Parallel transistor protection circuit

摘要

A circuit arrangement for protecting the remainder of a plurality of parallely operated transistors in the event any one of the transistors fails in a shorted condition. An open circuited failure has no adverse effect upon the operating circuit. Each transistor includes a "slow" turn-off diode with respect to the period of the input drive signal, coupled in series between a common input signal-feed point and the base of the transistor to which it is connected. The diodes are poled to block the collector B+ supply potential appearing at the base of the respective shorted transistor, thus preventing the B+ supply potential from being applied to the base of the remaining transistors. Additionally, a respective fusister is connected in series between each emitter and the load circuit line in order to thereafter remove the failed transistor from the circuit and to balance the transistor currents during normal operation.