DC-TO-DC CONVERTER, SWITCHING REGULATOR AND LSI SYSTEM PROVIDED THEREWITH

摘要

PROBLEM TO BE SOLVED: To maintain high power conversion efficiency of a switching regulator and further suppress inrush current. SOLUTION: A synchronous rectifying switching regulator is provided with first and second switches SW1 and SW2 placed in series between a power supply Vdd and ground Vss, a switch control unit 1 which controls turning on/off of the switches SW1 and SW2, and a smoothing circuit 4 which smoothes an output node potential Vnd. If a signal Sc1 indicates that the output node potential Vnd is below a first reference potential Vr1, which is used as a reference for detecting the production of an inrush current when the first switch SW1 is on, a control circuit 10 turns the first switch SW1 into an off state. That is, since an inrush current is detected by utilizing voltage drop due to the on-resistance of the first switch SW1, installation of an resistance element for inrush current detection is unnecessary.