Patent ID: 8344762

Claim:
A gate driving circuit for driving switching element having a gate input capacitor comprising: a primary circuit; and a secondary circuit, wherein the primary circuit comprises: a direct-current power supply; a primary winding; a first switching element connected between a first end of the primary winding and a positive electrode of the direct-current power supply; a first unidirectional element connected in parallel with the first switching element so that a forward direction of the first unidirectional element is toward the positive electrode of the direct-current power supply; a second switching element connected between a second end of the primary winding and a negative electrode of the direct-current power supply; and a second unidirectional element connected in parallel with the second switching element so that a forward direction of the second unidirectional element is toward the other end of the primary winding, wherein the secondary circuit comprises: a secondary winding; an inductance element; a third switching element; and a third unidirectional element connected in parallel with the third switching element, the secondary circuit being configured so that the secondary winding, the inductance element, the third switching element, and the gate input capacitor form a closed circuit, the secondary winding being magnetically coupled to the primary winding to form a transformer, the first switching element and the second switching element are configured to charge the gate input capacitor, the third switching element is configured to discharge the gate input capacitor, when the first switching element and the second switching element are on, in the primary circuit, a first current flows through the first switching element and the second switching element, in the secondary circuit, a charge current generated based on the first current flows through the third unidirectional element, and when the third switching element is on, in the secondary circuit, a discharge current flows through the third switching element, in the primary circuit, a second current generated based on the discharge current flows through the first unidirectional element and the second unidirectional element.