Mixing Integrator for Compact Electrochemical Impedance Spectroscopy

With the rapid development in the miniaturization and monolithic integration of electrochemical sensors with integrated microchips on semiconductor technology, the power and area efficiency of the instrumentation circuits have become an emerging interest. Electrochemical Impedance Spectroscopy (EIS) is an analytical technique widely used in electrochemistry to investigate the properties of materials and electrode reactions. A conventional frequency-response analyzer (FRA) is a powerful EIS measurement instrument composed of amplification, mixing, and low-pass filtering blocks. This paper presents a resetting timing scheme in an integrating amplifier with capacitive feedback for combining three functions into one circuit. The proposed method benefits from lower power consumption and reduced silicon area occupation, as well as eases the design complexity. The theoretical principle of timing selection is expressed in mathematical equations and verified by the circuit simulations.