Design of a low-power potentiostatic second-order CT delta-sigma ADC for electrochemical sensors

A low-power potentiostatic second-order continuous-time delta-sigma modulator architecture for electrochemical amperometric sensors is presented. The architecture takes advantage of the intrinsic double-layer capacitance of the sensor used as an integrator stage to have a compact and energy efficient conversion of the electrochemical signal. The addition of a second integrator guarantees the real potentiostat operation while introducing new design trade-offs such as stability and resolution. The circuit has been simulated in a standard 0.18 μm CMOS technology. As a proof of concept, a cyclic voltammetry based on real measurements is also presented.