トランスインピーダンス増幅回路、及び利得可変増幅器

摘要

PROBLEM TO BE SOLVED: To improve linearity of an output signal with respect to an input signal.;SOLUTION: A variable gain amplifier circuit 13 of a transimpedance amplifier circuit generates a pair of output signals Vout1 and Vout2 according to a voltage signal Vin and a reference signal Vref. A differential circuit 23 of the variable gain amplifier 13 includes: a transistor 31 having a base to which the voltage signal Vin is input; a transistor 32 having a base to which the reference signal Vref is input; and a variable resistance circuit 33 having a plurality of FETs 35_1 to 35_N, each source of which is connected to an emitter of a transistor 31 and each drain of which is connected to an emitter of the transistor 32. On/off states of a plurality of FETs are switched by linearity adjustment signals Vctl_1 to Vctl_N, so that a resistance value of the variable resistance circuit 33 increases as an amplitude of the voltage signal Vin increases.;SELECTED DRAWING: Figure 2;COPYRIGHT: (C)2019,JPO&INPIT