A Microcontroller-Based High Efficiency Critical Conduction Mode Control for GaN-Based Totem-Pole PFC

This paper introduces a new control method for Gallium-Nitride (GaN) device based critical conduction mode (CRM) totem-pole power factor correction (PFC) rectifiers. A simple digital control method based on synchronous rectifier (SR) on-time calculation is proposed such that the converter operates in CRM, achieves zero voltage switching (ZVS), realizes high efficiency, and also avoids the delay and noise issues from zero-current detection (ZCD) circuit. Average current mode control is implemented to achieve unity power factor (PF) and low total harmonic distortion (THD). The proposed control method is implemented in a microcontroller unit (MCU) and demonstrated on a two-phase interleaved 2.2kW GaN-based totem-pole PFC prototype.