EP68 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 Spreadsheet .........................................................................................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) .......................................17

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 telecom isolation requirements, this

engineering prototype has not been agency approved.

Page 2 of 28

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