Research Of The Temperature Drift Compensation Method Of Piezoresistive Pressure Sensor

Piezoresistive pressure sensor, be made of semiconductor silicon based on piezoresistive phenomenon, has many characteristics of high measurement precision, high sensitivity, good stability, wide working frequency range and being miniaturized and produced easily. It is a new type sensor which developed quickly and used widely. But the piezoresistive pressure sensor always faces an important problem of temperature drift which restricts its application because of temperature characteristics of semiconductor.In this paper, a set of silicon piezoresistive sensor temperature compensation system is proposed to solve the problem of temperature drift. This method makes use of modern signal processing techniques, takes conditioning chip as the core components, use the cubic splint interpolation to fit the compensation parameters. It provides an effective way to realize piezoresistive pressure sensor accuracy compensation for temperature drift. And this system has the capable of compensating eight piezoresistive pressure sensors because of adopting the high performance MCU.The main contents of the paper are as follows:1. This paper discusses the causation of the temperature drift of piezoresistive pressure sensor, then some compensation methods based on hardware and software are analyzed and their principles are summarized. Finally, a novel system of temperature compensating for the piezoresistive pressure sensor is proposed.2. The compensating principle of the MAX1452 has been studied, and then the design of the sensor temperature compensating system is proposed. The compensation principle has been derived.3. The temperature compensation system is divided into several functional modules according to the design requirements. Each of the specific implementations of the module is determined, and the circuits are designed.4. The software of the temperature compensation is developed according to the working principles of the MAX1452, the steps of the compensation is designed. Human-computer interface is designed by using the VC++ and ACCESS data base. The parameters are fitted by using the cubic splint interpolation. 5. Complete the program development for the MCU in MPLAB8.30 development environment. Controlling multiple of pressure sensor compensation module is realized.6. Compensate the piezoresistive pressure sensor by using this sensor temperature compensating system, and test the temperature drift. Experimental data indicates that the non-linearity is smaller than 0.8%F.S, and the thermal drift is also reduced deeply after compensated.