A novel compact instrumentation amplifier for optimal interfacing of thermoelectric sensors

An original architecture for the design of low-noise, low offset instrumentation amplifiers is described. The amplifier, based on a modified indirect current feedback structure, exploits chopper modulation to reject input offset voltage and low frequency noise. The key features of the proposed topology are: (i) embedding of the chopper modulation scheme into a 2nd order Gm-C low pass filter to obtain intrinsic chopper ripple rejection; (ii) equalization of the input and feedback common mode voltages for improved gain accuracy; (iii) biasing of the input devices in deep subthreshold region, to improve noise vs. power consumption efficiency. The effectiveness of the approach is illustrated by means of accurate electrical simulations.