BOOST CONVERTER FOR POWER FACTOR CORRECTION

摘要

A zero voltage switching boost converter for power factor correction. The boost converter comprises a boost inductor (101), a switching transistor (103) and a control circuitry (120) arranged to control the switching transistor based on a demagnetization signal proportional to a current in the boost inductor (101). There is a signal alteration circuitry (160) arranged to add a high frequency, small amplitude signal to said demagnetization signal, thereby forming an altered demagnetization signal. As a result, multiple valley switching is accomplished and high frequency content is reduced, which makes it possible to comply with EMC requirements at lower cost.