| 摘要 |
PURPOSE:To obtain a power converter with small size and high efficiency while attaining high-speed turn-off, by supplying a positive driving current from a driving circuit power supply at turn-on to a control gate of a semiconductor and a negative driving current from a main circuit at turn-off. CONSTITUTION:A transistor (TR)Q1 turns on with a control circuit 3, a voltage is induced to windings n4, n5 of a base driving rransformer TB and a power TRQM is turned on by being supplied with a positive base current. Thus, the base.emitter of a TRQ2 are back-biased with a voltage drop of a diode D2 and the TRQ2 is turned off and a voltage is remained induced in a winding n3 of a main transformer TM. In interrupting a base current to the TRQ1 from the circuit 3, the Q1 is turned off. Thus, the TRQ2 turns on and a negative base current flows to the TRQM through the Q2 from the winding n3 to rapidly turn on the QM. Since the negative base current is obtained from a main circuit at the QM turned off, a driving power supply has only to supply required power for turning-on of the QM, allowing to attain small size. |
