US Patent 7719351 Autozeroing current feedback instrumentation amplifier

An embodiment is directed to an instrumentation amplifier. The instrumentation amplifier includes an output stage for generating an output voltage, a low-frequency path coupled with the output stage, and a high-frequency path coupled with the output stage. The high-frequency path dominates the low-frequency path at frequencies above a particular frequency, and the low-frequency path dominates the high-frequency path at frequencies below the particular frequency. The low-frequency path includes an input stage for sensing a differential input and generating an intermediate current based thereon, a feedback stage coupled with the input and output stages, the feedback stage for generating a feedback current based on the output voltage, and an auto-zeroing circuit coupled with the input, feedback, and output stages, the auto-zeroing circuit for generating a nulling current. The nulling current compensates for errors in the intermediate and feedback currents resulting from input offsets in the input and feedback stages.