Patent ID: 8248112

Claim:
A transconductance amplifier for generating a first output voltage signal and a second output voltage signal proportional to a difference between a first input voltage signal and a second input voltage signal applied thereto from a first and a second output stage, respectively, said transconductance amplifier characterized by comprising: a feedback signal output terminal for outputting common-mode components of the first output voltage signal and second output voltage signal; a feedback signal input terminal; a reference signal input terminal; and feedback signal conveying means for controlling the first output voltage signal or second output voltage signal in accordance with an input signal to said feedback signal input terminal and an input signal to said reference signal input terminal, wherein said feedback signal input terminal, said reference signal input terminal and said feedback signal conveying means are provided in said first and second output stages, and said feedback signal conveying means is connected to each output stage, and said feedback signal conveying means comprises: a current mirror circuit having an output part connected to said output stage; a first transistor of a first conductivity type having a control terminal connected to said feedback signal input terminal; and a second transistor of a second conductivity type having a control terminal connected to said reference signal input terminal for determining a reference current for said current mirror circuit together with said first transistor.