Two-Stage Piezoelectric Resonator / Switched Capacitor DC-DC Converter

Magnetics pose a significant challenge for power converter miniaturization. Approaches to address this include power converters based on piezoelectric resonators (PRs) rather than magnetics, and switched-capacitor (SC) converters which utilize only capacitors. However, PR-based converter efficiencies tend to decrease at high voltage conversion ratios, and purely SC-based converters are not capable of efficiently regulating voltage. Through the hybridization of PR and SC-based converters, there is an opportunity for each to address the drawbacks of the other to create a high power density, high efficiency power converter for applications requiring high voltage conversion ratios and wide, continuous voltage conversion ranges. In this paper, we propose a two-stage dc-dc converter with a PR-based regulation stage and a SC-based transformation stage. We detail a new simplified eight-stage switching sequence for the PR stage and experimentally validate this concept in a prototype converter.