A Design Of The MEMS Digital Pressure Sensor

Nowdays is a society of information explosion, the development of society more and more depends on all kinds of information. How to get all kinds of information quickly, conveniently and accurately has become a difficult challenge that we must face. Pressure is one of the important parameters which play a crucial role in all aspects of society as a widely used information. Pressure sensor obtains more and more attention as an effective way to get pressure message in many industry and research fileds. With the development of the technology, the pressure sensor shows the tendency towards the miniaturization n intelligence and systematization, and the digital pressure sensor is coincided with this trend.Compared with the traditional pressure sensor, the digital pressure sensor owns unique advantages in the aspect of the intelligence and systematization. Traditional pressure sensor has the output of analog signal, which is easy to be interfered, moreover, the traditional pressure sensor can not match with the microprocessor quite well. The digital pressure sensor does not have such restrictions. With the development of the MEMS (Micro-Electro-Mechanical Systems) technology, the digital pressure sensor can have much smaller volume, much lower cost and much higher reliability. Additionally, the digital pressure sensor also can hold the ability to do the self-calibration with built-in data processing chip, and use the communication interface to make up sensor network.In this paper, a digital pressure sensor was designed based on the sensor signal conditioner (SSC) of ZMDI and the silicon piezoresisitive pressure sensor which was designed by our own group. The proposed digital pressure sensor could realize the digital output and the temperature drift, the zero-drift, linearity as well as the hysteresis could be calibrated as well. The main work of this thesis contain the following aspects:1. In this paper, a set of method about sensor testing was summarized. A performance testing for the MEMS sensor was carried out to verify the MEMS sensor has great characteristics of linearity, hysteresis, repeatability and so on.2. A joint debugging was carried out between the sensor and the sensor signal conditioner. The analog output of the MEMS sensor could be converted to digital signal through amplification, bias and analog-to-digital conversion. After that, the digital signal was calibrated by DSP. At last, this calibrated data could be exported through the communication interface.3. Do research on the sensor package. Meanwhile, multi-chip scale package was used. Finally, an integrated digital pressure sensor was obtained.4. In the end, the calibration was set to the integrated sensor. And a testing was carried out for the sensor performance. With the analyzation of the performance results, the conclusion has been obtained that the performance matched the target very well, the accuracy of which is 4%o. At the end of the paper, some improvement suggestions have been summarized.In this paper, the output of the digital pressure sensor is calibrated. And the digital pressure sensor is intergrated with the signal processing circuit which made it suitable for the applications such as the the altituder, the barometer, the dropsonde and so on. With the decrease of the volume of the package, the digital pressure sensor can also be suitable for the applications of small volume. To sum up, the deisgned digital pressure sensor in the paper shows a certain theoretical and practical value.