Design and Experimental Research of a Temperature Compensation System for Silicon-on-Sapphire Pressure Sensors

A temperature compensation system is designed and fabricated to eliminate temperature effects, which will significantly affect the measuring precision for the silicon-on-sapphire pressure sensor. This system uses a high precision temperature sensor and a high-performance digital circuit to achieve the temperature compensation. It is mainly composed of a temperature sensor (PT100), analog filters, a highly integrated chip with two 24-bit analog-to-digital converters, two programmable gain amplifiers, and an on-chip processor. Temperature drift of the sensor under each temperature point is modified and compensated by using the high precision temperature sensor and the self-programed algorithm. Theoretical and experimental results indicate that the output of the sensor has an excellent linear relationship with pressure at the same temperature and a parabola relationship with temperature under a certain pressure. So the compensation algorithm combining the least square method and parabolic interpolation method is designed. Finally, the fabricated device is verified by experiments under high temperature and high pressure. It is concluded from the results that the compensated sensor reaches a high accuracy of 0.1% FS in the temperature range of -20 degrees C-140 degrees C and a maximum error of 0.30% FS in the full temperature range (-20 degrees C-250 degrees C). Temperature effects on the pressure measurement decrease more than ten times when the compensation technique is applied.