A Self-Adjustable Blanking Time Short Circuit Protection Circuit for SiC Power MOSFETs

This paper proposed a self-adjustable blanking time short circuit protection circuit for SiC power MOSFETs. This circuit consists of a variable blanking time module and a short circuit (SC) detection module. It can automatically set the detection delay for hard switching fault (HSF) and respond quickly to shut down the SiC MOSFET under SC situations. The proposed SC protection circuit does not require a blanking capacitor and can be integrated into the gate driver IC. The proposed SC protection circuit is designed using X-FAB's 0.35 µm BCD technology and is verified using Spectre simulations. HSF and fault under load (FUL) conditions can be quickly detected by the proposed SC protection circuit. With a 600 V bus, the default detection delay is 133 ns for the HSF occurring in the first switching cycle. The detection delay can be varied from 76 to 111 ns by changing the gate resistance
$R_{G}$
from 5 to 25 Ω for the subsequent occurrence of HSF. The detection delay for FUL is 52 ns, and it is not affected by
$R_{G}$
.