| 摘要 |
PURPOSE:To reduce a switching loss due to the charging and discharge operation of the parasitic capacity of a switching transistor and of the input capacity of a piezoelectric transformer by a method wherein a circuit which supplies a charging current to the switching transistor and to the piezoelectric transformer is installed, in parallel with the piezoelectric transformer, across the switching transformer and the piezoelectric transformer. CONSTITUTION:Transistors 4, 5 are driven alternately by signals of oscillators 2, 3, and an input DC voltage from a DC power supply 1 is converted into an AC voltage. At this time, in one cycle during which the transistors 4, 5 are switched, parasilic capacity C1, C2 of a piezoelectric transistor 10 and of the transistors 4, 5 are charged by a DC current flowing in a coil 8 in a dead- time period in which both transistors are set to an OFF state. Thereby, a zero- volt switching operation can be performed, and a switching loss due to a charging and discharge operation can be reduced. |
