Modelling of the reverse current and its effects on the thermal drift of the offset voltage for piezoresistive pressure sensors

Autor: Yi Zhang, Yi Cai Sun, Li Qiang Tian, Zhenbin Gao
Rok vydání: 2004
Předmět:
Zdroj: Sensors and Actuators A: Physical. 116:125-132
ISSN: 0924-4247
DOI: 10.1016/j.sna.2004.01.064
Popis: A theoretical model of the reverse current for piezoresistors has been developed in order to study the thermal behaviour of the offset voltage. According to this model and taking account of the difference of the temperature coefficients among four piezoresistors and thermal behaviour of the reverse current, an expression can be obtained, showing thermal variations of the offset voltage. We have computed the thermal variations of the output for a half bridge as well as for the whole bridge, plotted them versus temperature and obtained several typical graphs. Because of the effect of the reverse current, the graph curves are much complicated than the parabola, as the model of the mismatch of TCRs predicts. The reverse current has a great influence on the thermal drift of output for the half bridges as well as the whole bridge. The maximum or minimum temperatures for thermal drift curves, if existed, are usually situated at the temperatures beyond ∼50 °C, depending upon the magnitude of the reverse current. The lower is the reverse current, the higher are the maximum or minimum temperatures and then the lower is the thermal variation of the offset voltage. We believe that only when the reverse current is lower, the thermal behaviour of the offset voltage is governed by a parabolic low, or the curves representing the thermal drift of it will be a branch of a parabola.
Databáze: OpenAIRE
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