Analysis and Design of a Charge-Pump-Based Resonant AC-DC Converter with Inherent PFC Capability

This paper presents the analysis and design of a resonant power factor correction (PFC) rectifier for the first stage in single-phase front-end offline converters targeting low-power applications (up to 100 W). With the addition of a charge pump circuit comprised of a capacitor and a diode to a class-DE resonant converter, PFC functionality is achieved inherently. The operation is based on soft switching, allowing for increased switching frequencies with reduced switching losses. A 1 MHz prototype employing wide-bandgap (WBG) switching devices is built and tested to validate the analysis and proposed design method. The prototype achieves up to 50 W of output power with a power factor of 0.99, a total harmonic distortion (THD) of 8.6 %, and an efficiency of up to 88 %; with harmonic magnitudes well-within the IEC 61000-3-2 standard class-C device limits, making it suitable for use as the rectifier stage in LED drivers. Despite the additional circuit stresses from the charge pump operation, the proposed converter offers simplicity and low component overhead, with the potential for higher frequency operation towards higher power densities.