Power Integrations, Inc.

5245 Hellyer Avenue, San Jose, CA 95138 USA.

Tel: +1 408 414 9200 Fax: +1 408 414 9201

www.powerint.com

Design Example Report

Title

32W (47W peak) Multiple Output supply

using TOP245P

Specification

Input: 195 - 265 VAC

Output: 3.3V/3A, 5V/2A (2.5A Peak),

12V/0.5A (1.5A Peak), 20V/0.3A

Application

Set Top Box

Author

Power Integrations Applications Department

Document

Number

DER-19

Date

March 30, 2004

Revision

1.0

Summary and Features

This report describes a design for a multiple output power supply, such as required for

a Set Top Box, featuring the following:

• Very high full power efficiency (> 83% at full power)

• 32W Continuous power rating

• <0.5W no-load consumption

• Efficiency >75% at 10% output power

• Small DIL08 package for TOP245P requiring no external heatsink

• 50W peak power capability allows for high peak output power demands (e.g.

for hard disk spin-up)

• Low EMI (Meets EN55022 with output ground connected to Earth)

The products and applications illustrated herein (including circuits external to the products and transformer

construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign

patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found