| 摘要 |
PROBLEM TO BE SOLVED: To provide a step-up and step-down chopper circuit that can reduce hard switching loss and make the switching frequency high. SOLUTION: A series circuit composed of a first transistor 4 and a first diode 6 is connected to a DC power supply 1 in parallel therewith, and a series circuit, composed of a capacitor 13, a second diode 12 and a second transistor 8, is connected to an output load side in parallel therewith. A first reactor 7 is connected to the connection point of the first transistor 4 and the first diode 6, and to the connecting point of the second diode 12 and the second transistor 8. Effective resonance capacitors 5, 9 are connected in parallel between the collector of the first transistor 4 and the emitter of the second transistor 8, and the collector currents of the transistors are made to flow to the resonance capacitors 5, 9, when the first and the second transistors 4, 8 are turned off, to make the resonance capacitors perform soft switchings. When charges accumulated in the resonance capacitor 5 are discharged, and the charge of the resonance capacitor 5 becomes zero, the first transistor 4 is tuned on, to make the resonance capacitor perform zero-voltage switching. COPYRIGHT: (C)2005,JPO&NCIPI
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