| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the power consumption of a constant-voltage power-supply circuit and to stabilize the operation of the constant-voltage power-supply circuit. <P>SOLUTION: A constant-voltage power-supply circuit 10 includes a bias generating section 11, a reference-voltage generating section 13, a constant-voltage generating section 14, a bias switch 16, and a constant-voltage control section 15. The bias generating section 11 generates a bias voltage. The reference-voltage generating section 13 is connected to the bias generating section 11 and generates a reference voltage on the basis of the bias voltage. The constant-voltage generating section 14 generates a constant voltage on the basis of the bias voltage and the reference voltage. The bias switch 16 changes a bias of the constant-voltage generating section 14. The constant-voltage control section 15 obtains a detection voltage according to a constant voltage or a power-supply voltage and generates a constant-voltage control signal setting the operating state of the constant-voltage generating section 14 to an enable state or a disable state according to a difference between the reference voltage and the detection voltage and a switch control signal controlling the bias switch 16. The bias switch 16 changes the bias of the constant-voltage generating section 14 by the switch control signal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
