Pressure sensor has a lot of parameters, one of which is overload protection, overload is too large load, more than the rated load of the equipment itself, the phenomenon is that the current is too large, electrical equipment heating, long-term overload of the line will reduce the line insulation level, and even burn the sensor equipment or line; Overload protection is that even if the load exceeds the rated load, there will be no burning out of the line, but there is also a degree, generally within the range of 150%, and can not continue to overload work.

There are many forms of pressure sensors, each structural form of overload protection design method is also different, many methods have their own advantages and disadvantages, using MEMS technology of small range, highly sensitive pressure sensors are usually flat film, island film, beam film and other structures, in the design of overload protection, generally using convex and other methods to achieve. The forming methods include back etching technology, silicon direct bonding technology, glass etching technology, etc. However, these structures generally have a big limitation that the cavity size is large, further improving the sensitivity is limited, and reduces the silicon wafer utilization rate, increases the complexity of the manufacturing process, and increases the production cost.

At present, the research hotspot of small range and high sensitivity pressure sensor focuses on the sacrificial layer structure pressure sensor, mainly because the elastic diaphragm of the sacrificial layer structure pressure sensor is very thin, the thickness can be 2μm or even thinner. On such a thin structure, if the diffused silicon or polysilicon film is used as the strain resistance of the sacrificial layer structure pressure sensor, its thickness is relatively large, which has a great impact on the stress distribution of the elastic diaphragm, which is not conducive to the optimization of the performance of the sacrificial layer structure pressure sensor. Therefore, the use of polysilicon nano-film to make strain resistance can better play the advantages of the sacrificial layer technology.

Overload protection is considered for each sensor, because the measured value may be greater than the range during use, and only the sensor with overload protection can be better used and can be used longer. How the overload protection of each sensor is designed, and how much the overload range is different, so no matter what kind of sensor you buy, you must understand how much its overload protection is, so that it can be better and easier to use, and there will be no overload burn out circuit in the future use process. The above is to introduce the overload consequences and protection methods of pressure sensors.