| 摘要 |
PROBLEM TO BE SOLVED: To prevent a switching current from exceeding an overcurrent detection level because of the delay of an overcurrent protective operation when a switching element is actually turned off, in a chopper regulator in which the overcurrent protective operation is performed, by making an overcurrent protective circuit turn off the switching element when a switching current detected by a switching current detecting circuit reaches the overcurrent detection level set by a reference voltage circuit. SOLUTION: A switching current inclination detecting circuit 43 detects an inclination of a switching current. The larger the inclination, the lower the overcurrent detection level set by an overcurrent detection level adjusting circuit 44. Thus, the switching current can always be made constant at the point when the switching element is actually turned off, a burden to a device itself can be reduced by allowing a degree of freedom in selecting for peripheral circuit components, and easiness in designing and reliability can be improved.
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