Semiconductor circuit.

摘要

A constant voltage circuit according to this invention comprises first means (1) attenuating or dividing fluctuating voltage and an amplifying FET (Q2), to the gate of which the output attenuated or divided by the first means (1) is applied and whose drain is connected with the fluctuating voltage through load means (2). The attenuation ratio or division ratio of the first means (1), the mutual conductance of the amplifying FET (Q2) and the impedance of the load means (2) are so set that the voltage drop across the load means (2) cancels the fluctuating amount of the fluctuating voltage. Consequently an output voltage, which is maintained substantially constant, is obtained at the drain of the amplifying FET (Q2), independently of fluctuations in the fluctuating voltage, and thus a constant voltage circuit can be obtained. A constant current circuit according to this invention utilizes the constant voltage circuit described above. The output voltage of the constant voltage circuit is supplied to the gate of the constant current FET (Q31 - Q3n) Consequently a current, which is maintained substantially constant, flows through the drain-source path of this constant current FET (Q31-Q3n) and thus a constant current circuit can be obtained.