Patent ID: 7602249

Claim:
An amplifier circuit comprising: a first amplifier stage comprising a differential pair, the differential pair comprising a first input transistor controlled by a first input signal and a second input transistor controlled by a second input signal; means for measuring a common mode output voltage of the amplifier circuit based on first and second output signals of the amplifier circuit; a first electronic component comprising a first gate, a second gate, a source, and a drain; a second electronic component comprising a first gate, a second gate, a source, and a drain, the second electronic component configured to bias the first amplifier stage; and wherein: the first gate of the first electronic component is coupled to the first gate of the second electronic component and the drain of the first electronic component to form a current mirror; a reference voltage is coupled to one of the second gate of the first electronic component or the second gate of the second electronic component; the common mode output voltage is coupled to the other of the second gate of the first electronic component or the second gate of the second electronic component that is not coupled to the reference voltage; and whereby a reference current flows through the first electronic component.