Patent ID: 8421505

Claim:
A drive circuit for alternately turning on first and second semiconductor switches that are connected in series, comprising: a first series circuit including a capacitor and a primary winding of a transformer, the capacitor and the primary winding of transformer being connected in series; a first secondary winding of the transformer, configured to generate a voltage based on the pulse signal and apply the voltage to a control terminal of the first semiconductor switch, the first secondary winding being wound in a direction opposite to a direction in which the primary winding is wound; a second secondary winding of the transformer, configured to generate a voltage based on the pulse signal and apply the voltage to a control terminal of the second semiconductor switch, the second secondary winding being wound in the same direction as the direction in which the primary winding is wound; a pulse signal generator connected to both ends of the first series circuit and configured to generate the pulse signal as a control signal of the first and second semiconductor switches for output to the first series circuit; and a third semiconductor switch connected in parallel to the capacitor; wherein when the drive circuit receives a stop signal, the pulse signal generator stops the generation of the pulse signal and the third semiconductor switch is turned on by the stop signal, thereby an ON period of the first semiconductor switch is shortened.