Abstract
A wide input range, compliant with electrochemical amperometric sensors interface circuit is proposed in this paper. The interface circuit consists of a potentiostat which is fabricated on PCB board and an interface ASIC which is realized in a single chip. The ASIC employs current integrator (CI) and transimpedance amplifier (TIA) to deal with the input current in the order of nA and µA separately, achieving the advantage of wide input range and high resolution. An incremental sigma-delta ADC is employed to digitize the transferring signal to achieve the feature of one-to-one mapping between input and output. The ASIC is fabricated in 0.18 µm 1P5M mixed-signal CMOS process, has a dynamic range of 120 dB, and consumes 4.2 mA.
