A CMOS Current-Mode Hyperbolic-Sine-Based Three-Electrode Sensor Interfacing and Amplification Circuit

This paper details the design and operation of a two-stage current-input current-output topology suitable for three-electrode amperometric sensor measurements. The first stage is an interface providing current-follower block, whereas the second stage is a novel hyperbolic-sine-based current amplification stage. The linear amplification stage bases its operation upon the compressive sinh^-1 conversion of the interfaced current to an intermediate auxiliary voltage and the subsequent sinh expansion of the same voltage. The proposed topology has been simulated using the parameters of the commercially available 0.8 mum AMS CMOS process. A variety of confirming cadence design framework simulation results for current gain values ranging from 10 to 1000 are provided. The proposed interfacing/amplification architecture operates in weak-inversion consuming 0.11-5.5 muWs and occupies an area of 900 x 500 mum².