A High Frequency Two-Stage Multilevel Converter with a Wide Output Range

This paper presents a two-stage multilevel converter which consists of a switched capacitor ladder and a four-phase buck converter. Similar as the classic multilevel converters, this work achieves a wide output range with reduced inductor voltage stress, enabling small inductors and high frequency operations. On the other hand, this work resolves the huge component count require by the typical multiphase multilevel converters, by providing multiple intermediate bus voltages. Therefore, this proposed work achieves a wide output range and high frequency operations with easy multiphase extensions. Designed in a 65 nm CMOS process, the proposed converter achieves a simulated 0.4 V -to- 1.3 V output range and peak efficiency 91.64% under 1.8 V input and 20 MHz single phase buck frequency. For load transient between 0 and 2 A with $2 \mathrm{~A} / \mathrm{ns}$ speed, the output voltage exhibits $+35 \mathrm{mV} /-35 \mathrm{mV}$ undershoot and overshoot, respectively.