| 摘要 |
PROBLEM TO BE SOLVED: To detect an overcurrent caused by the short circuit of a load and maintain the reliability of an overcurrent detection circuit which detects the overcurrent of a load current by the feedback of the potential of a sensing output to the potential of a load driving output, even if the short circuit of the load occurs. SOLUTION: An overcurrent detection circuit 10 has a current detection circuit 11, a control circuit 12 and a reference voltage generating unit 13. The driving output Vod of a load driving transistor TRd is inputted to the base of the input transistor Q2 of the current detection circuit 11. The sensing output Vos of a sensing transistor Trs is inputted to the base of the transistor Q3 of the current detection circuit 11. The feedback operation is practiced so as to have both the output voltages Vod and Vos equal to each other. A reference voltage VREF generated by a reference voltage generating unit 13 is inputted to the base of an input transistor Q1. If the driving output Vod is lower than the reference voltage VREF, the feedback is practiced so as to have the sensing output Vos equal to the reference voltage VREF, and the abnormal current of a load 50 is detected in accordance with the sensing current Is at that time. |
