A Multifunction Telecommunications Break Switch

A multifunction telecommunications circuit has been developed in a dielectric isolated technology (BCDMOS - Bipolar, CMOS, DMOS) that withstands 550 volt faults across the switching element. The circuit provides the channel break, hook status and the electronic inductor functions. In addition it has its own power conditioner and thermal shutdown circuit. The IC is designed to work in a floating linefeed environment but the input switch logic as well as the supervision output signal are translated to the 5 volt to ground level. An on chip power rail is included to drive the switching elements from a low impedance source. Protection is provided against excessive current levels due to fault conditions with automatic recovery after the fault is removed.