A Sigma-Delta Resistance to Digital Converter Suitable for Differential Resistive Sensors

This paper presents a novel resistance-to-digital converter (RDC) suitable for differential resistive sensors. The proposed RDC provides a digital output linearly proportional to the parameter being sensed by a differential resistive sensor not only for differential resistive sensors possessing linear characteristic but also for sensors possessing inverse characteristic. The proposed RDC is based on the sigma-delta type analog-to-digital converter (Sigma-Delta ADC) principle and hence possesses all the advantages and limitations of a Sigma-Delta ADC. Experimental results on a prototype built and tested gave a worst case error < 0.15 %, establishing the efficacy of the proffered RDC.