Display driving system and method for display driving system

Abstract

The present disclosure provides a method for a display driving system and a display driving system. The method includes: a control circuit sends a global signal and a first signal for each stage of the LED driving circuit to a first-stage LED driving circuit, the global signal including an instruction for indicating an operating mode of each stage of the LED driving circuit; each stage of the LED driving circuit determines an operating mode corresponding to the instruction based on the global signal, identifies the first signal corresponding to the LED driving circuit of the stage, and operates according to the determined operating mode and the corresponding first signal; each stage of the LED driving circuit except the last stage sends a global signal to the LED driving circuit of the next stage, and in response to completing the operation according to the determined operating mode and the corresponding first signal, sends the first signal for the subsequent stages of the LED driving circuit to the LED driving circuit of the next stage.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to U.S. Provisional Application No. 62 / 937,802, filed on November 20, 2019, entitled “Protocol for differential cascade driver system,” which is incorporated by reference in its entirety into this disclosure. Technical Field

[0003] The present disclosure relates to an electronic device, and more particularly to a method for a display driving system and a corresponding display driving system. Background Art

[0004] The Serial Peripheral Interface (SPI) has been applied to serially connected LED driver systems to provide a communication interface between the control circuit and multiple LED driver circuits within the LED driver system. In this structure, when the control circuit writes data to or reads data from the LED driver circuit, it uses an additional pin or chip select signal to determine the LED driver circuit to which the data corresponds.

[0005] However, SPI has numerous drawbacks. Specifically, its transmission voltage swing is large—for example, the input high level (VIH) is 4.6V and the input low level (VIL) is 0V, resulting in slow data transmission. Furthermore, its multi-drop frequency connection is highly susceptible to environmental noise, consumes high power, and has poor electrostatic discharge (ESD) tolerance.

[0006] Therefore, a novel display driving system and a corresponding driving method are needed. Summary of the Invention

[0007] To this end, the present disclosure proposes a method for a display driving system and a corresponding display driving system.

[0008] According to one aspect of the present disclosure, a method for a display driving system is provided, wherein the display driving system includes a control circuit and a multi-stage light-emitting diode driving circuit connected in cascade, the method including: the control circuit sending a global signal and a first signal for each stage of the light-emitting diode driving circuit to a first stage of the multi-stage light-emitting diode driving circuit, wherein the global signal includes an instruction for indicating an operating mode of each stage of the light-emitting diode driving circuit; each stage of the light-emitting diode driving circuit determines an operating mode corresponding to the instruction based on the global signal, identifies the first signal corresponding to the light-emitting diode driving circuit of the stage, and operates according to the determined operating mode and the corresponding first signal; and each stage of the light-emitting diode driving circuit except the last stage of the light-emitting diode driving circuit sends a global signal to the light-emitting diode driving circuit of the next stage thereof, and in response to completion of the operation according to the determined operating mode and the corresponding first signal, sends the first signal for each stage of the light-emitting diode driving circuit subsequent to the light-emitting diode driving circuit of the stage thereof to the light-emitting diode driving circuit of the next stage thereof.

[0009] According to another aspect of the present disclosure, a display driving system is provided, comprising: a control circuit and a multi-stage LED driving circuit connected in cascade, wherein the control circuit is configured to send a global signal and a first signal for each stage of the LED driving circuit to a first stage of the LED driving circuit in the multi-stage LED driving circuit, wherein the global signal includes an instruction for indicating an operating mode of each stage of the LED driving circuit; each stage of the LED driving circuit is configured to determine an operating mode corresponding to the instruction based on the global signal, identify the first signal corresponding to the LED driving circuit of this stage, and operate according to the determined operating mode and the corresponding first signal; and each stage of the LED driving circuit except the last stage of the LED driving circuit is further configured to send the global signal to the LED driving circuit of the next stage thereof, and in response to completion of the operation according to the determined operating mode and the corresponding first signal, send the first signal for each stage of the LED driving circuit following the LED driving circuit of this stage to the LED driving circuit of the next stage thereof.

[0010] In order to make the above features and advantages of the present disclosure more obvious and easy to understand, embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0012] Figure 1A schematic diagram of a display driving system according to an embodiment of the present disclosure is shown.

[0013] Figure 2A 4 is a flowchart of a method for performing writing and / or reading operations in a display driving system according to an embodiment of the present disclosure.

[0014] Figure 2B It is a specific flow chart of a method for performing a write operation in a display driving system according to an embodiment of the present disclosure.

[0015] Figure 2C It is a specific flow chart of a method for performing a reading operation by a display driving system according to an embodiment of the present disclosure.

[0016] Figure 3 A schematic diagram showing the process of a display driving system performing a write operation is shown.

[0017] Figure 4 Another schematic diagram of the process of the display driving system performing a writing operation is shown.

[0018] Figure 5 A schematic diagram of the process of a display driving system performing a reading operation is shown.

[0019] Figure 6 FIG. 4 shows a state diagram of a light emitting diode driving circuit in a writing mode / reading mode according to an embodiment of the present disclosure.

[0020] Figure 7 is a flowchart of a method for a display driving system to enter a power saving mode according to a first example of an embodiment of the present disclosure.

[0021] Figure 8 A schematic diagram showing the process of the display driving system entering the power saving mode is shown.

[0022] Figure 9 is a flowchart of a method for a display driving system to enter a power saving mode according to a second example of an embodiment of the present disclosure.

[0023] Figure 10 The present invention is a flowchart of a method for performing power-on protection operation in a display driving system according to an embodiment of the present disclosure.

[0024] Figure 11 A schematic diagram showing the process of the display driver system entering the power-on protection mode is shown.

[0025] Figure 12 Another schematic diagram of the process of the display driving system entering the power-on protection mode is shown. DETAILED DESCRIPTION

[0026] The term "coupled (or connected)" as used throughout this disclosure (including the claims) may refer to any direct or indirect means of connection. For example, if the text describes a first device coupled (or connected) to a second device, it should be interpreted as the first device being directly connected to the second device, or the first device being indirectly connected to the second device through other devices or some means of connection. The terms "first", "second", etc. mentioned throughout this disclosure (including the claims) are used to name elements or to distinguish different embodiments or ranges, and are not used to limit the upper or lower limit of the number of elements, nor to limit the order of elements. In addition, wherever possible, elements / components / steps using the same figure numbers in the drawings and embodiments represent the same or similar parts. Elements / components / steps using the same figure numbers or the same terms in different embodiments can refer to the relevant descriptions of each other.

[0027] In the present disclosure, a display drive system may include a control circuit and a multi-stage light-emitting diode (LED) driver circuit connected in cascade. Specifically, the output end of the control circuit may be connected to the input end of the first-stage LED driver circuit in the multi-stage LED driver circuit. The output end of each stage of the LED driver circuit, except for the last stage of the LED driver circuit, may be connected to the input end of the next-stage LED driver circuit. The output end of the last stage of the LED driver circuit may be connected to the input end of the control circuit. In addition, the control circuit may be configured with two output ends, and each stage of the LED driver circuit may be configured with two input ends and two output ends, respectively for transmitting a clock signal and a data signal.

[0028] It should be understood that the control circuit can be configured with more than two output terminals, and each diode driving circuit can be configured with more than two input terminals and more than two output terminals to transmit other signals (such as the synchronization signal described below).

[0029] Figure 1 FIG. 1 shows a schematic diagram of a display driving system according to an embodiment of the present disclosure. Figure 1As shown, the display driver system 100 may include a control circuit 110 and three-stage LED driver circuits, namely a first-stage LED driver circuit 120-1, a second-stage LED driver circuit 120-2, and a third-stage LED driver circuit 120-3. The first output terminal of the control circuit 110 may be connected to the first input terminal of the first-stage LED driver circuit 120-1, the first output terminal of the first-stage LED driver circuit 120-1 may be connected to the first input terminal of the second-stage LED driver circuit 120-2, and the first output terminal of the second-stage LED driver circuit 120-2 may be connected to the first input terminal of the third-stage LED driver circuit 120-5. This path may be used for the control circuit to transmit a clock signal to the LED driver circuit. In addition, the second output terminal of the control circuit 110 can be connected to the second input terminal of the first-stage LED driver circuit 120-1, the second output terminal of the first-stage LED driver circuit 120-1 can be connected to the second input terminal of the second-stage LED driver circuit 120-2, the second output terminal of the second-stage LED driver circuit 120-2 can be connected to the second input terminal of the third-stage LED driver circuit 120-3, and the second output terminal of the third-stage LED driver circuit 120-3 can be connected to the input terminal of the control circuit 110. This path can be a path for the control circuit to transmit data signals to the LED driver circuit.

[0030] For the display driver system disclosed herein, a signal transmission protocol can be designed so that the control circuit and the LED driver circuits at each level in the display driver system can communicate according to the signal transmission protocol. The operating modes of the LED driver circuit can include one or more of a write mode, a read mode, a power-saving mode, and a power-on protection mode. The signal transmission protocol can be designed for these operating modes.

[0031] Specifically, for the write mode and / or read mode, the signal transmission protocol may stipulate that: the control circuit sends a global signal and a first signal for each level of the LED driving circuit to the first level of the multi-level LED driving circuit in sequence, wherein the global signal includes an instruction for indicating the operating mode (write mode or read mode) of each level of the LED driving circuit; when the first level of the LED driving circuit recognizes the global signal, it determines the corresponding operating mode according to the global signal and sends the global signal to its next level of the LED driving circuit, so that the next level of the LED driving circuit also determines the corresponding operating mode according to the global signal when recognizing the global signal and sends the global signal to its own next level of the LED driving circuit, until the last level of the LED driving circuit obtains the global signal and determines the corresponding operating mode. operation mode; after receiving the global signal, the first-stage LED driver circuit identifies the first signal sent by the control circuit for the LED driver circuit of this stage, and operates according to the determined operation mode and the corresponding first signal, and enters the bypass state after the operation is completed (that is, the received signal is not processed but sent to the next-stage LED driver circuit; that is, after the operation is completed, the first signal received from the control circuit for the remaining LED driver circuits is not processed but sent to the next-stage LED driver circuit). Each stage of the LED driver circuit except the last stage performs similar actions as the first stage of the LED driver circuit until the last stage of the LED driver circuit operates according to the determined operation mode and the corresponding first signal.

[0032] In addition, for the power saving mode, the signal transmission protocol may stipulate that: the control circuit sends another global signal to the first-level LED driving circuit in the multi-level LED driving circuit, wherein the another global signal includes instructions for indicating another operating mode (power saving mode) of each level of LED driving circuit; when the first-level LED driving circuit recognizes the another global signal, it determines the corresponding operating mode according to the another global signal, and sends the another global signal to its next-level LED driving circuit, so that the next-level LED driving circuit also determines the corresponding operating mode according to the another global signal when recognizing the another global signal and sends the another global signal to its own next-level LED driving circuit, until the last-level LED driving circuit obtains the another global signal and determines the corresponding operating mode. Alternatively, for the power saving mode, the signal transmission protocol may further stipulate that: the first-level LED driving circuit determines whether the length of the time period in which it receives specific data from its control circuit is greater than a preset threshold value, and if so, changes the current operating mode to the power saving mode; each level of LED driving circuit except the first-level LED driving circuit determines whether the length of the time period in which it receives specific data from its upper-level LED driving circuit is greater than a preset threshold value, and if so, changes the current operating mode to the power saving mode.

[0033] In addition, for the power-on protection mode, the signal transmission protocol may stipulate that: the control circuit changes the level of the synchronization signal sent to each level of the light-emitting diode driving circuit according to a preset period; after the control circuit is turned on and before sending a global signal and a first signal for each level of the light-emitting diode driving circuit to the first level of the multi-level light-emitting diode driving circuit, the control circuit sends a first preset data to the first level of the light-emitting diode driving circuit; for each level of the light-emitting diode driving circuit in the multi-level light-emitting diode driving circuit, the following operations are performed: if the first preset data is not received or if the first preset data is received but the level of the synchronization signal does not change for a preset number of times, the second preset data is sent to its downstream circuit; after receiving the When the first preset data is received and the level of the synchronization signal changes a preset number of times, the first preset data is sent to its downstream circuit; wherein, for the last-level LED driving circuit in the multi-level LED driving circuit, its downstream circuit is the control circuit, and for each level of LED driving circuit except the last-level LED driving circuit in the multi-level LED driving circuit, its downstream circuit is its next-level LED driving circuit; in response to the control circuit receiving the first preset data from the last-level LED driving circuit, the control circuit starts to send the global signal and the first signal for each level of LED driving circuit to the first-level LED driving circuit in the multi-level LED driving circuit.

[0034] Through the above-mentioned signal transmission protocol, each LED driving circuit in the display driving system can identify the data to be sent to itself by the control circuit, thereby eliminating the need for additional pins or chip select signals to determine the corresponding LED driving circuit, avoiding the use of SPI and thus avoiding certain defects caused by SPI.

[0035] In addition, in the present disclosure, the “control circuit” may be, but is not limited to, a timing controller. In addition, the “light emitting diode driving circuit” in the present disclosure may be an integrated circuit (IC).

[0036] The following will be combined Figure 2A The specific process of writing and / or reading operations performed by the display driving system according to the above signal transmission protocol is described below. Figure 2A 4 is a flowchart of a method for performing writing and / or reading operations in a display driving system according to an embodiment of the present disclosure.

[0037] like Figure 2A As shown, method 200 includes three steps, namely step S201, step S202, and step S203. Specifically, in step S201, the control circuit sends a global signal and a first signal for each stage of the LED driver circuit to the first stage of the multi-stage LED driver circuit, wherein the global signal includes an instruction for indicating the operating mode of each stage of the LED driver circuit. In step S202, each stage of the LED driver circuit determines the operating mode corresponding to the instruction based on the global signal, identifies the first signal corresponding to the LED driver circuit of the stage, and operates according to the determined operating mode and the corresponding first signal. In step S203, each stage of the LED driver circuit, except for the last stage of the LED driver circuit, sends the global signal to the LED driver circuit of the next stage, and in response to completing the operation according to the determined operating mode and the corresponding first signal, sends the first signal for each stage of the LED driver circuit after the stage of the LED driver circuit to the next stage of the LED driver circuit.

[0038] It should be noted that the execution order of steps S202 and S203 is not to execute step S202 first and then execute step S203, but rather to execute some sub-steps of steps S202 and S203 first, and then execute other sub-steps of steps S202 and S203. Specifically, after the control circuit described in step S201 sends a global signal to the first-stage LED driver circuit in the multi-stage LED driver circuit, the sub-steps of step S202 (each stage of the LED driver circuit determines the operating mode corresponding to the instruction based on the global signal) and the sub-steps of step S203 (each stage of the LED driver circuit, except the last stage of the LED driver circuit, sends the global signal to the next stage of the LED driver circuit) can be executed. After the control circuit described in step S201 sends the first signal for each stage of the LED driving circuit to the first stage of the LED driving circuit in the multi-stage LED driving circuit, another sub-step in step S202 can be executed (each stage of the LED driving circuit identifies the first signal corresponding to the LED driving circuit of that stage, and operates according to the determined operation mode and the corresponding first signal), and another sub-step in step S203 (each stage of the LED driving circuit except the last stage of the LED driving circuit, in response to completing the operation according to the determined operation mode and the corresponding first signal, sends the first signal for each stage of the LED driving circuit after the LED driving circuit of that stage to the LED driving circuit of the next stage).

[0039] The following describes a specific implementation of the method 200 by taking a display driver system performing a write operation as an example. Figure 2B 2 is a specific flow chart of a method 200' for performing a write operation on a display driving system according to an embodiment of the present disclosure. The method 200' includes Figure 2A Steps S201 to S203 are shown.

[0040] In step S201, the instruction in the global signal may be referred to as a global instruction or global command (GlobalCommand). According to one example of the present disclosure, the instruction in the global signal may be a write command (Write Command, abbreviated as WR CMD), and the operation mode corresponding to the instruction is the write mode. Accordingly, each stage of the light-emitting diode driving circuit may determine that the operation mode corresponding to the instruction is the write mode based on the global signal.

[0041] In addition, the global signal in step S201 may further include data related to clock training (ClockTraining, CT) and a command transmission indication (Command Start, CS). In this case, the data related to clock training (CT), the command transmission indication (CS), and the instruction may be transmitted in sequence. In addition, in the example where the instruction in the global signal is a write instruction (WR CMD), the global signal may include data related to clock training (CT), the command transmission indication (CS), and the write instruction (WR CMD), and the data related to clock training (CT), the command transmission indication (CS), and the write instruction (WR CMD) may be transmitted in sequence.

[0042] While the upstream circuit is transmitting CT, part of the global signal, to the LED driver circuit, the LED driver circuit can be in a waiting state for CT and in a bypass state. As described above, the LED driver circuit being in the bypass state means that the LED driver circuit does not process the received signal and instead sends it to its downstream circuit. Furthermore, while the upstream circuit is transmitting CS and WR CMD, part of the global signal, to the LED driver circuit, the LED driver circuit can write WR CMD and be in a bypass state. The final-stage LED driver circuit can feed back the received global signal to the control circuit.

[0043] For the first-stage LED driving circuit in a multi-stage LED driving circuit, its upstream circuit is the control circuit, and its downstream circuit is the LED driving circuit of the next stage; for each stage LED driving circuit except the first-stage LED driving circuit and the last-stage LED driving circuit in the multi-stage LED driving circuit, its upstream circuit is the LED driving circuit of the previous stage, and its downstream circuit is the LED driving circuit of the next stage; for the last-stage LED driving circuit in the multi-stage LED driving circuit, its upstream circuit is the LED driving circuit of the previous stage, and its downstream circuit is the control circuit.

[0044] In other words, while the control circuit transmits CT from the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and WR CMD from the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write WR CMD and be in a bypass state. Furthermore, while the upper-stage LED driver circuit transmits CT from the global signal to the lower-stage LED driver circuit, the lower-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the upper-stage LED driver circuit transmits CS and WR CMD from the global signal to the lower-stage LED driver circuit, the lower-stage LED driver circuit can write WR CMD and be in a bypass state. In other words, the LED driver circuits of each stage other than the first-stage LED driver circuit receive CT, CS, and WR CMD from the upper-stage LED driver circuit through the upper-stage LED driver circuit's bypass state.

[0045] Furthermore, in the example where the instruction in the global signal is a write instruction, the first signal for each stage of the LED driver circuit in step S201 may include at least the data (DATA) to be written for that stage of the LED driver circuit. Furthermore, the first signal for each stage of the LED driver circuit may also include data (CT) related to clock training and / or a data transmission instruction (Data Start, DS). In this case, the data (CT) related to clock training, the data transmission instruction (DS), and the data (DATA) to be written may be transmitted sequentially.

[0046] In addition, according to an example of the present disclosure, in step S202, for each stage of the multi-stage LED driver circuit, operating according to the determined operation mode and the corresponding first signal may include: two sub-steps, namely step S2021' and step S2022'. Specifically, in step S2021', if the data to be written for the LED driver circuit of the stage is not received, preset data is sent to its downstream circuit; in step S2022', if the data to be written for the LED driver circuit of the stage is received, the data to be written for the LED driver circuit of the stage is written and the preset data is sent to the downstream circuit; wherein, for the last stage of the LED driver circuit in the multi-stage LED driver circuit, its downstream circuit is the control circuit; and for each stage of the LED driver circuit in the multi-stage LED driver circuit except the last stage, its downstream circuit is the LED driver circuit of the next stage.

[0047] Furthermore, in step S203, each stage of the LED driver circuit except the last stage, in response to completing the operation according to the determined operation mode and the corresponding first signal, sends a first signal for each subsequent stage of the LED driver circuit to the next stage of the LED driver circuit. For example, each stage of the LED driver circuit except the last stage, in response to completing the operation according to the determined operation mode and the corresponding first signal, may enter a state of waiting for the control circuit to indicate the end of the determined operation mode (e.g., waiting for the control circuit to change the level of the synchronization signal) and enter a bypass state. While in the bypass state, the first signals received for the subsequent stages of the LED driver circuit may not be processed, but instead the first signals for the subsequent stages of the LED driver circuit may be sent to the next stage of the LED driver circuit.

[0048] Specifically, while the upstream circuit is transmitting CT in the first signal for the LED driver circuit of the current stage, the LED driver circuit may be in a waiting state for DS. Since the data to be written (DATA) for the LED driver circuit of the current stage has not been received, the LED driver circuit outputs preset data to its downstream circuit. While the upstream circuit is transmitting DS and the data to be written (DATA) in the first signal for the LED driver circuit of the current stage, the LED driver circuit may write the data to be written and continue to output preset data to its downstream circuit. After writing the data to be written, the LED driver circuit of the current stage enters a bypass state, i.e., it transmits the first signal received from the upstream circuit for the LED driver circuits of the subsequent stages to the LED driver circuit of the current stage to the LED driver circuit of the next stage. The upstream and downstream circuits of the LED driver circuit have been explained above and will not be repeated here.

[0049] In other words, during the period when the control circuit transmits CT in the first signal for the first-level LED driver circuit to the first-level LED driver circuit, the first-level LED driver circuit can be in a state of waiting for DS, and because the data to be written (DATA) for the first-level LED driver circuit is not received, the preset data is output to the next-level LED driver circuit; during the period when the control circuit transmits DS and the data to be written (DATA) in the first signal for the first-level LED driver circuit to the first-level LED driver circuit, the first-level LED driver circuit can write the data to be written and continue to output the preset data to the next-level LED driver circuit.

[0050] In addition, for each level of LED driving circuit except the first level LED driving circuit and the last level LED driving circuit in the multi-level LED driving circuit, during the period when the previous level LED driving circuit transmits preset data and CT in the first signal for the LED driving circuit of this level to the LED driving circuit of this level, the LED driving circuit of this level can be in a state of waiting for DS, and because the data to be written (DATA) for the LED driving circuit of this level is not received, the preset data is output to the LED driving circuit of the next level; during the period when the previous level LED driving circuit transmits DS and data to be written (DATA) in the first signal for the LED driving circuit of this level to the LED driving circuit of this level, the LED driving circuit of this level can write the data to be written and continue to output the preset data to the LED driving circuit of the next level.

[0051] In addition, for the last-level LED driving circuit in the multi-level LED driving circuit, during the period when the previous-level LED driving circuit transmits the preset data and CT in the first signal for the LED driving circuit of this level to the LED driving circuit of this level, the LED driving circuit of this level can be in a state of waiting for DS, and because the data to be written (DATA) for the LED driving circuit of this level is not received, the preset data is output to the control circuit; during the period when the previous-level LED driving circuit transmits DS and the data to be written (DATA) in the first signal for the LED driving circuit of this level to the LED driving circuit of this level, the LED driving circuit of this level can write the data to be written and continue to output the preset data to the control circuit.

[0052] In addition, after the control circuit sends the global signal and the first signal for each stage of the LED driving circuit to the first stage of the multi-stage LED driving circuit, Figure 2B The illustrated method 200' may further include step S204'. In step S204', the control circuit transmits specific data to the first-stage LED driver circuit in the multi-stage LED driver circuit. As described above, after writing the data to be written, each stage of the LED driver circuit is in a bypass state. Therefore, each stage of the LED driver circuit can transmit the specific data to its downstream circuit. Specifically, each stage of the LED driver circuit, except for the last stage, can transmit the specific data to the next-stage LED driver circuit; the last stage of the LED driver circuit can feed the specific data back to the control circuit.

[0053] In addition, after step S204', Figure 2BThe illustrated method 200' may further include step SS205'. In step S205', the control circuit instructs the LED driver circuits of each stage to terminate the determined operating mode. For example, the control circuit may change the level of the synchronization signal it sends to the LED driver circuits of each stage (e.g., from a high level to a low level, or from a low level to a high level). Accordingly, the LED driver circuits of each stage may terminate the current operating mode upon detecting the change in the level of the synchronization signal.

[0054] In addition, the preset data mentioned above can be data with a preset value. The preset value can be, for example, 0 or 1. The specific data mentioned above can be, for example, data related to clock training (CT). CT can be used as dummy data and can be defined as values ​​​​not equal to DS and CS. In addition, CT and / or DS can be used as the header of a data packet, and the data to be written (DATA) can be used as the data part of the data packet. In addition, the data to be written (DATA) can be display data (e.g., grayscale data) or a set value.

[0055] The following example shows that the display drive system includes a control circuit and a three-stage light-emitting diode drive circuit and performs a write operation. Figure 3 and Figure 4 , the specific process of method 200' is described again.

[0056] Figure 3 FIG. 1 shows a schematic diagram of a process in which a display driver system performs a write operation. Figure 3 As shown, the control circuit sequentially sends a global signal, a first signal for each level of LED driver circuit, and specific data to the first-level LED. The global signal includes data related to clock training (CT), a command transmission indication (CS), and a write instruction (WRCMD). The first signal for the first-level LED driver circuit includes data related to clock training (CT), a data transmission instruction (DS), and the data to be written (DATA1) to be written by the first-level LED driver circuit. The first signal for the second-level LED driver circuit includes data related to clock training (CT), a data transmission instruction (DS), and the data to be written (DATA2) to be written by the second-level LED driver circuit. The first signal for the third-level LED driver circuit includes data related to clock training (CT), a data transmission instruction (DS), and the data to be written (DATA3) to be written by the third-level LED driver circuit. The specific data is data related to clock training (CT).

[0057] In addition, if Figure 3As shown, while the control circuit transmits CT in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and WR CMD in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write WR CMD and be in a bypass state. Furthermore, while the first-stage LED driver circuit transmits CT in the global signal to the second-stage LED driver circuit, the second-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the first-stage LED driver circuit transmits CS and WR CMD in the global signal to the second-stage LED driver circuit, the second-stage LED driver circuit can write WR CMD and be in a bypass state. Furthermore, while the second-stage LED driver circuit transmits CT in the global signal to the third-stage LED driver circuit, the third-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the second-stage LED driver circuit transmits CS and WR CMD in the global signal to the third-stage LED driver circuit, the third-stage LED driver circuit can write WR CMD and be in a bypass state. The third-stage light-emitting diode driving circuit can feed back the received global signal to the control circuit.

[0058] Furthermore, while the control circuit transmits CT in the first signal for the first-stage LED driver circuit to the first-stage LED driver circuit, the first-stage LED driver circuit may be in a waiting state for DS and, having not received the data (DATA1) to be written to the first-stage LED driver circuit, outputs 0 to the second-stage LED driver circuit. While the control circuit transmits DS and the data (DATA1) to be written in the first signal for the first-stage LED driver circuit to the first-stage LED driver circuit, the first-stage LED driver circuit may write the data (DATA1) to be written and continue to output 0 to the second-stage LED driver circuit. Thereafter, the first-stage LED driver circuit waits for the control circuit to change the level of the synchronization signal and enters a bypass state. Therefore, the first-stage LED driver circuit transmits the first signal for the second-stage LED driver circuit and the first signal for the third-stage LED driver circuit received from the control circuit to the second-stage LED driver circuit.

[0059] While the first-stage LED driver circuit transmits 0 and the CT in the first signal for the second-stage LED driver circuit to the second-stage LED driver circuit, the second-stage LED driver circuit can be in a waiting state for DS. Since it has not received the data (DATA2) to be written to the second-stage LED driver circuit, it outputs 0 to the third-stage LED driver circuit. While the first-stage LED driver circuit transmits DS and the data (DATA2) to be written in the first signal for the second-stage LED driver circuit to the second-stage LED driver circuit, the second-stage LED driver circuit can write the data (DATA2) to be written and continue to output 0 to the third-stage LED driver circuit. Thereafter, the second-stage LED driver circuit waits for the control circuit to change the level of the synchronization signal and enters a bypass state. Therefore, the second-stage LED driver circuit transmits the first signal for the third-stage LED driver circuit received from the first-stage LED driver circuit to the third-stage LED driver circuit.

[0060] During the period when the second-level LED driving circuit transmits 0 and CT in the first signal for the third-level LED driving circuit to the third-level LED driving circuit, the third-level LED driving circuit can be in a state of waiting for DS, and because the data to be written (DATA3) for the third-level LED driving circuit is not received, it outputs 0 to the control circuit; during the period when the second-level LED driving circuit transmits DS and the data to be written (DATA3) in the first signal for the third-level LED driving circuit to the third-level LED driving circuit, the third-level LED driving circuit can write the data to be written (DATA3) and continue to output 0 to the control circuit.

[0061] After writing the data to be written, each stage of the LED driver circuit is in a bypass state. Therefore, the first stage LED driver circuit can send the CT received from the control circuit to the second stage LED driver circuit, the second stage LED driver circuit can send the CT received from the first stage LED driver circuit to the third stage LED driver circuit, and the third stage LED driver circuit can feed back the CT received from the second stage LED driver circuit to the control circuit.

[0062] Afterwards, the control circuit may change the level of the synchronization signal (not shown in the figure) sent to each level of the LED driving circuit to instruct the LED driving circuits at each level to end the writing mode.

[0063] In this way, the data to be written can be written into each level of LED driving circuit in sequence until the level of the synchronization signal changes. In this way, there is no need to spend additional pins or chip select signals or other judgment mechanisms to determine the LED driving circuit corresponding to the data.

[0064] It should be understood that the above example is based on an ideally aligned timing, i.e., there is no delay in the signal transmission process. When there is a delay in the signal transmission process, the signal may be delayed step by step between the control circuit and each level of the LED driver circuit. Figure 4 FIG. 2 shows another process diagram of a display driver system performing a write operation. Figure 4 As shown, the time when the third-stage LED driver circuit receives the global signal from the second-stage LED driver circuit is later than the time when the second-stage LED driver circuit receives the global signal from the first-stage LED driver circuit, and the time when the second-stage LED driver circuit receives the global signal from the first-stage LED driver circuit is later than the time when the first-stage LED driver circuit receives the global signal from the control circuit. However, this delay does not affect the operation of the control circuit and the LED driver circuits of each stage described above.

[0065] Next, a specific implementation of the method 200 is described by taking a display driving system performing a reading operation as an example. Figure 2C is a specific flow chart of a method 200" for performing a reading operation on a display driving system according to an embodiment of the present disclosure. The method 200" includes Figure 2A Steps S201 to S203 are shown.

[0066] In step S201, the instruction in the global signal may be a read instruction (Read Command, RD CMD), and the operation mode corresponding to the instruction is the read mode. Accordingly, each stage of the LED driving circuit may determine that the operation mode corresponding to the instruction is the read mode based on the global signal.

[0067] In addition, the global signal in step S201 may further include data related to clock training (ClockTraining, CT) and a command transmission indication (Command Start, CS). In this case, the data related to clock training (CT), the command transmission indication (CS), and the instruction may be transmitted in sequence. In addition, in the example where the instruction in the global signal is a read instruction (RD CMD), the global signal may include data related to clock training (CT), the command transmission indication (CS), and the read instruction (RD CMD), and the data related to clock training (CT), the command transmission indication (CS), and the read instruction (RD CMD) may be transmitted in sequence.

[0068] While the upstream circuit transmits CT, a global signal, to the LED driver circuit, the LED driver circuit can be in a waiting state for CT and in a bypass state. Furthermore, while the upstream circuit transmits CS and RD CMD, global signals, to the LED driver circuit, the LED driver circuit can write RD CMD and be in a bypass state. The final-stage LED driver circuit can feed back the received global signal to the control circuit. The upstream and downstream circuits of the LED driver circuit have been explained above and will not be repeated here.

[0069] In other words, while the control circuit is transmitting CT from the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit is transmitting CS and RD CMD from the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write RD CMD and be in a bypass state. Furthermore, while the previous-stage LED driver circuit is transmitting CT from the global signal to the next-stage LED driver circuit, the next-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the previous-stage LED driver circuit is transmitting CS and RD CMD from the global signal to the next-stage LED driver circuit, the next-stage LED driver circuit can write RD CMD and be in a bypass state. The final-stage LED driver circuit can feed back the received global signal to the control circuit.

[0070] In addition, in the example where the instruction in the global signal is a read instruction, the first signal for each level of light-emitting diode driver circuit in step S201 includes first data and second data for the light-emitting diode driver circuit of that level. The first data includes an enable instruction, such as an output enable (OE) instruction. The first data may also include data (CT) related to clock training. In this case, the data (CT) related to clock training and the output enable (OE) instruction may be transmitted sequentially, or a portion of the CT, the output enable (OE) instruction, and another portion of the CT may be transmitted sequentially. In addition, the second data may include data (CT) related to clock training.

[0071] In this example, the control circuit sending a first signal for each level of light-emitting diode driving circuit to the first-level light-emitting diode driving circuit in the multi-level light-emitting diode driving circuit may include: the control circuit sending a first signal for the i-th level light-emitting diode driving circuit in a preset time period corresponding to the i-th level light-emitting diode driving circuit, wherein the preset time period includes a first time period (for example, T1) and a second time period (for example, T2), the control circuit sends first data for the i-th level light-emitting diode driving circuit in the first time period and sends second data for the i-th level light-emitting diode driving circuit in the second time period, wherein the multi-level light-emitting diode driving circuit is an N-level light-emitting diode driving circuit, N is an integer greater than or equal to 3, and i is an integer greater than or equal to 1 and less than or equal to N.

[0072] According to an example of the present disclosure, the first time period and the second time period for a certain LED driving circuit may have the same duration or different durations. Furthermore, the first time period for different LED driving circuits may have the same duration or different durations. Furthermore, the second time period for different LED driving circuits may have the same duration or different durations.

[0073] Taking the example of a first time period and a second time period for each LED driver circuit having the same duration as each other, this describes how the control circuit sends a first signal for each LED driver circuit to the first-stage LED driver circuit in a multi-stage LED driver circuit. For example, 2N time periods with the same duration can be pre-set. The start time of these 2N time periods can be after the completion of the transmission of the global signal, and these 2N time periods are temporally consecutive. The first time period of these 2N time periods can be used as the first time period for the first-stage LED driver circuit, the second time period can be used as the second time period for the first-stage LED driver circuit, the third time period can be used as the first time period for the second-stage LED driver circuit, the fourth time period can be used as the second time period for the second-stage LED driver circuit, ..., the (2N-1)th time period can be used as the first time period for the Nth-stage LED driver circuit, and the 2Nth time period can be used as the second time period for the Nth-stage LED driver circuit. The control circuit can send the first data in the first signal for the first-level light-emitting diode driving circuit in the first time period, send the second data in the first signal for the first-level light-emitting diode driving circuit in the second time period, send the first data in the first signal for the second-level light-emitting diode driving circuit in the third time period, send the second data in the first signal for the second-level light-emitting diode driving circuit in the fourth time period,..., send the first data in the first signal for the N-level light-emitting diode driving circuit in the (2N-1)th time period, and send the second data in the first signal for the N-level light-emitting diode driving circuit in the 2N time period.

[0074] In addition, according to an example of the present disclosure, in step S202, for each level of LED driving circuit in the multi-level LED driving circuit, operation is performed according to the determined operation mode and the corresponding first signal, which may include three sub-steps, namely step S2021", step S2022", and step S2023". Specifically, in step S2021", first data for the LED driving circuit of the level is received within a first time period corresponding to the LED driving circuit of the level, and preset data is sent to its downstream circuit; in step S2022", an enable instruction in the first data for the LED driving circuit of the level is identified; in step S2023", second data for the LED driving circuit of the level is received within a second time period corresponding to the LED driving circuit of the level, and in response to the enable instruction, the data to be read stored in the LED driving circuit of the level is sent to its downstream circuit, wherein, for the last level of LED driving circuit, its downstream circuit is the control circuit; for each level of LED driving circuit except the last level of LED driving circuit, its downstream circuit is its next level of LED driving circuit.

[0075] Furthermore, in step S203, each stage of the LED driver circuit except the last stage, in response to completing the operation according to the determined operation mode and the corresponding first signal, sends a first signal for each subsequent stage of the LED driver circuit to the next stage of the LED driver circuit. For example, each stage of the LED driver circuit except the last stage, in response to completing the operation according to the determined operation mode and the corresponding first signal, may enter a state of waiting for the control circuit to indicate the end of the determined operation mode (e.g., waiting for the control circuit to change the level of the synchronization signal) and enter a bypass state. While in the bypass state, the first signals received for the subsequent stages of the LED driver circuit may not be processed, but instead the first signals for the subsequent stages of the LED driver circuit may be sent to the next stage of the LED driver circuit.

[0076] Specifically, while the upstream circuit sends first data (e.g., CT, OE) for the LED driver circuit of the stage to the LED driver circuit of the stage within a first time period corresponding to the LED driver circuit, the LED driver circuit of the stage can receive the first data for the LED driver circuit of the stage, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to its downstream circuit. The LED driver circuit of the stage can recognize the enable instruction in the first data for the LED driver circuit of the stage. While the upstream circuit sends second data (e.g., CT) for the LED driver circuit of the stage to the LED driver circuit of the stage within a second time period corresponding to the LED driver circuit of the stage, the LED driver circuit of the stage can receive the second data for the LED driver circuit of the stage, be in a read mode, and send the data to be read stored in the LED driver circuit of the stage to its downstream circuit. After outputting the data to be read, the LED driver circuit of the stage enters a bypass state, that is, sends the first signal received from the upstream circuit for the LED driver circuits of the stages following the LED driver circuit of the stage to the LED driver circuit of the next stage.

[0077] In other words, during the period when the control circuit sends first data (e.g., CT, OE) for the first-stage LED driver circuit to the first-stage LED driver circuit within a first time period corresponding to the first-stage LED driver circuit, the first-stage LED driver circuit can receive the first data for the first-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to the next-stage LED driver circuit. The first-stage LED driver circuit can recognize the enable instruction in the first data for the first-stage LED driver circuit. During the period when the control circuit sends second data (e.g., CT) for the first-stage LED driver circuit to the first-stage LED driver circuit within a second time period corresponding to the first-stage LED driver circuit, the first-stage LED driver circuit can receive the second data for the first-stage LED driver circuit, be in a read mode, and send the data to be read stored in the first-stage LED driver circuit to the next-stage LED driver circuit.

[0078] Furthermore, for each stage of the multi-stage LED driver circuit except for the first stage and the last stage, while the previous stage LED driver circuit transmits first data (e.g., CT, OE) for the next stage LED driver circuit to the next stage LED driver circuit within a first time period corresponding to the next stage LED driver circuit, the next stage LED driver circuit can receive the first data for the next stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to the next stage LED driver circuit. The next stage LED driver circuit can recognize the enable instruction in the first data for the next stage LED driver circuit. While the previous stage LED driver circuit transmits second data (e.g., CT) for the next stage LED driver circuit to the next stage LED driver circuit within a second time period corresponding to the next stage LED driver circuit, the next stage LED driver circuit can receive the second data for the next stage LED driver circuit, be in a read mode, and transmit the data to be read stored in the next stage LED driver circuit to the next stage LED driver circuit.

[0079] Furthermore, for the last-stage LED driver circuit in a multi-stage LED driver circuit, while the previous-stage LED driver circuit sends first data (e.g., CT, OE) for the last-stage LED driver circuit to the last-stage LED driver circuit within a first time period corresponding to the last-stage LED driver circuit, the last-stage LED driver circuit can receive the first data for the last-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to the control circuit. The last-stage LED driver circuit can recognize the enable instruction in the first data for the last-stage LED driver circuit. While the previous-stage LED driver circuit sends second data (e.g., CT) for the last-stage LED driver circuit to the last-stage LED driver circuit within a second time period corresponding to the last-stage LED driver circuit, the last-stage LED driver circuit can receive the second data for the last-stage LED driver circuit, be in a read mode, and send the data to be read stored in the last-stage LED driver circuit to the control circuit.

[0080] In addition, before step S202, the method 200 may further include: for each stage of the multi-stage LED driving circuit except the first stage of the LED driving circuit, sending data received from the previous stage of the LED driving circuit to its downstream circuit in one or more preset time periods before the first time period corresponding to the LED driving circuit of the stage. For example, for each stage of the multi-stage LED driving circuit except the first stage of the LED driving circuit, in a first time period included in the one or more preset time periods before the first time period corresponding to the LED driving circuit of the stage, the method 200 may receive preset data from the previous stage of the LED driving circuit and send the preset data to the downstream circuit; and in a second time period included in the one or more preset time periods, receive data to be read from the previous stage of the LED driving circuit from the previous stage of the LED driving circuit and send the data to be read from the previous stage of the LED driving circuit to the downstream circuit.

[0081] In addition, after the control circuit sends the global signal and the first signal for each level of the LED driving circuit to the first level of the multi-level LED driving circuit, the method 200" may further include step S204". In step S204", the control circuit sends specific data to the first level of the LED driving circuit in the multi-level LED driving circuit. According to the above description, after outputting the data to be read, each level of the LED driving circuit is in a bypass state. Therefore, each level of the LED driving circuit can transmit the specific data to its downstream circuit. Specifically, each level of the LED driving circuit except the last level of the LED driving circuit can transmit the specific data to its next level of the LED driving circuit; the last level of the LED driving circuit can feed back the specific data to the control circuit.

[0082] In addition, after step S204", method 200" may further include step S205". In step S205", the control circuit instructs the light-emitting diode driving circuits at each level to end the determined operation mode. For example, the control circuit may change the level of the synchronization signal it sends to the light-emitting diode driving circuits at each level (for example, from a high level to a low level, or from a low level to a high level). Accordingly, the light-emitting diode driving circuits at each level may end the current operation mode after detecting the change in the level of the synchronization signal.

[0083] Furthermore, the preset data mentioned above may be data having a preset value. The preset value may be, for example, 0 or 1. The specific data mentioned above may be, for example, data related to clock training (CT). Furthermore, CT and / or OE may serve as the header of a data packet. Furthermore, the data to be read may be display data (e.g., grayscale data) or a set value.

[0084] The following example shows that the display drive system includes a control circuit and a three-stage light-emitting diode drive circuit and performs a read operation. Figure 5 , the specific process of method 200 is described again.

[0085] Figure 5 FIG. 1 shows a schematic diagram of a process in which a display driver system performs a reading operation. Figure 5 As shown, the control circuit sequentially sends a global signal, a first signal for each level of LED driver circuits, and specific data to the first-level LEDs. The global signal includes data (CT) related to clock training, a command transmission indication (CS), and a read instruction (RDCMD). The first signal for the first-level LED driver circuit may include first data (CT, OE) to be transmitted in a first time period (T1) corresponding to the first-level LED driver circuit and second data (CT) to be transmitted in a second time period (T2) corresponding to the first-level LED driver circuit. The first signal for the second-level LED driver circuit may include first data (CT, OE) to be transmitted in a first time period (T1) corresponding to the second-level LED driver circuit and second data (CT) to be transmitted in a second time period (T2) corresponding to the second-level LED driver circuit. The first signal for the third-level LED driver circuit may include first data (CT, OE) to be transmitted in a first time period (T1) corresponding to the third-level LED driver circuit and second data (CT) to be transmitted in a second time period (T2) corresponding to the third-level LED driver circuit. The specific data is data (CT) related to clock training.

[0086] In addition, if Figure 5As shown, while the control circuit transmits CT in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and RD CMD in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write RD CMD and be in a bypass state. Furthermore, while the first-stage LED driver circuit transmits CT in the global signal to the second-stage LED driver circuit, the second-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the first-stage LED driver circuit transmits CS and RD CMD in the global signal to the second-stage LED driver circuit, the second-stage LED driver circuit can write RD CMD and be in a bypass state. Furthermore, while the second-stage LED driver circuit transmits CT in the global signal to the third-stage LED driver circuit, the third-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the second-stage LED driver circuit transmits CS and RD CMD in the global signal to the third-stage LED driver circuit, the third-stage LED driver circuit can write CMD and be in a bypass state. The third-stage light-emitting diode driving circuit can feed back the received global signal to the control circuit.

[0087] Furthermore, while the control circuit transmits first data (e.g., CT, OE) for the first-stage LED driver circuit to the first-stage LED driver circuit within a first time period corresponding to the first-stage LED driver circuit, the first-stage LED driver circuit may receive the first data for the first-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output 0 to the second-stage LED driver circuit. The second-stage LED driver circuit receives 0 from the first-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output 0 to the third-stage LED driver circuit. The third-stage LED driver circuit receives 0 from the second-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output 0 to the control circuit.

[0088] Furthermore, while the control circuit transmits second data (e.g., CT) for the first-stage LED driver circuit to the first-stage LED driver circuit within a second time period corresponding to the first-stage LED driver circuit, the first-stage LED driver circuit may receive the second data for the first-stage LED driver circuit and, in a read mode, transmit the data to be read stored in the first-stage LED driver circuit to the second-stage LED driver circuit. The second-stage LED driver circuit receives the data to be read from the first-stage LED driver circuit and, in a bypass state, transmits the data to be read from the first-stage LED driver circuit to the third-stage LED driver circuit. The third-stage LED driver circuit receives the data to be read from the first-stage LED driver circuit from the second-stage LED driver circuit and, in a bypass state, transmits the data to be read from the first-stage LED driver circuit to the control circuit.

[0089] After the first-stage LED driver circuit outputs the data to be read, the first-stage LED driver circuit enters a bypass state. Therefore, the first signal received from the control circuit and intended for the second-stage and third-stage LED driver circuits following the first-stage LED driver circuit is sent to the second-stage LED driver circuit. During a first time period corresponding to the second-stage LED driver circuit, the second-stage LED driver circuit performs an operation similar to the operation performed by the first-stage LED driver circuit during the first time period corresponding to the first-stage LED driver circuit, and the third-stage LED driver circuit performs an operation similar to the operation performed by the third-stage LED driver circuit during the first time period corresponding to the first-stage LED driver circuit. During a second time period corresponding to the second-stage LED driver circuit, the second-stage LED driver circuit performs an operation similar to the operation performed by the first-stage LED driver circuit during the second time period corresponding to the first-stage LED driver circuit, and the third-stage LED driver circuit performs an operation similar to the operation performed by the third-stage LED driver circuit during the second time period corresponding to the first-stage LED driver circuit.

[0090] After the second-stage LED driver circuit outputs the data to be read, the second-stage LED driver circuit enters a bypass state. Therefore, the first signal received from the control circuit and intended for the third-stage LED driver circuit following the second-stage LED driver circuit is sent to the third-stage LED driver circuit. During a first time period corresponding to the third-stage LED driver circuit, the third-stage LED driver circuit performs an operation similar to that performed by the first-stage LED driver circuit during the first time period corresponding to the first-stage LED driver circuit. During a second time period corresponding to the third-stage LED driver circuit, the third-stage LED driver circuit performs an operation similar to that performed by the first-stage LED driver circuit during the second time period corresponding to the first-stage LED driver circuit.

[0091] After outputting the data to be read, each stage of the LED driver circuit is in a bypass state. Therefore, the first stage LED driver circuit can send the CT received from the control circuit to the second stage LED driver circuit, the second stage LED driver circuit can send the CT received from the first stage LED driver circuit to the third stage LED driver circuit, and the third stage LED driver circuit can feed back the CT received from the second stage LED driver circuit to the control circuit.

[0092] Afterwards, the control circuit may change the level of the synchronization signal (not shown in the figure) sent to each level of the LED driving circuit to instruct the LED driving circuits at each level to end the reading mode.

[0093] In this way, the data to be read can be read out from each stage of the LED driving circuit in sequence until the level of the synchronization signal changes. In this way, there is no need to spend additional pins or chip select signals or other judgment mechanisms to determine the LED driving circuit corresponding to the data.

[0094] It should be understood that the above examples are based on ideally aligned timing, i.e., there is no delay in the signal transmission process. When there is a delay in the signal transmission process, the signal may be delayed step by step between the control circuit and each level of the LED driver circuit (e.g., Figure 4 However, this delay does not affect the operation of the control circuit and the various light emitting diode driving circuits described above.

[0095] In addition, in the present disclosure, for a write operation or a read operation, the control circuit can output CT (CT in the global signal) to identify the start of the operation, and output CT (specific data) to identify the end of the operation. That is, between the start and end of the operation, all data output by the control circuit can be regarded as a packet corresponding to the operation, which corresponds to the portion of a horizontal display line on the display panel that is driven by the various levels of the light-emitting diode driving circuit. Before or after this operation, other data output by the control circuit is a packet corresponding to the same or different operation as the operation.

[0096] Furthermore, during a write operation or a read operation, while the final-stage LED driver circuit transmits the received global signal to the control circuit, the control circuit does not continue to output subsequent signals until it receives the global signal fed back from the final-stage LED driver circuit. During a complete write operation or a read operation, the control circuit can determine the signals to be transmitted and how to transmit them. For example, the control circuit can determine a predetermined number of CTs, a predetermined number of CSs, a predetermined number of CMDs, and the order in which these CTs, CSs, and CMDs should be transmitted.

[0097] The following will be combined Figure 6 To describe the state diagram of the light emitting diode driving circuit in the write mode / read mode. Figure 6 FIG2 shows a state diagram of the light emitting diode driving circuit in a write mode / read mode according to an embodiment of the present disclosure. Tx refers to the transmitting end (Tx) of the light emitting diode driving circuit.

[0098] like Figure 6 As shown, in step S1, the LED driving circuit receives CT from the upstream circuit, and the transmitting end (Tx) is in the bypass state. Then, by receiving CS, it is indicated that the transmission command (CMD) is about to begin. Then, in step S2, the LED driving circuit receives the command (CMD) from the upstream circuit, and the transmitting end (Tx) is in the bypass state.

[0099] If the received command is a write command (WR CMD), in step S3, the LED driver circuit waits for DS, and the transmitter (Tx) outputs 0. Then, receiving DS indicates that the data to be written is about to be transmitted. Then, in step S4, the LED driver circuit receives the data to be written, and the transmitter (Tx) outputs 0. After writing the data to be written, in step S5, the LED driver circuit waits for the synchronization signal level to change (also known as being in an idle state), and the transmitter (Tx) enters a bypass state.

[0100] If the received command is a read command (RD CMD), in step S6, the LED driver circuit may start a first timer for a first time period (T1). During T1, the LED driver circuit may wait for an OE, and the transmitter (Tx) may output 0. When T1 expires, in step S7, the LED driver circuit may determine whether an OE was received during T1. If so, the LED driver circuit executes step S8; if not, the LED driver circuit executes step S9.

[0101] In step S8, the LED driver circuit may start a second timer for a second time period (T2). During T2, the transmitter (Tx) of the LED driver circuit may output the data stored in the LED driver circuit. When T2 expires, the LED driver circuit stops outputting data. The LED driver circuit then executes step S5 above.

[0102] In addition, in step S9, the LED driving circuit may also start a second timer, which lasts for a second time period (T2). During T2, the transmitter (Tx) is in a bypass state. When T2 expires, the LED driving circuit returns to execute the above step S6.

[0103] At this point, the LED driving circuit completes one write / read operation. Afterwards, the LED driving circuit can return to step S1 again through the level change of the synchronization signal to prepare for the next write / read operation.

[0104] In the present disclosure, the display driver system can enter the power saving mode after completing one or more write / read operations, or can enter the power saving mode after starting the protection mode (described below). The power saving mode can save power and effectively reduce chip power consumption.

[0105] According to a first example of the present disclosure, the LED driver circuit can passively enter the power saving mode, for example, by following an instruction from a control circuit. Furthermore, according to a second example of the present disclosure, the LED driver circuit can actively enter the power saving mode, for example, by determining whether to enter the power saving mode by determining whether the duration of a period during which it receives specific data from its upstream circuit is greater than a preset threshold.

[0106] The following will be combined Figure 7 A method for a display driving system to enter a power saving mode according to a first example will be described. Figure 7 FIG. 1 is a flow chart of a method for a display driving system to enter a power saving mode according to a first example of an embodiment of the present disclosure. Figure 2A The method 200 shown, or Figure 2B The method 200' shown, or Figure 2C The method 200 shown is then executed Figure 7 Method 700 is shown.

[0107] like Figure 7 As shown, method 700 includes four steps: step S701, step S702, step S703, and step S704. Specifically, in step S701, the control circuit sends another global signal to the first-stage LED driver circuit in the multi-stage LED driver circuit, where the other global signal includes an instruction for indicating another operating mode for each stage of the LED driver circuit. In step S702, each stage of the LED driver circuit determines another operating mode based on the other global signal. In step S703, each stage of the LED driver circuit operates according to the other operating mode. In step S704, each stage of the LED driver circuit, except for the last stage of the LED driver circuit, sends the other global signal to the LED driver circuit in the next stage.

[0108] It should be noted that the above steps S701, S702, S703 and S704 may be performed sequentially or not. For example, step S701 may be performed first, followed by step S702 and step S704, and finally step S703.

[0109] According to an example of the present disclosure, in step S701, the instruction in another global signal for indicating another operating mode of each stage of the light-emitting diode driver circuit may be a power-saving instruction (Save Command, which may be abbreviated as SVCMD), and the other operating mode may be a power-saving mode. Alternatively, the power-saving instruction may be carried in a write instruction.

[0110] In addition, another global signal may further include data related to clock training (CT) and a command transmission indication (CS). In this case, the data related to clock training (CT), the command transmission indication (CS) and the power saving instruction may be transmitted in sequence.

[0111] While the upstream circuit is transmitting CT, another global signal, to the LED driver circuit, the LED driver circuit can be in a waiting state for CT and in a bypass state. Furthermore, while the upstream circuit is transmitting CS and SV CMD, another global signal, to the LED driver circuit, the LED driver circuit can write SV CMD and be in a bypass state. The final-stage LED driver circuit can feed back the received global signal to the control circuit.

[0112] In other words, while the control circuit transmits CT from another global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and SV CMD from another global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write SV CMD and be in a bypass state. Furthermore, while the upper-stage LED driver circuit transmits CT from another global signal to its lower-stage LED driver circuit, the lower-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the upper-stage LED driver circuit transmits CS and SV CMD from another global signal to its lower-stage LED driver circuit, the lower-stage LED driver circuit can write SV CMD and be in a bypass state.

[0113] In addition, in step S702 , each stage of the LED driving circuit may determine, according to the other global signal, that the operation mode corresponding to the instruction is the power saving mode.

[0114] Furthermore, according to an example of the present disclosure, in step S703 , each stage of the multi-stage LED driving circuit operates according to another operation mode, which may include: the LED driving circuit of this stage at least disabling a data transmission function.

[0115] Alternatively, in step S703, each stage of the multi-stage LED driver circuit operating according to another operating mode may include: the LED driver circuit in that stage sending preset data to its downstream circuit, wherein for the last stage of the LED driver circuit, its downstream circuit is the control circuit; for each stage of the LED driver circuit except the last stage of the LED driver circuit, its downstream circuit is the LED driver circuit in the next stage. The preset data described here may be data having a preset value, such as 0, because transmitting data 0 to the next stage of the LED driver circuit is more power-efficient than transmitting data 1.

[0116] In this situation, since the first-stage LED driver circuit has already received the power-saving instruction from the control circuit and entered the power-saving mode, even if the control circuit sends a CT to it, the first-stage LED driver circuit can output the preset data 0 to the next-stage LED driver circuit. In other words, the first-stage LED driver circuit is performing power-saving data transmission. In addition, each stage of LED driver circuit other than the first stage has also received the power-saving instruction from the control circuit and entered the power-saving mode. Therefore, it can output 0 to the next-stage LED driver circuit. In other words, each stage of LED driver circuit other than the first stage is performing power-saving data transmission.

[0117] Furthermore, further, part of the circuits in the transmitter circuit of each stage of the light emitting diode driving circuit may be appropriately shut down (so that it does not operate) to achieve a better power saving effect.

[0118] Furthermore, after step S704, method 700 may further include step S705. In step S705, the control circuit instructs the LED driver circuits of each stage to end the power saving mode. For example, the control circuit may change the level of the synchronization signal it sends to the LED driver circuits of each stage (e.g., from a high level to a low level, or from a low level to a high level). Accordingly, the LED driver circuits of each stage may end the power saving mode after detecting the change in the level of the synchronization signal. After ending the power saving mode, the display driver system may prepare for the next write / read operation.

[0119] The following example shows that the display drive system includes a control circuit and a three-stage light-emitting diode drive circuit and performs power saving operation. Figure 8 , describe the specific process of method 700 again.

[0120] Figure 8 A schematic diagram showing the process of the display driving system entering the power saving mode is shown. Figure 8 FIG. 4 shows that the display driver system enters the power saving mode after completing a write operation. Figure 8 As shown, after the display driving system completes the write operation, the control circuit can send another global signal to the first light-emitting diode driving circuit, and the other global signal includes data related to clock training (CT), instruction transmission indication (CS) and power saving instruction (SV CMD), and transmits data related to clock training (CT), instruction transmission indication (CS) and power saving instruction in sequence.

[0121] While the control circuit transmits CT from another global signal to the first-stage LED driver circuit, the first-stage LED driver circuit may be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and SV CMD from another global signal to the first-stage LED driver circuit, the first-stage LED driver circuit may write SV CMD and be in a bypass state. Furthermore, while the first-stage LED driver circuit transmits CT from another global signal to the second-stage LED driver circuit, the second-stage LED driver circuit may be in a waiting state for CT and in a bypass state. While the first-stage LED driver circuit transmits CS and SV CMD from another global signal to the second-stage LED driver circuit, the second-stage LED driver circuit may write SV CMD and be in a bypass state. Furthermore, while the second-stage LED driver circuit transmits CT from another global signal to the third-stage LED driver circuit, the third-stage LED driver circuit may be in a waiting state for CT and in a bypass state. While the second-stage LED driver circuit transmits CS and SVCMD from another global signal to the third-stage LED driver circuit, the third-stage LED driver circuit may write SV CMD and be in a bypass state. In addition, the third-stage LED driving circuit may feed back another received global signal to the control circuit.

[0122] The first-stage, second-stage, and third-stage LED driver circuits have all received the power-saving instruction from the control circuit and can enter the power-saving mode. At this time, if the control circuit sends CT to the first-stage LED driver circuit, the first-stage LED driver circuit can output 0 to the second-stage LED driver circuit, the second-stage LED driver circuit can output 0 to the third-stage LED driver circuit, and the third-stage LED driver circuit can output 0 to the control circuit.

[0123] The control circuit can change the level of the synchronization signal it sends to the LED drive circuits at each level (such as Figure 8 As shown, the level changes from high to low. Accordingly, the LED driving circuits at each level can end the power saving mode after detecting the change in the level of the synchronization signal. After the power saving mode ends, the display driving system can prepare for the next write operation.

[0124] It should be understood that the above examples are based on ideally aligned timing, i.e., there is no delay in the signal transmission process. When there is a delay in the signal transmission process, the signal may be delayed step by step between the control circuit and each level of the LED driver circuit (e.g., Figure 4 However, this delay does not affect the operation of the control circuit and the various light emitting diode driving circuits described above.

[0125] The following will be combined Figure 9 A method for a display driving system to enter a power saving mode according to a second example will be described. Figure 9 FIG. 1 is a flow chart of a method for a display driving system to enter a power saving mode according to a second example of an embodiment of the present disclosure. Figure 2A The method 200 shown, or Figure 2B The method 200' shown, or Figure 2C The method 200 shown is then executed Figure 9 Method 900 is shown.

[0126] like Figure 9 As shown, method 900 includes three steps: step S901, step S902, and step S903. Specifically, in step S901, each LED driver circuit stage can determine whether the duration of the time period during which it receives specific data from its upstream circuit is greater than a preset threshold. If the duration of the time period during which the LED driver circuit stage receives specific data from its upstream circuit is greater than the preset threshold, in step S902, the LED driver circuit stage changes the determined operating mode to power saving mode. If the duration of the time period during which the LED driver circuit stage receives specific data from its upstream circuit is not greater than the preset threshold, in step S903, the LED driver circuit stage does not change the determined operating mode to power saving mode. For example, the specific data can be CT. For the first-stage LED driver circuit, its upstream circuit is the control circuit; for each LED driver circuit stage other than the first-stage LED driver circuit, its upstream circuit is the LED driver circuit stage above it.

[0127] According to one example of the present disclosure, each LED driver circuit may start a timer upon detecting specific data, and the timer duration is a preset threshold. After the preset threshold time period expires, if the LED driver circuit still detects the specific data, the LED driver circuit may change the current operating mode to the power saving mode.

[0128] The specific data mentioned here may be data having a preset value, and the preset value may be 0 or 1, for example.

[0129] Furthermore, after step S902 or S903, method 900 may further include step S904. In step S904, the control circuit instructs the LED driver circuits of each stage to end the power saving mode. For example, the control circuit may change the level of the synchronization signal it sends to the LED driver circuits of each stage (e.g., from a high level to a low level, or from a low level to a high level). Accordingly, the LED driver circuits of each stage may end the power saving mode upon detecting the change in the level of the synchronization signal.

[0130] After the power saving mode ends, the display driving system can prepare for the next write / read operation.

[0131] In the present disclosure, the display driver system can enter the power-on protection mode after power-on, and then enter the write / read mode after the display driver system is operating normally. In this way, the chip's ESD tolerance can be greatly improved, thereby extending the chip's life.

[0132] The following will be combined Figure 10 To describe the specific process of the display driver system performing power-on protection operations. Figure 10 FIG. 1 is a flow chart of a method for performing power-on protection operation of a display driving system according to an embodiment of the present disclosure. Figure 10 As shown, method 1000 includes step S1001, step S1002 and step S1003.

[0133] Specifically, the control circuit may execute step S1001 after powering on. In step S1001, the control circuit changes the level of the synchronization signal it sends to each level of the LED driver circuit according to a preset period. For example, the control circuit may change the level of the synchronization signal it sends to each level of the LED driver circuit from a high level to a low level according to a preset period, or the control circuit may change the level of the synchronization signal it sends to each level of the LED driver circuit from a low level to a high level according to a preset period.

[0134] Furthermore, after powering on and before sending a global signal and a first signal for each stage of the LED driver circuit to the first stage of the multi-stage LED driver circuit, the control circuit may execute step S1002. In step S1002, the control circuit sends first preset data to the first stage of the LED driver circuit.

[0135] Then, in step S1003, for each level of the light-emitting diode driving circuit in the multi-level light-emitting diode driving circuit, when the first preset data is not received or when the first preset data is received but the level of the synchronization signal does not change for a preset number of times (for example, 2 times), the second preset data is sent to its downstream circuit; when the first preset data is received and the level of the synchronization signal changes for a preset number of times, the first preset data is sent to its downstream circuit.

[0136] As described above, for the last-stage LED driving circuit in the multi-stage LED driving circuit, its downstream circuit is the control circuit, and for each stage of the LED driving circuit except the last-stage LED driving circuit in the multi-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit.

[0137] Then, after step S1003, in response to the control circuit receiving the first preset data from the last-level LED driving circuit, the control circuit starts to send the global signal and the first signal for each level of LED driving circuit to the first-level LED driving circuit in the multi-level LED driving circuit for writing / reading operations.

[0138] In the above manner, until the control circuit receives the first preset data fed back by the last-stage LED driving circuit, the control circuit and the LED driving circuits at all stages enter the normal state together to perform the write / read operation.

[0139] The values ​​of the first preset data and the second preset data described above are different. For example, the value of the first preset data may be 0, and the value of the second preset data may be 1. Alternatively, the value of the first preset data may be 1, and the value of the second preset data may be 0.

[0140] The following example shows that the display drive system includes a control circuit and a three-stage light-emitting diode drive circuit and performs a power-on protection operation. Figure 11 and Figure 12 , describe the specific process of method 1000 again.

[0141] Figure 11 The figure shows the process of the display drive system entering the power-on protection mode, wherein the control circuit is powered on first, and then the light emitting diode drive circuits of each level are powered on. Figure 11As shown, the control circuit is powered on first and, after power-on, continuously transmits 1 to the first-stage LED driver circuit. If the first-stage LED driver circuit does not receive a 1, or receives a 1 but the synchronization signal level does not change twice, it transmits a 0 to the second-stage LED driver circuit. Similarly, if the second-stage LED driver circuit does not receive a 1, or receives a 1 but the synchronization signal level does not change twice, it transmits a 0 to the third-stage LED driver circuit. If the third-stage LED driver circuit does not receive a 1, or receives a 1 but the synchronization signal level does not change twice, it transmits a 0 to the control circuit. Furthermore, if the first-stage LED driver circuit receives a 1 and the synchronization signal level changes twice, it transmits a 1 to the second-stage LED driver circuit. Similarly, if the second-stage LED driver circuit receives a 1 and the synchronization signal level changes twice, it transmits a 1 to the third-stage LED driver circuit. If the third-stage LED driver circuit receives a 1 and the synchronization signal level changes twice, it transmits a 1 to the control circuit. After receiving the feedback 1 from the third-stage LED driving circuit, the control circuit and the LED driving circuits at each stage can enter the normal state together to perform write / read operations (for example, transmitting CT in the global signal).

[0142] Figure 12 Another schematic diagram of the process of the display driving system entering the power-on protection mode is shown. Figure 12 and Figure 11 Similar, except that Figure 12 In the example, the LED drive circuits of each level are powered on first, and the control circuit is powered on later.

[0143] like Figure 12As shown, each LED driver circuit is powered on first and waits for the first specific data 1 after powering up. The control circuit is then powered on and continuously transmits 1 to the first-stage LED driver circuit. If the first-stage LED driver circuit does not receive a 1, or receives a 1 but the synchronization signal level does not change twice, it transmits a 0 to the second-stage LED driver circuit. Similarly, if the second-stage LED driver circuit does not receive a 1, or receives a 1 but the synchronization signal level does not change twice, it transmits a 0 to the third-stage LED driver circuit. If the third-stage LED driver circuit does not receive a 1, or receives a 1 but the synchronization signal level does not change twice, it transmits a 0 to the control circuit. Furthermore, if the first-stage LED driver circuit receives a 1 and the synchronization signal level changes twice, it transmits a 1 to the second-stage LED driver circuit. Similarly, if the second-stage LED driver circuit receives a 1 and the synchronization signal level changes twice, it transmits a 1 to the third-stage LED driver circuit. If the third-stage LED driver circuit receives a 1 and the synchronization signal level changes twice, it transmits a 1 to the control circuit. After receiving the feedback 1 from the third-stage LED driving circuit, the control circuit and the LED driving circuits at each stage can enter the normal state together to perform write / read operations (for example, transmitting CT in the global signal).

[0144] It should be understood that the above examples are based on ideally aligned timing, i.e., there is no delay in the signal transmission process. When there is a delay in the signal transmission process, the signal may be delayed step by step between the control circuit and each level of the LED driver circuit (e.g., Figure 4 However, this delay does not affect the operation of the control circuit and the various light emitting diode driving circuits described above.

[0145] So far, the specific process of the display driver system performing write / read / power-saving / power-on protection operations according to the signal transmission protocol has been described. In this process, the signals transmitted between the control circuit and the first-stage LED driver circuit, between each stage of the LED driver circuit, and between the final stage of the LED driver circuit and the control circuit are all data signals. For example, the global signal and the first signal for each stage of the LED driver circuit are all data signals.

[0146] Furthermore, clock signals can be transmitted between the control circuit and the first-stage LED driver circuit, between each stage of the LED driver circuit, and between the last stage of the LED driver circuit and the control circuit. For example, the control circuit can send a clock signal to the first-stage LED driver circuit, and each stage of the LED driver circuit, except the last stage, can send the clock signal to the next stage of the LED driver circuit.

[0147] According to one example of the present disclosure, data signals and / or clock signals can be transmitted via differential lines. Specifically, the control circuit can send a global signal and a first signal for each stage of the LED driver circuit to the first stage of the multi-stage LED driver circuit via differential lines. In addition, each stage of the LED driver circuit can send a global signal and a first signal for each stage of the LED driver circuit to the next stage of the LED driver circuit via differential lines. In addition, the control circuit can send a clock signal to the first stage of the LED driver circuit via differential lines, and each stage of the LED driver circuit can send the clock signal to the next stage of the LED driver circuit via differential lines.

[0148] Transmitting data and clock signals differentially allows for smaller voltage swings (hundreds of millivolts), effectively suppressing noise and increasing signal transmission speed. Furthermore, transmitting the clock signal in series can reduce clock signal distortion.

[0149] Furthermore, in the present disclosure, each stage of the LED driver circuit can be used to drive a display using micro LEDs (Micro LEDs) as display pixels. Micro LEDs differ from ordinary LEDs in that they are smaller, for example, only on the order of 1 to 10 μm. Therefore, micro LEDs can make LED structures thinner, more miniaturized, and more array-based, providing extremely high color saturation.

[0150] Through the method for display driving system of the above embodiment, through a specific signal transmission protocol, each light-emitting diode driving circuit can identify the data that the control circuit wants to send to itself, thereby not requiring additional pins or chip select signals to determine the corresponding light-emitting diode driving circuit, avoiding the use of SPI and thus avoiding certain defects caused by SPI. In addition, a power-saving mode is set for the display driving system, and the power-saving mode can save power and effectively reduce the power consumption of the chip. In addition, a power-on protection mode is set for the display driving system, and the power-on protection mode can greatly improve the ESD tolerance of the chip, thereby extending the life of the chip. In addition, by transmitting the data signal and the clock signal in a differential manner, the data signal and the clock signal can be transmitted with a smaller voltage swing (about hundreds of mV), thereby effectively suppressing the influence of noise and improving the signal transmission speed. In addition, transmitting the clock signal in series can improve the distortion of the clock signal.

[0151] Hereinafter, a display driving system according to an embodiment of the present disclosure will be described. In the present disclosure, the display driving system may include a control circuit and a multi-stage light emitting diode driving circuit connected in cascade. As described above, Figure 1 As shown, the display driving system 100 may include a control circuit 110 and three-stage LED driving circuits, which are a first-stage LED driving circuit 120-1, a second-stage LED driving circuit 120-2, and a third-stage LED driving circuit 120-3.

[0152] In the present disclosure, a control circuit is configured to send a global signal and a first signal for each stage of the LED driver circuit to a first-stage LED driver circuit in a multi-stage LED driver circuit, wherein the global signal includes an instruction for indicating the operating mode of each stage of the LED driver circuit. Each stage of the LED driver circuit is configured to determine the operating mode corresponding to the instruction based on the global signal, identify the first signal corresponding to the LED driver circuit of that stage, and operate according to the determined operating mode and the corresponding first signal. Each stage of the LED driver circuit, except for the last stage of the LED driver circuit, is configured to send the global signal to the LED driver circuit of the next stage, and in response to completing the operation according to the determined operating mode and the corresponding first signal, send the first signal for each stage of the LED driver circuit after the LED driver circuit of the next stage to the LED driver circuit of the next stage.

[0153] In the write mode, while the control circuit transmits CT in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and WR CMD in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write WR CMD and be in a bypass state. In addition, while the upper-stage LED driver circuit transmits CT in the global signal to the lower-stage LED driver circuit, the lower-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the upper-stage LED driver circuit transmits CS and WR CMD in the global signal to the lower-stage LED driver circuit, the lower-stage LED driver circuit can write WR CMD and be in a bypass state.

[0154] In addition, for each level of LED driving circuit in the multi-level LED driving circuit, it can be configured to send preset data to its downstream circuit when the data to be written for the LED driving circuit at this level is not received; when the data to be written for the LED driving circuit at this level is received, write the data to be written for the LED driving circuit at this level and send the preset data to the downstream circuit; wherein, for the last level of LED driving circuit in the multi-level LED driving circuit, its downstream circuit is the control circuit; for each level of LED driving circuit in the multi-level LED driving circuit except the last level of LED driving circuit, its downstream circuit is the LED driving circuit at the next level.

[0155] Furthermore, each stage of the LED driver circuit, except for the last stage, may be configured to, in response to completing operations according to the determined operating mode and the corresponding first signal, send a first signal for each subsequent stage of the LED driver circuit to the next stage of the LED driver circuit. For example, each stage of the LED driver circuit, except for the last stage of the LED driver circuit, may, in response to completing operations according to the determined operating mode and the corresponding first signal, enter a state of waiting for an instruction from the control circuit to terminate the determined operating mode (e.g., waiting for the control circuit to change the level of the synchronization signal) and enter a bypass state. While in the bypass state, the first signals received for the subsequent stages of the LED driver circuit may not be processed, but instead the first signals for the subsequent stages of the LED driver circuit may be sent to the next stage of the LED driver circuit.

[0156] Furthermore, the control circuit can be further configured to send specific data to the first-stage LED driver circuit in the multi-stage LED driver circuit after the control circuit sends a global signal and a first signal specific to each stage of the LED driver circuit to the first-stage LED driver circuit. As described above, after writing the data to be written, each stage of the LED driver circuit is in a bypass state. Therefore, each stage of the LED driver circuit can transmit the specific data to its downstream circuit. Specifically, each stage of the LED driver circuit, except for the last stage, can transmit the specific data to the next-stage LED driver circuit; the last stage of the LED driver circuit can then feed the specific data back to the control circuit.

[0157] Furthermore, the control circuit can be configured to instruct the LED driver circuits of each stage to terminate a determined operating mode. For example, the control circuit can change the level of a synchronization signal it sends to the LED driver circuits of each stage (e.g., from a high level to a low level, or from a low level to a high level). Accordingly, the LED driver circuits of each stage can terminate their current operating mode upon detecting the change in the level of the synchronization signal.

[0158] In read mode, while the control circuit transmits CT in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and RD CMD in the global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write RD CMD and be in a bypass state. Furthermore, while the previous-stage LED driver circuit transmits CT in the global signal to the next-stage LED driver circuit, the next-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the previous-stage LED driver circuit transmits CS and RD CMD in the global signal to the next-stage LED driver circuit, the next-stage LED driver circuit can write RD CMD and be in a bypass state. The last-stage LED driver circuit can feed back the received global signal to the control circuit.

[0159] In this mode, the control circuit can be configured to send a first signal for the i-th level light-emitting diode driving circuit in a preset time period corresponding to the i-th level light-emitting diode driving circuit, respectively, wherein the preset time period includes a first time period (for example, T1) and a second time period (for example, T2), and the control circuit sends the first data for the i-th level light-emitting diode driving circuit in the first time period and sends the second data for the i-th level light-emitting diode driving circuit in the second time period, wherein the multi-level light-emitting diode driving circuit is an N-level light-emitting diode driving circuit, N is an integer greater than or equal to 3, and i is an integer greater than or equal to 1 and less than or equal to N.

[0160] In addition, according to an example of the present disclosure, each level of LED driving circuit in a multi-level LED driving circuit can be configured to receive first data for the LED driving circuit within a first time period corresponding to the LED driving circuit of the level, and send preset data to its downstream circuit; identify an enable instruction in the first data for the LED driving circuit of the level; receive second data for the LED driving circuit of the level within a second time period corresponding to the LED driving circuit of the level, and send the data to be read stored in the LED driving circuit of the level to its downstream circuit in response to the enable instruction, wherein, for the last level of LED driving circuit, its downstream circuit is the control circuit; for each level of LED driving circuit except the last level of LED driving circuit, its downstream circuit is its next level of LED driving circuit.

[0161] Furthermore, each stage of the LED driver circuit, except for the last stage, may be further configured to, in response to completing operations according to the determined operating mode and the corresponding first signal, send a first signal for each subsequent stage of the LED driver circuit to the next stage of the LED driver circuit. For example, each stage of the LED driver circuit, except for the last stage of the LED driver circuit, may, in response to completing operations according to the determined operating mode and the corresponding first signal, enter a state of waiting for an instruction from the control circuit to terminate the determined operating mode (e.g., waiting for the control circuit to change the level of the synchronization signal) and enter a bypass state. While in the bypass state, the first signals received for the subsequent stages of the LED driver circuit may not be processed, but instead the first signals for the subsequent stages of the LED driver circuit may be sent to the next stage of the LED driver circuit.

[0162] Specifically, during a period in which the control circuit sends first data (e.g., CT, OE) for the first-stage LED driver circuit to the first-stage LED driver circuit within a first time period corresponding to the first-stage LED driver circuit, the first-stage LED driver circuit can receive the first data for the first-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to the next-stage LED driver circuit. The first-stage LED driver circuit can recognize the enable instruction in the first data for the first-stage LED driver circuit. During a period in which the control circuit sends second data (e.g., CT) for the first-stage LED driver circuit to the first-stage LED driver circuit within a second time period corresponding to the first-stage LED driver circuit, the first-stage LED driver circuit can receive the second data for the first-stage LED driver circuit, be in a read mode, and send the data to be read stored in the first-stage LED driver circuit to the next-stage LED driver circuit.

[0163] Furthermore, for each stage of the multi-stage LED driver circuit except for the first stage and the last stage, while the previous stage LED driver circuit transmits first data (e.g., CT, OE) for the next stage LED driver circuit to the next stage LED driver circuit within a first time period corresponding to the next stage LED driver circuit, the next stage LED driver circuit can receive the first data for the next stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to the next stage LED driver circuit. The next stage LED driver circuit can recognize the enable instruction in the first data for the next stage LED driver circuit. While the previous stage LED driver circuit transmits second data (e.g., CT) for the next stage LED driver circuit to the next stage LED driver circuit within a second time period corresponding to the next stage LED driver circuit, the next stage LED driver circuit can receive the second data for the next stage LED driver circuit, be in a read mode, and transmit the data to be read stored in the next stage LED driver circuit to the next stage LED driver circuit.

[0164] Furthermore, for the last-stage LED driver circuit in a multi-stage LED driver circuit, while the previous-stage LED driver circuit sends first data (e.g., CT, OE) for the last-stage LED driver circuit to the last-stage LED driver circuit within a first time period corresponding to the last-stage LED driver circuit, the last-stage LED driver circuit can receive the first data for the last-stage LED driver circuit, be in a state of waiting for an enable (e.g., OE) instruction, and output preset data to the control circuit. The last-stage LED driver circuit can recognize the enable instruction in the first data for the last-stage LED driver circuit. While the previous-stage LED driver circuit sends second data (e.g., CT) for the last-stage LED driver circuit to the last-stage LED driver circuit within a second time period corresponding to the last-stage LED driver circuit, the last-stage LED driver circuit can receive the second data for the last-stage LED driver circuit, be in a read mode, and send the data to be read stored in the last-stage LED driver circuit to the control circuit.

[0165] Furthermore, for each stage of the multi-stage LED driver circuit other than the first stage of the LED driver circuit, data received from the previous stage of the LED driver circuit is transmitted to its downstream circuit during one or more preset time periods prior to the first time period corresponding to the LED driver circuit of the stage. For example, for each stage of the multi-stage LED driver circuit other than the first stage of the LED driver circuit, preset data is received from the previous stage of the LED driver circuit during a first time period included in the one or more preset time periods prior to the first time period corresponding to the LED driver circuit of the stage, and the preset data is transmitted to the downstream circuit; and data to be read from the previous stage of the LED driver circuit is received from the previous stage of the LED driver circuit during a second time period included in the one or more preset time periods, and the data to be read from the previous stage of the LED driver circuit is transmitted to the downstream circuit.

[0166] Furthermore, the control circuit can be further configured to send specific data to the first-stage LED driver circuit in the multi-stage LED driver circuit after the control circuit sends a global signal and a first signal specific to each stage of the LED driver circuit to the first-stage LED driver circuit. As described above, after outputting the data to be read, each stage of the LED driver circuit is in a bypass state. Therefore, each stage of the LED driver circuit can transmit the specific data to its downstream circuit. Specifically, each stage of the LED driver circuit, except for the last stage, can transmit the specific data to the next-stage LED driver circuit; the last stage of the LED driver circuit can then feed the specific data back to the control circuit.

[0167] Furthermore, the control circuit can be configured to instruct the LED driver circuits of each stage to terminate a determined operating mode. For example, the control circuit can change the level of a synchronization signal it sends to the LED driver circuits of each stage (e.g., from a high level to a low level, or from a low level to a high level). Accordingly, the LED driver circuits of each stage can terminate their current operating mode upon detecting the change in the level of the synchronization signal.

[0168] In the power saving mode, according to a first example of the present disclosure, the LED driver circuit can passively enter the power saving mode, for example, by following an instruction from a control circuit. Furthermore, according to a second example of the present disclosure, the LED driver circuit can actively enter the power saving mode, for example, by determining whether to enter the power saving mode by determining whether the duration of a period during which it receives specific data from its upstream circuit is greater than a preset threshold.

[0169] In a first example, the control circuit may be configured to send another global signal to a first-stage LED driver circuit in a multi-stage LED driver circuit, wherein the another global signal includes an instruction for instructing each stage of the LED driver circuit to adopt another operating mode. Each stage of the LED driver circuit may be configured to determine another operating mode based on the another global signal. Each stage of the LED driver circuit may also be configured to operate according to the other operating mode. Each stage of the LED driver circuit, except for the last stage of the LED driver circuit, may be configured to send the another global signal to the LED driver circuit in the next stage.

[0170] While the upstream circuit is transmitting CT, another global signal, to the LED driver circuit, the LED driver circuit can be in a waiting state for CT and in a bypass state. Furthermore, while the upstream circuit is transmitting CS and SV CMD, another global signal, to the LED driver circuit, the LED driver circuit can write SV CMD and be in a bypass state. The final-stage LED driver circuit can feed back the received global signal to the control circuit.

[0171] In other words, while the control circuit transmits CT from another global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the control circuit transmits CS and SV CMD from another global signal to the first-stage LED driver circuit, the first-stage LED driver circuit can write SV CMD and be in a bypass state. Furthermore, while the upper-stage LED driver circuit transmits CT from another global signal to its lower-stage LED driver circuit, the lower-stage LED driver circuit can be in a waiting state for CT and in a bypass state. While the upper-stage LED driver circuit transmits CS and SV CMD from another global signal to its lower-stage LED driver circuit, the lower-stage LED driver circuit can write SV CMD and be in a bypass state.

[0172] In this example, each stage of the multi-stage LED driver circuit can at least disable its data transmission function. Alternatively, each stage of the multi-stage LED driver circuit can transmit preset data to its downstream circuit. For the last stage of the LED driver circuit, its downstream circuit is the control circuit; for each stage of the LED driver circuit other than the last stage, its downstream circuit is the next stage of the LED driver circuit. The preset data described here can be data with a preset value, such as 0, because transmitting data 0 to the next stage of the LED driver circuit is more power-efficient than transmitting data 1.

[0173] In this situation, since the first-stage LED driver circuit has already received the power-saving instruction from the control circuit and entered power-saving mode, even if the control circuit sends a CT to it, the first-stage LED driver circuit can output 0 to the next-stage LED driver circuit. In other words, the first-stage LED driver circuit performs power-saving data transmission. In addition, each stage of LED driver circuit other than the first-stage LED driver circuit has also received the power-saving instruction from the control circuit and entered power-saving mode. Therefore, it can output 0 to the next-stage LED driver circuit. In other words, each stage of LED driver circuit other than the first-stage LED driver circuit performs power-saving data transmission. Furthermore, further, it is also possible to appropriately shut down part of the transmitter circuit of each stage of LED driver circuit (making it inoperative) to achieve a better power-saving effect.

[0174] Furthermore, in the second example, each LED driver circuit stage can determine whether the length of the time period during which it receives specific data from its upstream circuit is greater than a preset threshold. When the length of the time period during which the LED driver circuit stage receives specific data from its upstream circuit is greater than the preset threshold, the LED driver circuit stage changes its determined operating mode to a power-saving mode. When the length of the time period during which the LED driver circuit stage receives specific data from its upstream circuit is less than the preset threshold, the LED driver circuit stage does not change its determined operating mode to a power-saving mode. For the first-stage LED driver circuit, its upstream circuit is the control circuit; for each stage of LED driver circuit other than the first-stage LED driver circuit, its upstream circuit is the LED driver circuit stage immediately above it.

[0175] Furthermore, in this example, each LED driving circuit may start a timer upon detecting specific data, and the timer duration is a preset threshold. After the preset threshold time period expires, if the LED driving circuit still detects the specific data, the LED driving circuit may change the current operating mode to the power saving mode.

[0176] In addition, in this example, the control circuit can also instruct the LED driver circuits at each level to end the power saving mode. For example, the control circuit can change the level of the synchronization signal it sends to the LED driver circuits at each level (for example, from a high level to a low level, or from a low level to a high level). Accordingly, the LED driver circuits at each level can end the power saving mode after detecting the change in the level of the synchronization signal. After ending the power saving mode, the display driver system can prepare for the next write / read operation.

[0177] After the power saving mode ends, the display driving system can prepare for the next write / read operation.

[0178] In the power-on protection mode, the control circuit may be configured to change the level of the synchronization signal it sends to each level of the LED driver circuits according to a preset period. For example, the control circuit may change the level of the synchronization signal it sends to each level of the LED driver circuits from a high level to a low level according to a preset period, or the control circuit may change the level of the synchronization signal it sends to each level of the LED driver circuits from a low level to a high level according to a preset period.

[0179] In addition, the control circuit can be configured to send first preset data to the first-level LED driving circuit after it is turned on and before sending a global signal and a first signal for each level of LED driving circuit to the first-level LED driving circuit in the multi-level LED driving circuit.

[0180] In addition, for each level of the LED driving circuit in the multi-level LED driving circuit, it can be configured to send the second preset data to its downstream circuit when the first preset data is not received or when the first preset data is received but the level of the synchronization signal does not change a preset number of times (for example, 2 times); and send the first preset data to its downstream circuit when the first preset data is received and the level of the synchronization signal changes a preset number of times.

[0181] In addition, the control circuit can be configured to start sending the global signal and the first signal for each level of LED driving circuit to the first level of LED driving circuit in the multi-level LED driving circuit in response to the control circuit receiving the first preset data from the last level of LED driving circuit to perform write / read operations.

[0182] In the above manner, until the control circuit receives the first preset data fed back by the last-stage LED driving circuit, the control circuit and the LED driving circuits at all stages enter the normal state together to perform the write / read operation.

[0183] Through the display drive system of the above embodiment, through a specific signal transmission protocol, each light-emitting diode drive circuit can identify the data that the control circuit wants to send to itself, so that no additional pins or chip select signals are required to determine the corresponding light-emitting diode drive circuit, avoiding the use of SPI and thus avoiding certain defects caused by SPI. In addition, a power-saving mode is set for the display drive system, and the power-saving mode can save power and effectively reduce the power consumption of the chip. In addition, a power-on protection mode is set for the display drive system, and the power-on protection mode can greatly improve the ESD tolerance of the chip, thereby extending the life of the chip. In addition, by transmitting the data signal and the clock signal in a differential manner, the data signal and the clock signal can be transmitted with a smaller voltage swing (about hundreds of mV), thereby effectively suppressing the influence of noise and improving the signal transmission speed. In addition, transmitting the clock signal in series can improve the distortion of the clock signal.

[0184] Although the present invention has been disclosed above with reference to the embodiments, they are not intended to limit the present invention. Anyone with ordinary skill in the art may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for a display driving system, wherein the display driving system comprises a control circuit and a cascade-connected multi-stage light emitting diode driving circuit, the method comprising: The control circuit sends a global signal and a first signal for each stage of the LED driving circuit to a first stage of the multi-stage LED driving circuit, wherein the global signal includes an instruction for indicating an operation mode of each stage of the LED driving circuit; Each level of the light emitting diode driving circuit determines an operation mode corresponding to the instruction according to the global signal, identifies the first signal corresponding to the light emitting diode driving circuit of the level, and operates according to the determined operation mode and the corresponding first signal; as well as Each stage of the LED driver circuit, except for the last stage, sends the global signal to the next stage of the LED driver circuit, and in response to the completion of the operation according to the determined operation mode and the corresponding first signal, sends the first signal for each stage of the LED driver circuit after the last stage of the LED driver circuit to the next stage of the LED driver circuit. Wherein, the instruction is a write instruction, and the operation mode corresponding to the instruction is a write mode; or the instruction is a read instruction, and the operation mode corresponding to the instruction is a read mode, In the case where the instruction is a write instruction, the first signal for each stage of the light emitting diode driving circuit includes at least data to be written for the light emitting diode driving circuit of that stage, and wherein, for each stage of the multi-stage light emitting diode driving circuit, operating according to the determined operation mode and the corresponding first signal includes: When no data to be written for the light emitting diode driving circuit of this stage is received, sending preset data to its downstream circuit; When receiving the data to be written for the light emitting diode driving circuit of this stage, writing the data to be written for the light emitting diode driving circuit of this stage, and sending the preset data to the downstream circuit; Among them, for the last-stage LED driving circuit in the multi-stage LED driving circuit, its downstream circuit is the control circuit; for each stage LED driving circuit in the multi-stage LED driving circuit except the last-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit.

2. The method according to claim 1, wherein In the case that the instruction is a read instruction, the first signal for each stage of the light emitting diode driving circuit includes first data and second data for the light emitting diode driving circuit of this stage, wherein the first data includes an enable instruction.

3. The method according to claim 2, wherein the control circuit sending the first signal for each stage of the LED driving circuit to the first stage of the LED driving circuit in the multi-stage LED driving circuit comprises: The control circuit sends a first signal for the i-th level light emitting diode driving circuit in a preset time period corresponding to the i-th level light emitting diode driving circuit, wherein the preset time period includes a first time period and a second time period, and the control circuit sends first data for the i-th level light emitting diode driving circuit in the first time period and sends second data for the i-th level light emitting diode driving circuit in the second time period. The multi-stage light emitting diode driving circuit is an N-stage light emitting diode driving circuit, N is an integer greater than or equal to 3, and i is an integer greater than or equal to 1 and less than or equal to N.

4. The method according to claim 3, wherein: For each stage of the multi-stage light emitting diode driving circuit, operating according to the determined operation mode and the corresponding first signal includes: receiving first data for the light emitting diode driving circuit in a first time period corresponding to the light emitting diode driving circuit of the stage, and sending preset data to its downstream circuit; Identifying an enable instruction in the first data for the light emitting diode driving circuit of this stage; receiving second data for the light emitting diode driving circuit of this stage within a second time period corresponding to the light emitting diode driving circuit of this stage, and sending the data to be read stored in the light emitting diode driving circuit of this stage to its downstream circuit in response to the enable instruction, Among them, for the last-stage LED driving circuit, its downstream circuit is the control circuit; for each stage of LED driving circuit except the last-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit.

5. The method of claim 4, further comprising: For each stage of the multi-stage LED driving circuit except the first stage of the LED driving circuit, sending data received from the previous stage of the LED driving circuit to its downstream circuit in one or more preset time periods before the first time period corresponding to the LED driving circuit of the stage, including: receiving preset data from the previous-stage LED driving circuit in a first time period included in one or more preset time periods before a first time period corresponding to the LED driving circuit of the current stage, and sending the preset data to the downstream circuit; In a second time period included in the one or more preset time periods, the data to be read from the previous-level LED driving circuit is received from the previous-level LED driving circuit, and the data to be read from the previous-level LED driving circuit is sent to the downstream circuit.

6. The method of claim 1 , further comprising: The control circuit sends another global signal to the first-stage LED driving circuit in the multi-stage LED driving circuit, wherein the another global signal includes an instruction for indicating another operation mode of each stage of the LED driving circuit; Each stage of the light emitting diode driving circuit determines the another operation mode according to the another global signal; Each stage of the light emitting diode driving circuit operates according to the another operation mode; and Each stage of the LED driving circuit except the last stage of the LED driving circuit sends the other global signal to the LED driving circuit of the next stage.

7. The method of claim 6, wherein The instruction for instructing each stage of the light emitting diode driving circuit to operate in another operation mode is a power saving instruction, and the another operation mode is a power saving mode.

8. The method according to claim 7, wherein for each stage of the multi-stage LED driving circuit, operating according to the other operation mode comprises: The light emitting diode driving circuit of this level at least disables the data sending function; or The LED driver circuit at this level sends preset data to its downstream circuit. Among them, for the last-stage LED driving circuit, its downstream circuit is the control circuit; for each stage of LED driving circuit except the last-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit.

9. The method according to claim 1, further comprising: for each stage of the multi-stage LED driving circuit; The light emitting diode driving circuit of this stage determines whether the length of the time period during which it receives specific data from its upstream circuit is greater than a preset threshold; When the length of the time period during which the LED driving circuit of this stage receives specific data from the upstream circuit thereof is greater than a preset threshold, the LED driving circuit of this stage changes the determined operation mode to a power saving mode. Among them, for the first-stage LED driving circuit, its upstream circuit is the control circuit; for each stage of LED driving circuit except the first-stage LED driving circuit, its upstream circuit is the previous stage LED driving circuit.

10. The method of claim 1, further comprising: The control circuit changes the level of the synchronization signal sent to the light emitting diode drive circuits of each level according to a preset period; The control circuit sends first preset data to a first-stage LED driving circuit in the multi-stage LED driving circuit after the control circuit is powered on and before sending the global signal and the first signal for each stage of the LED driving circuit to the first-stage LED driving circuit; For each stage of the multi-stage LED driving circuit, the following operations are performed: if the first preset data is not received or if the first preset data is received but the level of the synchronization signal does not change for a preset number of times, the second preset data is sent to the downstream circuit; if the first preset data is received and the level of the synchronization signal changes for a preset number of times, the first preset data is sent to the downstream circuit; wherein, for the last stage of the LED driving circuit in the multi-stage LED driving circuit, the downstream circuit is the control circuit, and for each stage of the LED driving circuit in the multi-stage LED driving circuit except the last stage, the downstream circuit is the LED driving circuit of the next stage; In response to the control circuit receiving the first preset data from the last stage LED driving circuit, the control circuit starts to send the global signal and the first signal for each stage LED driving circuit to the first stage LED driving circuit in the multi-stage LED driving circuit.

11. The method of claim 1, wherein Each stage of the light-emitting diode driving circuit is used to drive a display that uses micro light-emitting diodes (Micro LEDs) as display pixels.

12. A display driving system comprising: control circuit and cascade-connected multi-stage light-emitting diode drive circuit, wherein the control circuit is configured to send a global signal and a first signal for each stage of the LED driving circuit to a first stage of the multi-stage LED driving circuit, wherein the global signal includes an instruction for indicating an operation mode of each stage of the LED driving circuit; Each stage of the light emitting diode driving circuit is configured to determine an operation mode corresponding to the instruction according to the global signal, identify a first signal corresponding to the light emitting diode driving circuit of the stage, and operate according to the determined operation mode and the corresponding first signal; and Each stage of the LED driver circuit, except for the last stage of the LED driver circuit, is further configured to send the global signal to the LED driver circuit of the next stage thereof, and in response to completion of the operation according to the determined operation mode and the corresponding first signal, send the first signal for each stage of the LED driver circuits subsequent to the LED driver circuit of the next stage thereof to the LED driver circuit of the next stage thereof. The instruction is a write instruction, and the operation mode corresponding to the instruction is a write mode; or the instruction is a read instruction, and the operation mode corresponding to the instruction is a read mode, Wherein, when the instruction is a write instruction, the first signal for each level of LED driving circuit includes at least the data to be written for the LED driving circuit of this level, and each level of LED driving circuit in the multi-level LED driving circuit is configured to send preset data to its downstream circuit when the data to be written for the LED driving circuit of this level is not received; and write the data to be written for the LED driving circuit of this level when the data to be written for the LED driving circuit of this level is received, and send the preset data to the downstream circuit; wherein, for the last level of LED driving circuit in the multi-level LED driving circuit, its downstream circuit is the control circuit; for each level of LED driving circuit except the last level of LED driving circuit in the multi-level LED driving circuit, its downstream circuit is the LED driving circuit of the next level.

13. The display driving system according to claim 12, wherein In the case that the instruction is a read instruction, the first signal for each stage of the light emitting diode driving circuit includes first data and second data for the light emitting diode driving circuit of this stage, wherein the first data includes an enable instruction.

14. The display driving system according to claim 13, wherein The control circuit is configured to send a first signal for the i-th level light emitting diode driving circuit in a preset time period corresponding to the i-th level light emitting diode driving circuit, wherein the preset time period includes a first time period and a second time period, and the control circuit sends first data for the i-th level light emitting diode driving circuit in the first time period and sends second data for the i-th level light emitting diode driving circuit in the second time period, wherein, The multi-stage light emitting diode driving circuit is an N-stage light emitting diode driving circuit, N is an integer greater than or equal to 3, and i is an integer greater than or equal to 1 and less than or equal to N.

15. The display driving system according to claim 14, wherein Each stage of the multi-stage LED driving circuit is configured to receive first data for the LED driving circuit in a first time period corresponding to the LED driving circuit of the stage, and send preset data to its downstream circuit; identify an enable instruction in the first data for the LED driving circuit of the stage; receive second data for the LED driving circuit of the stage in a second time period corresponding to the LED driving circuit of the stage, and send the data to be read stored in the LED driving circuit of the stage to its downstream circuit in response to the enable instruction, wherein For the last-stage LED driving circuit, its downstream circuit is the control circuit; for each stage of LED driving circuit except the last-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit.

16. The display driving system according to claim 15, wherein Each level of LED driving circuit in the multi-level LED driving circuit except the first level LED driving circuit is configured to receive preset data from its previous level LED driving circuit in a first time period included in one or more preset time periods before the first time period corresponding to the LED driving circuit of this level, and send the preset data to the downstream circuit; and receive data to be read from the previous level LED driving circuit in a second time period included in the one or more preset time periods, and send data to be read from the previous level LED driving circuit to the downstream circuit.

17. The display driving system according to claim 12, wherein The control circuit is configured to send another global signal to a first-stage LED driving circuit in the multi-stage LED driving circuit, wherein the another global signal includes an instruction for indicating another operation mode of each stage of the LED driving circuit; Each stage of the light emitting diode driving circuit is configured to determine the another operation mode according to the another global signal; Each stage of the light emitting diode driving circuit is configured to operate according to the another operation mode; as well as Each stage of the LED driving circuit except the last stage of the LED driving circuit is configured to send the other global signal to the LED driving circuit of the next stage.

18. The display driving system according to claim 17, wherein The instruction for instructing each stage of the light emitting diode driving circuit to operate in another operation mode is a power saving instruction, and the another operation mode is a power saving mode.

19. The display driving system according to claim 18, wherein Each stage of the multi-stage LED driving circuit is configured to at least disable a data transmission function or transmit preset data to its downstream circuit. in, For the last-stage LED driving circuit, its downstream circuit is the control circuit; for each stage of LED driving circuit except the last-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit.

20. The display driving system according to claim 12, wherein Each stage of the multi-stage LED driving circuit is further configured to determine whether the length of a time period during which it receives specific data from its upstream circuit is greater than a preset threshold; When the length of the time period during which the LED driving circuit of this stage receives specific data from the upstream circuit thereof is greater than a preset threshold, the LED driving circuit of this stage changes the determined operation mode to a power saving mode. in, For the first-stage LED driving circuit, its upstream circuit is the control circuit; for each stage of LED driving circuit except the first-stage LED driving circuit, its upstream circuit is the previous stage LED driving circuit.

21. The display driving system according to claim 12, wherein The control circuit is configured to change the level of the synchronization signal sent to the light emitting diode driving circuits of each level according to a preset period; The control circuit is configured to send first preset data to a first-stage LED driving circuit in the multi-stage LED driving circuit after the control circuit is powered on and before sending the global signal and the first signal for each stage of the LED driving circuit to the first-stage LED driving circuit; Each stage of the multi-stage LED driving circuit is configured to perform the following operations: if the first preset data is not received or if the first preset data is received but the level of the synchronization signal does not change for a preset number of times, the second preset data is sent to the downstream circuit; if the first preset data is received and the level of the synchronization signal changes for a preset number of times, the first preset data is sent to the downstream circuit; wherein, For the last-stage LED driving circuit in the multi-stage LED driving circuit, its downstream circuit is the control circuit; for each stage of the LED driving circuit in the multi-stage LED driving circuit except the last-stage LED driving circuit, its downstream circuit is the next-stage LED driving circuit; In response to the control circuit receiving the first preset data from the last level of LED driving circuit, the control circuit is configured to start sending the global signal and the first signal for each level of LED driving circuit to the first level of LED driving circuit in the multi-level LED driving circuit.

22. The display driving system according to claim 12, wherein Each stage of the light-emitting diode driving circuit is used to drive a display that uses micro light-emitting diodes (Micro LEDs) as display pixels.

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