Patent ID: 7212036

Claim:
A driving apparatus for driving an H bridge circuit, comprising: a driving circuit for outputting a driving signal to a semiconductor switching-device included in the H bridge circuit; an over-voltage detection circuit for detecting an over-voltage applied to the H bridge circuit; and a control circuit for controlling the driving circuit to output a driving signal to all semiconductor switching-devices included in the H bridge circuit to put the semiconductor switching-devices in an electrically non-conductive state, wherein: the H bridge circuit includes a P-channel MOSFET as a semiconductor switching-device provided on a power supply side; the driving circuit includes a power supply side driving device disposed between a power supply and a gate of the P-channel MOSFET, and a ground side driving device disposed between the gate and the ground, wherein: the driving circuit drives the P-channel MOSFET by selectively putting either the power supply side driving device or the ground side driving device in an electrically conductive state; when the over-voltage detection circuit detects an over-voltage, the power supply side driving device is put in an electrically conductive state; and when the over-voltage detection circuit detects an over-voltage, the ground side driving device is put in an electrically non-conductive state; and the driving circuit further includes a Zener diode, which is connected between a power-supply-side terminal and an electrical-conduction control terminal of the ground side driving device, wherein the Zener diode has a Zener voltage not higher than a withstand voltage of the ground side driving device.