| 摘要 |
PROBLEM TO BE SOLVED: To reduce switching loss in a step-up/down type DC-DC converter transferring power from the low voltage side to the high voltage side or reversely between two power supplies of different voltage or two circuits in response to an external select signal. SOLUTION: In the step-up/down type DC-DC converter (1) transferring power from the low voltage side to the high voltage side or reversely between two power circuits of different voltage in response to an external select signal, a gate control circuit (4) performs zero-cross control through a circuit comprising first and second transistors (Q1, Q2) connected in series and provided with inverse parallel diodes (D1, D2) between the I/O terminal (N2) of a high voltage circuit (2) and the ground (GND), a reactor (L) connected between the joint (N3) of two transistors and the I/O terminal (N1) of a low voltage side circuit (3), a snubber capacitor (C3) connected between the joint (N3) and the ground (GND), a zero-cross detecting circuit (5) for detecting the moment in time when the voltage between the joint (N3) and the ground (GND) becomes zero, and the gate control circuit (4) for controlling switching operation of the first and second transistors. COPYRIGHT: (C)2005,JPO&NCIPI
|
