An Investigation into Challenges of a 1-MHz, 1-kW Buck Converter

High switching frequencies in converters significantly reduce the size of passive components, namely inductors and transformers, thus enabling high power density. However, these frequencies also introduce challenges such as semiconductor device reliability, thermal management, magnetic design, and electromagnetic interference. This paper discusses a dc-dc converter operating at 1 MHz and its associated design challenges. The relationship between GaN device on-resistance, junction temperature and losses in scenarios where the converter operates beyond its nominal design specifications is analyzed. Additionally, a PCB-based inductor is fully characterized and the parasitic effects of PCB traces are examined for a 1-MHz, 1-kW application. Finally, conducted and radiated emissions of the converter are addressed supported by simulation and hardware experimental measurements.