| 摘要 |
PURPOSE:To switch a zero current without depending upon a frequency of a resonance circuit by providing the resonance circuit and an auxiliary switching element at a main switching element and operating a resonance operation by the auxiliary switching element. CONSTITUTION:When a transistor 4 of a main switching element is turned ON, charge stored in a resonance capacitor 5 is reversely charged in the capacitor 5, and a resonance operation is interrupted in a state that the charge is maintained. Then, when the transistor 4 is tuned OFF, a transistor 10 of an auxiliary switching element is previously tuned ON. A series circuit is reversely biased by the reversely charged capacitor 5, and the resonance operation is restarted. Since no current flows to the transistor 4 while a resonance current flows to a diode 11, a loss of a zero current switching can be reduced by turning OFF the transistor 4 during this period. A switching frequency can be continuously varied without depending upon the frequency of a resonance circuit by the operation of the transistor 10. |
