An ultrafast overcurrent protection scheme for power MOSFETs switches

Abstract

ABSTRACT Ultrafast overcurrent protection (OCP) prevents peak fault current reaching at a very high level and hence peak power dissipation and turn-off transient voltage stress on the power device are reduced. In this paper, a direct driver shutdown technique is proposed for ultrafast over current protection for power MOSFETs. The key advantage of this technique is that, delay due to logic gates and input control flip-flop is avoided and the response time of the OCP circuit is reduced. The analysis is presented to prove the concept. By simulation and experimentation, it is shown that the response is ultrafast and there is no spurious or recurrence of switching pulses from the driver IC output when it is directly shutdown before the input control flip-flop is reset. The operation of the proposed OCP circuit is verified under short-circuit condition by simulation as well as by experimentation. Response time of less than 100 ns and fault current clearance time of less than 180 ns are obtained.