Touch driving apparatus, touch device and touch driving method

Abstract

Touch driving apparatus, touch control apparatus and touch driving method are provided. The touch driving apparatus is used for driving a mutual capacitance type touch panel. The touch driving apparatus includes at least one output module and a controller. Each output module includes at least two output stage circuits, and an output end of each output stage circuit is used for outputting a driving signal to a connected driving electrode. The touch driving method includes: for each output module, determining, according to a code division multiple access (CDM) code matrix, a first group of output stage circuits and a second group of output stage circuits in a current driving period, wherein a first group of driving signals of the output ends of the first group of output stage circuits are expected to discharge a first group of driving electrodes, and a second group of driving signals of the output ends of the second group of output stage circuits are expected to charge a second group of driving electrodes; and in response to the determination, controlling charging of the second group of driving electrodes with power from the first group of driving electrodes.

Description

Technical Field

[0001] This application relates to the field of touch control, and more specifically, to a touch driving device, a touch control device, and a touch driving method. Background Technology

[0002] In recent years, touch devices, including so-called touch panels, which can detect the proximity of external objects, have attracted attention. Touch panels are mounted on or integrated with display devices such as LCD displays and OLED displays, thereby serving as touch display devices with touch detection capabilities.

[0003] Touch sensors, such as projected capacitive touch sensors, can be provided on the touch panel. The touch sensors can implement mutual capacitance or self-capacitance sensing operation modes. In a mutual capacitance implementation or operation mode, the touch sensor can include an array of driving and sensing electrodes forming an array of capacitive nodes. The overlapping areas of the driving and sensing electrodes can form capacitive nodes, and the driving and sensing electrodes can be capacitively coupled to each other across the space between them. A driving signal applied to the driving electrode (TX) by the touch circuitry (control circuitry for touch detection) can induce charge on the sensing electrode based on the coupled mutual capacitance, and the amount of induced charge can be easily affected by external factors (e.g., touch or the proximity of an object).

[0004] The touch circuit provides a touch sensing signal to a processing device (e.g., a CPU) by measuring the capacitance change across the mutual capacitance array formed by the driving and sensing electrodes. The processing device then determines the position or proximity of a touch within the touch-sensitive area of ​​the touch sensor. In the case of a touch display device or a touch display device with fingerprint recognition functionality, the processing device can also interact with display driving circuitry and / or fingerprint recognition control circuitry to control display operation and fingerprint recognition operation.

[0005] For the touch detection process of touch panels, achieving the lowest possible noise and power consumption, thereby improving detection accuracy and reducing power costs, has been a goal pursued by the industry. Summary of the Invention

[0006] This application aims to provide a touch driving device and a touch driving method to achieve low noise and low power consumption in the touch detection process.

[0007] According to one aspect of this application, a touch driving device for a touch sensor is provided, wherein the touch sensor includes a plurality of driving electrodes and a plurality of sensing electrodes arranged in a cross configuration, the touch driving device comprising: at least one output module, each output module including at least two output stage circuits, the output of each output stage circuit being configured to output a driving signal to a connected driving electrode; a controller configured to: for each output module, determine, according to a code division multiple access (CDM) code matrix, a first set of output stage circuits and a second set of output stage circuits during a current driving period, wherein a first set of driving signals at the output of the first set of output stage circuits is intended to discharge the first set of driving electrodes, and a second set of driving signals at the output of the second set of output stage circuits is intended to charge the second set of driving electrodes; and, in response to the determination, control the charging of the second set of driving electrodes using power from the first set of driving electrodes.

[0008] According to one aspect of this application, a touch device is provided, comprising: a touch panel including a plurality of driving electrodes and a plurality of sensing electrodes arranged in a cross configuration; and a touch driving device as described above, the touch driving device being configured to provide driving signals to the driving electrodes on the touch panel.

[0009] According to another aspect of this application, a touch driving method for a touch sensor is provided, the touch sensor including a plurality of driving electrodes and a plurality of sensing electrodes arranged in a cross configuration, the plurality of driving electrodes being divided into at least one group, each group corresponding to an output module, each output module including an output stage circuit having the same number of driving electrodes as each group, the method comprising: for each output module, determining a first group of output stage circuits and a second group of output stage circuits in a current driving period according to a code division multiple access (CDM) code matrix, wherein a first group of driving signals at the output of the first group of output stage circuits is intended to discharge the first group of driving electrodes, and a second group of driving signals at the output of the second group of output stage circuits is intended to charge the second group of driving electrodes; and in response to the determination, controlling the charging of the second group of driving electrodes using power from the first group of driving electrodes.

[0010] Based on the touch driving device, touch control device, and touch driving method described in this application, by modularizing multiple output stage circuits corresponding to multiple driving electrodes on the touch panel, driving signals can be generated and controlled for each output module. Secondly, by utilizing the energy interaction characteristic between driving signals during the generation of driving signals using code division multiple access, path switches are set between driving electrodes, thereby enabling the charging and discharging process between driving electrodes. This reduces interference and improves detection accuracy through code division multiple access while also reducing the power required by the touch driving device to supply to the driving electrodes, thus reducing power consumption. Attached Figure Description

[0011] Figure 1 A schematic diagram of the structure of a touch device according to an embodiment of this application is shown.

[0012] Figure 2A An example touch sensor incorporating time-division multiplexing (TDM) according to an embodiment of this application is shown.

[0013] Figure 2B An example touch sensor incorporating code division multiplexing (CDM) according to an embodiment of this application is shown.

[0014] Figure 2C This diagram illustrates the driving waveforms corresponding to the Hadamard code matrix.

[0015] Figure 3 A schematic diagram of an output stage circuit according to an embodiment of this application is shown.

[0016] Figure 4 A schematic diagram of a touch driving device for a touch panel according to an embodiment of this application is shown.

[0017] Figure 5 A schematic diagram of another touch driving device for a touch panel according to an embodiment of this application is shown.

[0018] Figures 6A-6B A schematic diagram of the charge / discharge path arranged between every two output stage circuits according to an embodiment of this application is shown.

[0019] Figures 7A-7D A schematic diagram of the charge / discharge path between every two output stage circuits using a shared charging bus, according to an embodiment of this application, is shown.

[0020] Figure 8-13 A schematic structure of a touch driving device including a comparison unit according to an embodiment of this application is shown.

[0021] Figure 14 A flowchart illustrating a method for a touch driving device for a touch panel according to an embodiment of this application is shown. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.

[0023] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising," "including," etc., mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The terms "connected," "linked," etc., are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Figure 1 A schematic diagram of the structure of a touch device according to an embodiment of this application is shown.

[0025] like Figure 1 As shown, the touch device 100 includes a touch circuit 101 and a touch sensor 102.

[0026] The touch circuit 101 includes a signal generator 111, a driver 121, a flexible circuit board pad 131, a flexible circuit board pad 141, an amplifier 151, a multiplexer 161, a filter 171, and a memory 18, etc.

[0027] The touch sensor 102 includes multiple TX lines (driving electrodes) and each RX line (sensing electrode). A capacitor is formed where the TX and RX lines intersect; that is, the TX and RX lines respectively constitute the two terminals of a capacitor. The driver 121 is electrically connected to the TX lines via flexible circuit board pads 131 to transmit a driving signal to the TX lines. This driving signal can, for example, be a noise-free carrier signal of a predetermined frequency. After the driver 121 transmits the driving signal to the TX lines, the same carrier signal can be used, for example, to amplify and demodulate the signal from the RX lines through amplifier 151, multiplexer 161, and filter 171.

[0028] The touch circuit can apply drive signals to multiple driving electrodes of the touch sensor and receive touch sensing signals from multiple sensing electrodes of the touch sensor. After processing the received touch sensing signals, it provides them to a processing device (e.g., a processor, MCU, DSP, ASIC, or a combination thereof), enabling the processing device to determine the location where a finger or other object touches or approaches the touch sensor. The touch circuit can be integrated into a single chip. Furthermore, in the case of a touch display device or a touch display device with fingerprint recognition functionality, the processing device can also interact with a display driving circuit and / or a fingerprint recognition control circuit to control display operations and fingerprint recognition operations. Simultaneously, at least a portion of the touch circuit, display driving circuit, and / or fingerprint recognition control circuit can be integrated into a single chip, such as a TDDI (Touch and Display Integration) chip and an FTDI (Fingerprint Recognition, Touch, and Display Integration) chip.

[0029] The touch device 100 may include various electronic devices with touch functionality (and may also include display functionality and / or fingerprint recognition functionality, etc.), such as, but not limited to, mobile phones, tablets, personal digital assistants, wearable devices, etc.

[0030] Figure 2A This application describes an example of a touch sensor incorporating time-division multiplexing (TDM) according to embodiments of the present application. Figure 2B This application describes an example touch sensor incorporating code division multiplexing (CDM) according to embodiments of the present application. Figure 2C This diagram illustrates the driving waveforms corresponding to the Hadamard code matrix.

[0031] When measuring the mutual capacitance at various intersection points during touch detection, a time-division multiplexing (TDM) method can be used. This involves sequentially scanning the driving electrodes at different times using a preset noise-free driving signal (e.g., a carrier signal), and reading the electrical signal from all sensing electrodes at each time (e.g., then amplifying and demodulating using the same carrier signal). However, this approach can result in a longer sensing time because the electrical signal needs to be read from each driving electrode in a time-division manner. Furthermore, touch sensor designs using the TDM method cannot adequately address noise signals attributable to the environment or other types of interference appearing on the sensing electrodes, potentially leading to a low signal-to-noise ratio (SNR) of the sensed signal.

[0032] As an improvement to Time Division Multiplexing (TDM), Code Division Multiplexing (CDM) can be used. In this CDM method, a set of driving electrodes can be selected simultaneously, and a set of driving signals corresponding to a preset CDM code matrix (the matrix size is determined by the number of driving electrodes) can be provided. For example, the reference driving signal is encoded using the preset code matrix to obtain the driving signal corresponding to the preset CDM code matrix for that set of driving electrodes. Then, the resulting codes obtained from all sensing electrodes are demodulated. For example, by multiplying the resulting codes by the inverse of the preset CDM code matrix, the mutual capacitance value at the intersection of each driving electrode and sensing electrode can be obtained, thereby determining whether a change has occurred.

[0033] For example, let's take encoding the reference drive signal into the drive signals of the four drive electrodes using a preset 4x4 Hadamard code matrix. In this case, the inner product of any different rows (columns) in the Hadamard code matrix is ​​0. The 4x4 Hadamard code can be represented as follows:

[0034]

[0035] Accordingly, the driving waveform corresponding to this Hadamard code matrix can be as follows: Figure 2C As shown.

[0036] exist Figure 2C In the diagram, the horizontal direction is the time axis, and four drive signals are simultaneously applied to the drive electrodes TX[N], TX[N+1], TX[N+2], and TX[N+3]. Each code value in the code matrix corresponds to the waveform of the drive signal applied within a code segment (with a preset duration). For example, when the code value is 1, the waveform of the applied drive signal (within one code segment) is the same as the reference drive signal; when the code value is -1, the waveform of the applied drive signal (within one code segment) lags behind the reference drive signal by 180°.

[0037] Of course, the Hadamard code matrix is ​​merely an example for encoding the drive signal; other codes can be used to encode the reference drive signal, and the matrix dimensions can be chosen as needed. For example, a proprietary code matrix can be used, which includes codes in each code segment whose sum of 1 and -1 for each drive electrode is close to zero (i.e., so-called DC balanced codes). This reduces coupling noise entering the display panel due to paths formed by parasitic capacitances between the drive electrodes and display electrodes in the display panel (e.g., gates, data lines, and / or common electrodes), thereby reducing visual artifacts and improving display quality. Similarly, using the Hadamard code matrix can also reduce the sum of 1 and -1 for each drive electrode in each code segment to some extent, thus also reducing noise and improving display quality.

[0038] Furthermore, by using CDM methods, such as encoding, the multiplexed drive signal can be distributed across many frequencies, thereby avoiding intra-band interference between drive-sensing electrode pairs (one drive electrode and all sensing electrodes are called a drive-sensing pair), and thus increasing the signal-to-noise ratio of the sensed signal of the touch sensor.

[0039] In some cases, touch circuits use square wave signals as drive signals, such as... Figure 2C As shown, the driving signal can also include triangular wave signals, sine wave signals, and other signals.

[0040] In addition, the power supply voltage of touch circuits is generally low. For example, in the case of a mobile phone, the mobile phone battery can only provide a voltage signal of about 3.3V, but the amplitude of the drive signal can be, for example, 6V. Therefore, a boost circuit is required in the touch circuit to boost the voltage in order to obtain the amplitude required by the drive signal.

[0041] When using the CDM method, when a drive signal is applied to the drive electrode, the current supplied to the touch sensor while the drive signal charges the mutual capacitance on the drive electrode in the touch sensor can be approximated by the expression shown in Equation 1, which assumes that each drive electrode is fully charged by the applied drive signal.

[0042] I = N × C TX ×F×V (1)

[0043] Where I is the average current supplied from the touch circuit to the driving electrodes, N is the number of driving electrodes, and C TX The total capacitance value of the mutual capacitance on each driving electrode, F is the carrier frequency used for measurement, and V is the amplitude of the driving signal.

[0044] In a typical case, N = 17, CTX =500pF, F=180kHz, V=6V; therefore, we can calculate I=17×500pF×180kHz×6V=9mA.

[0045] Furthermore, mutual capacitance measurements are typically performed at 120Hz with a scan time of 2ms, resulting in a total duty cycle of 24%. Since the boost circuit and other related circuits generally operate at 90% efficiency, the approximate power consumption of the touch circuit's drive can be calculated as follows:

[0046] Power=V×I×Duty×(1+(1-efficiency))=9mA×6V×24%×110%=15mW(2)

[0047] This power consumption is quite significant in typical touch circuits, thus reducing the efficiency of touch circuits when performing touch detection operations.

[0048] Therefore, this application proposes a solution that can reduce the power consumption of the touch circuit during touch detection operations, thereby improving efficiency.

[0049] First, a brief introduction to the output stage circuit of the drive signal in the touch circuit. Figure 3 A schematic diagram of an output stage circuit according to an embodiment of this application is shown.

[0050] The output stage circuit can perform signal shaping (e.g., generating square wave drive signals) or improvement, noise reduction, etc., on each drive control signal in the touch circuit so that the waveform of the drive signal meets the design requirements. Optionally, this output stage circuit can be integrated into the same chip as the touch circuit used for touch detection, but it can also be independent of the touch circuit.

[0051] It should be understood that, such as Figure 3 The output stage circuit shown is merely an example; it can be any other circuit capable of improving or shaping the waveform of the input drive control signal to obtain the drive signal. Furthermore, it should be noted that while most of this application describes the controller providing drive signals to the drive electrodes via the output stage circuit, in some embodiments, the controller can directly provide drive signals to the drive electrodes without requiring an output stage circuit.

[0052] like Figure 3 As shown, the output stage circuit may include a first switch and a second switch connected in series between a high-voltage power supply terminal (providing a preset high level TXVDD, such as 6V) and a low-voltage power supply terminal (such as providing a preset low level 0V), and the connection node of the first switch and the second switch is connected to the output terminal of the output stage circuit.

[0053] Optionally, the output stage circuit includes a series branch of two transistors (T1 and T2) with opposite polarities. The first terminal of the upper transistor T1 (e.g., a P-type transistor) is connected to a high-level power supply terminal (with a preset high level TXVDD, e.g., 6V), and its second terminal is connected to the first terminal of the lower transistor T2. The control terminal of the lower transistor T2 (e.g., an N-type transistor) is connected to the second terminal of the upper transistor T1, and its second terminal is connected to a low-level power supply terminal (with a preset low level, e.g., zero). The control terminal of this lower transistor T2 is also used to receive the same drive control signal as the first transistor T1. The connection node between the upper transistor T1 and the lower transistor T2 is connected to the output terminal OUTPUT of the output stage circuit, which outputs the drive signal applied to the drive electrode. In the following text, "drive signal" refers to the drive signal at the output terminal of the output stage circuit.

[0054] Of course, transistors T1 and T2 can also be other types of transistors and can be controlled by independent control signals, as long as they can be turned on and off to periodically change the output voltage value between a preset high level and a preset low level. For example, T1 and T2 can be transistors of the same type, and the control signal for T1 can be a drive control signal, while the control signal for T2 can be the inverted version of the drive control signal.

[0055] based on Figure 3 In the circuit shown, when the level of the drive control signal Scon exceeds the first threshold level, transistor T2 is turned on and transistor T1 is turned off, resulting in a preset low level output at the OUTPUT terminal. When the level of the drive control signal Scon is lower than the second threshold level, transistor T2 is turned off and transistor T1 is turned on, resulting in a preset high level output at the OUTPUT terminal. The values ​​of the first and second threshold levels are determined by the transistor parameters (e.g., threshold voltage Vth). Therefore, the amplitude of the drive signal TXdrv output from the OUTPUT terminal varies between the preset high and preset low levels, resulting in good signal quality. Furthermore, by setting the value of the preset high level, sufficient driving capability of the output drive signal can be guaranteed.

[0056] Returning to the power consumption calculation of the touch circuit, the power consumption calculated above using equations (1)-(2) is based on the power consumption from the power supply (e.g., Figure 3 All current flowing from the high-level power supply terminal (in the circuit) to charge the mutual capacitance on each drive electrode and from the mutual capacitance on each drive electrode to the reference terminal (e.g., Figure 3 The calculation is performed by releasing the current (from the low-level power supply terminal).

[0057] Considering that in the CDM method, there may be opposite code values ​​(e.g., 1 and -1) in each code segment, the corresponding drive signals may have a phase shift. Therefore, the amplitude difference between at least two drive signals in each drive period (e.g., half the duration of the drive cycle) included in the code segment will be large enough. For example, the voltage value of the drive signal for the first drive electrode at the end of the previous drive period is 6V, and the expected voltage value in the current drive period is 0V. At the same time, the voltage value of the drive signal for the second drive electrode at the end of the previous drive period is 0V, and the expected voltage value in the current drive period is 6V. Therefore, the drive signals applied to different drive electrodes in the current drive period are expected to discharge the mutual capacitance on the first drive electrode and charge the mutual capacitance on the second drive electrode. At this time, the scheme proposed in this application can use at least a portion of the power released by the mutual capacitance on the first drive electrode to charge the mutual capacitance on the second drive electrode. Therefore, the power drawn from the touch circuit (e.g., an internal power supply providing 6V voltage) can be reduced, thereby reducing the power consumption of the touch circuit when performing touch detection operations.

[0058] The following will combine Figure 4-9 The present application will now describe in detail the touch driving device and touch driving method according to embodiments thereof.

[0059] Figure 4 A schematic diagram of a touch driving device for a touch panel according to an embodiment of this application is shown. Optionally, the touch driving device may be as follows: Figure 1 The touch circuit shown may include, for example, the touch circuitry. Figure 1 The touch circuit shown includes a plurality of driving electrodes and a plurality of sensing electrodes arranged vertically in a cross configuration, with mutual capacitance formed at each intersection of the plurality of driving electrodes and the plurality of sensing electrodes.

[0060] According to some embodiments, the touch driver may include a controller.

[0061] The controller can determine the first group of driving electrodes and the second group of driving electrodes in the current driving period based on the code division multiple access (CDM) code matrix, wherein the first group of driving electrodes is the driving electrode that is expected to be discharged in the current driving period, and the second group of driving electrodes is the driving electrode that is expected to be charged in the current driving period, and in response to the determination, the controller uses the power from the first group of driving electrodes to charge the second group of driving electrodes.

[0062] For example, the controller may not provide any signals to the first set of drive electrodes while the second set of drive electrodes is charging, and after charging is complete, it may provide a low voltage to the first set of drive electrodes to release any remaining power from the first set of drive electrodes, and provide a high level to the second set of drive electrodes to continue charging.

[0063] Optionally, there is a charge / discharge path between the first set of driving electrodes and the second set of driving electrodes that can be controlled by a controller.

[0064] Alternatively, the touch driver can be modularly designed, in which the multiple driving electrodes are divided into multiple groups, and the controller applies the same code division multiple access (CDM) code matrix to the control signals generated for each group.

[0065] According to other embodiments, as described above, in order to better shape and improve the drive signal and reduce the requirements on the controller function, output stage circuits can be introduced, wherein the input of each output stage circuit receives drive control signals from the controller, and the output is used to output drive signals to the connected drive electrodes.

[0066] It should be understood that the settings related to the output terminals of the referenced output stage circuit below also apply to the output terminals of the controller connected to the drive electrodes without the output stage circuit, such as path switches connected between output terminals, path switches connected to the charging shared bus, etc.

[0067] like Figure 4 As shown, the touch driver 400 may include at least one output module 410 and a controller 420.

[0068] At least one output module 410 refers to modules 410-1, 410-2, ... obtained by modularizing multiple output stage circuits used to provide drive signals to multiple drive electrodes. Each output module is connected to a set of drive electrodes on the touch panel, the number of which is the same as the number of output stage circuits included in the output module.

[0069] For example, each output module includes at least two output stage circuits 415-1, 415-2, ..., and the output terminal OUTPUT of each output stage circuit is used to output a drive signal to a connected drive electrode. Of course, modularization is also possible, in which case all output stage circuits can be regarded as one output module.

[0070] Alternatively, the structure of each output stage circuit 415-1, 415-2, ... can be as described in the previous reference. Figure 3The described output stage circuit structure generates a square wave signal that switches between a preset high level (TX / VDD) and a preset low level based on the input drive control signal, which serves as the drive signal provided to the drive electrodes. The number of drive control signals input to each output stage circuit can be one or more, depending on the circuit structure and device parameters of the output stage circuit.

[0071] The controller 420 can be configured to perform the same or similar operations for each output module. For example, for each output module, the controller 420 can determine, based on a code division multiple access (CDM) code matrix, a first set of drive signals at the output of the first set of output stage circuits is expected to discharge the first set of drive electrodes, and a second set of drive signals at the output of the second set of output stage circuits is expected to charge the second set of drive electrodes; and in response to this determination, control the charging of the second set of drive electrodes using power from the first set of drive electrodes.

[0072] For example, the CDM code matrix can be the matrix used when employing the CDM method to generate drive signals that are simultaneously applied to each drive electrode, as referenced above. Figure 2B-2C As described. The controller can acquire or read a preset CDM code matrix from an external source, and based on this CDM code matrix, determine the timing of the drive signals expected to be applied to each drive electrode during the current drive period. This allows the determination of a first set of output stage circuits and a second set of output stage circuits during the current drive period. A first set of drive signals at the output of the first set of output stage circuits is expected to discharge the first set of drive electrodes, and a second set of drive signals at the output of the second set of output stage circuits is expected to charge the second set of drive electrodes. According to the CDM code matrix, the first set of output stage circuits and the second set of output stage circuits may each include one or more output stage circuits. However, according to the CDM code matrix, it is possible that during a time period corresponding to a certain code segment, for example... Figure 2C During the time period corresponding to the first code segment, the drive signals applied to each drive electrode are synchronous (e.g., the corresponding code values ​​are all 1 or -1). At this time, only the first set of output stage circuits or the second set of output stage circuits exist, and therefore there is no charging and discharging process between the drive electrodes as described later.

[0073] For example, the controller can first determine the timing of the drive signal corresponding to each drive electrode based on the CDM code matrix, where each drive signal includes multiple drive periods, and the duration of each drive period is half the period of the drive signal, such as... Figure 2CThe DT period shown is a driving period; then for each driving period, the controller further determines the first set of output stage circuits and the second set of output stage circuits based on the determined timing of the driving signals corresponding to each driving electrode, and also controls each output stage circuit based on the voltage value at the output terminal of each output stage circuit in the current driving period (in real time, which will change with the charging and discharging process), for example, controlling the on and off of the switches in the output stage circuit and the on and off of the path switches between the output stage circuits as described later, to replace the charging and discharging process between the driving electrodes at appropriate times, so as to charge the driving electrodes with a high voltage source and / or discharge the driving electrodes to a low voltage power supply terminal.

[0074] Optionally, during the charging and discharging process between the driving electrodes, the controller 420 can control the use of power from the first group of driving electrodes to charge the second group of driving electrodes for a first time period, and after the first time period, control the release of the remaining power from the first group of driving electrodes to a low-level power supply terminal, and use a high-level power supply terminal to continue charging the second group of driving electrodes.

[0075] For example, when the output stage circuit uses, Figure 3 In the described circuit structure, each output stage circuit includes a first switch T1 and a second switch T2 connected in series between a high-voltage power supply terminal and a low-voltage power supply terminal. The connection node of the first switch T1 and the second switch T2 is connected to the output terminal of the output stage circuit. The controller can charge the drive electrode connected to the output terminal of the output stage circuit using the high-level power supply terminal by turning on the first switch and turning off the second switch of each output stage circuit. Furthermore, by turning on the second switch and turning off the first switch of each output stage circuit, the remaining power from the drive electrode connected to the output terminal of the output stage circuit is released to the low-level power supply terminal (e.g., after the charging and discharging process between the drive electrodes has ended, i.e., after a first time period). In addition, during the charging and discharging process between the drive electrodes (e.g., during the first time period), the controller turns off both the first and second switches included in each output stage circuit.

[0076] In other words, the power from the first set of driving electrodes can only provide a portion of the power required to charge the second set of driving electrodes to a preset high level (e.g., TX VDD). For example, when the voltages of these driving electrodes have become equal or balanced after a first time period of charging and discharging, or when it is determined, based on other conditions (e.g., the current driving period has started for a preset duration), that the charging and discharging process between the driving electrodes should be stopped, there should be no current flowing between the driving electrodes. However, at this time, the second set of driving electrodes has not yet been fully charged (i.e., charged to the preset high level), and the voltage on the first set of driving electrodes has not yet been released to the preset low level (e.g., 0). Therefore, an additional power source is needed to continue charging the second set of driving electrodes and to release the remaining power on the first set of driving electrodes.

[0077] Optionally, the controller may include various processing devices (e.g., including but not limited to CPU, DSP, FPGA, ASIC, MCU, etc.) capable of implementing the above control functions, and may also include storage devices (e.g., including but not limited to memories such as RAM, ROM, cache, or other types of storage devices) for storing instructions, programs, information, or data required to implement the above control or determination process.

[0078] By reference Figure 4 The described touch driver device 400 can charge a drive electrode that needs to be charged using a drive electrode that needs to release power. The touch driver device can provide power to the drive electrode that needs to be charged only after the drive electrode has been charging for a period of time, thereby reducing the power that needs to be provided by the touch driver device to the drive electrode, and thus reducing the power consumption of the touch driver device.

[0079] As a response Figure 4 Further explanation of the aforementioned touch driving device, Figure 5 A schematic diagram of another touch driving device for a touch panel according to an embodiment of this application is shown.

[0080] like Figure 5 As shown, the touch driving device 400 may further include at least one path switch SW1, SW2... disposed between the output terminals of every two output stage circuits in each of the at least two output stage circuits in each output module, for providing a charging and discharging path between the driving electrodes. Although not shown, the at least one path switch may also be a switch between each output terminal and the charging shared bus described later. Optionally, these path switches may be disposed in each output module (e.g., ...). Figure 6A As shown), it can also be independent of the output module (such as...). Figure 6B (As shown).

[0081] As mentioned earlier, in each driving period, whether the driving signal output by each output stage circuit charges or discharges the connected driving electrode can be determined based on the CDM code matrix. Therefore, the driving electrode connected to each output stage electrode circuit may not need to be discharged or charged by other driving electrodes (e.g., with the same code value), or it may be a driving electrode that needs to be charged by other driving electrodes in the output module or a driving electrode that needs to release power to other driving electrodes in the output module. Therefore, a path switch may be required between the output terminals of every two output stage circuits in each output module, so that when a charging and discharging process between driving electrodes is required, these path switches can provide one or more corresponding charging and discharging paths under the control of the controller.

[0082] For example, considering the structure of the output stage circuit, during a first time period (the period in which the power from the first group of driving electrodes is used to charge the second group of driving electrodes), the controller disables the first group of output stage circuits and the second group of output stage circuits, and controls the conduction of at least a portion of the path switches, so that the power from the first group of driving electrodes charges the second group of driving electrodes; and after the first time period, the controller enables the conduction path between the output terminal of the first group of output stage circuits and the low-level power supply terminal and the conduction path between the high-level power supply terminal and the output terminal of the second group of output stage circuits, and controls the turn-off of the at least a portion of the path switches.

[0083] As an example, such as Figure 6A As shown, an output module includes two output stage circuits. Assuming that the CDM code matrix determines the current driving period, the first set of output stage circuits includes a first output stage circuit (including switches T1 and T2), and the second set of output stage circuits includes a second output stage circuit (including switches T3 and T4). A path switch T5 is provided between the output terminals of the first and second output stage circuits. During a first time period, the controller controls the path switch T5 to be turned on (while simultaneously turning off the switches in the first and second output stage circuits), so that power from the first driving electrode connected to the first output stage circuit charges the second driving electrode connected to the second output stage circuit via the path switch T5. After the first time period, the controller controls the path switch T5 to be turned off. Subsequently, the controller can control the first switch T3 in the second output stage circuit to be turned on, so that the second driving electrode can be provided with a preset high-level voltage to continue charging, and control the second switch T2 of the first output stage circuit to be turned on to connect the first driving electrode to a low-voltage power supply terminal with a preset low level, so that the first driving electrode continues to discharge.

[0084] At the same time, as an example, combined with Figure 6AThe driving timing waveforms in the diagram provide a simple description of the output module's operation.

[0085] First, at time t0, the current driving period begins. The controller determines, based on the CDM code matrix, that the desired voltage value of the first driving electrode changes from the preset high level of the previous driving period to 0, indicating that the first driving electrode is expected to discharge. Simultaneously, the desired voltage value of the second driving electrode changes from 0 of the previous driving period to the preset high level, indicating that the second driving electrode is expected to charge. Therefore, the controller determines that the power on the first driving electrode can be used to charge the second driving electrode. Thus, at this time, the controller controls the path switch between the output terminals of the first output stage circuit and the second output stage circuit (for example, the high level is considered an effective level in the figure), allowing current to flow from the output terminal of the first output stage circuit to the output terminal of the second output stage circuit, and turns off the switch in the first output stage circuit and the second output stage circuit, meaning that there is no power interaction between the first output stage circuit and the driving electrode at this time.

[0086] Starting from time t0, all switches T1-T4 (assuming they are of the same type and conduct at high level) in the first and second output stage circuits are turned off, while path switch T5 is turned on. For example... Figure 6A The control signals T1-T4 shown are all low level, and the control signal T5 is high level. As the first driving electrode begins to charge the second driving electrode through the conducting path switch, the real-time voltage at the output terminal of the first output stage circuit (corresponding to the real-time voltage on the first driving electrode) begins to gradually decrease, while the real-time voltage at the output terminal of the second output stage circuit (corresponding to the real-time voltage on the second driving electrode) begins to gradually increase.

[0087] At time t1, the real-time voltage at the output terminal of the first output stage circuit drops to TX VDD / 2, while the real-time voltage at the output terminal of the second output stage circuit rises to TX VDD / 2. This means that the voltages on the first and second driving electrodes have reached equilibrium and can no longer continue charging and discharging, or that the voltage difference between them has met the threshold condition (e.g., within the threshold range). Therefore, the first time period corresponding to the charging and discharging process ends. At this time, the path switch T5 is turned off, and the corresponding control signal becomes an invalid level (low level). However, it is still necessary to charge the second driving electrode and discharge the first driving electrode. Therefore, at this time, the second switch T2 on the lower side of the first output stage circuit is turned on (the first switch T1 on the upper side remains off) to continue discharging the first driving electrode to the low-level power supply terminal with a preset low level. The first switch T3 on the upper side of the second output stage circuit is turned on (the second switch T4 on the lower side remains off) to continue charging the second driving electrode using the preset high level of the high-level power supply terminal, continuing until the end of the current driving time period.

[0088] It should be noted that, Figure 6A In this example, the charging and discharging process is illustrated using only two driving electrodes. Therefore, in this case, the ideal condition for charge-discharge equalization is that the voltage on the driving electrode is TX VDD / 2 (including the measurement error range). Furthermore, the ideal condition for charge-discharge equalization varies depending on the number of driving electrodes involved in the process. For example, when the ratio of discharging to charging driving electrodes is 1:2, the ideal condition for charge-discharge equalization is that the voltage on the driving electrode is TX VDD / 3 (including the measurement error range). Additionally, different conditions can be set to stop the charging and discharging process without requiring complete equalization. For example, the charging and discharging process can be set to a predetermined duration, or the charging and discharging process can be stopped when the voltage difference between the two driving electrodes is less than TX VDD / 10.

[0089] Subsequently, at time t2, the current driving period ends, and the next driving period becomes the new current driving period. At this time, the second driving electrode begins to discharge, and the first driving electrode begins to charge. Therefore, the path switch needs to be reversed relative to the conduction direction of the previous driving period to provide power from the second driving electrode to the first driving electrode. The driving timing of each switch in this process is similar to that of the previous driving period, so it will not be repeated here.

[0090] As another example, such as Figure 6B As shown, an output module includes four output stage circuits. For ease of description, the specific structure of the output stage circuits is omitted. The specific structure can be, for example, as shown below. Figure 3 As shown, or other available structures may be used. Figure 6B In this circuit, a path switch is set between each pair of output terminals of every two output stage circuits.

[0091] Figure 6B The driving principle of the output module shown in the figure and Figure 6AThe driving principle of the output module is similar. Assuming that the first set of output stage circuits includes first and second output stage circuits, and the second set of output stage circuits includes third and fourth output stage circuits, during a first time period, the controller controls the path switches between the output terminals of the first and third output stage circuits, between the output terminals of the first and fourth output stage circuits, between the output terminals of the second and third output stage circuits, and between the output terminals of the second and third output stage circuits, so that the power from the first driving electrode connected to the first and second output stage circuits charges the third and fourth driving electrodes connected to the third and fourth output stage circuits. After the first time period, the controller controls the path switches to turn off, and controls the first and second switches in the first to fourth output stage circuits to provide a preset high-level voltage to the third and fourth driving electrodes to continue charging them, and connects the first and second driving electrodes to a low-voltage power supply terminal with a preset low level, so that the first and second driving electrodes continue discharging.

[0092] Alternatively, in this case, where both the first and second output stage circuits include at least two output stage circuits and path switches are provided between each pair of output stage circuits, the controller can determine which two output stage circuits' output terminals' path switches are activated according to preset rules. Furthermore, it can make the driving electrodes to be discharged and the driving electrodes to be charged correspond one-to-one as much as possible to simplify the control logic. For example, it can be based on the positional distance of the connected driving electrodes, random combinations, and / or make the number of output stage circuits that charge and discharge the driving electrodes as evenly as possible.

[0093] For example, the controller controls the path switch between the output terminals of the first and third output stage circuits to turn on, so that the power from the first driving electrode connected to the first output stage circuit charges the third driving electrode connected to the third output stage circuit, and controls the path switch between the second and fourth output stage circuits to turn on, so that the power from the second driving electrode connected to the second output stage circuit charges the fourth driving electrode connected to the fourth output stage circuit; and after a first time period, the controller controls the path switches to turn off, and controls the first and second switches in each output stage circuit to provide a preset high-level voltage to the third and fourth driving electrodes to continue charging them, and connects the first and second driving electrodes to a low-voltage power supply terminal with a preset low level, so that the first and second driving electrodes continue to discharge.

[0094] Additionally, if in Figure 6BIn the case of the output module shown, if the drive signals output by the second and third output stage circuits still need to maintain the level of the previous drive stage in the current drive stage, and the first group of output stage circuits only includes the fourth output stage circuit, and the second group of output stage circuits only includes the first output stage circuit, then the drive electrodes connected to the second and third output stage circuits do not need to be charged by other drive electrodes or discharged to other drive electrodes. Therefore, only the path switch from the fourth output stage circuit to the output terminal of the first output stage circuit is turned on.

[0095] Figure 6B The driving timing of the switches and path switches in the output stage circuit shown can also be determined according to... Figure 6A The driving timing can be derived similarly, as long as the charging and discharging process between the driving electrodes is carried out in the first time period of the current driving period.

[0096] As mentioned earlier, in each output module, a path switch is required between each pair of output terminals of the output stage circuit, and this path switch can provide a bidirectional current flow path. Therefore, each of the path switches set between the output terminals of each pair of output stage circuits is either a single bidirectional conducting switch (a single switching device) or a pair of unidirectional conducting switches (two switching devices) with opposite conduction directions. Optionally, the path switch can be various types of transistors.

[0097] The above is for reference only. Figure 5-6B An example of how a path switch can be used to provide a charging and discharging path in a touch driver device is described below, in conjunction with... Figures 7A-7D Another example of using a path switch and a charging shared bus to provide a charging / discharging path is described.

[0098] like Figures 7A-7D As shown, the touch driver 400 may further include: at least one charging shared bus, and the output terminal of each output stage circuit included in each output module is connected to the at least one charging shared bus via a corresponding path switch, that is, each output terminal is switchably connected to each charging shared bus via at least one path switch. Each path switch is a single bidirectional switch or a pair of unidirectional switches with opposite conduction directions. Although the output terminal of each output stage circuit is connected to the charging shared bus via a corresponding path switch, it can still be considered that there is a path switch between the output terminals of every two output stage circuits.

[0099] exist Figure 7AThe diagram illustrates an example where there is one charging shared bus and two output stage circuits in each output module. The output terminals OUTPUT1 and OUTPUT2 of both the first and second output stage circuits are connected to the charging shared bus via a path switch (although shown as one, it refers to a single bidirectional switch or a pair of unidirectional switches with opposite conduction directions). When the first drive electrode connected to the output terminal OUTPUT1 of the first output stage circuit needs to charge the second drive electrode connected to the output terminal OUTPUT2 of the second output stage circuit, the path switch corresponding to the first output stage circuit is turned on in the first direction, and the path switch corresponding to the second output stage circuit is turned on in the second direction (or both path switches can be turned on bidirectionally simultaneously). The charging current flows through the charging shared bus, and vice versa.

[0100] exist Figure 7B The diagram illustrates an example where the number of charging shared buses is two (e.g., more buses can reduce path loss and / or speed up charging and discharging). Each output module includes two output stage circuits. The output terminals OUTPUT1 and OUTPUT2 of both the first and second output stage circuits are connected to the two charging shared buses via two path switches. When the first drive electrode connected to OUTPUT1 of the first output stage circuit needs to charge the second drive electrode connected to OUTPUT2 of the second output stage circuit, the two path switches corresponding to the first output stage circuit are turned on in the first direction, and the two path switches corresponding to the second output stage circuit are turned on in the second direction (or simultaneously turning on these path switches bidirectionally is also feasible). The charging current flows through these two charging shared buses, and vice versa.

[0101] exist Figure 7C The diagram illustrates an example where the number of charging shared buses is one, and each output module includes four output stage circuits. The output terminals OUTPUT1-4 of the first to fourth output stage circuits are all connected to this charging shared bus via a path switch. When the first set of drive electrodes connected to the output terminals of the first set of output stage circuits (e.g., the first and second output stage circuits) needs to be charged to the second set of drive electrodes connected to the output terminals of the second set of output stage circuits (e.g., the third and fourth output stage circuits), the path switches corresponding to the first and second output stage circuits are turned on in the first direction, and the path switches corresponding to the third and fourth output stage circuits are turned on in the second direction (or it is also possible to simultaneously turn on these path switches bidirectionally), allowing the charging current to flow through the charging shared bus, and vice versa.

[0102] exist Figure 7DThe diagram illustrates an example with two shared charging buses and four output stage circuits in each output module. The output terminals OUTPUT1-4 of the first to fourth output stage circuits are each connected to one of the two shared charging buses via two path switches. When the first set of drive electrodes connected to the output terminals of the first set of output stage circuits (e.g., the first and second output stage circuits) needs to be charged to the second set of drive electrodes connected to the output terminals of the second set of output stage circuits (e.g., the third and fourth output stage circuits), the two path switches corresponding to the first and second output stage circuits are turned on in the first direction, and the two path switches corresponding to the third and fourth output stage circuits are turned on in the second direction (or it is also possible to simultaneously turn on these path switches bidirectionally), allowing the charging current to flow through the shared charging bus, and vice versa.

[0103] Reference Figures 7A-7D In the described implementation, all driving electrodes that need to release power and all driving electrodes that need to be charged are charged using a charging shared bus to achieve charge balancing, thereby realizing the charging and discharging process. Therefore, it is no longer necessary to set path switches and select charging and discharging combinations at the output terminals of every two output stage circuits. This reduces the number of path switches, which is beneficial for circuit layout and circuit size, and can also reduce the complexity of control logic.

[0104] The above references Figure 4-7D In the described embodiments, the charging and discharging process between the driving electrodes is performed within a first time period. This first time period can be preset; for example, based on experience, the duration between the start point of each driving period and a predetermined time point after the start point can be used as the duration of the first time period. Alternatively, the first time period can also be determined based on the charging and discharging process between the driving electrodes. For example, it can be determined based on a first set of voltage values ​​at the output terminals of a first set of output stage circuits (for discharging the first set of driving electrodes) and a second set of voltage values ​​at the output terminals of a second set of output stage circuits (for charging the second set of driving electrodes). For example, a comparison unit can be provided, and the controller determines the duration of the first time period based on the comparison result of the comparison unit for these voltage values ​​and the control logic.

[0105] The following combination Figure 8-13 This application describes a schematic structure of a comparison unit in a touch driving device for a touch panel according to an embodiment of the present application, wherein the comparison unit is used to determine the end of a first time period in which a charging and discharging process between driving electrodes is performed. The start point of the first time period is the start point of each driving period, for example, the rising or falling edge of a driving signal pulse.

[0106] It should be noted that the following is merely an exemplary description of the method of using a comparison unit to determine the end of the charging and discharging process (the end of the first time period) based on the voltage at the output terminal of the output stage circuit. However, those skilled in the art should understand that other methods or other configurations of the comparison unit may be used to determine the end of the charging and discharging process based on the voltage at the output terminal of the output stage circuit, and these methods do not depart from the scope of protection claimed in this application.

[0107] For example, in some implementations, the controller 420 may include multiple comparison units, each with one end representing the voltage value at the output of an output stage circuit and the other end representing a reference voltage value. The first time period ends when a sufficient number of output stage circuits have output voltage values ​​that satisfy a threshold condition (e.g., the difference is sufficiently small) with respect to the corresponding reference voltage value. The reference voltage value can be determined based on the ratio of the number of driving electrodes to be charged and discharged (to achieve charge / discharge balance), or any other threshold (without requiring charge / discharge balance).

[0108] For example, such as Figure 8 As shown, the first set of output stage circuits includes a first output stage circuit, and the second set of output stage circuits includes a second output stage circuit. The first and second output stage circuits share a charging / discharging path (either the switch between them is active, or switches connected to the charging shared bus are active). Figure 8 And the method for determining the first time period in the subsequent attached figures. Figure 6A The structure of the output module shown is used as an example for illustration, but it should be understood that it can be applied to other output modules (e.g., Figure 6B-7D The first voltage value at the output terminal of the first output stage circuit and the second voltage value at the output terminal of the second output stage circuit are compared with a reference voltage value (Vref, such as TX VDD / 2 or other preset reference value). The first time period ends when the difference between the two voltage values ​​and the corresponding reference voltage values ​​is within a threshold range. Of course, the first time period can also end when at least one of the two differences is within the threshold range, depending on the control logic design of the controller, which is not limited in this application.

[0109] However, this approach requires a power supply that accurately generates the reference voltage value, and when there are more output stage circuits in the output module (possibly with different ratios of the number of driving electrodes for charging and discharging), more reference voltage values ​​may be needed, which require power supply circuitry to provide, potentially increasing the complexity of the circuitry and control logic.

[0110] Therefore, in other embodiments of this application, the first set of voltage values ​​output by the first set of output stage circuits and the second set of voltage values ​​output by the second set of output stage circuits can be used as the inputs of the comparison unit, instead of using the reference voltage value.

[0111] For example, controller 420 may include at least one comparison unit. Each comparison unit compares one of the first set of voltage values ​​with a corresponding one of the second set of voltage values ​​and outputs a comparison result indicating whether the voltage difference between the one of the first set of voltage values ​​and the corresponding one of the second set of voltage values ​​meets a threshold condition (e.g., the voltage difference between the two is within a threshold range, or the voltage difference between the voltage division of one and the voltage of the other is within a threshold range, etc.), wherein controller 420 determines that the first time period ends when the number of comparison results indicating that the threshold condition is met is greater than or equal to a first predetermined number.

[0112] For example, such as Figure 9 As shown, the output terminals of every two output stage circuits of each output module are respectively connected to the two input terminals of a comparator unit. The controller 420 can determine the enabled comparator unit based on the determined on-path switch.

[0113] Optionally, the first preset quantity may be less than or equal to the quantity of the second group of voltage values, for example, half the quantity of the second group of voltage values. Alternatively, the first preset quantity may be, for example, half the quantity of the first group of voltage values. This application does not impose any limitations on this.

[0114] For example, Figure 9 The output module includes four output stage circuits. The first group of output stage circuits includes the first and second output stage circuits 415-1 to 415-2, and the second group of output stage circuits includes the third and fourth output stage circuits 415-1 to 415-2. A comparator unit is provided between the output terminals of every two output stage circuits (as mentioned above). Figure 6AAs shown, a path switch is also provided to implement the charging and discharging path. When the controller controls the path switch between the output terminals of the first output stage circuit and the third output stage circuit to be turned on (i.e., the first output stage circuit discharges to the third output stage circuit), and the path switch between the output terminals of the second output stage circuit and the fourth output stage circuit to be turned on (i.e., the second output stage circuit discharges to the fourth output stage circuit), the controller enables comparators Comp1 and Comp2. The two input terminals of comparator Comp1 are the voltage values ​​of the output terminals of the first and third output stage circuits, and the two input terminals of comparator Comp2 are the voltage values ​​of the output terminals of the second and fourth output stage circuits. When the voltage values ​​of the output terminals of the first and third output stage circuits meet the threshold condition (e.g., the voltage difference is within the threshold range) and the voltage values ​​of the output terminals of the second and fourth output stage circuits also meet the threshold condition (e.g., the voltage difference is within the threshold range), that is, when the number of comparison results that meet the threshold condition is 2 (equal to the number of the second group of voltage values), the controller can determine the end of the first time period according to the control logic design within the controller.

[0115] Of course, as mentioned earlier, the driving electrodes for charging and discharging do not have to be in a one-to-one correspondence; for example, Figure 9 In the first output stage circuit, when the driving electrode corresponding to the first output stage circuit can simultaneously charge the driving electrodes corresponding to the third and fourth output stage circuits, the controller needs to turn on the path switch between the output terminals of the first output stage circuit and the third and fourth output stage circuits, and activate the comparison unit connected between them. The second output stage circuit is similar. Then, based on the result of the comparison unit and the control logic design within the controller, the controller 420 can determine the end of the first time period.

[0116] Alternatively or additionally, a similar reference may be used where all output stage circuitry included in each output module is connected to at least one charging shared bus via a path switch. Figure 8 or Figure 9 The described method of setting up comparison units to determine the duration of the first time period can also be used, i.e., a comparison unit can be connected between every two output terminals, and the controller can enable some of the comparison units according to the on-path switches.

[0117] However, considering that in the case of a shared charging bus, the current during the charging and discharging process can flow between the output terminals of any two output stage circuits corresponding to the driving electrodes that are charging and discharging via the shared charging bus, and that the design parameters of each output stage circuit are similar, in some other embodiments of this application, instead of setting a comparison unit between the output terminals of every two output stage circuits, only a few or even one comparison unit is required.

[0118] For example, the controller includes at least one comparison unit, and one input terminal of each comparison unit is connected to the output terminal of the first representative output stage circuit in the first group of output stage circuits to obtain a first representative voltage value, and the other input terminal is connected to the output terminal of the second representative output stage circuit in the second group of output stage circuits to obtain a second representative voltage value, thereby obtaining at least one comparison result. When the number of comparison results indicating that the obtained first representative voltage value and the corresponding second representative voltage value satisfy a threshold condition is greater than or equal to a second preset number, the controller determines that the first time period ends.

[0119] like Figure 10 As shown, the touch driver includes a comparison unit Comp-t. Of course, depending on the number of output stage circuits in the output module, two or more comparison units can be provided, and the connection method between the input terminal of each comparison unit and the output terminal of the output stage circuit also varies. Figure 10 similar.

[0120] exist Figure 10 In this example, the output module includes four output stage circuits. The first group of output stage circuits includes first and second output stage circuits 415-1 to 415-2, and the second group of output stage circuits includes third and fourth output stage circuits 415-1 to 415-2. One input terminal of the comparison unit Comp-t is connected to the output terminal of the first representative output stage circuit in the first group of output stage circuits, and the other input terminal is connected to the output terminal of the second representative output stage circuit in the second group of output stage circuits. When the first representative voltage value at the output terminal of the first representative output stage circuit and the second representative voltage value at the output terminal of the second representative output stage circuit satisfy a threshold condition, the controller determines that the first time period has ended.

[0121] For example, the controller can pre-design a method for determining the first and second representative output stage circuits under different combinations of the output stage circuits in the first and second groups, as preset logic. In practical applications, after determining the first and second groups of output stage circuits, the first and second representative output stage circuits are determined according to the preset logic.

[0122] For example, the preset logic could include: if the first group of output stage circuits includes a first output stage circuit, and the second group of output stage circuits includes second to fourth output stage circuits, then the first representative output stage circuit is the first output stage circuit, and the second representative output stage circuit is the third output stage circuit; or, if the first group of output stage circuits includes first to second output stage circuits, and the second group of output stage circuits includes third to fourth output stage circuits, then the first representative output stage circuit is the first output stage circuit, and the second representative output stage circuit is the fourth output stage circuit; and so on. Of course, this is just an example, and the determination of the first and second representative output stage circuits under different possible combinations of output stage circuits can be pre-designed based on various factors.

[0123] In addition, when the controller includes more than one comparator unit, the determination of the output stage circuit under different possible combinations can be pre-designed in a similar way.

[0124] For example, when the number of comparison units is 2, the preset logic may include: If the first group of output stage circuits includes one first output stage circuit, and the second group of output stage circuits includes five second to sixth output stage circuits, then the representative output stage circuit in the first group of output stage circuits is the first output stage circuit, and serves as one input to each of comparison units 1 and 2; the two representative output stage circuits in the second group of output stage circuits are the third and fourth output stage circuits, and serve as the other input to each of comparison units 1 and 2. As another example, if the number of comparison units is 2, and the first group of output stage circuits includes the first to third output stage circuits, and the second group of output stage circuits includes the fourth to sixth output stage circuits, then the two representative output stage circuits in the first group of output stage circuits are the first and third output stage circuits, corresponding to comparison units 1 and 2 respectively; the two representative output stage circuits in the second group of output stage circuits are the fifth and sixth output stage circuits, corresponding to comparison units 1 and 2 respectively. Of course, this is just an example; the determination of the first and second representative output stage circuits under different possible combinations of output stage circuits can be pre-designed based on various factors.

[0125] For example, the charging / discharging speed of each output stage circuit can be pre-designed and determined based on the charging / discharging speed of its output terminal, and the charging / discharging speed can be determined based on previous operating records of these output stage circuits and / or system parameters. For example, the first representative output stage circuit mentioned above can be the one with the slowest discharging speed in the first group of output stage circuits, and the fourth representative output stage circuit can be the one with the slowest charging speed in the second group of output stage circuits. Optionally, the output stage circuits can be pre-sorted according to their charging / discharging speed and system parameters, and this order can be stored in memory. After the first and second groups of output stage circuits are determined, the slowest discharging and slowest charging output stage circuits in each of the first and second groups are determined according to this order, and these are used as representative output stage circuits.

[0126] Of course, other methods can also be used to determine the first representative output stage circuit and the second representative output stage circuit.

[0127] In this implementation, both inputs of each comparator unit need to be able to connect to each output stage circuit in the output module. In some examples, the outputs of all output stage circuits in the output module can be switched to the two inputs of each comparator unit via a one-to-many switching module, for example, using a multiplexer or multiplexer. This allows the controller to control which two output stage circuits each comparator unit's two inputs should be connected to by controlling the one-to-many switching module.

[0128] like Figure 11 As shown, each output stage circuit in the output module is connected to multiplexers S1 and S2 or multiplexers MUX1 and MUX2 (not shown). The outputs of multiplexers S1 and S2 or multiplexers MUX1 and MUX2 are respectively connected to the two input terminals of a comparator unit. The multiplexers S1 and S2 or multiplexers MUX1 and MUX2 are switched according to the controller, thereby providing the comparator unit with the first and second representative voltage values ​​of the output terminals of the two output stage circuits. Of course, this is merely an example; other switching methods are also feasible, and this application does not limit this.

[0129] Regarding the case where both ends of the comparator unit are connected to the output terminals of the output stage circuit, although most of the preceding descriptions pertain to the scenario where the charging and discharging process stops only after equalization is achieved between the driving electrodes used for charging and discharging, some other implementations may not require stopping the charging and discharging process only when the voltage values ​​of the discharging and charging driving electrodes are equal (i.e., the charging and discharging are completely equalized). For example, other conditions for determining the end of the first time period can be determined according to actual needs. For instance, in the case of one driving electrode discharging to another driving electrode, it is not necessary to determine the end of the first time period (and stop the charging and discharging process) only when both the first and second voltage values ​​on the discharging and charging driving electrodes are TX VDD / 2 (the error range is negligible). Instead, the end of the first time period can be determined even when there is still a certain difference between the first and second voltage values.

[0130] To this end, the comparison unit may include a scaling subunit for scaling the voltage value at one input terminal of the comparison unit, so as to compare the scaled voltage value with the voltage value at the other input terminal. The condition for determining the end of the first time period can be changed by a preset scaling ratio. Optionally, the scaling subunit may be a voltage divider circuit.

[0131] For example, Figure 12 A schematic structural diagram of a comparison unit including a scaling subunit is shown.

[0132] like Figure 12 As shown, the voltage V1 at the output terminal OUTPUTm of one output stage circuit is divided by a voltage divider circuit (e.g., resistors R1 and R2 connected in series) as a scaling subunit. The scaled voltage V1*R2 / (R1+R2) is used as one input of a comparator, and the voltage V2 at the output terminal OUTPUTn of another output stage circuit is used as the other input of the comparator. Thus, when the value of V1*R2 / (R1+R2) is almost the same as V2, the comparator outputs a comparison result indicating that the charging and discharging process between the corresponding drive electrodes of the two output stages has ended (the voltage difference meets the threshold condition). At this time, when V1 and V2 are not equal, the comparator outputs the comparison result.

[0133] According to other embodiments, the controller may include a number of comparison units equal to the number of charging shared buses, with each comparison unit corresponding to a specific charging shared bus. Each comparison unit has a first terminal connected to the corresponding charging shared bus to obtain a bus charging / discharging voltage value, and a second terminal to obtain a reference voltage value, thus obtaining at least one comparison result. The controller determines the end of the first time period when the number of comparison results indicating that the bus voltage value obtained from the corresponding charging shared bus satisfies a threshold condition with the reference voltage value is greater than or equal to a third predetermined number.

[0134] Optionally, the reference voltage value may be associated with the number of output stage circuits included in the first group of output stage circuits and the second group of output stage circuits.

[0135] For example, such as Figure 13 As shown, the first terminals of the two comparison units Comp12-1 and Comp12-2 are respectively connected to two charging shared buses, and the second terminals are respectively connected to voltage sources that provide reference voltage values. When the comparison result of at least one comparison unit indicates that the voltage difference between the bus voltage value and the reference voltage value Vref (for example, when the number of output stage circuits included in the first group of output stage circuits and the second group of output stage circuits is equal, Vref is TX VDD / 2) is sufficiently small (i.e., the third predetermined number is 1), the controller determines that the first time period ends.

[0136] Based on the above reference Figure 4-13 The aforementioned touch driving device has at least the following advantages: First, it modularizes multiple output stage circuits corresponding to multiple driving electrodes on the touch panel, thereby enabling the generation and control of driving signals for each output module; second, by setting path switches between driving electrodes, the charging and discharging process between driving electrodes can be performed, thereby reducing the power required by the touch driving device to supply to the driving electrodes and thus reducing power consumption; third, it uses a charging shared bus to perform charge balancing for all driving electrodes that need to release power and all driving electrodes that need to be charged, thereby realizing the charging and discharging process, thus eliminating the need to set path switches and selection at the output terminals of every two output stage circuits. Choosing the right charge / discharge combination can reduce the number of path switches, which is beneficial for circuit layout and size reduction, and can also reduce the complexity of control logic. This advantage is particularly evident in cases with more than two output stage circuits. Finally, in some embodiments, by setting the voltage value at the output terminal of the output stage circuit as the input of the comparison unit, there is no need to set one or more additional reference voltage sources, which simplifies the circuit design. At the same time, a scaling sub-unit is set in the comparison unit, which allows for flexible design of the conditions for terminating the charge / discharge process between the drive electrodes, without having to terminate the charge / discharge process between the drive electrodes only when the difference between the voltage values ​​of the charge / discharge drive electrodes is substantially the same (within the measurement error range).

[0137] According to another aspect of this application, a method for reference as described above is also provided. Figure 4-13 A method for a touch driving device for a touch panel is described.

[0138] Figure 14 A flowchart illustrating a method for a touch driving device for a touch panel according to an embodiment of this application is shown. The touch panel includes a plurality of driving electrodes and a plurality of sensing electrodes arranged in a cross configuration.

[0139] For example, in step S1410, a first set of output stage circuits and a second set of output stage circuits are determined according to the code division multiple access (CDM) code matrix, wherein a first set of drive signals at the output terminal of the first set of output stage circuits is expected to discharge the first set of drive electrodes, and a second set of drive signals at the output terminal of the second set of output stage circuits is expected to charge the second set of drive electrodes.

[0140] Alternatively, without the output stage circuit, in step S1410, a first group of driving electrodes and a second group of driving electrodes are determined according to the code division multiple access (CDM) code matrix, wherein the first group of driving electrodes are driving electrodes among a plurality of driving electrodes that are expected to be discharged in the current driving period, and the second group of driving electrodes are driving electrodes among a plurality of driving electrodes that are expected to be charged in the current driving period.

[0141] In step S1420, in response to the determination, control is used to charge the second set of driving electrodes with power from the first set of driving electrodes.

[0142] Optionally, the plurality of driving electrodes are divided into at least one group, each group corresponding to an output module, each output module including at least two output stage circuits, each output stage circuit outputting a driving signal to the connected driving electrode based on a driving control signal. Figure 14 The method shown is performed for each output module, that is, the code division multiple access (CDM) code matrix corresponds to each output module, and for each output module, the output terminal of the first set of output stage circuits is connected to the first set of drive electrodes, and the output terminal of the second set of output stage circuits is connected to the second set of drive electrodes.

[0143] Optionally, refer to the preceding reference Figure 4-13 Similarly, specifically, in step S1420, the first set of output stage circuits and the second set of output stage circuits are controlled to charge the second set of drive electrodes using the power from the first set of drive electrodes for a first time period. After the first time period, the first set of output stage circuits and the second set of output stage circuits are controlled to release the remaining power from the first set of drive electrodes to the low-level power supply terminal and continue to charge the second set of drive electrodes using the high-level power supply terminal.

[0144] For example, in order to enable the flow of current, at least one path switch is set between the output terminals of every two output stage circuits in the output stage circuits included in each output module. During a first time period, the controller disables the first group of output stage circuits and the second group of output stage circuits, and controls the conduction of at least a portion of the at least one path switch, so that the power from the first group of drive electrodes charges the second group of drive electrodes. After the first time period, the controller enables the conduction path between the output terminal of the first group of output stage circuits and the low-level power supply terminal, and the conduction path between the high-level power supply terminal and the output terminal of the second group of output stage circuits, and controls the deactivation of at least a portion of the at least one path switch.

[0145] Figure 14 Further details of the method shown are the same as or similar to those described above for touch driving devices for touch panels, and will not be repeated here as they have already been described above.

[0146] The following points need to be explained:

[0147] (1) The accompanying drawings of the embodiments of this application only involve the structures involved in the embodiments of this application. Other structures can be referred to the general design.

[0148] (2) Where there is no conflict, the embodiments of this application and the features in the embodiments can be combined with each other to obtain new embodiments.

[0149] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. The scope of protection of this application shall be determined by the scope of protection of the claims.

Claims

1. A touch driving apparatus for a touch sensor, wherein the touch sensor comprises a plurality of drive electrodes and a plurality of sense electrodes arranged in a cross pattern, the touch driving apparatus comprising: at least one output module, each output module comprising at least two output stage circuits, each output stage circuit having an output terminal for outputting a drive signal to a connected drive electrode; a controller configured to, for each output module, determine, according to a code division multiple access (CDMA) code matrix, a first group of output stage circuits and a second group of output stage circuits for a current drive period, wherein a first group of drive signals at the output terminals of the first group of output stage circuits are expected to discharge a first group of drive electrodes, and a second group of drive signals at the output terminals of the second group of output stage circuits are expected to charge a second group of drive electrodes; and in response to the determination, control charging of the second group of drive electrodes with power from the first group of drive electrodes for a first time period, the touch driving apparatus further comprising at least one comparison unit, wherein: each comparison unit compares one of a first group of voltage values at the output terminals of the first group of output stage circuits with a corresponding one of a second group of voltage values at the output terminals of the second group of output stage circuits, and outputs a comparison result indicating whether a voltage difference between the one of the first group of voltage values and the corresponding one of the second group of voltage values satisfies a threshold condition, wherein when a number of comparison results indicating satisfaction of the threshold condition is greater than or equal to a first predetermined number, the controller determines that the first time period ends. the controller controls the first group of output stage circuits and the second group of output stage circuits to:

2. The touch driving apparatus of claim 1, wherein, charge the second group of drive electrodes with power from the first group of drive electrodes for the first time period; and after the first time period elapses, release remaining power from the first group of drive electrodes to a low-level power supply terminal and charge the second group of drive electrodes with a high-level power supply terminal. at least one path switch arranged between the output terminals of each two of the at least two output stage circuits, wherein, during the first time period, the controller disables the first group of output stage circuits and the second group of output stage circuits, and controls at least a portion of the at least one path switch to be turned on, so that the second group of drive electrodes is charged with power from the first group of drive electrodes; and 3. The touch driving apparatus of claim 2, further comprising: after the first time period elapses, the controller enables a conduction path between the output terminals of the first group of output stage circuits and the low-level power supply terminal, and a conduction path between the high-level power supply terminal and the output terminals of the second group of output stage circuits, and controls the at least a portion of the at least one path switch to be turned off. at least one charge sharing bus, wherein the output terminal of each of the at least two output stage circuits is connected to the at least one charge sharing bus via a corresponding path switch, and each path switch is a single bidirectional conduction switch or a pair of unidirectional conduction switches with opposite conduction directions.

4. The touch driving apparatus of claim 3, further comprising: the output terminals of each two output stage circuits are connected to two input terminals of one comparison unit, respectively, ​ 5. The touch driving apparatus of claim 3, wherein, ​ The controller determines an enabled comparison unit according to the determined conductive path switch.

6. The touch driving apparatus of claim 1, wherein, The comparison unit includes a scaling subunit configured to scale a voltage value at a first input terminal of the comparison unit, and compare the scaled voltage value with a voltage value at a second input terminal.

7. The touch driving apparatus of claim 2 or 3, wherein, Each output stage circuit includes a first switch and a second switch connected in series between a high voltage power supply terminal and a low voltage power supply terminal, a connection node of the first switch and the second switch being connected to an output terminal of the output stage circuit, The controller turns off the first switch and the second switch of each output stage circuit in the first group of output stage circuits and the second group of output stage circuits during the first time period; and After the first time period, the controller turns on the first switch and turns off the second switch of each output stage circuit in the second group of output stage circuits to charge the drive electrode via the first switch using the high voltage power supply terminal, and turns on the second switch and turns off the first switch of each output stage circuit in the first group of output stage circuits to discharge the remaining power of the drive electrode to the low voltage power supply terminal via the second switch.

8. The touch driving apparatus of claim 1, wherein, The controller determines a desired drive signal corresponding to each drive electrode according to the CDM code matrix, wherein each desired drive signal includes a plurality of drive periods, and a length of each drive period is half of a period of the desired drive signal, For each drive period, the controller determines the first group of output stage circuits and the second group of output stage circuits based on the determined desired drive signal.

9. The touch driving apparatus of claim 1, wherein, The number of the at least one output module is a plurality, and Each output module is connected to a group of drive electrodes, and the number of the group of drive electrodes is the same as the number of output stage circuits included in the output module.

10. A touch drive apparatus for a touch sensor, wherein the touch sensor includes a plurality of drive electrodes and a plurality of sense electrodes arranged in a cross manner, the touch drive apparatus comprising: at least one output module, each output module including at least two output stage circuits, an output terminal of each output stage circuit being configured to output a drive signal to a connected drive electrode; a controller configured to, for each output module, determine a first group of output stage circuits and a second group of output stage circuits for a current drive period according to a code division multiple access (CDM) code matrix, wherein a first group of drive signals at output terminals of the first group of output stage circuits is expected to discharge a first group of drive electrodes, and a second group of drive signals at output terminals of the second group of output stage circuits is expected to charge a second group of drive electrodes; and in response to the determination, control charging of the second group of drive electrodes using power from the first group of drive electrodes for a first time period, wherein the touch drive apparatus further includes at least one charge sharing bus, and an output terminal of each of the at least two output stage circuits is connected to the at least one charge sharing bus via a corresponding path switch, wherein the touch drive apparatus further includes at least one comparison unit, and the at least one comparison unit is configured to compare a voltage value at a first input terminal of the comparison unit with a voltage value at a second input terminal of the comparison unit. The first input end of each comparison unit is connected to the output end of a first representative output stage circuit in the first group of output stage circuits to obtain a first representative voltage value, and the second input end is connected to the output end of a second representative output stage circuit in the second group of output stage circuits to obtain a second representative voltage value, to obtain at least one comparison result, and when the number of comparison results indicating that the obtained first representative voltage value and the corresponding one of the second representative voltage values meet a threshold condition is greater than or equal to a second predetermined number, the controller determines that the first time period ends; or The at least one comparison unit corresponds to the at least one charging sharing bus one by one, and the first end of each comparison unit is connected to the corresponding charging sharing bus to obtain a bus voltage value, and the second end obtains a reference voltage value, to obtain at least one comparison result, the reference voltage value being associated with the number of output stage circuits included in the first group of output stage circuits and the second group of output stage circuits; when the number of comparison results indicating that the bus voltage value obtained from the corresponding charging sharing bus and the reference voltage value meet a threshold condition is greater than or equal to a third predetermined number, the controller determines that the first time period ends.

11. A touch device, comprising: a touch panel including a plurality of drive electrodes and a plurality of sense electrodes arranged in a cross manner; the touch driving device of any one of claims 1-10, configured to provide a drive signal to a drive electrode on the touch panel.

12. A touch driving method for a touch sensor, the touch sensor including a plurality of drive electrodes and a plurality of sense electrodes arranged in a cross manner, the plurality of drive electrodes being divided into at least one group, each group corresponding to one output module, each output module including a number of output stage circuits equal to the number of drive electrodes in each group, The method comprises: for each output module, determining, according to a code division multiple access (CDMA) code matrix, a first group of output stage circuits and a second group of output stage circuits in a current driving period, wherein a first group of drive signals at the output ends of the first group of output stage circuits are expected to discharge a first group of drive electrodes, and a second group of drive signals at the output ends of the second group of output stage circuits are expected to charge a second group of drive electrodes; and in response to the determination, controlling charging of the second group of drive electrodes with power from the first group of drive electrodes for a first time period, wherein the touch driving method further comprises: comparing one of a first group of voltage values at the output ends of the first group of output stage circuits with a corresponding one of a second group of voltage values at the output ends of the second group of output stage circuits, and outputting a comparison result indicating whether a voltage difference between the one of the first group of voltage values and the corresponding one of the second group of voltage values meets a threshold condition, and determining that the first time period ends when the number of comparison results indicating that the threshold condition is met is greater than or equal to a first predetermined number.

13. The touch driving method of claim 12, further comprising: After the first time period, control releases remaining power from the first set of drive electrodes to a low-level power terminal, and continues charging the second set of drive electrodes with a high-level power terminal.

14. The touch driving method of claim 12, wherein, At least one path switch is arranged between the output terminals of each two output stage circuits included in each output module, wherein the control charging the second set of drive electrodes with power from the first set of drive electrodes further comprises: during the first time period, disabling the first set of output stage circuits and the second set of output stage circuits, and controlling at least a portion of the at least one path switch to be turned on, so that power from the first set of drive electrodes charges the second set of drive electrodes; and after the first time period, enabling the turned-on path between the output terminals of the first set of output stage circuits and the low-level power terminal, and the turned-on path between the high-level power terminal and the output terminals of the second set of output stage circuits, and controlling the at least a portion of the at least one path switch to be turned off.

15. A touch driving method for a touch sensor, the touch sensor comprising a plurality of drive electrodes and a plurality of sense electrodes arranged in a cross manner, the plurality of drive electrodes being divided into at least one group, each group corresponding to one output module, each output module comprising a same number of output stage circuits as the number of drive electrodes of each group, The method comprises: for each output module, determining, according to a code division multiple access (CDM) code matrix, a first set of output stage circuits and a second set of output stage circuits at a current driving period, wherein a first set of drive signals of the output terminals of the first set of output stage circuits are expected to discharge a first set of drive electrodes, and a second set of drive signals of the output terminals of the second set of output stage circuits are expected to charge a second set of drive electrodes; and in response to the determination, controlling charging the second set of drive electrodes with power from the first set of drive electrodes for a first time period, wherein the output terminal of each output stage circuit in the output module is connected to at least one charging sharing bus via a corresponding path switch, and the touch driving method further comprises: comparing a first representative voltage value of the output terminal of a first representative output stage circuit in the first set of output stage circuits and a second representative voltage value of the output terminal of a second representative output stage circuit in the second set of output stage circuits, obtaining at least one comparison result, and determining the first time period to end when a number of comparison results indicating that the obtained first representative voltage value and a corresponding one of the second representative voltage values satisfy a threshold condition is greater than or equal to a second predetermined number; or comparing a bus voltage value on each charging sharing bus with a reference voltage value associated with the number of output stage circuits included in the first set of output stage circuits and the second set of output stage circuits, obtaining at least one comparison result, and determining the first period to end when a number of comparison results indicating that the bus voltage value on the corresponding charging sharing bus and the reference voltage value satisfy a threshold condition is greater than or equal to a third predetermined number.

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