A Dual-Mode Auto Switching and Wide Load Range High Efficiency AOT Buck Converter With Deep Sleep Mode Detector

This paper presents a dual-mode auto switching, adaptive on-time (AOT) buck converter with deep sleep mode detector (DSMD). The proposed deep sleep mode (DSM) can improve the efficiency under ultralight load conditions. And the proposed DSMD allows the buck converter to automatically switch between DSM and Pulse Frequency Modulation (PFM). Furthermore, an improved adaptive on-time generator is proposed that can operate at an input voltage of 8.4 V while maintaining low quiescent current. The proposed buck converter was implemented by using a $0.18-\mu \mathrm{m}$ BCD process. The input voltage range and regulated output voltage are $4-8.4 \mathrm{~V}$ and 3.3 V for 1 uA to $100 \mathrm{~mA}(100,000 \mathrm{X})$ load range. In order to enable the converter input voltage to span medium and low voltages, this work incorporates an internal charge pump (CP) and low dropout regulator (LDO). The simulation results show the converter can achieve a $92.5 \%$ peak efficiency and the efficiencies can be greater than $\mathbf{8 8 \%}$ from $\mathbf{1 m A}$ to $\mathbf{1 0 0 ~ m A}$.