Patent ID: 7928708

Claim:
A constant-voltage power circuit comprising: a control voltage output circuit receiving a reference voltage and a divided voltage dividing an output voltage, and outputting a control voltage in accordance with the difference between the reference voltage and the divided voltage; an output circuit receiving the control voltage to generate a stabilized output voltage from a high-potential-side power supply voltage, wherein the output circuit includes an output node to output the stabilized output voltage; a first P-type MOS transistor carrying a current from the output node; a capacitor connected between the output node and a supply node of low-potential-side power supply voltage; and a P-type MOS transistor current control circuit controlling a gate of the first P-type MOS transistor so that a current flowing through the first P-type MOS transistor becomes a constant value, wherein the P-type MOS transistor current control circuit includes: a constant-current source having a first terminal and a second terminal, the first terminal being connected to the supply node of low-potential-side power supply voltage; and at least one second P-type MOS transistor having gate and drain mutually connected, and a current path between source and drain, which is interposed between a supply node of the high-potential-side power supply voltage and the second terminal of the constant-current source, wherein the gate of the first P-type MOS transistor is connected to the other terminal of the constant-current source.