Driving system and driving circuit thereof

Abstract

The invention discloses a driving system and a driving circuit thereof, the driving system comprises a plurality of driving circuits, and each driving circuit is provided with a first end point and a second end point. The first end points of the driving circuits are jointly coupled to a first transmission bus, and the second end points of the driving circuits are jointly coupled to a second transmission bus. The plurality of driving circuits comprise a first driving circuit and a second driving circuit. The first driving circuit is used for outputting a first synchronization signal to the first transmission bus through the first end point. The second driving circuit is used for outputting a second synchronizing signal to the second transmission bus through the second end point while receiving the first synchronizing signal from the first transmission bus. Wherein the compensation time corresponding to the second driving circuit is calculated according to the output time point of the first synchronizing signal and the receiving time point of the second synchronizing signal.

Description

Technical Field

[0001] The present invention relates to a driving system and a driving circuit, and in particular to a driving system having a plurality of driving circuits for jointly driving a display screen. Background Art

[0002] As a data communication interface, touch screens have been widely used in various electronic products today, such as mobile phones, satellite navigation systems, monitors, laptops, etc. Touch screens are a user-friendly input device that not only meets the requirements of being used as a multi-level menu design, but also has the functions of a keyboard, a mouse, and user-friendly operation methods such as handwriting input. In particular, the feature of integrating input and output on the same interface (such as a screen) is something that other traditional input devices cannot achieve.

[0003] As the size and resolution of touch screens are gradually increasing, touch screens usually need to be driven by multiple driving circuits (such as driver integrated circuits), where each driving circuit is responsible for controlling the touch sensing and display operations of the corresponding area on the touch screen. In the touch sensing operation, the driving circuit can output a touch driving signal to the corresponding area, and the touch driving signal is usually a sine wave signal. If the touch driving signals of the two driving circuits are not synchronized, the received sensing signal may not be well demodulated. Summary of the invention

[0004] Therefore, the main purpose of the present invention is to provide a driving system and a driving circuit for controlling a touch screen, wherein each driving circuit can perform touch sensing through a synchronized timing.

[0005] An embodiment of the present invention discloses a driving system, which includes a plurality of driving circuits, wherein each driving circuit has a first terminal and a second terminal. The first terminal of each driving circuit in the plurality of driving circuits is commonly coupled to a first transmission bus, and the second terminal of each driving circuit in the plurality of driving circuits is commonly coupled to a second transmission bus. The plurality of driving circuits include a first driving circuit and a second driving circuit. The first driving circuit is used to output a first synchronization signal to the first transmission bus through the first terminal. The second driving circuit is used to output a second synchronization signal to the second transmission bus through the second terminal while receiving the first synchronization signal from the first transmission bus. Wherein, a corresponding compensation time of the second driving circuit is calculated according to an output time point of the first synchronization signal and a receiving time point of the second synchronization signal.

[0006] Another embodiment of the present invention discloses a driving system, which includes a plurality of driving circuits, wherein each driving circuit has a first terminal and a second terminal. The first terminal of each driving circuit in the plurality of driving circuits is commonly coupled to a first transmission bus, and the second terminal of each driving circuit in the plurality of driving circuits is commonly coupled to a second transmission bus. The plurality of driving circuits include a first driving circuit and at least one second driving circuit. Each second driving circuit in the at least one second driving circuit is used to generate a notification. The first driving circuit is used to perform the following steps: receiving the notification from each second driving circuit in the at least one second driving circuit; after receiving the notification from each second driving circuit in the at least one second driving circuit, outputting a confirmation signal through the first terminal; and after outputting the confirmation signal, starting a preset operation for sensing with a delay having a compensation time corresponding to the first driving circuit. The at least one second driving circuit also receives the confirmation signal through the first terminal, and after receiving the confirmation signal, starts the preset operation for sensing with a delay having a compensation time corresponding to the respective second driving circuit.

[0007] Another embodiment of the present invention discloses a first driving circuit, which is coupled to at least one second driving circuit. Each of the first driving circuit and the at least one second driving circuit has a first terminal and a second terminal. The first terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a first transmission bus, and the second terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a second transmission bus. The first driving circuit is used to perform the following steps: output a first synchronization signal to the first transmission bus through the first terminal; receive a second synchronization signal from the second transmission bus through the second terminal, wherein the second synchronization signal is output by the second driving circuit in the at least one second driving circuit at the same time when the second driving circuit in the at least one second driving circuit receives the first synchronization signal; and calculate a compensation time corresponding to the second driving circuit in the at least one second driving circuit according to an output time point of the first synchronization signal and a reception time point of the second synchronization signal.

[0008] Another embodiment of the present invention discloses a first driving circuit, which is coupled to at least one second driving circuit. Each of the first driving circuit and the at least one second driving circuit has a first terminal and a second terminal. The first terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a first transmission bus, and the second terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a second transmission bus. The first driving circuit is used to perform the following steps: receiving a notification from each of the at least one second driving circuit; after receiving the notification from each of the at least one second driving circuit, outputting a confirmation signal through the first terminal; and after outputting the confirmation signal, starting a preset operation for sensing with a delay having a compensation time corresponding to the first driving circuit.

[0009] Another embodiment of the present invention discloses a second driving circuit, which is coupled to a first driving circuit. Each of the first driving circuit and the second driving circuit has a first terminal and a second terminal. The first terminal of each of the first driving circuit and the second driving circuit is commonly coupled to a first transmission bus, and the second terminal of each of the first driving circuit and the second driving circuit is commonly coupled to a second transmission bus. The second driving circuit is used to perform the following steps: generate a notification; receive a confirmation signal from the first driving circuit through the first terminal, wherein the confirmation signal is generated in response to the notification; and after receiving the confirmation signal, start a preset operation for sensing with a delay having a compensation time corresponding to the second driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of a drive system.

[0011] Figure 2 The asynchronous problem that occurs in the touch sensing operation is shown.

[0012] Figure 3 Schematic diagram of calibration mode operation in a drive system with two integrated circuits.

[0013] Figure 4 Schematic diagram of calibration mode operation in a drive system with three integrated circuits.

[0014] Figure 5A Schematic diagram of synchronous mode operation in a drive system with two integrated circuits.

[0015] Figure 5B for Figure 5A FIG. 1 is a waveform diagram of the touch sensing operation of the master circuit and the slave circuit.

[0016] Fig. 6A Schematic diagram of synchronous mode operation in a drive system with three integrated circuits.

[0017] Figure 6B for Fig. 6A FIG. 1 is a waveform diagram of the touch sensing operation of the master circuit and the slave circuit.

[0018] Fig. 7A FIG. 1 is a schematic diagram of a driving system according to an embodiment of the present invention.

[0019] Figure 7B and Figure 7C Shown in Fig. 7A An exemplary correction mode operation is performed in a drive system.

[0020] Fig. 8A The embodiment of the present invention is shown in Fig. 7A A correction operation used in the drive system to achieve path delay.

[0021] Figure 8B and Figure 8C For Fig. 8A Waveform diagram of the synchronization signal at each endpoint under the delay time.

[0022] Fig. 9 An exemplary correction mode operation performed in another drive system is shown.

[0023] Fig. 10A The embodiment of the present invention is shown in Fig. 9 A correction operation used in the drive system to achieve path delay.

[0024] Fig. 10B For Fig. 10A Waveform diagram of the synchronization signal at each endpoint under the delay time.

[0025] Fig.11 Another exemplary calibration mode operation performed in a drive system is shown.

[0026] Fig.12 An exemplary synchronous mode operation performed in a drive system is shown.

[0027] Fig.13 FIG. 7 is a waveform diagram of the touch sensing operation and related notification and confirmation signals on each end point of the driving system.

[0028] Fig.14 for Fig. 9 Waveform diagram of touch sensing operation and related notification and confirmation signals on each endpoint of the driving system.

[0029] Fig.15Another exemplary synchronous mode operation performed in a drive system is shown.

[0030] Fig.16A Yet another exemplary synchronous mode operation performed in a drive system is shown.

[0031] Fig. 16B and Fig. 16C The figure is a waveform diagram of the touch sensing operation and the related notification and confirmation signals at each end of the driving system.

[0032] The reference numerals are described as follows:

[0033] 10, 30, 40, 70, 90 drive systems

[0034] 100 Touch screen

[0035] 102, 302, 402, 702, 902 main control circuit

[0036] 104, 304, 404, 406, 704, 706, 708, 710, 904, 906, 908, 910 slave circuits

[0038] 112 Sine Wave Generator Tx touch drive signal Rx touch sensing signal 122 Analog-to-digital converter 124 Digital Sine Wave Generator 126 Demodulator Rx_D demodulated signal TSHD_ANA Analog sensing start signal TSHD sensing start signal ANA_SET Analog settings M1, M2, S1, S2, M1_L, M2_L, M1_R, M2_R, S1_L, S2_L, S1_R, S2_R, S1_1, S2_1, S1_2, S2_2, S1_3, S2_3, S1_4, S2_4 endpoints

[0039] SYNC1, SYNC2, SYNC1_L, SYNC2_L, SYNC1_R, SYNC2_R synchronization signals NTF, NTF_L, NTF_R, NTF1~NTF4 notification CONF, CONF_L, CONF_R confirmation signals CT, CT_L, CT_R compensation time BUS1, BUS2 transmission bus PD Path Delay OFS offset value DETAILED DESCRIPTION

[0040] Figure 1 1 is a schematic diagram of a driving system 10. The driving system 10 includes a touch screen 100, a master driving circuit 102 and a slave driving circuit 104. In the present invention, the master driving circuit 102 and the slave driving circuit 104 can be implemented in an integrated circuit (IC) located in a chip, and are therefore referred to as a master integrated circuit (referred to as the master circuit) and a slave integrated circuit (referred to as the slave circuit) respectively below. The master circuit 102 and the slave circuit 104 can jointly control the operation of the touch screen 100, including touch sensing operation and display operation. The master circuit 102 and the slave circuit 104 are each responsible for controlling their corresponding area on the touch screen 100.

[0041] In detail, the master circuit 102 may include a sine wave generator 112 for outputting a sine wave signal to the touch screen 100 as a touch driving signal Tx. The slave circuit 104 may receive a touch sensing signal Rx from the touch screen 100 in response to the touch driving signal Tx of the master circuit 102. The slave circuit 104 may include an analog-to-digital converter (ADC) 122, a digital sine wave generator 124, and a demodulator 126. The ADC 122 may convert the received touch sensing signal Rx into a digital form, and the touch sensing signal Rx is then demodulated by another sine wave signal generated by the digital sine wave generator 124 to generate a sensing result, which may be used to indicate, for example, whether a touch gesture occurs and / or the touch signal strength.

[0042] The touch screen 100 may include a plurality of pixels configured as an array, which may be connected by horizontal gate lines and vertical data lines. The gate lines and the data lines must pass through the entire touch screen 100, including the area controlled by the master circuit 102 and the area controlled by the slave circuit 104. In addition, depending on the arrangement of the touch sensing pads, there may be a touch sensing pad located in the area controlled by the master circuit 102 connected to another touch sensing pad located in the area controlled by the slave circuit 104 on the panel. In this case, during touch sensing, a touch drive signal should preferably be output to the entire touch screen 100 through the master circuit 102 to avoid collisions between different touch drive signals from different driver integrated circuits. Then, the corresponding touch sensing signals are received from each area through the respective driver integrated circuits.

[0043] like Figure 1As shown, the touch driving signal Tx is output by the master circuit 102, and the corresponding touch sensing signal Rx is received by the slave circuit 104. The slave circuit 104 also uses a demodulation signal Rx_D generated by the digital sine wave generator 124 to demodulate the touch sensing signal Rx (through the demodulator 126). The demodulation signal Rx_D can also be a sine wave signal with the same frequency and amplitude as the touch driving signal Tx. In order to achieve an ideal sensing result, the demodulation signal Rx_D should be well synchronized with the touch driving signal Tx.

[0044] In a driving circuit (or driving integrated circuit), the touch sensing operation can be initialized using an analog sensing start signal TSHD_ANA and a sensing start signal TSHD. The analog sensing start signal TSHD_ANA can be used to indicate an analog setting, such as the setting of an analog front-end (AFE) circuit in the driving circuit. The sensing start signal TSHD can be used to indicate a digital setting, such as a preset operation for setting a touch sensing module in the driving circuit. Generally speaking, the time when the analog sensing start signal TSHD_ANA starts the analog setting is earlier than the time when the sensing start signal TSHD starts the digital setting.

[0045] In normal display mode, the analog sensing start signal TSHD_ANA and the sensing start signal TSHD of each driving circuit are received from the master driving circuit (i.e., the master circuit). Conventionally, due to the connection line load between the master circuit and other slave circuits, the start of the touch sensing operation may not be synchronized. For example, Figure 2 As shown, after the master circuit obtains the analog sensing start signal TSHD_ANA and the sensing start signal TSHD, it sends the analog sensing start signal TSHD_ANA and the sensing start signal TSHD to the slave circuit. Therefore, the master circuit obtains the analog sensing start signal TSHD_ANA and the sensing start signal TSHD earlier than the slave circuit. Therefore, the master circuit performs the analog setting (represented by ANA_SET, which is initiated by the reception of the analog sensing start signal TSHD_ANA) and the pre-setting operation (which is initiated by the reception of the sensing start signal TSHD) earlier than the slave circuit. The master circuit also performs the sensing and post-setting operation (postset operation) earlier than the slave circuit, resulting in the problem of asynchronous operation.

[0046] If the touch screen operates in the dark mode, each driving circuit can generate the analog sensing start signal TSHD_ANA and the sensing start signal TSHD. Traditionally, the master circuit and the slave circuit do not know each other's start touch sensing time, so their sensing start signals TSHD_ANA, TSHD and corresponding settings cannot be synchronized.

[0047] In order to synchronize the touch sensing operations of multiple driving circuits so that these driving circuits can jointly control a touch screen, these driving circuits can execute a calibration mode and a synchronization mode. In the calibration mode, the timing differences of the touch sensing operations between different driving circuits need to be calculated. In the synchronization mode, the sensing timing of each driving circuit is synchronized according to the timing information obtained in the calibration mode. For example, in Figure 2 In the case shown, the preset operation of the master circuit can be delayed by a compensation time calculated by the path delay between the master circuit and the slave circuit obtained in the calibration mode, so that the master circuit and the slave circuit can start the preset operation at the same time.

[0048] Figure 3 Schematic diagram of calibration mode operation in a driving system 30 having two integrated circuits, the driving system 30 includes a master circuit 302 and a slave circuit 304. The master circuit 302 and the slave circuit 304 each include a synchronization controller, which can be implemented in a timing controller of the driving circuit. The master circuit 302 includes two terminals M1 and M2, and the slave circuit 304 includes two terminals S1 and S2. The terminal M1 of the master circuit 302 is connected to the terminal S1 of the slave circuit 304, and the terminal M2 of the master circuit 302 is connected to the terminal S2 of the slave circuit 304.

[0049] like Figure 3 As shown, in the calibration mode, the master circuit 302 first outputs a first synchronization signal SYNC1 through the terminal M1 and starts a timer. The first synchronization signal SYNC1 is then transmitted to the terminal S1 of the slave circuit 304. When the slave circuit 304 receives the first synchronization signal SYNC1, the slave circuit 304 can output a second synchronization signal SYNC2 through the terminal S2 accordingly. The second synchronization signal SYNC2 is then transmitted to the terminal M2 of the master circuit 302. When the master circuit 302 receives the second synchronization signal SYNC2, the master circuit 302 stops the timer and records its timing result. The timing result of the timer indicates the path delay between the master circuit 302 and the slave circuit 304, wherein the path delay represents the round-trip propagation time, including the propagation time from the master circuit 302 to the slave circuit and the propagation time from the slave circuit 304 back to the master circuit 302. Then, the master circuit 302 can calculate a compensation time according to the path delay. Assuming that the path length between endpoints M1 and S1 is the same as the path length between endpoints M2 and S2, the compensation time is approximately equal to half of the path delay.

[0050] In one embodiment, the recording and calculation operations of the timer may be performed in the synchronization controller included in the master circuit 302 and the slave circuit 304, such as Figure 3 shown.

[0051] It is worth noting that the calibration mode operation can also be applied to more than 2 driver circuits. Figure 4 Schematic diagram of calibration mode operation in a driving system 40 having three integrated circuits, the driving system 40 includes a master control circuit 402 and two slave circuits 404 and 406. Similarly, the master control circuit 402 and the slave circuits 404 and 406 each include a synchronous controller for performing calibration operations. The master control circuit 402 includes four terminals, two of which are connected to the slave circuit 404, and two of which are connected to the slave circuit 406. The slave circuit 404 includes two terminals S1_L and S2_L, which are connected to the terminals M1_L and M2_L, respectively. The slave circuit 406 includes two terminals S1_R and S2_R, which are connected to the terminals M1_R and M2_R, respectively.

[0052] In a similar manner, the master circuit 402 can output a first left synchronization signal SYNC1_L to the slave circuit 404 through the terminal M1_L, and the slave circuit 404 can return a second left synchronization signal SYNC2_L to the master circuit 402 through the terminal S2_L. The master circuit 402 can use a timer to record the output time point of the first left synchronization signal SYNC1_L and the reception time point of the second left synchronization signal SYNC2_L, and calculate the corresponding path delay and compensation time of the slave circuit 404 accordingly. Similarly, the master circuit 402 can also output a first right synchronization signal SYNC1_R to the slave circuit 406 through the terminal M1_R, and the slave circuit 406 can return a second right synchronization signal SYNC2_R to the master circuit 402 through the terminal S2_R. The master circuit 402 may also use a timer to record the output time point of the first right synchronization signal SYNC1_R and the receiving time point of the second right synchronization signal SYNC2_R, and calculate the corresponding path delay and compensation time of the slave circuit 406 accordingly.

[0053] Figure 5A A schematic diagram of synchronous mode operation in a drive system having two integrated circuits, which is Figure 3 Take the drive system 30 in FIG. 1 as an example. Figure 5B The waveform diagram of the touch sensing operation of the master circuit 302 and the slave circuit 304, wherein the synchronous mode can be executed during a touch sensing period. When the touch screen controlled by the master circuit 302 and the slave circuit 304 is to perform touch sensing, the master circuit 302 and the slave circuit 304 can obtain the sensing start signal TSHD_ANA and TSHD. The analog sensing start signal TSHD_ANA indicates the start of the analog setting (ANA_SET), and the sensing start signal TSHD is used to start the preset operation for touch sensing.

[0054] More specifically, the master circuit 302 may first determine whether the slave circuit 304 is ready for touch sensing. For example, when the slave circuit 304 receives or obtains the sensing start signal TSHD, it may send a notification NTF to the master circuit 302 through the terminal S2. When the master circuit 302 receives the notification NTF and obtains the sensing start signal TSHD through the terminal M2, it may send a confirmation signal CONF to the slave circuit 304 through the terminal M1. After the confirmation signal CONF is sent, the master circuit 302 then starts the preset operation for touch sensing with a delay having a compensation time CT (which can be obtained in the calibration mode), wherein the compensation time CT is approximately equal to half of the path delay between the master circuit 302 and the slave circuit 304, as described above. When the slave circuit 304 receives the confirmation signal CONF through the terminal S1, the slave circuit 304 may immediately start the preset operation for touch sensing. By setting the compensation time CT appropriately, the master circuit 302 and the slave circuit 304 can start the preset operation at the same time to perform touch sensing synchronously.

[0055] It is worth noting that the synchronous mode operation can also be applied to more than two driver circuits. Fig. 6A A schematic diagram of synchronous mode operation in a drive system having three integrated circuits, which is Figure 4 Take the drive system 40 in FIG. 1 as an example. Figure 6B Waveform diagram of touch sensing operation of the master circuit 402 and the slave circuits 404 and 406, wherein the synchronization mode can be performed during a touch sensing period. In this example, the master circuit 402 can obtain a compensation time CT_L corresponding to the slave circuit 404 and a compensation time CT_R corresponding to the slave circuit 406 in the calibration mode.

[0056] Similarly, when the touch screen controlled by the master circuit 402 and the slave circuits 404 and 406 is to perform touch sensing, the master circuit 402 and the slave circuits 404 and 406 can obtain the sensing start signals TSHD_ANA and TSHD. The analog sensing start signal TSHD_ANA indicates the start of the analog setting (ANA_SET), and the sensing start signal TSHD is used to start the preset operation for touch sensing. The slave circuit 404 can send a notification NTF_L to the master circuit 402 through the terminal S2_L when receiving or obtaining the sensing start signal TSHD, and the slave circuit 406 can send a notification NTF_R to the master circuit 402 through the terminal S2_R when receiving or obtaining the sensing start signal TSHD. When the master circuit 402 receives the notification NTF_L through the terminal M2_L, receives the notification NTF_R through the terminal M2_R, and obtains the sensing start signal TSHD, it can send a confirmation signal CONF_L to the slave circuit 404 through the terminal M1_L, and send a confirmation signal CONF_R to the slave circuit 406 through the terminal M1_R. After the confirmation signals CONF_R and CONF_L are sent, the master circuit 302 then starts the preset operation for touch sensing with a delay according to the compensation times CT_L and CT_R obtained in the calibration mode. When the slave circuits 404 and 406 receive the confirmation signals CONF_L and CONF_R through the terminals S1_L and S1_R, respectively, the slave circuits 404 and 406 can immediately start the preset operation for touch sensing. Through the appropriate delay of the compensation times CT_L and CT_R, the master circuit 402 and the slave circuits 404 and 406 can start the preset operation at the same time to perform touch sensing synchronously.

[0057] It is worth noting that if the compensation times CT_L and CT_R used for the slave circuits 404 and 406 are different, the master circuit 402 may adjust the output time points of the confirmation signals CONF_L and CONF_R. Figure 6B As shown, the compensation time CT_R is greater than the compensation time CT_L, which means that the transmission path on the right side of the master circuit 402 may be longer than the transmission path on the left side of the master circuit 402. Therefore, the master circuit 402 outputs the confirmation signal CONF_R to the right slave circuit 406 earlier than the time when it outputs the confirmation signal CONF_L to the left slave circuit 404, so that the confirmation signals CONF_L and CONF_R arrive at the corresponding slave circuits 404 and 406 at the same time.

[0058] In one embodiment, the start time of the preset operation of each driver integrated circuit can be further manually fine-tuned or delayed to achieve a more optimized synchronization efficiency.

[0059] Based on the above-mentioned calibration mode and synchronization mode operations, the present invention proposes a novel driving system that can support the joint operation of more than three driving circuits to jointly control a touch screen. In some embodiments of the present invention, the driving system may include more than three driving circuits, one of which may be set as a master circuit, and the other driving circuits may be set as slave circuits. In other words, the driving system includes one master circuit and more than two slave circuits.

[0060] Fig. 7A Schematic diagram of a driving system 70 according to an embodiment of the present invention. The driving system 70 includes 5 driving circuits, including 1 master circuit 702 and 4 slave circuits 704, 706, 708 and 710. Each driving circuit has two terminals. More specifically, the master circuit 702 has two terminals M1 and M2, the slave circuit 704 has two terminals S1_1 and S2_1, the slave circuit 706 has two terminals S1_2 and S2_2, the slave circuit 708 has two terminals S1_3 and S2_3, and the slave circuit 710 has two terminals S1_4 and S2_4. Each terminal can be an input / output port of an integrated circuit for implementing the driving circuit. The terminals M1, S1_1, S1_2, S1_3 and S1_4 are coupled to a transmission bus BUS1, and the terminals M2, S2_1, S2_2, S2_3 and S2_4 are coupled to a transmission bus BUS2. In this example, a command line is also coupled to each drive circuit for communication between the drive circuits. In another embodiment, the command line may be omitted. The master control circuit 702 and the slave circuits 704-710 may each include a synchronization controller for performing calibration and synchronization operations in each drive circuit. The transmission buses BUS1 and BUS2 may be coupled to the synchronization controllers within the master control circuit 702 and the slave circuits 704-710.

[0061] In the driving system 70 , the master control circuit 702 is disposed in the middle, two slave circuits 704 and 706 are located on the left side of the master control circuit 702 , and another two slave circuits 708 and 710 are located on the right side of the master control circuit 702 .

[0062] Through the connection method of the driving system 70, a closed loop can be formed between every two driving circuits. For example, through the transmission buses BUS1 and BUS2, the master circuit 702 can form a closed loop with any slave circuit 704-710. A slave circuit (such as 704) can also form a closed loop with another slave circuit (such as 706) through the transmission buses BUS1 and BUS2. In this case, the path delay between any two driving circuits can be obtained. In addition, through the synchronization signal transmitted between the two driving circuits, the path delay of another driving circuit between the two driving circuits can also be obtained. In other words, multiple path delays between different driving circuits can be obtained in one calibration operation. In this way, the calibration mode operation can be performed in any appropriate manner to obtain the required path delay and calculate the corresponding compensation time.

[0063] Figure 7B 2 shows an exemplary calibration mode operation performed in the drive system 70. Figure 7B As shown, the master control circuit 702 can be used as the starting point of signal transmission to measure the corresponding path delays of the left slave circuits 704 and 706. More specifically, the master control circuit 702 can first output a first left synchronization signal SYNC1_L to the transmission bus BUS1 through the terminal M1, and start a timer at the same time. The first left synchronization signal SYNC1_L is then transmitted on the transmission bus BUS1. When the leftmost slave circuit 704 receives the first left synchronization signal SYNC1_L from the transmission bus BUS1, the slave circuit 704 can output a second left synchronization signal SYNC2_L to the transmission bus BUS2 through the terminal S2_1. The second left synchronization signal SYNC2_L can be transmitted on the transmission bus BUS2 and then received by the master control circuit 702. The master control circuit 702 can stop the timer when receiving the second left synchronization signal SYNC2_L. In this way, the master control circuit 702 can obtain the path delay between the master control circuit 702 and the slave circuit 704 according to the timing result of the timer, which records the time difference between the output time point of the first left synchronization signal SYNC1_L and the reception time point of the second left synchronization signal SYNC2_L. Then, according to the path delay, the master control circuit 702 can calculate and obtain the corresponding compensation time of the slave circuit 704.

[0064] In one embodiment, the value of the path delay may be divided by 2 to obtain a compensation time for the master circuit 702 or the slave circuit 704, so as to be used in the synchronization mode to synchronize the sensing time of the master circuit 702 and the slave circuit 704. In addition, the compensation time may be further manually adjusted or fine-tuned to achieve an optimized synchronization result.

[0065] The first left synchronization signal SYNC1_L and the second left synchronization signal SYNC2_L may also be used to calibrate the slave circuit 706. More specifically, the first left synchronization signal SYNC1_L transmitted on the transmission bus BUS1 and the second left synchronization signal SYNC2_L transmitted on the transmission bus BUS2 may also be received by the slave circuit 706. When the slave circuit 706 receives the first left synchronization signal SYNC1_L from the transmission bus BUS1 through the terminal S1_2, it may start a timer. Subsequently, when the slave circuit 706 receives the second left synchronization signal SYNC2_L from the transmission bus BUS2 through the terminal S2_2, it may stop the timer. Therefore, the timer of the slave circuit 706 records the time difference between the receiving time point of the first left synchronization signal SYNC1_L and the receiving time point of the second left synchronization signal SYNC2_L, which is equivalent to the path delay between the slave circuits 704 and 706.

[0066] Then, the slave circuit 706 may send the recorded timer information to the master circuit 702 (e.g., via a command line). Based on the information from the slave circuit 706, the master circuit 702 may obtain the path delay between the slave circuits 704 and 706. Alternatively or additionally, the slave circuit 706 may store the recorded timer information for use in a subsequent synchronization mode.

[0067] Thus, the master circuit 702 can obtain the compensation time corresponding to the slave circuits 704 and 706 located on the left side of the master circuit 702 in one calibration operation. In this calibration operation, a synchronization signal is output to the transmission bus BUS1 and a synchronization signal is output to the transmission bus BUS2.

[0068] In a similar manner, another transfer may be performed to calibrate slave circuits 708 and 710 located to the right of master circuit 702, such as Figure 7CAs shown. The master control circuit 702 may first output a first right synchronization signal SYNC1_R to the transmission bus BUS1 through the terminal M1, and simultaneously start a timer. The first right synchronization signal SYNC1_R is then transmitted on the transmission bus BUS1. When the slave circuit 710 on the far right receives the first right synchronization signal SYNC1_R from the transmission bus BUS1, the slave circuit 710 may output a second right synchronization signal SYNC2_R to the transmission bus BUS2 through the terminal S2_4. The second right synchronization signal SYNC2_R may be transmitted on the transmission bus BUS2, and then received by the master control circuit 702, and the master control circuit 702 may stop the timer when receiving the second right synchronization signal SYNC2_R. In this way, the master control circuit 702 may obtain the path delay between the master control circuit 702 and the slave circuit 710 according to the timing result of the timer, which records the time difference between the output time point of the first right synchronization signal SYNC1_R and the reception time point of the second right synchronization signal SYNC2_R. Next, according to the path delay, the master circuit 702 can calculate and obtain the corresponding compensation time of the slave circuit 710 .

[0069] In one embodiment, the path delay value may be divided by 2 to obtain the corresponding compensation time of the slave circuit 710, which is used to synchronize the sensing time of the master circuit 702 and the slave circuit 710 in the synchronization mode. In addition, the compensation time may also be further manually adjusted or fine-tuned to achieve an optimized synchronization result.

[0070] The first right synchronization signal SYNC1_R and the second right synchronization signal SYNC2_R may also be used to calibrate the slave circuit 708. More specifically, the first right synchronization signal SYNC1_R transmitted on the transmission bus BUS1 and the second right synchronization signal SYNC2_R transmitted on the transmission bus BUS2 may also be received by the slave circuit 708. When the slave circuit 708 receives the first right synchronization signal SYNC1_R from the transmission bus BUS1 through the terminal S1_3, it may start a timer. Subsequently, when the slave circuit 708 receives the second right synchronization signal SYNC2_R from the transmission bus BUS2 through the terminal S2_3, it may stop the timer. Therefore, the timer of the slave circuit 708 records the time difference between the receiving time point of the first right synchronization signal SYNC1_R and the receiving time point of the second right synchronization signal SYNC2_R, which is equivalent to the path delay between the slave circuits 708 and 710.

[0071] Then, the slave circuit 708 may send the recorded timer information to the master circuit 702 (e.g., via a command line). Based on the information from the slave circuit 708, the master circuit 702 may obtain the path delay between the slave circuits 708 and 710. Alternatively or additionally, the slave circuit 708 may store the recorded timer information for use in a subsequent synchronization mode.

[0072] Thus, the master circuit 702 can obtain the compensation time corresponding to the slave circuits 708 and 710 located on the right side of the master circuit 702 in another calibration operation. In this calibration operation, a synchronization signal is output to the transmission bus BUS1 and a synchronization signal is output to the transmission bus BUS2.

[0073] It can be seen that the path delays of multiple driving circuits can be obtained in one calibration operation. Only two calibration operations are needed to completely obtain the compensation time information of all driving circuits in the driving system 70.

[0074] Fig. 8A FIG. 1 shows a correction operation for obtaining path delay in a driving system 70 according to an embodiment of the present invention, wherein the value of the delay time is marked on the corresponding transmission bus path. Figure 8B and Figure 8C is the waveform diagram of the synchronization signal at each endpoint under these delay times, where: Figure 8B The operation of calibrating the slave circuits 704 and 706 located on the left side is described. Figure 8C The operation of correcting the slave circuits 708 and 710 located on the right side is described. Figure 8B and Figure 8C In the embodiment, the synchronization signals SYNC1_L, SYNC1_R, SYNC2_L and SYNC2_R are all pulse signals, but those skilled in the art should understand that the implementation method of the signal is not limited thereto.

[0075] like Figure 8BAs shown, the master control circuit 702 first outputs the first left synchronization signal SYNC1_L through the terminal M1 and starts a timer. The first left synchronization signal SYNC1_L can be transmitted through the transmission bus BUS1 and arrive at the terminal S1_2 of the slave circuit 706 after a delay time of 2. At this time, the slave circuit 706 starts a timer in response to the reception of the first left synchronization signal SYNC1_L. Then, the first left synchronization signal SYNC1_L continues to be transmitted through the transmission bus BUS1 and arrives at the terminal S1_1 of the slave circuit 704 after another delay time of 2. When the slave circuit 704 receives the first left synchronization signal SYNC1_L, it can return the second left synchronization signal SYNC2_L through the terminal S2_1. The second left synchronization signal SYNC2_L can be transmitted through the transmission bus BUS2 and arrive at the terminal S2_2 of the slave circuit 706 after a delay time of 2. At this time, the slave circuit 706 stops the timer in response to the reception of the second left synchronization signal SYNC2_L. The timer of slave circuit 706 can then record the path delay (expressed as PD) between slave circuits 704 and 706, which is equal to 4.

[0076] Then, the second left synchronization signal SYNC2_L continues to be transmitted through the transmission bus BUS2, and arrives at the terminal M2 of the master control circuit 702 after another delay time 2. At this time, the master control circuit 702 stops the timer in response to the reception of the second left synchronization signal SYNC2_L. The timer of the master control circuit 702 can record the path delay between the master control circuit 702 and the leftmost slave circuit 704, which is equal to 8.

[0077] The above calibration operation is for the slave circuits 704 and 706 on the left side. Therefore, the slave circuits 708 and 710 on the right side can ignore the synchronization signals SYNC1_L and SYNC2_L, or regard them as don't care signals.

[0078] Based on the value of the timer, the compensation time required between the slave circuits 704 and 706 can be calculated as 4 / 2=2, and the compensation time required between the slave circuit 704 and the master circuit 702 can be calculated as 8 / 2=4. Therefore, the corresponding driving circuit can use this compensation time information in the subsequent synchronization mode.

[0079] Figure 8C Another correction operation is shown to correct the slave circuits 708 and 710 located on the right. Figure 8CAs shown, the master circuit 702 first outputs the first right synchronization signal SYNC1_R through the terminal M1 and starts a timer. The first right synchronization signal SYNC1_R can be transmitted through the transmission bus BUS1 and arrive at the terminal S1_3 of the slave circuit 708 after a delay time of 1. At this time, the slave circuit 708 starts a timer in response to the reception of the first right synchronization signal SYNC1_R. Then, the first right synchronization signal SYNC1_R continues to be transmitted through the transmission bus BUS1 and arrives at the terminal S1_4 of the slave circuit 710 after another delay time of 1. When the slave circuit 710 receives the first right synchronization signal SYNC1_R, it can return the second right synchronization signal SYNC2_R through the terminal S2_4. The second right synchronization signal SYNC2_R can be transmitted through the transmission bus BUS2 and arrive at the terminal S2_3 of the slave circuit 708 after a delay time of 1. At this time, the slave circuit 708 stops the timer in response to the reception of the second right synchronization signal SYNC2_R. The timer of slave circuit 708 may then record the path delay between slave circuits 708 and 710 , which is equal to 2.

[0080] Then, the second right synchronization signal SYNC2_R continues to be transmitted through the transmission bus BUS2, and arrives at the terminal M2 of the master control circuit 702 after another delay time 1. At this time, the master control circuit 702 stops the timer in response to the reception of the second right synchronization signal SYNC2_R. The timer of the master control circuit 702 can record the path delay between the master control circuit 702 and the rightmost slave circuit 710, which is equal to 4.

[0081] The above correction operation is for the slave circuits 708 and 710 on the right side. Therefore, the slave circuits 704 and 706 on the left side can ignore the synchronization signals SYNC1_R and SYNC2_R, or regard them as don't care signals.

[0082] Based on the value of the timer, the compensation time required between the slave circuits 708 and 710 can be calculated as 2 / 1 = 1, and the compensation time required between the slave circuit 710 and the master circuit 702 can be calculated as 4 / 2 = 2. Therefore, the corresponding driving circuit can use this compensation time information in the subsequent synchronization mode.

[0083] In this example, the compensation time for the left slave circuits 704 and 706 can be obtained in one calibration operation, and the compensation time for the right slave circuits 708 and 710 can be obtained in another calibration operation. If the path delay of the left slave circuit is asymmetric with the path delay of the right slave circuit, an offset value can be further used to modify or adjust the compensation time to synchronize the slave circuits on both sides.

[0084] More specifically, if Figure 8B and Figure 8C As shown, the maximum path delay on the left (i.e., the path delay between the master circuit 702 and the leftmost slave circuit 704) is equal to 8, while the maximum path delay on the right (i.e., the path delay between the master circuit 702 and the rightmost slave circuit 710) is equal to 4. Since the two path delays are not equal, an additional offset value is required to compensate for the difference. In one embodiment, an offset value of 2 may be added to the compensation time for the right slave circuits 708 and 710, thereby achieving synchronization between the right slave circuit and the left slave circuit.

[0085] It is worth noting that in the drive system, the drive circuit can also be arranged in another way. For example, the main control circuit does not need to be located at the center of the drive system. Fig. 9 An exemplary calibration mode operation performed in another driving system 90 is shown, and the driving system 90 includes a master control circuit 902 and four slave circuits 904, 906, 908 and 910, which are coupled together through transmission buses BUS1 and BUS2. The master control circuit 902 and the slave circuits 904-910 are coupled to the transmission bus BUS1 through terminals M1 and S1_1-S1_4, respectively, and are coupled to the transmission bus BUS2 through terminals M2 and S2_1-S2_4, respectively. The implementation of the driving system 90 is similar to the driving system 70, except that the master control circuit 902 is the leftmost driving circuit, and therefore, the slave circuits 904-910 are all located on the right side of the master control circuit 902. Similarly, the master control circuit 902 and the slave circuits 904-910 can each include a synchronization controller for performing calibration and synchronization operations in each driving circuit. The transmission buses BUS1 and BUS2 may be coupled to the synchronization controllers inside the master circuit 902 and the slave circuits 904 ˜ 910 .

[0086] In addition, in the embodiment of Fig. 7, the transmission of the synchronization signal starts from the master circuit, but the present invention is not limited thereto. In another embodiment, the transmission of the synchronization signal may start from any slave circuit.

[0087] Fig. 9The transmission of the synchronization signal starts from the operation of the slave circuit 910. The slave circuit 910 can output a first synchronization signal SYNC1 to the transmission bus BUS2 and start a timer at the same time. When the master circuit 902 receives the first synchronization signal SYNC1, the master circuit 902 can output a second synchronization signal SYNC2 to the transmission bus BUS1. The second synchronization signal SYNC2 is then received by the slave circuit 910, and the slave circuit 910 can stop the timer when receiving the second synchronization signal SYNC2. In this way, the slave circuit 910 can obtain the path delay between the slave circuit 910 and the master circuit 902, so as to calculate the compensation time. Then, the slave circuit 910 can store the compensation time information and / or send the compensation time information to the master circuit 902, so as to be used for timing synchronization in the subsequent synchronization mode. Similarly, the slave circuits 904, 906 and 908 can also receive the first synchronization signal SYNC1 and the second synchronization signal SYNC2, and use the timer to record the reception time difference to obtain the corresponding path delay and compensation time.

[0088] Therefore, in Fig. 9 In an implementation manner, the compensation time information of all driving circuits can be completely obtained in one calibration operation. In one embodiment, the master control circuit can collect the compensation time information from each slave circuit through the command line.

[0089] Fig. 10A FIG. 1 shows a correction operation for obtaining path delay in a driving system 90 according to an embodiment of the present invention, wherein the value of the delay time is marked on the corresponding transmission bus path. Fig. 10B The waveform diagram of the synchronization signal at each end point under these delay times is used to illustrate the operation of calibrating each slave circuit. Fig. 10B In the embodiment, the synchronization signals SYNC1 and SYNC2 are both pulse signals, but those skilled in the art should understand that the implementation method of the signal is not limited thereto.

[0090] like Fig. 10BAs shown, the slave circuit 910 first outputs the first synchronization signal SYNC1 through the terminal S2_4 and starts a timer. The first synchronization signal SYNC1 can be transmitted through the transmission bus BUS2, and arrives at the terminal S2_3 of the slave circuit 908 after the delay time 1, then arrives at the terminal S2_2 of the slave circuit 906 after the delay time 1, then arrives at the terminal S2_1 of the slave circuit 904 after the delay time 2, and then arrives at the terminal M2 of the master circuit 902 after the delay time 2. The slave circuits 908, 906 and 904 respectively start a timer to record the reception time of the first synchronization signal SYNC1. When the master circuit 902 receives the first synchronization signal SYNC1, it can return the second synchronization signal SYNC2 through the terminal M1. The second synchronization signal SYNC2 can be transmitted through the transmission bus BUS1, and arrive at the slave circuits 904, 906, 908 and 910 in sequence after respective delay times. The slave circuits 904 , 906 , 908 and 910 respectively stop the timers to record the receiving time of the second synchronization signal SYNC2 .

[0091] In this way, the corresponding path delay can be obtained. In detail, the slave circuit 904 can obtain the path delay between the master circuit 902 and the slave circuit 904, which is equal to 4. The slave circuit 906 can obtain the path delay between the master circuit 902 and the slave circuit 906, which is equal to 8. The slave circuit 908 can obtain the path delay between the master circuit 902 and the slave circuit 908, which is equal to 10. The slave circuit 910 can obtain the path delay between the master circuit 902 and the slave circuit 910, which is equal to 12. Therefore, based on the obtained path delay information, the compensation time between any two driving circuits can be easily obtained. For example, the master circuit 902 can collect path delay information from each slave circuit 904-910, and calculate the compensation time for the master circuit 902 and each slave circuit 904-910 accordingly; or, each slave circuit 904-910 can calculate the compensation time according to the path delay respectively. The detailed calculation method is similar to the description in the previous paragraph and will not be repeated here.

[0092] In order to achieve accurate calibration results, the states of the input and output ports (i.e., endpoints) coupled to the transmission buses BUS1 and BUS2 should be well controlled. Each endpoint on the transmission buses BUS1 and BUS2 can be switched between an input state and an output state, and the resistance and capacitance load of each transmission bus is significantly affected by the input / output state of the endpoint to which it is connected. The resistance and capacitance load further affects the propagation speed of the signal, which is related to the measured path delay. As mentioned above, the calculation of the compensation time is to divide the path delay by 2. For this calculation method to be feasible, the path must remain symmetrical during the transmission of the first synchronization signal and the second synchronization signal. In other words, the overall input and output state of the transmission bus BUS1 when transmitting the corresponding synchronization signal should be the same as the overall input and output state of the transmission bus BUS2 when transmitting the corresponding synchronization signal.

[0093] For example, in Figure 7B In the driving system 70 shown, when the master circuit 702 transmits the first left synchronization signal SYNC1_L, the terminal M1 of the master circuit 702 is set to the output state, and the other terminals S1_1 to S1_4 coupled to the transmission bus BUS1 are set to the input state. In this case, during the transmission of the first left synchronization signal SYNC1_L, there is 1 output port and 4 input ports on the transmission bus BUS1. When the slave circuit 704 transmits the second left synchronization signal SYNC2_L, the terminal S2_1 of the slave circuit 704 is set to the output state, and the other terminals M2 and S2_2 to S2_4 coupled to the transmission bus BUS2 are set to the input state. In this case, during the transmission of the second left synchronization signal SYNC2_L, there is 1 output port and 4 input ports on the transmission bus BUS2. Therefore, the overall input / output state on the transmission bus BUS1 is the same as the overall input / output state on the transmission bus BUS2 to achieve path symmetry. In this way, the compensation time can be accurately calculated by dividing the path delay by 2.

[0094] In the above embodiment, only a small amount of synchronization signals need to be transmitted to complete the calibration, thus saving the time spent in the calibration mode. It should be noted that the calibration method proposed in the above description paragraph is only an exemplary embodiment of the present invention. In another embodiment, in the calibration mode, the calibration operation can also be performed only between the two driving circuits. For example, Fig.11 Another exemplary calibration mode operation performed in the drive system 70 is shown. Fig.11As shown, the master circuit 702 may output a first synchronization signal SYNC1 to the transmission bus BUS1 and start a timer at the same time. The first synchronization signal SYNC1 is transmitted to the slave circuit 710, and at the same time, the slave circuit 710 returns a second synchronization signal SYNC2 to the transmission bus BUS2. The second synchronization signal SYNC2 is then transmitted to the master circuit 702. When the master circuit 702 receives the second synchronization signal SYNC2, it may stop the timer and obtain the path delay between the master circuit 702 and the slave circuit 710. Then, the master circuit 702 may divide the path delay by 2 to obtain the corresponding compensation time of the slave circuit 710. The master circuit 702 may then repeat the same calibration operation for each of the other slave circuits 704, 706 and 708 to obtain their corresponding path delays and compensation times.

[0095] Similarly, during the transmission of the synchronization signal, the overall input / output state of the transmission bus BUS1 when transmitting the first synchronization signal SYNC1 should be the same as the overall input / output state of the transmission bus BUS2 when transmitting the second synchronization signal SYNC2, so as to achieve path symmetry. For example, the endpoints of the driving circuit used to output the synchronization signal are set to the output state, and the endpoints of other driving circuits on the same transmission bus are all set to the input state. Therefore, if a transmission bus is coupled to 5 driving circuits, there will be 1 output port and 4 input ports on the transmission bus.

[0096] In another embodiment, the synchronization signal may also be initiated from a slave circuit instead of the master circuit. For example, in the driving system 70, the slave circuit 710 may output a first synchronization signal SYNC1 to the transmission bus BUS1 and simultaneously start a timer. When the master circuit 702 receives the first synchronization signal SYNC1, the master circuit 702 returns a second synchronization signal SYNC2 to the transmission bus BUS2. Then, the slave circuit 710 stops the timer upon receiving the second synchronization signal SYNC2 to obtain the corresponding path delay of the master circuit 702. The slave circuit 710 may repeat the same calibration operation for each of the other slave circuits 704, 706 and 708 to obtain their corresponding path delays. In one embodiment, the slave circuit 710 may transmit the path delay information to the master circuit 702 (e.g., via a command line), and then the master circuit 702 may calculate the compensation time for the master circuit 702 and each of the slave circuits 704-710 accordingly.

[0097] The obtained compensation time for each driving circuit may be further applied in a synchronization mode to synchronize the sensing time of touch sensing between different driving circuits, as described below.

[0098] In the synchronous mode, the driving circuit can perform touch sensing. The touch sensing is started by a sensing start signal (such as Figure 2 Before the synchronous operation, each driver circuit can obtain its own corresponding compensation time, which can be calculated according to the path delay in the calibration mode and transmitted to the target driver circuit through the command line.

[0099] In synchronous operation, each slave circuit may generate a notification upon receiving the sensing start signal TSHD, which is used to indicate that the slave circuit is ready for touch sensing. When the master circuit obtains the sensing start signal TSHD and receives the notification from each slave circuit, the master circuit may output a confirmation signal through a transmission bus. After outputting the confirmation signal, the master circuit starts a preset operation for touch sensing with a delay having a corresponding compensation time of the master circuit. The confirmation signal may be transmitted to each slave circuit through the transmission bus, that is, each slave circuit may receive the confirmation signal through its endpoint coupled to the transmission bus. After receiving the confirmation signal, the slave circuit starts a preset operation for touch sensing with a delay having a corresponding compensation time. The preset operation of each driving circuit (including the master circuit and each slave circuit) may be performed using a specific delay time corresponding to each driving circuit. Through appropriate delay control, each driving circuit may start the preset operation at the same time to achieve synchronization of the touch sensing operation.

[0100] For ease of explanation, the operation of the synchronous mode is described here using the same drive system. Fig.12 An exemplary synchronous mode operation performed in the driving system 70 is shown, wherein each driving circuit can be coupled to other driving circuits via transmission buses BUS1 and BUS2. First, when the touch screen is to perform touch sensing, each driving circuit 702-710 can obtain a sensing start signal TSHD. When each slave circuit 704-710 obtains the sensing start signal TSHD, it can generate a notification NTF1-NTF4 respectively.

[0101] Notifications NTF1-NTF4 may be implemented in any appropriate manner. In this example, endpoints S2_1-S2_4 coupled to the transmission bus BUS2 are pre-positioned at a low level. When the slave circuits 704-710 obtain the sensing start signal TSHD, the corresponding endpoints S2_1-S2_4 may be converted from a low level to a high level. More specifically, when the slave circuit 704 receives its sensing start signal TSHD, it may pull up the high end point S2_1 to generate notification NTF1; when the slave circuit 706 receives its sensing start signal TSHD, it may pull up the high end point S2_2 to generate notification NTF2; when the slave circuit 708 receives its sensing start signal TSHD, it may pull up the high end point S2_3 to generate notification NTF3; when the slave circuit 710 receives its sensing start signal TSHD, it may pull up the high end point S2_4 to generate notification NTF4.

[0102] The main control circuit 702 can monitor the transmission bus BUS2 to determine whether the terminal M2 is pulled high to receive the notifications NTF1-NTF4. When the terminals S2_1-S2_4 are all pulled high, that means all notifications NTF1-NTF4 have been output, the main control circuit 702 can observe that the terminal M2 is pulled high.

[0103] In one embodiment, the terminals S2_1 to S2_4 may be implemented by an open-drain structure, wherein the slave circuits 704 to 710 may output a notification by releasing a pull-down component on the corresponding terminal. Therefore, if all pull-down components coupled to the transmission bus BUS2 are released, the level of the transmission bus BUS2 and the terminal M2 may be pulled high.

[0104] When the master control circuit 702 receives the notifications NTF1-NTF4 and obtains the sensing start signal TSHD, the master control circuit 702 may output a confirmation signal CONF via the transmission bus BUS1. After outputting the confirmation signal CONF, the master control circuit 702 initiates a preset operation for touch sensing with a delay having a corresponding compensation time of the master control circuit 702, wherein the compensation time may be equal to the maximum path delay corresponding to the farthest slave circuit.

[0105] Then, the confirmation signal CONF is sequentially received by the slave circuits 704-710. After receiving the confirmation signal, each slave circuit 704-710 starts the preset operation for touch sensing with a delay having a corresponding compensation time of the respective slave circuit. Through the appropriate compensation time, each driving circuit (including the master circuit 702 and the slave circuits 704-710) can start the preset operation at the same time to synchronously perform touch sensing.

[0106] In one embodiment, in a driving system having a master circuit and one or more slave circuits, a touch driving signal may be provided by the master circuit, and each driving circuit receives a touch sensing signal from a corresponding area on the touch screen. The synchronized touch sensing operation enables each driving circuit to receive and process the touch sensing signal in a timing synchronized with the touch driving signal output by the master circuit. For example, a demodulation signal generated by each slave circuit that can be used to demodulate the touch sensing signal may be synchronized with the touch driving signal output by the master circuit, thereby being synchronized with the touch sensing signal received by each slave circuit.

[0107] It is worth noting that Fig. 8A The delay time implementation shown can also be applied to the synchronous mode used to perform touch sensing. Fig. 8A Matching Fig.13 As shown, Fig.13 FIG. 7 is a waveform diagram of the touch sensing operation and related notification and confirmation signals at each end of the driving system 70. Fig.13 As shown, the touch sensing operation starts with an analog setting (ANA_SET) and a preset operation, wherein the analog setting is initiated by receiving an analog sensing start signal TSHD_ANA. Fig.13 The analog sensing start signal TSHD_ANA is omitted.

[0108] In this example, the transmission bus BUS2 can be used to transmit notifications NTF1-NTF4, wherein the transition from low to high represents the output of the corresponding notification. Fig.13 As shown, when each slave circuit 704-710 obtains the sensing start signal TSHD, it can pull up the corresponding endpoints S2_1-S2_4 coupled to the transmission bus BUS2 to output corresponding notifications NTF1-NTF4. After all other endpoints coupled to the transmission bus BUS2 are pulled up, the endpoint M2 of the master circuit 702 is also pulled up, which means that all slave circuits are ready for touch sensing.

[0109] Then, the master control circuit 702 may output a confirmation signal CONF to the transmission bus BUS1 through the terminal M1, wherein the confirmation signal CONF is represented by a pulse (or a rising edge of a pulse). The master control circuit 702 then starts a preset operation after a delay of a compensation time, wherein the compensation time may be calculated by the maximum path delay of the master control circuit 702 obtained in the calibration mode.

[0110] In this example, after the calibration operation on the left, the master circuit 702 (and / or the slave circuits 704-706) can obtain a path delay between 702 and 704 equal to 8 and a path delay between 704 and 706 equal to 4. After the calibration operation on the right, the master circuit 702 (and / or the slave circuits 708-710) can obtain a path delay between 702 and 710 equal to 4 and a path delay between 710 and 708 equal to 2. The maximum path delay (expressed as PD) for the master circuit 702 is 8, so the compensation time (expressed as CT) for the master circuit 702 can be calculated to obtain 8 / 2=4, as shown in Fig.13 shown.

[0111] In addition, since the path delay of the left slave circuits 704 and 706 is greater than the path delay of the right slave circuits 708 and 710, an offset value (expressed as OFS) is added to the compensation time for the right slave circuits 708 and 710. In this example, the offset value is equal to the difference between the path delay between 702 and 704 and the path delay between 702 and 710 divided by 2, that is, (8-4) / 2=2.

[0112] The confirmation signal CONF output by the master circuit 702 may be received by the slave circuits 704 to 710 in sequence. When the slave circuit 708 receives the confirmation signal CONF, it may start the preset operation after delaying a compensation time plus an offset value. The actual compensation time for the slave circuit 708 is 3, which is equal to the path delay divided by 2 plus the offset value. When the slave circuit 710 receives the confirmation signal CONF, it may start the preset operation after delaying a compensation time equal to the offset value 2, which is the delay difference between the left and right sides. When the slave circuit 706 receives the confirmation signal CONF, it may start the preset operation after delaying a compensation time, and the compensation time for the slave circuit 706 is equal to the path delay divided by 2, that is, 4 / 2=2. When the slave circuit 704 receives the confirmation signal CONF, since the slave circuit 704 has the largest path delay corresponding to the master circuit 702 and receives the confirmation signal CONF the slowest, it may immediately start the preset operation without any delay.

[0113] like Fig.13 As shown, through proper delay control, the master circuit 702 and the slave circuits 704 ˜ 710 can start the preset operation for touch sensing at the same time to synchronously perform touch sensing.

[0114] In another embodiment, Fig. 10A The delay time implementation shown can also be applied to the synchronous mode used to perform touch sensing. Fig. 10A Matching Fig.14 As shown, Fig.14is a waveform diagram of the touch sensing operation and related notification and confirmation signals at each end of the driving system 90. Fig.14 As shown, the touch sensing operation starts with an analog setting (ANA_SET) and a preset operation, wherein the analog setting is initiated by receiving an analog sensing start signal TSHD_ANA. Fig.14 The analog sensing start signal TSHD_ANA is omitted.

[0115] In this example, the transmission bus BUS2 can be used to transmit notifications NTF1-NTF4, wherein the transition from low to high represents the output of the corresponding notification. Fig.14 As shown, when each slave circuit 904-910 obtains the sensing start signal TSHD, the corresponding terminals S2_1-S2_4 coupled to the transmission bus BUS2 can be pulled high to output corresponding notifications NTF1-NTF4. After all other terminals coupled to the transmission bus BUS2 are pulled high, the terminal M2 of the master circuit 902 is also pulled high, which means that all slave circuits are ready for touch sensing.

[0116] Then, the master control circuit 902 may output a confirmation signal CONF to the transmission bus BUS1 through the terminal M1, wherein the confirmation signal CONF is represented by a pulse (or a rising edge of a pulse). The master control circuit 902 then starts a preset operation after a delay of a compensation time, wherein the compensation time may be calculated by the maximum path delay of the master control circuit 902 obtained in the calibration mode.

[0117] In this example, after the calibration operation, the master circuit 902 (and / or the slave circuits 904-910) can obtain a path delay between 902 and 910 equal to 12, a path delay between 904 and 910 equal to 8, a path delay between 906 and 910 equal to 4, and a path delay between 908 and 910 equal to 2. The maximum path delay for the master circuit 902 is 12, so the compensation time for the master circuit 902 can be calculated to be 12 / 2=6, as Fig.14 shown.

[0118] It is worth noting that in this example, only one-side calibration operation is performed in the calibration mode, and therefore, the calculation of the compensation time does not require any offset value.

[0119] The confirmation signal CONF output by the master circuit 902 may be received by the slave circuits 904 to 910 in sequence. When the slave circuit 904 receives the confirmation signal CONF, it may start the pre-set operation after a delay of a compensation time, and the compensation time for the slave circuit 904 is equal to the path delay divided by 2, that is, 8 / 2=4. When the slave circuit 906 receives the confirmation signal CONF, it may start the pre-set operation after a delay of a compensation time, and the compensation time for the slave circuit 906 is equal to the path delay divided by 2, that is, 4 / 2=2. When the slave circuit 908 receives the confirmation signal CONF, it may start the pre-set operation after a delay of a compensation time, and the compensation time for the slave circuit 908 is equal to the path delay divided by 2, that is, 2 / 2=1. When the slave circuit 910 receives the confirmation signal CONF, since the slave circuit 910 has the largest path delay corresponding to the master circuit 902 and receives the confirmation signal CONF the slowest, it may immediately start the pre-set operation without any delay.

[0120] like Fig.14 As shown, through appropriate delay control, the master circuit 902 and the slave circuits 904 ˜ 910 can start the preset operation for touch sensing at the same time to synchronously perform touch sensing.

[0121] In the above embodiment, the slave circuit can send the notification via a transmission bus, but the implementation of the notification is not limited thereto. In another embodiment, the slave circuit can also send the notification via a command line coupled between the master circuit and the slave circuit.

[0122] Fig.15 Another exemplary synchronous mode operation performed in the drive system 70 is shown, wherein each drive circuit is coupled to other drive circuits via transmission buses BUS1 and BUS2 and a command line. In this example, the slave circuits 704-710 can send notifications to the master circuit 702 via the command line.

[0123] First, the master circuit 702 may receive a notification from each slave circuit 704-710 via a command line. For example, the master circuit 702 may read the status of each slave circuit 704-710 via a command line to ensure that each slave circuit 704-710 is ready for touch sensing. Fig.15As shown, the arrows on the command line indicate that the master control circuit 702 reads the status of each slave circuit 704-710, where the status can represent a notification. Alternatively, the slave circuits 704-710 can send a signal carrying a notification to the master control circuit 702 through the command line. When the master control circuit 702 knows that all slave circuits 704-710 are ready and obtain the sensing start signal TSHD, the master control circuit 702 can output a confirmation signal CONF through the transmission bus BUS1, and then start the preset operation after a delay of a compensation time. The confirmation signal CONF is transmitted through the transmission bus BUS1 and is received by the slave circuits 704-710 in sequence. After receiving the confirmation signal CONF, each slave circuit 704-710 starts the preset operation with a delay with a respective compensation time. Through appropriate delay control, the master control circuit 702 and the slave circuits 704-710 can start the preset operation at the same time to perform touch sensing synchronously.

[0124] As described above, the touch sensing operation can be initialized using the analog sensing start signal TSHD_ANA and the digital sensing start signal TSHD. To simplify the touch sensing process, one or both of the sensing start signal TSHD_ANA and TSHD can be omitted. For example, in one embodiment, the confirmation signal provided by the main control circuit can be used to indicate the start of the preset operation, replacing the function of the sensing start signal TSHD.

[0125] Fig.16A FIG. 7 shows another exemplary synchronous mode operation performed in the driving system 70, wherein the sensing start signal TSHD is omitted. When the touch screen controlled by the master circuit 702 and the slave circuits 704-710 is to perform touch sensing, each slave circuit 704-710 can output a corresponding notification NTF1-NTF4 to the master circuit 702, and the master circuit 702 can correspondingly output a confirmation signal CONF to the transmission bus BUS1 through the terminal M1. The notification NTF1-NTF4 can be transmitted via the transmission bus BUS2 (e.g., Fig.16A ), or can be transmitted using a command line (such as Fig.15 ). The master circuit 702 then starts the preset operation after a delay of a compensation time. The confirmation signal CONF can be transmitted through the transmission bus BUS1 and received by the slave circuits 704-710 in sequence. After receiving the confirmation signal CONF, each slave circuit 704-710 starts the preset operation with a delay having a respective compensation time. Through appropriate delay control, the master circuit 702 and the slave circuits 704-710 can start the preset operation at the same time to perform touch sensing synchronously.

[0126] The relevant waveforms are as follows Fig. 16B, which shows the touch sensing operation of the driving system 70 and the related confirmation signals output or received at each end. Similarly, the touch sensing operation starts with an analog setting (ANA_SET) and a preset operation. In this example, the analog setting is initiated by receiving an analog sensing start signal TSHD_ANA. For simplicity, Fig. 16B The analog sensing start signal TSHD_ANA is omitted. The preset operation is started after obtaining the confirmation signal CONF plus an appropriate delay time, without generating the sensing start signal TSHD.

[0127] like Fig. 16B As shown, when each slave circuit 704-710 is ready for touch sensing, it can generate corresponding notifications NTF1-NTF4. The notifications NTF1-NTF4 can be received by the master circuit 702 through the transmission bus BUS2 or the command line, as described in the above embodiment. The subsequent operations and related compensation times are all related to Fig.13 The situation shown is the same and will not be repeated here.

[0128] Fig. 16C FIG. 1 is a waveform diagram of the touch sensing operation and related notification and confirmation signals at each end of the driving system 70, wherein the analog sensing start signal TSHD_ANA and the sensing start signal TSHD are omitted. In this case, the analog setting (ANA_SET) is started after obtaining the confirmation signal CONF and adding an appropriate delay. The compensation time of the delay is Fig.13 Through appropriate delay control, the master circuit 702 and the slave circuits 704-710 can start analog setting at the same time, so the preset operation after analog setting can also be performed at the same time, thereby performing touch sensing synchronously.

[0129] It is noteworthy that the purpose of the present invention is to provide a method for synchronizing touch sensing operations, which can be performed in a drive system having multiple drive circuits for jointly controlling a touch screen. The method includes a calibration mode and a synchronization mode. In the calibration mode, the path delay between the drive circuits can be measured to calculate the compensation time for each drive circuit. The calibration mode can be performed at any time point before the touch sensing operation. In one embodiment, the calibration mode can be performed periodically and / or when the drive system is idle.

[0130] The compensation time obtained in the calibration mode can be used in the synchronization mode to perform synchronization of touch sensing. The synchronization mode can be performed during the touch sensing operation.

[0131] It should also be noted that the above paragraphs describe various calibration operations and synchronization operations performed in a driving system having five driving circuits, but the present invention is not limited thereto. For example, in another embodiment, the calibration mode and synchronization mode operations may be performed in another driving system having a different number of driving circuits, such as 3, 4, 6, or 7. These driving circuits may be coupled together via two transmission buses to synchronize and jointly control a touch screen. In these driving circuits, the main control circuit may be disposed or set at any position.

[0132] In summary, the present invention proposes a driving system having a plurality of driving circuits, which are used to jointly control the touch sensing operation of a touch screen. One of the driving circuits can be set as a master circuit, and the other driving circuits are set as slave circuits. In the driving system, each driving circuit has two endpoints, one of which is commonly coupled to a transmission bus, and the other is commonly coupled to another transmission bus. Therefore, each driving circuit only includes two endpoints to complete the calibration and synchronization operations for touch sensing. In addition, the driving system can include any number of driving circuits without an upper limit, and the master circuit can be set at any position.

[0133] The driving circuit can be operated in a calibration mode and a synchronization mode. In the calibration mode, a synchronization signal can be transmitted through the transmission bus to obtain the path delay between any two driving circuits. In one embodiment, all driving circuits located on the right side or all driving circuits on the left side of a specific driving circuit can be calibrated by transmitting a forward synchronization signal and a backward synchronization signal. During the transmission of the synchronization signal, the input / output states of the two transmission buses should be consistent to achieve path symmetry.

[0134] In synchronous mode, the slave circuit may provide a notification to indicate that it is ready for touch sensing. The master circuit may monitor a transmission bus to receive the notification, or the notification may be transmitted via a command line. Upon receiving the notification, the master circuit may output an acknowledgment signal via a transmission bus, and then initiate a preset operation for touch sensing after a delay having a compensation time. The slave circuit may receive the acknowledgment signal via the transmission bus, and then initiate a preset operation for touch sensing after a delay having a respective compensation time. The compensation time corresponding to each driver circuit is calculated based on the path delay obtained in the calibration mode. Through appropriate delay control, each driver circuit may initiate the preset operation at the same time to perform touch sensing synchronously.

[0135] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A drive system, characterized in that: include: A plurality of driving circuits, each of which has a first terminal and a second terminal, the first terminal of each of the plurality of driving circuits is commonly coupled to a first transmission bus, the second terminal of each of the plurality of driving circuits is commonly coupled to a second transmission bus, and the plurality of driving circuits include: a first driving circuit, configured to output a first synchronization signal to the first transmission bus through the first endpoint; and a second driving circuit, configured to output a second synchronization signal to the second transmission bus through the second endpoint while receiving the first synchronization signal from the first transmission bus; A corresponding compensation time of the second driving circuit is calculated according to an output time point of the first synchronization signal and a receiving time point of the second synchronization signal.

2. The drive system according to claim 1, characterized in that: The plurality of driving circuits includes more than 3 driving circuits.

3. The drive system according to claim 1, characterized in that: A third driving circuit among the plurality of driving circuits receives the first synchronization signal from the first transmission bus through the first endpoint, and receives the second synchronization signal from the second transmission bus through the second endpoint.

4. The drive system according to claim 3, characterized in that: A compensation time corresponding to the third driving circuit is calculated according to a receiving time point of the first synchronization signal and a receiving time point of the second synchronization signal.

5. The drive system according to claim 1, characterized in that: The first driving circuit is a master driving circuit, which obtains a plurality of compensation times by outputting the first synchronization signal, wherein each compensation time corresponds to one of the plurality of driving circuits.

6. The drive system according to claim 1, characterized in that: The first driving circuit is a slave driving circuit, which sends the compensation time corresponding to the second driving circuit to a master driving circuit among the plurality of driving circuits.

7. The drive system according to claim 1, characterized in that: The first driving circuit is a master driving circuit, and the multiple driving circuits also include at least one first slave driving circuit located on a first side of the master driving circuit and at least one second slave driving circuit located on a second side of the master driving circuit, wherein the master driving circuit outputs the first synchronization signal to be received by the at least one first slave driving circuit, and outputs a third synchronization signal to be received by the at least one second slave driving circuit.

8. The drive system according to claim 1, characterized in that: When the first synchronization signal is transmitted, the first endpoint of the first driving circuit is set to an output state, and the first endpoints of the other driving circuits among the multiple driving circuits except the first driving circuit are set to an input state, and when the second synchronization signal is transmitted, the second endpoint of the second driving circuit is set to the output state, and the second endpoints of the other driving circuits among the multiple driving circuits except the second driving circuit are set to the input state.

9. The drive system according to claim 1, characterized in that: The plurality of driving circuits utilize the compensation time to synchronize a sensing time for touch sensing.

10. A drive system, characterized in that: include: A plurality of driving circuits, each of which has a first terminal and a second terminal, the first terminal of each of the plurality of driving circuits is commonly coupled to a first transmission bus, the second terminal of each of the plurality of driving circuits is commonly coupled to a second transmission bus, and the plurality of driving circuits include: at least one second driving circuit, wherein each driving circuit is used to generate a notification; and A first driving circuit, configured to: receiving the notification from each of the at least one second driving circuit; after receiving the notification from each of the at least one second driving circuit, outputting a confirmation signal through the first terminal; and After outputting the confirmation signal, starting a preset operation for sensing with a delay having a compensation time corresponding to the first driving circuit; The at least one second driving circuit also receives the confirmation signal through the first terminal, and after receiving the confirmation signal, starts the preset operation for sensing with a delay having a compensation time corresponding to each of the second driving circuits.

11. The drive system according to claim 10, characterized in that: The plurality of driving circuits includes more than 3 driving circuits.

12. The drive system according to claim 10, characterized in that: When each of the at least one second driving circuit obtains a sensing start signal, the second driving circuit generates the notification, and the first driving circuit outputs the confirmation signal after obtaining the sensing start signal.

13. The drive system according to claim 12, characterized in that: Each of the at least one second driving circuit generates the notification by converting the second terminal from a first level to a second level.

14. The drive system according to claim 13, characterized in that: The first driving circuit receives the notification by monitoring the second transmission bus to determine whether the second terminal of the first driving circuit is pulled to the second level.

15. The drive system according to claim 12, characterized in that: The first driving circuit receives the notification through a command line.

16. A first driving circuit coupled to at least one second driving circuit, characterized in that: Each of the first driving circuit and the at least one second driving circuit has a first terminal and a second terminal. The first terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a first transmission bus. The second terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a second transmission bus. The first driving circuit is used to: Outputting a first synchronization signal to the first transmission bus via the first endpoint; receiving a second synchronization signal from the second transmission bus through the second endpoint, wherein the second synchronization signal is output by the second driving circuit among the at least one second driving circuits at the same time when the second driving circuit among the at least one second driving circuits receives the first synchronization signal; as well as A compensation time corresponding to the second driving circuit in the at least one second driving circuit is calculated according to an output time point of the first synchronization signal and a receiving time point of the second synchronization signal.

17. The first driving circuit according to claim 16, wherein: The at least one second driving circuit includes more than two second driving circuits.

18. The first driving circuit according to claim 16, wherein: The first synchronization signal is received by another second driving circuit among the at least one second driving circuit from the first transmission bus through the first endpoint, and the second synchronization signal is received by another second driving circuit among the at least one second driving circuit from the second transmission bus through the second endpoint.

19. The first driving circuit according to claim 18, characterized in that: A compensation time corresponding to another second driving circuit in the at least one second driving circuit is calculated according to a receiving time point of the first synchronization signal and a receiving time point of the second synchronization signal.

20. The first driving circuit according to claim 16, wherein: The first driving circuit is a master driving circuit, which obtains a plurality of compensation times by outputting the first synchronization signal, wherein each compensation time corresponds to one of the at least one second driving circuit.

21. The first driving circuit according to claim 16, wherein: The first driving circuit is a slave driving circuit, which sends the compensation time corresponding to the second driving circuit in the at least one second driving circuit to a master driving circuit in the at least one second driving circuit.

22. The first driving circuit according to claim 16, wherein: The first driving circuit is a master driving circuit, and the at least one second driving circuit includes at least one first slave driving circuit located on a first side of the master driving circuit and at least one second slave driving circuit located on a second side of the master driving circuit, wherein the master driving circuit outputs the first synchronization signal to be received by the at least one first slave driving circuit, and outputs a third synchronization signal to be received by the at least one second slave driving circuit.

23. The first driving circuit according to claim 16, characterized in that: When the first synchronization signal is transmitted, the first endpoint of the first driving circuit is set to an output state, and the first endpoint of the at least one second driving circuit is set to an input state, and when the second synchronization signal is transmitted, the second endpoint of the second driving circuit that outputs the second synchronization signal in the at least one second driving circuit is set to the output state, and the second endpoints of the other second driving circuits in the first driving circuit and the at least one second driving circuit except the second driving circuit set to the output state are set to the input state.

24. The first driving circuit according to claim 16, wherein: The first driving circuit utilizes the compensation time to synchronize with the at least one second driving circuit for a sensing time for touch sensing.

25. A first driving circuit coupled to at least one second driving circuit, characterized in that: Each of the first driving circuit and the at least one second driving circuit has a first terminal and a second terminal. The first terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a first transmission bus. The second terminal of each of the first driving circuit and the at least one second driving circuit is commonly coupled to a second transmission bus. The first driving circuit is used to: receiving a notification from each of the at least one second driver circuit; After receiving the notification from each of the at least one second driving circuit, Outputting a confirmation signal through the first endpoint; as well as After the confirmation signal is output, a preset operation for sensing is initiated with a delay having a compensation time corresponding to the first driving circuit.

26. The first driving circuit according to claim 25, characterized in that: The at least one second driving circuit includes more than two driving circuits.

27. The first driving circuit according to claim 25, characterized in that: The first driving circuit outputs the confirmation signal after obtaining a sensing start signal.

28. The first driving circuit according to claim 27, characterized in that: The first driving circuit receives the notification by monitoring the second transmission bus to determine whether the second terminal of the first driving circuit is pulled from a first level to a second level.

29. The first driving circuit according to claim 25, characterized in that: The first driving circuit receives the notification through a command line.

30. A second driving circuit coupled to a first driving circuit, characterized in that: Each of the first driving circuit and the second driving circuit has a first terminal and a second terminal. The first terminal of each of the first driving circuit and the second driving circuit is commonly coupled to a first transmission bus. The second terminal of each of the first driving circuit and the second driving circuit is commonly coupled to a second transmission bus. The second driving circuit is used to: generate a notification; receiving a confirmation signal from the first driving circuit via the first terminal, wherein the confirmation signal is generated in response to the notification; as well as After receiving the confirmation signal, a preset operation for sensing is initiated with a delay having a compensation time corresponding to the second driving circuit.

31. The second driving circuit according to claim 30, characterized in that: The second driving circuit is coupled to more than two driving circuits.

32. The second driving circuit according to claim 30, characterized in that: The second driving circuit generates the notification when obtaining a sensing start signal.

33. The second driving circuit according to claim 32, characterized in that: The second driving circuit generates the notification by converting the second terminal from a first level to a second level.

34. The second driving circuit according to claim 30, characterized in that: The second driving circuit outputs the notification through a command line.

Images