Design consideration of low to medium power dc-dc converter using enhancement-mode gallium nitride (e-GaN) HEMT device at MHz switching frequency for satellite payload power supply

Although silicon semiconductor substrate is perfect for power electronics since last 60 years, research scientists and semiconductor manufacturers have long searched for more robust alternatives to silicon for specific applications. Work on wide band-gap materials and devices have been going on for many years. The properties of these materials are very exciting to designers because wide band gap devices promise substantial performance improvements over their silicon based counterparts. These scientists have experienced varying degrees of success over the last few decades, but one strong contending alternative to silicon has emerged: gallium nitride (GaN). This paper discusses design consideration of low to medium power dc-dc converters operated at 500KHz to 1MHz switching frequency possible due to space grade GaN HEMT devices. A dc-dc converter prototype has been developed and performance has been analyzed. A brief comparison between silicon MOSFET based power supplies and GaN HEMT based power supply has been presented. The designed dc-dc converter is able to operate at 90 % efficiency with meeting all PARD performance for space applications.