The working principle of capacitive touch chip
- Aug 01, 2022
Any two conductive objects between the existence of inductive capacitance, a keypad that is a pad and the earth can also constitute an inductive capacitance, in the case of the surrounding environment remains unchanged, the inductive capacitance value is fixed tiny value. When there is a human finger near the touch button, the inductive capacitance between the human finger and the earth in parallel with the inductive capacitance between the pad and the earth will increase the total inductive capacitance value. When the capacitive touch key IC detects a change in the sensing capacitance value of a key, it outputs a definite signal that a key has been pressed. Capacitive touch keys because there is no mechanical structure, all the detection is a small change in power, so it will be more sensitive to various interference, so the touch key design, the design of the touch panel and the choice of touch IC are very critical.
The current use of touch chips are mainly two kinds, one is a resistive touch chip, the other is a capacitive touch chip. Capacitive touch chip is more reliable and more widely used. The current application of touch chip products, single-point touch type is more common and widely used. With the continuous development of touch chips, a variety of forms of touch buttons have appeared in our daily household appliances, such as scroll wheel and slider type keys appear more enriched the application of touch chips.
Early touch chips are relatively simple and can only handle keys. With the further development of technology, the touch chip is no longer a simple button processing chip, now can be used as a master MCU, in addition to handling touch buttons can also handle such as AD sampling, LED control, communication and so on. Previously, to achieve the touch button function must have two chips, a touch chip, a main MCU, now only a touch chip can solve the problem, so that the cost of the product is greatly reduced, but also make more products can use the touch button technology.
Because of the touch chip set into the MCU, the detection of the key has become more flexible, you can use matrix scanning or AD sampling, which makes it possible to identify the number of keys more and more, before it may require several touch chips to complete, now a new touch chip can fully meet the requirements.
The emergence of touch chip technology, so that the way the keys also appeared a huge change, the key operation has become more flexible and comfortable, the key panel has become more fashionable and bright. Touch keys are being used in more and more products with their unique advantages.
With the continuous development of touch technology, the reliability and practicality of the touch chip will be further improved, making the use of the touch chip is also more widespread. At present, the touch chip integration has become increasingly high, the touch chip can do both the main MCU can also do touch keys, which makes the touch chip more cost-effective, lower cost, it is clear that the application of the touch chip will become more and more widespread.