Algorithm Execution Time and Accuracy of NTC Thermistor-Based Temperature Measurements in Time-Critical Applications

This paper addresses the challenges of selecting a suitable method for negative temperature coefficient (NTC) thermistor-based measurement in electronic devices. Although accuracy is great importance, calculation time represents an even greater challenge since it inherently constrained by control algorithm executed microcontroller (MCU). Firstly, simple signal conditioning circuit with NTC thermistor introduced, resulting temperature-dependent voltage UT being connected to MCU’s analog input. Next, simulation-based approximation actual vs. curve derived, four notations: look-up table principle, polynomial approximation, B equation and Steinhart–Hart equation. Within simulation results, expected error individual methods calculated, whereas experimental part, performed on DC/DC converter prototype, required prework available MCU resources are evaluated. In terms accuracy, offer superior results over equation, especially nominal range thermistor. However, prework, inferior compared despite latter having far more complex mathematical functions, affecting overall execution significantly.