Monolithic very high frequency GaN switched-mode power converters

This paper describes very high frequency (10–200 MHz) switched-mode power converters using custom GaN chips with integrated power switches and gate drivers, allowing standard logic-level PWM control inputs. Circuit design techniques are described in depletion-mode 0.15μm RF and 0.25μm switch GaN-on-SiC processes, including integration of gate-drive and level translation circuits. Operating from up to 25 V dc input voltage, efficiencies exceeding 90% are demonstrated at switching frequencies up to 100 MHz and at power levels exceeding 10 W. When used as an envelope-tracking drain supply modulator for high-efficiency RF transmitters, a monolithic two-phase 25 V, 10 W GaN converter prototype achieves 20 MHz large-signal tracking bandwidth with 89.7% average power-stage efficiency.