March 2014

DocID024230 Rev 1

1/15

AN4250

Application note

Fishbone diagram for power factor correction

Rosario Costanzo, Gianluca Messina, Antonino Gaito

Introduction

This report aims to show through a Fishbone diagram, all possible causes of failure of the

Power MOSFET mounted on a PFC.

This work is divided into 5 sections:

• The first one describes the power factor

• The second describes the Boost converter

• The third describes the PFC system

• The forth paragraph shows all critical conditions causing the failure of the Power MOSFET

and builds up the Fishbone diagram

• Last paragraph presents a specific Fishbone parallel configuration

www.st.com