This paper presents the design of a fault detection circuit applied to a silicon carbide Mosfet (SiC-Mosfet). Fault detection is done by monitoring the behavior of the gate signal. The most important characteristic that has been reported in literature is quick detection since the evaluation is done while the SiC Mosfet is turning-on. With this method fast detection is allowed for short-circuit and open-circuit failure with small times for detection which prevents to spread the failure to the full system. To validate the fault detection circuit a boost converter with SiC-Mosfet was designed. Experimental results validate the reliability of the proposal.