DER-94

LCD Monitor Internal Supply

September 12, 2005

Page 2 of 34

Power Integrations

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Table Of Contents

1

Introduction................................................................................................................. 4

2

Power Supply Specification ........................................................................................ 5

3

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

4

Circuit Description ...................................................................................................... 8

4.1

Input EMI Filtering ............................................................................................... 8

4.2

TOPSwitch Primary ............................................................................................. 8

4.3

Output Rectification ............................................................................................. 8

4.4

Output Feedback................................................................................................. 8

4.5

Active Preload/Output Protection ........................................................................ 9

5

Printed Circuit Layout ............................................................................................... 10

6

Bill Of Materials ........................................................................................................ 11

7

Transformer Specification......................................................................................... 13

7.1

Electrical Diagram ............................................................................................. 13

7.2

Electrical Specifications..................................................................................... 13

7.3

Materials............................................................................................................ 14

7.4

Transformer Build Diagram ............................................................................... 14

7.5

Transformer Construction.................................................................................. 15

7.6

Transformer Spreadsheet ................................................................................. 17

8

Performance Data .................................................................................................... 20

8.1

Efficiency........................................................................................................... 20

8.2

Standby Input Power ......................................................................................... 20

8.3

Cross Regulation Matrix .................................................................................... 21

8.4

Load Regulation Matrix, 90VAC ........................................................................ 21

8.5

5V Power Limit .................................................................................................. 21

9

Thermal Performance............................................................................................... 22

10

Waveforms............................................................................................................ 23

10.1

Drain Voltage and Current, Normal Operation .................................................. 23

10.2

Output Voltage Start-up Profile ......................................................................... 23

10.3

Load Transient Response (75% to 100% Load Step) ....................................... 24

10.4

Overvoltage Protection...................................................................................... 24

11

Output Ripple........................................................................................................ 25

11.1

Ripple Measurement Technique ....................................................................... 25

11.2

Measurement Results ....................................................................................... 26

11.3

Ripple with 12 V Burst Load .............................................................................. 27

12

Gain-Phase Measurements .................................................................................. 28

12.1

115 VAC Maximum Load .................................................................................. 28

12.2

230 VAC Maximum Load .................................................................................. 29

13

Line Transient Testing .......................................................................................... 30

14

Conducted EMI......................................................................................................... 31

15

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