Touch screen control circuit
By using four touch chips to share the I/O ports and adding digital isolation circuits in the touch screen control circuit, the problems of MCU pin occupation and circuit instability are solved, and the cost saving and stability are achieved.
Patent Information
- Application Number
- CN202421926413.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2025-07-08
- Estimated Expiration
- 2034-08-09
AI Technical Summary
In the existing touch screen control circuit, multiple touch chips occupy many MCU control pins and lack effective ground-electric floating noise processing, resulting in unstable circuits.
Four touch chips share the I/O ports and are connected to the touch MCU through a one-way isolation I/O chip. Digital isolation circuit is added to isolate the signal. The touch MCU models are Tango U448 and one-way isolation I/O chip to reduce pin usage and enhance stability.
It saves the number of MCU pins and unidirectional isolation I/O chips, improves circuit stability and anti-interference ability, and improves the signal-to-noise ratio and touch control effect of the touch screen.
Smart Images
Figure CN223078672U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of touch display technology, and particularly to a touch screen control circuit. Background Art
[0002] In the existing touch screen control circuit, the I / O ports of one touch chip occupy a group of I / O parts of a touch MCU. In the case of a large-size solution that requires multiple touch chips, a large number of MCU control pins will be occupied.
[0003] However, the existing touch screen control circuit does not add an I / O isolation circuit. The touch chip and the touch MCU share the same ground, and there is also relatively little processing of floating noise to the ground in the circuit. Content of the Utility Model
[0004] The object of the present utility model is achieved through the following technical solutions.
[0005] Specifically, the present utility model provides a touch screen control circuit, including:
[0006] Four touch chips, three unidirectional isolation I / O chips, and one touch MCU;
[0007] Among the I / O interfaces of the four touch chips, the FSPI2_MOSI pins of the four touch chips are connected to each other and then connected to each unidirectional isolation I / O chip, the FSPI2_MISO pins of the four touch chips are connected to each other and then connected to each unidirectional isolation I / O chip, the FSPI2_CLK pins of the four touch chips are connected to each other and then connected to each unidirectional isolation I / O chip, and each unidirectional isolation I / O chip is also respectively connected to the touch MCU.
[0008] Further, the model of each touch chip is F109.
[0009] Further, the peripheral circuit of each touch chip includes four capacitors, one resistor, and one TVS diode.
[0010] Further, the peripheral circuit of the unidirectional isolation I / O chip includes four capacitors and six resistors.
[0011] Further, the model of the touch MCU is Tango U448.
[0012] Further, the peripheral circuit of the touch MCU includes six capacitors and two resistors.
[0013] The advantages of the present utility model are as follows:
[0014] Adopt the method of connecting multiple touch ICs to share the I / O ports to the touch MCU, and add a group of digital isolation circuits between the two, which can not only save the pins used by the touch MCU, but also save the number of one-way isolation I / O chips. Brief Description of the Drawings
[0015] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:
[0016] Figure 1 Shows the schematic diagram of the overall circuit pins according to the embodiment of the present invention.
[0017] Figure 2 Shows the overall circuit architecture diagram according to the embodiment of the present invention.
[0018] Figure 3 Is the peripheral circuit diagram of the touch chip of the present invention.
[0019] Figure 4 Is the peripheral circuit diagram of the one-way isolation I / O chip of the present invention.
[0020] Figure 5 Is the peripheral circuit diagram of the touch MCU of the present invention. Detailed Embodiments
[0021] The following will describe the exemplary embodiments of the present disclosure in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully communicated to those skilled in the art.
[0022] The present invention adds a multi-channel digital isolator with an integrated isolated DC-DC power supply on the basis of a common touch circuit, which is mainly used for signal isolation, and different output voltages can be set through this chip, and it has enhanced system-level ESD, EFT, and surge resistance capabilities, which can effectively improve the stability of the circuit.
[0023] Such as Figure 1As shown in the figure, taking the large-size touch control solution as an example, the present utility model uses four touch control chips with a total of 4 groups of I / O ports. Among them, the three pin feet of FSPI2_MOSI, FSPI2_MISO, and FSPI2_CLK are all connected together and connected to the touch control MCU (U4) through the unidirectional isolation I / O chips (U1, U2, U3). This can not only save the number of unidirectional isolation I / O chips but also save the pins of the touch control MCU. Compared with the ordinary solution, it can reduce the occupation of 9 channels. Therefore, an MCU with a lower cost and a smaller package can be selected. Similarly, the power supply and ground are also processed through this digital isolation area.
[0024] As Figure 2 shown, a touch screen control circuit of the present utility model includes:
[0025] Four touch control chips, three unidirectional isolation I / O chips, and one touch control MCU;
[0026] Among the I / O interfaces of the four touch control chips, the FSPI2_MOSI pin feet of the four touch control chips are connected to each other and then connected to each unidirectional isolation I / O chip; the FSPI2_MISO pin feet of the four touch control chips are connected to each other and then connected to each unidirectional isolation I / O chip; the FSPI2_CLK pin feet of the four touch control chips are connected to each other and then connected to each unidirectional isolation I / O chip. Each unidirectional isolation I / O chip is also respectively connected to the touch control MCU.
[0027] Figure 3 This is the peripheral circuit diagram of the touch control chip of the present utility model. Taking one of the 4 touch control chips, S1, as an example, the circuits of the other 3 touch control chips are similar to that of S1. FSPI2_SS, FSPI2_SS1, FSPI2_SS2, and FSPI2_SS3 are respectively located on the four chips. The network name of the ground of the touch control chips (S1, S2, S3, S4) is GND2, which is also isolated from the ground VSS of the touch control chip (U2) through the unidirectional isolation I / O chip. The model of the touch control chip is F109, and the package is LQFP128. The peripheral circuit of each touch control chip includes four capacitors, one resistor, and one TVS diode. Figure 4 This is the peripheral circuit diagram of the unidirectional isolation I / O chip of the present utility model. Taking one of the 3 unidirectional isolation I / O chips, U1, as an example, the circuits of the other 2 unidirectional isolation I / O chips are similar to that of S1. The peripheral circuit of the unidirectional isolation I / O chip includes four capacitors and six resistors. Since this peripheral circuit belongs to the prior art, it will not be elaborated here. The signal after digital isolation can effectively reduce the common-mode noise, enhance the stability and anti-interference ability of the system, enable the touch screen to achieve a better signal-to-noise ratio, and greatly improve the touch control effect.
[0028] Figure 5This is the peripheral circuit diagram of the touch MCU of the present utility model. The model of the touch MCU is Tango U448. The peripheral circuit of the touch MCU includes six capacitors and two resistors. Since this peripheral circuit belongs to the prior art, it will not be elaborated here.
[0029] The present utility model adopts a single I / O isolation circuit, which can effectively isolate the communication line between the touch chip and the touch MCU.
[0030] On the basis of controlling costs, it can improve the interface ability of the circuit, reduce common-mode noise, and enhance the stability and anti-interference ability of the system.
[0031] The scheme of sharing I / O ports can effectively reduce the problem that the pins of large-size touch MCUs are occupied too much.
[0032] The above is only the preferred specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present utility model should be covered by the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claims.
Claims
1. A touch screen control circuit, characterized in that Including: Four touch chips, three one-way isolation I / O chips, and one touch MCU; Among the I / O interfaces of the four touch chips, the FSPI2_MOSI pins of the four touch chips are connected to each other and then connected to each one-way isolation I / O chip, the FSPI2_MISO pins of the four touch chips are connected to each other and then connected to each one-way isolation I / O chip, the FSPI2_CLK pins of the four touch chips are connected to each other and then connected to each one-way isolation I / O chip, and each one-way isolation I / O chip is also respectively connected to the touch MCU.
2. The touch screen control circuit according to claim 1, characterized in that The model of each touch chip is F109.
3. The touch screen control circuit according to claim 1 or 2, characterized in that The peripheral circuit of each touch chip includes four capacitors, one resistor, and one TVS diode.
4. The touch screen control circuit according to claim 1, characterized in that The peripheral circuit of the one-way isolation I / O chip includes four capacitors and six resistors.
5. The touch screen control circuit according to claim 1, characterized in that The model of the touch MCU is Tango U448.
6. The touch screen control circuit according to claim 1 or 5, characterized in that The peripheral circuit of the touch MCU includes six capacitors and two resistors.