| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: as the result of transition from intermittent control mode to continuous control mode, undershoot or the like is produced in output and this impairs stability, response, and low power consumption. SOLUTION: A switching power supply includes: an inductor L1 and multiple switch elements Q1, Q2, Q4; a switch control circuit 50 that generates controlled variable signals SA, SB for output voltage Vout to control the switch elements and can be switched between intermittent control (PFM) and continuous control (PWM) based on a mode signal; a capacitor CC connected to a generation node ND of the controlled variable signal SA when in the PWM mode; a voltage generation circuit 30 that generates an ideal voltage SE corresponding to the result of detection of a level difference between input voltage Vin or output voltage Vout and a target value; and a capacitor connection switch SW that changes the connection and disconnection of the capacitor CC to and from the node ND based on a mode signal and presets an ideal voltage SE from the voltage generation circuit 30 on the capacitor CC when the capacitor is disconnected. COPYRIGHT: (C)2008,JPO&INPIT
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