Rcs. Freire et al., A HIGHLY LINEAR SINGLE P-N-JUNCTION TEMPERATURE SENSOR, IEEE transactions on instrumentation and measurement, 43(2), 1994, pp. 127-132
A temperature sensor based on the use of two forward-biased p-n juncti
ons is known to exhibit good linearity. An alternative sensor configur
ation, based on the same principle, but employing only one p-n junctio
n is presented in this paper. The forward current through the p-n junc
tion is switched alternately between two fixed values, and the differe
nce between the corresponding voltages is shown to vary linearly with
temperature. This scheme eliminates the problems associated with close
matching required for the two p-n junction sensors. Experimental resu
lts obtained with the proposed scheme are presented. A configuration t
o exploit the temperature dependence of the p-n junction incremental r
esistance is also presented.