Patent ID: 7521997

Claim:
A low-power variable gain amplifier comprising: a load block through which first and second load currents flow from a first source voltage; a first differential input signal source including a terminal connected to a second source voltage and the other terminal connected to a variable gain amplifying block and sinking currents corresponding to a value of a first differential input current signal; a second differential input signal source including a terminal connected to the second source voltage and the other terminal connected to the variable gain amplifying block and sinking currents corresponding to a value of a second differential input current signal; a variable gain amplifying block sinking first and second differential output current signals that are branch currents of the first and second load currents, respectively, and first and second destructive-compensation current signals, in response to first and second gain control signals and the first and second differential input current signals; and a DC (direct-current) bias stabilizer processing the first and second destructive-compensation current signals and first and second bias currents that are branch currents of the first and second load currents, respectively, to enable the first and second load currents to include fixed DC current components, wherein the currents sunk to the first and second differential input signal sources include DC current components and AC current components, the DC current components of the first and second differential input signal sources have the same value, and the AC current components thereof have a phase difference of 180°.