| 摘要 |
PROBLEM TO BE SOLVED: To provide a current-mode-controlled switching power supply device which allows for current feedback even when the ratio of the output voltage to the input voltage is small, without relying upon the input voltage and output voltage.SOLUTION: A switching power supply device 101 includes an upper MOS transistor Q1 (first switch), a lower MOS transistor Q2 (second switch), a current detection circuit 4 for detecting a current flowing through the second switch, and a control unit for controlling the first and second switches depending on a current detected by the current detection circuit 4. The control unit includes a storage unit for storing information of a current detected by the current detection circuit 4 in a predetermined period when the first switch is turned off, a reflection unit for reflecting the information of the current stored by the storage unit on the offset voltage of a slope voltage, and an inclination setting unit for setting the inclination of the slope of the slope voltage to a constant value, and controls the first and second switches depending on the slope voltage.SELECTED DRAWING: Figure 1 |
