Patent ID: 9627973
Date: 2017-04-18
CPC Classifications: H02J,H02M,H03K,Y02B,Y02E

Claim:
1. A switching power supply device comprising: a first transistor including a first electrode connected to a first node; a second transistor including a first electrode connected to a second electrode of the first transistor, and a second electrode connected to a second node; a driving circuit that turns on the first and second transistors when a current flows from the first node to the second node, and turns on the first transistor while also turning off the second transistor when a current flows from the second node to the first node; a first delay circuit, connected between a control electrode of the first transistor and the driving circuit, that delays a potential variation of the control electrode of the first transistor; and a second delay circuit, connected between a control electrode of the second transistor and the driving circuit, that delays a potential variation of the control electrode of the second transistor, wherein each of the first and second transistors includes a parasitic diode connected in a forward direction between the second and first electrodes; a withstand voltage between the first and second electrodes of the first transistor is higher than a withstand voltage between the first and second electrodes of the second transistor, the driving circuit turns on the first transistor by applying to the control electrode of the first transistor a voltage that is higher than a voltage obtained by adding a threshold voltage of the first transistor to a voltage of the second node; and at least one of the first delay circuit and the second delay circuit includes a structure that causes a potential of the control electrode of the first transistor or the control electrode of the second transistor to be increased and decreased at different speeds.