A Compact Programmable LDO Regulator for Ultra-Low Voltage SoC

Abstract

This paper proposes a compact programmable low dropout (LDO) regulator for an ultra-low voltage system-on-a-chip (SoC) using the voltage scaling technique. Two innovative design concepts were proposed: a programmable multi-level resistor array that can precisely tune the ratio of the feedback resistor divider; and a current limiter that limits a small static current flowing through the resistor network while reducing the occupied area. Experimental results show that the monotonic 50-step programmable output ranging from 0.3 V to 0.8 V is achieved, with an input of 1 V and a maximum load current of 100 mA. The occupied area is only 0.017 mm².