Resonant Switched Capacitor DC-DC Converter with Stackable Conversion Ratios

As the demand for fully integrated power management system has increased in recent years, the switched-capacitor (SC) converter has shown exceptional promise due to the favorable energy density of capacitors, but its limited output range and its intrinsic charge-sharing loss have limited its range of applications. In this paper, a resonant switched-capacitor (ResSC) topology is presented as a way to improve on the SC methodology. The topology can be stacked to any N-to1 conversion ratio with only a single inductor. A phase shift operation is adopted to enable a wide output range while maintaining high efficiency. The load regulation is maintained with frequency modulation. The controller is designed with the aid of current phase compensation in addition to the voltage mode control. A prototype of a nominal 4-to-1 ResSC has been built and tested. The control and the regulation of the output voltage are verified through experiment.