Circuit Techniques to Suppress Crosstalk Due to Circuit Nonidealities in Zero-Potential-Biasing Method for Resistive Sensor Matrix

Abstract

Crosstalk between the sensor element to be read and the other sensor elements in the sensor matrix constitutes a critical problem in reading passive matrix resistive sensors. Various zero-potential-biasing readout circuits have been proposed to solve the crosstalk problem, but crosstalk remains due to circuit nonidealities, such as the offset and finite open-loop gain of the amplifiers and the ON-resistance of the switches used in the readout circuit. Therefore, we propose a novel low crosstalk zero-potential-biasing readout circuit that can suppress crosstalk caused by these nonidealities of circuits. The main ideas of the proposed readout circuit to suppress crosstalk are: 1) including the unaddressed sensors and switches into the feedback loop that is formed by the biasing amplifier to remove crosstalk resultant from the finite open-loop gain of the amplifiers and the ON-resistance of the switches and 2) applying the correlated double sampling method to remove crosstalk caused by the offset of the amplifiers. In the measurement of the proposed readout circuit composed of actual commercial amplifiers and switches, the maximum readout error of the proposed readout circuit for an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8\times $ </tex-math></inline-formula> 8 resistor matrix is reduced to lpzrptPlus51.82% from the errors of −81.32% and −88.68% of the previous readout circuits selected for comparison.