Load Adaptive Control for Mixed-Signal PFC Control IC

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 applied and analyzed by using the analog circuit. The voltage control loop is implemented in digital approach. This paper analyzes effect of the hysteresis band effect of the analog current comparator in current loop. In digital voltage loop, the proper quantization resolutions both ADC and DAC are determined. The digital voltage controller uses a digital notch filter to achieve fast dynamic response and a low total-harmonic-distortion (THD) with high power factor (PF). A load adaptive control scheme to maintain same dynamic response of the output voltage at different load conditions change. The proposed mixed-signal PFC control scheme has been verified by using computer simulation with experimental results to validate feasibility.