A 230-nA Quiescent Current and Enhanced Transient Performance DC-DC Converter with Suppressed Under/Overshoot for IoT SoCs

This paper presents a low quiescent current, transient-enhanced DC-DC buck converter with an overshoot and undershoot suppression scheme, designed to support low-power SoCs. To decrease undershoot or overshoot voltage during rapid load current transitions, an overshoot and undershoot voltage detection and response scheme is proposed. The buck converter employs an adaptive constant on time control mode, and to achieve automatic transition between PWM and PFM modes, a sub-threshold zero current detector(ZCD) is introduced. To reduce quiescent current and improve efficiency under light loads, a sampling-based low-power voltage reference circuit is proposed. Implemented with a 55 nm CMOS process, the buck converter operates with a load current range of 10 μA-10 mA. It achieves a quiescent current of 230 nA and a peak efficiency of 93.2%. During a 10 mA load variation, the converter exhibits an undershoot of 36 mV and an overshoot of 34 mV.