PWM-Controllable High Step-Down Switched Capacitor Converter

Abstract

Although switched capacitor converters (SCCs) offer high power density and a miniature footprint, applications of SCCs have been mainly limited to unregulated converters because the voltage conversion ratio of conventional SCCs is basically not controllable. This paper proposes a PWM-SCC that provides PWM-controllable high step-down voltage conversion. In comparison with a traditional buck PWM converter, the proposed PWM-SCC achieves higher step-down voltage conversion at a given duty cycle. An experimental test on a 30-W prototype for a 28-V input and a 6.0-V output achieved a power conversion efficiency of higher than 86% in the output power range of 10-30W with a duty cycle of 0.40-0.46.