10 MHz PWM converters with GaAs VFETs

Switching speeds of currently available power switches have limited pulsewidth modulation (PWM) techniques to 1 to 2 MHz. High-speed (<2 ns switching) GaAs vertical field-effect transistors (VFETs) have overcome the limitation. These devices have been incorporated in 10 MHz, PWM, boost and buck 5 W power stages that have demonstrated good efficiencies (>85%) and very high power densities (500 W/in./sup 3/).