A Variation-Tolerant 1.25-MHz Multi-Resonant GaN Switched-Capacitor DC/DC Converter

Abstract

Minimizing the size of passive components in DC/DC converters often leads to higher switching frequencies and losses. Resonant Switched Capacitor Converters (ReSCCs) mitigate losses by incorporating a flying LC tank and zero-current switching, but their efficiency is sensitive to component variations. To address this limitation, Multi-Resonant Switched Capacitor Converters (MuReSCCs) introduce a second resonance loop to preserve energy during switching. This paper presents the design and validation of a 48 V-to-lower-voltage MuReSCC, with a particular focus on robustness against variations in component parameters. A complete implementation of the power converter is proposed, supported by analytical models and design guidelines. Moreover, on-off control for output voltage regulation is implemented, and its impact on efficiency is investigated. Unlike previous works, this study targets operation at switching frequencies above 1 MHz through Gallium Nitride (GaN) devices and a planar printed circuit board (PCB) inductor. Experimental results, supported by theoretical models, demonstrate a peak efficiency above 98.9% at 45 W and a maximum observed output power of 200 W, with an efficiency of 94%. The immunity to variations in component parameters is experimentally verified. The efficiency of the MuReSCC decreases by less than 1% for deviations of up to $\pm$ 30% in resonant component values.