Integrator and active filter including integrator with simple phase compensation

摘要

In an integrator circuit having a wide linearity range, there are provided: a first emitter-coupled transistor pair having two bipolar transistors, emitter areas of the transistors being substantially equal to each other; a second emitter-coupled transistor pair having two bipolar transistors, emitter areas of said transistors being substantially equal to each other; first and second input terminals for receiving an input voltage respectively; a first output terminal to which a first collector of the first emitter-coupled pair and also a first collector of the second emitter-coupled transistor pair of commonly connected; a second output terminal to which a second collector of the first emitter-coupled transistor pair and also a second collector of the second emitter-coupled transistor pair are commonly connected; first DC- voltage applying means connected to the first input terminal, for applying a first offset DC (direct current) voltage having a predetermined level between a first base electrode of the first emitter- coupled transistor pair and a first base electrode of the second emitter- coupled transistor pair; second DC-voltage applying means connected to the second input terminal, for applying a second offset DC voltage having the same level but an opposite polarity to that of the first offset DC voltage between a second base electrode of the first emitter-coupled transistor pair and a second base electrode of the second emitter-coupled transistor pair; and, capacitance means connected between the first and second output terminals.