The three major challenges of capacitive touch screen technology are: signal detection, parasitic capacitance changes, and power consumption and size.
1) Signal detection. Existing algorithms are difficult to distinguish between noise and signal. Separating useful signals from signal sources is also a major difficulty in algorithm development.
2) Changes in parasitic capacitance. The working principle of the capacitive touch screen is to generate capacitance through the contact of the finger with the touch screen, and the position information is obtained by calculating the capacitance value. However, the design of various touch screen products on the market nowadays is very different, and the panel materials, shells, and PCB sizes used by different manufacturers are also different. Therefore, the touch screen solution provider needs to adjust the capacitance value correspondingly to match it for different designs. However, due to product process issues, even the same series of products from the same manufacturer may need to carefully check and calibrate the parasitic capacitance value. Therefore, during the entire product design process, 1C design companies, panel manufacturers, and terminal design manufacturers need to work closely together, follow up in time, and respond quickly to design issues. Only in this way can the product be quickly introduced to the market.
3) Power consumption and PCB size. Low power consumption and miniaturization are the inevitable trends of 1C design. How to reduce power consumption and size while ensuring performance is also the goal of product design.
In order to meet the above challenges, Cypress has developed a Smart Sense programmable Cap Sense touch screen solution. It uses an algorithm independently developed by Cypress to solve the above problems. This solution has the following advantages: No manual adjustment is required, the threshold can be self-adjusted, the technical difficulty is reduced, the later testing steps of the designer are omitted, the BOM cost can be reduced, and the time to market can be shortened.
