Three-level buck converter utilizing a DAC-based flying capacitor voltage control technique

Abstract

This paper proposes a three-level buck converter utilizing a Digital-to-Analog Converter (DAC)-based flying capacitor voltage control technique, which controls the voltage on a flying capacitor with a differential difference amplifier and common mode feedback circuit for stable operation. Employment of the DAC-based flying capacitor voltage control circuit allows the proposed circuit to compensate for the inductor voltage error as the load current varies. The proposed three-level buck converter was implemented with a CMOS 180 nm standard process. The measurement results demonstrate the wide range of the input and output voltage from 2.7 V to 3.6 V and 0.7 V to 2.4 V, respectively. The proposed three-level buck converter achieved the peak power efficiency of 91% and output ripple voltage of 32.5 mV at the switching frequency of 2 MHz and load current range of 10 mA to 400 mA.