The introduction and wide adoption of REduced SURface Field (RESURF) Power MOSFETs (aka, charge balance MOSFETs) has required the need to reassess how hard switching events are being handled in various applications. This paper will focus on how RESURF Silicon and GaN Power MOSFETs are parametrically characterized for switching charge (QSW) and compare results. We will then compare total switching losses (QSW + EOSS) for three MOSFET technologies (1. GaN MOSFET; 2. Si MOSSFET #1; 3. Si MOSFET #2) on a hard-switched power supply application. All three MOSFETs will be closely matched for On Resistance (RDSON) to allow for a normalized comparison of the switching losses. We will conclude by analyzing the measured application results and will have a general discussion on the impact of hard-switched losses.
