A hysteretic buck DC-DC converter achieving 90% peak efficiency with light-load current of 0.1–10 mA

A buck DC-DC converter with very high light load efficiency is presented in this paper. It introduces hysteretic control when the large output ripple problem is not critical, especially in light-load condition. Moreover, a fast-response zero current detector (ZCD) is adopted to make the converter work in discontinuous conduction mode (DCM). Due to hysteretic control extremely simplified the control circuits, the converter is divided into two independent loops, which further simplifies the optimization of power consumption. The proposed converter is fabricated in a standard 55 nm CMOS process. It converts 1.8-2.5 V battery voltage into a stable output voltage of 1 V, and offers 100μA to 10mA light-load current output. The hysteretic converter achieves peak efficiency of 88.5% and 90%, with a supply voltage of 2.5 V and 1.8 V, respectively.