................................22

12.1

36 VDC Maximum and Nominal Load ...............................................................22

12.2

57 VDC Maximum Load ....................................................................................23

13 Revision History ........................................................................................................24

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 isolated source to provide power to the prototype board.

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