Operation analysis of digital control based MHz totem-pole PFC with GaN device

Abstract

This paper presents an accurate analytical model to calculate the control switch on-time of voltage mode gallium nitride (GaN) devices based MHz critical conduction mode (CRM) power factor correction (PFC) rectifier. The purpose of this model is for digital control implementation of the GaN-based MHz PFC. By making the average input current equal to the sinusoidal reference current in the whole line cycle, the calculated on-time can be applied in voltage-mode-based CRM PFC, to achieve low input current distortion and high power factor. The model considers the resonance between inductor and switch parasitic capacitor, which improves its accuracy at MHz switching frequency range. In addition, this model is applicable when zero-voltage-switching (ZVS) extension is applied.