Differential amplifying circuit

Abstract

First and second input signals are supplied to the bases of first and second input transistors, respectively, and the first and second input transistors output currents in accordance with the first and second input signals, respectively. A resistor provided between the emitter of the first input transistor and the emitter of the second input. transistor generates the differential voltage of the first input signal and the second input signal. First and second constant-current sources supply currents to the collectors of the first and second input transistors, respectively. The collectors of first and second control transistors are connected to the emitters of the first and second input transistors, respectively, and the base voltages of the first and second control transistors are controlled in accordance with the emitter currents of the first and second input transistors, respectively. The bases of first and second output transistors are connected to the bases of the first and second control transistors, respectively, and the first and second output transistors control their collector currents in accordance with the base voltages of the first and second control transistors, respectively.