Development of a Mixed-Signal PFC Control IC with Fast Dynamic Response

Abstract

This paper presents a mixed-signal power-factor-correction (PFC) control IC for the single-phase critical-conduction-mode (CRM) boost AC/DC converters. The peak current mode control is used and realized by using the analog circuit technique. The outer voltage loop control adopts digital control technique to implement. This paper analyzes effect of the hysteresis band of the comparator in current loop is implemented by analog circuit. In digital voltage loop, this paper proposes usage of a digital notch filter to achieve fast dynamic response under large step load variations while maintaining a low total-harmonic-distortion (THD) and a high power factor (PF). The proposed mixed-signal PFC control scheme has been verified by using computer simulation via PSIM and Simplis to validate feasibility.