Loss reducing device for HV switching transistor stages - imposes positive base current pulse via saturation choke secondary and series connection of diode resistor and inductance

摘要

The protected switching transistor stages are intended for very high clock pulse frequency. During switching of the h.v. transistor stage an additional positive base current pulse is imposed to this stage, via a secondary of a di/dt limiting saturation choke and a tuning series circuit, consisting of a diode, an ohmic resistor, and an inductance. The starting surge is provided by a capacitor, supplying a positive base current from the driver stage, is reset over a diode from the di/dt limiting circuit, when the h.v. switching transistor stage has been disconnected. This circuit arrangement obviates the drawbacks of the conventional systems using RC-elements for generation of dynamic base current peaks.