Touch controller, synchronization method, chip and electronic equipment

Abstract

The invention discloses a touch controller, a synchronization method, a chip and electronic equipment, and belongs to the technical field of touch control. Taking the touch controller as a first touch controller as an example, the demodulation unit is used for receiving and demodulating a first sensing signal transmitted by the first receiving electrode to obtain a first demodulation signal, and the first sensing signal is generated based on a first driving signal transmitted by the driving module to the first transmitting electrode. And the automatic correlator is used for resetting the first frequency divider according to the first demodulation signal so as to be synchronized with the second frequency divider of the second touch controller. The demodulation unit is further used for receiving and demodulating the second sensing signal transmitted by the first receiving electrode for multiple times to obtain second demodulation signals with multiple frequencies, and the second demodulation signals with the multiple frequencies are used for correcting the frequency and the phase of the first clock unit so as to be synchronized with a second clock unit of the second touch controller. Synchronization between different touch controllers is achieved, and the method and device are suitable for the scene that different touch sensors are cascaded.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of touch control technology, and in particular to a touch controller, a synchronization method, a chip, and an electronic device. Background Art

[0002] With the development of touch technology, many devices are equipped with touch sensors. The touch sensor includes coupled transmitting electrodes and receiving electrodes. When the touch sensor has a large area, the coupled transmitting electrodes and receiving electrodes are respectively connected to different touch controllers, so different touch controllers need to be synchronized. How to achieve synchronization has become a problem worthy of attention. Summary of the invention

[0003] The embodiments of the present application provide a touch controller, a synchronization method, a chip and an electronic device, which can be used to achieve synchronization between different touch controllers. The technical solution includes the following aspects.

[0004] In a first aspect, a touch controller is provided, characterized in that the touch controller is a first touch controller, the first touch controller includes a first frequency divider, an autocorrelator, a first clock unit and a demodulation unit, the first frequency divider is respectively connected to the autocorrelator, the first clock unit and the demodulation unit, the demodulation unit is also respectively connected to the autocorrelator and a first receiving electrode of the touch sensor, the first receiving electrode is coupled to the first transmitting electrode of the touch sensor, and the first transmitting electrode is connected to a driving module of a second touch controller.

[0005] The demodulation unit is used to receive a first sensing signal transmitted by the first receiving electrode, and the first sensing signal is generated based on the first driving signal transmitted by the driving module to the first transmitting electrode. The demodulation unit is also used to demodulate the first sensing signal to obtain a first demodulation signal. The autocorrelator is used to reset the first frequency divider according to the first demodulation signal to synchronize with the second frequency divider of the second touch controller. The demodulation unit is also used to receive a second sensing signal transmitted by the first receiving electrode, and the second sensing signal is generated based on the second driving signal transmitted by the driving module to the first transmitting electrode. The demodulation unit is also used to demodulate the second sensing signal multiple times to obtain second demodulation signals of multiple frequencies, and the second demodulation signals of multiple frequencies are used to correct the frequency and phase of the first clock unit to synchronize with the second clock unit of the second touch controller.

[0006] In an exemplary embodiment, the second demodulated signals of the multiple frequencies correspond to a normalized ratio, the normalized ratio is used to determine a frequency error between the first clock unit and the second clock unit, and the frequency error is used to correct the frequency and the phase of the first clock unit.

[0007] In an exemplary embodiment, the first touch controller is connected to the second touch controller via a communication interface; the demodulation unit is used to execute the reception of the first sensing signal transmitted by the first receiving electrode in response to a start-up instruction transmitted by the second touch controller received via the communication interface.

[0008] In an exemplary embodiment, the demodulation unit is also connected to the second receiving electrode of the touch sensor, the second receiving electrode is coupled to the second transmitting electrode of the touch sensor, and the second transmitting electrode is connected to the driving module of the second touch controller; the demodulation unit is also used to receive multiple data bits transmitted by the second receiving electrode, the multiple data bits are transmitted by the driving module through the second transmitting electrode, the multiple data bits are obtained through phase modulation, and the multiple data bits carry communication data; the demodulation unit is also used to demodulate the multiple data bits to obtain the communication data.

[0009] In an exemplary embodiment, the second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor, and the second receiving electrode and the second transmitting electrode have matching signal levels.

[0010] In a second aspect, a synchronization method is provided, the method comprising:

[0011] receiving, by a demodulation unit, a first sensing signal transmitted by a first receiving electrode of a touch sensor, where the first sensing signal is generated based on a first driving signal transmitted by a driving module of a second touch controller to a first transmitting electrode of the touch sensor;

[0012] Demodulating the first sensing signal by the demodulation unit to obtain a first demodulated signal;

[0013] Resetting a first frequency divider of a first touch controller according to the first demodulated signal through an autocorrelator to synchronize with a second frequency divider of the second touch controller;

[0014] receiving, by the demodulation unit, a second sensing signal transmitted by the first receiving electrode, wherein the second sensing signal is generated based on a second driving signal transmitted by the driving module to the first transmitting electrode;

[0015] The demodulation unit demodulates the second sensing signal multiple times to obtain second demodulation signals with multiple frequencies, and the second demodulation signals with multiple frequencies are used to correct the frequency and phase of the first clock unit of the first touch controller to synchronize with the second clock unit of the second touch controller.

[0016] In an exemplary embodiment, the second demodulated signals of the multiple frequencies correspond to a normalized ratio, the normalized ratio is used to determine a frequency error between the first clock unit and the second clock unit, and the frequency error is used to correct the frequency and the phase of the first clock unit.

[0017] In an exemplary embodiment, the first sensing signal transmitted by the first receiving electrode of the touch sensor is received through the demodulation unit, including: in response to receiving a start instruction transmitted by the second touch controller through the communication interface, the demodulation unit executes the first sensing signal transmitted by the first receiving electrode of the touch sensor.

[0018] In an exemplary embodiment, the method further includes: receiving, by the demodulation unit, a plurality of data bits transmitted by the second receiving electrode, wherein the plurality of data bits are transmitted by the driving module through the second transmitting electrode, the plurality of data bits are obtained by phase modulation, and the plurality of data bits carry communication data; and demodulating the plurality of data bits by the demodulation unit to obtain the communication data.

[0019] In an exemplary embodiment, the second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor, and the second receiving electrode and the second transmitting electrode have matching signal levels.

[0020] According to a third aspect, a chip is provided, wherein the chip includes the first touch controller provided by the first aspect or any exemplary embodiment of the first aspect.

[0021] According to a fourth aspect, an electronic device is provided. The electronic device includes a touch sensor, a first touch controller provided by the first aspect or any exemplary embodiment of the first aspect, and a second touch controller.

[0022] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0023] The embodiment of the present application realizes the reset of the frequency divider through the automatic correlator, avoids the misalignment of the frequency dividers in different touch controllers, and ensures the synchronization of the frequency dividers in different touch controllers. The embodiment of the present application also obtains the second demodulation signal of multiple frequencies through demodulation, thereby ensuring the clock synchronization in different touch controllers. As a result, the synchronization between different touch controllers is strong, which is suitable for the scenario of cascading different touch sensors and suitable for use with larger screens. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 is a schematic diagram of a touch sensor and a touch controller in a related technology provided by an embodiment of the present application;

[0026] Figure 2 is a waveform diagram of a driving signal transmitted to an emitting electrode in a related technology provided in an embodiment of the present application;

[0027] Figure 3 is a schematic diagram of a touch sensor and a touch controller in another related technology provided by an embodiment of the present application;

[0028] Figure 4 is a connection diagram of a touch sensor and a touch controller in another related technology provided by an embodiment of the present application;

[0029] Figure 5 is a connection diagram of a touch sensor and a touch controller in another related technology provided by an embodiment of the present application;

[0030] Figure 6 is a connection diagram of a touch sensor and a touch controller provided in an embodiment of the present application;

[0031] Figure 7 is another schematic diagram of connection between a touch sensor and a touch controller provided in an embodiment of the present application;

[0032] Figure 8 This is a connection diagram of another touch sensor and touch controller provided in an embodiment of the present application;

[0033] Fig. 9 is a schematic diagram of a demodulation process provided by an embodiment of the present application;

[0034] Fig.10is a connection diagram of another touch sensor and a touch controller provided in an embodiment of the present application;

[0035] Fig.11 is a schematic diagram of a demodulation response provided in an embodiment of the present application;

[0036] Fig.12 It is a flowchart of a synchronization method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0038] With the development of touch technology, touch sensors are integrated into the display modules of many devices, such as mobile phones, laptops, and smart car devices. Touch sensors are, for example, projected capacitive touch (PCAP) sensors. Among them, the PCAP sensor includes at least one group of transmitting (Transmit, TX) electrodes and receiving (Receive, RX) electrodes, and each group of transmitting electrodes and receiving electrodes are orthogonal and mutually coupled.

[0039] At the intersection of orthogonal transmitting and receiving electrodes, there is mutual capacitance. When a user's finger touches the touch sensor, the above mutual capacitance can be changed. In addition, there is self-capacitance between each transmitting electrode and the system reference, and there is self-capacitance between each receiving electrode and the system reference, which can be designated as ground. When a user's finger touches the touch sensor, the above self-capacitance can also be changed.

[0040] The touch sensor is connected to a touch controller, which can measure mutual capacitance or self-capacitance and determine the position of an object near the touch sensor according to the change in mutual capacitance or self-capacitance. The object is, for example, the user's finger.

[0041] See also Figure 1 , Figure 1 An exemplary touch sensor and touch controller are shown for measuring the mutual capacitance of a pair of coupled transmitting electrodes and receiving electrodes in the touch sensor. Figure 1 In the present invention, the touch controller includes a signal generator, a driver, a first pad, a second pad, an amplifier, a demodulator, a low-pass filter (LPF) and a memory.

[0042] The signal generator generates a signal and transmits a clock signal to the driver. The driver is connected to the transmitting electrode through the first pad and transmits a driving signal to the transmitting electrode. Accordingly, a sensing signal is generated on the receiving electrode. The amplifier amplifies the sensing signal, the demodulator demodulates the amplified sensing signal according to the signal generated by the signal generator, the LPF filters the demodulated signal, and the filtered signal is stored in the memory. The processor can obtain the stored filtered signal from the memory and calculate the mutual capacitance based on the obtained signal.

[0043] The second pad, amplifier, demodulator and LPF corresponding to a receiving electrode are recorded as a receiver channel. In the time division multiplexing (TDM) scheme, the touch controller transmits a driving signal to one transmitting electrode at a time, and measures all the receiver channels corresponding to this transmitting electrode. In the code division multiplexing (CDM) scheme, the touch controller transmits a driving signal to multiple transmitting electrodes at a time, and the driving signal transmitted to multiple transmitting electrodes is modulated by a carrier coding mode of 0 and 180°, and all the receiver channels corresponding to multiple transmitting electrodes are measured.

[0044] In the CDM scheme, the filtered signal output by the LPF in the receiver channel can be sampled, and the sampling result (for example, a matrix) is multiplied by the inverse matrix of the coding matrix to obtain a signal proportional to the mutual capacitance. The carrier coding mode of 0 and 180° can be implemented based on Hadamard code, and an example of Hadamard code is as follows.

[0045]

[0046] Accordingly, the waveform of the driving signal transmitted by the touch controller to the plurality of transmitting electrodes is as follows: Figure 2 As shown. The four waveforms are transmitted by the touch controller to the transmitting electrode N to the transmitting electrode N+3 respectively, and each waveform includes a portion corresponding to code segment 0, code segment 1, code segment 2 and code segment 3. From left to right, the four elements in a row of the Hadamard code correspond to code segment 0, code segment 1, code segment 2 and code segment 3 respectively.

[0047] See also Figure 3 , Figure 3 An exemplary touch sensor and touch controller are shown for measuring self-capacitance in a touch sensor. Figure 3In the embodiment, the touch controller includes a signal generator, a first driver, a second driver, a first pad, a second pad, a resistor, an amplifier, a demodulator, an LPF and a memory. In the process of measuring the self-capacitance, a voltage signal can be applied to the transmitting electrode of the touch sensor to measure the voltage difference across the resistor. The voltage difference can be used to measure the current signal converted by the resistor, and then the self-capacitance can be calculated by the measured current signal. When applying the voltage signal, the voltage signal can be applied to all the transmitting electrodes of the touch sensor to avoid the influence of mutual capacitance when measuring the self-capacitance. Optionally, the above-mentioned demodulator is a narrowband demodulator.

[0048] The signal generator generates a voltage signal and transmits the voltage signal to both the first driver and the second driver. The first driver transmits a driving signal to the transmitting electrode through the first pad. The second driver transmits a voltage signal to the resistor, and the resistor converts the voltage signal into a current signal. There is a voltage difference between the two ends of the resistor, and the voltage difference can be used to measure the current signal converted by the resistor, and then used to measure the self-capacitance.

[0049] Next, the amplifier amplifies the voltage difference, and the amplified voltage difference is transmitted to the demodulator. The demodulator demodulates the amplified voltage difference according to the voltage signal generated by the signal generator. The LPF filters the demodulated signal, and the filtered signal can be stored in the memory. The processor can obtain the stored filtered signal from the memory and calculate the self-capacitance based on the obtained signal.

[0050] In the related art, mutual capacitance measurement can be achieved by mixing analog circuits and digital circuits. Figure 4 As shown, the touch controller includes a common clock, a frequency divider, a digitally controlled oscillator (NCO), a code segment counter, a CDM code memory, a modulator, a buffer, a first pad, a second pad, an amplifier, a band-pass filter (BPF), an analog digital converter (ADC), a demodulator, an LPF, a sampler, a multiplier and a memory. The steps of measuring mutual capacitance include the following steps 1 to 8.

[0051] Step 1: The frequency divider divides the common clock, and the NCO generates a carrier signal based on the divided signal at a certain frequency.

[0052] Step 2: The code segment counter is incremented by multiples of the common clock, and the obtained count is used to track the index of the CDM code so that the modulator can correctly modulate the carrier signal in each code segment of the CDM code.

[0053] Step 3: The modulated carrier signal is transmitted to the transmitting electrode of the touch sensor through the buffer.

[0054] Step 4: The modulated carrier signal passes through the touch sensor and reaches the receiving electrode.

[0055] Step 5, the amplifier amplifies the analog signal from the receiving electrode, the BPF filters the amplified analog signal, the ADC samples the filtered analog signal, and the ADC works according to the frequency division of the common clock.

[0056] Step 6: The demodulator demodulates the digital signal output by the ADC according to the signal output by the NCO, wherein the frequency of the NCO matches the carrier signal to transfer the CDM code component in the digital signal to the baseband.

[0057] Step 7, LPF performs low-pass filtering on the baseband signal, and the sampler samples the filtered baseband signal before the code segment conversion. The sampler is controlled by a frequency divider that matches the code segment counter, but there may be a phase offset, and the value of the phase offset is adapted to the system delay.

[0058] Step 8: The signal sampled by the sampler is a matrix, and each sampled value in the matrix corresponds to the difference between each receiving electrode in each code segment. The matrix is ​​multiplied by the inverse matrix of the CDM code to generate a result matrix, which includes the signal components corresponding to each intersecting transmitting electrode and receiving electrode, and the result matrix is ​​stored in the memory. The processor can calculate the touch position based on the result matrix.

[0059] Figure 4 The touch sensor and touch controller shown can also be used in the self-capacitance measurement scheme in the related art or the scheme of measuring mutual capacitance based on an active stylus, which will not be repeated here. In the scheme of measuring mutual capacitance based on an active stylus, the touch controller can have two concurrent complete IQ demodulators (such as the above-mentioned receiver channels), and the IQ demodulator is used to complete the above-mentioned steps 6 and 7, where I represents in-phase and Q represents quadrature.

[0060] Large screens (e.g., 6.1-inch mobile phone screens) can use a single IC (integrated circuit) as a touch controller. As mentioned above, the touch controller can have multiple receiver channels to quickly complete all mutual capacitance and self-capacitance measurements to reduce power consumption and increase the number of measurements completed within a specified time period, which is the reporting rate. The higher the reporting rate, the better, because the higher the reporting rate, the smaller the delay in providing a response to the user, and even if the objects around the touch sensor (e.g., the user's fingers) have a high movement speed, accurate reporting can be achieved. For large screens, at least two touch controllers can also be used, i.e., cascaded touch controllers. In this case, the measurement of mutual capacitance and self-capacitance requires at least two touch controllers to coordinate with each other.

[0061] See also Figure 5 , Figure 5 A touch sensor corresponding to a single touch controller is shown, the touch sensor comprising 7 columns of sensor lines (ie, TX electrodes) and 15 rows of sensor lines (ie, RX electrodes), all connected to the single touch controller. It should be understood that Figure 5 The illustrated situation is only an example, and the touch sensor may include more rows and columns of sensor lines, for example, may include 18 TX electrodes and 38 RX electrodes.

[0062] See also Figure 6 , Figure 6 A touch sensor corresponding to two touch controllers (ie, a first touch controller and a second touch controller) is shown. The touch sensor has 14 TX electrodes and 30 RX electrodes, which are connected to the first touch controller or the second touch controller respectively. Figure 6 The touch sensor operable range is shown as Figure 5 4 times the operable range of the touch sensor shown.

[0063] When two touch controllers are used, the two touch controllers need to coordinate with each other, and the coordination depends on the synchronization of the common clock. In addition, the divider used to divide the common clock also needs to be synchronized. For example, see Figure 7 , the touch sensor is divided into four quadrants, namely quadrant 11, quadrant 21, quadrant 12 and quadrant 22. For quadrant 21 and quadrant 12, modulation and demodulation are performed in different touch controllers, thus requiring synchronization of clocks and frequency dividers of different touch controllers.

[0064] In the related art, the synchronization problem is solved by adding a hardware signal between two touch controllers. For example, a PLL (phase locked loop) or other circuit dedicated to synchronization is used in each touch controller, the PLL is linked to a common reference, and a synchronization signal is sent from one touch controller to another touch controller to ensure the synchronization of the clock and the divider. However, this method will increase the cost of the touch controller.

[0065] For example, the number of pins on the touch controller is proportional to the packaging cost, and the connection between different devices will also increase the cost, especially when the physical distance between different devices is far and they need to be connected through cables and connectors. In addition, the PLL or other circuits dedicated to synchronization also require costs, and the use of PLL or other circuits dedicated to synchronization will increase the area of ​​the touch controller. Since the area is proportional to the material and production costs, it leads to an increase in cost. In addition, adding PLL or other circuits dedicated to synchronization will also increase development costs. Considering that touch controllers are more sensitive to cost issues, these additional costs are not desirable.

[0066] In this regard, Figure 8 As shown, an embodiment of the present application provides a touch controller. The touch controller is a first touch controller 1, which includes a first frequency divider 11, an auto-correlator 12, a first clock unit 13 and a demodulation unit 14. The first frequency divider 11 is connected to the auto-correlator 12, the first clock unit 13 and the demodulation unit 14 respectively. The demodulation unit 14 is also connected to the auto-correlator 12 and the first receiving electrode 31 of the touch sensor 3 respectively. The first receiving electrode 31 is coupled to the first transmitting electrode 32 of the touch sensor 3, and the first transmitting electrode 32 is connected to the driving module of the second touch controller 2.

[0067] The demodulation unit 14 is used to receive a first sensing signal transmitted by the first receiving electrode 31, and the first sensing signal is generated based on the first driving signal transmitted by the driving module to the first transmitting electrode 32. The demodulation unit 14 is used to demodulate the first sensing signal to obtain a first demodulation signal. The autocorrelator 12 is used to reset the first frequency divider 11 according to the first demodulation signal to synchronize with the second frequency divider of the second touch controller 2. The demodulation unit 14 is also used to receive a second sensing signal transmitted by the first receiving electrode 31, and the second sensing signal is generated based on the second driving signal transmitted by the driving module to the first transmitting electrode 32. The demodulation unit 14 is also used to demodulate the second sensing signal multiple times to obtain second demodulation signals of multiple frequencies, and the second demodulation signals of multiple frequencies are used to correct the frequency and phase of the first clock unit 13 to synchronize with the second clock unit of the second touch controller 2.

[0068] During the synchronization process between the first frequency divider 11 of the first touch controller 1 and the second frequency divider of the second touch controller 2, the driving module of the second touch controller 2 transmits a first driving signal to the first transmitting electrode 32 in the touch sensor 3. The first driving signal can be considered as a carrier signal pulse string, or a timing pulse string. Correspondingly, the first receiving electrode 31 coupled to the first transmitting electrode 32 in the touch sensor 3 generates a first sensing signal, and the first receiving electrode 31 transmits the first sensing signal to the demodulation unit 14. The demodulation unit 14 can demodulate the first sensing signal to obtain a first demodulation signal, and transmit the first demodulation signal to the autocorrelator 12, and the autocorrelator 12 resets the first frequency divider 11 according to the first demodulation signal.

[0069] In addition to the first receiving electrode 31 coupled to the first transmitting electrode 32, the touch sensor 3 also has a third receiving electrode coupled to the first transmitting electrode 32, and the third receiving electrode is coupled to the demodulation unit 'of the second touch controller 2 itself. Figure 7 Taking the shown situation as an example, the first transmitting electrode 32 is located in quadrant 11 and quadrant 12. In quadrant 12, the first transmitting electrode 32 is coupled with the first receiving electrode 31 (the demodulation unit 14 connected to the first touch controller 1). In quadrant 11, the first transmitting electrode 32 is coupled with the third receiving electrode (the demodulation unit 'connected to the second touch controller 2).

[0070] In the embodiment of the present application, the second touch controller 2 may include a second frequency divider, an autocorrelator ', a second clock unit and a demodulation unit '. The connection relationship and functions between these components can be seen in Figure 8 The connection relationship and functions between the components included in the first touch controller 1 are not described in detail here. Of course, the first touch controller 1 may also include a driving module ', and the functions of the driving module ' can refer to the functions of the driving module included in the second touch controller 2, which are also not described in detail here.

[0071] Based on the description in the previous paragraph, it can be known that after the driving module of the second touch controller 2 transmits the first driving signal to the first transmitting electrode 32, the third receiving electrode also generates the first sensing signal ', and the third receiving electrode transmits the first sensing signal ' to the demodulation unit ' of the second touch controller 2, and the demodulation unit ' of the second touch controller 2 demodulates the first sensing signal ' to obtain the first demodulation signal ', and transmits the first demodulation signal ' to the autocorrelator ' of the second touch controller 2, then the autocorrelator ' of the second touch controller 2 resets the second frequency divider according to the first demodulation signal '. As a result, the first frequency divider 11 and the second frequency divider are reset based on the demodulation signal (including the first demodulation signal and the first demodulation signal ') corresponding to the same driving signal, thereby achieving synchronization between the first frequency divider 11 and the second frequency divider.

[0072] In the related art, the autocorrelator 12 is applied to the one-way stylus protocol, and the functions of the autocorrelator 12 include: detecting the time when the stylus transmits a pulse string. In this one-way stylus protocol, the stylus cannot be synchronized with the touch controller, so the touch controller needs to be synchronized with the stylus, for example, the time of the touch controller is consistent with the time of the stylus, so the above-mentioned autocorrelator 12 is used, and the time when the stylus transmits a pulse string is detected by the autocorrelator 12, so that the time of the touch controller is consistent with the time of the stylus. In the embodiment of the present application, by setting the connection relationship between the demodulation unit 14, the autocorrelator 12 and the first frequency divider 11, the autocorrelator 12 can reset the first frequency divider 11, thereby realizing the synchronization of the frequency dividers between different touch controllers (including the first touch controller 1 and the second touch controller 2) based on the autocorrelator 12, and ensuring the synchronization of different touch controllers.

[0073] In addition, during the synchronization process between the first clock unit 13 of the first touch controller 1 and the second clock unit of the second touch controller 2, the driving module of the second touch controller 2 transmits a second driving signal to the first transmitting electrode 32 in the touch sensor 3. The second driving signal can be considered as a synchronous pulse train. For example, the second driving signal can be Fig. 9 As shown in the synchronization pulse string 1 (Sync 1) or the synchronization pulse string 2 (Sync 2), the sending process of the second driving signal can be located before the mutual capacitance measurement process (i.e., the mutual measurement process). Accordingly, the first receiving electrode 31 coupled to the first transmitting electrode 32 in the touch sensor 3 generates a second sensing signal accordingly, and the first receiving electrode 31 transmits the second sensing signal to the demodulation unit 14. The demodulation unit 14 can demodulate the second sensing signal multiple times (for example, at least twice), using a different frequency for each demodulation, to obtain a second demodulation signal of multiple frequencies, and the second demodulation signal of multiple frequencies is used to correct the frequency and phase of the first clock unit 13 to synchronize with the second clock unit of the second touch controller 2. Exemplarily, the processor ( Figure 8 (not shown) corrects the frequency and phase of the first clock unit 13 according to the second demodulated signal of multiple frequencies.

[0074] In the related art, the demodulation unit 14 is applied to the unidirectional stylus protocol, and the role of the demodulation unit 14 includes: demodulating multiple carrier signals on a specified receiver channel. For example, the stylus has two transmitting antennas, which are separated on the body of the stylus and work at different orthogonal frequencies. The demodulation unit 14 demodulates the carrier signals transmitted by the two transmitting antennas, thereby determining the spatial positions of the two transmitting antennas relative to the touch sensor 3, that is, obtaining two different spatial positions, and the angle of the stylus relative to the touch sensor 3 can be determined according to the two different spatial positions. In the embodiment of the present application, by adopting the demodulation unit 14, the second sensing signal can be demodulated multiple times, and the obtained second demodulation signals of multiple frequencies can be used to correct the frequency and phase of the first clock unit 13, so that the clock synchronization between different touch controllers (including the first touch controller 1 and the second touch controller 2) is realized based on the demodulation unit 14, the synchronization of different touch controllers is ensured, and the different touch controllers are fully coupled and matched to adapt to the slight changes in the transmission and demodulation process.

[0075] It can be seen from the above description that in the embodiment of the present application, for a cascade system with multiple touch controllers, without setting up an external interface and / or additional circuit (such as PLL), the synchronization of the dividers and the clocks between different touch controllers are achieved, which is conducive to further achieving modulation synchronization and demodulation synchronization.

[0076] Next, combine Fig.10 The structure of the first touch controller 1 is described in detail. The structure of the second touch controller 2 may be the same as that of the first touch controller 1, and will not be described in detail.

[0077] The driving module of the first touch controller 1 includes a first sub-frequency divider, a second sub-frequency divider, a first sub-clock unit, a first NCO, a code segment counter, a CDM code memory, a driver, a first amplifier and a first pad. The connection relationship between these components is as follows: Fig.10 As shown, the first pad is connected to the transmitting electrode of the touch sensor 3.

[0078] The first sub-clock unit provides a first clock signal, the first sub-divider divides the first clock signal, the first NCO generates a first carrier signal according to the divided signal, the second sub-divider divides the first clock signal, the code segment counter counts according to the divided signal, and the obtained count is stored in the CDM code memory, the driver generates a drive signal according to the first carrier signal and the count stored in the CDM code memory, the first amplifier amplifies the drive signal, and the amplified drive signal is transmitted to the transmitting electrode of the touch sensor 3 through the first pad.

[0079] The sensing module of the first touch controller 1 includes a second pad connected to a receiving electrode of the touch sensor 3 (for example, the first receiving electrode 31 described above), a second amplifier, a BPF, an ADC, a mixer (also referred to as a demodulator), a second NCO, an LPF, an autocorrelator 12, a second sub-clock unit, a third sub-frequency divider, a fourth sub-frequency divider, a sampler, and a multiplier. The connection relationship between these components is as follows: Fig.10 The mixer, the second NCO and the LPF form a demodulation subunit, and the demodulation unit 14 may include at least one demodulation subunit. Fig.10 The one demodulation subunit shown in FIG. 1 is only an example.

[0080] The above-mentioned first sensing signal and second sensing signal can be transmitted to the second amplifier through the second pad. The second amplifier amplifies the first sensing signal (or the second sensing signal) to obtain an amplified sensing signal. The BPF filters the amplified sensing signal to obtain a filtered sensing signal. The filtered sensing signal is an analog signal, and the ADC converts the analog signal into a digital signal.

[0081] For the first sensing signal, the mixer receives the digital signal corresponding to the first sensing signal, and the second sub-clock unit provides the second clock signal, the third sub-frequency divider divides the second clock signal, the second NCO generates a second carrier signal according to the divided signal, and the mixer demodulates the digital signal corresponding to the first sensing signal according to the second carrier signal to obtain the above-mentioned first demodulated signal. The mixer transmits the first demodulated signal to the LPF, and the LPF filters the first demodulated signal to obtain the first filtered signal.

[0082] On the one hand, the LPF transmits the first filtered signal to the sampler. In addition, the fourth sub-divider divides the second clock signal provided by the second sub-clock unit, the sampler samples the first filtered signal according to the divided signal to obtain a first sampling matrix, the multiplier performs multiplication calculation on the first sampling matrix to obtain a first result matrix, the first result matrix can be stored in the memory, so that the processor can read the first result matrix from the memory, and the processor can determine the touch position according to the first result matrix.

[0083] On the other hand, the LPF transmits the first filtering signal to the autocorrelator 12, and the autocorrelator 12 resets the third sub-frequency divider and the fourth sub-frequency divider according to the first filtering signal. The first frequency divider 11 may include the third sub-frequency divider and the fourth sub-frequency divider. Exemplarily, the first frequency divider 11 may also include the first sub-frequency divider and the second sub-frequency divider, that is, the autocorrelator 12 may also reset the first sub-frequency divider and the second sub-frequency divider according to the first filtering signal, except that Fig.10 The connection relationship between the autocorrelator 12 and the first sub-frequency divider is not shown, and the connection relationship between the autocorrelator 12 and the second sub-frequency divider is not shown.

[0084] Next, the process of resetting the first frequency divider 11 according to the first filter signal by the autocorrelator 12 is described. After the LPF transmits the first filter signal to the autocorrelator 12, the autocorrelator 12 can accurately detect the time when the LPF transmits the first filter signal. Once the autocorrelator 12 detects the first filter signal, it transmits a valid signal to the first frequency divider 11.

[0085] The first frequency divider 11 includes a counter, and the first frequency divider 11 can divide the input clock signal (i.e., the above-mentioned second clock signal) through the counter. Specifically, when the input clock signal reaches the first frequency divider 11, the counter starts counting. When the count value of the counter reaches a certain value, the counter outputs a flip signal, thereby changing the state of the output clock signal (i.e., the above-mentioned divided signal) to achieve a frequency division effect. The embodiment of the present application does not limit the above-mentioned certain value, and the value of the certain value can be determined according to actual needs. For example, after each rising edge of the input clock signal reaches the first frequency divider 11, the first frequency divider 11 counts once. When the value of the certain value is 2, when every 2 rising edges of the input clock signal reach the first frequency divider 11, the counter outputs a flip signal, that is, the output clock signal flips once.

[0086] The above paragraph explains the principle of frequency division by the first frequency divider 11. Based on this principle, resetting the first frequency divider 11 refers to resetting the counter inside the first frequency divider 11. That is, after the autocorrelator 12 transmits a valid signal to the first frequency divider 11, the first frequency divider 11 receives the valid signal and resets the counter inside the first frequency divider 11 according to the valid signal. Optionally, resetting the counter inside the first frequency divider 11 refers to resetting the counter to an initial value, such as returning the counter to zero.

[0087] As mentioned above, the first frequency divider 11 may include: a first sub-frequency divider, a second sub-frequency divider, a third sub-frequency divider and a fourth sub-frequency divider. The autocorrelator 12 resets the first frequency divider 11 according to the first filtered signal, which means that the autocorrelator 12 resets the counters inside the first sub-frequency divider, the second sub-frequency divider, the third sub-frequency divider and the fourth sub-frequency divider respectively according to the first filtered signal.

[0088] Among them, the automatic correlator 12 transmits a valid signal to the first sub-frequency divider, the first sub-frequency divider receives the valid signal, and resets the counter inside the first sub-frequency divider according to the valid signal. The automatic correlator 12 transmits a valid signal to the second sub-frequency divider, the second sub-frequency divider receives the valid signal, and resets the counter inside the second sub-frequency divider according to the valid signal. The automatic correlator 12 transmits a valid signal to the third sub-frequency divider, the third sub-frequency divider receives the valid signal, and resets the counter inside the third sub-frequency divider according to the valid signal. The automatic correlator 12 transmits a valid signal to the fourth sub-frequency divider, the fourth sub-frequency divider receives the valid signal, and resets the counter inside the fourth sub-frequency divider according to the valid signal.

[0089] Therefore, in the first touch controller 1, the autocorrelator 12 resets the first frequency divider 11 according to the first filtered signal (obtained based on the first demodulated signal), and the various sub-frequency dividers included in the first frequency divider 11 can synchronously restart counting, flip the signal and change the state of the output clock signal.

[0090] Based on the same principle, in the second touch controller 2, the autocorrelator ' can also reset the second frequency divider according to the first filter signal ' (obtained based on the first demodulation signal '), then the various sub-frequency dividers included in the second frequency divider can also synchronously restart counting, flip signals and change the state of the output clock signal. Since the first demodulation signal and the first demodulation signal ' are demodulation signals corresponding to the same drive signal, the various sub-frequency dividers included in the first frequency divider 11 and the various sub-frequency dividers included in the second frequency divider can synchronously restart counting, flip signals and change the state of the output clock signal, thereby achieving synchronization between the first frequency divider 11 and the second frequency divider, and then ensuring the consistency between the first touch controller 1 and the second touch controller 2. As a result, when the modulation process and the demodulation process are carried out in different touch controllers (i.e., the first touch controller 1 and the second touch controller 2), the modulation process and the demodulation process can still be correctly completed.

[0091] In an exemplary embodiment, the first touch controller 1 is connected to the second touch controller 2 via a communication interface. The demodulation unit 14 is used to receive the first sensing signal transmitted by the first receiving electrode 31 in response to the start-up instruction transmitted by the second touch controller 2 received via the communication interface. If the first touch controller 1 is required to continuously receive and demodulate the sensing signal (such as the first sensing signal mentioned above), more power will be consumed, so preliminary synchronization can be performed through the communication interface, that is, the second touch controller 2 transmits the start-up instruction to the first touch controller 1 through the communication interface, instructing the first touch controller 1 to start the demodulation unit 14 (or demodulation circuit) to prepare to receive and demodulate the first sensing signal generated based on the first drive signal. For the first touch controller 1, if the start-up instruction is not received, the components inside the first touch controller 1 can be powered off based on the power management scheme, and if the start-up instruction is received, the powered off components can be powered on to prepare to receive and demodulate the first sensing signal generated based on the first drive signal.

[0092] For the second sensing signal, the mixer receives a digital signal corresponding to the second sensing signal. In addition, the second sub-clock unit provides a second clock signal, and the third sub-frequency divider divides the second clock signal.

[0093] In one example, the demodulation unit 14 includes the above-mentioned multiple demodulation subunits, each of which corresponds to a frequency. Taking one demodulation subunit as an example, the second NCO in the demodulation subunit generates a third carrier signal according to the frequency-divided signal according to the corresponding frequency, and the mixer demodulates the digital signal corresponding to the second sensing signal according to the third carrier signal to obtain a second demodulation signal, and the multiple demodulation subunits obtain multiple second demodulation signals in total.

[0094] In another example, the demodulation unit 14 includes a demodulation subunit, and the demodulation subunit corresponds to multiple frequencies. For example, the second NCO in the demodulation subunit generates a fourth carrier signal according to the divided signal at frequency A, and the mixer demodulates the digital signal corresponding to the second sensing signal according to the fourth carrier signal to obtain a second demodulated signal. The second NCO in the demodulation subunit also generates a fifth carrier signal according to the divided signal at frequency B, and the mixer demodulates the digital signal corresponding to the second sensing signal according to the fifth carrier signal to obtain another second demodulated signal, and so on, a total of multiple second demodulated signals are obtained.

[0095] Regardless of which of the above examples, multiple second demodulated signals corresponding to multiple frequencies can be obtained. LPF filters the multiple second demodulated signals to obtain multiple second filtered signals. The second filtered signals are also called demodulation responses. LPF is also called a demodulation response filter. Taking multiple frequencies including frequency A and frequency B as an example, Fig.11 The demodulation responses corresponding to frequency A and frequency B are shown respectively.

[0096] The LPF transmits a plurality of second filtered signals to the autocorrelator 12, the sampler samples the plurality of second filtered signals to obtain a plurality of second sampling matrices, the multiplier multiplies the plurality of second sampling matrices to obtain a plurality of second result matrices, and the plurality of second result matrices are stored in the memory.

[0097] In an exemplary embodiment, the second demodulated signals of multiple frequencies (i.e., multiple second demodulated signals) correspond to a normalized ratio, which is used to determine the frequency error between the first clock unit 13 and the second clock unit, and the frequency error is used to correct the frequency and phase of the first clock unit 13.

[0098] Optionally, when the second demodulated signals of multiple frequencies refer to two second demodulated signals, the embodiment of the present application may determine the normalization ratio according to the following formula:

[0099]

[0100] Among them, A represents the demodulated signal (or the corresponding demodulated response) corresponding to frequency A, B represents the demodulated signal (or the corresponding demodulated response) corresponding to frequency B, N represents the normalization ratio, M represents the correction coefficient, the value of the correction coefficient is not limited in the embodiment of the present application, the value of the correction coefficient can be 1, and Error represents the frequency error.

[0101] Alternatively, in the case where the second demodulation signal of multiple frequencies refers to three or more second demodulation signals, the embodiment of the present application can determine the reference normalization ratio for every two second demodulation signals according to the above formula, and then perform weighted summation on all reference normalization ratios (the weights corresponding to different reference normalization ratios may be the same or different), and use the result of the weighted summation as the determined normalization ratio.

[0102] Optionally, after the processor determines the normalization ratio, it determines the frequency error between the first clock unit 13 and the second clock unit according to the normalization ratio, and corrects the frequency and phase of the first clock unit 13 according to the frequency error. Exemplarily, the frequency and phase of the second NCO can be configured according to the frequency error to correct the frequency and phase of the second sub-clock unit, and the first clock unit 13 can include the second sub-clock unit. Optionally, the first clock unit 13 can also include the first sub-clock unit, that is, the frequency and phase of the first NCO can also be configured according to the frequency error to correct the frequency and phase of the first sub-clock unit.

[0103] In an exemplary embodiment, the demodulation unit 14 is also connected to the second receiving electrode of the touch sensor 3, the second receiving electrode is coupled to the second transmitting electrode of the touch sensor 3, and the second transmitting electrode is connected to the driving module of the second touch controller 2. The demodulation unit 14 is also used to receive multiple data bits transmitted by the second receiving electrode, the multiple data bits are transmitted by the driving module through the second transmitting electrode, the multiple data bits are obtained by phase modulation, and the multiple data bits carry communication data. The demodulation unit 14 is also used to demodulate the multiple data bits to obtain communication data.

[0104] In the embodiment of the present application, since the frequency dividers and clocks of the first touch controller 1 and the second touch controller 2 are synchronized, there is a strong coupling relationship between the first touch controller 1 and the second touch controller 2, which can support more efficient encoding, such as a phase modulation scheme. Based on the phase modulation scheme, the first touch controller 1 and the second touch controller 2 can communicate directly through the electrodes coupled in the touch sensor 3, without setting a dedicated communication interface between the first touch controller 1 and the second touch controller 2, such as without setting an I 2 C (inter-integrated circuit, integrated circuit bus) or SPI (serial peripheral interface, serial peripheral interface) and other additional communication interfaces.

[0105] For example, the phase modulation scheme includes a phase modulation scheme with multiple phase increments. The second touch controller 2 modulates the multiple data bits to be transmitted according to this phase modulation scheme, carries the communication data to be exchanged through the multiple data bits, and transmits the multiple data bits to the first touch controller 1 through the driving module and the second transmitting electrode of the touch sensor 3. During the transmission process, each symbol can use the phase increment to transmit at least one of the multiple data bits. Correspondingly, the demodulation unit 14 in the first touch controller 1 can receive the multiple data bits through the second receiving electrode of the touch sensor 3, and demodulate the multiple data bits to obtain the communication data carried by the multiple data bits, so as to realize the communication between the first touch controller 1 and the second touch controller 2. As a result, it is possible for the first touch controller 1 and the second touch controller 2 to communicate directly through the electrodes coupled in the touch sensor 3.

[0106] In an exemplary embodiment, the second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor 3 , and the second receiving electrode and the second transmitting electrode have matching signal levels.

[0107] In the touch sensor 3, not all transmitting electrodes and receiving electrodes need to be used, and there may be unused transmitting electrodes and receiving electrodes in the touch sensor 3. In this regard, the embodiment of the present application can reuse the unused transmitting electrodes and receiving electrodes as the second transmitting electrodes and the second receiving electrodes mentioned above, thereby improving the electrode utilization rate of the touch sensor 3. The embodiment of the present application can also make the second receiving electrode and the second transmitting electrode have matching signal levels, for example, by matching the signal levels through a passive circuit, which is conducive to obtaining a better SNR (signal-to-noise ratio), and avoids the need for retransmission through the touch sensor 3 when the SNR is poor.

[0108] In summary, the embodiment of the present application achieves the reset of the frequency divider through the automatic correlator, avoids the misalignment of the frequency dividers in different touch controllers, and ensures the synchronization of the frequency dividers in different touch controllers. The embodiment of the present application also obtains the second demodulation signal of multiple frequencies by demodulation, determines the frequency error between the clocks in different touch controllers, which is conducive to correcting the frequency and phase of the clock, and ensures the frequency synchronization and phase synchronization of the clocks in different touch controllers. As a result, the synchronization between different touch controllers is strong, which is suitable for the scene of cascading different touch sensors, and is suitable for use with larger screens (or touch panels).

[0109] The embodiment of the present application also provides a synchronization method, which can be executed by the first touch controller mentioned above. Fig.12 As shown, the method includes but is not limited to steps 1201 to 1205.

[0110] Step 1201: receiving a first sensing signal transmitted by a first receiving electrode of a touch sensor through a demodulation unit, where the first sensing signal is generated based on a first driving signal transmitted by a driving module of a second touch controller to a first transmitting electrode of the touch sensor.

[0111] In an exemplary embodiment, receiving a first sensing signal transmitted by a first receiving electrode of a touch sensor through a demodulation unit includes: receiving a start instruction transmitted by a second touch controller through a communication interface through the demodulation unit, and executing the first sensing signal transmitted by the first receiving electrode of the touch sensor through the demodulation unit.

[0112] Step 1202: demodulate the first sensing signal by a demodulation unit to obtain a first demodulated signal.

[0113] Step 1203: reset a first frequency divider of the first touch controller according to the first demodulated signal through an autocorrelator to synchronize with a second frequency divider of the second touch controller.

[0114] Step 1204: receiving, by a demodulation unit, a second sensing signal transmitted by the first receiving electrode, where the second sensing signal is generated based on a second driving signal transmitted by the driving module to the first transmitting electrode.

[0115] Step 1205, demodulating the second sensing signal multiple times through the demodulation unit to obtain second demodulation signals with multiple frequencies, and the second demodulation signals with multiple frequencies are used to correct the frequency and phase of the first clock unit of the first touch controller to synchronize with the second clock unit of the second touch controller.

[0116] In an exemplary embodiment, the second demodulated signals of the plurality of frequencies correspond to a normalized ratio, the normalized ratio is used to determine a frequency error between the first clock unit and the second clock unit, and the frequency error is used to correct the frequency and phase of the first clock unit.

[0117] In an exemplary embodiment, the method also includes: receiving multiple data bits transmitted by the second receiving electrode through a demodulation unit, the multiple data bits are transmitted by the driving module through the second transmitting electrode, the multiple data bits are obtained through phase modulation, and the multiple data bits carry communication data; demodulating the multiple data bits through the demodulation unit to obtain communication data.

[0118] In an exemplary embodiment, the second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor, and the second receiving electrode and the second transmitting electrode have matching signal levels.

[0119] Fig.12 The method embodiment shown is similar to the above Figure 8 and Fig.10The first touch controller shown in the figure belongs to the same concept, therefore, the specific implementation method and technical effect corresponding to the embodiment of the method can be referred to above. Figure 8 and Fig.10 The corresponding instructions are not repeated here.

[0120] In an exemplary embodiment, the embodiment of the present application further provides a chip, and the chip includes the first touch controller described above.

[0121] Exemplarily, an embodiment of the present application further provides an electronic device, the electronic device comprising a touch sensor, a first touch controller and a second touch controller, the first touch controller and the second touch controller being connected to the touch sensor respectively. For example, the electronic device is a display device.

[0122] The terms "first", "second", etc. (if any) in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the above exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0123] It should be understood that the "plurality" mentioned in this article refers to two or more. "And / or" describes the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0124] The above description is only an exemplary embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A touch controller, characterized in that: The touch controller is a first touch controller, comprising a first frequency divider, an autocorrelator, a first clock unit and a demodulation unit, the first frequency divider is connected to the autocorrelator, the first clock unit and the demodulation unit respectively, the demodulation unit is further connected to the autocorrelator and a first receiving electrode of a touch sensor respectively, the first receiving electrode is coupled to a first transmitting electrode of the touch sensor, and the first transmitting electrode is connected to a driving module of a second touch controller; The demodulation unit is configured to receive a first sensing signal transmitted by the first receiving electrode, where the first sensing signal is generated based on a first driving signal transmitted by the driving module to the first transmitting electrode; The demodulation unit is further used to demodulate the first sensing signal to obtain a first demodulated signal; the autocorrelator being configured to reset the first frequency divider according to the first demodulated signal so as to be synchronized with the second frequency divider of the second touch controller; The demodulation unit is further used to receive a second sensing signal transmitted by the first receiving electrode, where the second sensing signal is generated based on a second driving signal transmitted by the driving module to the first transmitting electrode; The demodulation unit is also used to demodulate the second sensing signal multiple times to obtain second demodulation signals of multiple frequencies, and the second demodulation signals of multiple frequencies are used to correct the frequency and phase of the first clock unit to synchronize with the second clock unit of the second touch controller.

2. The method according to claim 1, characterized in that The second demodulated signals of the multiple frequencies correspond to a normalized ratio, and the normalized ratio is used to determine a frequency error between the first clock unit and the second clock unit, and the frequency error is used to correct the frequency and the phase of the first clock unit.

3. The touch controller according to claim 1 or 2, characterized in that: The first touch controller is connected to the second touch controller via a communication interface; The demodulation unit is configured to, in response to receiving a start instruction transmitted by the second touch controller through the communication interface, execute the receiving of the first sensing signal transmitted by the first receiving electrode.

4. The touch controller according to claim 1 or 2, characterized in that: The demodulation unit is also connected to a second receiving electrode of the touch sensor, the second receiving electrode is coupled to a second transmitting electrode of the touch sensor, and the second transmitting electrode is connected to a driving module of the second touch controller; The demodulation unit is further used to receive a plurality of data bits transmitted by the second receiving electrode, the plurality of data bits are transmitted by the driving module through the second transmitting electrode, the plurality of data bits are obtained by phase modulation, and the plurality of data bits carry communication data; The demodulation unit is further used to demodulate the multiple data bits to obtain the communication data.

5. The touch controller according to claim 4, characterized in that: The second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor, and the second receiving electrode and the second transmitting electrode have matching signal levels.

6. A synchronization method, characterized in that: The method comprises: receiving, by a demodulation unit, a first sensing signal transmitted by a first receiving electrode of a touch sensor, where the first sensing signal is generated based on a first driving signal transmitted by a driving module of a second touch controller to a first transmitting electrode of the touch sensor; Demodulating the first sensing signal by the demodulation unit to obtain a first demodulated signal; Resetting a first frequency divider of a first touch controller according to the first demodulated signal through an autocorrelator to synchronize with a second frequency divider of the second touch controller; receiving, by the demodulation unit, a second sensing signal transmitted by the first receiving electrode, wherein the second sensing signal is generated based on a second driving signal transmitted by the driving module to the first transmitting electrode; The demodulation unit demodulates the second sensing signal multiple times to obtain second demodulation signals with multiple frequencies, and the second demodulation signals with multiple frequencies are used to correct the frequency and phase of the first clock unit of the first touch controller to synchronize with the second clock unit of the second touch controller.

7. The method according to claim 6, characterized in that The second demodulated signals of the multiple frequencies correspond to a normalized ratio, and the normalized ratio is used to determine a frequency error between the first clock unit and the second clock unit, and the frequency error is used to correct the frequency and the phase of the first clock unit.

8. The method according to claim 6 or 7, characterized in that: The step of receiving, by a demodulation unit, a first sensing signal transmitted by a first receiving electrode of a touch sensor comprises: In response to receiving a start instruction transmitted by the second touch controller through the communication interface, the demodulation unit receives, through the demodulation unit, a first sensing signal transmitted by a first receiving electrode of the touch sensor.

9. The method according to claim 6 or 7, characterized in that: The method further comprises: Receiving, by the demodulation unit, a plurality of data bits transmitted by the second receiving electrode, the plurality of data bits being transmitted by the driving module through the second transmitting electrode, the plurality of data bits being obtained by phase modulation, and the plurality of data bits carrying communication data; The demodulation unit demodulates the multiple data bits to obtain the communication data.

10. The method according to claim 9, characterized in that The second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor, and the second receiving electrode and the second transmitting electrode have matching signal levels.

11. A chip, characterized in that: The chip includes the first touch controller described in any one of claims 1-5. 12 . An electronic device comprising a touch sensor, a first touch controller according to claim 1 , and a second touch controller.

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