Load abnormality detection circuit

A load abnormality detection circuit serves to stop the operation of a load when the load is shorted to a VB power supply, or when the load is layer shorted, whereby heat damage of a load control transistor is prevented. A microcomputer provides a drive signal to a base of the transistor thereby to drive the load. A voltage detection circuit detects a voltage level between a collector and an emitter of the transistor and inputs it to the microcomputer. The microcomputer sets first and second thresholds corresponding to the voltage levels of a collector voltage of the transistor when the load is abnormal, and detects when the load is abnormal based on a comparison of the voltage level detected with the thresholds. The presence or absence of abnormality of the load is detected based on at least two comparison results.