Constant current generation circuit, constant voltage generation circuit, constant voltage/constant current generation circuit, and amplification circuit

摘要

A current flows through an n-channel MOS field effect transistor in a constant current generation circuit, and a current which is equal to or a constant multiple of the current flows through a resistor. A bias is set such that the transistor operates in a saturation region. A voltage applied across both ends of a resistor is uniquely determined by a gate-source voltage of the transistor. The difference between a threshold voltage of the transistor and a voltage applied across both ends of the resistor is set within a range of 0.1 volts to 0.4 volts, so that the current flowing through the resistor is made constant without depending on the temperature change.