CONSTANT-CURRENT GENERATING CIRCUIT, CONSTANT-VOLTAGE GENERATING CIRCUIT, CONSTANT-VOLTAGE, AND CONSTANT- CURRENT GENERATING CIRCUIT, AND AMPLIFIER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a constant-voltage generating circuit which is composed of a field effect transistor and can generate a constant voltage without depending upon variation in source voltage, temperature change, and variance of processes. SOLUTION: A current It flows to the n channel MOS field effect transitsro 13 of the constant-voltage generating circuit 10 and a current Ir which is equal to or a constant multiple of the current It flows to a resistance 18. The transistor 13 has its bias so set that it operates in its saturation area. A voltage Va applied across the resistance 18 is determined univocally by the gate-source voltage of the transistor 13. The difference between the threshold voltage Vt of the transistor and the voltage Va applied across the resistance 18 is set to be within a range from 0.1 V to 0.4 V, and thus the current In flowing to the restance 18 becomes constant without depending on temperature change.