An experimental VHF DCIDC converter aimed at envelope-tracking amplifiers for space applications is presented. Based on Gallium Nitride components, it is capable of operating in the range of tens of watts, as required by on-board transmitters. When driven by a 50-MHz PWM signal, it reaches a peak efficiency of 91.6%. A detailed breakdown of the associated losses is reported in order to identify the contributions. Additional measurements at 67 MHz show a peak efficiency of 89.8%.

Keywords«Gallium Nitride (GaN)», «High frequency power converter», «Schottky diode», «Silicon Carbide (SiC)». AbstractThis paper presents two buck converters switching at 50 MHz and based on Gallium Nitride dice. The first converter features a diode designed for power applications and demonstrates 87.9% peak efficiency. The diode mounted on the second one is aimed at higher-frequency operation and brings this value up above 91% in the same operating conditions. Loss contributions are evaluated, showing the influence of the diode alone on the efficiency of such converters.