The Key Technology Of Automotive Faceplate With Capacitive Touch Sensor

The automotive design was originated in 1885, the first automotive was invited by Mr. Benz and he received the invention right. The technology of automotive keeps on developing since then. Today, the electrics technique has been the key basic technology for automotive and it will be the trend of automotive in the future.One of the key automotive electrics technologies is faceplate. As the most important HMI device, it contains the control of infotainment, air condition and door control. It provides the communication between human and automotive.So far most switch of faceplate is based on mechanical switch. The life time of it will be limited by the operation times. Normally the max life time of the mechanical switch is 100,000 operation times. Besides, the mechanical switch will need to pass big current; the switch contact point may be damaged. In some failure mode this switch contact is destroyed or even burned by the big current. Moreover, the faceplate with mechanical switch can not satisfy the high end vehicle for more comfortable demand. So this article will research the faceplate of capacitive sensor switch with more life time and comfortable.The faceplate of capacitive sensor may be the trend of the development of automotive in the future. Compared with mechanical faceplate, capacitive faceplate can provide better lifetime and user experience. The key parameter of capacitive sensor are sensitive and SNR. So the purpose of this article is to optimally design the cap sensor to meet the sensitive and SNR, then apply this technology into automotive faceplate.The main content of this article is as below:The first part is to compare and analyze current automotive faceplate, provide the solution of cap sensor faceplate.The second part is to introduce the basic principle of the cap sensor technology, list different types of the cap sensor.The third part is to design the product including hardware and software design. It will contain the schematic and layout design, the worst case calculation including short to battery and ground, ripple and overvoltage. The software will contain the basic function of cap sensor faceplate, the flowchart and C code by PSOC.The fourth part is the verification. The hardware and software will be combined to verify and simulate. The data and chart of the cap sensor will be recorded and analyzed. The result shows that the sensitive and SNR is good enough to meet the optimal design of the faceplate of the capacitive sensor. All function can be met. Comparing with the mechanical switch, it is more reliable and sensitive.The last part is to summarize all the research of the cap sensor faceplate, and then propose the next step of advanced design.