The present invention discloses a circuit and method for detecting a fault current in a circuit containing a power transistor. A comparator in communication with a parasitic inductance is utilized to sense the excessive change in current through the power transistor. When the voltage magnitude through the parasitic inductor exceeds a predefined limit, the comparator triggers a gate drive circuit. The gate drive circuit is in communication with the power transistor. The gate drive circuit shuts off the power transistor when the predefined limit is reached. Thus, the present invention is capable of reacting quickly to fault currents through the power transistor thereby protecting the transistor and other circuit components from damage.