A 180 nA Quiescent Current Digital Control Dual-Mode Buck Converter With a Pulse-Skipping Load Detector for Long-Range Applications

A digitally controlled dual-mode buck converter using low quiescent current is proposed in this work. In particular, the proposed dual pulse-skipping mode adopts a pulse-skipping adaptive on-time (PSAOT) mode for heavy load; and a pulse-skipping asynchronous mode (PSAM) for light and ultra-light loads to achieve a 100,000X wide load range for the Long-range (LoRa) application. Specifically, the pulse-skipping mode selector adopts a digital logic circuit to realize the 180nA low quiescent current. In addition, a low-power dynamic comparator with an adjustable offset is used to accelerate the transient response. The proposed converter is fabricated in a TSMC 350 nm CMOS process and results in an output voltage of 3.3 V from 5V to 4.2 V input voltage range. These results show that the overall system achieves 92.9 % peak eficiency at 8 mA output load and a figure of merit (FoM) of 2.29.