A comparative analysis of Switched-Capacitor and inductor-based DC-DC conversion technologies

Abstract

This paper compares the performance of Switched-Capacitor (SC) and inductor-based DC-DC conversion technologies. A metric to compare between the two topologies is discussed, and is used to compare switch utilization. Fundamental limits on utilization of reactive elements developed in the literature for all DC-DC converters are also reviewed and discussed, and this analysis shows that popular SC and inductor-based converters achieve the limits of utilization for reactive components. These limits are stated in terms of the ratio of output power to required stored energy in reactive elements. A detailed analysis of available surface mount discrete components and on-die devices reveals that capacitors have substantially higher energy and power density than their magnetic counterparts. The challenging regulation task for SC converters is also discussed, with a promising strategy outlined. The SC converter is evidently a promising candidate for future high power density integrated DC-DC converters.