| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit capable of suppressing an increase in a circuit area and relaxing a rush current when an output voltage rises.SOLUTION: A power supply circuit comprises: a step-down circuit that includes an output transistor connected between an input terminal for an input voltage and an output terminal for an output voltage and that controls the output voltage by controlling an on resistance of the output transistor; and a voltage control circuit that controls a voltage applied to a back gate of the output transistor, the voltage control circuit applying the voltage higher than a source voltage to the back gate of the output transistor when the output voltage of the step-down circuit is lower than a reference voltage and applying the same voltage as the source voltage to the back gate of the output transistor when the output voltage of the step-down circuit is higher than the reference voltage, thereby exerting a control to increase the on resistance of the output transistor and suppressing a rush current when the output voltage rises.SELECTED DRAWING: Figure 2 |
