Comparison of the Capacitances and Switching Losses of 1.2 kV Common-Source and Common- Drain Bidirectional Switch Topologies

Bidirectional, or four-quadrant switches (FQS) can be designed as back-to-back MOSFETs connected in common-drain (CD) or common-source (CS) topologies. CDFQS and CS-FQS assembled from discrete 1.2 kV commercially available SiC power MOSFETs were characterized to obtain capacitance and switching loss values. The CD-FQS exhibited a 1. 17x larger turn-on loss compared to the CS-FQS, while the CS-FQS exhibited a 1. 52x larger turn-off loss compared to the CD-FQS. The CS-FQS exhibited a lower input capacitance, while the CD-FQS exhibited a lower output and reverse transfer capacitance.