Parallel Operation of SiC MOSFETs

Inhalt:
This work presents the issues and best design practices for paralleled MOSFETs, such as SiC MOSFETs. Because of fast switching and low switching power losses, SiC power switches have gained wide applications like drivetrain, EV chargers, server powers, and energy storage system. As load current and power increases, two or more SiC MOSFTs are paralleled to meet the application requirements. Compared with bipolar devices, MOSFETs are easier for parallel operation since they are driven by a voltage source. However, there are still some pitfalls that are best avoided. This paper will study the factors which affect the transient current and static current sharing and provide best design practices. These factors include the turn-on threshold voltage, internal gate resistor, turn-on resistance, and parasitic inductances due to PCB layout.