The relatively recent introduction of Silicon Carbide (SiC) MOSFET devices with voltage ratings in the range of 650 V – 750 V cleared the way for hard switching operation in bridgeless half bridge topologies such as the Continuous Conduction Mode (CCM) Totem Pole. This topology de-facto enabled power supplies designers to push the efficiency of the Power Factor Correction (PFC) stage to 99% and above while sticking to a relatively simple control strategy. Whereas Super Junction (SJ) MOSFETs are typically driven with 0 V off state voltages (unipolar driving), SiC MOSFETs datasheets often recommend the usage of negative off state voltages (bipolar driving) to avoid unwanted spurious turn on effects, this comes the expense of an increased BOM count and design/layout complexity. This talk will present a comparison of the switching energies of commercially available SiC MOSFETs driven with unipolar and bipolar driving to quantify the performance difference between these two driving schemes.
