Patent ID: 7609046

Claim:
A constant voltage circuit for outputting a constant voltage from an output terminal thereof, comprising: an output voltage control circuit for receiving a control signal and controlling a voltage of the output terminal in accordance with the control signal; a temperature characteristic generating circuit for generating the control signal; and an inverse temperature characteristic generating circuit for decreasing the voltage of the output terminal by a predetermined voltage and supplying the resultant voltage to the temperature characteristic generating circuit, wherein the temperature characteristic generating circuit includes: a first and a second diode property element having a first terminal and a second terminal, wherein a forward current flows from the first terminal to the second terminal, and the second terminal is grounded; a first resistance provided between a voltage input end via which the voltage supplied from the inverse temperature characteristic generating circuit is input thereto, and the first terminal of the first diode property element; a second and a third resistance provided the voltage input end and the first terminal of the second diode property element, wherein the second and third resistances are connected in series; and a differential amplification circuit for receiving a first terminal voltage between the second and third resistances, and a second terminal voltage of the first terminal of the first diode property element, and outputting the control signal, wherein the temperature characteristic generating circuit has predetermined temperature characteristic with respect to the supplied voltage under conditions such that the first and second terminal voltages are equal to each other, and the inverse temperature characteristic generating circuit has inverse temperature characteristic that cancel the predetermined temperature characteristic possessed by the temperature characteristic generating circuit with respect to the predetermined voltage by which the voltage of the output terminal is decreased.