Temperature measurement by means of semiconductor diode in pulse mode

Abstract

In case of temperature measurement utilizing forward-biased pn junction, a polarization current is necessary because it is what indicates the pn diode into an operating mode. Simultaneously, with the diode into the operating mode, the polarization current heats the pn junction and impedes measurement. The usual solution to this problem is to reduce the current through the diode. If the current is passed through the diode only at the moment of measurement and for a single brief impulse, the average current, as well as the amount of heat given off to the pn junction, is drastically reduced. The described pulsed-diode thermometer has an average relative error (within 20–100 °C range) of ΔT/T=0.25%.