Patent ID: 7113412

Claim:
A drive circuit comprising: a transformer having a primary winding to which a pulse is applied and a secondary winding, the secondary winding having one terminal connected to a reference terminal; a first switch element having a first control terminal, and switching between an output terminal and the reference terminal in response to said pulse; a first node provided between the other terminal of the secondary winding of the transformer and the first control terminal; a first diode connected between the other terminal of the secondary winding of the transformer and the first node; a first resistor connected between the first node and the first control terminal; a second diode, one terminal of the second diode connected to the reference terminal; a second switch element connected between the first node and the other terminal of the second diode, having a second control terminal and controlling a current flow of the second diode; a capacitor; and a second resistor, the capacitor and the second resistor being connected in parallel each other between the other terminal of the secondary winding of the transformer and the second control terminal.