| 摘要 |
PROBLEM TO BE SOLVED: To enhance the total efficiency by controlling a first switching element to be turned off at the time of abnormal load by turning a third switching element on, thereby lessening the stress applied to the switching element at the time of the abnormal load. SOLUTION: When an abnormality detection circuit 2 detects abnormality of a load Z1, a control circuit 3 stops driving a second switching element Q2 and turns on a third switching element Q3 at the same time. Consequently, a diode D4 is turned on. Since the gate terminal voltage of a first switching element Q1 goes to substantially 0V through a diode D5, the first switching element Q1 can be turned off, along with the second switching element Q2 when the abnormality detection circuit 2 detects an abnormality of the load Z1. Consequently, the stress applied to the first switching element Q1 can be lessened, when the load Z1 is abnormal. |
