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

This article 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 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 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 light-emitting diode (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 toward higher power densities.