Evaluation of a Digital Converter for Linear and Nonlinear Temperature Sensors

Abstract

A simple digital converter suitable for linear and nonlinear temperature sensor is proposed in this paper. This digital converter uses easily-available analog components and a digital time measurement unit in its architecture. The converter uses the same hardware architecture for both linear and nonlinear sensors. Novel linearization approaches are used to extract a linear output in case of nonlinear sensors. The circuit also provides other desired features like independence from power-supply drifts and many Op-amp non-idealities. The methodology of the converter and design/linearization approaches used are explained in the paper. The possible error sources of the circuit are also analyzed theoretically in this paper. These studies show that the developed converter can serve as an accurate and efficient interface for temperature sensors. The performance of the digital converter is verified by conducting various (simulation and experimental) studies on linear and nonlinear temperature sensors. The linearization capability of the scheme, in the case of nonlinear sensors is also clearly illustrated in the paper.