A GaN-based partial power converter with MHz reconfigurable switched-capacitor and RF SEPIC

This paper investigates a new reconfigurable switched-capacitor (SC) based partial power architecture which enhances the performance of radio frequency (RF) resonant DC/DC converters with gallium nitride (GaN) power devices. The proposed architecture has a comprehensive compatibility with existing RF and SC topologies and improves the performance of RF converters through partitioning of energy conversion stage and output regulation stage. Emerging new wide bandgap devices like GaN FETs enable a higher power density DC/DC converter design. A wider input range, larger voltage conversion ratio, smaller size, and excellent transient performance are expected. The prototype of the proposed GaN reconfigurable SC-based partial power RF converter comprises of a 20 MHz resonant single-ended-primary-inductor-converter (SEPIC) as a regulated stage and a high-efficiency 2 MHz reconfigurable SC as an unregulated stage. The GaN RF resonant SEPIC regulates the output using a robust ON/OFF control scheme, which enables fast transient responses. The high-efficiency GaN reconfigurable SC provides 1:1, 2:1 and 3:1 voltage conversion ratio which widens the input voltage range. The power stage of the prototype achieves a peak efficiency of 93 % and a power density of 963 W/in3 at 91.5 W.