A direct-digital converter for resistive sensor elements in bridge configuration

Abstract

A dual slope direct digital converter (DDC) suitable for resistive sensor elements already connected in the form of a Wheatstone bridge is presented here. The proposed DDC accepts the whole bridge as an integral part of a dual slope analog to digital converter and provides a digital value proportional to the input quantity being sensed by the four resistive sensing elements of the bridge. Simulation studies establish the efficacy of the proposed DDC. Maximum error observed in the simulation study was <; ± 0.25 %. To demonstrate the practicability of the proffered DDC, experiments were conducted on a prototype DDC. The error in the output of the of the prototype was found to be <; ± 0.5 %.