| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress an increased number of terminals by using an overcurrent detection input terminal as a common terminal, enabling the overcurrent detection input terminal for other independent use than original overcurrent detection.SOLUTION: A current flowing in a power transistor MP1 is converted into a voltage V1 by a resistor Rs, so as to be input to an overcurrent detection circuit 18 from an overcurrent detection input terminal 12. An overcurrent detection function to perform overcurrent protection processing is provided when the overcurrent detection circuit 18 detects the occurrence of an overcurrent. A resistor Rf is connected between the overcurrent detection input terminal 12 and one end of the resistor Rs. When the power transistor MP1 is off, a bias current Ib is made to flow into the resistor Rf to generate the voltage V1 at the overcurrent detection input terminal 12, and the comparison result of the generated voltage V1 with reference voltages VrefA, VrefB is retained. According to the comparison result, a control switchover circuit 25 switches modification, activation or deactivation of a function related to switching power supply control.</p> |
