Analog Linearization of Resistance Temperature Detectors (RTD) Using the Intrinsic Curvature of BandGap Voltage References
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Data
2018-01-01
Autores
Carvalhaes-Dias, P.
Ferreira, I. P.
Oliveira Morais, F. J. [UNESP]
Caparroz Duarte, L. F.
Siqueira Dias, J. A.
Yurish, S. Y.
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Editor
Int Frequency Sensor Assoc-ifsa
Resumo
Although resistance temperature detectors (RTD) are more linear than thermocouples, they present second and third order non-linearities, and a linear signal processing circuit which converts the voltage on a Pt-100 RTD to an output voltage with 10 mV/degrees C presents a maximum non-linearity error of 1.07 degrees C (10.7 mV) in the 0 to 85 degrees C temperature range. Although these non-linearities can be corrected digitally, there are cases where a simple analog linearization can be used with advantages. In this work we present an analog linearization technique that uses the output of a conventional Brokaw bandgap cell as the reference voltage of a differential instrumentation amplifier. The intrinsic curvature of the bandgap voltage reference, caused by the non-linear variation with temperature of the VBE of a transistor, creates a compensation voltage that can reduce the non-linearity of the signal processing circuit by one order of magnitude (down to approximately 0.14 degrees C) in the same temperature range.
Descrição
Palavras-chave
RTD, Bandgap curvature, Brokaw cell, Linearization, Temperature sensors
Como citar
Sensors And Electronic Instrumentation Advances (seia'2018). Barcelona: Int Frequency Sensor Assoc-ifsa, p. 68-71, 2018.