Abstract:
High-speed circuit protection from high-current pulses is obtained by providing a transmission line loop that includes a light emitter and photodetector at opposite ends of the loop. The optical link between the emitter and photodetector is much shorter than the electrical path of the loop. A spurious highcurrent pulse excites the emitter, causing the photodetector to arm a dissipating or shunting element before the pulse traverses the loop. Thus, circuit protection from very high-rise time pulses can be provided by relatively low-response time elements. Other embodiments are also described.