CMOS Implementation of Low-Frequency Pattern Generator for Electrochemical Sensing

In this paper, a pattern generator architecture is presented to generate the staircase and square waves for electro-chemical sensing. The proposed system consists of a finite-state machine (FSM) stage to produce a specific counting sequence, a selector block and a pattern generation block to produce such patterns from an external reference clock. The system produces both the staircase and square patterns needed for performing voltammetry in the electrochemical sensing. The proposed pattern generator is designed using a standard CMOS 180 nm technology. The staircase pattern shows a linear behaviour with an uniform step size of ∼76.9 mV varying from 1 V to 2 V. The generated square wave has a a peak-to-peak voltage of ∼153.8 mV and its local average coincides with the same of the staircase pattern in each step enabling an accurate matching of these two patterns. The system consumes an average power of 916 µW at a supply voltage of 2.7 V.