An Efficient Universal Digitizer With Linear Transfer Characteristic for Resistive Sensor Bridges
K Elangovan, Anoop Chandrika Sreekantan
Abstract
A simple digitizer circuit suitable for bridge-based resistive sensors is reported in this article. The digitizer provides a linear transfer characteristic, for all common types of resistive bridges. Besides, the digitizer output is independent of the parasitic capacitance of the resistive sensors, connecting wire impedances, and mismatch among the bridge elements. The methodology of the digitizer is mathematically derived and analyzed. A number of experimental studies of the digitizer are carried out with various types of bridge configurations. Linear output characteristic, with all other expected meritorious features, is obtained during all these tests, and the maximum output nonlinearity is less than 0.06%. Tests are also conducted with an industrial magnetoresistance (MR) sensor bridge. The results demonstrate a magnetic sensing system with higher performance when compared with the conventional interface for MR sensors.