Buck converter with higher than 87 efficiency over 500nA to 20mA load current range for IoT sensor nodes by Clocked Hysteresis Control

摘要

This paper presents a buck converter that achieves an almost flat conversion efficiency higher than 87% over the load current ranging from 500nA to 20mA. A leakage-based oscillator and a newly proposed double-half frequency control algorithm are introduced to provide a clock signal that triggers a hysteresis control, which is called Clocked Hysteresis Control (CHC). By removing continuously-on comparators in the conventional hysteresis control, the buck converter improves the conversion efficiency under light load current conditions while maintaining a fast transient response. The conversion efficiency of 87.7% at 1mA and 90.4% at 1μA are achieved. Compared with state-of-the-art buck converter, the efficiency at 1μA is improved 12% to 34%.