Boost-Type Single-Stage Step-Down Resonant Power Factor Correction Converter

Conventional boost power factor correction (PFC) converter is only suitable for two-stage power conversion system due to its high output voltage. Inherent step-up characteristic limits its applications in single-stage low voltage output. In this article, a boost-type single-stage step-down resonant PFC converter, which combines a boost PFC converter and a resonant switched capacitor network by using one active switch, is proposed and analyzed. Similar to conventional boost PFC converter, the proposed converter can achieve unity power factor and low input current ripple in universal-input applications. Moreover, the proposed converter can achieve step-down voltage conversion. Furthermore, high-efficiency is realized due to single-stage power conversion. The proposed converter is studied in terms of operation principle, voltage gain, power factor analysis, and key circuit parameters design. Finally, a 70-W prototype with 96.05% peak efficiency is built to verify the theoretical analysis results.