Patent ID: 7289783

Claim:
A mixer circuit comprising: a first differential transistor having a gate, a source, and a drain, wherein the source of the first differential transistor is a first input of the mixer circuit; a second differential transistor having a gate, a source, and a drain, wherein the source of the second differential transistor is a second input of the mixer circuit; and a first capacitor coupled between the source of the first differential transistor and the source of the second differential transistor; a first bias transistor having a gate, a source, and a drain, wherein the drain is coupled to the source of the first differential transistor; a second bias transistor having a gate, a source, and a drain, wherein the drain is coupled to the source of the second differential transistor; a first sensing circuit coupled to the source of the first bias transistor; a second sensing circuit coupled to the source of the second bias transistor; a first comparison circuit coupled to the first sensing circuit; and a second comparison circuit coupled to the second sensing circuit, wherein the first comparison circuit receives a feedback signal from the first sensing circuit and a reference voltage, and in accordance therewith, generates a first bias control signal to control the bias at the gate of the first bias transistor, and wherein the second comparison circuit receives a feedback signal from the second sensing circuit and the reference voltage, and in accordance therewith, generates a second bias control signal to control the bias at the gate of the second bias transistor.