Patent ID: 7339432

Claim:
A variable gain amplifier, comprising: an amplifying element for signal amplification, having a first current path and a first control terminal; an amplifying element for gain control at an output side, having a second current path connected to a load at an output side, and a second control terminal; an amplifying element for gain control at a non-output side, having a third current path connected to a load at a non-output side, and a third control terminal; and first and second negative feedback paths, so that an electric current, which corresponds to an input signal input to said first control terminal and amplified by a gain determined by control signals input to said second and third control terminals, will flow to said load at the output side via said second current path, wherein: said amplifying element for signal amplification, said amplifying element for gain control at the output side, and said amplifying element for gain control at the non-output side are connected to one another such that a current flowing in said first current path will dividedly flow to said second and third current paths; said first negative feedback path connects said second current path to said first control terminal, in order to return a feedback signal according to an amount of a current flowing in said load at the output side to said first control terminal; and said second negative feedback path connects said third current path to said first control terminal, in order to return a feedback signal according to an amount of a current flowing in said load at the non-output side to said first control terminal.