| 摘要 |
PURPOSE:To attain normal operation even when a potential at an output terminal is lower than the ground potential by providing a diode for preventing reverse current between a collector of a stored carrier extraction transistor(TR) and a base of an output TR. CONSTITUTION:In conducting a switch 9 in the timing when a switch 11 is interrupted to quicken the switching speed, the potential at an output terminal 4 is lowered than the ground potential by a forward voltage of a diode 7 and even when the forward voltage gets higher, a diode 13 is used as a reverse flow preventing diode. When the voltage exceeds the reverse dielectric voltage of the diode 13, so long as the voltage at the output terminal 3 is not lower than the ground potential, the PN junction between the base and collector of an NPN TR 8 is in the forward polarity and an NPN TR 3 is not conductive. Thus, the drive efficiency in using the titled circuit as a PWM(Pulse Width Modulation) drive circuit is improved. |
