Comparison of Thermo-Resistive and Thermo-Electronic Transduction Methods in Thermal Flow Sensors

This paper investigates the differences between thermo-resistive and thermo-electronic flow sensors across 5 SOI CMOS designs. The two transduction principles (hot wire and thermo-diode) are both embedded within the same sensor, allowing for the first time, a fair and complete comparison. Results show that with the reduction in sensor size, the sensitivity and accuracy of thermo-resistive methods becomes worse. The thermo-electronic sensitivity is less significantly affected and the accuracy is unaffected by sensor and heater size. The length of the diode has been found to affect the non-linearity of the electro-thermal properties due to relative significance of current leakage. However, a shorter diode showed 50 % higher accuracy due to it measuring an average higher temperature. This paper can be used as a design tool for those choosing transduction methods within their sensors.