Power transistor drive circuit with improved short circuit protection

Abstract From the Canadian patent

A gate drive circuit for an insulated gate bipolar transistor initially drives the gate to a first voltage potential which causes the transistor to partially turn on. A sensor detects when the transistor saturates, at which point the gate drive voltage is increased to increase the conductivity of the transistor and reduce its saturation voltage drop. If however, a load coupled to the transistor is short circuited, the transistor will never reach saturation and will remain partially turned on at a point where it has increased short circuit current handling capability. In addition, once the transistor has been fully turned on, should a short circuit load condition occur, the transistor will …