4MHz to 15MHz Radhard Hybrid CMOS/GaN Buck Converter with 88.6 Percent Peak Efficiency

This paper presents a hybrid CMOSGaN buck converter that exhibits up to 88.6 percent measured peak efficiency operating at switching frequencies of 4MHz to 15MHz, with a high conversion ratio from an input voltage of 14V to an output of 1.5V 6A 5V 5A. This work presents an integrated CMOS gate driver solution in 0.35um CMOS. The CMOS integrated circuit IC includes the gate driver and the closed-loop controller for directly driving a GaN power stage. The presented controller technique uses voltage mode control with an innovative cascode driver architecture to allow 3.3V CMOS devices to effectively drive GaN devices that require 5V gate signal swing. Furthermore, the power converter is designed to operate under 400MRad of total dose, thus enabling its use in high-radiation environments.