4.4 Rectifiers

There has been a continuous trend toward higher operating frequencies especially in motor control and switch mode power supplies. In motor control circuits, operation at frequencies above the acoustic range is attractive for consumer application. In power supplies, operation at high frequencies is attractive because of the reduction in size and power losses in the passive components (inductors and capacitors) which leads to a more efficient, compact system design. To accomplish higher frequency operation it is essential to use power rectifiers with improved switching performance. SiC's electronic parameters superiority would enable dramatic improvement in this regard. There are three classes of SiC power rectifiers as illustrated in Section 4.1:

• Schottky diodes which offer extremely high switching speed but suffer from high leakage current;
• PiN diodes which offer low leakage current but show reverse recovery charge during switching and have a large junction forward voltage drop due to the wide band gap of SiC;
• merged PiN Schottky (MPS) diodes which offer Schottky-like on-state and switching characteristics, and PiN-like off-state characteristics.

T. Ayalew: SiC Semiconductor Devices Technology, Modeling, and Simulation