Mini LED backlight control circuit, display device and method

Abstract

The present application relates to a Mini LED backlight control circuit, a display device and a method, and the circuit includes a backlight brightness controller and N LED driver chips. Each control channel of the controller uses a pair of transmission lines to connect the aforementioned chips under the control of the channel. After the circuit is powered on, the controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line to reset each chip. After the controller initializes each chip through the low-speed bidirectional transmission line, the controller assigns an address to each chip on the path through the high-speed unidirectional transmission line, and then transmits a backlight control data packet to each chip through the high-speed unidirectional transmission line at each frame time of the image, and reads the working status of the specified chip through the low-speed bidirectional transmission line. The controller is also used to calibrate the clock of each chip through the low-speed bidirectional transmission line. The technical effect of strong adaptability of Mini LED backlight control is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of image communication technology and relates to a Mini LED backlight control circuit, a display device and a method. Background Art

[0002] Mini-LED (sub-millimeter light-emitting diode) backlight partition control technology is the key to improving the HDR (High Dynamic Range) of LCD panels. For single-layer PCB (Printed circuit board) substrates and glass substrate-type backlight panels, the backlight LED (Light-emitting Diode) driver chip requires the least pins, and there needs to be a transmission signal line from DCON (Dimming Controller) to each LED driver chip. This transmission signal line needs to transmit the control signal from DCON to each LED driver chip (generally PWM (Pulse width modulation) encoding signal, and each frame of the image needs to be dynamically updated), as well as the feedback signal from each LED driver chip to DCON (generally used to feedback the internal status of the LED driver chip, such as open circuit, short circuit and overtemperature).

[0003] The commonly used interface between traditional backlight control and backlight drive is the SPI (Serial Peripheral Interface) interface, which consists of multiple signal lines. The timing control, transmission rate, transmission distance and requirements for the number of PCB wiring layers all have obvious limitations in backlight design. At present, the rapid development and rapid increase in the application of Mini-LED backlight, especially the Mini-LED backlight in AM (Active Matrix) driving mode, has been rapidly developed due to its advantages of low power consumption and low cost, but there is a new interface demand to break through the above limitations. In this regard, the current Mini-LED backlight in AM driving mode adopts a single-line communication method. However, in the process of realizing the present invention, the inventors found that the traditional single-line communication has the technical problem of poor adaptability. Summary of the invention

[0004] In view of the problems existing in the above-mentioned traditional methods, the present invention proposes a Mini LED backlight control circuit with strong adaptability, a display device and a Mini LED backlight control method.

[0005] In order to achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] On the one hand, a Mini LED backlight control circuit is provided, including a backlight brightness controller and N LED driver chips, each control channel of the backlight brightness controller uses a pair of transmission lines to connect each LED driver chip under the channel, and the LED driver chip is used to drive the Mini LED partition under its jurisdiction, and N is a positive integer not limited to 2;

[0007] Each pair of transmission lines includes a high-speed unidirectional transmission line and a low-speed bidirectional transmission line. After the circuit is powered on, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively, and each LED driver chip performs a reset operation after receiving the reset signal;

[0008] After resetting each LED driver chip, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line, and each LED driver chip performs an initialization operation after receiving the initialization command;

[0009] After initializing each LED driver chip, the backlight brightness controller assigns addresses to each LED driver chip on the path through a high-speed unidirectional transmission line;

[0010] After completing the address assignment, the backlight brightness controller transmits the backlight control data packet to each LED driver chip on the path through the high-speed unidirectional transmission line at each frame of the image, and reads the working status of the specified LED driver chip on the path through the low-speed bidirectional transmission line; the backlight brightness controller is also used to perform online clock calibration on each LED driver chip on the path through the low-speed bidirectional transmission line.

[0011] In one of the embodiments, when an abnormality occurs in the backlight brightness controller or the LED driving chip, the backlight brightness controller is further configured to send a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.

[0012] In one embodiment, when the backlight brightness controller assigns an address to each LED driver chip on the path through the high-speed unidirectional transmission line, the backlight brightness controller sends a shutdown instruction on the high-speed unidirectional transmission line; the shutdown instruction is used to instruct all LED driver chips on the path to shut down the high-speed unidirectional transmission line output;

[0013] The backlight brightness controller sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line; the address assignment instruction is used to instruct the first LED driver chip on the path to perform address assignment, and the opening instruction is used to instruct the first LED driver chip to open the high-speed unidirectional transmission line output after assignment;

[0014] After the first LED driver chip completes address assignment and opens the high-speed unidirectional transmission line output, the backlight brightness controller cyclically sends address assignment instructions and opening instructions on the high-speed unidirectional transmission line to assign addresses to the remaining LED driver chips on the path one by one.

[0015] In one embodiment, the backlight brightness controller includes a digital control circuit, a buffer D1, a buffer D2 and a signal transmitter, wherein the digital control circuit sends a signal to a high-speed unidirectional transmission line through the buffer D1;

[0016] The digital control circuit receives the signal on the low-speed bidirectional transmission line through the buffer D2 and sends the signal to the low-speed bidirectional transmission line through the signal transmitter;

[0017] The signal transmitter includes a buffer D3 and a transistor Q, the input end of the buffer D3 is connected to the digital control circuit, the output end of the buffer D3 is connected to the gate of the transistor Q, the drain of the transistor Q is connected to the low-speed bidirectional transmission line, and the source of the transistor Q is grounded.

[0018] In one embodiment, the LED driver chip includes a digital control circuit, a buffer D1, a buffer D2, a buffer D4 and a signal transmitter;

[0019] The digital control circuit receives the signal on the high-speed unidirectional transmission line through the buffer D2, and receives the signal on the low-speed bidirectional transmission line through the buffer D4. The digital control circuit sends the signal to the low-speed bidirectional transmission line through the signal transmitter. The buffer D1 is used to receive the signal on the high-speed unidirectional transmission line and forward it to the next-level LED driver chip.

[0020] The signal transmitter includes a buffer D3 and a transistor Q, the input end of the buffer D3 is connected to the digital control circuit, the output end of the buffer D3 is connected to the gate of the transistor Q, the drain of the transistor Q is connected to the low-speed bidirectional transmission line, and the source of the transistor Q is grounded.

[0021] On the other hand, a display device is also provided, including a Mini LED unit board and the above-mentioned Mini LED backlight control circuit, and the Mini LED unit board includes multiple Mini LED partitions.

[0022] On the other hand, a Mini LED backlight control method is provided, which is applied to a Mini LED backlight control circuit, wherein the circuit includes a backlight brightness controller and N LED driver chips, each control channel of the backlight brightness controller uses a pair of transmission lines to connect each LED driver chip under the channel, and the LED driver chip is used to drive the Mini LED partition under its jurisdiction, where N is a positive integer not limited to 2; each pair of transmission lines includes a high-speed unidirectional transmission line and a low-speed bidirectional transmission line, and the above method includes:

[0023] After the circuit is powered on, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively; the reset signal is used to instruct each LED driver chip to perform a reset operation;

[0024] After resetting each LED driver chip, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line; the initialization command is used to instruct each LED driver chip to perform an initialization operation;

[0025] After initializing each LED driver chip, the backlight brightness controller assigns addresses to each LED driver chip on the path through a high-speed unidirectional transmission line;

[0026] After completing the address assignment, the backlight brightness controller transmits the backlight control data packet to each LED driver chip on the path through the high-speed unidirectional transmission line at each frame of the image, and reads the working status of the specified LED driver chip on the path through the low-speed bidirectional transmission line; the backlight control data packet is used to instruct each LED driver chip to drive the Mini LED partition under its jurisdiction to adjust the backlight.

[0027] In one embodiment, the method further comprises:

[0028] At the set calibration time node, the backlight brightness controller sends a clock signal with set coding rules to each LED driver chip on the path through a low-speed bidirectional transmission line before or after reading the working status of the specified LED driver chip; the clock signal is used to instruct each LED driver chip to perform online clock calibration using the clock signal as a reference clock. The calibration time nodes include a set single calibration time point, a time point when each frame of image processing is completed, or a time point when every M frames of image processing is completed, where M is a positive integer not less than 2.

[0029] In one of the embodiments, the method further comprises: when an abnormality occurs in the backlight brightness controller or the LED driver chip, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.

[0030] In one embodiment, the process of assigning addresses to each LED driver chip on the path through a high-speed unidirectional transmission line by the backlight brightness controller includes:

[0031] The backlight brightness controller sends a shutdown command on the high-speed unidirectional transmission line; the shutdown command is used to instruct all LED driver chips in the path to shut down the high-speed unidirectional transmission line output;

[0032] The backlight brightness controller sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line; the address assignment instruction is used to instruct the first LED driver chip on the path to perform address assignment, and the opening instruction is used to instruct the first LED driver chip to open the high-speed unidirectional transmission line output after assignment;

[0033] After the first LED driver chip completes address assignment and opens the high-speed unidirectional transmission line output, the backlight brightness controller loops through the steps of sending address assignment instructions and opening instructions on the high-speed unidirectional transmission line until the address assignment of all remaining LED driver chips in the path is completed.

[0034] One of the above technical solutions has the following advantages and beneficial effects:

[0035] The above-mentioned Mini LED backlight control circuit, device and Mini LED backlight control method adopt a two-wire transmission communication mode between the backlight brightness controller and the LED driver chip: for each control channel of the backlight brightness controller, a high-speed unidirectional transmission line and a low-speed bidirectional transmission line are used for two-wire transmission communication, the high-speed unidirectional transmission line is used to transmit the backlight control data packet and assign addresses to the LED driver chips on the path, and the low-speed bidirectional transmission line is used to initialize the path, LED driver chip status feedback and online clock calibration, etc., so as to realize the required Mini LED backlight control function and effectively realize the efficient signal transmission from DCON to LED driver chip on a single-layer PCB board or glass substrate. While transmitting each frame of backlight data, it can feedback the current state of the LED driver chip in real time, support the complex requirements of system applications, and calibrate the clock of the LED driver chip to adjust the control of the LED driver chip. The two-wire full-time collaboration supports different channel coding methods, so that it can be expanded to support more complex backlight system designs and achieve a technical effect with strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a structural diagram of an existing SPI interface;

[0038] Figure 2 It is a schematic diagram of the structure of a Mini LED backlight control circuit in one embodiment;

[0039] Figure 3A schematic diagram of a signal encoding method of DB and DC taken as an example in an embodiment;

[0040] Figure 4 This is a schematic diagram of the structure of a Mini LED backlight control circuit in another embodiment;

[0041] Figure 5 1 is a schematic diagram of a flow chart of a Mini LED backlight control method in one embodiment;

[0042] Figure 6 Schematic diagram of the flow of a Mini LED backlight control method in another embodiment. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] It should be noted that the reference to "embodiment" in this document means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The presentation of the phrase at various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0046] Those skilled in the art will appreciate that the embodiments described herein may be combined with other embodiments. The term "and / or" used in the present specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0047] SPI is a high-speed, full-duplex and synchronous communication bus, and only occupies four wires on the chip pins, saving the chip pins and providing convenience for saving space on the PCB substrate layout. It is precisely because of this simple and easy-to-use feature that more chips are integrated with this communication protocol. The commonly used SPI interface between the traditional LED backlight control and the backlight driver can be as follows Figure 1As shown in the figure, the master-slave control mode is adopted. The SPI interface protocol stipulates that the communication between two SPI devices must be controlled by the master device (SPI Master) to control the slave device (SPI Slave). An SPI Master device can control multiple SPI Slave devices by providing the clock Clock and performing chip selection (Slave Select) on the SPI Slave device. The SPI interface protocol also stipulates that the clock Clock of the SPI Slave device is provided to the SPI Slave device by the SPI Master device through the SCLK pin. The SPI Slave device itself cannot generate or control the Clock. Without the Clock, the SPI Slave device cannot work properly.

[0048] like Figure 1 In the SPI Master, the main function of the SCLK pin is to transmit the clock signal from the SPI Master device to the SPI Slave device to control the timing and rate of data exchange; the main function of the MOSI pin is to serve as the data outlet, mainly used for the SPI device to send data; the main function of the MISO pin is to serve as the data entry, mainly used for the SPI device to receive data; the main function of the CS pin is to be used by the SPI Master device to select the SPI Slave device, so that the selected SPI Slave device can be accessed by the SPI Master device. However, due to its limitations in backlight design, it cannot be applied to the Mini LED backlight field. In this regard, there are also some single-line communication methods in the industry that are applied to the Mini LED backlight field, but the system speed of the single-line communication backlight control system cannot meet the requirements of increasingly complex system applications. At the same time, the channel encoding and decoding can only be simple, and it cannot be expanded to support more complex backlight system designs, and there are obvious adaptability limitations.

[0049] In this context, the inventors proposed a new dual-line transmission Mini LED backlight control solution to ensure that each LED driver chip can normally drive each Mini LED partition, which can well solve the aforementioned applicability limitations.

[0050] The following will describe the implementation of the present invention in detail with reference to the accompanying drawings in the embodiment diagram of the present invention.

[0051] See also Figure 2In one embodiment, the present application provides a Mini LED backlight control circuit 100, including a backlight brightness controller 12 and N LED driver chips 14. Each control channel of the backlight brightness controller 12 uses a pair of transmission lines to connect each LED driver chip 14 under the channel. The LED driver chip 14 is used to drive the Mini LED partition under its jurisdiction. N is a positive integer not limited to 2, Figure 2 Where n is a positive integer less than N.

[0052] Each pair of transmission lines includes a high-speed unidirectional transmission line and a low-speed bidirectional transmission line. After the circuit is powered on, the backlight brightness controller 12 sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively, and each LED driver chip 14 performs a reset operation after receiving the reset signal. After resetting each LED driver chip 14, the backlight brightness controller 12 sends an initialization command to the low-speed bidirectional transmission line, and each LED driver chip 14 performs an initialization operation after receiving the initialization command. After initializing each initialized LED driver chip 14, the backlight brightness controller 12 assigns addresses to each LED driver chip 14 on the path through the high-speed unidirectional transmission line. After completing the address assignment, the backlight brightness controller 12 transmits a backlight control data packet to each LED driver chip 14 on the path through the high-speed unidirectional transmission line at each frame time of the image, and reads the working status of the specified LED driver chip 14 on the path through the low-speed bidirectional transmission line. The backlight brightness controller 12 is also used to perform online clock calibration on each LED driver chip 14 on the path through the low-speed bidirectional transmission line.

[0053] It can be understood that the backlight brightness controller 12 is also called DCON. A backlight brightness controller 12 can have multiple control channels, each of which can control multiple LED driver chips 14 on a path, and each LED driver chip 14 is used to drive each LED partition corresponding to it. The specific number of LED driver chips 14 can be determined according to the specific specifications of the Mini LED display screen used. In some application scenarios, the number of backlight brightness controllers 12 can be more than one, and the specific number can be set according to the needs of the Mini LED display screen actually used. The above-mentioned two-wire transmission communication method can be used between each backlight brightness controller 12 and each LED driver chip 14 it controls to achieve more adaptable backlight control.

[0054] Regarding the high-speed unidirectional transmission line and the low-speed bidirectional transmission line, the high speed and low speed are named based on the relative high and low data transmission rates between the two transmission lines. The high-speed unidirectional transmission line is a signal line for unidirectional data transmission (i.e., from the backlight brightness controller 12 to the LED driver chip 14), and its data transmission rate is higher than the data transmission rate of the low-speed bidirectional transmission line. The low-speed bidirectional transmission line is a signal line for bidirectional data transmission (i.e., it can be transmitted from the backlight brightness controller 12 to the LED driver chip 14, and it can also be transmitted from the LED driver chip 14 to the backlight brightness controller 12). The data transmission rates in the high-speed unidirectional transmission line and the low-speed bidirectional transmission line can be set according to the needs of the actual application.

[0055] Specifically, in the backlight control process, after the above-mentioned Mini LED backlight control circuit 100 is powered on, the working relationship between the backlight brightness controller 12 and the LED driver chip 14 can be as follows: taking the backlight control under any control channel of the backlight brightness controller 12 as an example (the backlight control of other control channels is the same), the control channel corresponds to a signal transmission path (supported by a pair of transmission lines), and the path includes multiple LED driver chips 14; after the circuit is powered on, the backlight brightness controller 12 will send a reset signal to the high-speed unidirectional transmission line (hereinafter referred to as DB) and the low-speed bidirectional transmission line (hereinafter referred to as DC), and reset all the LED driver chips 14 on the path.

[0056] After all the LED driver chips 14 on the path are reset, the backlight brightness controller 12 sends an initialization command for all the LED driver chips 14 on the path to the low-speed bidirectional transmission line to perform initialization operations on all the LED driver chips 14 on the path, such as but not limited to setting the transmission rate of the LED driver chip 14, the ratio of the DB high-speed signal rate and the DC low-speed signal rate, and initialization of registers shared by all other LED driver chips 14. The specific initialization operation can be determined according to the needs of different actual application scenarios.

[0057] After completing the initialization of all LED driver chips 14 on the path, the backlight brightness controller 12 assigns addresses to all LED driver chips 14 on the path one by one on DB (because the driving mode is AM mode), and the address assignment of each LED driver chip 14 on the path is different. For the current frame of the image, after receiving the backlight data of the frame of the image, the backlight brightness controller 12 transmits the corresponding backlight control data packet to each LED driver chip 14 on the path on DB, so that each LED driver chip 14 drives the corresponding LED partition to adjust the backlight according to the received backlight control data packet, so that the screen can accurately display the frame of the image.

[0058] When the backlight brightness controller 12 transmits the corresponding backlight control data packet to each LED driver chip 14 on the path, it can send a status feedback instruction on the DC to read the working status of the specified LED driver chip 14. After receiving the status feedback instruction, the specified LED driver chip 14 will feedback the corresponding working status information to the backlight brightness controller 12 through the DC to monitor the working status of the specified LED driver chip 14. The specified LED driver chip 14 can be specifically set according to the actual application needs, for example, a certain LED driver chip 14 or several LED driver chips 14 on the path can be specified, or all LED driver chips 14 on the path can be selected.

[0059] When necessary, for example but not limited to after the backlight control processing of each frame of image is completed, or after the backlight control processing of every few frames of image is completed, or only a calibration time is set to perform clock calibration only once after power-on, the backlight brightness controller 12 sends a clock signal that complies with the required encoding rules on the DC to each LED driver chip 14 on the path before or after reading the status of the LED driver chip 14, so that each LED driver chip 14 uses the received clock signal as a reference clock to calibrate the clock inside the LED driver chip 14.

[0060] In this way, when the backlight control of the current frame image is completed, the backlight brightness controller 12 or the LED driver chip 14 has no known working abnormalities, that is, the communication transmission of the backlight control of the frame image is completed, waiting for the arrival of the next frame image and repeating the above-mentioned backlight control working process for each frame time.

[0061] The above-mentioned Mini LED backlight control circuit 100 adopts a two-wire transmission communication mode between the backlight brightness controller 12 and the LED driver chip 14: for each control channel of the backlight brightness controller 12, a high-speed unidirectional transmission line and a low-speed bidirectional transmission line are used for two-wire transmission communication. The high-speed unidirectional transmission line is used to transmit the backlight control data packet and assign addresses to the LED driver chip 14 on the path. The low-speed bidirectional transmission line is used to initialize the path, LED driver chip 14 state feedback and online clock calibration, etc., so as to realize the required Mini LED backlight control function and effectively realize the efficient signal transmission from DCON to LED driver chip 14 on a single-layer PCB board or glass substrate. While transmitting each frame of backlight data, the current state of the LED driver chip 14 can be fed back in real time, supporting complex requirements of system applications, and the clock of the LED driver chip 14 can also be calibrated to adjust the control of the LED driver chip 14. The two-wire full-time collaboration supports different channel coding methods, so that it can be expanded to support more complex backlight system designs and achieve a technical effect with strong adaptability.

[0062] In one embodiment, Figure 3 As shown, the channel coding method of DB and DC can be but not limited to 1'b0 or 1'b1. Among them, 1'b0 represents that one bit width of the clock signal includes 1 / 4 of the low level and 3 / 4 of the high level, and 1'b1 represents that one bit width of the clock signal includes 3 / 4 of the low level and 1 / 4 of the high level. The reset signal (reset) can use a signal with all low levels within one bit width. In addition, a clock signal with 1 / 8 of the low level and 7 / 8 of the high level within one bit width, or a clock signal or reset signal with other coding methods with different proportions of high and low levels can also be used. The specific selection can be made according to the needs of the actual application scenario, as long as the required clock calibration and circuit reset functions can be achieved.

[0063] Through the above-mentioned dual-line transmission communication of DB and DC, it is possible to expand and support a variety of channel coding methods.

[0064] In one embodiment, when an abnormality occurs in the backlight brightness controller 12 or the LED driving chip 14, the backlight brightness controller 12 is further configured to send a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.

[0065] It can be understood that in this embodiment, if DCON or the LED driver chip 14 malfunctions during the clock calibration process of the LED driver chip 14, DCON will send a reset signal on DB and DC to reset the circuit and restart backlight control.

[0066] By adopting the above reset design, when the DCON or LED driver chip 14 works abnormally, the circuit can be quickly reset through two-wire communication, thereby improving the self-correction capability of the backlight control.

[0067] In one embodiment, when the backlight brightness controller 12 assigns addresses to each LED driver chip 14 on the path through the high-speed unidirectional transmission line, the backlight brightness controller 12 sends a close instruction on the high-speed unidirectional transmission line; the close instruction is used to instruct all LED driver chips 14 on the path to turn off the high-speed unidirectional transmission line output. The backlight brightness controller 12 sends an address assignment instruction and an open instruction on the high-speed unidirectional transmission line; the address assignment instruction is used to instruct the first LED driver chip 14 on the path to perform address assignment, and the open instruction is used to instruct the first LED driver chip 14 to turn on the high-speed unidirectional transmission line output after the assignment. After the first LED driver chip 14 completes the address assignment and turns on the high-speed unidirectional transmission line output, the backlight brightness controller 12 cyclically sends the address assignment instruction and the open instruction on the high-speed unidirectional transmission line to assign addresses to the remaining LED driver chips 14 on the path one by one.

[0068] It can be understood that in this embodiment, the specific process of DCON assigning addresses to each LED driver chip 14 on the path one by one on DB can be as follows. First, DCON sends a shutdown instruction on DB to turn off the DB output of all LED driver chips 14. When the LED driver chip 14 receives the shutdown instruction and turns off the DB signal line output, only the first LED driver chip 14 can receive the DCON instruction. Then DCON sends an address assignment instruction (which can be called an address assignment instruction) and an instruction to turn on the DB signal line output (which can be called an open instruction) on DB. After receiving the address assignment instruction, the first LED driver chip 14 assigns an address to itself and turns on the DB output. At this time, the first LED driver chip 14 and the second LED driver chip 14 can both receive the DCON instruction. Then DCON sends an address assignment instruction and an open instruction to turn on the DB signal line output. Since the first LED driver chip 14 has been assigned an address, it will not take any action after receiving the instruction again. Instead, the second LED driver chip 14 assigns its own address (the address of each LED driver chip 14 is different), and opens the DB signal line output. At this time, the first three LED driver chips 14 can receive the DCON instruction. And so on, the address assignment of all LED driver chips 14 on the path is completed.

[0069] By adopting the above-mentioned DCON to control the address assignment of the LED driver chip 14 through DB, the address assignment of all LED driver chips 14 can be completed efficiently and accurately, and the communication efficiency and reliability are higher.

[0070] In one embodiment, Figure 4 As shown, the backlight brightness controller 12 includes a digital control circuit 122, a buffer D1, a buffer D2 and a signal transmitter. The digital control circuit 122 sends a signal to the high-speed unidirectional transmission line DB through the buffer D1. The digital control circuit 122 receives a signal on the low-speed bidirectional transmission line DC through the buffer D2 and sends a signal to the low-speed bidirectional transmission line DC through the signal transmitter. Among them, the signal transmitter includes a buffer D3 and a transistor Q, the input end of the buffer D3 is connected to the digital control circuit 122, the output end of the buffer D3 is connected to the gate of the transistor Q, the drain of the transistor Q is connected to the low-speed bidirectional transmission line DC, and the source of the transistor Q is grounded.

[0071] It can be understood that in the above embodiment, the connection structure between the specific signal transmission lines of DB and DC and the backlight brightness controller 12 can be selected in a variety of forms, as long as the required communication function can be achieved. In this embodiment, preferably, the line structure between DB and DC and the backlight brightness controller 12 can be specifically adopted as follows: Figure 4The signal line structure shown in FIG. 1 is a signal line structure in which the buffer D1 is used as a receiver to receive the signal from the transmission line and then send it out as it is. For example, the signal sent from DCON first reaches the first LED driver chip 14, and then passes through the buffer D1 of the first LED driver chip 14 to the second LED driver chip 14. The buffer D2 is also used as a receiver to receive signals on DB and DC respectively, while the buffer D3 and the transistor Q together constitute a signal transmitter, which can support the digital control circuit 122 to send signals to DC, such as feedback of working status, etc.

[0072] DC can actually be regarded as an open-drain output signal bus, and DCON and all LED driver chips 14 can send and receive signals on this bus. Figure 4 The schematic diagram shows the connection relationship between the dual transmission lines and each circuit unit part inside the backlight brightness controller 12. This structure can avoid increasing the complexity of the circuit structure while improving the circuit reliability and reducing the circuit production cost.

[0073] In one embodiment, Figure 4 As shown, the LED driver chip 14 includes a digital control circuit 142, a buffer D1, a buffer D2, a buffer D4 and a signal transmitter. The digital control circuit 142 receives a signal on the high-speed unidirectional transmission line DB through the buffer D2, and the digital control circuit 142 receives a signal on the low-speed bidirectional transmission line DC through the buffer D4. The digital control circuit 142 sends a signal to the low-speed bidirectional transmission line DC through the signal transmitter. The buffer D1 is used to receive the signal on the high-speed unidirectional transmission line DB and forward it to the next-level LED driver chip 14. Among them, the signal transmitter includes a buffer D3 and a transistor Q, the input end of the buffer D3 is connected to the digital control circuit 142, the output end of the buffer D3 is connected to the gate of the transistor Q, the drain of the transistor Q is connected to the low-speed bidirectional transmission line DC, and the source of the transistor Q is grounded.

[0074] It can be understood that in the above embodiment, the connection structure between the specific signal transmission lines of DB and DC and the LED driver chip 14 can be selected in a variety of forms, as long as the required communication function can be achieved. In this embodiment, preferably, the line structure between DB and DC and the LED driver chip 14 can be specifically adopted as follows Figure 4The signal line structure shown in the figure, wherein the buffer D1 is used as a receiver to receive the signal transmitted from the transmission line DB and then send it out as it is. For example, the signal sent from DCON first reaches the first LED driver chip 14, and then passes through the buffer D1 of the first LED driver chip 14 to the second LED driver chip 14, and so on. The buffer D2 in the LED driver chip 14 also acts as a receiver and can be used to receive the signal on DB, while the buffer D3 and the transistor Q together constitute a signal transmitter, which can support the digital control circuit 142 to send signals to DC, such as feedback of the working status. The buffer D4 in the LED driver chip 14 also acts as a receiver and can be used to receive the signal on DC. DC is an open-drain output bus mode. When DCON and all LED driver chips 14 are not in action (i.e., transistor Q is turned off), DC is at a high level. When DCON or any LED driver chip 14 is in action (i.e., transistor Q is turned on), DC is at a low level.

[0075] Figure 4 The figure shows the connection relationship between the dual transmission lines and the circuit units inside the LED driver chip 14. The resistor R is a pull-up resistor on the open-drain output bus. The above-mentioned circuit structure can avoid increasing the complexity of the circuit structure, further improve the circuit reliability and reduce the circuit production cost. Figure 4 In FIG. 1 , the arrow on the transmission line indicates the data transmission direction. The specific selection of buffer D1, buffer D2, buffer D3, buffer D4 and transistor Q can be determined according to the circuit specification parameters of the backlight control circuit system of the specific application, as long as it can be used to realize the required communication line function.

[0076] In one embodiment, a display device is further provided, including a Mini LED unit board and the above-mentioned Mini LED backlight control circuit 100, wherein the Mini LED unit board includes a plurality of Mini LED partitions.

[0077] It can be understood that the description and limitation of the Mini LED backlight control circuit 100 in this embodiment can be understood in the same way as the corresponding description and limitation in each embodiment of the Mini LED backlight control circuit 100, and will not be repeated here. A person skilled in the art can understand that the display device referred to here may include other circuit structures in addition to the Mini LED unit board and the Mini LED backlight control circuit 100, which can be understood in the same way as the structural composition of the existing Mini LED display device in the art, and will not be described in detail one by one in this specification.

[0078] The above-mentioned display device, by applying the above-mentioned Mini LED backlight control circuit 100, adopts a two-wire transmission communication method in backlight control, effectively realizing efficient signal transmission from DCON on a single-layer PCB board or glass substrate to the LED driver chip. While transmitting each frame of backlight data, it can provide real-time feedback on the status of the current LED driver chip, support complex requirements of system applications, and calibrate the clock of the LED driver chip to adjust the control of the LED driver chip. The two-wire dedicated collaboration supports different channel coding methods, so that it can be expanded to support more complex backlight system designs and achieve a technical effect with strong adaptability. The above-mentioned technology can be converted into a two-wire transmission Mini LED backlight control interface protocol for promotion and application, thereby promoting the standardization of high backlight control performance of Mini LED display devices.

[0079] In one embodiment, Figure 5 As shown, a Mini LED backlight control method is also provided, which can be applied to a Mini LED backlight control circuit, the circuit includes a backlight brightness controller and N LED driver chips, each control channel of the backlight brightness controller uses a pair of transmission lines to connect each LED driver chip under the channel, and the LED driver chip is used to drive the Mini LED partition under its jurisdiction, N is a positive integer not limited to 2; each pair of transmission lines includes a high-speed unidirectional transmission line and a low-speed bidirectional transmission line. The above method may include the following control steps:

[0080] S12, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively after the circuit is powered on; the reset signal is used to instruct each LED driver chip to perform a reset operation;

[0081] S14, after resetting each LED driver chip, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line; the initialization command is used to instruct each LED driver chip to perform an initialization operation;

[0082] S16, after initializing each LED driver chip, the backlight brightness controller assigns an address to each LED driver chip on the path through a high-speed unidirectional transmission line;

[0083] S18, after completing the address assignment, the backlight brightness controller transmits the backlight control data packet to each LED driver chip on the path through the high-speed unidirectional transmission line at each frame time of the image, and reads the working status of the specified LED driver chip on the path through the low-speed bidirectional transmission line; the backlight control data packet is used to instruct each LED driver chip to drive the Mini LED partition under its jurisdiction to adjust the backlight.

[0084] It can be understood that the specific explanations and descriptions about the backlight brightness controller, LED driver chip, high-speed unidirectional transmission line and low-speed bidirectional transmission line of the LED backlight control circuit in this embodiment can be understood by referring to the corresponding explanations and descriptions in the above-mentioned embodiments of the LED backlight control circuit 100, and will not be repeated here.

[0085] The above-mentioned Mini LED backlight control method adopts a two-wire transmission communication method between the backlight brightness controller and the LED driver chip: for each control channel of the backlight brightness controller, a two-wire transmission communication of a high-speed unidirectional transmission line and a low-speed bidirectional transmission line is adopted, the high-speed unidirectional transmission line is used to transmit the backlight control data packet and assign addresses to the LED driver chips on the path, and the low-speed bidirectional transmission line is used to initialize the path, LED driver chip status feedback and online clock calibration, etc., so as to realize the required Mini LED backlight control function and effectively realize the efficient signal transmission from DCON to LED driver chip on a single-layer PCB board or glass substrate. While transmitting each frame of backlight data, it can feedback the current status of the LED driver chip in real time, support the complex requirements of system applications, and calibrate the clock of the LED driver chip to adjust the control of the LED driver chip. The two-wire full-time collaboration supports different channel coding methods, so that it can be expanded to support more complex backlight system designs and achieve a highly adaptable technical effect.

[0086] In one embodiment, as and Figure 6 As shown, the above method may further include the following control steps:

[0087] At the set calibration time node, the backlight brightness controller sends a clock signal with set coding rules to each LED driver chip on the path through a low-speed bidirectional transmission line before or after reading the working status of the specified LED driver chip; the clock signal is used to instruct each LED driver chip to perform online clock calibration using the clock signal as a reference clock. The calibration time nodes include a set single calibration time point, a time point when each frame of image processing is completed, or a time point when every M frames of image processing is completed, where M is a positive integer not less than 2.

[0088] In one embodiment, as and Figure 6 As shown, the above method may further include the following control step: when an abnormality occurs in the backlight brightness controller or the LED driving chip, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.

[0089] In one embodiment, the process of the backlight brightness controller assigning addresses to each LED driver chip on the path through a high-speed unidirectional transmission line may specifically include the following steps:

[0090] The backlight brightness controller sends a shutdown command on the high-speed unidirectional transmission line; the shutdown command is used to instruct all LED driver chips in the path to shut down the high-speed unidirectional transmission line output;

[0091] The backlight brightness controller sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line; the address assignment instruction is used to instruct the first LED driver chip on the path to perform address assignment, and the opening instruction is used to instruct the first LED driver chip to open the high-speed unidirectional transmission line output after assignment;

[0092] After the first LED driver chip completes address assignment and opens the high-speed unidirectional transmission line output, the backlight brightness controller loops through the steps of sending address assignment instructions and opening instructions on the high-speed unidirectional transmission line until the address assignment of all remaining LED driver chips in the path is completed.

[0093] For the specific explanation of each additional step or sub-step of the above-mentioned Mini LED backlight control method, you can refer to the explanation of the corresponding working process in each embodiment of the above-mentioned LED backlight control circuit 100, and will not be repeated here.

[0094] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and all of them belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A Mini LED backlight control circuit, characterized in that: It includes a backlight brightness controller and N LED driver chips, each control channel of the backlight brightness controller uses a pair of transmission lines to connect the LED driver chips under the channel, and the LED driver chip is used to drive the Mini LED partition under its jurisdiction, and N is a positive integer not limited to 2; Each pair of the transmission lines includes a high-speed unidirectional transmission line and a low-speed bidirectional transmission line. After the circuit is powered on, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively, and each LED driver chip performs a reset operation after receiving the reset signal. After resetting each of the LED driver chips, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line, and each of the LED driver chips performs an initialization operation after receiving the initialization command; After initializing each of the LED driver chips, the backlight brightness controller assigns an address to each of the LED driver chips on the path through the high-speed unidirectional transmission line; After completing the address assignment, at each frame time of the image, the backlight brightness controller transmits a backlight control data packet to each LED driver chip on the path through the high-speed unidirectional transmission line, and reads the working status of the specified LED driver chip on the path through the low-speed bidirectional transmission line; the backlight brightness controller is also used to perform online clock calibration on each LED driver chip on the path through the low-speed bidirectional transmission line.

2. The Mini LED backlight control circuit according to claim 1, characterized in that: When an abnormality occurs in the backlight brightness controller or the LED driving chip, the backlight brightness controller is further used to send a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.

3. The Mini LED backlight control circuit according to claim 1 or 2, characterized in that: When the backlight brightness controller assigns an address to each LED driver chip on the path through the high-speed unidirectional transmission line, the backlight brightness controller sends a shutdown instruction on the high-speed unidirectional transmission line; the shutdown instruction is used to instruct all the LED driver chips on the path to shut down the output of the high-speed unidirectional transmission line; The backlight brightness controller sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line; the address assignment instruction is used to instruct the first LED driver chip on the path to perform address assignment, and the opening instruction is used to instruct the first LED driver chip to open the high-speed unidirectional transmission line output after assignment; After the first LED driver chip completes address assignment and opens the high-speed unidirectional transmission line output, the backlight brightness controller cyclically sends address assignment instructions and opening instructions on the high-speed unidirectional transmission line to perform address assignment for the remaining LED driver chips on the path one by one.

4. The Mini LED backlight control circuit according to claim 3, characterized in that: The backlight brightness controller comprises a digital control circuit, a buffer D1, a buffer D2 and a signal transmitter, wherein the digital control circuit sends a signal to the high-speed unidirectional transmission line through the buffer D1; The digital control circuit receives the signal on the low-speed bidirectional transmission line through the buffer D2 and sends the signal to the low-speed bidirectional transmission line through the signal transmitter; The signal transmitter includes a buffer D3 and a transistor Q, the input end of the buffer D3 is connected to the digital control circuit, the output end of the buffer D3 is connected to the gate of the transistor Q, the drain of the transistor Q is connected to the low-speed bidirectional transmission line, and the source of the transistor Q is grounded.

5. The Mini LED backlight control circuit according to claim 3, characterized in that: The LED driver chip includes a digital control circuit, a buffer D1, a buffer D2, a buffer D4 and a signal transmitter; The digital control circuit receives the signal on the high-speed unidirectional transmission line through the buffer D2, the digital control circuit receives the signal on the low-speed bidirectional transmission line through the buffer D4, the digital control circuit sends the signal to the low-speed bidirectional transmission line through the signal transmitter, and the buffer D1 is used to receive the signal on the high-speed unidirectional transmission line and forward it to the LED driver chip of the next level; The signal transmitter includes a buffer D3 and a transistor Q, the input end of the buffer D3 is connected to the digital control circuit, the output end of the buffer D3 is connected to the gate of the transistor Q, the drain of the transistor Q is connected to the low-speed bidirectional transmission line, and the source of the transistor Q is grounded.

6. A display device, characterized in that: It comprises a Mini LED unit board and the Mini LED backlight control circuit according to any one of claims 1 to 5, wherein the Mini LED unit board comprises a plurality of Mini LED partitions.

7. A Mini LED backlight control method, applied to a Mini LED backlight control circuit, the circuit comprising a backlight brightness controller and N LED driver chips, each control channel of the backlight brightness controller uses a pair of transmission lines to connect the LED driver chips under the channel, the LED driver chip is used to drive the Mini LED partition under its jurisdiction, N is a positive integer not limited to 2; each pair of the transmission lines comprises a high-speed unidirectional transmission line and a low-speed bidirectional transmission line, characterized in that, The method comprises: The backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively after the circuit is powered on; the reset signal is used to instruct each of the LED driver chips to perform a reset operation; After resetting each of the LED driver chips, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line; the initialization command is used to instruct each of the LED driver chips to perform an initialization operation; After initializing each of the LED driver chips, the backlight brightness controller assigns an address to each of the LED driver chips on the path through the high-speed unidirectional transmission line; After completing the address assignment, the backlight brightness controller transmits a backlight control data packet to each LED driver chip on the path through the high-speed unidirectional transmission line at each frame time of the image, and reads the working status of the specified LED driver chip on the path through the low-speed bidirectional transmission line; the backlight control data packet is used to instruct each LED driver chip to drive the Mini LED partition under its jurisdiction to adjust the backlight.

8. The Mini LED backlight control method according to claim 7, characterized in that: Also includes: At the set calibration time node, the backlight brightness controller sends a clock signal with set coding rules to each LED driver chip on the path through the low-speed bidirectional transmission line before or after reading the working status of the specified LED driver chip; the clock signal is used to instruct each LED driver chip to perform online clock calibration with the clock signal as the reference clock, and the calibration time node includes a set single calibration time point, a time point when each frame of image processing is completed, or a time point when every M frames of image processing are completed, where M is a positive integer not less than 2.

9. The Mini LED backlight control method according to claim 7 or 8, characterized in that: Also includes: When an abnormality occurs in the backlight brightness controller or the LED driving chip, the backlight brightness controller sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.

10. The Mini LED backlight control method according to claim 9, characterized in that: The process of the backlight brightness controller assigning addresses to the LED driver chips on the path through the high-speed unidirectional transmission line includes: The backlight brightness controller sends a shutdown instruction on the high-speed unidirectional transmission line; the shutdown instruction is used to instruct all the LED driver chips on the path to shut down the output of the high-speed unidirectional transmission line; The backlight brightness controller sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line; the address assignment instruction is used to instruct the first LED driver chip on the path to perform address assignment, and the opening instruction is used to instruct the first LED driver chip to open the high-speed unidirectional transmission line output after assignment; After the first LED driver chip completes address assignment and opens the high-speed unidirectional transmission line output, the backlight brightness controller loops through the steps of sending address assignment instructions and opening instructions on the high-speed unidirectional transmission line until the address assignment of all remaining LED driver chips on the path is completed.

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