A new discrete circuit for readout of resistive sensor arrays

in this paper, we present a method that simplifies the interconnect complexity of N x M resistive sensor arrays from N x M to N + M. In this method, we propose to use two sets of interconnection lines in row-column fashion with all the sensor elements having one of their ends connected to a row line and other end to a column line. This interconnection overloading results in crosstalk among all the elements. This crosstalk causes the spreading of information over the whole array. The proposed circuit in this method takes care of this effect by minimizing the crosstalk. The circuit makes use of the concept of virtual same potential at the inputs of an operational amplifier in negative feedback to obtain a sufficient isolation among various elements. We theoretically present the suitability of the method for small/moderate sized sensor arrays and experimentally verify the predicted behavior by lock-in-amplifier based measurements on a light dependent resistor (LDR) in a 4 x 4 resistor array. Finally, we present a successful implementation of this method on a 16 x 16 imaging array of LDR. (C) 2008 Elsevier B.V. All rights reserved