Design On High-temperature And High-pressure Differential Pressure Sensor And Characteristics Research

Pressure sensor is an important branch of the sensor family. And reliability and stability of pressure sensors is the sensor technology is the key technology. Differential Pressure sensor is a more complex pressure sensor. Pressure measurements because of the high-temperature material temperature limits, pressure testing has been the need to overcome the problem areas. The project focuses on the design and study of a high temperature, high precision, great pressure, high overload, small size of the pressure sensor to meet defense and civilian needs.Introduce the working principle of the sensor, according to high temperature, big pressure and the technical requirements of overload, and the current domestic and international pressure sensitive materials and production process of development status, select the SOI (silicon on insulator, silicon on insulator) chip as a force-sensitive power conversion components. SOI-sensitive chip has a "top silicon-buried insulating oxide layer-silicon substrate," three-tier structure, can effectively overcome the traditional piezoresistive silicon chip sensitive to high temperature leakage current of PN section, suitable for high temperature high pressure working environment. Meanwhile, to meet the large requirements of small pressure measurement of the mechanical properties of SOI-sensitive chips were analyzed to determine the structure-sensitive chip used "C"-type structure. Using piezoresistive effect, we focused on constant current and constant voltage source power supply power supply analysis. Consider the width of the sensor working temperature in order to ensure high-precision temperature measurement requirements are not affected by the current source power supply.Considering the environment the sensor is used, the mechanical structure and circuit design. According to the program used to determine the sensitivity of the chip, using the finite element analysis of elastic diaphragm SOI chip sensitive to solid modeling, based on sensitivity, linearity and reliability and other factors, on the membrane simulation, optimization. According to the actual needs of the sensor, using the Ritz method (Leeds algorithm), to determine the length of the resistance section (L), width (W), thickness (δ), completed chip layout. The use of three-dimensional modeling software for three-dimensional structure of the sensor modeling, analysis, and structural design of various parts of the sensor is reasonable and the results of the analysis are optimized to achieve the miniaturization of sensors and to ensure structural strength. Using the differential amplifier circuit, temperature compensation circuit is designed, anti-electromagnetic interference circuit design to achieve high-precision sensors, temperature and interference.The use of micro-machining (smart cut) technology, welding and other production process sensors, process simulation tools through the chip sensitive to electrostatic bonding process simulation and optimization, according to the results to determine optimal process parameters. Experimental validation of welding parameters, welding parts were dissected through, measure; verify whether the welding parameters can meet the strength requirements.We tested the performance of the sensor, and also the analysis of experimental data.13 were selected by performance testing of sensors, sensor randomly selected three environmental suitability, the results show that the sensor can meet the high precision, great pressure of overload, small size and strong vibration, big shock, salt spray and other technical indicators.