Relay switching control for protecting against HV transients - has power limiting diode and controlled period of switching using monitored relay condition using microcomputer control unit

摘要

A microcomputer based controller (1) operates a relay using an output coupled via a driver (2) connected to the relay coil (3a). The coil and contacts (3b) connect to the battery (6) and the contacts complete the circuit connection to a low resistance load (5). The state of the load circuit is monitored by a connection made to the microcomputer. The relay driver has a connection to ground via a power limiting diode (4). During normal condition operation of the relay, the diode has no effect. When a high voltage transient occurs the diode responds to provide protection and the monitoring line input ensures that switching is controlled for a specific period. USE/ADVANTAGE - For vehicle on-board voltage networks. Protects control circuit elements against transient overload.