Short circuit protected driver stage - has monitoring circuit in front of power transistor for latter blocking at high consumer current, or short circuit

摘要

The drivers stage has a power transistor via which the consumer appliances, such as relays, warning lamps, magnetic valves etc. can be energised. A series resistor limits a short circuit currents. In front of the power transistor (T1) is series connected a monitoring circuit (2), which automatically blocks the power transistor energising at excessively high consumer current, or a short circuit. The series resistor (3) is incorporated in the emitter or source circuit of the power transistor. The energising signal at the transistor control electrode is pref. limited by a Zener diode (6) etc. to a max. value. USE/ADVANTAGE - For car electronic system, with high reliability, low-cost mfr., at negligible lossy power on short circuit.