| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a switching power supply device that operates with stability even in a region in which an ON width of a switching element is narrow, which is caused by a high input voltage and the like. <P>SOLUTION: A switching power supply device converts a direct-current voltage inputted by a switching operation of a switching element 2 into a predetermined voltage, and supplies the converted voltage to a load 14. The switching power supply device has: a current mode controller that on-off controls the switching element 2 based on a result of comparison between a voltage value of an error amplification signal, which depends on a difference between an output voltage value supplied to the load 14 and a predetermined reference voltage value, and a voltage value of a current detection signal, which depends on a current value flowing in the switching element 2; a voltage mode control circuit 16 that on-off controls the switching element 2 based on a result of comparison between the voltage value of the error amplification signal and a voltage value of a ramp signal having a predetermined frequency; a control mode selection part that selects one of the current mode controller and the voltage mode control circuit 16 to on-off control the switching element 2; and a phase compensation part that adjusts a phase compensation amount so that the phase compensation amount depends on a selection result by the control mode selection part. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
