Constant voltage constant current generation circuit

摘要

A constant voltage constant current generation circuit includes a first transistor, a first resistor connected between the first terminal and a second potential, a first diode connected in series with the first resistor, and a first operational amplifier which outputs a first control signal to a control terminal of the first transistor. The constant voltage constant current generation circuit includes a current output circuit which outputs a constant current from a current output terminal according to the first control signal, a second transistor through which a second current flows, the second current obtained by mirroring a first current flowing through the first transistor, a second resistor connected between the voltage output terminal and the second potential. The constant voltage constant current generation circuit includes a current source which outputs a current to the voltage output terminal, and which has negative current characteristics with respect to a temperature change, and a reference voltage output circuit which outputs the reference voltage from a reference voltage terminal.

主权项

1. A constant voltage constant current generation circuit comprising: a first transistor connected at a first end thereof to a first potential and connected at a second end thereof to a first terminal; a first resistor connected between the first terminal and a second potential; a first diode connected in series with the first resistor between the first terminal and the second potential; a first operational amplifier which is supplied with a voltage at the first terminal and a reference voltage, and which outputs a first control signal to a control terminal of the first transistor; a current output circuit which is connected between the first potential and the second potential, and which outputs a constant current from a current output terminal according to the first control signal; a second transistor which is connected between a voltage output terminal for outputting a constant voltage and the first potential, which is supplied at a control terminal thereof with the first control signal, and through which a second current flows, the second current obtained by minoring a first current flowing through the first transistor; a second resistor connected between the voltage output terminal and the second potential; a current source which is connected between the first potential and the voltage output terminal, which outputs a current to the voltage output terminal, and which has negative current characteristics with respect to a temperature change; and a reference voltage output circuit which outputs the reference voltage from a reference voltage terminal, wherein the reference voltage output circuit comprises: a third transistor which is connected at a first end thereof to the first potential, and through which a third current flows; a third resistor connected between a second end of the third transistor and the second potential; a fourth transistor which is connected at a first end thereof to the first potential, which is connected at a second end thereof to the reference voltage terminal, and through which a fourth current equivalent to the third current flows; a second diode which is connected at a first end thereof to the second end of the fourth transistor, and which is connected at a second end thereof to the second potential; and a second operational amplifier which is supplied with a voltage between the second end of the third transistor and the third resistor and a voltage between the second end of the fourth transistor and the second diode, and which outputs a second control signal to a control terminal of the third transistor and a control terminal of the fourth transistor, the first diode being higher than the second diode in capability of letting a current flow with respect to same voltage drop.