Gate drive circuit for a semiconductor switch

摘要

The present application is directed to drive arrangement for semiconductor switches and in particular to a method of driving the gate of a switch with pulses corresponding to turn-on and turn-off commands through separate turn-on and turn-off transformers. The application provides a fail safe reset feature, a more efficient turn-on circuit and an energy recovery circuit for recovering energy from the gate upon turn-off. The application also provides a novel arrangement for assembling multiple pulse transformers on a circuit board.

主权项

1. A gate drive circuit for controlling the operation of a first semiconductor switch having a gate, the isolated gate drive circuit comprising:
a first transformer that transfers a first pulse from a primary side of the first transformer to a secondary side of the first transformer; a first rectifier for providing the transferred first pulse directly to the gate of the first semiconductor switch to cause the semiconductor switch to be turned on; a second semiconductor switch, which, in a first state, clamps a gate voltage of the first semiconductor switch, and, in a second state, is open; a reset circuit that is triggered by the arrival of the first pulse to place the second semiconductor switch in the second state upon an arrival of the first pulse, wherein the reset circuit includes a timer responsive to the arrival of the first pulse, and wherein the reset circuit is configured to turn off the semiconductor switch within a predefined interval after the arrival of the first pulse; and a second transformer that transfers a second pulse from a primary side of the second transformer to the secondary side of the second transformer, wherein the reset circuit is configured to turn off the first semiconductor switch in response to the arrival of the second pulse irrespective of whether the predefined interval has expired.