SWITCHING REGULATOR AND LSI SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a switching regulator that achieves high efficiency of power conversion for the wide range of load currents. SOLUTION: Switches SW1, SW2 are provided in series between a power supply Vdd and a power supply Vss. A switch controlling part 10 turns off the switch SW2 forcibly when the switch SW2 is in a on-state, if the electric potential at a node V1 exceeds the electric potential Vss. Specifically, the direction of the current IL which flows in a smoothing circuit 4 is detected with the electric potential of the node V1 so that the current IL is prevented from flowing to the reverse direction eventually to the power supply Vss and the degradation of the power conversion efficiency is prevented. This structure allows intermittent mode operations without providing a resistor inside the smoothing circuit 4. As a result, the power conversion efficiency for a small load current can be improved without increasing DC power loss for a large load current.