DER-19

TOP245P Multiple Output Set Top Box

March 30, 2004

Page 4 of 25

Power Integrations, Inc.

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

www.powerint.com

1

Introduction

This engineering report describes a multiple output evaluation board designed using

TOP245P. The specification chosen is targeted towards new Set Top Box systems that

incorporate a hard disk. These systems require a peak power capability when the hard

disk is first spun-up.

Peak power operation requires magnetics and diodes specified to handle the currents at

the specified peak power point. If peak power operation is not required, designing the

supply for maximum continuous power will save additional cost.

The document contains the power supply specification, schematic, bill of materials,

transformer documentation, printed circuit layout, and measured performance data from

the prototype unit shown in Figure 1.

Figure 1 – Populated Circuit Board (Scale in cm)