Current-mode instrumentation amplifier

A current-mode instrumentation amplifier (IA) includes first and second buffer amplifiers which receive a differential voltage (VINP-VINN) and provide output voltages at respective output nodes; a resistance R 1 is connected between the nodes and conducts a current IR1 that varies with VINP-VINN. In one embodiment, each amplifier includes a transistor connected in series with R 1 which conducts current IR1; these currents are coupled to the input and output terminals of a current mirror, preferably via respective virtual ground nodes such that the IA requires only one current mirror, to produce the IA's output voltage. To minimize DC mismatch errors, the IA is chopper-stabilized, with the buffer amplifiers and signal current paths chopped using a two-phase chopping cycle.