P2.9.6 Analog Wheatstone Bridge-Based Automatic Interface for Grounded and Floating Wide-Range Resistive Sensors
- 14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
- P2.9 Technology and Application
- A. De Marcellis, G. Ferri, P. Mantenuto - University of L'Aquila, Department of Electrical and Information Engineering (Italy)
- 1710 - 1713
An analog interface, based on a modified Wheatstone bridge configuration, for the automatic estimation of grounded and floating wide-range resistive sensors is here presented. The circuit maintains the simplicity of the traditional bridge topology but, through a suitable feedback loop, provides the continuous equilibrium condition employing a Voltage Controlled Resistor (VCR) that avoids any initial calibration. This feature allows the circuit to operate for a much larger variation of sensor resistances (with respect to the basic bridge) that can show a variable/unknown baseline, related to both different physical-chemical parameters and fabrication processes. Preliminary experimental measurements have shown the system capability to estimate about five decades of both grounded and floating resistance variations with a more reduced relative error (<2% in the full range, <0.65% in 1.6 decades) when compared to typical wide-range interfaces performing the Resistanceto-Time (R-T) conversion.