Feedback control reducing signal distortion produced by differential

Abstract

A low distortion differential amplifier circuit includes a primary differential circuit stage and a secondary differential circuit stage. The primary differential circuit stage includes first and second transistors each having a first current source coupled to the emitters of the first and second transistors. A first load device is coupled to the collector of the second transistor. The secondary differential circuit stage includes third and fourth transistors. A second current source is coupled to the emitters of the third and fourth transistors. The bases of the third and fourth transistors are coupled to the collectors of the first and second transistors, respectively. A second load device is coupled to the collector of the fourth transistor. A fifth transistor has its emitter and collector coupled to a supply voltage conductor and the base of the third transistor, respectively. The base of the fifth transistor is coupled to the collector of the fourth transistor, whereby the secondary differential circuit stage maintains the second current-carrying electrodes of the first and second transistors at equal voltages to reduce distortion due to differences in voltages between the control electrode and second current-carrying electrode of the first and second transistors.