Touch controller, synchronization method, chip and electronic device

Abstract

The application discloses a touch controller, a synchronization method, a chip and an electronic device, and belongs to the touch control technical field. Taking the touch controller as a first touch controller as an example, a demodulation unit is configured to receive and demodulate a first sensing signal transmitted by a first receiving electrode to obtain a first demodulation signal, and the first sensing signal is generated based on a first driving signal transmitted by a driving module to a first transmitting electrode. An automatic correlator is configured to reset a first frequency divider according to the first demodulation signal to synchronize with a second frequency divider of a second touch controller. The demodulation unit is further configured to receive and demodulate a second sensing signal transmitted by the first receiving electrode multiple times to obtain second demodulation signals of multiple frequencies, and the second demodulation signals of the multiple frequencies are used to correct the frequency and phase of a first clock unit to synchronize with a second clock unit of the second touch controller. The application realizes the synchronization between different touch controllers and is suitable for the scene of cascading different touch sensors.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the touch control field, in particular to a touch controller, a synchronization method, a chip and an electronic device. BACKGROUND

[0002] With the development of touch technology, many devices are equipped with touch sensors. The touch sensor includes coupled transmitting electrodes and receiving electrodes. In the case of a large area of the touch sensor, the coupled transmitting electrodes and receiving electrodes are connected to different touch controllers respectively, and thus synchronization between different touch controllers is needed. How to realize synchronization becomes a problem worthy of attention. SUMMARY

[0003] Embodiments of the present application provide a touch controller, a synchronization method, a chip and an electronic device, which can be used to realize 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, and the first touch controller includes a first frequency divider, an auto-correlator, a first clock unit and a demodulation unit. The first frequency divider is connected to the auto-correlator, the first clock unit and the demodulation unit respectively. The demodulation unit is also connected to the auto-correlator 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. The first transmitting electrode is connected to a driving module of a second touch controller.

[0005] The demodulation unit is configured to receive a first sensing signal transmitted by the first receiving electrode. 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 also configured to demodulate the first sensing signal to obtain a first demodulation signal. The auto-correlator is configured to reset the first frequency divider according to the first demodulation signal, so as to synchronize with a second frequency divider of the second touch controller. The demodulation unit is also configured to receive a second sensing signal transmitted by the first receiving electrode. 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 configured to demodulate the second sensing signal multiple times to obtain a plurality of frequency second demodulation signals. The plurality of frequency second demodulation signals are used to correct the frequency and phase of the first clock unit, so as to synchronize with a second clock unit of the second touch controller.

[0006] In an example embodiment, the second demodulation signals of the plurality of frequencies correspond to a normalized ratio, the normalized ratio being used to determine a frequency error between the first clock unit and the second clock unit, the frequency error being used to correct the frequency and the phase of the first clock unit.

[0007] In an example embodiment, the first touch controller and the second touch controller are connected through a communication interface; the demodulation unit is configured to receive the first sensing signal transmitted by the first receiving electrode in response to receiving a start instruction transmitted by the second touch controller through the communication interface.

[0008] In an example embodiment, the demodulation unit is further connected to a second receiving electrode of the touch sensor, the second receiving electrode being coupled to a second transmitting electrode of the touch sensor, the second transmitting electrode being connected to a driving module of the second touch controller; the demodulation unit is further configured to receive 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, the plurality of data bits carrying communication data; the demodulation unit is further configured to demodulate the plurality of data bits to obtain the communication data.

[0009] In an example embodiment, the second receiving electrode and the second transmitting electrode are unused electrodes included in the touch sensor, the second receiving electrode and the second transmitting electrode having 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, the first sensing signal being 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, by the demodulation unit, the first sensing signal to obtain a first demodulation signal;

[0013] resetting, by an auto-correlator, a first frequency divider of a first touch controller according to the first demodulation signal 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, the second sensing signal being generated based on a second driving signal transmitted by the driving module to the first transmitting electrode;

[0015] The second sensing signal is demodulated by the demodulation unit multiple times to obtain second demodulation signals of multiple frequencies, and the second demodulation signals of the multiple frequencies are used to correct a frequency and a phase of a first clock unit of the first touch controller to be synchronized with a second clock unit of the second touch controller.

[0016] In an example embodiment, the second demodulation 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.

[0017] In an example embodiment, the receiving, by the demodulation unit, of the first sensing signal transmitted by the first receiving electrode of the touch sensor includes: in response to receiving, by the communication interface, a start instruction transmitted by the second touch controller, performing, by the demodulation unit, the receiving, by the demodulation unit, of the first sensing signal transmitted by the first receiving electrode of the touch sensor.

[0018] In an example 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 a second transmitting electrode, the plurality of data bits are obtained by phase modulation, and the plurality of data bits carry communication data; demodulating, by the demodulation unit, the plurality of data bits to obtain the communication data.

[0019] In an example 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 matched signal levels.

[0020] In a third aspect, a chip is provided, and the chip includes the first touch controller provided in the first aspect or any example embodiment of the first aspect.

[0021] In a fourth aspect, an electronic device is provided, and the electronic device includes a touch sensor, a first touch controller provided in the first aspect or any example embodiment of the first aspect, and a second touch controller.

[0022] The technical solutions provided in the embodiments of the present application at least bring the following beneficial effects:

[0023] The embodiment of the present application realizes the reset of the frequency divider through the automatic correlator, avoids the misplacement of the frequency divider in different touch controllers, and ensures the synchronization of the frequency divider in different touch controllers. The embodiment of the present application also obtains the second demodulation signals of multiple frequencies through demodulation, and ensures the clock synchronization in different touch controllers. Therefore, 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 a screen with a large size. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[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 a transmitting electrode in a related technology provided by 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 schematic 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 schematic 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 schematic diagram of a touch sensor and a touch controller provided by an embodiment of the present application;

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

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

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

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

[0035] Figure 11 is a diagram of a demodulation response provided by an embodiment of the present application;

[0036] Figure 12 is a flow diagram of a synchronization method provided by an embodiment of the present application. DETAILED DESCRIPTION

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

[0038] With the development of touch technology, touch sensors are integrated into display modules of many devices, such as mobile phones, notebook computers and car smart devices. The touch sensor is, for example, a projected capacitive touch (PCAP) sensor. The PCAP sensor includes at least one set of transmit (TX) electrodes and receive (RX) electrodes, each set of transmit electrodes and receive electrodes being orthogonal and coupled to each other.

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

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

[0041] Referring to Figure 1 , Figure 1 An exemplary touch sensor and touch controller are shown for measuring mutual capacitance of a pair of coupled transmit electrodes and receive electrodes in a touch sensor. In Figure 1 , 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, the clock signal is transmitted to the driver, and the driver is connected to the transmitting electrode through the first bonding pad and transmits the driving signal to the transmitting electrode. Correspondingly, the 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 bonding pad corresponding to one receiving electrode, the amplifier, the demodulator and the LPF are recorded as one receiver channel. In a time division multiplexing (TDM) scheme, the touch controller transmits the driving signal to one transmitting electrode at a time, and measures all receiver channels corresponding to the one transmitting electrode. In a code division multiplexing (CDM) scheme, the touch controller transmits the driving signal to multiple transmitting electrodes at a time, the driving signals transmitted to the multiple transmitting electrodes are obtained by modulating the carrier encoding mode of 0 and 180°, and all receiver channels corresponding to the 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 encoding matrix to obtain a signal proportional to the mutual capacitance. The carrier encoding mode of 0 and 180° can be implemented based on Hadamard code. An example of Hadamard code is as follows.

[0045]

[0046] Correspondingly, the waveform of the driving signal transmitted by the touch controller to the multiple transmitting electrodes is as shown in Figure 2 The four waveforms are transmitted by the touch controller to the transmitting electrodes N to N+3 respectively, and each waveform includes the parts corresponding to the code segment 0, the code segment 1, the code segment 2 and the code segment 3. In order from left to right, the four elements in a row included in the Hadamard code correspond to the code segment 0, the code segment 1, the code segment 2 and the code segment 3 respectively.

[0047] Referring to Figure 3 , Figure 3 An exemplary touch sensor and touch controller for measuring self-capacitance in a touch sensor are shown in Figure 3In the process of measuring self-capacitance, a voltage signal can be applied on the transmitting electrodes of the touch sensor, and the voltage difference across the resistor can be measured, which can be used to measure the current signal converted by the resistor, and then the self-capacitance can be calculated based on the measured current signal. In the process of applying the voltage signal, the voltage signal can be commonly applied on all the transmitting electrodes of the touch sensor to avoid the influence of mutual-capacitance on the measurement of the self-capacitance. Optionally, the demodulator is a narrowband modulator.

[0048] The signal generator generates a voltage signal, which is transmitted to 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 the voltage signal to the resistor, and the resistor converts the voltage signal into a current signal. There is a voltage difference across the resistor, which can be used to measure the current signal converted by the resistor, and then used to measure the self-capacitance.

[0049] Then, the amplifier amplifies the voltage difference, and the amplified voltage difference is transmitted to the demodulator. The demodulator demodulates the amplified voltage difference based on 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, the measurement of mutual-capacitance can be realized by mixed use of analog circuit and digital circuit. As shown in FIG. 1, the touch controller includes a common clock, a frequency divider, a numerically 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. Figure 4 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.

[0051] Step 2, the code segment counter increments at a multiple of the common clock, and the obtained count is used to track the index of the CDM code, so that the modulator correctly modulates the carrier signal in each code segment of the CDM code.

[0052] Step 3, the modulator modulates the carrier signal in each code segment of the CDM code based on the index of the CDM code tracked by the code segment counter. Step 4, the buffer buffers the modulated carrier signal, and the first pad transmits the buffered modulated carrier signal to the transmitting electrode. Step 5, the amplifier amplifies the modulated carrier signal, and the amplified modulated carrier signal is transmitted to the BPF. Step 6, the BPF filters the amplified modulated carrier signal, and the filtered signal is transmitted to the ADC. Step 7, the ADC converts the filtered signal into a digital signal, and the demodulator demodulates the digital signal. Step 8, the LPF filters the demodulated signal, and the sampler samples the filtered signal. The multiplier multiplies the sampled signal with the CDM code, and the memory stores the multiplied signal.

[0053] Step 3, the modulated carrier signal is transmitted through a buffer to the transmit electrodes of the touch sensor.

[0054] Step 4, the modulated carrier signal passes through the touch sensor to the receive electrodes.

[0055] Step 5, an amplifier amplifies the analog signal from the receive electrodes, a BPF filters the amplified analog signal, and an ADC samples the filtered analog signal. The ADC operates according to a division of the common clock.

[0056] Step 6, a demodulator demodulates the digital signal output by the ADC according to a signal output by an NCO, where the frequency of the NCO matches the carrier signal to shift the CDM code components in the digital signal to baseband.

[0057] Step 7, an LPF low-pass filters the baseband signal, and a sampler samples the filtered baseband signal before code segment conversion. The sampler is controlled by a divider that matches the code segment counter but can have a phase offset, where the value of the phase offset is adapted to the system delay.

[0058] Step 8, the signal sampled by the sampler is a matrix, where each sample value in the matrix corresponds to a difference value of each receive electrode in each code segment. The matrix is multiplied by the inverse matrix of the CDM code to generate a result matrix, where the result matrix includes a signal component corresponding to each intersecting transmit electrode and receive electrode pair. The result matrix is stored in a memory. A processor can calculate a touch position based on the result matrix.

[0059] Figure 4 The illustrated touch sensor and touch controller can also be used in a self-capacitance measurement scheme or an active stylus based mutual capacitance measurement scheme in related technologies, which are not described here. In the active stylus based mutual capacitance measurement scheme, the touch controller can have two concurrent full IQ demodulators (e.g., the receiver channel described above) for completing steps 6 and 7 described above, where I stands for in-phase and Q stands for quadrature.

[0060] Large size screens (e.g. 6.1 inch mobile phone screens) can employ a single IC (integrated circuit) as a touch controller. As mentioned above, the touch controller can have multiple receiver channels, enabling fast measurements of all mutual and self capacitances, in order to reduce power consumption and increase the number of measurements within a specified time duration, which is the reporting rate. The higher the reporting rate, the less the delay in providing a response to the user, even if the objects (e.g. user's fingers) in the vicinity of the touch sensor have high movement speed. For large size screens, at least two touch controllers can be used, i.e. cascaded touch controllers, in which case the measurements of mutual and self capacitances require coordination between the at least two touch controllers.

[0061] Referring to Figure 5 , Figure 5 A touch sensor is shown corresponding to a single touch controller, comprising 7 columns of sensor lines (i.e. TX electrodes) and 15 rows of sensor lines (i.e. RX electrodes), all connected to the single touch controller. It is to be understood that Figure 5 The case shown is merely exemplary, and the touch sensor can comprise more columns and rows of sensor lines, e.g. 18 TX electrodes and 38 RX electrodes.

[0062] Referring to Figure 6 , Figure 6 A touch sensor is shown corresponding to two touch controllers (i.e. a first touch controller and a second touch controller), having 14 TX electrodes and 30 RX electrodes, connected to the first touch controller or the second touch controller, respectively. Figure 6 The operable range of the touch sensor shown is Figure 5 4 times the operable range of the touch sensor shown.

[0063] In the case of using two touch controllers, the two touch controllers need to be coordinated with each other, which relies on synchronization of the common clock, and in addition, the frequency dividers used to divide the common clock also need to be synchronized. For example, referring to Figure 7 The touch sensor is divided into 4 quadrants, i.e. quadrant 1 1, quadrant 2 1, quadrant 1 2 and quadrant 2 2. For quadrants 2 1 and 1 2, the modulation and demodulation are performed in different touch controllers, thus requiring synchronization of the clocks and frequency dividers of the 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 dedicated synchronization circuit 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 synchronization of the clock and frequency divider. However, this approach increases the cost of the touch controller.

[0065] For example, the number of pins on the touch controller is directly proportional to the packaging cost, and the connection between different devices also increases the cost, especially when the physical distance between different devices is far and the connection needs to be achieved through a cable and a connector, the cost will be further increased. Moreover, the PLL or other dedicated synchronization circuit itself also needs cost, and the use of the PLL or other dedicated synchronization circuit increases the area of the touch controller, since the area is directly proportional to the material and production cost, thus leading to an increase in cost. In addition, the addition of the PLL or other dedicated synchronization circuit also increases the development cost. Considering that the touch controller is sensitive to cost issues, these additional costs are undesirable.

[0066] To this end, as Figure 8 shown, an embodiment of the present application provides a touch controller. Wherein the touch controller is a first touch controller 1, the first touch controller 1 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 with the auto-correlator 12, the first clock unit 13, and the demodulation unit 14 respectively, the demodulation unit 14 is also connected with the auto-correlator 12 and a first receiving electrode 31 of a touch sensor 3 respectively, the first receiving electrode 31 is coupled with a first transmitting electrode 32 of the touch sensor 3, and the first transmitting electrode 32 is connected with a driving module of a second touch controller 2.

[0067] The demodulation unit 14 is configured to receive a first sensing signal transmitted by the first receiving electrode 31, the first sensing signal being generated based on a first driving signal transmitted by the driving module to the first transmitting electrode 32. The demodulation unit 14 is configured to demodulate the first sensing signal to obtain a first demodulation signal. The auto-correlator 12 is configured to reset the first frequency divider 11 according to the first demodulation signal to synchronize with a second frequency divider of the second touch controller 2. The demodulation unit 14 is further configured to receive a second sensing signal transmitted by the first receiving electrode 31, the second sensing signal being generated based on a second driving signal transmitted by the driving module to the first transmitting electrode 32. The demodulation unit 14 is further configured to demodulate the second sensing signal multiple times to obtain second demodulation signals of multiple frequencies, the second demodulation signals of the multiple frequencies being used to correct the frequency and phase of the first clock unit 13 to synchronize with a 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 train, or a timing pulse train. Correspondingly, the first receiving electrode 31 in the touch sensor 3, coupled to the first transmitting electrode 32, generates a first sensing signal, which is transmitted to the demodulation unit 14. The demodulation unit 14 demodulates the first sensing signal to obtain a first demodulated signal, which is then transmitted to the autocorrelator 12. The autocorrelator 12 then resets the first frequency divider 11 based on the first demodulated signal.

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

[0070] In this embodiment, the second touch controller 2 may include a second frequency divider, an automatic correlator, a second clock unit, and a demodulation unit. The connections and functions of these components can be found in [reference needed]. Figure 8 The connection relationships and functions of the components included in the first touch controller 1 shown are not described in detail here. Of course, the first touch controller 1 may also include a driver module. The function of the driver module can be found in the function of the driver module included in the second touch controller 2, which will also not be described in detail here.

[0071] As explained above, 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 a first sensing signal. The third receiving electrode transmits the first sensing signal to the demodulation unit of the second touch controller 2. The demodulation unit of the second touch controller 2 demodulates the first sensing signal to obtain a first demodulated signal, and transmits the first demodulated 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 demodulated signal. Thus, the first frequency divider 11 and the second frequency divider are reset based on the demodulated signals (including the first demodulated signal and the first demodulated signal) corresponding to the same driving signal, thereby achieving synchronization between the first frequency divider 11 and the second frequency divider.

[0072] In related technologies, the autocorrelator 12 is applied in a one-way stylus protocol. The function of the autocorrelator 12 includes detecting the timing of the stylus transmission pulse train. 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 touch controller's time must be consistent with the stylus's time. Therefore, the aforementioned autocorrelator 12 is used to detect the timing of the stylus transmission pulse train so that the touch controller's time is consistent with the stylus's time. In this embodiment, 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. Thus, based on the autocorrelator 12, the synchronization of the frequency dividers between different touch controllers (including the first touch controller 1 and the second touch controller 2) is achieved, ensuring the synchronization of different touch controllers.

[0073] Furthermore, 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. This second driving signal can be considered a synchronization pulse train. For example, the second driving signal could be... Figure 9 The transmission of the second drive signal, as shown in Sync 1 or Sync 2, can occur before the mutual capacitance measurement process (i.e., the mutual measurement process). Correspondingly, the first receiving electrode 31, coupled to the first transmitting electrode 32 in the touch sensor 3, generates a second sensing signal, which is transmitted to the demodulation unit 14. The demodulation unit 14 can demodulate the second sensing signal multiple times (e.g., at least twice), using a different frequency each time, resulting in multiple frequencies of second demodulated signals. These multiple frequencies of second demodulated signals 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. Exemplarily, this can be achieved by a processor (…). Figure 8 (Not shown) The frequency and phase of the first clock unit 13 are corrected according to the second demodulation signals of multiple frequencies.

[0074] In the related art, the demodulation unit 14 is applied in a one-way stylus protocol, and the role of the demodulation unit 14 includes demodulating multiple carrier signals on a designated 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 respectively, thereby determining the spatial positions of the two transmitting antennas relative to the touch sensor 3, that is, obtaining two different spatial positions, and based on the two different spatial positions, the angle of the stylus relative to the touch sensor 3 can be determined. In the embodiment of the present application, by using the demodulation unit 14, the second sensing signal can be demodulated multiple times, and the multiple frequency second demodulation signals obtained can be used to correct the frequency and phase of the first clock unit 13, thereby realizing the synchronization of the clock between different touch controllers (including the first touch controller 1 and the second touch controller 2) based on the demodulation unit 14, ensuring the synchronization of different touch controllers, and fully coupling and matching between different touch controllers to adapt to the slight changes in the transmission and demodulation process.

[0075] As can be seen from the foregoing description, in the embodiment of the present application, for a cascade system with multiple touch controllers, the synchronization of the frequency divider and the synchronization of the clock between different touch controllers are realized without the need to set up an external interface and / or additional circuit (such as a PLL), thereby facilitating the further realization of modulation synchronization and demodulation synchronization.

[0076] Next, the structure of the first touch controller 1 will be described in detail. Figure 10 The structure of the second touch controller 2 can be the same as that of the first touch controller 1, and will not be described again.

[0077] In the driving module of the first touch controller 1, the first sub-frequency divider, the second sub-frequency divider, the first sub-clock unit, the first NCO, the code segment counter, the CDM code memory, the driver, the first amplifier and the first pad are included, and the connection relationship between these elements is as shown in Figure 10 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-frequency divider divides the first clock signal, the first NCO generates a first carrier signal according to the divided signal, the second sub-frequency 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 driving signal according to the first carrier signal and the count stored in the CDM code memory, the first amplifier amplifies the driving signal, and the amplified driving signal is transmitted to the transmitting electrode of the touch sensor 3 through the first pad.

[0079] In the sensing module of the first touch controller 1, a second pad connected with a receiving electrode (for example, the first receiving electrode 31 described above) of the touch sensor 3, a second amplifier, a BPF, an ADC, a mixer (also referred to as a demodulator), a second NCO, an LPF, an auto-correlator 12, a second sub-clock unit, a third sub-divider, a fourth sub-divider, a sampler, and a multiplier are included, and the connection relationship among these elements is as shown in FIG. 2, which will not be described herein again. Among them, the mixer, the second NCO, and the LPF constitute a demodulation sub-unit, and the demodulation unit 14 described above can include at least one demodulation sub-unit, and the demodulation sub-unit shown in FIG. 2 is only an example. Figure 10 Figure 10 The demodulation sub-unit shown in FIG. 2 is only an example.

[0080] The first sensing signal and the second sensing signal described above 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 a digital signal corresponding to the first sensing signal, in addition, the second sub-clock unit provides a second clock signal, the third sub-divider divides the second clock signal, the second NCO generates a second carrier signal according to the divided signal, the mixer demodulates the digital signal corresponding to the first sensing signal according to the second carrier signal to obtain the first demodulation signal described above. The mixer transmits the first demodulation signal to the LPF, and the LPF filters the first demodulation signal to obtain a 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, and the first result matrix can be stored in the memory, so that the processor reads 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 filtered signal to the auto-correlator 12, and the auto-correlator 12 resets the third sub-divider and the fourth sub-divider according to the first filtered signal. The first divider 11 described above can include the third sub-divider and the fourth sub-divider.​Figure 10 The connection relationship between the automatic correlator 12 and the first sub-frequency divider is not shown, and the connection relationship between the automatic correlator 12 and the second sub-frequency divider is not shown.

[0084] The process in which the automatic correlator 12 resets the first frequency divider 11 according to the first filtered signal is described below. After the LPF transmits the first filtered signal to the automatic correlator 12, the automatic correlator 12 can accurately detect the time at which the LPF transmits the first filtered signal. Once the automatic correlator 12 detects the first filtered signal, the automatic correlator 12 transmits an effective 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 second clock signal described above) by 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-flop signal, thereby changing the state of the output clock signal (i.e., the signal after frequency division described above) and achieving the frequency division effect. The certain value described above is not limited in the present application, 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, the counter outputs a flip-flop signal when every 2 rising edges of the input clock signal reach the first frequency divider 11, that is, the output clock signal is flipped once.

[0086] The principle of frequency division of the first frequency divider 11 is described in the above paragraph. Based on this principle, the reset of the first frequency divider 11 refers to the reset of the counter inside the first frequency divider 11. That is, after the automatic correlator 12 transmits an effective signal to the first frequency divider 11, the first frequency divider 11 receives the effective signal and resets the counter inside the first frequency divider 11 according to the effective signal. Alternatively, the reset of the counter inside the first frequency divider 11 refers to resetting the counter to an initial value, for example, resetting the counter to zero.

[0087] As described above, the first frequency divider 11 can include a first sub-frequency divider, a second sub-frequency divider, a third sub-frequency divider, and a fourth sub-frequency divider. The reset of the first frequency divider 11 by the automatic correlator 12 according to the first filtered signal refers to the reset of the counters inside the first sub-frequency divider, the second sub-frequency divider, the third sub-frequency divider, and the fourth sub-frequency divider by the automatic correlator 12 according to the first filtered signal.

[0088] The automatic correlator 12 transmits the 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 the 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 the 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 the 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] Thus, in the first touch controller 1, the automatic correlator 12 realizes the reset of the first frequency divider 11 according to the first filtered signal (obtained based on the first demodulation signal), and each sub-frequency divider 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 automatic correlator' can also realize the reset of the second frequency divider according to the first filtered signal' (obtained based on the first demodulation signal'), and each sub-frequency divider included in the second frequency divider can also synchronously restart counting, flip the signal 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 driving signal, each sub-frequency divider included in the first frequency divider 11 and each sub-frequency divider included in the second frequency divider can synchronously restart counting, flip the signal and change the state of the output clock signal, thereby realizing the synchronization of the first frequency divider 11 and the second frequency divider, and further ensuring the consistency between the first touch controller 1 and the second touch controller 2. Thus, in the case that the modulation process and the demodulation process are performed 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 example embodiment, the first touch controller 1 is connected with the second touch controller 2 through a communication interface. The demodulation unit 14 is configured to receive the first sensing signal transmitted by the first receiving electrode 31 in response to receiving a start instruction transmitted by the second touch controller 2 through the communication interface. If the first touch controller 1 is required to continuously receive and demodulate the sensing signal (e.g., the first sensing signal), a large amount of power will be consumed. Therefore, a preliminary synchronization can be performed through the communication interface, i.e., the second touch controller 2 transmits a start instruction to the first touch controller 1 through the communication interface to instruct the first touch controller 1 to start the demodulation unit 14 (or a demodulation circuit) to prepare for receiving and demodulating the first sensing signal generated based on the first driving signal. For the first touch controller 1, in a case where the start instruction is not received, the elements inside the first touch controller 1 can be powered off based on a power management scheme, and in a case where the start instruction is received, the powered-off elements are powered on to prepare for receiving and demodulating the first sensing signal generated based on the first driving signal.

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

[0093] In an example, the demodulation unit 14 includes a plurality of demodulation sub-units as described above, and each demodulation sub-unit corresponds to a frequency. Taking one demodulation sub-unit as an example, the second NCO in the demodulation sub-unit generates a third carrier signal according to the divided signal at a corresponding frequency, 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 a plurality of demodulation sub-units obtain a plurality of second demodulation signals.

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

[0095] No matter which example above, a plurality of second demodulation signals corresponding to a plurality of frequencies can be obtained, the LPF filters the plurality of second demodulation signals to obtain a plurality of second filtered signals, the second filtered signal is also called a demodulation response, and the LPF is also called a demodulation response filter. Taking a plurality of frequencies including frequency A and frequency B as an example, Figure 11 The demodulation responses corresponding to frequency A and frequency B are shown respectively.

[0096] The LPF transmits the 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, and the multiplier performs multiplication processing on the plurality of second sampling matrices to obtain a plurality of second result matrices, which are stored in the memory.

[0097] In an exemplary embodiment, the second demodulation signals (i.e., the plurality of second demodulation 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 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, in the case where the second demodulation signals of the plurality of frequencies refer to two second demodulation signals, the normalized ratio can be determined according to the following formula by the embodiment of the application:

[0099]

[0100] Wherein, A represents the demodulation signal (or the corresponding demodulation response) corresponding to frequency A, B represents the demodulation signal (or the corresponding demodulation response) corresponding to frequency B, N represents the normalized ratio, M represents the correction coefficient, the value of the correction coefficient is not limited by the embodiment of the application, and the value of the correction coefficient can be 1, and Error represents the frequency error.

[0101] Or, in the case where the second demodulation signals of the plurality of frequencies refer to three or more second demodulation signals, the reference normalized ratio can be determined according to the above formula for each two second demodulation signals by the embodiment of the application, and then all the reference normalized ratios are weighted and summed (the weights corresponding to different reference normalized ratios can be the same or different), and the result of the weighted sum is taken as the determined normalized ratio.

[0102] Optionally, after the processor determines the normalized ratio, the processor determines a frequency error between the first clock unit 13 and the second clock unit according to the normalized ratio, and corrects the frequency and phase of the first clock unit 13 according to the frequency error. For example, 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 example embodiment, the demodulation unit 14 is also connected to a second receiving electrode of the touch sensor 3, the second receiving electrode is coupled to a 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 further configured 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 14 is further configured to demodulate the plurality of data bits to obtain the communication data.

[0104] In the embodiments of the present application, since the frequency divider and the clock of the first touch controller 1 and the second touch controller 2 are synchronized, the first touch controller 1 and the second touch controller 2 have a strong coupling relationship, which can support more efficient encoding, for example, a phase modulation scheme. Based on the phase modulation scheme, the first touch controller 1 and the second touch controller 2 can directly communicate through the coupled electrodes in the touch sensor 3, without the need to set a dedicated communication interface between the first touch controller 1 and the second touch controller 2, for example, without the need to set an I 2 C (inter-integrated circuit, integrated circuit bus) or SPI (serial peripheral interface, serial peripheral interface) and other communication interfaces.

[0105] For example, the phase modulation scheme includes a phase modulation scheme with multiple phase increments. The second touch controller 2 modulates multiple data bits to be transmitted according to this phase modulation scheme. These multiple data bits carry the communication data to be exchanged, and are transmitted to the first touch controller 1 through the driving module and the second transmitting electrode of the touch sensor 3. During transmission, each symbol can use a 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 and demodulate the multiple data bits through the second receiving electrode of the touch sensor 3 to obtain the communication data carried by the multiple data bits, thus realizing communication between the first touch controller 1 and the second touch controller 2. This makes it 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 matched signal levels.

[0107] In the touch sensor 3, not all transmitting and receiving electrodes need to be used; unused transmitting and receiving electrodes may also exist. In this embodiment, unused transmitting and receiving electrodes can be reused as the aforementioned second transmitting and second receiving electrodes, improving the electrode utilization rate of the touch sensor 3. This embodiment can also ensure that the second receiving electrode and the second transmitting electrode have matched signal levels, for example, through passive circuitry. This method is beneficial for achieving a better SNR (signal-to-noise ratio), avoiding the need for retransmission through the touch sensor 3 when the SNR is poor.

[0108] In summary, this embodiment of the application uses an automatic correlator to reset the frequency divider, avoiding misalignment of the frequency dividers in different touch controllers and ensuring synchronization of the frequency dividers in different touch controllers. This embodiment also uses demodulation to obtain second demodulated signals of multiple frequencies, determining the frequency error between the clocks in different touch controllers, thereby facilitating the correction of clock frequency and phase, and ensuring frequency and phase synchronization of the clocks in different touch controllers. Therefore, it provides strong synchronization between different touch controllers, is suitable for scenarios where different touch sensors are cascaded, and is suitable for use with larger screens (or touch panels).

[0109] This application also provides a synchronization method, which can be executed by the first touch controller described above. For example... Figure 12 As shown, the method includes, but is not limited to, steps 1201 to 1205.

[0110] At step 1201, the first sensing signal transmitted by the first receiving electrode of the touch sensor is received by the demodulation unit, the first sensing signal is generated based on the first driving signal transmitted by the driving module of the second touch controller to the first transmitting electrode of the touch sensor.

[0111] In an example embodiment, receiving, by the demodulation unit, the first sensing signal transmitted by the first receiving electrode of the touch sensor comprises: in response to receiving, by the communication interface, the start instruction transmitted by the second touch controller, performing, by the demodulation unit, receiving, by the demodulation unit, the first sensing signal transmitted by the first receiving electrode of the touch sensor.

[0112] At step 1202, the first sensing signal is demodulated by the demodulation unit to obtain a first demodulation signal.

[0113] At step 1203, the first divider of the first touch controller is reset according to the first demodulation signal by the auto-correlator to synchronize with the second divider of the second touch controller.

[0114] At step 1204, the second sensing signal transmitted by the first receiving electrode is received by the demodulation unit, the second sensing signal is generated based on the second driving signal transmitted by the driving module to the first transmitting electrode.

[0115] At step 1205, the second sensing signal is demodulated by the demodulation unit multiple times to obtain a plurality of frequency second demodulation signals, the plurality of frequency second demodulation signals 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 example embodiment, the plurality of frequency second demodulation signals 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, the frequency error is used to correct the frequency and phase of the first clock unit.

[0117] In an example embodiment, 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 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; demodulating, by the demodulation unit, the plurality of data bits to obtain the communication data.

[0118] In an example 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] Figure 12 The method embodiments shown above are described in detail above Figure 8 and Figure 10The first touch controller shown belongs to the same concept, and therefore, the method embodiments correspond to the specific implementation and technical effects described above Figure 8 and Figure 10 The corresponding description is not repeated here.

[0120] In exemplary embodiments, the embodiments of the present application also provide a chip, which includes the first touch controller described above.

[0121] Exemplarily, the embodiments of the present application also provide an electronic device, which includes a touch sensor, a first touch controller and a second touch controller, the first touch controller and the second touch controller are connected to the touch sensor respectively. For example, the electronic device is a display device.

[0122] The terms "first", "second", and the like (if any) in the specification and claims of the present application are used to distinguish similar objects, and do not necessarily have to describe a specific order or chronological sequence. It should be understood that the data used in this way can be exchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. The implementation described in the above exemplary embodiments does not represent all implementations consistent with the present application. Rather, they are only 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 "multiple" referred to herein means two or more. "And / or", which describes the association between the associated objects, means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the associated objects before and after are in an "or" relationship.

[0124] The above description is only exemplary embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, 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, which includes 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. The demodulation unit is also connected to the autocorrelator and the first receiving electrode of the touch sensor. The first receiving electrode is coupled to the first transmitting electrode of the touch sensor. The first transmitting electrode is connected to the driving module of the second touch controller. The demodulation unit is used to receive a first sensing signal transmitted by the first receiving electrode, the first sensing signal being generated based on a first driving signal transmitted by the driving module to the first transmitting electrode; The demodulation unit is further configured to demodulate the first sensing signal to obtain a first demodulated signal; The automatic correlator is used to reset the first frequency divider according to the first demodulated signal so as to synchronize with the second frequency divider of the second touch controller; The demodulation unit is further configured to receive a second sensing signal transmitted by the first receiving electrode, the second sensing signal being generated based on a second driving signal transmitted by the driving module to the first transmitting electrode; The demodulation unit is further configured to demodulate the second sensing signal multiple times to obtain second demodulated signals of multiple frequencies. The second demodulated 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 touch controller according to claim 1, characterized in that, The second demodulated signals of the plurality of frequencies correspond to a normalization ratio, which is used to determine the 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.

3. The touch controller according to claim 1 or 2, characterized in that, The first touch controller and the second touch controller are connected via a communication interface; The demodulation unit is configured to, in response to receiving a start command 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 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 further configured 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 carry communication data. The demodulation unit is further configured to demodulate the plurality of 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 matched signal levels.

6. A synchronization method, characterized in that, The method includes: The demodulation unit receives a first sensing signal transmitted from the first receiving electrode of the touch sensor, and the first sensing signal is generated based on a first driving signal transmitted from the driving module of the second touch controller to the first transmitting electrode of the touch sensor. The first sensing signal is obtained by demodulating the first sensing signal through the demodulation unit; The first frequency divider of the first touch controller is reset by an automatic correlator according to the first demodulated signal to synchronize with the second frequency divider of the second touch controller; The demodulation unit receives a second sensing signal transmitted by the first receiving electrode, and 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 demodulated signals of multiple frequencies. The second demodulated signals of multiple frequencies are used to correct the frequency and phase of the first clock unit of the first touch controller so as 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 plurality of frequencies correspond to a normalization ratio, which is used to determine the 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.

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

9. The method according to claim 6 or 7, characterized in that, The method further includes: The demodulation unit receives multiple data bits transmitted by the second receiving electrode of the touch sensor. The multiple data bits are transmitted by the driving module through the second transmitting electrode of the touch sensor. The multiple data bits are obtained by phase modulation and carry communication data. The communication data is obtained by demodulating the plurality of data bits through the demodulation unit.

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 matched signal levels.

11. A chip, characterized in that, The chip includes the first touch controller as described in any one of claims 1-5.

12. An electronic device comprising a touch sensor, a first touch controller as described in any one of claims 1-5, and a second touch controller.

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