Voltage controlled current source and bias generation circuit using such current source

摘要

Current I.sub.P through a transistor 2 linearly decreases according to control voltage V.sub.I in the range from 0 to V.sub.DD -V. sub.TP. Current I.sub.N through a transistor 3 linearly increases according to control voltage V.sub.I in the range from V.sub.TN to V.sub. DD. In a subtraction/inversion circuit 5, constant current I.sub.CONST is introduced, I.sub.P is subtracted therefrom, and &Dgr;I having an inclination in the same direction as I.sub.N is produced. Bias current I. sub.B serially changing in the range of V.sub.I from 0 to V.sub.DD passes through a transistor 7. Accordingly, even if control voltage V.sub.I is smaller than the threshold voltage V.sub.TN of an input transistor, current I.sub.B or voltages V.sub.PP and V.sub.BN which linearly change according to control voltage V.sub.I are output.