Patent ID: 8878572
Filing Date: 2014-11-04
Classification: H03K

Abstract:
1. A drive control apparatus for a semiconductor device having an insulated gate type transistor structure and a diode structure, which are disposed in a same semiconductor substrate, wherein the semiconductor device includes an energization electrode of the transistor structure and an energization electrode of the diode structure, which are provided by a common electrode, and wherein a gate drive voltage is applied to the insulated gate type transistor structure, the drive control apparatus comprising: a current detection device for outputting at least a current detection signal, which corresponds to a current flowing through the diode structure; and a control device, wherein: the control device applies the gate drive voltage to the semiconductor device when an on-instruction signal is input in the control device; the control device compares the current detection signal with a current threshold value preliminary set in a forward direction of the diode structure during a first period, in which the on-instruction signal is input in the control device, after a second period has elapsed from first time, at which the control device applies the gate drive voltage, or second time, at which the control device shuts off the gate drive voltage; a transient variation caused by a change of a gate drive state is generated on the current detection signal in the second period; the control device shuts off the gate drive voltage when the current detection signal is equal to or larger than the current threshold value; and the control device applies the gate drive voltage when the current detection signal is smaller than the current threshold value.