Challenges for fully-integrated resonant switched capacitor converters in CMOS technologies

Abstract

Switched capacitor (SC) converters inherent losses limit the achievement of high efficiencies at high power densities for on-chip context. Hence, techniques are being investigated to enhance the deficient capacitance energy utilization. The resonant switched capacitor (ReSC) converters showed up as a promising candidate for efficient, dense, granular on-chip power supplies. In this paper, we discuss the design of ReSC converter employing integrated on-chip inductance in CMOS technology. We focus on a 2-phases 2:1 ReSC converter with single inductor. We discuss the practical constraints on using the on-chip air-core inductor and how it is going to affect the area of the converter. Using different inductor implementations, we compare the performance of the ReSC and SC converters of the same area. The results point towards the advantage of ReSC converter over the SC converter in case of using an inductor with relatively small area and negligible contact resistance which could be obtained in the 3D technology.I.