Ultra-low quiescent current off-chip capacitor-less low-dropout linear regulator with enhanced load-transient response for low-power IoT devices

Abstract This paper presents an off-chip capacitor-less low-dropout linear regulator (LDO) that incorporates a bias current generator (BCG) along with a current control circuit, a voltage monitor, and a voltage comparison circuit. The enhancements significantly improve load transient response and prevent overcurrent during startup, addressing key limitations of conventional BCG-based designs. Measurement results demonstrate stable operation with a 1.2 V output and a quiescent current of 128 nA, achieving line regulation of 1.36 mV V −1 and load regulation of 3.55 mV mA −1 . The LDO is capable of sustaining operation with up to a 20 mA load current without the need for off-chip capacitors, reducing system cost and size while ensuring reliable performance for ultra-low-power applications.