A Fully-Integrated 0.9W/mm279.1%-Efficiency 200MHz Multi-Phase Buck Converter with Flying-Capacitor-Based Inter-Inductor Current Balancing Technique

Abstract

This paper presents a fully-integrated (highly-integrated) 0.9W/mm2 (1.01W/mm2) 79.1% (81.4%)-efficiency 2-phase buck converter using on-chip (bond-wire) inductors and a 88.1%-efficiency 4-phase one with external components. They feature in-channel and inter-channel current self-balancing enabled by using flying-capacitor that is mainly aimed to lower the switching voltage. Also, the charge-recycling gate driver is proposed. The chips fabricated in a 55nm CMOS achieve a 45V/s DVS rate and a transient slew rate of 9A/s.