Load driving and diagnosis system

摘要

A load driving and diagnosis system controls the feed and block of a load current flowing into an inductor such as a solenoid. The load driving and diagnosis system holds a counter-electromotive force, which is developed when the load current is blocked, at a voltage higher than a supply voltage so that the load current will decay for a short time. When an overcurrent condition is established in the load driving and diagnosis system because of a short circuit to a power supply 101, a malfunction of a circuit or destruction thereof may take place. In addition to a voltage holding means 50 that holds a switching circuit output voltage at a predetermined voltage, a voltage holding means 50 having a different predetermined voltage set therein is included. Moreover, a selection switch 50a that switches the predetermined voltages according to a detected overcurrent condition is included.