DER-33

3.9W CC/CV TNY266P Charger

April 1, 2004

Page 2 of 24

Power Integrations

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Table Of Contents

1

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

2

Photograph .................................................................................................................3

3

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

4

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

5

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

5.1

Input Rectification, Bulk Capacitance and EMI Filtering ......................................6

5.2

Primary DRAIN Voltage Clamp Circuit ................................................................6

5.3

Auxiliary Bias Supply ...........................................................................................6

5.4

Output Rectification and Filtering.........................................................................6

5.5

Output Voltage Sensing and Feedback ...............................................................7

6

PCB Layout ................................................................................................................8

7

Bill Of Materials...........................................................................................................9

8

Transformer Specification.........................................................................................10

8.1

Electrical Diagram .............................................................................................10

8.2

Electrical Specifications.....................................................................................10

8.3

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

8.4

Transformer Build Diagram ...............................................................................11

8.5

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

9

Transformer Spreadsheets .......................................................................................13

10

Performance Data .................................................................................................15

10.1

Output Characteristic.........................................................................................15

10.2

Efficiency ...........................................................................................................15

10.3

No-load Input Power..........................................................................................16

10.4

Load and Line Regulation in CV mode ..............................................................16

11

Thermal Performance ...........................................................................................17

12

Waveforms............................................................................................................18

12.1

Drain Voltage Normal Operation........................................................................18

12.2

Output Voltage Start-up Profile..........................................................................18

12.3

Drain Voltage Start-up Profile ............................................................................19

12.4

Output Ripple Measurements ............................................................................20

12.4.1

Ripple Measurement Technique.................................................................20

12.4.2

Measurement Results ................................................................................21

13

Conducted EMI .....................................................................................................22

14

Revision History ....................................................................................................23

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.