Single-stage single-switch PFC converter for wide-input extreme step-down voltage applications

Abstract

SUMMARY This paper presents a new single-stage single-switch high power factor correction AC/DC converter suitable for low-power applications (< 150 W) with a universal input voltage range (90–265 Vrms). The proposed topology integrates a buck–boost input current shaper followed by a buck and a buck–boost converter, respectively. As a result, the proposed converter can operate with larger duty cycles compared with the existing single-stage single-switch topologies, hence, making them suitable for extreme step-down voltage conversion applications. Several desirable features are gained when the three integrated converter cells operate in discontinuous conduction mode. These features include low semiconductor voltage stress, zero-current switch at turn-on, and simple control with a fast well-regulated output voltage. A detailed circuit analysis is performed to derive the design equations. The theoretical analysis and effectiveness of the proposed approach are confirmed by experimental results obtained from a 100-W/24-Vdc laboratory prototype. Copyright © 2011 John Wiley & Sons, Ltd.