Integrated Buck–Boost–Quadratic Buck PFC Rectifier for Universal Input Applications

This paper presents a new single-stage single-switch (${\rm S}^{4}$ ) high power factor correction (PFC) ac/dc converter suitable for low-power applications (≪150 W) with a universal input voltage range ($90\hbox{--}265\ {\rm V}_{\rm rms}$ ). The proposed topology integrates a buck–boost input current shaper with a quadratic buck converter. As a result, the proposed converter can operate with larger duty cycles compared to the exiting ${\rm S}^{4}$ topologies; hence, making them suitable for high-frequency nonisolated applications. Additional features are gained when both the input PFC buck–boost cell and the quadratic buck cell operate in discontinuous conduction mode (DCM). 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 feasibility of the converter is confirmed with results obtained from a computer simulation and an experimental prototype.