Bus control method and apparatus for LED substrate, and LED display system

Abstract

Disclosed are a bus control method and apparatus for an LED substrate, and an LED display system. The method comprises: acquiring fault information of an LED substrate; determining the coordinates of all faulty LED lamps and fault starting coordinates among the coordinates of all the faulty LED lamps; using, as a target drive circuit, an LED drive circuit of an LED lamp corresponding to the fault starting coordinates; controlling a switch circuit to be turned on, which switch circuit corresponds to an input end of the target drive circuit, wherein the other end of the switch circuit is connected to an output end of an LED drive circuit longitudinally corresponding to the target drive circuit in the LED substrate; and on the basis of the number of columns of a matrix of the LED substrate, updating preset addresses in LED drive circuits corresponding to the faulty LED lamps, wherein the preset addresses are used by the LED drive circuits to read drive data from received bus data or output data, and control, on the basis of the drive data, the corresponding LED lamps to display.

Description

Bus control method and device of LED substrate and LED display system TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of LED (Light Emitting Diode), and particularly relates to a bus control method and device of LED substrate and an LED display system. BACKGROUND

[0002] In an LED panel, the driving circuits of each LED lamp bead are connected in series with each other. When a fault occurs in any one driving circuit, all the LED lamp beads connected with the driving circuits behind the fault driving circuit will be extinguished, thereby affecting the display of the entire LED panel. Therefore, the driving circuits of each LED lamp are usually connected in parallel, so that each LED unit works independently, and even if a fault occurs in a certain LED lamp, it will not affect other lamp beads. However, although this parallel connection scheme can avoid large-area failure caused by a single lamp bead, in the case of parallel connection, once a short circuit problem occurs in the bus to which the LED lamps are connected in parallel, all the lamp beads behind the breakpoint will be affected. SUMMARY

[0003] The present disclosure provides a bus control method and device of LED substrate and an LED display system, which can avoid the problem that a large area of LED lamps do not display when a fault occurs in the bus, and improve the reliability of the LED lamps.

[0004] In a first aspect, the present disclosure provides a bus control method of LED substrate, applied to a master control chip; a plurality of LED driving circuits in the LED substrate are connected in parallel on an output bus of the master control chip; the method comprises: obtaining fault information of the LED substrate; determining coordinates of all faulty LED lamps and a fault starting coordinate among them; taking the LED driving circuit of the LED lamp corresponding to the fault starting coordinate as a target driving circuit; controlling a switch circuit corresponding to an input end of the target driving circuit to be connected; wherein the other end of the switch circuit is connected to the output end of the LED driving circuit corresponding to the target driving circuit in the LED substrate; updating a preset address in the LED driving circuit corresponding to each LED lamp based on the matrix number of the LED substrate; wherein the preset address is used for the LED driving circuit to read driving data in the received bus data or output data, and control the corresponding LED lamp to display based on the driving data.

[0005] Further, the method further comprises: sending a feedback request instruction to each LED driving circuit at a preset period; the feedback request instruction is used to make the LED driving circuit send pre-stored coordinate data; determining whether the number of received coordinate data is equal to the product of the row and column numbers of the LED substrate; if not equal, generating fault information.

[0006] Further, the method further comprises: acquiring a brightness image of the LED substrate when powered on; binarizing the brightness image by using a Roberts algorithm to obtain a binary image; determining whether there is a black pixel point in the range corresponding to the LED substrate in the binary image; if there is, generating fault information.

[0007] Further, the above-mentioned determination of the coordinates of all faulty LED lamps and the fault starting coordinates therein comprises: comparing the coordinate data and the matrix of the LED substrate to obtain the coordinates of each faulty LED lamp; and taking the coordinate with the smallest column number in each coordinate as the fault starting coordinate.

[0008] Further, the above-mentioned determination of the coordinates of all faulty LED lamps and the fault starting coordinates therein comprises: generating a target grid based on the row and column numbers of the LED substrate and the size of the LED substrate in the binary image; aligning the target grid and the binary image to obtain the coordinates of each black pixel point; and taking the coordinate with the smallest column number in each coordinate as the fault starting coordinate.

[0009] Further, the above-mentioned updating of the preset address in the LED driving circuit corresponding to each faulty LED lamp based on the matrix column number comprises: calculating the difference between the column number of the coordinate and the column number of the fault starting coordinate; adding the difference and the matrix column number to obtain an updated preset address; generating an addressing instruction based on the updated preset address and the coordinate, and sending it to the LED driving circuit corresponding to the coordinate, so that the preset address therein is replaced by the updated preset address.

[0010] Further, the method further comprises: after the control switch circuit is connected, acquiring the fault information of the LED substrate again; determining the coordinates of all faulty LED lamps; and generating a lamp bead fault prompt information based on each coordinate.

[0011] Further, the method further comprises: acquiring the usage time length of the LED driving circuit, and calculating a light compensation value based on the usage time length; and putting the light compensation value into the driving data corresponding to the LED driving circuit.

[0012] In a second aspect, the present disclosure provides a bus control device of an LED substrate, applied to a master chip; a plurality of LED driving circuits in the LED substrate are connected in parallel to an output bus of the master chip; the device comprises: an acquisition module configured to acquire fault information of the LED substrate; a determination module configured to determine coordinates of all faulty LED lamps and a fault starting coordinate among the faulty LED lamps; a target module configured to take an LED driving circuit of an LED lamp corresponding to the fault starting coordinate as a target driving circuit; a control module configured to control a switch circuit corresponding to an input end of the target driving circuit to be connected; wherein the other end of the switch circuit is connected to an output end of an LED driving circuit longitudinally corresponding to the target driving circuit in the LED substrate; and an update module configured to update a preset address in the LED driving circuit corresponding to each of the faulty LED lamps based on a matrix number of the LED substrate; wherein the preset address is used by the LED driving circuit to read driving data in received bus data or output data, and control the corresponding LED lamp to display based on the driving data.

[0013] In a third aspect, the present disclosure provides an LED display system, comprising a master chip and an LED substrate; the LED substrate comprises a plurality of LED devices arranged in a matrix form, each LED device comprising an LED driving circuit and an LED lamp connected to an output end of the LED driving circuit; the master chip comprises a plurality of output ports, each output port being connected to a corresponding output bus; input ends of LED driving circuits in the same row of the matrix are connected in parallel to one output bus, and are also connected to output ends of longitudinally corresponding LED driving circuits in the matrix through a switch circuit; the master chip is configured to locate a fault starting coordinate among faulty LED lamps when acquiring fault information; and control a switch circuit corresponding to an input end of an LED driving circuit corresponding to the fault starting coordinate to be connected; and update a preset address in the LED driving circuit corresponding to each of the faulty LED lamps based on a matrix number of the LED substrate; wherein the preset address is used by the LED driving circuit to read driving data in received bus data or output data, and control the corresponding LED lamp to display based on the driving data.

[0014] Further, the LED driving circuit comprises a data shaping module, an addressing control module, a photosensitive extraction module and a driving module; the data shaping module is configured to receive bus data or output data, filter the bus data or the output data to obtain serial data, and send the serial data to the addressing control module; the addressing control module is configured to read driving data in the serial data according to a preset address, intercept serial data after the preset address as output data, send the driving data and the output data to the data shaping module, and receive an updated preset address from the photosensitive extraction module and replace the preset address; the data shaping module is further configured to send the driving data to the driving module to control the LED lamp to display according to the driving data, and send an addressing instruction to the photosensitive extraction module when the driving data comprises the addressing instruction; send the output data to an output end; and the photosensitive extraction module is configured to receive a light signal after receiving the addressing instruction, convert the light signal to obtain the updated preset address, and send the updated preset address to the addressing control module.

[0015] Further, the data shaping module is configured to filter out pulses with a frequency greater than 33 MHz in the bus data or the output data.

[0016] Further, the driving module is configured to generate a driving current according to the driving data and send the driving current to a corresponding LED lamp; the driving current ranges from 0.3 mA to 25 mA.

[0017] Further, the addressing control module comprises an address storage unit configured to store the preset address; the address storage unit has a maximum storage bit number of 12 bits.

[0018] Further, the driving circuit further comprises a clock module; the clock module is configured to generate a clock signal with a frequency of 8 MHz and send the clock signal to the data shaping module, the addressing control module and the driving module respectively.

[0019] Further, the driving circuit further comprises a voltage stabilizing module; the voltage stabilizing module is configured to stabilize a power supply voltage to 5 V and supply the data shaping module, the addressing control module, the driving module and the photosensitive extraction module with the stabilized power supply voltage respectively.

[0020] Further, the bus data has a frequency ranging from 800 kHz to 1.2 MHz.

[0021] Further, each output port of the master control chip is provided with a pull-down resistor; the pull-down resistor has an impedance value ranging from 15 KΩ to 20 KΩ.

[0022] Further, on the LED substrate, each LED driving circuit in the first row is connected in parallel to two output buses.

[0023] Further, the LED substrate has a maximum matrix row number of 64 and a maximum matrix column number of 600.

[0024] The bus control method of the LED substrate provided by the embodiment of the present disclosure can locate the fault starting point in each faulty LED lamp after obtaining the fault information of the LED substrate, and connect the switch circuit between the target driving circuit corresponding to the fault starting point and the output end of the LED driving circuit corresponding to the matrix longitudinal direction of the LED substrate, that is, the output end of the same column of LED driving circuit is used as the standby input, which is started when the bus fails. At the same time, considering that the output data of the LED driving circuit is different from the bus data transmitted on the bus, the preset address in each LED driving circuit connected in parallel after updating the fault point is updated based on the matrix column number, so that the correct driving data can still be read for display. The above method can avoid the problem that a large area of LED lamps do not display when any bus in the LED substrate fails, and improves the reliability of the LED lamp. BRIEF DESCRIPTION OF DRAWINGS

[0025] FIG. 1 is a flowchart of a bus control method of an LED substrate provided by an exemplary embodiment of the present disclosure.

[0026] FIG. 2 is a structure diagram of an LED display system provided by an exemplary embodiment of the present disclosure.

[0027] FIG. 3 is a structure diagram of a bus control device of an LED substrate provided by an exemplary embodiment of the present disclosure.

[0028] FIG. 4 is a frame structure diagram of bus data provided by an exemplary embodiment of the present disclosure.

[0029] FIG. 5 is a sampling timing diagram of zero-return code bus data provided by an exemplary embodiment of the present disclosure.

[0030] FIG. 6 is a data form diagram of 8-bit zero-return code bus data provided by an exemplary embodiment of the present disclosure.

[0031] FIG. 7 is a sampling timing diagram of driving data and output data provided by an exemplary embodiment of the present disclosure.

[0032] FIG. 8 is a structure diagram of an LED driving circuit provided by an exemplary embodiment of the present disclosure.

[0033] FIG. 9 is a structure diagram of a clock module provided by an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. The described embodiments are only part of the embodiments of the present disclosure, not all the embodiments.

[0035] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative labor fall within the scope of protection of the present disclosure.

[0036] Referring to FIG. 1 and FIG. 2, the present disclosure provides a bus control method of an LED substrate, applied to a master chip; a plurality of LED driving circuits in the LED substrate are connected in parallel to an output bus of the master chip; the method specifically comprises steps S1 to S5.

[0037] In step S1, fault information of the LED substrate is acquired.

[0038] In the embodiments of the present disclosure, the fault information can be provided by a cloud platform, through which the current of each LED lamp in the LED substrate can be acquired and detected, and when the current of an LED lamp is lower than a preset threshold, the fault information is generated and input to the master chip.

[0039] In step S2, coordinates of all faulty LED lamps and a fault starting coordinate among them are determined.

[0040] In the embodiments of the present disclosure, the coordinates are the positions of the faulty LED lamps in the LED substrate matrix, i.e. the row and column numbers, and the fault starting coordinate is the position of the first LED lamp among all the faulty LED lamps, i.e. the LED lamp with the smallest row and column numbers. When the cloud platform generates the fault information, the coordinates of the LED lamps with unqualified current are put into the fault information, facilitating the determination of the fault starting point.

[0041] In step S3, the LED driving circuit corresponding to the LED lamp with the fault starting coordinate is taken as a target driving circuit.

[0042] In the embodiments of the present disclosure, since the LED lamp and the LED driving circuit correspond to each other one by one, they share one coordinate to represent their positions.

[0043] In step S4, a switch circuit corresponding to the input end of the target driving circuit is connected; and the other end of the switch circuit is connected to the output end of the LED driving circuit longitudinally corresponding to the target driving circuit in the LED substrate.

[0044] In step S5, the preset addresses in the LED driving circuits corresponding to the faulty LED lamps are updated based on the matrix column number; the preset addresses are used by the LED driving circuits to read driving data from the received bus data or output data and control the corresponding LED lamps to display based on the driving data. Specifically, before the fault occurs, each LED driving circuit receives bus data. After the communication switch circuit is connected, each LED driving circuit after the fault starting point receives output data of the LED driving circuit in the same column as the target driving circuit. Since the output data is not equal to the bus data but only a part of the bus data, the preset addresses need to be updated.

[0045] The bus control method for the LED substrate provided in the above embodiment can locate the fault starting point in each faulty LED lamp after obtaining the fault information of the LED substrate, connect the switch circuit between the output end of the target driving circuit corresponding to the fault starting point and the LED driving circuit corresponding to the matrix longitudinal direction of the LED substrate, that is, use the output end of the LED driving circuit in the same column as the backup input, and start when the bus is faulty. Meanwhile, considering that the output data of the LED driving circuit is different from the bus data transmitted on the bus, the preset addresses in each LED driving circuit connected in parallel after the fault point are updated based on the matrix column number, so that the correct driving data can still be read for display. The above method can avoid the problem that a large area of LED lamps do not display when any bus in the LED substrate fails, and improves the reliability of the LED lamps.

[0046] Further, the method further includes steps S011 to S013.

[0047] In step S011, a feedback request instruction is sent to each LED driving circuit at a preset period.

[0048] In the embodiment of the present disclosure, the feedback request instruction is used to make the LED driving circuit send the pre-stored coordinate data.

[0049] The coordinate data and the above-mentioned coordinate content are the same, that is, the position of each LED driving circuit in the substrate; for example, the coordinate data of the LED driving circuit in the 32nd row and the 64th column of the LED substrate is (32, 64), which only needs to be converted and sent as a signal.

[0050] In step S012, it is judged whether the number of received coordinate data is equal to the product of the row and column numbers of the LED substrate.

[0051] Specifically, assuming that the LED substrate is 64 rows and 64 columns, there should be 4096 coordinate data. If the received coordinate data is less than 4096, it means that there is an LED lamp that is not working, that is, the circuit has failed.

[0052] In step S013, if not equal, a fault information is generated.

[0053] The step S2 of determining the coordinates of all the faulty LED lamps and the faulty starting coordinates includes the following steps S211 and S212.

[0054] In step S211, the coordinates of each LED lamp are obtained by comparing the coordinate data and the matrix of the LED substrate.

[0055] In step S212, the coordinate with the smallest number of columns is taken as the faulty starting coordinate.

[0056] In the specific implementation process, there may be a situation where multiple output buses are disconnected at the same time, so before step S212, the coordinates can be classified according to the number of rows in each coordinate, and the coordinates belonging to the same row are taken as a group, and the subsequent steps S212 and steps S3-S5 are executed in turn.

[0057] In some embodiments, the method further includes steps S021 to S024.

[0058] In step S021, the brightness image of the LED substrate when powered on is obtained.

[0059] In step S022, the Roberts algorithm is used to binarize the brightness image to obtain a binary image.

[0060] In step S023, it is determined whether the range corresponding to the LED substrate in the binary image has black pixel points.

[0061] In step S024, if there are, a fault information is generated.

[0062] The step S2 of determining the coordinates of all the faulty LED lamps and the faulty starting coordinates includes the following steps S221 to S223.

[0063] In step S221, a target grid is generated based on the number of rows and columns of the LED substrate and the size of the LED substrate in the binary image.

[0064] In step S222, the target grid and the binary image are aligned to obtain the coordinates of each black pixel point.

[0065] Specifically, the target grid and the LED substrate in the binary image have the same size, each grid corresponds to an LED lamp in the LED substrate, and the coordinates of each grid are the coordinates of the LED lamp; if there are black pixel points in the range framed by a certain grid, it means that the corresponding LED lamp has failed.

[0066] In step S223, the coordinate with the smallest column number is located as the fault starting coordinate.

[0067] Similarly, considering that there can be multiple output buses that are disconnected at the same time, the coordinates can be classified by the row number in step S223, and the coordinates belonging to the same row are taken as a group. The subsequent step S223 and steps S3-S5 are executed in sequence according to the coordinate group.

[0068] The above two embodiments respectively give two methods for locating the fault starting coordinate. The first method has high detection accuracy, but requires at least two frames of time to send and receive data. The second method does not require the occupation of the output bus, but the detection accuracy is easily affected by the threshold in the Roberts algorithm.

[0069] In some embodiments, the step S5 of updating the preset address of the LED driving circuit corresponding to the LED lamp of the fault LED based on the matrix column number can specifically include the following steps S51-S53.

[0070] In step S51, the difference between the column number of the coordinate and the column number of the fault starting coordinate is calculated.

[0071] In step S52, the difference and the matrix column number are added to obtain the updated preset address.

[0072] Specifically, assuming that the LED substrate is a 64*64 matrix, i.e., the matrix column number is 64; the LED lamps at coordinates (2, 32)-(2, 64) are detected to be faulty, i.e., the fault point is the midpoint of the output bus connected to the second row of LED driving circuits, the coordinate (2, 32) is located as the fault starting coordinate; and the input end of the LED driving circuit at coordinate (2, 32) is connected to the output end of the LED driving circuit at coordinate (1, 32) through the switching circuit, and the output data received by the LED driving circuit at coordinate (2, 32) is the bus data after removing the first 32 groups of driving data. Therefore, the preset address of the LED driving circuit corresponding to the LED lamp at the fault starting coordinate will change from 96 to 64, so that the driving data belonging to itself can continue to be read in the output data.

[0073] As can be seen, after the switching circuit is connected, the LED driving circuit at the fault starting coordinate updates the preset address to the matrix column number. The updated preset address of the LED driving circuit at coordinate (2, 33) is 64 plus 1, i.e., the difference in the column number.

[0074] In step S53, an addressing instruction is generated based on the updated preset address and the coordinate, and is sent to the LED driving circuit corresponding to the coordinate, so that the preset address is replaced by the updated preset address.

[0075] Specifically, in the case that the LED driving circuit receives the update preset address in a light-sensitive manner, the addressing instruction will be put into the mth driving data in the bus data, so that the corresponding LED driving circuit can convert the update preset address according to the displayed light signal through the light-sensitive extraction module after displaying the LED according to the driving data.

[0076] In the embodiments of the present disclosure, the value of m depends on the coordinates of the corresponding LED lamp. When the coordinates are (2, 32), it means that the LED driving circuit corresponding to the LED lamp is the 64th (2-1) + 32 = 96th driving circuit on the LED substrate, and m is 96 at this time.

[0077] The above embodiment determines the update preset address based on the difference between the column number of the coordinates and the column number of the failure starting coordinates, without manual calculation and modification, and does not cause pause or delay in the display of the LED substrate.

[0078] In some embodiments, the method further comprises: after the switch circuit is connected, acquiring the failure information of the LED substrate again; determining the coordinates of all the failed LED lamps; and generating a lamp bead failure prompt information based on each coordinate.

[0079] Specifically, if there is still LED lamp failure after connecting the switch circuit, it can be determined that the problem is not completely the breakpoint failure of the bus, and there is also a problem in the internal lamp bead that causes the LED lamp to fail to work normally.

[0080] The above embodiment determines the update preset address based on the difference between the column number of the coordinates and the column number of the failure starting coordinates, without manual calculation and modification, and does not cause pause or delay in the display of the LED substrate.

[0081] In some embodiments, the method further comprises: acquiring the usage time of the LED driving circuit, and calculating a light compensation value based on the usage time; and putting the light compensation value into the driving data corresponding to the LED driving circuit.

[0082] Specifically, the essence of the LED lamp is a light-emitting diode. The light brightness generated by the light-emitting diode in the specific application process will be affected by various factors and will decay, such as process materials, fluorescent powder, temperature, humidity, usage time, etc. The most important factor is the time. The following function is the light-emitting diode life function: Where y represents the luminous efficiency, t represents the usage time, and e represents the natural constant. Generally, the luminous efficiency is less than 0.3, and the LED life is cut off, so when the switch circuit is connected but failure information is still received, the luminous flux of the corresponding failed LED lamp can be calculated to determine whether it is less than 0.3. If so, a lamp bead replacement prompt information can be generated based on the coordinates of the corresponding LED lamp.

[0083] Compensation coefficient That is, the master control chip sends the driving data to a certain LED driving circuit through the output bus, and the driving data is sent at times. Ideally, this compensation can ensure that the corresponding LED lamp emits light stably.

[0084] Further, when the length of the generated driving data is 24 bits, the single-color gray scale of RGB in the LED lamp is 256, but when the length of the driving data is 48 bits, the single-color gray scale of RGB will reach 65536, that is, more dazzling effects are obtained by sacrificing the length of the driving data. In view of this problem, the present disclosure further provides a method that can guarantee the dazzling effect and use the 24-bit mode for data transmission: converting 24-bit driving data into 48-bit by a gamma verification algorithm, that is, outputting the display after gamma compensation of the actual output gray scale; this step can be realized by the LED driving circuit itself or by the control algorithm.

[0085] The above embodiment adds compensation in the corresponding driving data according to the use time of the LED lamp, ensures the stable display of the corresponding LED lamp, and further improves the accuracy of judging whether each LED lamp on the substrate is faulty by the image.

[0086] Please refer to FIG. 3, the embodiment of the present disclosure further provides a bus control device of an LED substrate, which is applied to a master control chip; a plurality of LED driving circuits in the LED substrate are connected in parallel to the output bus of the master control chip; the device comprises: an acquisition module 101, configured to acquire the fault information of the LED substrate; a determination module 102, configured to determine the coordinates of all faulty LED lamps and the fault starting coordinates; a target module 103, configured to take the LED driving circuit of the LED lamp corresponding to the fault starting coordinates as a target driving circuit; a control module 104, configured to control the switch circuit corresponding to the input end of the target driving circuit to be connected; wherein the other end of the switch circuit is connected to the output end of the LED driving circuit corresponding to the target driving circuit in the LED substrate; and an update module 105, configured to update the preset address in the LED driving circuit corresponding to each LED lamp based on the matrix number of the LED substrate; wherein the preset address is used for the LED driving circuit to read the driving data in the received bus data or output data, and control the corresponding LED lamp to display based on the driving data.

[0087] The specific definition of the bus control device of the LED substrate provided in this embodiment can be referred to the embodiment of the bus control method of the LED substrate, which is not described herein again. Each module in the bus control device of the LED substrate can be realized by software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory in the computer device in software form, so as to be called and executed by the processor.

[0088] Referring to FIG. 2, the embodiment of the present disclosure further provides an LED display system, which comprises a master control chip and an LED substrate.

[0089] The LED substrate comprises a plurality of LED devices arranged in a matrix form, each of which comprises an LED driving circuit and an LED lamp connected to the output end of the LED driving circuit; the master control chip comprises a plurality of output ports, each of which is connected to a corresponding output bus.

[0090] The input ends of the LED driving circuits in the same row of the matrix are connected in parallel to an output bus, and are further connected to the output ends of the longitudinally corresponding LED driving circuits in the matrix through a switching circuit. The longitudinally corresponding LED driving circuit can be the LED driving circuit in the same column of the previous row, i.e. the input end of the driving circuit with coordinates (i, j) is connected to the output end of the driving circuit with coordinates (i-1, j). The bus data sent by the output bus corresponding to each output port is the same, so that the correct driving data can be sampled when the LED driving circuit receives the output data of the LED driving circuit in the previous row.

[0091] The master control chip is configured to locate the fault starting coordinates in the faulty LED lamp when obtaining the fault information, and to control the switching circuit corresponding to the input end of the LED driving circuit corresponding to the fault starting coordinates to be connected, and to update the preset address in the LED driving circuit corresponding to each faulty LED lamp based on the number of rows of the matrix of the LED substrate.

[0092] The preset address is used by the LED driving circuit to read the driving data from the received bus data or output data, and to control the corresponding LED lamp to display based on the driving data.

[0093] The encoding mode of the bus data DIN output by the master control chip is return-to-zero code or return-to-one code.

[0094] If the bus fails, the receiving data of the LED drive circuit corresponding to the failure point will change from the bus data to the output data of the LED drive circuit in the same column of the previous row. Since the output data is the latter half of the bus data, only the length is different, and the sampling process will not change. Therefore, in the sampling process of the following driving data and output data, the bus data is described.

[0095] Please refer to FIG. 4. When the bus data is transmitted in the form of a return-to-zero code, taking the example of an LED drive circuit using 8-bit PWM (Pulse Width Modulation) to control the LED lamp, the R, G, and B PWM output ports of the LED drive circuit send signals with different duty cycles according to the received 24-bit data. If the bus data at the input end is a RESET signal, the LED drive circuit will send the received data to the display and re-receive new bus data after the RESET signal ends. Before the RESET signal is received, the original output of the R, G, and B pins remains unchanged. When a low-level RESET signal of 80 μs or more is received, the LED drive circuit outputs the 24-bit PWM data just received to the R, G, and B pins.

[0096] Please refer to FIG. 5 and FIG. 6. Since the bus data is transmitted in the form of a return-to-zero code, it is recognized in the form of rising edge trigger alignment and clock counting sampling. When the input end DIN of the LED drive circuit receives 0 / 1 data, the rising edge triggers the sampling clock enable signal SCLK_EN, which enables the internal OSC (Oscillator) to work and generate a clock signal SCLK. The clock signal SCLK counts to 3.5 clocks to sample the bus data. The 0 code is stably recognized as 0, and the 1 code is stably recognized as 1.

[0097] Please refer to FIG. 7. Assuming that the bus data received by the LED drive circuit includes 8 groups of driving data, the LED drive circuit internally designs a counter DATA_CNT to count which group of data is currently being received. If the preset address is 2, when the counter counts to 2, the address matching is successful, and the address matching signal ADDR_MATCH flag is set to 1. Then the driving data is extracted, that is, the driving data D2 is extracted during the period when the counter DATA_CNT = 2. When the count value of the counter continues to increase, the address matching signal ADDR_MATCH is released, and the DOUT output enable DOUT_EN is generated at the same time. The received bus data is intercepted from the end of the preset address to form the output data, which is sent out from the output end DOUT.

[0098] Through the above process, the LED drive circuit can extract the driving data in the bus data according to the preset address.

[0099] The LED display system provided by the above embodiment realizes normal input and display in the case of bus failure by connecting the input end of the LED drive circuit to the output end of the LED drive circuit corresponding in the vertical direction in the matrix through the switching circuit, and avoids large-area lamp bead extinction in the parallel LED substrate caused by bus failure without increasing too many buses.

[0100] Please refer to FIG. 8, the embodiment of the present disclosure further provides an LED drive circuit, comprising a data shaping module, an addressing control module, a photosensitive extraction module and a drive module.

[0101] The data shaping module is configured to receive bus data or output data, filter the bus data or output data to obtain serial data, send the serial data to the addressing control module, and receive the updated preset address from the photosensitive extraction module and replace the preset address.

[0102] The data shaping module is further configured to send the drive data to the drive module to control the LED lamp to display according to the drive data, and send the addressing instruction to the photosensitive extraction module when the drive data comprises the addressing instruction, send the output data to the output end, and the photosensitive extraction module is configured to receive the light signal after receiving the addressing instruction, convert the light signal to obtain the updated preset address, and send the updated preset address to the addressing control module.

[0103] Specifically, when the output bus connected in parallel with the LED drive circuit is not faulty, the data shaping module receives the bus data on the output bus, and when the output end of the LED drive circuit of the same column in the previous row is started as a backup input due to failure, the data shaping module receives the output data of the output end of the LED drive circuit of the same column in the previous row.

[0104] When the drive data comprises the addressing instruction, it indicates that the preset address needs to be updated, so the photosensitive extraction module is started at the same time of the drive data display to convert the received light signal to the updated preset address.

[0105] The LED drive circuit provided by the above embodiment receives the updated preset address through the photosensitive extraction module, so that the addressing control module can still read the correct drive data and display when the bus data is switched to the output data, realizes the continuous work of other drive circuits in the case of bus failure, and improves the reliability of the LED lamp display.

[0106] In some embodiments, the data shaping module is configured to filter out pulses with a frequency greater than 33MHz from the bus data or the output data.

[0107] Specifically, within the range of commonly used bus data frequencies, pulses with a frequency greater than 33MHz are generally considered to be interference signals.

[0108] In some embodiments, the driving module is configured to generate driving currents according to the driving data and send the driving currents to corresponding LED lamps; the range of the driving currents is 0.3mA-25mA. Specifically, the magnitude of the driving currents sent to the R, G, and B lamp beads in the LED lamps determines the brightness of the corresponding lamp beads, and the range of the driving currents for different LED products can be different, as shown in Table 1.

[0109] In addition, there are some fixed constant current output products, all within this range, such as 5mA, 9mA, 12mA, etc.; the current range and gear can be adjusted in design, but all within 0.3mA-25mA, and the maximum number of gears can be set to 256 gears.

[0110] In some embodiments, the addressing control module includes an address storage unit configured to store a preset address.

[0111] Specifically, the maximum storage bit number of the address storage unit is 12 bits.

[0112] Specifically, the LED driving circuit needs to preset an address in parallel application, and the bit width of the preset address determines the total number of nodes that can be connected in parallel on the parallel link, that is, determines the maximum length of the module pixel points in application. The maximum bit width of the address currently used is 12 bits. Without considering the refresh rate, a maximum of 4096 driving nodes can be connected in parallel on the DIN. After all the parallel address codes are used up, the number of nodes on the link still cannot meet the demand, and a serial-parallel mode can be used to expand the address length, that is, the output of the last LED driving circuit of the parallel link is used as the input bus of the next parallel link. For example, when the address is 12 bits, the maximum number of parallel connections is 4096, and if more than 4096 link nodes are to be used, a serial-parallel mixed connection mode can be used.

[0113] Referring to FIG. 9, in an embodiment, the LED driving circuit further includes a clock module; the clock module is configured to generate a clock signal with a frequency of 8MHz and send the clock signal to the data shaping module, the addressing control module, and the driving module, respectively.

[0114] Specifically, the clock module adopts an RC oscillation structure with a deviation within ±10%; the sampling of the driving data and the output data, and the PWM wave of the driving constant current in the driving module are all determined by the clock signal.

[0115] Further, the LED driving circuit further comprises a voltage stabilizing module; the voltage stabilizing module is used for stabilizing the power supply voltage to 5V and supplying the data shaping module, the addressing control module, the driving module and the light sensitive extraction module respectively.

[0116] Since the LED lamp is formed into a single lamp strip or a lamp strip in actual application, the lamp strip line resistance is relatively large, when the driving circuit is directly powered by the conventional 5V voltage and the distance between two lamp beads is 10cm, the maximum length of the lamp strip is 10m, which cannot meet the demand of longer length; therefore, the voltage stabilizing module LDO (Low Dropout Regulator) is added in the LED driving circuit in the present disclosure, so that the power supply voltage VDD supplied externally can be increased to 12V / 24V / 36V, etc., and the LDO in the driving circuit is used to stabilize the voltage to 5V, the influence of the line resistance is reduced, more LED lamps can be driven, and the lamp strip is longer.

[0117] In some embodiments, the frequency range of the bus data is 800kHz-1.2MHz.

[0118] Specifically, the frequency of the feedback request instruction and the lamp bead fault prompt information in the above embodiments is within the range.

[0119] The minimum frequency requirement of the master control chip MCU (Microcontroller Unit) is 8MHz, the 8MHz frequency single-chip microcomputer has a relatively high programming requirement (because the instruction period is 125ns, that is, the minimum error unit is 125ns); the higher the frequency of the MCU, the higher the frequency accuracy of the bus data DIN output, if the design limitation is not considered, the frequency of the DIN can also be higher. The performance of the MCU is the highest with a 72MHz frequency, and the DIN frequency can be about 9MHz. The brush frame frequency corresponding to the bus data is preferably not lower than 60Hz.

[0120] The number of parallel connections in Table 2 below is calculated according to the driving data of 24 bits in the bus data read by one LED driving circuit (if it is 48 bits PWM, the number of parallel connections is halved, and so on): Table 2

[0121] In some embodiments, each output port of the master control chip is provided with a pull-down resistor.

[0122] The impedance value of the pull-down resistor is between 15KΩ-20KΩ.

[0123] Specifically, when the LED display system is powered on, the bus data generated by the master control chip is unstable, so a pull-down resistor can be arranged before the first LED drive circuit of each output bus to pull down the unstable DIN signal at the power-on moment to the ground, thereby avoiding display disorder of the LED substrate.

[0124] In some embodiments, the first row of LED drive circuits on the LED substrate are connected in parallel to two output buses respectively.

[0125] Further, the first row of LED drive circuits on the LED substrate can be connected to the second output bus through a switch circuit, and when it is detected that the coordinates of the extinguished LED lamp are in the first row, the switch circuit of the fault starting coordinates is connected.

[0126] Specifically, when the input end of each LED drive circuit in the substrate is connected to the LED drive circuit in the same column of the matrix in the first row, the LED drive circuit in the first row does not have a corresponding standby input, so the disclosure sets two input buses to avoid failure of one of the input buses; since the bus data transmitted on the two input buses is consistent, the LED drive circuit in the first row does not need to update the preset address when switching the bus through the connected switch circuit.

[0127] The above embodiments set double buses for the first row of LED drive circuits on the LED substrate, realize standby input setting for all LED drive circuits, and further improve the reliability of LED lamp bead display.

[0128] In some embodiments, the maximum matrix row number of the LED substrate is 64, and the maximum matrix column number is 600.

[0129] Currently, the commonly used LED substrate module size is 25 cm wide, and the specific size is 25 cm*50 cm, 25 cm*100 cm, and 25 cm*150 cm; according to the pixel density requirement, it is divided into P2.5, P3, P3.75, P3.91, P4, P6, P6.25, P8, P10, etc. (P2.5 represents the center-to-center distance of the lamp beads is 2.5 mm, and the others are similar). Table 3 below is the maximum matrix arrangement number of different specifications according to the maximum size of 25 cm*150 cm.

[0130] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the disclosure.

[0131] The above-described embodiments are merely illustrative of several embodiments of the present disclosure, which are described in a relatively specific and detailed manner, but should not be construed as limiting the scope of the present disclosure. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the appended claims.

Claims

1. A bus control method of an LED substrate, characterized by, The application is applied to a master chip; A plurality of LED driving circuits in an LED substrate are connected in parallel to an output bus of the master chip; the method comprises: Obtaining fault information of the LED substrate; Determining coordinates of all faulty LED lamps and a fault starting coordinate among them; Taking an LED driving circuit of the LED lamp corresponding to the fault starting coordinate as a target driving circuit; Controlling a switch circuit corresponding to an input end of the target driving circuit to be connected; wherein the other end of the switch circuit is connected to an output end of the LED driving circuit corresponding to the target driving circuit in the longitudinal direction of the LED substrate; Based on the number of matrix columns of the LED substrate, updating a preset address in the LED driving circuit corresponding to each faulty LED lamp, specifically, calculating a difference value between the number of columns of the coordinates and the number of columns of the fault starting coordinate; adding the difference value and the number of matrix columns to obtain an updated preset address; and generating an addressing instruction based on the updated preset address and the coordinates and sending it to the LED driving circuit corresponding to the coordinates, so that the preset address is replaced by the updated preset address; wherein the preset address is used for the LED driving circuit to read driving data in the received bus data or output data, and control the corresponding LED lamp to display based on the driving data.

2. The bus control method of the LED substrate according to claim 1, further comprising: Sending a feedback request instruction to each LED driving circuit at a preset period; The feedback request instruction is used to make the LED driving circuit send pre-stored coordinate data; Judging whether the number of received coordinate data is equal to the product of the number of rows and columns of the LED substrate; If not equal, the fault information is generated.

3. The bus control method of the LED substrate according to claim 1, further comprising: Obtaining a brightness image of the LED substrate when powered on; Using Roberts algorithm to binarize the brightness image to obtain a binary image; Judging whether there is a black pixel point in the range corresponding to the LED substrate in the binary image; If there is, the fault information is generated.

4. The bus control method of an LED substrate according to claim 2, wherein, The determination of the coordinates of all faulty LED lamps and the fault starting coordinate among them comprises: Comparing each coordinate data and the matrix of the LED substrate to obtain the coordinates of each faulty LED lamp; Taking the coordinate with the smallest number of columns among each coordinate as the fault starting coordinate.

5. The bus control method of an LED substrate according to claim 3, wherein, The determination of the coordinates of all faulty LED lamps and the fault starting coordinate among them comprises: Generating a target grid based on the number of rows and columns of the LED substrate and the size of the LED substrate in the binary image; Aligning the target grid and the binary image to obtain the coordinates of each black pixel point; Taking the coordinate with the smallest number of columns among each coordinate as the fault starting coordinate.

6. The bus control method of the LED substrate according to claim 1, further comprising: After controlling the switch circuit to be connected, obtaining the fault information of the LED substrate again; Determining the coordinates of all faulty LED lamps; Generate lamp bead failure prompt information based on each coordinate.

7. The bus control method of the LED substrate according to claim 1, further comprising: Obtaining the usage time length of the LED driving circuit, and calculating a light compensation value based on the usage time length; Put the light compensation value into the driving data corresponding to the LED driving circuit.

8. A bus control device of an LED substrate, characterized by, Applied to a master control chip; A plurality of LED driving circuits in an LED substrate are connected in parallel to the output bus of the master control chip; the device comprises: An acquisition module for acquiring fault information of the LED substrate; A determination module for determining the coordinates of all faulty LED lamps and the fault starting coordinates among them; A target module for taking the LED driving circuit of the LED lamp corresponding to the fault starting coordinates as a target driving circuit; A control module for controlling the switch circuit corresponding to the input end of the target driving circuit to be connected; wherein the other end of the switch circuit is connected to the output end of the LED driving circuit corresponding to the target driving circuit in the LED substrate; An update module for updating the preset address in the LED driving circuit corresponding to each LED lamp based on the matrix column number of the LED substrate, specifically for calculating the difference between the column number of the coordinates and the column number of the fault starting coordinates; adding the difference and the matrix column number to obtain an updated preset address; and generating an addressing instruction based on the updated preset address and the coordinates, and sending it to the LED driving circuit corresponding to the coordinates, so that the preset address in it is replaced by the updated preset address; wherein the preset address is used by the LED driving circuit to read driving data in the received bus data or output data, and to control the corresponding LED lamp to display based on the driving data.

9. An LED display system, comprising: Comprising a master control chip and an LED substrate; The LED substrate comprises a plurality of LED devices arranged in a matrix form, the LED device comprising an LED driving circuit and an LED lamp connected to the output end of the LED driving circuit; The master control chip comprises a plurality of output ports, each of which is connected to a corresponding output bus; The input ends of each LED driving circuit in the same row of the matrix are connected in parallel to one of the output buses, and are also connected to the output ends of the longitudinally corresponding LED driving circuits in the matrix through a switch circuit; The master control chip is configured to locate a fault starting coordinate in a faulty LED lamp when obtaining fault information, control the switch circuit corresponding to the input end of the LED driving circuit corresponding to the fault starting coordinate to be in communication, and update a preset address in the LED driving circuit corresponding to each of the faulty LED lamps based on a matrix column number of the LED substrate; specifically, the master control chip is configured to calculate a difference between a column number of the coordinate and a column number of the fault starting coordinate, add the difference and the matrix column number to obtain an updated preset address, and generate an addressing instruction based on the updated preset address and the coordinate and send the addressing instruction to the LED driving circuit corresponding to the coordinate, so that the preset address in the LED driving circuit is replaced by the updated preset address. The preset address is used by the LED driving circuit to read driving data in received bus data or output data and control the corresponding LED lamp to display based on the driving data.

10. The LED display system of claim 9, wherein, The LED driving circuit comprises: a data shaping module, an addressing control module, a photosensitive extraction module, and a driving module; The data shaping module is configured to receive bus data or output data, filter the bus data or the output data to obtain serial data, and send the serial data to the addressing control module. The addressing control module is configured to read driving data in the serial data according to a preset address, intercept the serial data after the preset address as output data, send the driving data and the output data to the data shaping module, and receive an updated preset address from the photosensitive extraction module and replace the preset address. The data shaping module is further configured to send the driving data to the driving module to control the LED lamp to display according to the driving data, and send an addressing instruction to the photosensitive extraction module when the driving data includes the addressing instruction, and send the output data to an output end. The photosensitive extraction module is configured to receive a light signal after receiving the addressing instruction, convert the light signal to obtain the updated preset address, and send the updated preset address to the addressing control module.

11. The LED display system of claim 10, wherein, The data shaping module is configured to filter out pulses with a frequency greater than 33 MHz in the bus data or the output data.

12. The LED display system of claim 10, wherein, The driving module is configured to generate a driving current according to the driving data and send the driving current to the corresponding LED lamp; the driving current ranges from 0.3 mA to 25 mA.

13. The LED display system of claim 10, wherein, The addressing control module comprises an address storage unit configured to store the preset address; the address storage unit has a maximum storage bit number of 12 bits.

14. The LED display system of claim 10, wherein, Further comprising a clock module; The clock module is configured to generate a clock signal with a frequency of 8 MHz and send the clock signal to the data shaping module, the addressing control module, and the driving module, respectively.

15. The LED display system of claim 10, wherein, Further comprising a voltage stabilizing module; The voltage stabilizing module is configured to stabilize a power supply voltage to 5 V and supply the voltage to the data shaping module, the addressing control module, the driving module, and the photosensitive extraction module, respectively.

16. The LED display system of claim 9, wherein, The frequency range of the bus data is 800 kHz-1.2 MHz.

17. The LED display system of claim 9, wherein, Each of the output ports of the master chip is provided with a pull-down resistor, and the impedance value of the pull-down resistor is between 15 KΩ and 20 KΩ.

18. The LED display system of claim 9, wherein, Each of the LED driving circuits in the first row is connected in parallel to two output buses on the LED substrate.

19. The LED display system of claim 9, wherein, The maximum matrix row number of the LED substrate is 64, and the maximum matrix column number is 600.

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