A continuous switching mode step-down switched-capacitor regulator with inrush current control scheme

Abstract

Switched-capacitor based regulator has its unique usage in various power management applications where both small foot print and flexible current capability is required since the switched-capacitor power stage is scalable with current rating and thus opens possibility of fully on-chip implementation whereas inductor based regulator is very limited by inductor size due to the only availability of off-chip inductor that can be used by relatively low switching frequency regardless of current capability. Thus switched-capacitor based regulator is very suitable for IoT application, where multiple power rail is needed but PCB size is very limited and external components are limited. In this paper, a 1/2 step-down power stage is introduced, analyzed. Furthermore, problem with the phenomena associated with switched-capacitor regulators is described and the scheme to overcome the issue. A full regulator architecture that regulates the inrush current is introduced and simulation results shows that the output ripple is greatly reduced compared to an open loop step down switched-capacitor power stage.