| 摘要 |
PURPOSE:To eliminate an abnormal oscillation by controlling an overdrive of the base current of a switching transistor synchronously with a pulsating voltage by a synchronizing transistor. CONSTITUTION:A smoothing condenser C1 is connected to the output terminal of a rectifier DB2 to smooth a base current, a synchronizing transistor T3 is connected between the condenser C1 and base resistors R1, R2, a resistor R3 is connected to the base to connect to the output side of a choke coil L1. The base current supplying waveforms of switching transistors Tr1, Tr2 decrease in the base current of a transistor Tr3 near the valley point of the pulsating voltage of the input voltage waveform of as oscillating transformer OT, and the VCE voltage of the transistor Tr3 rises. Accordingly, the overdrive of the base currents of the transistors Tr1, Tr2 near the valley point can be eliminated. |
