| 摘要 |
PROBLEM TO BE SOLVED: To achieve high efficiency at the time of silent operation.SOLUTION: A power supply control IC 10 comprises: constant on-time switching control circuits (12-18) for performing control of turning ON/OFF of an output transistor N1 according to a comparison result (comparison signal S1) between a feedback voltage Vfb and a reference voltage Vref to generate an output voltage Vout from an input voltage Vin by driving a coil L1; and a noise-reduction circuit 19 for forcibly turning on the output transistor N1 in disregard of the comparison signal S1 when a predetermined threshold time period has been elapsed after ON timing of the output transistor N1 arrives and without arrival of the next ON timing according to the comparison signal S1.SELECTED DRAWING: Figure 15 |
