LED driving circuit, single-wire communication device and method

Abstract

The present invention discloses an LED driving circuit, a single-line communication device and a method, wherein the single-line communication method for an LED display system comprises: utilizing a first data port and a second data port of a plurality of LED driving circuits to cascade the plurality of LED driving circuits; utilizing a first data port of a controller to provide a driving data packet and utilizing a second data port of the controller to receive a status data packet; a front-stage LED driving circuit in the plurality of LED driving circuits forwards a front-stage status data packet and a rear-stage driving data packet to a rear-stage LED driving circuit, thereby realizing single-line control of the writing of LED driving circuit data and returning the status data to the controller, and the return data channel does not require an additional wiring channel to reduce the wiring area.

Description

Technical Field

[0001] The present invention relates to electronic circuits, and more particularly to an LED driving circuit, a single-line communication device and a method for an LED display system. Background Art

[0002] LEDs are widely used in display systems as self-luminous elements. In LED displays, LEDs are used as pixel elements to display images. In liquid crystal displays (LCDs), LEDs are used as light sources to provide backlight. As display quality improves, the number of LEDs used in display systems is increasing, whether as pixel units or light sources.

[0003] In a liquid crystal display, the liquid crystal molecules themselves do not emit light. The LED array in the backlight module (BLU) forms a surface light source, providing sufficient brightness and evenly distributed backlight. The luminous effect and color gamut range of the backlight module affect the display quality of the LCD. With the market demand for high-quality display screens, multi-partition direct-type mini-LED backlight technology has been developed to achieve high brightness, high color gamut, high contrast and energy saving for LCD displays.

[0004] In the prior art, in order to realize the control of LED, it is necessary to set up multiple LED driving circuits, and further control the LED by controlling the driving circuits through a controller. The existing single-line chain interface method can only realize the function of the controller writing data to each driving circuit, and does not have the function of reading the data of each driver. The function menu is relatively simple and has great limitations. Summary of the invention

[0005] In view of the above problems, an object of the present invention is to provide an LED driving circuit, a single-line communication device and a method, so as to solve the technical problems mentioned in the above-mentioned prior art.

[0006] According to one aspect of the present invention, there is provided a single-line communication method for an LED display system, comprising:

[0007] Utilizing the first data ports and the second data ports of the plurality of LED driving circuits, cascading the plurality of LED driving circuits to each other;

[0008] Providing a driving data packet using a first data port of the controller and receiving a status data packet using a second data port of the controller;

[0009] The preceding LED driving circuit in the plurality of LED driving circuits forwards the preceding status data packet and the succeeding driving data packet to the succeeding LED driving circuit. Optionally, the plurality of LED driving circuits start to obtain current-stage driving data from the driving data packet forwarded by the controller or the preceding LED driving circuit based on the write flag in the driving data packet, and simultaneously forward the current-stage status data packet.

[0010] Optionally, the multiple LED driving circuits start to obtain current-stage driving data from the driving data packet forwarded by the controller or the previous-stage LED driving circuit based on the write flag, and simultaneously forward current-stage status data packet and the write flag.

[0011] Optionally, the plurality of LED driving circuits obtain current-level driving data based on an interval mark in the driving data packet; or

[0012] The plurality of LED driving circuits obtain current-level driving data based on the fixed length in the driving data packet.

[0013] Optionally, when the multiple LED driving circuits acquire current-stage driving data based on a fixed length in the driving data packet, the multiple LED driving circuits are configured so that the length of the status data packet is less than or equal to the length of the driving data packet.

[0014] Optionally, the driving data packet includes vacant data bits.

[0015] Optionally, the current-stage status data packet includes a read flag, and the plurality of LED driving circuits forward the previous-stage status data packet based on the read flag in the received status data packet.

[0016] Optionally, the multiple LED driving circuits obtain current-stage driving data and complete switching to a buffer mode. In the buffer mode, a front-stage LED driving circuit among the multiple LED driving circuits directly forwards a subsequent-stage driving data packet to a subsequent-stage LED driving circuit.

[0017] Optionally, the status data packets of the plurality of driving circuits are forwarded to the second data port of the controller via the second data port of the last-stage LED driving circuit among the plurality of LED driving circuits.

[0018] According to another aspect of the present invention, a single-line communication device for an LED display system is provided, comprising: a plurality of LED driving circuits, each of which comprises a first data port and a second data port, wherein the plurality of LED driving circuits are cascaded with each other using the first data port and the second data port,

[0019] A controller, the controller comprising a first data port and a second data port, the first data port being used to provide a driving data packet, and the second data port being used to receive a status data packet;

[0020] The first data port of the first-stage LED driving circuit among the plurality of LED driving circuits is connected to the first data port of the controller, and the second data port of the last-stage LED driving circuit among the plurality of LED driving circuits is connected to the second data port of the controller.

[0021] A preceding LED driving circuit among the plurality of LED driving circuits forwards a status data packet of the preceding stage and a driving data packet of the succeeding stage to a succeeding LED driving circuit.

[0022] Optionally, the plurality of LED driving circuits obtain current-stage driving data from a driving data packet forwarded by a previous-stage LED driving circuit based on a separation mark or a fixed length in the driving data packet, and simultaneously forward current-stage status data packets; or

[0023] The multiple LED driving circuits start to obtain current-stage driving data from the driving data packet forwarded by the controller or the previous-stage LED driving circuit based on the write flag, and simultaneously forward the current-stage status data packet and the write flag.

[0024] Optionally, the multiple LED driving circuits obtain current-stage driving data and complete switching to a buffer mode. In the buffer mode, a front-stage LED driving circuit among the multiple LED driving circuits directly forwards a subsequent-stage driving data packet to a subsequent-stage LED driving circuit.

[0025] According to another aspect of the present invention, there is provided an LED driving circuit for an LED display system, comprising:

[0026] A first data port and a second data port are used for cascading with a plurality of LED driving circuits;

[0027] A plurality of driving control units, used for connecting to a plurality of LEDs and performing driving control;

[0028] A serial shift unit, used to intercept data corresponding to the LED driving circuit at this level in the driving data packet;

[0029] Among them, the second data port in the LED driving circuit forwards the status data packet of the previous stage and the driving data packet of the subsequent stage to the subsequent LED driving circuit, and the first data port in the LED driving circuit is used to receive the status data packet and driving data packet forwarded by the previous stage LED driving circuit.

[0030] Optionally, the LED driving circuit is configured as:

[0031] Based on the separation mark or fixed length in the driving data packet, the current-stage driving data packet is obtained from the driving data packet forwarded by the previous-stage LED driving circuit, and the current-stage status data packet is forwarded at the same time.

[0032] The present invention provides a single-line communication device and method, which realizes cascading of multiple LED driving circuits by using the first data port and the second data port of multiple LED driving circuits; provides a controller including a first data port and a second data port, wherein the first data port is used to provide a driving data packet, and the second data port is used to receive a status data packet, wherein the first data port of the first-stage LED driving circuit in the multiple LED driving circuits is connected to the first data port of the controller, and the second data port of the last-stage LED driving circuit in the multiple LED driving circuits is connected to the second data port of the controller, and the front-stage LED driving circuit in the multiple LED driving circuits forwards the status data packet of the front stage and the driving data packet of the rear stage to the rear-stage LED driving circuit. The status data packet is forwarded stage by stage, which is different from the prior art in which the controller can only write the driving data packet to the LED driver. The present invention realizes the writing of data of the single-line chain-type control LED driving circuit and returns the status data to the controller.

[0033] In a preferred embodiment, by reducing the write flags and / or flags in the drive data packet, the speed of the write operation is further improved and the time of the write operation is shortened.

[0034] In a preferred embodiment, by configuring the LED driving circuit buffer mode, after the multiple LED driving circuits enter the buffer mode, the output is updated based on the frame end identifier in the driving data packet, and the function of synchronous triggering required in the display system to implement a certain action (such as synchronously updating the output) is retained.

[0035] In the above-mentioned single-wire communication device and method, the data channel for returning the status data to the controller does not require an additional wiring channel, thus reducing the wiring area. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0037] Figure 1 A schematic block diagram of a backlight module according to a first embodiment of the present invention is shown;

[0038] Figure 2 shows a schematic block diagram of an LED display system according to a second embodiment of the present invention;

[0039] Figure 3 A schematic block diagram of a single-wire communication device in the prior art is shown.

[0040] Figure 4 A flow chart showing a single-wire communication method of the prior art.

[0041] Figure 5 A waveform diagram showing a single-wire communication method of the prior art.

[0042] Figure 6 A schematic block diagram of a single-wire communication device according to a third embodiment of the present invention is shown.

[0043] Figure 7 A flow chart showing a single-wire communication method according to a fourth embodiment of the present invention is shown.

[0044] Figure 8 A waveform diagram showing a single-wire communication method according to a fourth embodiment of the present invention.

[0045] Fig. 9 A waveform diagram showing a single-wire communication method according to a fifth embodiment of the present invention.

[0046] Fig.10 A waveform diagram showing a single-wire communication method according to a sixth embodiment of the present invention. DETAILED DESCRIPTION

[0047] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the detailed description of the present invention below, some specific details are described in detail. It is possible for a person skilled in the art to fully understand the present invention without the description of these details. In order to avoid confusing the essence of the present invention, known methods, processes, flows, components and circuits are not described in detail.

[0048] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0049] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be an intermediate element, and the connection between the elements can be physical, logical, or a combination thereof. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0050] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising" and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0051] In the description herein, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description herein, unless otherwise specified, "plurality" means two or more.

[0052] In the description of this article, the terms "first-stage LED driving circuit" and "final-stage LED driving circuit", and "first data port" and "second data port" are defined according to the connection relationship between the LED driving circuit and the first data port SDO of the controller.

[0053] In the data channel, the "first data port" of the "first-stage LED driving circuit" is directly connected to the first data port SDO of the controller, the "last-stage LED driving circuit" is the last LED driving circuit of the data channel, and the "first data port" of the "last-stage LED driving circuit" is connected to the second data port of the previous-stage LED driving circuit.

[0054] Figure 1 A schematic block diagram of a backlight module according to a first embodiment of the present invention is shown.

[0055] The backlight module 100 includes a controller 110 , a plurality of LED driving circuits 120 - 1 to 120 - i , and a plurality of LED blocks 130 - 1 to 130 - i , wherein i represents any natural number.

[0056] In a liquid crystal display, the liquid crystal panel includes a TFT array substrate, a color filter, and a liquid crystal layer sandwiched between the two. The TFT array substrate is used to control the transmittance of the liquid crystal layer. The backlight module 100 is located below the array substrate and provides backlight as a light source. After passing through the liquid crystal panel, the luminous brightness corresponding to the pixel grayscale can be obtained.

[0057] In this embodiment, the LED blocks 130-1 to 130-i respectively include a plurality of LEDs 131 arranged in an array. The LED blocks 130-1 to 130-i themselves are also arranged in an array, so that a plurality of point light sources are used to form a surface light source.

[0058] In this embodiment, in the LED blocks 130-1 to 130-i, the cathodes of each column of LEDs are connected together and connected to a corresponding current driving terminal of the LED driving circuit, and the anodes of each row of LEDs are connected together and the anodes of all rows of LEDs are commonly connected to the power supply terminal. Therefore, the brightness of the corresponding column of LEDs can be changed by adjusting the duty cycle or amplitude of the current at the current driving terminal of the LED driving circuit according to the brightness data. In an alternative embodiment, in the LED blocks 130-1 to 130-i, the anodes of each column of LEDs can be connected to their respective power supply terminals for independent power supply, or the anodes of at least some columns of LEDs are connected to the same power supply terminal for independent power supply. In an alternative embodiment, the plurality of LEDs 131 in the backlight module 100 are arranged in an array, but connected into a single LED string, and the cathode of the LED string is connected to a corresponding current driving terminal of the LED driving circuit. Therefore, a single current driving terminal of the LED driving circuit can also drive all LEDs of an LED block.

[0059] The controller 110 includes a first data port SDO and a second data port SDI. In this embodiment, although not shown in the figure, the controller 110 can be connected to the previous image processing engine SOC via an SPI bus or other communication bus to receive image data or brightness data.

[0060] The LED driving circuits 120-1 to 120-i respectively include a first data port SDI, a second data port SDO, and current driving terminals OUT0 to OUTn, where n represents any natural number. The LED driving circuits 120-1 to 120-i are cascaded to each other to provide a data channel SD, that is, the second data port SDO of the preceding LED driving circuit is connected to the first data port SDI of the succeeding LED driving circuit, and in the data channel SD, the second data port of the last LED driving circuit is connected to the second data port SDI of the controller.

[0061] Furthermore, the first data port SDO of the controller 110 is connected to the first data port SDI of the first-stage LED driving circuit among the LED driving circuits 120-1 to 120-i, and the second data port SDI of the controller 110 is connected to the second data port SDO of the last-stage LED driving circuit among the LED driving circuits 120-1 to 120-i. Therefore, the controller 110 can transmit a driving data packet via a data channel and receive data returned by the last-stage LED driving circuit. The driving data packet includes at least one of brightness data, configuration data, and address data.

[0062] In this embodiment, the first data port SDI of the first-stage LED driving circuit 120-1 is connected to the first data port SDO of the controller 110 via the data channel SD, and the second data port SDO of the last-stage LED driving circuit 120-i is connected to the second data port SDI of the controller 110. The first data port SDI and the second data port SDO of the LED driving circuits 120-1 to 120-i are both three-state ports, which can be configured as one of the input port and the output port. The physical connection of the SD data channel is a single line, which is a single data line in the case of a single line, and can be a data line and a clock line, or two differential data lines in the case of a double line. In this embodiment, even if the SD data channel does not use a clock line, ultra-high-speed data transmission can be achieved through embedded clock technology.

[0063] Figure 2 A schematic block diagram of an LED display system according to a second embodiment of the present invention is shown.

[0064] The LED display system 200 includes a controller 110, a plurality of LED driving circuits 120-1 to 120-i, a plurality of LED blocks 130-1 to 130-i, a row driver 140, and a switch array 210, wherein i represents any natural number. In the present embodiment, the LED blocks 130-1 to 130-i respectively include a plurality of LEDs 131 arranged in an array. The LED blocks 130-1 to 130-i themselves are also arranged in an array. The anodes of the same row of LEDs in the plurality of LEDs 131 are connected to a corresponding row line among the row lines S1 to Sm, and the cathodes of the same column of LEDs are connected to a corresponding column line among the column lines P1-1 to Pi-n.

[0065] In the LED display system, LEDs are used as sub-pixel units. When displaying an image, the luminance corresponds to the sub-pixel grayscale of the image, and a plurality of sub-pixel units are used to form a pixel array. It can be understood that each sub-pixel in the LED display system corresponds to a red, green or blue sub-pixel unit. For example, when displaying a color image, three adjacent LEDs can be used to display the red, green and blue color components respectively, and each LED generates light of the corresponding color according to its own lighting characteristics, or an additional filter is used to generate light of the corresponding color.

[0066] The switch array 210 includes a plurality of switches 211. The row lines S1 to Sm are connected to a power supply terminal via a corresponding one of the plurality of switches 211. The row driver 140 is connected to the switch array 210 and is used to provide switch driving data to the plurality of switches in the switch array 210.

[0067] The controller 110 includes a first data port SDO and a second data port SDI. In this embodiment, although not shown in the figure, the controller 110 can be connected to the previous image processing engine SOC via an image communication bus (LVDS or VBYONE) to receive image data or brightness data.

[0068] The LED driving circuits 120-1 to 120-i respectively include a first data port SDI, a second data port SDO, and current driving terminals OUT0 to OUTn, where n represents any natural number. In the LED display system, the LED driving circuits 120-1 to 120-i are collectively used as column drivers of the LED display system. Each LED driving circuit includes a plurality of current driving terminals OUT1 to OUTn. The current driving terminals of the plurality of LED driving circuits 120-1 to 120-i are respectively connected to a corresponding column line among the column lines P1-1 to Pi-n.

[0069] Further, the LED driving circuits 120-1 to 120-i are cascaded with each other to provide a data channel SD, that is, the second data port SDO of the previous stage LED driving circuit is connected to the first data port SDI of the subsequent stage LED driving circuit, and in the data channel SD, the second data port of the last stage LED driving circuit is connected to the second data port SDI of the controller.

[0070] Furthermore, the first data port SDO of the controller 110 is connected to the first data port SDI of the first-stage LED driving circuit among the LED driving circuits 120-1 to 120-i, and the second data port SDI of the controller 110 is connected to the second data port SDO of the last-stage LED driving circuit among the LED driving circuits 120-1 to 120-i. Therefore, the controller 110 can transmit a driving data packet via a data channel and receive data returned by the last-stage LED driving circuit. The driving data packet includes at least one of brightness data, configuration data, and address data.

[0071] In this embodiment, the first data port SDI of the first-stage LED driving circuit 120-1 is connected to the first data port SDO of the controller 110 via the data channel SD, and the second data port SDO of the last-stage LED driving circuit 120-i is connected to the second data port SDI of the controller 110. The first data port SDI and the second data port SDO of the LED driving circuits 120-1 to 120-i are both three-state ports, which can be configured as one of the input port and the output port. The physical connection of the SD data channel is a single line, which is a single data line in the case of a single line, and can be a data line and a clock line, or two differential data lines in the case of a double line. In this embodiment, even if the SD data channel does not use a clock line, ultra-high-speed data transmission can be achieved through embedded clock technology.

[0072] In the display mode of the LED display system 200, the grayscale data of the image pixels is transmitted via the data channel SD. The row driver 140 scans row by row and connects the row lines to the power supply end in turn. Accordingly, the multiple current driving ends in the multiple LED driving circuits 120-1 to 120-i respectively apply constant current to the multiple LEDs in the row. The current of the current driving end of the LED driving circuit is adjusted in duty cycle or amplitude according to the grayscale data of the image pixel, which can change the equivalent current size of the multiple LEDs on the current display row, thereby displaying a pixel row of the image. In a frame period, the cumulative effective time of each LED in the pixel array is consistent with the grayscale data of the corresponding image pixel.

[0073] Figure 3 A schematic block diagram of a single-wire communication device in the prior art is shown.

[0074] The single-line communication device 11 includes a controller 110 and a plurality of LED driving circuits 120-1 to 120-i. The controller 110 includes a first data port SDO. The LED driving circuits 120-1 to 120-i are cascaded to each other to provide a data channel SD, that is, the second data port SDO of the preceding LED driving circuit is connected to the first data port SDI of the succeeding LED driving circuit.

[0075] Furthermore, the first data port SDO of the controller 110 is connected to the first data port SDI of the first-stage LED driving circuit among the LED driving circuits 120 - 1 to 120 - i. Therefore, the controller 110 can transmit display data via the data channel.

[0076] Figure 4 and Figure 5 The flowchart and waveform diagram of the single-wire communication method in the prior art are respectively shown.

[0077] Among them, based on the data packet forwarded on the data channel SD, the method is applied, for example, Figure 3 The single-wire communication device shown below refers to Figure 3 The single-wire communication device shown describes the main steps of the single-wire communication method.

[0078] Specifically, in the configuration mode of the LED driving circuit, the single-wire communication device 11 performs the following steps S01 to S04 .

[0079] In step S01 , the controller TX sends a display data packet of the LED driving circuit to the data channel SD.

[0080] See also Figure 5 , the first data port SDO of the controller 110 sends a data packet SD_Tx, which includes driving data packets DW1 to DWi of different levels of LED driving circuits, and a separation mark [E], wherein the separation mark [E] represents the data packet interval, wherein a separation mark [E] is set between two consecutive driving data packets DWn, i is the number of LED driving circuits, and n is any integer from 1 to i.

[0081] In step S02, the plurality of LED driving circuits sequentially obtain the display data of the current stage and generate the data packet of the subsequent stage based on the separation mark [E].

[0082] Taking the first-stage LED driving circuit 120-1 as an example, when the first-stage LED driving circuit 120-1 obtains the current-stage data from the data packet SD_Tx and obtains the separation mark [E], it means that the current-stage driving circuit data packet has been received. The first-stage LED driving circuit will write the remaining data sent by the controller to generate a subsequent-stage data packet.

[0083] In step S03, the plurality of LED driving circuits enter a buffer mode to forward subsequent data packets.

[0084] Taking the first-stage driving circuit 120-1 as an example, after the first-stage LED driving circuit 120-1 receives the data packet sent by the controller 110, the first-stage LED driving circuit 120-1 will change to the buffer mode, that is, the first data port SDI and the second data port SDO are connected SDO=SDI, and the subsequent-stage data packet generated above is forwarded, and the data of the subsequent-stage data packet is received by the subsequent-stage LED driving circuit.

[0085] In step S04, the plurality of LED driving circuits exit the buffer mode and stop forwarding based on the frame end identifier.

[0086] Multiple LED driving circuits enter the buffer mode to forward the next-stage data packet. The last-stage LED driving circuit 120-i obtains the data packet forwarded from the previous stage. After writing the data of this stage, all LED driving circuits can receive the data sent by the controller 110. The controller 110 triggers all LED driving circuits to update the output by sending a frame end mark [L], exits the buffer mode, stops forwarding and waits for the arrival of the next frame of data.

[0087] The above single-line communication method can only realize the function of the controller writing data to each drive circuit, but does not have the function of reading data from each driver. The function menu is relatively simple and has great limitations.

[0088] Figure 6 A schematic block diagram of a single-wire communication device according to a third embodiment of the present invention is shown.

[0089] The single-line communication device 11 includes a controller 110 and a plurality of LED driving circuits 120-1 to 120-i. As described above, in the backlight module, the single-line communication device 11 is used to transmit a driving data packet and receive data returned by the last-stage LED driving circuit. The driving data packet includes at least one of data brightness data, configuration data, and address data. In the LED display system, the driving data packet includes at least one of grayscale data, configuration data, and verification data.

[0090] The controller 110 includes a first data port SDO and a second data port SDI. The first data port is used to provide a driving data packet, and the second data port is used to receive a status data packet. In this embodiment, although not shown in the figure, the controller 110 can be connected to the previous image processing engine SOC via an SPI bus to receive image data or brightness data.

[0091] Further, the LED driving circuits 120-1 to 120-i are cascaded with each other to provide a data channel SD, that is, the second data port SDO of the previous stage LED driving circuit is connected to the first data port SDI of the subsequent stage LED driving circuit, and in the data channel SD, the second data port of the last stage LED driving circuit is connected to the second data port SDI of the controller.

[0092] Furthermore, the first data port SDO of the controller 110 is connected to the first data port SDI of the first-stage LED driving circuit among the LED driving circuits 120-1 to 120-i, and the second data port SDI of the controller 110 is connected to the second data port SDO of the last-stage LED driving circuit among the LED driving circuits 120-1 to 120-i. Therefore, the controller 110 can transmit at least one of brightness data, configuration data, and address data through the data channel and receive data returned by the last-stage driving circuit.

[0093] In this embodiment, the first data port SDI of the first-stage LED driving circuit 120-1 is connected to the first data port SDO of the controller 110 via the data channel SD, and the second data port SDO of the last-stage LED driving circuit 120-i is connected to the second data port SDI of the controller 110. The first data port SDI and the second data port SDO of the LED driving circuits 120-1 to 120-i are both three-state ports, which can be configured as one of the input port and the output port. The physical connection of the SD data channel is a single line, which is a single data line in the case of a single line. In this embodiment, even if the SD data channel does not use a clock line, ultra-high-speed data transmission can be achieved through embedded clock technology.

[0094] When the backlight module chip is powered on, the front-stage image processing engine SOC provides driving data to the controller 110 via the control interface according to the set power-on timing, and the controller 110 performs a power-on initialization action.

[0095] After the controller 110 is powered on and initialized, the controller 110 can be in one of a display mode and an upgrade mode. In the display mode of the controller 110, the front-stage image processing engine SOC sends brightness data to the controller 110 via the SPI bus. The controller 110 processes the brightness data and then sends it to the LED drive circuits 120-1 to 120-i. The LED drive circuits 120-1 to 120-i adjust the duty cycle or amplitude of the current at the current driving end according to the brightness data, thereby changing the brightness of the corresponding column LED. In the upgrade mode of the controller 110, the front-stage image processing engine SOC sends upgrade data to the controller 110 via the SPI bus. The controller 110 uses the upgrade data to update the current level program or data, so that the online upgrade function can be realized after leaving the factory to improve the user experience.

[0096] Figure 7 and Figure 8 The flowchart and waveform diagram of the single-line communication method according to the fourth embodiment of the present invention are respectively shown. Figure 6 The single-wire communication device shown below refers to Figure 3 The single-wire communication device shown describes the main steps of the single-wire communication method.

[0097] Specifically, in the configuration mode of the LED driving circuit, the single-wire communication device 11 performs the following steps S11 to S16 .

[0098] In step S11 , the controller sends a driving data packet of a plurality of LED driving circuits.

[0099] See also Figure 8, the first data port SDO of the controller 110 sends a driving data packet SD_Tx which is transmitted step by step via the data channel SD. The driving data packet SD_Tx includes a [W] flag, an [E] flag, an [R] flag, driving data packets DW1 to DWi of different levels of LED driving circuits, and in addition, the data channel SD can also transmit status data packets DR1 to DRi of different levels of LED driving circuits, wherein the [W] flag is a header of a write operation, indicating that a write operation is to be performed (hereinafter referred to as a write flag [W]), and the [E] flag indicates a separation flag (hereinafter referred to as a separation flag [E]), wherein a continuous driving data packet DWn is set between each two. There is a separation mark [E], a [W] mark is set before the driving data packet DWn, the [R] mark is the header of the read operation, and an [R] mark is set before the status data packet DRn, wherein i is the number of LED driving circuits, and n is any integer from 1 to i. The driving data packet includes at least one of a configuration data packet, a brightness data packet, and a display data packet. When different data packets are included, the driving data packets DW1 to DWi can be changed accordingly. It should be noted that an [R] mark is set before the status data packet DRn, and the [R] mark is the data in the data packet DRn. For clearer representation in the attached drawings, separate descriptions are used.

[0100] In step S12, the plurality of LED driving circuits sequentially obtain current level data based on the separation mark.

[0101] Taking the n-th level LED driving circuit 120-n as an example, the n-th level LED driving circuit 120-n obtains data of this level from the driving data packet or the driving data packet forwarded by the previous level LED driving circuit, that is, the first level LED driving circuit obtains data of this level from the driving data packet forwarded by the controller, and other level LED driving circuits obtain driving data of this level from the driving data packet forwarded by the previous level LED driving circuit. When the write mark [W] is obtained, the driving data packet DWn of this level is received, and at the same time, the LED driving circuit of this level forwards the status data packet DRn of this level, that is, the driving data of this level is written and the status data packet DRn of this level is forwarded to the next level LED driving circuit at the same time. After the (n+1)-th level LED driving circuit 120-(n+1) receives the [R] mark in the previous level status data packet, it will forward the [R] mark to the next level, that is, the (n+2)-th level LED driving circuit 120-(n+2) and shift the output of the n-th level status data packet, and so on, until it is forwarded to the last level LED driving circuit 120-i.

[0102] When the separation mark [E] is obtained, the driving data of this level is obtained based on the separation mark [E] in the driving data packet, that is, the driving data packet of the current level LED driving circuit has been received, and the driving data packet will continue to be received by the next level LED. Therefore, when the current level LED driving circuit forwards the status data packet DRn of this level, it needs to be faster than the current level LED driving circuit receives the driving data packet, that is, the data packet length of DRn is less than or equal to the data packet length of DWn, so as to ensure that when the current level LED driving circuit completes receiving the driving data, the next level driving circuit has completed receiving the status data packet of this level and is ready to receive the driving data of the next level.

[0103] In one embodiment, the separator mark [E] is optional, such as Fig. 9 As shown, multiple LED driving circuits can be configured in advance to obtain the current level driving data based on the fixed length in the driving data packet after receiving the current level driving data of the predetermined length, that is, the current level LED driving circuit has completed receiving the driving data packet. The above-mentioned predetermined length is a fixed length. In a preferred embodiment, multiple LED driving circuits are configured to have the same fixed length to meet the needs of unified configuration. However, due to the shift timing requirements, the status data packet DRn read out at this time needs to be at least one [R] mark width shorter than DWn to ensure that when the current level LED driving circuit completes receiving the driving data, the next level driving circuit has completed receiving the status data packet of the current level and is ready to receive the driving data of the next level.

[0104] Based on the above embodiments, Fig.10 , the write flag [W] in the driving data packet can be omitted, that is, the write flag [W] is forwarded in a step-by-step forwarding manner. The first-level LED driving circuit 120-1 receives the driving data packet forwarded by the controller 110, and when the write flag [W] is obtained, it starts to receive the driving data packet DW1 of this level. At the same time, the LED driving circuit of this level forwards the status data packet DR1 of this level, and inserts the write flag [W] at the end of the status data packet DR1 and forwards it to the second-level LED driving circuit, further improving the speed of the write operation and shortening the time of the write operation. At the same time, it is also necessary to shorten the length of the status data in the forwarded status data packet. In this embodiment, the sum of the length of the status data packet DRn and the write flag [W] needs to be less than or equal to the length of the driving data packet DWn.

[0105] The above-mentioned embodiments can be combined with each other, and the present invention does not limit this. In the above-mentioned embodiments, when there is a size relationship or a length limitation between the lengths of the status data packets DRn of each level and the driving data packets DWn of each level, the length of the data packet can be controlled by adding dummy data bits in the above-mentioned driving data packets, thereby controlling the size relationship between the lengths of the status data packets DRn of each level and the driving data packets DWn of each level.

[0106] In step S13 , a front-stage LED driving circuit among the plurality of LED driving circuits enters a buffer mode to forward a rear-stage driving data packet to a rear-stage LED driving circuit.

[0107] Taking the n-th level driving circuit as an example, when the n-th level driving circuit 120-n obtains the write mark [W], while starting to receive the driving data packet DWn of the current level, it will also forward the status data packet DRn of the LED driving circuit of the current level, and obtain the driving data of the current level based on the separation mark [E] or the fixed length in the driving data packet. After obtaining the separation mark [E] or obtaining the fixed length in the driving data packet, the current level driving circuit has completed obtaining the driving data of the current level, and the n-th level LED driving circuit 120-n will directly forward the next-level driving data packet to the next-level LED driving circuit.

[0108] In detail, the data packets received by the n-th level LED driving circuit include the previous n-1 level status data packets DR1 to DR(n-1) and the driving data packets of the n-th level and subsequent level LED driving circuits 120-n to 120-i. Before obtaining the driving data packet DWn of this level, the above-mentioned status data packets DR1 to DR(n-1) are forwarded. When the write mark [W] is obtained, the driving data packet DWn of this level is started to be obtained, and the status data packet DRn of the LED driving circuit of this level is forwarded at the same time. After the acquisition and forwarding are completed, the n-th level LED driving circuit 120-n will be converted to the buffer mode, that is, the first data port SDI and the second data port SDO are connected SDO=SDI. In this buffer mode, the n-th level LED driving circuit 120-n will directly forward the driving data packets of the (n+1)-th level and subsequent level LED driving circuits 120-(n+1) to 120-i, that is, the subsequent level driving data packets of the n-th level LED driving circuit. The above-mentioned status data packets DR1 to DRn are arranged in sequence before the above-mentioned subsequent driving data packets, and are separated by [R] marks.

[0109] In step S14, the last stage LED driving circuit sends a status data packet to the controller.

[0110] In this embodiment, the second data port SDO of the last-stage LED driving circuit 120-i is connected to the second data port SDI of the controller. The data packets received by the last-stage LED driving circuit include the status data packets DR1 to DR(i-1) of the previous i-1 stage and the last-stage driving data packet. Before acquiring the driving data packet DWn of this stage, the above-mentioned status data packets DR1 to DR(i-1) are forwarded. When the write flag [W] is acquired, the driving data packet DWi of this stage is started to be acquired, and the status data packet DRi of the LED driving circuit of this stage is forwarded at the same time. The status data packet forwarded by the last-stage LED driving circuit is returned to the second data port SDI of the controller through the second data port SDO of the last-stage LED driving circuit 120-i. That is, multiple LED driving circuit status data packets are returned to the second data port SDI of the controller via the data channel SD.

[0111] In step S15, the plurality of LED driving circuits exit the buffer mode and stop forwarding based on the frame end identifier.

[0112] The last-stage LED driving circuit 120-i obtains the driving data packet DWi of this stage and forwards the status data DRi of the LED driving circuit of this stage. After the acquisition and forwarding are completed, the last-stage LED driving circuit 120-i also changes to the buffer mode. At this time, all LED driving circuits enter the buffer mode, that is, all LED driving circuits can receive the data sent by the controller 110. The controller 110 triggers all LED driving circuits to update the output by sending the frame end mark [L], exits the buffer mode, stops forwarding and waits for the arrival of the next frame of data.

[0113] The above-mentioned single-line communication method realizes cascading of multiple LED driving circuits by utilizing the first data port and the second data port of multiple LED driving circuits; provides a controller including a first data port and a second data port, wherein the first data port is used to provide a driving data packet, and the second data port is used to receive a status data packet, the first data port of the first-stage LED driving circuit in the multiple LED driving circuits is connected to the first data port of the controller, the second data port of the last-stage LED driving circuit in the multiple LED driving circuits is connected to the second data port of the controller, and the previous-stage LED driving circuit in the multiple LED driving circuits forwards the previous-stage status data packet and the next-stage driving data packet to the next-stage LED driving circuit. The status data packet is forwarded step by step, which is different from the prior art in which the controller can only write the driving data packet to the LED driver. The present invention realizes the writing of data of the LED driving circuit in a single-line chain type control and returns the status data to the controller.

[0114] By configuring the LED drive circuit buffer mode, after multiple LED drive circuits enter the buffer mode, the output is updated based on the frame end identifier in the drive data packet. The function of synchronous triggering required in the display system to implement a certain action (such as synchronously updating the output) is retained.

[0115] In the above-mentioned single-wire communication device and method, the data channel for returning the status data to the controller does not require an additional wiring channel, thus reducing the wiring area.

[0116] The present invention further provides an LED driving circuit 120 for driving an LED 131. The LED driving circuit 120 includes:

[0117] The LED driving circuit 120 comprises a first data port and a second data port. The second data port in the LED driving circuit forwards the status data packet of the previous stage and the driving data packet of the next stage to the next stage LED driving circuit. The first data port in the LED driving circuit is used to receive the status data packet and the driving data packet forwarded by the previous stage LED driving circuit. The first data port and the second data port are used to cascade with multiple LED driving circuits to provide a data channel; a serial shift unit that receives external driving data in a single-line communication manner and intercepts the driving data corresponding to the LED driving circuit 120 in the driving data. In this embodiment, the LED driving circuit 120 receives external driving data through a single port SDI, which simplifies the control protocol. The external driving data includes driving data corresponding to the LED driving circuit 120 and other driving data.

[0118] A driving control unit is connected to the output end of the serial shift unit and drives and controls the corresponding LED 131 according to the driving data intercepted by the serial shift unit.

[0119] A shaping output unit is connected to the output end of the serial shift unit and shapes and outputs the remaining data in the driving data after being intercepted by the serial shift unit.

[0120] In one embodiment, the status data packet sent by the LED driving circuit 120 to the subsequent LED driving circuit may include the shifted output of the driving data packet DWn received by each LED driving circuit after being intercepted by the serial shift unit, and then returned to the controller for data verification, that is, the shaping output unit shapes the remaining data in the driving data after being intercepted by the serial shift unit, processes the driving data representing data 1 and data 0 in the remaining data, and outputs the corresponding standard data 1 or data 0 to the subsequent LED driving circuit. The above embodiment returns the shifted output of DWn received by each LED driving circuit to the controller 110 to implement data verification.

[0121] As an embodiment of the present invention, the LED driving circuit 120 further includes: a storage unit connected between the serial shift unit and the driving control unit for storing the driving data intercepted by the serial shift unit. In this embodiment, the storage unit may be composed of a plurality of registers.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A single-line communication method for an LED display system, comprising: Utilizing the first data ports and the second data ports of the plurality of LED driving circuits, cascading the plurality of LED driving circuits to each other; Providing a driving data packet using a first data port of the controller and receiving a status data packet using a second data port of the controller; The preceding LED driving circuit in the plurality of LED driving circuits forwards a preceding state data packet and a succeeding driving data packet to a succeeding LED driving circuit, The plurality of LED driving circuits forward the status data packet of the current stage while acquiring the driving data of the current stage from the driving data packet.

2. The single-wire communication method according to claim 1, further comprising: The plurality of LED driving circuits start to obtain current-stage driving data from the driving data packet forwarded by the controller or the previous-stage LED driving circuit based on the write flag in the driving data packet.

3. The single-wire communication method according to claim 1, further comprising: The multiple LED driving circuits start to obtain current-stage driving data from the driving data packet forwarded by the controller or the previous-stage LED driving circuit based on the write flag and forward the write flag.

4. The single-line communication method according to claim 3, further comprising: The plurality of LED driving circuits acquire current-level driving data based on the interval mark in the driving data packet; or The plurality of LED driving circuits obtain current-level driving data based on the fixed length in the driving data packet.

5. The single-wire communication method according to claim 4, wherein: When the plurality of LED driving circuits acquire current-stage driving data based on the fixed length in the driving data packet, the plurality of LED driving circuits are configured such that the length of the status data packet is less than or equal to the length of the driving data packet.

6. The single-wire communication method according to claim 5, wherein: The driving data packet includes vacant data bits.

7. The single-line communication method according to claim 2 or 3, further comprising: The current-stage status data packet includes a read flag, and the plurality of LED driving circuits forward the previous-stage status data packet based on the read flag in the received status data packet.

8. The single-wire communication method according to claim 7, further comprising: The multiple LED driving circuits obtain driving data of the current stage and switch to a buffer mode. In the buffer mode, the front-stage LED driving circuit in the multiple LED driving circuits directly forwards the driving data packet of the rear-stage LED driving circuit to the rear-stage LED driving circuit.

9. The single-wire communication method according to claim 1, further comprising: The status data packets of the plurality of driving circuits are forwarded to the second data port of the controller via the second data port of the last-stage LED driving circuit among the plurality of LED driving circuits.

10. The single-wire communication method according to claim 7, wherein: The current stage status data packet includes the shift output after the LED driving circuit intercepts the current stage driving data.

11. A single-line communication device for an LED display system, comprising: A plurality of LED driving circuits, each of which comprises a first data port and a second data port, and the plurality of LED driving circuits are cascaded with each other using the first data port and the second data port, A controller, the controller comprising a first data port and a second data port, the first data port being used to provide a driving data packet, and the second data port being used to receive a status data packet; The first data port of the first-stage LED driving circuit among the plurality of LED driving circuits is connected to the first data port of the controller, and the second data port of the last-stage LED driving circuit among the plurality of LED driving circuits is connected to the second data port of the controller. The preceding LED driving circuit in the plurality of LED driving circuits forwards a preceding state data packet and a succeeding driving data packet to a succeeding LED driving circuit, The multiple LED driving circuits forward the status data packet of the current stage while acquiring the driving data of the current stage from the driving data packet.

12. The single-wire communication device according to claim 11, wherein the plurality of LED driving circuits obtain current-stage driving data from a driving data packet forwarded by a previous-stage LED driving circuit based on a separation mark or a fixed length in the driving data packet; or The multiple LED driving circuits start to obtain current-stage driving data from the driving data packet forwarded by the controller or the previous-stage LED driving circuit based on the write flag and forward the write flag.

13. The single-line communication device according to claim 11, wherein the plurality of LED driving circuits obtain driving data of the current stage and complete switching to a buffer mode, wherein in the buffer mode, a preceding LED driving circuit among the plurality of LED driving circuits directly forwards a driving data packet of the succeeding stage to a succeeding LED driving circuit.

14. An LED driving circuit for an LED display system, comprising: A first data port and a second data port are used for cascading with a plurality of LED driving circuits; A plurality of driving control units, used for connecting to a plurality of LEDs and performing driving control; A serial shift unit, used to intercept data corresponding to the LED driving circuit at this level in the driving data packet; The second data port in the LED driving circuit forwards the status data packet of the previous stage and the driving data packet of the next stage to the next stage LED driving circuit, and the first data port in the LED driving circuit is used to receive the status data packet and the driving data packet forwarded by the previous stage LED driving circuit. The plurality of LED driving circuits forward the status data packet of the current stage while acquiring the driving data of the current stage from the driving data packet.

15. The LED driving circuit according to claim 14, wherein: The LED driving circuit is configured as: The driving data of the current stage is obtained from the driving data packet forwarded by the previous stage LED driving circuit based on the separation mark or the fixed length in the driving data packet.

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