摘要 |
<p>In a multiplex system for automotive vehicles, battery (+V) current is supplied to a load (70) connected to a non-intelligent slave unit (20) via a power switch (TR) in the slave controlled by a capacitor (CT) which is charged or discharged in an assigned time slot by high or low drive voltage applied on a low current signal line (42) from a remote intelligent unit (10). If the load (70) goes short-circuit then a thyristor (TH) adjacent the power switch (TR) turns on to turn off the power switch (TR) and provide a discharge path for the capacitor (CT) via the load (70), this discharged condition being detected at the remote intelligent unit during an assigned load driving time slot. Thus a dedicated extra channel (time slot) is not required at the slave unit for short-circuit testing of the load.</p> |