An amperometric sensor readout circuit for multiple electrochemical sensor cells

In this paper, a 3-electrode amperometric sensor readout circuit that can be used for multiple electrochemical sensor cells is presented. The circuit consists of a wide current range amperometric sensor readout circuit that utilizes a PMOS source at the input thereby providing low input impedance. The circuit can be used for different electrochemical cells via PMOS pass elements that enable their corresponding working electrodes. A programmable voltage generator circuit has also been designed to generate the redox potential of the analyte (calcium oxalate and uric acid). Simulations have been carried out using HSPICE G2012.06. An equivalent on-board module has also been designed using discrete components. The results of both the circuit pre-layout simulation and actual implementation are presented. The amperometric sensor readout circuit has been implemented using TSMC 0.35um 2P4M Mixed Mode Process.