Load drive control apparatus having minimized power consumption when functioning in waiting status

摘要

In a load drive control system containing a control apparatus and a drive apparatus which drives a load in accordance with a drive control signal supplied from the control apparatus, a single signal produced from the control apparatus serves both as the drive control signal and as a power supply enabling control signal for the drive apparatus, without the need to provide an internal DC power supply in the drive apparatus. A switching element in the drive apparatus is controlled to apply a supply voltage from a drive power source to circuits in the drive apparatus only while the drive control signal is being supplied from the control apparatus.