CURRENT LIMITING CIRCUIT AND SWITCHING REGULATOR EQUIPPED WITH OVERCURRENT PROTECTIVE FUNCTION

摘要

PROBLEM TO BE SOLVED: To provide a circuit by which a current flowing via an inductor can be limited to a definite upper-limit value. SOLUTION: An input voltage to this switching regulator is given to a switch M1. The inductor L is installed across the switch M2 and an output terminal. A sense resistance Rs is connected in series with the inductor L in order to detect an inductor current. A control circuit 101 generates a control signal which is to be given to the switch M1 on the basis of an output voltage and on the basis of the inductor current. A variable offset voltage source 1 generates an overcurrent detecting set value when an offset voltage which is proportional to the difference between the input voltage and the output voltage is given to an OCL value. A comparator 102 generates a reset signal when the inductor current exceeds the overcurrent detecting set value. When the control circuit 101 receives the reset signal, it turns off the switch M1 forcibly.