Patent ID: 7463087

Claim:
A circuit for minimizing a voltage offset between inverting and non-inverting input terminals of an operational amplifier circuit, the circuit comprising: A chopper circuit connected to the inverting and non-inverting input terminals of the operational amplifier circuit, the chopper circuit comprising: An amplifier having differential outputs; a switching circuit for periodically reversing the input terminals to the amplifier and periodically reversing the outputs of the amplifier to provide an output signal comprising an offset adjustment signal to the operational amplifier circuit to adjust the offset of the operational amplifier circuit; Wherein the switching circuit comprises a first switching circuit connecting the input terminals of the operational amplifier circuit to the amplifier and a second switching circuit connecting the output of the amplifier as the offset adjustment signal; Further comprising a clock circuit for providing a clock signal to the switching circuit for periodically operating switches thereof; and A filter circuit connected at the output of the chopper circuit to provide a DC level signal as the offset adjustment signal.