Evaluation of New Digital Signal Conditioning Techniques for Resistive Sensors in Some Practically Relevant Scenarios

Abstract

Resistive sensors, with wide-span of operation, are used in a number of industrial scenarios. In some of these cases, such resistive sensors may need to be located in a remote environment, away from the electronics unit. This article brings-forth new and efficient digital signal conditioning techniques to interface the aforementioned classes of resistive sensors. The first proposed technique employs a simple circuitry that requires a single reference voltage and single operation cycle and provides a direct-digital output proportional to the sensor-resistance. Next, this scheme is further enhanced, with the addition of few auxiliary components, to address the case of remotely-located resistive sensors. The novel circuit-designs also ensure other positive features like: 1) short execution time; 2) compatibility to resistive sensors in different configurations; and 3) negligible dependence on many nonideal parameters. The proposed schemes are systematically presented and thoroughly analyzed in this article. Elaborate simulation and emulation studies are used to evidence the performance. A maximum nonlinearity of 0.07% and 12-bit resolution is obtained for the first digitizer, during the hardware tests. The utility of the schemes to interface a temperature sensor with wide-span is also studied. Vital performance parameters of the schemes are derived and compared with the state-of-art works.