Integrator and active filter including integrator with simple phase compensation

摘要

In an integrator circuit (100) having a wide linearity range, there are provided: a first emitter-coupled transistor pair (10) having two bipolar transistors (Q₃: Q₄), emitter areas of the transistors (Q₃: Q₄) being substantially equal to each other; a second emitter-coupled transistor pair (20) having two bipolar transistors (Q₅: Q₆), emitter areas of said transistors (Q₅: Q₆) being substantially equal to each other; first and second input terminals (8: 9) for receiving an input voltage (VIN) respectively; a first output terminal (OUT1) to which a first collector (1) of the first emitter-coupled pair (10) and also a first collector (2) of the second emitter-coupled transistor pair (20) are commonly connected; a second output terminal (OUT2) to which a second collector (3) of the first emitter-coupled transistor pair (10) and also a second collector (4) of the second emitter-coupled transistor pair (20) are commonly connected; first DC-voltage applying means (16: 17) connected to the first input terminal (8), for applying a first offset DC (direct current) voltage having a predetermined level between a first base electrode (11) of the first emitter-coupled transistor pair (10) and a first base electrode (12) of the second emitter-coupled transistor pair (20); second DC-voltage applying means (18: 19) connected to the second input terminal (9), 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 (14) of the first emitter-coupled transistor pair (10) and a second base electrode (13) of the second emitter-coupled transistor pair (20); and, capacitance means (7) connected between the first and second output terminals (OUT₁: OUT₂).