PROBLEM TO BE SOLVED: To make overcurrent protection according to a load compatible with securing of instantaneous current.;SOLUTION: An overcurrent protection circuit has a threshold value generating section for changing over the overcurrent detection threshold Iocp between a first setting value IocpH and a second setting value IocpL(IocpH) according to a threshold control signal, and threshold value control section generating the threshold control signal so as to change over the overcurrent detection threshold Iocp to the second setting value IocpL at a moment in time when a mask period Tmask elapses with the monitoring object current Io remaining above the second setting value IocpL when the overcurrent detection threshold Iocp is the first setting value IocpH. The threshold value generating section includes a function for gradually lowering the overcurrent detection threshold Iocp over a prescribed transition time Ttrans, when changing over the overcurrent detection threshold Iocp from the first setting value IocpH to the second setting value IocpL.;SELECTED DRAWING: Figure 29;COPYRIGHT: (C)2019,JPO&INPIT
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