Stability analysis of a proposed charge balance A/D converter for load cell signal acquisition

Abstract

This article proposed and discussed a kind of sigma-delta A/D converter for load cell signal acquisition, which uses improved charge balance technique. The traditional charge balance sigma-delta A/D converter is stable if and only if the magnitude of the input signal current is less than one half the magnitude of the reference current, which limits the accuracy improvement of load cell. This article examined the stability of an improved version of the charge balance sigma-delta A/D converter. The proposed converter can be designed to be stable for input signals as large as the reference, which is helpful to improve load cell’s measurement accuracy.