A 4.5V-Input 0.3-to-1.7V-Output Step-Down Always-Dual-Path DC-DC Converter Achieving 91.5%-Efficiency with 250mΩ-DCR Inductor for Low-Voltage SoCs

Abstract

This paper presents an always-dual-path (ADP) DC-DC converter that achieves 4.5V-input 0.3-to-1.7V-output buck conversion for battery-powered low-voltage SoCs. Regardless of voltage conversion ratio (VCR), the proposed ADP converter maintains the inductor current constantly to be ×0.5 of the load current, bringing high efficiency with a large DCR of the compact-volume inductor. Seamless dual-power-path formed by two flying-capacitors merits a low ripple. The chip fabricated in 180-nm 5V CMOS obtains an efficiency of 91.5% (84.6%) at a VCR of 0.38 (0.2) even with an inductor DCR of 250mΩ.