CN105589609A

CN105589609A - Anti-interference module of mutual capacitance touch chip

Info

Publication number: CN105589609A
Application number: CN201410573418.1A
Authority: CN
Inventors: 杨艳
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-10-24
Filing date: 2014-10-24
Publication date: 2016-05-18

Abstract

A mutual capacitance touch screen is a touch screen which is most widely applied in a traditional touch screen market, but the mutual capacitance touch screen is always interfered by outside noise and needs to own high noise inhibition capability. The invention provides a noise inhibition module embedded in a touch chip from an angle of chip hardware design so as to improve the anti-noise capability of the touch chip and further improve the signal to noise ratio of the mutual capacitance touch screen.

Description

A kind of mutual capacitance touch-control chip immunity module

Technical field

The present invention relates to a kind of chip immunity module, especially a kind of mutual capacitance chip immunity module.

Background technology

Touch screen technology is a kind of application human-computer interaction technology more and more widely. This technology allows user to click on the icon of display screen or word, just can allow system carry out the various operations of correspondence according to user's instruction, and it makes man-machine interaction break away from the constraint of mouse and keyboard, becomes more personalized and hommization. Current, touch screen technology has almost penetrated into all consumer electronics market, and becomes one of attraction of a lot of electronic product maximums. And in the touch-screen based on different technologies principle, mutual capacitance type touch screen is experienced because of its outstanding multiple point touching, become the most popular a kind of touch-screen of Vehicles Collected from Market. But mutual capacitance type touch screen is to detect finger touch and definite touch location against the minor variations of detecting touch-screen electric capacity, be easy to be subject to the interference of outside noise, thereby reducing the degree of accuracy and reliability reduces, even there is false touch, and along with touch-screen size is increasing, more and more frivolous, it is more and more serious that the interference of noise also becomes, reduce thereby reduce the degree of accuracy and reliability, even occur false touch. For general electronic equipment, noise mainly comes from the noise of display and the noise of charger, and their impact is the most great, also the most difficult, more and more needs stronger noise inhibiting ability with mutual capacitance touchscreens.

Summary of the invention

In order to solve the problem of the interference that is easily subject to outside noise of above-mentioned existence, the invention provides a kind of mutual capacitance touch-control chip immunity module.

A kind of mutual capacitance touch-control chip immunity module, comprise sensemodule (contact sense module), ADC (digital to analog converter), SRAM (static access facility internal memory), EmbededMCU (embedded scm) and drivermodule (driver module), and be connected with contact panel part. It is characterized in that, between original ADC and SRAM, increased a new SRAM and a noise suppression module, claimed that the SRAM newly increasing is SRAM1 here, original is SRAM2, wherein SRAM1 is for storing the data of same a line, and SRAM2 is used for the data of storing a frame. In noise suppression module, design two register scan[3:0] and filter[3:0] control wherein scan[3:0] be used for controlling the scanning times of every a line, filter[3:0] be used for controlling the number of the data that filter out. Scanning times scan[3:0] scope is set to 1 ~ 6 time, leaches the filter[3:0 that counts] must with scanning times scan[3:0] parity is identical.

Beneficial effect of the present invention: by having increased new SRAM and noise suppression module, improved the anti-noise ability of touch-control chip, and further improved the signal to noise ratio of mutual capacitance type touch screen. And simplicity of design, can not consume the too many resource of chip.

As a preferred embodiment of the present invention, the model of the SRAM that noise suppression module increases can be 20*11*6bit.

Brief description of the drawings

Fig. 1 is mutual capacitance touch-control chip immunity module Organization Chart.

Wherein, 1 is sensemodule, and 2 is ADC, and 3 is SRAM1, and 4 is noise suppression module, and 5 is SRAM2, and 6 is Drivermodule, and 7 is touchcontrollerIC, and 8 is TPSmodle.

Detailed description of the invention

A kind of mutual capacitance touch-control chip immunity module as shown in Figure 1, comprises sensemodule1, ADC2, SRAM5, EmbededMCU and drivermodule6, and is connected with contact panel part. The touch-control chip of appearance formula touch-screen is responsible for controlling the scanning process of touch-screen mutually, and can judge according to the variation of the induced voltage on induction electrode the coordinate of touch action occurrence positions, driver module in touch-control chip is used for producing pumping signal, is connected with the drive electrode on contact panel. Induction module is connected with the induction electrode on contact panel, and it can detect the induced voltage on induction electrode. The magnitude of voltage that induction module ADC2 below can detect induction module is transformed into data signal, and is stored in SRAM15. After a frame scan, the data in SRAM15 can be read in touch-control chip and process in Embedded MCU, and Embedded MCU can send to the coordinate of touch action occurrence positions the central processing unit of system in the time judging touch location.

A kind of mutual capacitance touch-control chip immunity module as shown in Figure 1, it is characterized in that: between original ADC2 and SRAM5, increased a new SRAM3 and a noise suppression module 4, wherein SRAM13 is for storing the data of same a line, the data of SRAM25 for storing a frame, when touch-screen work, can carry out continuously Multiple-Scan to same a line, deposit the result of this line scanning in SRAM13, after this line scanning finishes, noise suppression module can read respectively the data of each row in this line, then the scanning result several times of same position is carried out to noise reduction process, then deposit the data of this line in SRAM25, and finally output. in noise suppression module 4, design two register scan[3:0] and filter[3:0] control wherein scan[3:0] be used for controlling the scanning times of every a line, filter[3:0] be used for controlling the number of the data that filter out. because consider that too much scanning times can affect the response times of touch-screen, so scanning times scan[3:0] scope is set to 1 ~ 6 time, leaches the filter[3:0 that counts] must with scanning times scan[3:0] parity is identical. noise reduction algorithm has been taked sequence, and gets the method for data summation placed in the middle.

Embodiment 1: in noise suppression module 4, scan[3:0] be 1, filter[3:0] be 1, now noise suppression module lost efficacy, when collecting 50 frame data, when every frame has comprised 11 driving passages and 19 induction channels, noise mean value is 0.0126716, and noise variance value is 0.91513.

Embodiment 2: in noise suppression module 4, scan[3:0] be 5, filter[3:0] be 3, now noise suppression module is effective, when collecting 50 frame data, when every frame has comprised 11 driving passages and 19 induction channels, noise mean value is 0.0163636, and noise variance value is 12.4382.

Embodiment 3: in noise suppression module 4, scan[3:0] be 5, filter[3:0] be 1, now noise suppression module is effective, when collecting 50 frame data, when every frame has comprised 11 driving passages and 19 induction channels, noise mean value is 0.0168765, and noise variance value is 10.4862.

This noise mean value of three groups of embodiment 1, embodiment 2 and embodiment 3 is more or less the same, and the experimental variance of 0, embodiment 2 and embodiment 3 of all leveling off to is larger than the variance yields of embodiment 1, but is far smaller than 3 times of levels. And the signal level than embodiment 1 is increased by 3 times by the signal level of embodiment 2 and embodiment 3, noise suppression module can effectively improve the signal to noise ratio of touch-screen as can be seen here, thereby touch action is more easily identified.

Claims

1. a mutual capacitance touch-control chip immunity module, comprise a kind of mutual capacitance touch-control chip immunity module, comprise sensemodule, ADC, SRAM, EmbededMCU and drivermodule, and be connected with contact panel part, it is characterized in that: between original ADC and SRAM, increased a new SRAM and a noise suppression module.

2. a kind of mutual capacitance touch-control chip immunity module according to claim 1, it is characterized in that: in noise suppression module, be provided with two register scan[3:0] and filter[3:0] control, scanning times scan[3:0] scope is set to 1 ~ 6 time, leaches the filter[3:0 that counts] must with scanning times scan[3:0] parity is identical.

3. a kind of mutual capacitance touch-control chip immunity module according to claim 1, is characterized in that: the model of the SRAM that noise suppression module increases is 20*11*6bit.

4. mutual capacitance touch-control chip immunity module according to claim 2, it is characterized in that: scan[3:0] be 5, filter[3:0] be 3, now noise suppression module is effective, when collecting 50 frame data, when every frame has comprised 11 driving passages and 19 induction channels, noise mean value is 0.0163636, and noise variance value is 12.4382.

5. mutual capacitance touch-control chip immunity module according to claim 2, it is characterized in that: scan[3:0] be 5, filter[3:0] be 1, now noise suppression module is effective, when collecting 50 frame data, when every frame has comprised 11 driving passages and 19 induction channels, noise mean value is 0.0168765, and noise variance value is 10.4862.