Patent ID: 7605576
Filing Date: 2009-10-20
Classification: H02M,Y02B

Abstract:
1. A switching power supply device, comprising: an input terminal and an output terminal; an inductor arranged between the input terminal and output terminal; a plurality of switch elements connected, adapted and configured for switching a power input path to the inductor and a power output path from the inductor; a switch control circuit connected, adapted and configured to have a control level signal responsive to a difference between an output voltage converted from an input voltage applied to the input terminal and an output from the output terminal and a prescribed target value; the switch control circuit connected, adapted and configured to control the output voltage to approach the target value based on the control level signal by turning on or off the plurality of switch elements; and further connected, adapted and configured to switch between an intermittent control mode and a continuous control mode based on an input mode signal; a capacitor connected to a voltage generation node for the control level signal in the switch control circuit during the continuous control mode; a voltage generating circuit that detects the level difference of the input voltage or output voltage with respect to the target value and generates an ideal voltage corresponding to the detection result; and a capacitor-connecting switch connected, adapted and configured to connect and disconnect the capacitor to and from a voltage generation node for the control level signal based on the mode signal, to connect the capacitor to the output of the voltage generating circuit during the disconnection, and to set the ideal voltage generated at the output for the next connection and preset it for the capacitor.