Design aspects of multi-phase interleaved resonant switched-capacitor converters with mm-scale air-core inductors

This work explores design aspects of resonant switched-capacitor converters with respect to multi-phase interleaving and inductor design. In high-density or silicon-integrated ReSC converters, interleaving can not only significantly improve output voltage ripple but also efficiency and power density by reducing bypass capacitance requirements and thus providing more area for flying capacitance. An analytical approach to analyze voltage ripple in multi-phase designs is presented. Moreover, a design methodology for miniature air-core inductors for a multiphase ReSC converter is described and design trade-offs are discussed. Results of the ripple analysis and inductor design are compared with measurement results from a three phase ReSC prototype IC in 180 nm CMOS.