Smart Self-Driving Multilevel Gate Driver for Fast Switching and Crosstalk Suppression of SiC MOSFETs

Wide-bandgap devices, such as silicon carbide and gallium nitride, have high switching speed potential. However, the actual speed in practical application is limited by circuit parasitics and interaction between high-side switch and low-side switch in a phase-leg configuration, known as crosstalk effect. This article proposes an isolated voltage source gate driver with crosstalk suppression capability to take full advantage of the inherent high switching speed ability of silicon-carbide devices. By applying variable gate voltage through the auxiliary circuit, the crosstalk problem can be mitigated. Using the original gate-source voltage as auxiliary circuit driving signal, the gate driver does not introduce any extra control signals, which avoids additional signal/power isolations and makes the auxiliary circuit very convenient to be implemented on the existing commercial gate driver. The auxiliary circuit makes the gate voltage rise from 0 V other than -5 V when the switch turns on, leading to faster switching speed and lower switching loss compared with a traditional gate driver. LTSPICE simulation and double pulse test experiment based on 1.2-kV/60-A silicon-carbide MOSFETs are conducted to evaluate the crosstalk suppression capability of the proposed gate driver.