An Adaptive Digitally Tuned Flash-based LDO with Reduced Hardware for Sensor Nodes in WBAN

This paper presents a digital adaptive flash-based low dropout regulator (LDO) for integration with a power management unit (PMU) in a sensor node system-on-a-chip (SoC). The proposed LDO integrates an exponentially varied flash-based undershoot and overshoot detector that inherently covers a wide range of reference voltages. Adaptive multi-voltage scaling is obtained with the proposed LDO by generating a regulated voltage in two specific modes with different load condition. A fast transient response is observed due to exponentially varied flash-based structure of reference voltage and corresponding digitally triggered MOS array. The digital LDO is implemented in 180nm CMOS technology node and it produces a regulated output voltage of 0.7 V with settling time of 25 ns. The simulation results show the peak current efficiency to be 96% with maximum load current and clock frequency being 10 mA and 40 MHz, respectively.