Light source driving circuit and communication device for display system

Abstract

The application discloses a light source driving circuit and a communication device for a display system. The communication device comprises a control unit and at least one light source driving circuit. The control unit comprises an output interface for sending control commands or data and an input interface for reading back data. Each light source driving circuit comprises a plurality of light source driving circuits. Each light source driving circuit interface comprises a serial input interface, a serial output interface, a parallel interface, and at least one current output interface. The serial input interfaces and the serial output interfaces of the plurality of light source driving circuits are cascaded with each other as a first channel for transmitting the control commands or the data. The parallel interfaces of each light source driving circuit in the plurality of light source driving circuits are coupled with each other as a second channel for transmitting the control commands and the data. The first channel and the second channel transmit the data simultaneously. The technical scheme of the application introduces redundant transmission channels in the display system, thereby improving the reliability of data transmission of the display system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic circuits, and more particularly, to a light source driving circuit and a communication device for a display system. BACKGROUND

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

[0003] In liquid crystal displays, liquid crystal molecules themselves do not emit light, and an array of LEDs in a backlight module (BLU) forms a surface light source to provide backlight with sufficient brightness and uniform distribution. The light-emitting 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-zone direct-type mini-LED backlight technology has been developed to achieve high brightness, high color gamut, high contrast, and energy saving for LCD display.

[0004] Current mini-LED backlight driving is gradually transferred from passive driving technology to active driving technology. The light-emitting chips of active backlight are often thousands or even hundreds of thousands, so the accuracy, precision, and speed of driving multiple mini-LEDs are very high. Therefore, it is a great challenge to achieve an LED driving system with simple interface wiring, high transmission rate, and high reliability to improve the efficiency of the backlight system. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a light source driving circuit and a communication device for a display system to solve the technical problems of low transmission rate and insufficient accuracy of backlight driving of multiple light sources.

[0006] The application provides a communication device for a display system, comprising: a control unit comprising a first output interface for sending control commands or data, and a read-back data input interface, the commands comprising at least one of configuration data packets, brightness data packets, detection data packets, address data, device address storage data packets, and read-back commands; at least one light source driving circuit, each light source driving circuit comprising a plurality of light source driving circuits, each of the light source driving circuits comprising a serial input interface, a serial output interface, a parallel interface, and at least one current output interface; the serial input interfaces and the serial output interfaces of the plurality of light source driving circuits are cascaded to each other as a first channel for transmitting the control commands or data; the parallel interfaces of each of the plurality of light source driving circuits are coupled to each other as a second channel for transmitting the control commands or data; and the control commands or data transmitted by the first channel and the second channel simultaneously are at least one of the configuration data packets, the brightness data packets, the detection data packets, and the read-back commands.

[0007] Preferably, the control unit transmits address data to a first driving circuit of the light source driving circuit through the first output interface, the first driving circuit extracts the address data required by the current stage, repackages the address data of the remaining driving circuits, and transmits the repackaged data to the next stage through the serial output interface.

[0008] Preferably, the control unit further comprises a second output interface, the control unit transmits at least one of the configuration data packets, the brightness data packets, the detection data, and the read-back commands to the first driving circuit through the first output interface, then the plurality of light source driving circuits transmit the data to the next stage through the serial input interface and the serial output interface, and the control unit transmits at least one of the configuration data packets, the brightness data packets, the detection data, and the read-back commands to the parallel interfaces of all the light source driving circuits through the second output interface.

[0009] Preferably, the control unit transmits at least one of the configuration data packets, the brightness data packets, the detection data, and the read-back commands to a first driving circuit of the light source driving circuit through the first output interface, the first driving circuit receives the control commands or data through the serial input interface, extracts the commands or data required by the current stage, repackages the commands or data of the remaining driving circuits, and transmits the repackaged data to the next stage through the serial output interface and the parallel interface of the current stage; the second and subsequent driving circuits receive the commands or data through the serial input interface and the parallel interface of the current stage, extract the commands or data required by the current stage, repackage the commands or data of the remaining driving circuits, and transmit the repackaged data to the next stage through the serial output interface and the parallel interface of the current stage.

[0010] Preferably, the light source driving circuit works in an addressing phase, a configuration phase and a light emitting phase in sequence, the control unit outputs address data in the addressing phase, outputs configuration data in the configuration phase and outputs brightness data in the light emitting phase.

[0011] Preferably, the control unit sends a device address storage command to each light source driving circuit through the output interface, and each light source driving circuit burns the assigned address data into its storage device.

[0012] Preferably, the serial input interface of the first driving circuit in each light source driving circuit is coupled to the first output interface of the control unit, the serial input interface of each remaining driving circuit is coupled to the serial output interface of the previous driving circuit, the parallel interface of each remaining driving circuit is coupled to the parallel interface of the first driving circuit, and the serial output interface of the last driving circuit in each light source driving circuit is connected to the read-back data input interface of the control unit.

[0013] Preferably, the serial input interface of the first driving circuit in each light source driving circuit is coupled to the first output interface of the control unit, the serial input interface of each remaining driving circuit is coupled to the serial output interface of the previous driving circuit, the parallel interface of each driving circuit is coupled to the second output interface of the control unit, and the serial output interface of the last driving circuit in each light source driving circuit is connected to the read-back data input interface of the control unit.

[0014] Preferably, the parallel interface of the plurality of light source driving circuits is a bidirectional tri-state port.

[0015] Preferably, when the control unit sends a read-back command to the light source driving circuit, the light source driving circuit currently receiving the read-back command determines whether to return the read-back data of the current stage to the control unit according to whether the address of the current stage is consistent with the device address of the required returned data in the read-back command.

[0016] The plurality of light source driving circuits transmit the status data to be read back to the last light source driving circuit via the data communication line formed by the serial input interface and the serial output interface of the light source driving circuit and / or the data communication line formed by the parallel interface of the light source driving circuit, and the last light source driving circuit returns the read-back data of all light source driving circuits to the read-back data input interface of the control unit.

[0017] Preferably, the control unit sends a first detection command to the first driving circuit through the output interface, and the first driving circuit forwards the first detection command to the parallel interface of the current stage, or pulls down the signal of the parallel interface for a period of time, and the remaining driving circuits receive the first detection command or detect the pull-down of the signal of the parallel interface through the parallel interface of the current stage. All driving circuits in each channel call out configuration parameters corresponding to the first detection command, and light up the LED lamps electrically connected to the current output interface of the driving circuit to perform circuit detection.

[0018] Preferably, the control unit sends a second detection command to the first driving circuit through the output interface, and the first driving circuit forwards the second detection command to the serial output interface of the current stage, and the remaining driving circuits receive the second detection command through the serial input interface of the current stage. All driving circuits in each channel call out configuration parameters corresponding to the second detection command, and light up the LED lamps electrically connected to the current output interface of the driving circuit to perform circuit detection.

[0019] Preferably, the display system includes any one of a liquid crystal display screen using LEDs to provide backlight and an LED display screen using LEDs as pixel units.

[0020] The application provides a light source driving circuit for a display system, comprising: a plurality of light source driving circuits cascaded with each other to form a light source driving circuit, each light source driving circuit comprising a serial input interface, a serial output interface, a parallel interface, and at least one current output interface, the current output interface being connected to a plurality of LED lamps to provide driving current for the LED lamps, the serial input interfaces and the serial output interfaces of the plurality of light source driving circuits being cascaded with each other as a first channel for transmission of control commands or data, the parallel interfaces of each driving circuit in the plurality of driving circuits being coupled together as a second channel for transmission of control commands and data, wherein the commands and data transmitted simultaneously by the first channel and the second channel are at least one of configuration data packets, brightness data packets, detection data packets, and read-back commands.

[0021] Preferably, the serial input interface of the first driving circuit in each light source driving circuit is used to receive commands or data of a control unit, extract address data required by the current stage, and then repackage commands or data of the remaining driving circuits, and the first driving circuit transmits the repackaged data packets through the serial output interface and the parallel interface of the current stage at the same time.

[0022] Preferably, the serial input interface of the first one of the light source driving circuits is used to receive the commands or data from the control unit, to take out the address data needed by the current stage, and then to repackage the commands or data of the remaining driving circuits, and the first one of the light source driving circuits transmits the repackaged data packets out through the serial output interface of the current stage, and the parallel interface of all the driving circuits in each light source driving circuit is used to receive the commands or data.

[0023] Preferably, the serial input interface of the first one of the light source driving circuits is coupled to the first output interface of the control unit, the serial input interface of each of the remaining driving circuits is coupled to the serial output interface of the previous driving circuit, and the parallel interface of each of the remaining driving circuits is coupled to the parallel interface of the first one of the light source driving circuits, and the serial output interface of the last one of the light source driving circuits is coupled to the read-back data input interface of the control unit for the return output of the read-back data.

[0024] Preferably, the serial input interface of the first one of the light source driving circuits is coupled to the first output interface of the control unit, the serial input interface of each of the remaining driving circuits is coupled to the serial output interface of the previous driving circuit, and the parallel interface of each of the remaining driving circuits is coupled to the second output interface of the control unit, and the serial output interface of the last one of the light source driving circuits is coupled to the read-back data input interface of the control unit for the return output of the read-back data.

[0025] Preferably, the light source driving circuit receives the transmitted packaged data packets through the serial input interface and the parallel interface, takes out the commands or data belonging to the current stage according to the address of the current stage, and then repackages the subsequent commands or data, and monitors the data of the serial output interface and the parallel interface of the current stage to transmit the repackaged new data packets through the serial output interface and the parallel interface at the same time.

[0026] Preferably, the light source driving circuit receives the repackaged data packets through the serial input interface and the parallel interface, the light source driving circuit selects the data packet that reaches the two interfaces first, takes out the commands or data belonging to the current stage according to the address of the current stage, and then repackages the subsequent commands or data, and monitors the data of the serial output interface and the parallel interface of the current stage to transmit the repackaged new data packets through the serial output interface and the parallel interface at the same time.

[0027] Preferably, the first one of the light source driving circuits receives the address data, the first one of the light source driving circuits takes out the address data needed by the current stage, and then repackages the address data of the remaining driving circuits, and transmits the repackaged data packets out through the serial output interface, and the light source driving circuits of the subsequent stages transmit the address data in turn.

[0028] Preferably, each driving circuit has a non-volatile memory for storing address data of the driving circuit.

[0029] Preferably, each light source driving circuit generates the address data packet of the next stage light source driving circuit after intercepting the address of the current stage light source driving circuit from the address data packet provided by the control unit, or performs addition or subtraction operation on the effective address data of the current stage light source driving circuit to obtain the address data packet of the next stage light source driving circuit.

[0030] The present application improves the speed and reliability of data transmission of the light source driving system by introducing parallel data transmission at the driving circuit and using redundant transmission channels, thereby greatly reducing the adverse effects of faults in the product life cycle on the light source driving system. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the provided drawings.

[0032] Figure 1 A schematic diagram of a backlight module according to the present application;

[0033] Figure 2 A structural schematic diagram of a first embodiment of a communication device of a display system according to the present application;

[0034] Figure 3 A schematic diagram of a first address addressing according to the addressing mode of the present application;

[0035] Figure 4 A schematic diagram of configuration and data receiving process according to the present application;

[0036] Figure 5 A schematic diagram of DET1 command process according to the present application;

[0037] Figure 6 A schematic diagram of DET2 command process according to the present application;

[0038] Figure 7 A structural schematic diagram of a second embodiment of a communication device of a display system according to the present application. DETAILED DESCRIPTION

[0039] The present application is described in detail below based on examples, but the present application is not limited to these examples. In the following detailed description of the present application, some specific details are described in detail. The present application can also be fully understood without the description of these details by those skilled in the art. In order to avoid confusion of the essence of the present application, well-known methods, processes, procedures, elements and circuits are not described in detail.

[0040] 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 sub-circuit through electrical or electromagnetic connection. When an element or circuit is said to be "connected to" another element or said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be intermediate elements, and the connection between 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.

[0041] Unless the context clearly requires otherwise, throughout the description and the claims, "comprise", "comprise", and similar words such as "comprise" should be interpreted as inclusive rather than exclusive or exhaustive; that is, as "including but not limited to".

[0042] In the description herein, it is to be understood that the terms "first", "second", and the like are used only for descriptive purposes and are not to be construed as indicating or implying relative importance. In addition, in the description herein, unless otherwise stated, the meaning of "multiple" is two or more.

[0043] In the description herein, the terms "first LED drive circuit" and "last LED drive circuit", as well as "input port" and "output port", are defined according to the connection relationship between the LED drive circuit and the output port SDO of the control unit. Among them, the first LED drive circuit is not limited to the first column of LED drive circuits in a string, but can also be the first allocated address LED drive circuit in a string.

[0044] Figure 1 For the schematic diagram of the backlight module according to the present application, the backlight module includes a control unit, a plurality of light source drive circuits, and a plurality of light source blocks corresponding to the plurality of light source drive circuits. Here, LEDs are used as light sources for illustration, but the light sources are not limited thereto.

[0045] As the backlight module is a liquid crystal display screen, the liquid crystal panel includes a TFT array substrate, a color filter, and a liquid crystal layer sandwiched between the two, and the TFT array substrate is used to control the transmittance of the liquid crystal layer. The backlight module is located below the array substrate and provides backlight as a light source, and after passing through the liquid crystal panel, the luminous brightness corresponding to the pixel gray scale can be obtained. In this embodiment, a plurality of light source blocks each include a plurality of LED light sources arranged in an array, and the LED blocks themselves are also arranged in an array according to certain rules, so that a surface light source is formed by a plurality of point light sources.

[0046] In the display mode of the backlight module, the luminance data of the light source is output via the control unit. The plurality of current driving ends (such as CH1 to CHn) of the plurality of light source driving circuits respectively apply a constant current to the light source connected thereto. According to the luminance data of the light source, the current of the current driving end of the light source driving circuit is adjusted in duty cycle or amplitude, and the equivalent current size of the plurality of light sources on the current light source string can be changed, so as to adjust the backlight brightness in zones.

[0047] The row driver is used to drive whether the light source of each row receives the power voltage to emit light.

[0048] Reference Figure 2 The structural schematic diagram of the embodiment of the communication device of the display system according to the present application includes a backlight control unit TX, a light source driving circuit Rx, an LED array driving circuit Rx in this embodiment, a serial communication line SDI-SDO, a parallel communication line PIO, a mini-LED array unit MLED, and a power supply line VAA of the common anode of the mini-LED. Here, the LED array driving circuit includes multiple paths, and each path of the LED array driving circuit includes a plurality of LED driving circuits. RxN represents the Nth LED driving circuit in a certain path of the LED array driving circuit. The ground line of the LED array driving circuit Rx is not shown.

[0049] Further, the backlight control unit TX comprises at least: a data communication interface SPI and an interactive signal interface ctrl connected with the front-stage image processing engine module SOC, an output interface SDOx (x = 1, 2,..., m) of control commands or data commands electrically connected with the rear-stage LED array driving circuit, and a back-reading data input interface SDIx (x = 1, 2,..., m), m being any natural number. At least one data communication interface SPI is connected to the data communication interface SPI of the front-stage engine module SOC, and at least one interactive signal interface ctrl is connected to the ctrl signal interface of the front-stage engine module SOC, so as to complete the information data interaction with the front-stage SOC through the two signal interfaces. In the backlight module, the commands output by the control unit comprise at least one of brightness data, configuration data, address data, detection data, device address storage data packet, back-reading command data packet, and enable signal. In the display system, the commands output by the control unit comprise at least one of gray scale data, configuration data, address data, detection data, device address storage data packet, back-reading command data packet, and enable signal.

[0050] As shown in Figure 2 , each SDO interface in the backlight control unit Tx is connected to the SDI interface of the first driving circuit Rx1 in a path, and the so-called "path" refers to the collection of a plurality of LED driving circuits Rx which are serially connected in a group through the SDI-SDO serial communication line. The LED driving system can be composed of at least one path, and the number of driving circuits serially connected in a path is at least one. Further, for each LED driving circuit Rx, it comprises at least: a data input interface SDI, a data output interface SDO, a data transmission interface PIO, at least one current output channel CH Figure 2 , the example channels are 4, CH1, CH2, CH3, CH4), a chip power supply interface and a reference ground interface (not shown in the figure).

[0051] Preferably, the plurality of LED driving circuits are cascaded with each other to provide a serial communication bus SDI-SDO. In physical connection, the serial communication bus SDI-SDO can be only one single-ended signal data line, in which case the data transmission is completed through the embedded clock technology; or can be 2 or more single-ended signal lines, one of which is called a clock line, and the other 1 or more are called data lines, which cooperate with each other to complete data transmission; or can be 2 differential signal lines, in which case the super-high-speed data transmission is completed through the embedded clock technology, which can reduce EMI.

[0052] Preferably, the PIO ports of the plurality of LED driving circuits are connected with each other to form a parallel communication line PIO, which is a bidirectional tri-state port in physical connection.

[0053] With reference to Figure 2, except the first driving circuit, the SDI interface of each remaining driving circuit Rx is connected to the SDO interface of the previous driving circuit Rx, and the SDI interface of the first driving circuit is connected to the SDO interface of the backlight control unit Tx; the SDO interface of each driving circuit Rx is connected to the SDI interface of the next driving circuit Rx, and the SDO interface of the last driving circuit Rx is optionally connected to the SDI interface of the backlight control unit Tx, and the PIO ports of all driving circuits Rx of each channel are connected in parallel. It should be noted that the SDI port and the SDO port of the LED driving circuit can be configured as one of an input port, an output port and a tri-state port according to the direction of data flow. The current output channel CH is independently connected to the cathode of the respective light-emitting unit mini-LED array, the anode of the mini-LED array in a string is connected together, and is connected to the power supply VAA_x (x = 1, 2,..., m). The anode power supply of the mini-LED can be connected together, or the anode power supply of each string can be independently powered, or the anodes of some 2 or more strings can be connected together.

[0054] It should be noted that the image processing engine module SOC is the data source of the mini-LED backlight system and does not belong to the driving system of the present application, and is only used for description and principle explanation. The control unit can be connected to the previous image processing engine SOC via a communication bus (SPI, LVDS or VBYONE) to receive image data or brightness data.

[0055] In one example, after the system is powered on, the control unit Tx XAnd the LED drive circuit is reset, and the front-stage image processing engine SOC controls the unit Tx to perform power-on initialization action according to the set power-on sequence. After the unit Tx completes the initialization of the backlight system, the engine control module SOC sends the backlight data such as brightness data to the data communication interface SPI of the unit Tx through the first output port SPI. After the unit Tx receives the brightness data and processes it, the unit Tx transmits the brightness data to the first LED drive circuit Rx of a certain path. The first LED drive circuit Rx obtains the brightness data of the current stage and converts the brightness data into a corresponding current size to drive the corresponding mini-LED light emitting device to emit light. For example, the current of the current driving end of the LED drive circuit is adjusted in duty cycle or amplitude according to the brightness data of the LED, so as to change the equivalent current size of the plurality of LEDs on the current LED string, thereby adjusting the backlight brightness in zones. Moreover, the first LED drive circuit intercepts the brightness data of the current stage, repackages the intercepted brightness data, and transmits the processed data packet to the remaining drive circuits Rx of the path. After receiving the data packet, the remaining LED drive circuits Rx read the brightness data and convert the brightness data into a corresponding current size to drive the corresponding mini-LED light emitting device to emit light, thereby displaying the corresponding data (image) on the backlight array. In particular, the engine control module SOC can also perform online upgrade function on the backlight control unit Tx through the first output port SPI to automatically upgrade the function of the unit Tx after leaving the factory, thereby improving the user experience. The above takes the brightness data as an example. In the display system of the present application, other data such as configuration data and detection data sent by the unit Tx are first transmitted to the first drive circuit and then transmitted to the rear-stage drive circuit by the first drive circuit.

[0056] For example, after the power-on reset (POR), the unit TX first performs address allocation (corresponding to address data) on the LED array drive circuit Rx according to the set power-on sequence, then performs working parameter configuration (corresponding to configuration data) on the array drive circuit Rx, and finally sends the backlight data received by the data communication interface SPI to the drive circuit (corresponding to display data or brightness data), thereby controlling the current size of the output current channel of the drive circuit Rx to complete the controlled processing of the mini-LED light emitting diode connected to each current channel of the entire backlight system. According to the above control process, the communication device of the display system can be divided into three stages: addressing stage, configuration stage and light emitting stage.

[0057] In one example, in the addressing stage, the control unit Tx sends an addressing data packet to the plurality of drive circuits Rx through the output port SDO, and assigns addresses to the plurality of drive circuits Rx, the addressing data packet at least including address data of the current drive circuit Rx. Each drive circuit Rx takes the corresponding address data in the received addressing data packet as the address of the current drive circuit Rx, and then increases or decreases the current address by a fixed constant value (usually by 1, or any natural number) to obtain the address of the next receiving drive circuit Rx, and finally forms a new address data packet and sends it out through the data output interface SDO of the current level.

[0058] For example, referring to FIG. 1, Figure 3 The addressing mode implementation process can include the following steps:

[0059] 1) The control unit Tx first sends an addressing data packet containing only the address of the drive circuit Rx connected to the control unit Tx to the SDO output interface.

[0060] 2) The first drive circuit Rx connects to the SDO interface through the SDI interface to receive the addressing data packet. The data from the SDI interface is analyzed according to the following rules:

[0061] The addressing data packet from the SDI interface is parsed according to the address data packet parsing rules, the address data of the current level is intercepted and stored in the address register of the current drive circuit, and then the received payload address data is increased or decreased by a fixed constant value (usually by 1, or any natural number) to form a new address packet, and the recombined new address data packet is sent out through the SDO interface of the current level;

[0062] The address data packet includes a preamble field, a payload, and a frame check sum CRC, the preamble field includes a synchronization marker SYNC and a frame start delimiter SFD, the payload includes a command type CMD, a data length LENGTH, and a payload address data AD. The re-packing of the address data packet includes, for example, an accumulation operation or a subtraction operation on the payload address data AD of the current address to obtain the address of the next level, for example, the increment of the accumulation operation or the decrement of the subtraction operation is 1 or any natural number, such as Figure 2 SDO_Rx1 is AD+1, SDO_Rx2 is AD+2, and so on, and the preamble field and the address data of the next level in the address data packet are re-packed into a new address data packet.

[0063] Each drive circuit Rx re-packs and forwards the address data packet from the SDI according to the above rules to the SDO interface of the current level for transmission to the next level of LED drive circuit.

[0064] 3) so on, until the last driving circuit Rx, which also takes its own address data according to the rule of step 2), to complete the allocation of the address of each driving circuit Rx.

[0065] In addition to the above description, the addressing mode can also have the following two forms, and the transmission mode is similar to the process and the description of steps 2) and 3) above.

[0066] As the second addressing mode: the control unit Tx pulls down or pulls up the signal of SDO for a period of time as an addressing start signal to the first driving circuit Rx electrically connected to the SDO interface of the control unit Tx. After receiving the addressing start signal, the driving circuit Rx fixes its own address to a certain fixed value, and the data rule of the address data packet is the same as that of the first embodiment. Then, the driving circuit Rx re-packs the payload address data AD and outputs the address of the next level LED driving circuit through the SDO interface of the driving circuit Rx at this level. In this way, the address of the last driving circuit Rx at this level is allocated.

[0067] Or the third addressing mode: the control unit Tx sends an addressing packet containing the addresses of all driving circuits Rx through the SDO interface. The first driving circuit Rx connected to the control unit Tx intercepts the data at a fixed position as the address at this level, and then re-packs all the addresses of the subsequent driving circuits Rx and outputs them to the next level through the SDO interface. Each subsequent driving circuit Rx receives the data packet through the SDI interface, intercepts the data at a fixed position as the address at this level, and then re-packs all the addresses of the subsequent driving circuits Rx and outputs them to the next level through the SDO interface. The re-packing of the address data packet, for example, includes obtaining the payload address data at this level from the address data packet, and re-packing the leading field in the address data packet and the address data at the next level into a new address data packet.

[0068] After the addressing phase, the configuration phase is entered.

[0069] In the configuration phase, the control unit Tx generates a series of control commands and sends them to each driving circuit Rx through the SDO interface to configure the working parameters of each driving circuit Rx. The control command can be a configuration data sending command (including a configuration data packet). The flowchart is shown in Figure 3 The configuration process in the embodiment of the application is described as follows:

[0070] 1) After the control unit Tx and the driving circuit Rx are powered on and reset, Figure 4In step S1, the control unit Tx first sends a data packet containing the configuration of all the drive circuits Rx to the SDO bus. The configuration data packet includes a preamble field, a payload and a frame check sum CRC, the preamble field includes a synchronization marker SYNC, a frame start delimiter SFD, the payload includes an instruction type CMD, a data length LENGTH and a chip operating parameter configuration value.

[0071] 2) The first LED drive circuit receives the configuration data packet from the previous stage control unit only through the data input interface SDI, but this is a case of the data receiving behavior of the LED drive circuit, so the data packet processing flow of the LED drive circuit can be normalized, Figure 4 In step S2, the normalized processing flow is as shown in step 3).

[0072] 3) Each drive circuit Rx can receive the configuration data packet through the SDI interface and the PIO interface of the current stage, and parse the data packet from the two interfaces according to the following rules:

[0073] The LED drive circuit RX monitors the data status of the PIO and SDI ports of the current stage,

[0074] The data packet from the SDI interface is taken out according to the configuration data of the current stage, and the subsequent configuration data is repackaged. It is checked whether there is data transmission on the SDO interface of the current stage, if yes, no operation is performed on the SDO. If not, it is checked whether there is data input on the PIO interface of the current stage at this time, if not, the new data packet is sent out through the SDO interface and the PIO interface. If there is data input on the PIO interface, no operation is performed on the PIO interface, and the new data packet is sent out through the SDO interface.

[0075] The data packet from the PIO interface is taken out according to the configuration data of the current stage, and the subsequent configuration data is repackaged. It is checked whether there is data transmission on the SDO interface at this time, if not, the repackaged configuration data is sent out through the SDO interface. If the SDO interface is transmitting data, no operation is performed on the SDO interface.

[0076] In this way, the configuration data packets from the SDI interface and the PIO interface are reforwarded to the SDO interface and / or the PIO interface according to the above rules for transmission to the next stage. Figure 3 In steps S3-S4.

[0077] 4) This cycle continues until the last drive circuit Rx takes out the configuration data of the current stage according to the rule of step 3). Figure 4 In step S5.

[0078] Thus, in addition to the first drive circuit, the configuration data of each drive circuit Rx will have 2 link inputs, 2-way data output, that is, PIO interface input and SDI interface input, after being processed by the drive circuit Rx, from the SDO interface output and PIO interface output. Ensures that the configuration data will not be damaged due to PIO link or SDI link, and thus the drive circuit Rx is not controlled, thereby improving the reliability of the received data of the drive circuit Rx.

[0079] This configuration method ensures the speed and reliability of data transmission through concurrent transmission and redundant transmission of drive circuit Rx data. For the above-mentioned redundant transmission method, it can also be applied to other display systems, not limited to the LED drive system architecture of the embodiment, as long as the two-way input and output architecture of the configuration data signal can be used, such as the control unit sending configuration data to each drive circuit through a concurrent data interface, and each drive circuit obtaining double-link transmission of configuration data through SDI-SDO link and PIO concurrent link. The data double-link transmission of the application is within the protection scope of the application.

[0080] In the configuration phase, the second and subsequent light source drive circuits can also process the received data as follows:

[0081] The second and subsequent LED drive circuits in each LED drive circuit receive the repackaged data packets through the serial input interface and the parallel interface. The LED drive circuit selects the data packet that reaches the interface first, that is, if the data packet that reaches the serial input interface first, the data packet that reaches the parallel interface is not received or is shielded. If the data packet that reaches the parallel interface first, the data packet that reaches the serial input interface is not received or is shielded.

[0082] Then, according to the address of the current level, the command or data belonging to the current level is taken out, and the subsequent command or data is repackaged. The data of the serial output interface and the parallel interface of the current level is monitored to send the repackaged new data packet through the serial output interface and the parallel interface at the same time. The forwarding method is the same as steps 1-4 of the above embodiment.

[0083] After the configuration is completed, the light emitting phase is entered:

[0084] In the light-emitting stage, the driving circuit Rx converts the received backlight display data such as luminance data into corresponding current sizes according to the received backlight display data, and outputs the current sizes to corresponding current channels to control the light-emission of the mini-LED. The transmission and processing process of the luminance data is consistent with that in the configuration stage, and is transmitted through the dual-link transmission, which will not be repeated here. Similarly, the luminance data transmitted through the dual-link transmission ensures that the luminance data cannot be damaged by the PIO link or the SDI link, thereby improving the reliability of the received data of the driving circuit Rx.

[0085] Further, the backlight control unit Tx can also issue a read-back command through the interface SDO to obtain the state information (such as the open / short state of the driving circuit Rx, temperature information, etc.) of a certain driving circuit on the corresponding road. The control unit Tx issues the read-back command through the output interface SDOx (x = 1, 2, m) of the serial bus, and the transmission process of the read-back command is the same as that of the configuration data transmission process, so that each driving circuit Rx can obtain the read-back command through the dual-link, and the driving circuit Rx generates read-back data according to the read-back command. The read-back data is returned to the SDO port of the control unit Tx through the serial communication bus SDO-SDI of the driving circuit Rx or the read-back data is returned to the last driving circuit RxN through the parallel communication bus PIO in time division multiplexing. The time division multiplexing can be understood as transmitting the display data command and the read-back command at different times. Finally, the driving circuit RxN receives through the PIO, and then returns the read-back data to the SDO interface of the control unit Tx through the SDO interface thereof, or the read-back data is transmitted reversely to the SDO port of the control unit Tx through the SDO-SDI bus of the driving circuit Rx (at this time, the SDI and SDO ports are bidirectional ports).

[0086] One implementation of the read-back is as follows:

[0087] 1) After the control unit Tx and the driving circuit Rx are powered on and reset, the control unit Tx sends a data packet containing a read-back command to the serial bus SDO, and the data packet at least has: the device address start_id of the driving circuit Rx which needs to return data, whether it is the last level driving circuit Rx to return data, and the address of the returned data.

[0088] 2) The driving circuit Rx receives the read-back command data, and the transmission mode of the read-back command data packet is the same as that of the configuration data command transmission mode, that is, each driving circuit obtains the dual-link transmission of the configuration data through the SDO-SDI link and the PIO concurrent link, which will not be repeated here.

[0089] 3) Through the process of step 2), all driving circuits Rx obtain the read-back control word in the read-back command data packet.

[0090] 4) Each of the LED driving circuits determines whether to return the read-back data of the current stage to the control unit according to whether the address of the current stage is consistent with the device address requiring to return data in the read-back command,

[0091] The plurality of LED driving circuits transmit the read-back state data to the last LED driving circuit via a data communication line composed of the serial input interface and the serial output interface of the LED driving circuit and / or a data communication line composed of a parallel interface of the LED driving circuit,

[0092] The serial output interface of the last driving circuit of each LED driving circuit returns the read-back data of all the LED driving circuits of the route.

[0093] Thus, the control unit Tx transmits the read-back data corresponding to the address of the read-back command to the last stage driving circuit RxN through the SDI-SDO link or / and directly to the driving circuit RxN through the PIO link.

[0094] 5) After receiving the read-back command, the last stage driving circuit RxN pulls up the data flag signal rb_ind to be returned to the active state, and after receiving the read-back data packet, the last stage driving circuit RxN sends the read-back data packet to the SDO port, and changes the rb_ind signal to be invalid, and ignores the subsequent received read-back data packet.

[0095] The read-back data packet is sent to the SDO port of the control unit Tx through the SDO port of the driving circuit RxN, and the control unit Tx parses the read-back data packet to complete the acquisition of the read-back information.

[0096] Further, in order to facilitate the confirmation of the defects of each driving circuit Rx and other peripheral interconnection devices in the production process, and quickly pick out the defective points, thereby accelerating the modification process, the application proposes a detection scheme. The control unit Tx only needs to send the DET1 lighting command once to complete the bad point detection on the backlight system, and can distinguish whether the defective problem is caused by the driving circuit Rx or the surrounding device, so as to facilitate the quick solution of the problem. The flow chart is as shown in Figure 5 The process is described as follows:

[0097] 1) The control unit Tx sends a data packet of the DET1 lighting command containing only the control data of the driving circuit Rx1 to the serial communication bus SDO.

[0098] 2) The first driving circuit Rx electrically connected to the control unit Tx only forwards the DET1 command to the PIO interface of the current stage, or directly pulls down the signal of the PIO interface for a period of time, and no longer forwards it to the SDO interface.

[0099] 3) Each drive circuit Rx receives DET1 command or detects that the PIO interface signal is pulled low for a period of time, and the drive circuit Rx calls out the configuration parameters corresponding to the DET1 command, wherein the configuration parameters corresponding to the DET1 command can be transmitted by the control unit Tx to each drive circuit in the configuration stage, and the current channel of the drive circuit Rx is electrically connected to the LED lamp bead which is actively lit.

[0100] 4) If the drive circuit Rx and the surrounding electrical connection are good, DET1 can light up all the LED lamps. If one or more LED lamps are not lit, the position is recorded, and DET1 completes the determination of the position of the non-lit LED.

[0101] This step can preliminarily determine whether the non-lit LED belongs to the same drive circuit Rx, and whether the problem is with the drive circuit Rx or the surrounding device:

[0102] If the LED lamps belonging to the same drive circuit Rx have some that are lit and some that are not lit, it can be determined that the problem is with the surrounding device.

[0103] If all the LED lamps belonging to the same drive circuit Rx are not lit, it can be determined that the problem is with the link channel of the PIO or the drive circuit Rx, and DET2 command is needed to determine whether the problem is with the drive circuit Rx or the surrounding device.

[0104] The control unit sends the DET2 command again, enters the next step of detection, and the flow chart is as shown in Figure 6 , and the process is as follows:

[0105] 5) The control unit Tx sends a data packet including the DET2 lighting command to the serial bus SDO.

[0106] 6) After the drive circuit Rx receives the DET2 data packet through the SDI interface, it only transfers the DET2 command to the SDO interface, and no longer forwards it to the PIO interface. This level calls out the corresponding default parameters according to the DET2 command to light up.

[0107] 7) In this way, whether the next level drive circuit Rx of the bad point can be lit or not can be determined to determine whether the bad point is a drive circuit Rx or a surrounding device. If the next level drive circuit Rx can light up some lamps, it is a surrounding device problem, and if the previous level drive circuit Rx can light up the lamps and the next level drive circuit Rx cannot light up, it is a drive circuit Rx problem.

[0108] Further, reference is made to Figure 7For the communication device according to the second embodiment of the present application, each driving circuit includes a non-volatile storage device (NVM), when the LED driving system completes the respective link and function confirmation to be correct in the initial production stage, the control unit Tx can send a device address storage command to each driving circuit Rx, each driving circuit unit Rx obtains the address data of the current stage, and then burns the address of the current LED driving circuit into the non-volatile storage device (NVM, Non-Volatile Memory), thereby completing the solidification of the address of each driving circuit, and the address storage command data packet transmission mode sent by the control unit Tx to each driving circuit and the above-mentioned configuration data command can be the same, which will not be repeated here.

[0109] In this way, each driving circuit stores the address of the device itself, and in the subsequent configuration data and brightness data transmission process, the redundant transmission of data is completed through the above-mentioned SDI-SDO link and PIO link transmission. In the later stage of the embodiment, the serial input and serial output bus can also be damaged, and the device address of the driving circuit can be ensured to be unique and reliable. The data packet of the subsequent link redundant transmission and parallel transmission is not affected by the faulty driving circuit, and each driving circuit can independently complete the transmission of the configuration data and the brightness data, realize the light emitting function, and can conveniently detect the faulty driving circuit.

[0110] As can be known by those skilled in the art, when the LED driving system is used for the first time, the address of the current LED driving circuit can be fixed to the non-volatile storage device (NVM, Non-Volatile Memory) after the respective link and function confirmation is completed, and the solidification of the device address is completed. After that, the configuration data and the display data are transmitted and used according to the solidified address.

[0111] Through the embodiments of the present application, in the addressing stage, the configuration stage or the display stage, if the SDI input or the PIO input of a certain driving circuit Rx fails, because of the redundant transmission of the link and the storage of the device address, the corresponding data packet can be received through at least one of the PIO or the SDI, ensuring the reliable transmission of the data, so that the configuration data or the display data can be successfully transmitted according to the configuration mode of the present application. The present application introduces the redundant transmission channel and the device address storage function at the driving circuit, thereby improving the data transmission reliability of the LED driving system, and greatly reducing the adverse effects of the late-stage failure on the LED driving system in the product life cycle.

[0112] The above only describes the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A communication device for display system, comprising: a control unit including a first output interface for sending control commands or data, and a read-back data input interface, the commands including at least one of configuration data packet, brightness data packet, detection data packet, address data, device address storage data packet, read-back command, at least one light source driving circuit, each of the light source driving circuits including a serial input interface, a serial output interface, a parallel interface, and at least one current output interface, the serial input interface and the serial output interface of the plurality of light source driving circuits are cascaded to each other as a first channel for transmitting the control commands or data, and the parallel interfaces of each of the plurality of driving circuits are coupled to each other as a second channel for transmitting the control commands or data, wherein the commands and data transmitted simultaneously by the first channel and the second channel are at least one of configuration data packet, brightness data packet, detection data packet, and read-back command, wherein the light source driving circuit receives data packets through the serial input interface and the parallel interface, and the light source driving circuit selects the data packet arrived first.

2. The communication device for display system according to claim 1, wherein the control unit transmits address data to a first driving circuit of one light source driving circuit through the first output interface thereof, the first driving circuit takes out the address data required by the current stage, and then repackages the address data of the remaining driving circuits, and transmits the repackaged data packet through the serial output interface, and the light source driving circuits of the subsequent stages transmit the address data in turn.

3. The communication device for a display system of claim 2, wherein, the control unit further includes a second output interface, the control unit transmits at least one of configuration data packet, brightness data packet, detection data, and read-back command to the first driving circuit through the first output interface thereof, and then the plurality of light source driving circuits transmit in turn through the data transmission channel composed of the serial input interface and the serial output interface, and the control unit transmits at least one of configuration data packet, brightness data packet, detection data, and read-back command to the parallel interfaces of all the light source driving circuits through the second output interface thereof.

4. The communication device for display system according to claim 1, wherein the control unit transmits at least one of configuration data packet, brightness data packet, detection data, and read-back command to a first driving circuit of one light source driving circuit through the first output interface thereof, the first driving circuit receives the control commands or data through the serial input interface, takes out the commands or data required by the current stage, then repackages the commands or data of the remaining driving circuits, and transmits the repackaged data packet through the serial output interface and the parallel interface of the current stage, the second and subsequent driving circuits receive the commands or data through the serial input interface and the parallel interface of the current stage, take out the commands or data required by the current stage, then repackages the commands or data of the remaining driving circuits, and transmits the repackaged data packet through the serial output interface and the parallel interface of the current stage.

5. The communication device for display system according to claim 1, wherein, the light source driving circuit works in the addressing phase, the configuration phase and the light emitting phase in turn, the control unit outputs address data in the addressing phase, outputs configuration data in the configuration phase and outputs brightness data in the light emitting phase.

6. The communication device for display system according to claim 2, wherein, the control unit sends a device address storage command to each light source driving circuit through the output interface, and each light source driving circuit burns the assigned address data into its storage device.

7. The communication device for display system according to claim 3, wherein, the serial input interface of the first driving circuit in each light source driving circuit is coupled to the first output interface of the control unit, the serial input interface of each remaining driving circuit is coupled to the serial output interface of the previous driving circuit, and the parallel interface of each remaining driving circuit is coupled to the parallel interface of the first driving circuit, the serial output interface of the last driving circuit in each light source driving circuit is connected to the read-back data input interface of the control unit.

8. The communication device for display system according to claim 4, wherein, the serial input interface of the first driving circuit in each light source driving circuit is coupled to the first output interface of the control unit, and the serial input interface of each remaining driving circuit is coupled to the serial output interface of the previous driving circuit, the parallel interface of each driving circuit is coupled to the second output interface of the control unit, the serial output interface of the last driving circuit in each light source driving circuit is connected to the read-back data input interface of the control unit.

9. The communication device for a display system according to claim 3 or 4, wherein, the parallel interface of the plurality of light source driving circuits is a bidirectional tri-state port.

10. The communication device for display system according to claim 3 or 4, wherein, when the control unit sends a read-back command to the light source driving circuit, the light source driving circuit currently receiving the read-back command determines whether to return the read-back data of the current stage to the control unit according to whether the address of the current stage is consistent with the device address of the required returned data in the read-back command, the plurality of light source driving circuits transmit the status data required to be read back to the last light source driving circuit via the data communication line formed by the serial input interface and the serial output interface of the light source driving circuit and the data communication line formed by the parallel interface of the light source driving circuit, the last light source driving circuit returns the read-back data of all light source driving circuits to the read-back data input interface of the control unit.

11. The communication device for a display system of claim 1, wherein, the control unit sends a first detection command to the first driving circuit through the output interface, and the first driving circuit forwards the first detection command to the parallel interface of the current stage or pulls down the signal of the parallel interface for a period of time, each remaining driving circuit receives the first detection command through the parallel interface of the current stage or detects that the signal of the parallel interface is pulled down for a period of time, all driving circuits in each light source driving circuit call out the configuration parameters corresponding to the first detection command and light up the LED lamp electrically connected to the current output interface of the driving circuit to perform circuit detection.

12. The communication device for display system according to claim 1 or 11, wherein, the control unit sends a second detection command to the first driving circuit through the output interface, and the first driving circuit forwards the second detection command to the serial output interface of the current stage, each of the remaining driving circuits receives the second detection command through the serial input interface of the current stage, all the driving circuits in each channel call the configuration parameters corresponding to the second detection command, and light up the LED lamps electrically connected to the current output interface of the driving circuit to perform the detection of the circuit.

13. The communication device for a display system of claim 1, wherein, The display system includes any one of a liquid crystal display screen using LEDs to provide backlight and an LED display screen using LEDs as pixel units.

14. A light source drive circuit for a display system, comprising: The plurality of light source driving circuits are cascaded with each other to form a light source driving circuit, each of which includes a serial input interface, a serial output interface, a parallel interface, and at least one current output interface, the current output interface is connected to a plurality of LED lamps to provide driving current for the LED lamps, the serial input interfaces and the serial output interfaces of the plurality of light source driving circuits are cascaded with each other as a first channel for transmission of control commands or data, and the parallel interfaces of each of the plurality of driving circuits are coupled together as a second channel for transmission of control commands and data, wherein the commands and data transmitted simultaneously by the first channel and the second channel are at least one of a configuration data packet, a brightness data packet, a detection data packet, and a read-back command, wherein the light source driving circuit receives data packets through the serial input interface and the parallel interface, and the light source driving circuit selects the data packet that reaches first.

15. The light source driving circuit according to claim 14, wherein, the serial input interface of the first driving circuit in each of the plurality of light source driving circuits is configured to receive commands or data from the control unit, extract address data required by the current stage, and then repackage commands or data of the remaining driving circuits, the first driving circuit transmits the repackaged data packet through the serial output interface and the parallel interface of the current stage.

16. The light source driving circuit according to claim 15, wherein the serial input interface of the first driving circuit in each of the plurality of light source driving circuits is configured to receive commands or data from the control unit, extract address data required by the current stage, and then repackage commands or data of the remaining driving circuits, and the first driving circuit transmits the repackaged data packet through the serial output interface of the current stage, and the parallel interfaces of all the driving circuits in each of the plurality of light source driving circuits are configured to receive the commands or data.

17. The light source driving circuit according to claim 15, wherein, the serial input interface of the first driving circuit in each of the plurality of light source driving circuits is coupled to a first output interface of the control unit, and the serial input interface of each of the remaining driving circuits is coupled to the serial output interface of the previous driving circuit, and the parallel interfaces of each of the remaining driving circuits are coupled to the parallel interface of the first driving circuit, the serial output interface of the last driving circuit in each of the plurality of light source driving circuits is coupled to a read-back data input interface of the control unit for return output of read-back data.

18. The light source driving circuit according to claim 16, wherein, The first of each light source driving circuit is coupled with the first output interface of the control unit through the serial input interface, and the serial input interface of the rest of each driving circuit is coupled with the serial output interface of the previous driving circuit, and the parallel interface of each driving circuit is coupled with the second output interface of the control unit, the serial output interface of the last of each light source driving circuit is coupled with the read-back data input interface of the control unit for the return output of the read-back data.

19. The light source driving circuit according to claim 14, wherein, the packaged data packets transmitted in the light source driving circuit are received through the serial input interface and the parallel interface, the command or data belonging to the current stage is taken out according to the current stage address, and the subsequent command or data is repackaged, and the data of the serial output interface and the parallel interface of the current stage is monitored to send the repackaged new data packet through the serial output interface and the parallel interface at the same time.

20. The light source driving circuit according to claim 14, wherein, the repackaged data packet is received in the light source driving circuit through the serial input interface and the parallel interface, and the light source driving circuit selects the data packet first arrived through the two interfaces, the command or data belonging to the current stage is taken out according to the current stage address, and the subsequent command or data is repackaged, and the data of the serial output interface and the parallel interface of the current stage is monitored to send the repackaged new data packet through the serial output interface and the parallel interface at the same time.

21. The light source driving circuit according to claim 14, wherein, the first of each light source driving circuit receives address data, the first driving circuit takes out the address data required by the current stage, and then repackages the address data of the rest of the driving circuits and transmits the repackaged data packet through the serial output interface, and the light source driving circuit of the next stage transmits the address data in turn.

22. The light source driving circuit of claim 21, wherein, Each driving circuit has a non-volatile memory for storing the address data of the driving circuit.

23. The light source driving circuit of claim 21, wherein, Each of the light source driving circuits generates the address data packet of the light source driving circuit of the next stage after intercepting the address of the light source driving circuit of the current stage from the address data packet provided by the control unit, or performs addition operation or subtraction operation on the valid address data of the light source driving circuit of the current stage to obtain the address data packet of the subsequent light source driving circuit.

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