An Analog Front-End Using Feedback Compensation Technique for Thermistor Linearization

Thermistors are widely employed for temperature sensing in a number of industrial scenarios. The transfer characteristics of thermistor follows a nonlinear curve. This paper proffers a simple analog front-end circuit that can linearize thermistor characteristics. The front end operates based on a dual-mode feedback compensation principle. The design and optimization of the front-end is discussed in the paper. The front-end, equipped with the optimized values for passive components, can render a non-linearity as low as 0.35% for a wide temperature range. The effect of drift and tolerance of optimization variables are analysed. Further, the efficacy of the front-end has been established using simulation and experimental studies with thermistor characteristics. Experimental results of the developed thermistor front-end gives a non-linearity of 0.57% over a temperature span of 120°C.