PURPOSE: To quickly execute a turn-on and to reduce the loss of switching at a turn-on time by providing more winding to a second transformer and connecting a series connection circuit consisting of the winding and a field effect transistor in parallel with a semiconductor switching element.
CONSTITUTION: The series connection circuit consisting of a diode 13, the field effect transistor(FET) 14 and a third winging NC of a current feedback transformer 8 is connected in parallel with a transistor 1. Since the FET 13 has a fast switching speed though its saturation voltage is high, it can send a current instead of the transistor 1 until the transistor 1 is turned off. And at the same time, since the current flows through the winding NC of the current feedback transformer 8 until the transistor 1, at least, becomes the saturated state, positive feedback is given to the base of transistor 1 through the current feedback transformer 8, the diode 9, the winding N3 and a switching element 2, so that the turn-on of the transistor 1 can be accelerated.
KUWATA YUTAKA
KII YASUO
NIPPON TELEGRAPH & TELEPHONE
| JPS60264120A | 1985-12-27 | |||
| JPS61104641U | 1986-07-03 |