July 2008

Rev 1

1/24

AN2755

Application note

400 W FOT-controlled PFC pre-regulator with the L6562A

Introduction

This application note describes an demonstration board based on the transition-mode PFC

controller L6562A and presents the results of its bench demonstration. The board

implements a 400 W, wide-range mains input PFC pre-conditioner suitable for ATX PSU, flat

screen displays, etc. In order to allow the use of a low-cost device like the L6562A at this

power level, usually prohibitive for this device, the chip is operated with fixed-off-time control.

This allows continuous conduction mode operation, normally achievable with more

expensive control chips and more complex control architectures.

Figure 1.

Demonstration board (EVL6562A-400W)

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