Switched-capacitor DC/DC converters with resonant gate drive

In this paper, we examine how switched-capacitor (SC) converters can be used in low-voltage low-power DC/DC applications with power management. Analysis of losses is presented to facilitate SC converter design and optimization. A resonant gate drive is proposed to reduce switching losses and simplify control of switches in SC converters. A closed-loop controller is designed to enable and disable oscillations of the resonant gate drive so that the output DC voltage is well regulated down to zero load and so that high efficiency is maintained for a very wide range of loads. Results are experimentally verified on two low-power (0.2 and 5 W) five-one step-down converters with regulated 3 Vdc output and efficiency greater than 80% in a 100-1 load range.