| 摘要 |
PURPOSE:To decrease the idle current and to widen the range of the class A operation by providing a voltage-current conversion circuit applying voltage- current conversion to an input signal to be amplified, a current-current conversion circuit supplying a constant current, an output circuit and a circuit feeding back an output of the output circuit to the voltage current converter negatively. CONSTITUTION:Emitters of an NPN transistor (TR) 1 and a PNP TR 3 are connected in common in the the current-voltage conversion circuit, a signal is inputted from the common emitter, emitters of TRs 2, 4 whose base and collector are connected in common respectively are connected together and a constant current is fed thereto. An amplifier 22 constitutes the voltage-current conversion circuit and a current Ix is outputted to an input signal Vin. The current Ix is divided into currents Ic1, Ic3 in the current-current conversion circuit 1, amplified by current mirror circuits 18, 20 by A-time and outputted after being combined. An output signal Vout is fed back to the input of the amplifier 22 via a feedback circuit 24.
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