Patent ID: 7268624

Claim:
A offset compensation circuit for differential amplifiers having first and second load impedances and first and second differential output signal terminal means and output terminal means comprising, in combination: first and second adjustable current source means coupled to said differential amplifier means for supplying currents through said first and second load impedances, respectively, said first and second adjustable current source means including control input means for determining the amount of current to be supplied; polarity determining means coupled to said first and second output terminal means for supplying an output signal indicative of polarity of an output signal across said differential output signal terminal means; offset calibration means responsive to the output signal from said polarity determining means for supplying control signals to the control input means of said first and second adjustable current source means; and means in said offset calibration means for varying said control signals until said output signal from the polarity determining means indicates a change in polarity.