A 240-nA Quiescent Current, 95.8% Efficiency AOT Controlled Buck Converter With A 2 -Comparator and Sleep-Time Detector for IoT Application

An ultralow-quiescent current dc–dc buck converter with a single controller is presented to achieve high efficiency over a wide load range for Internet of Things application, which is achieved by utilizing adaptive on -time control topology. An on-demand modulation strategy and sleep-time detector are proposed to attain sub-μA quiescent current consumption under ultralight load condition. The adaptive-bias and adaptive-gain (A2) comparator is presented to improve the loop stability caused by the inherent propagation delay of the low-power comparator. Moreover, a novel on -time generator is proposed to fix the switching frequency in continuous conduction mode. The proposed buck converter was implemented by using a 0.18- μ m CMOS process with an area of 1.092 mm2. It achieves a peak efficiency of 95.8% and >90% efficiency from 10 μA to 300 mA. A 240-nA quiescent current, including bandgap voltage and current reference, is achieved. With a low output ripple of less than 20 mV, the input voltage range and regulated output voltage are 2.1–5.5 and 1.8 V, respectively.