Patent ID: 8310296

Claim:
A driving transistor control circuit for controlling ON and OFF of a voltage-controlled type driving transistor connected in series with an electrical load between a power supply voltage and a ground, the driving transistor being defined as a primary driving transistor, the driving transistor control circuit comprising: a secondary driving transistor connected in parallel with the primary driving transistor and smaller in size than the primary driving transistor; and an energization control circuit configured to turn ON the primary driving transistor by turning ON the secondary driving transistor before the primary driving transistor is turned ON, the energization control circuit being configured to turn OFF the primary driving transistor by turning OFF the secondary driving transistor after the primary driving transistor is turned OFF, wherein the energization control circuit includes a first control transistor, a second control transistor, a first resistor connected between a control terminal of the first control transistor and a control terminal of the secondary driving transistor, a second resistor connected between the control terminal of the secondary driving transistor and a control terminal of the primary driving transistor, and a third resistor connected between the control terminal of the primary driving transistor and a control terminal of the second control transistor, the first control transistor is configured to apply a first voltage to the control terminals of the primary and secondary driving transistors to turn ON the primary and secondary driving transistors in response to a first external control signal instructing the primary driving transistor to be turned ON, and the second control transistor is configured to apply a second voltage to the control terminals of the primary and secondary driving transistors to turn OFF the primary and secondary driving transistors in response to a second external control signal instructing the primary driving transistor to be turned OFF.