New Approaches for Increasing Accuracy in Readout of Resistive Sensor Arrays

Abstract

One of the most efficient ways to connect a resistive sensor array is using columns and rows in a 2-D structure. The main problem in this implementation is crosstalk appearing due to non-idealities in the readout circuits. Crosstalk causes measurement errors which restrict the usable range in array size or resistive sensors values. This paper analyses the way in which these factors affect accuracy, setting out a new approach to eliminate or reduce their influence based on just an additional operational amplifier and some calibration resistors without a significant increase in readout time. The first method involves introducing an additional column in order to eliminate the combined effect of the output resistance buffers for row selection, offset voltages and bias current of the operational amplifier. In the second method, a row of resistors is added in order to reduce the effect of finite gains. Theoretical analysis has been performed and validated by simulation. Results show that an improvement in accuracy compared with other proposals in the literature is possible.