DER-46

6 W peak, Multiple output PSU for DVB-T

April 20, 2005

Page 2 of 22

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Table Of Contents

1

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

2

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

3

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

4

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

4.1

TinySwitch Primary ............................................................................................. 6

4.2

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

4.3

Output Feedback and control.............................................................................. 6

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 ........................................................................................................... 10

7.4

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

7.5

Winding Instructions.......................................................................................... 11

8

Transformer Spreadsheet ........................................................................................ 12

9

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

9.1

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

9.2

Worst Case Cross Regulation........................................................................... 14

10

Thermal Performance........................................................................................... 15

11

Waveforms ........................................................................................................... 15

11.1

Drain Voltage and Current, Normal Operation .................................................. 15

11.2

Output Ripple Measurements ........................................................................... 16

11.2.1

Ripple Measurement Technique ................................................................ 16

11.2.2

Measurement Results................................................................................ 17

11.3

Transient Response: 3.3V – 50% - 100% Load Step........................................ 19

12

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

13

Revision History ................................................................................................... 21

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.

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.