Improving the power density of a power converter has many benefits for systems integration. Aspects such as
thermal management, weight, conformation to mounting locations, and the footprint of the converter all become
critical factors as systems continue to scale down in size. The flying-capacitor multilevel (FCML) converter topology
is of interest because it has characteristics which contribute to high power density. This work presents a quasisquare-
wave (QSW) zero-voltage switching (ZVS) multilevel DC-DC converter. ZVS greatly reduces switching
losses and enables high frequency operation of the converter. A hardware prototype is implemented, built on a
flexible polyimide substrate circuit board. Experimental results show a peak efficiency above 98.5%, an effective
switching frequency of up to 3 MHz, and a power output of 250 W.