Calibration-free temperature measurement with bipolar transistors

The use of pn-junctions for temperature measurement has gone through several stages from the simple temperature sensor to the integrated sensor. In this paper we introduce the use of bipolar transistors for a calibration free temperature measurement. The elimination of the need to calibrate enables one to reduce the production and maintenance costs of sensors. Not all known temperature measurement methods using bipolar transistors are able to realize a calibration-free temperature measurement. Even methods realizing a calibration-free temperature measurement like the well-known method by Verster have been used in practice with calibration in order to realize an acceptable accuracy, We propose to use an accurate i-u characteristic model and to take more measured i-u points into account. This improves the accuracy of measurement without affecting the calibration-free behaviour