Abstract: False detection relating to overcurrent is prevented, and it is determined with no dead time whether or not the current of a main element is an overcurrent. By a gate signal indicating conductivity being applied to the gate of a sense element earlier than to a main element when the main element is caused to be conductive, and overshoot caused by a differential circuit of the sense element gate input portion being caused before current flows into the main element, it is possible to prevent false detection relating to overcurrent, and determine with no dead time whether or not the current of the main element is an overcurrent.

Abstract: A semiconductor element drive device includes a drive circuit which drives a semiconductor element configuring a power conversion device; an alarm generation circuit which generates alarm signals with pulse widths corresponding to protection factors in accordance with the outputs of detection circuits which detect information necessary for the operation of protecting the semiconductor element; an output circuit which externally outputs the alarm signals at a predetermined level; a protection cancellation circuit which generates a protection cancellation signal over a fixed period in accordance with the inverting output of a drive stop signal generation circuit, which stops the drive of the semiconductor element by the drive circuit in accordance with the outputs of the detection circuits, and with the output of the alarm generation circuit; and an output control circuit which changes the signal output level of the output circuit in accordance with the protection cancellation signal.

Abstract: False detection relating to overcurrent is prevented, and it is determined with no dead time whether or not the current of a main element is an overcurrent. By a gate signal indicating conductivity being applied to the gate of a sense element earlier than to a main element when the main element is caused to be conductive, and overshoot caused by a differential circuit of the sense element gate input portion being caused before current flows into the main element, it is possible to prevent false detection relating to overcurrent, and determine with no dead time whether or not the current of the main element is an overcurrent.

Abstract: A semiconductor element drive device includes a drive circuit which drives a semiconductor element configuring a power conversion device; an alarm generation circuit which generates alarm signals with pulse widths corresponding to protection factors in accordance with the outputs of detection circuits which detect information necessary for the operation of protecting the semiconductor element; an output circuit which externally outputs the alarm signals at a predetermined level; a protection cancellation circuit which generates a protection cancellation signal over a fixed period in accordance with the inverting output of a drive stop signal generation circuit, which stops the drive of the semiconductor element by the drive circuit in accordance with the outputs of the detection circuits, and with the output of the alarm generation circuit; and an output control circuit which changes the signal output level of the output circuit in accordance with the protection cancellation signal.