| 摘要 |
PURPOSE:To increase the du/dt dielectric strength of a power transistor (TR) and to prevent a reverse TR operation by applying a reverse potential between the base and emitter of the power TR. CONSTITUTION:An ON-circuit is constituted to flow an ON-current and the power TR12 is turned on and held on. Then, an OFF-circuit is composed of a capacitor 8, a TR7, the emitter and base of the TR12, and a capacitor 9 to flow an OFF-current, and the TR12 is turned on. At this point of time, the capacity of the capacitor 9 is far larger than that of a capacitor 8, so the capacitor 8 is discharged completely, but the capacitor 9 is hardly discharged. Then, the reverse bias circuit consisting of the capacitor 9, resistance 10, TR7, and the base and emitter of the TR12 applies the discharging potential of the capacitor 9 between the emitter and base of the TR12 as a reverse bias voltage. |
