CN114999409B - Mini LED backlight control circuit, display device and method - Google Patents
Mini LED backlight control circuit, display device and method Download PDFInfo
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- CN114999409B CN114999409B CN202210703199.9A CN202210703199A CN114999409B CN 114999409 B CN114999409 B CN 114999409B CN 202210703199 A CN202210703199 A CN 202210703199A CN 114999409 B CN114999409 B CN 114999409B
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
- G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
本申请涉及Mini LED背光控制电路、显示设备和方法，该电路包括背光亮度控制器和N颗LED驱动芯片。该控制器的每条控制通道均采用一对传输线连接通道所辖的各前述芯片。在电路上电后控制器分别向高速单向传输线和低速双向传输线发送复位信号对各芯片进行复位。控制器通过低速双向传输线对各芯片进行初始化后，控制器通过高速单向传输线对通路上的各芯片进行地址赋值，然后在图像的每帧时间通过高速单向传输线向各芯片传输背光控制数据包以及通过低速双向传输线读取指定芯片的工作状态。控制器还用于通过低速双向传输线对各芯片进行时钟校准。达到了Mini LED背光控制适应性较强的技术效果。
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
The invention belongs to the technical field of image communication, and relates to a Mini LED backlight control circuit, display equipment and a method.
Background
The backlight partition control technology of Mini-LEDs (sub-millimeter light emitting diodes) is a key to improve the HDR (HIGH DYNAMIC RANGE ) of the liquid crystal panel. For single-layer PCB (Printed circuit board ) substrates and glass substrate type backlight boards, backlight LED (Light-emitting Diode) driving chips require a minimum number of pins, and a transmission signal line is required from DCON (Dimming Controller) to each LED driving chip, and the transmission signal line is required to transmit a control signal (typically PWM (Pulse width modulation) encoded signal for each LED driving chip, and dynamic update is required for each frame of image) from DCON to each LED driving chip, and a feedback signal (typically for feedback of internal states of the LED driving chip, such as open circuit, short circuit, and over temperature) from each LED driving chip to DCON.
The interface commonly used between the traditional backlight control and the backlight driving is an SPI (SERIAL PERIPHERAL INTERFACE ) interface, which consists of a plurality of signal wires, and the time sequence control, the transmission rate, the transmission distance, the requirements on the PCB wiring layers and the like have obvious limitations in the backlight design. The rapid development and rapid increase of applications of Mini-LED backlight at present, especially the Mini-LED backlight in AM (Active Matrix) driving mode is rapidly developed with the advantages of low power consumption and low cost, but has new interface requirements for breaking through the limitations. In contrast, the current AM driving mode Mini-LED backlight adopts a single-wire communication mode. However, in the process of implementing the present invention, the inventor has found that the conventional single-wire communication has a technical problem of poor adaptability.
Disclosure of Invention
Aiming at the problems in the traditional method, the invention provides a Mini LED backlight control circuit with strong adaptability, display equipment and a Mini LED backlight control method.
In order to achieve the above object, the embodiment of the present invention adopts the following technical scheme:
On the one hand, a Mini LED backlight control circuit is provided, which comprises a backlight brightness controller and N LED driving chips, wherein each control channel of the backlight brightness controller adopts a pair of LED driving chips governed by a transmission line connecting channel, the LED driving chips are used for driving the governed Mini LED partitions, and N is a positive integer not limited to 2;
Each pair of transmission lines comprises a high-speed unidirectional transmission line and a low-speed bidirectional transmission line, and after the circuit is electrified, the backlight brightness controller respectively sends reset signals to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line, and each LED driving chip carries out reset operation after receiving the reset signals;
after resetting each LED driving chip, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line, and each LED driving chip receives the initialization command and performs initialization operation;
after initializing each initialized LED driving chip, the backlight brightness controller carries out address assignment on each LED driving chip on the path through a high-speed unidirectional transmission line;
after the address assignment is completed, the backlight brightness controller transmits backlight control data packets to each LED driving chip on the path through a high-speed unidirectional transmission line at each frame time of the image, and reads the working state of the appointed LED driving chip on the path through a low-speed bidirectional transmission line, and the backlight brightness controller is also used for carrying out on-line clock calibration on each LED driving chip on the path through the low-speed bidirectional transmission line.
In one embodiment, 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, when an abnormality occurs in the backlight brightness controller or the LED driving chip.
In one embodiment, when the backlight brightness controller performs address assignment on each LED driving chip on the path through the high-speed unidirectional transmission line, the backlight brightness controller sends a closing instruction on the high-speed unidirectional transmission line, wherein the closing instruction is used for indicating all the LED driving chips on the path to close 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, wherein the address assignment instruction is used for indicating a first LED driving chip on a channel to carry out address assignment, and the opening instruction is used for indicating the first LED driving chip to open the high-speed unidirectional transmission line for output after assignment;
And the backlight brightness controller circularly sends an address assignment instruction and an operation of opening the instruction on the high-speed unidirectional transmission line after the first LED driving chip finishes address assignment and opens the high-speed unidirectional transmission line for output, and carries out address assignment on the rest LED driving chips on the path one by one.
In one embodiment, the backlight brightness controller comprises a digital control circuit, a buffer D1, a buffer D2 and a signal transmitter, wherein the digital control circuit transmits signals to a high-speed unidirectional transmission line through the buffer D1;
The digital control circuit receives signals on the low-speed bidirectional transmission line through a buffer D2 and sends signals to the low-speed bidirectional transmission line through a signal transmitter;
The signal transmitter comprises a buffer D3 and a transistor Q, wherein the input end of the buffer D3 is connected with the digital control circuit, the output end of the buffer D3 is connected with the grid electrode of the transistor Q, the drain electrode of the transistor Q is connected with the low-speed bidirectional transmission line, and the source electrode of the transistor Q is grounded.
In one embodiment, the LED driving chip includes a digital control circuit, a buffer D1, a buffer D2, a buffer D4, and a signal transmitter;
The digital control circuit receives signals on the high-speed unidirectional transmission line through a buffer D2, the digital control circuit receives signals on the low-speed bidirectional transmission line through a buffer D4, the digital control circuit sends signals to the low-speed bidirectional transmission line through a signal transmitter, and the buffer D1 is used for receiving signals on the high-speed unidirectional transmission line and forwarding the signals to an LED driving chip of the next stage;
The signal transmitter comprises a buffer D3 and a transistor Q, wherein the input end of the buffer D3 is connected with the digital control circuit, the output end of the buffer D3 is connected with the grid electrode of the transistor Q, the drain electrode of the transistor Q is connected with the low-speed bidirectional transmission line, and the source electrode of the transistor Q is grounded.
On the other hand, the display device further comprises a Mini LED unit board and the Mini LED backlight control circuit, wherein the Mini LED unit board comprises a plurality of Mini LED partitions.
In still another aspect, a Mini LED backlight control method is provided, and the method is applied to a Mini LED backlight control circuit, the circuit includes a backlight brightness controller and N LED driving chips, each control channel of the backlight brightness controller adopts a pair of LED driving chips governed by a transmission line connecting channel, the LED driving chips are used for driving the governed Mini LED partition, 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 method includes:
the backlight brightness controller respectively sends reset signals to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line after the circuit is powered on;
After resetting each LED driving chip, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line, wherein the initialization command is used for indicating each LED driving chip to perform initialization operation;
after initializing each initialized LED driving chip, the backlight brightness controller carries out address assignment on each LED driving chip on the path through a high-speed unidirectional transmission line;
After the address assignment is completed, the backlight brightness controller transmits a backlight control data packet to each LED driving chip on the path through a high-speed unidirectional transmission line at each frame time of the image, and reads the working state of the appointed LED driving chip on the path through a low-speed bidirectional transmission line, wherein the backlight control data packet is used for indicating each LED driving chip to drive the managed Mini LED partition to carry out backlight adjustment.
In one embodiment, the method further comprises:
And before or after the set calibration time node reads the working state of the designated LED driving chip, the backlight brightness controller sends clock signals for setting the coding rule to each LED driving chip on the path through a low-speed bidirectional transmission line, wherein the clock signals are used for indicating each LED driving chip to perform online clock calibration by taking the clock signals as reference clocks, and the calibration time node comprises a set single calibration time point, a time point when each frame of image processing is completed or a time point when each M frame of image processing is completed, and M is a positive integer not less than 2.
In one embodiment, the method further comprises the step that when the backlight brightness controller or the LED driving chip is abnormal, the backlight brightness controller sends reset signals to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line respectively.
In one embodiment, the process of performing address assignment on each LED driver chip on the path by the backlight brightness controller through the high-speed unidirectional transmission line includes:
The backlight brightness controller sends a closing instruction on the high-speed unidirectional transmission line, wherein the closing instruction is used for indicating all LED driving chips on the passage to close 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, wherein the address assignment instruction is used for indicating a first LED driving chip on a channel to carry out address assignment, and the opening instruction is used for indicating the first LED driving chip to open the high-speed unidirectional transmission line for output after assignment;
and the backlight brightness controller circularly sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line after the first LED driving chip finishes address assignment and opens the high-speed unidirectional transmission line for output until the address assignment of all the other LED driving chips on the path is finished.
One of the above technical solutions has the following advantages and beneficial effects:
According to the Mini LED backlight control circuit, the device and the Mini LED backlight control method, a double-line transmission communication mode is adopted between the backlight brightness controller and the LED driving chips, namely, for each control channel of the backlight brightness controller, double-line 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 for transmitting backlight control data packets and carrying out address assignment on the LED driving chips on a channel, the low-speed bidirectional transmission line is used for initializing the channel, feeding back the state of the LED driving chips, calibrating an on-line clock and the like, so that the required Mini LED backlight control function is realized, and high-efficiency signal transmission from DCON (direct current on-channel) on a single-layer PCB (printed circuit board) or a glass substrate to the LED driving chips is effectively realized. The state of the current LED driving chip can be fed back in real time while each frame of backlight data is transmitted, the complex requirement of the system application is supported, and the clock of the LED driving chip can be calibrated, so that the control of the LED driving chip is adjusted, the two lines are in full-time coordination, different channel coding modes are supported, the design of a more complex backlight system can be supported in an expandable mode, and the technical effect of high adaptability is achieved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.
FIG. 1 is a schematic diagram of a conventional SPI interface;
FIG. 2 is a schematic diagram of a Mini LED backlight control circuit according to an embodiment;
FIG. 3 is a schematic diagram of exemplary DB and DC signal encoding schemes in one embodiment;
fig. 4 is a schematic structural diagram of a Mini LED backlight control circuit according to another embodiment;
FIG. 5 is a flow chart of a Mini LED backlight control method in one embodiment;
Fig. 6 is a flowchart of a Mini LED backlight control method according to another embodiment.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It is noted that reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
Those skilled in the art will appreciate that the embodiments described herein may be combined with other embodiments. The term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.
SPI is a high-speed, full duplex and synchronous communication bus, and only occupies four wires on the pin of chip, has practiced thrift the pin of chip, provides convenience in the overall arrangement for PCB base plate saving space simultaneously, just is because this kind of simple easy-to-use characteristic for more chips have all integrated this kind of communication protocol. The conventional SPI interface commonly used between LED backlight control and backlight driving can be as shown in fig. 1, and adopts a Master-Slave mode (Master-Slave) control manner, and the SPI interface protocol specifies that communication between two SPI devices must be controlled by a Master device (SPI MASTER) to control a secondary device (SPI Slave). One SPI MASTER device can control multiple SPI Slave devices by providing a Clock and performing chip selection (SLAVE SELECT) on the SPI Slave devices, the SPI interface protocol also provides that the Clock of the SPI Slave devices is provided to the SPI Slave devices by the SPI MASTER device through an SCLK pin, the SPI Slave devices cannot generate or control Clock per se, and the SPI Slave devices cannot work normally without Clock.
In fig. 1, the SCLK pin mainly functions to transmit a clock signal to the SPI Slave device by the SPI MASTER device to control the timing and rate of data exchange, the MOSI pin mainly functions as an outlet of data and mainly used for the SPI device to transmit data, the MISO pin mainly functions as an inlet of data and mainly used for the SPI device to receive data, and the CS pin mainly functions for the SPI MASTER device to chip 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 field of Mini LED backlights. In this regard, some single-wire communication methods are applied to the field of Mini LED backlight in the industry, but the system speed of the single-wire communication backlight control system cannot meet the requirement of increasingly complex system application, and meanwhile, the channel coding and decoding can only be in a simple form, so that the design of a backlight system supporting more complex system cannot be expanded, and obvious adaptability limitations exist.
Under the background condition, the inventor provides a new double-line transmission Mini LED backlight control solution, ensures that each LED driving chip can normally drive each Mini LED partition, and can well solve the problem of the limitation of applicability.
Embodiments of the present invention will be described in detail below with reference to the attached drawings in the drawings of the embodiments of the present invention.
Referring to fig. 2, in one embodiment, a Mini LED backlight control circuit 100 is provided, which includes a backlight brightness controller 12 and N LED driving chips 14. Each control channel of the backlight brightness controller 12 adopts a pair of transmission lines to connect the LED driving chips 14 under the control of the channel. The LED driver chip 14 is used to drive the governed Mini LED partition. N is a positive integer not limited to 2, and N is a positive integer less than N in fig. 2.
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 luminance controller 12 sends a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line, respectively, and each LED driving 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 of the initialized LED driver chips 14, the backlight brightness controller 12 performs address assignment on each of the LED driver chips 14 on the path through the high-speed unidirectional transmission line. After the address assignment is completed, the backlight brightness controller 12 transmits a backlight control data packet to each LED driving chip 14 on the path through the high-speed unidirectional transmission line at each frame time of the image, and reads the operating state of the designated LED driving chip 14 on the path through the low-speed bidirectional transmission line. The backlight brightness controller 12 is also used to perform on-line clock calibration on each LED driver chip 14 on the path via a low speed bi-directional transmission line.
It will be appreciated that the backlight brightness controller 12, i.e. DCON, may have a plurality of control channels, each of which may control a plurality of LED driving chips 14 on a path, each LED driving chip 14 being configured to drive each LED segment corresponding thereto. The specific number of LED driver chips 14 may be determined according to the specific specifications of the Mini LED display screen being applied. In some application scenarios, the number of backlight brightness controllers 12 may be more than one, the specific number may be set according to the needs of the Mini LED display screen actually applied, and the backlight brightness controllers 12 and the LED driving chips 14 controlled by the backlight brightness controllers may all adopt the above-mentioned two-wire transmission communication manner to realize backlight control with higher adaptability.
Regarding the high-speed unidirectional transmission line and the low-speed bidirectional transmission line, the high-speed and low-speed unidirectional transmission lines are named based on the relative high and low data transmission rates between the two transmission lines, and the high-speed unidirectional transmission line is a signal line for unidirectional data transmission (i.e., the backlight brightness controller 12 to the LED driving chip 14) whose data transmission rate is higher than that of the low-speed bidirectional transmission line. The low-speed bidirectional transmission line is a signal line for bidirectional data transmission (i.e. the backlight brightness controller 12 can transmit to the LED driving chip 14 or the LED driving chip 14 can transmit 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 practical applications.
Specifically, in the backlight control process, after the Mini LED backlight control circuit 100 is powered on, the operation relationship between the backlight brightness controller 12 and the LED driving chips 14 may be that, taking the backlight control under any control channel of the backlight brightness controller 12 (the backlight control of other control channels is the same), the control channel corresponds to a signal transmission channel (supported by a pair of transmission lines) and includes a plurality of LED driving chips 14, and after the circuit is powered on, the backlight brightness controller 12 sends a reset signal to a high-speed unidirectional transmission line (hereinafter may be referred to as DB) and a low-speed bidirectional transmission line (hereinafter may be referred to as DC) to reset all the LED driving chips 14 on the channel.
After resetting all the LED driver chips 14 on the path, 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, so as to perform initialization operations on all the LED driver chips 14 on the path, for example, but not limited to setting the transmission rate of the LED driver chips 14, DB high-speed signal rate and DC low-speed signal rate ratio, and initializing other registers common to all the LED driver chips 14, where the specific initialization operations may be determined according to the needs of different practical application scenarios.
After initializing all the LED driving chips 14 on the path is completed, the backlight brightness controller 12 performs address assignment on DB for each of the LED driving chips 14 on the path (since the driving mode is the AM mode), and the address assignment for each of the LED driving chips 14 on the path is different. For the image of the previous frame, the backlight brightness controller 12 transmits a corresponding backlight control data packet to each LED driving chip 14 on the path on the DB after receiving the backlight data of the image of the previous frame, so that each LED driving chip 14 drives each corresponding LED partition to perform backlight adjustment according to the received backlight control data packet, thereby enabling the screen to accurately display the image of the previous frame.
When the backlight brightness controller 12 transmits the corresponding backlight control data packet to each LED driving chip 14 on the path, a state feedback instruction for reading the working state of the designated LED driving chip 14 can be sent out on the DC, and after the designated LED driving chip 14 receives the state feedback instruction, the corresponding working state information is fed back to the backlight brightness controller 12 through the DC to monitor the working state of the designated LED driving chip 14. The specific LED driving chips 14 may be specifically set according to practical application requirements, for example, a certain LED driving chip 14 or a certain number of LED driving chips 14 on the specific path may be specified, or all the LED driving chips 14 on the specific path may be selected.
When required, for example, but not limited to, after the backlight control process of each frame of image is completed, or after the backlight control process of each several frames of image is completed, or only one calibration time is set to perform clock calibration only once after power is applied, the backlight brightness controller 12 sends a clock signal meeting the required coding rule to each LED driving chip 14 on the path on DC before or after the state of the LED driving chip 14 is read, so that each LED driving chip 14 uses the received clock signal as a reference clock to calibrate the clock inside the LED driving chip 14.
Thus, when the backlight control of the previous frame image is completed, the backlight brightness controller 12 or the LED driving chip 14 does not generate a known operation abnormality, that is, the communication transmission of the backlight control of the previous frame image is completed, the arrival of the next frame image is waited, and the above-mentioned operation procedure of the backlight control per frame time is repeated.
The Mini LED backlight control circuit 100 adopts a two-wire transmission communication mode between the backlight brightness controller 12 and the LED driving chip 14, namely, adopts two-wire transmission communication of a high-speed unidirectional transmission line and a low-speed bidirectional transmission line for each control channel of the backlight brightness controller 12, wherein the high-speed unidirectional transmission line is used for transmitting backlight control data packets and carrying out address assignment on the LED driving chip 14 on a channel, and the low-speed bidirectional transmission line is used for initializing the channel, feeding back the state of the LED driving chip 14, calibrating an on-line clock and the like, so that the required Mini LED backlight control function is realized, and the efficient signal transmission from DCON on a single-layer PCB board or a glass substrate to the LED driving chip 14 is effectively realized. The state of the current LED driving chip 14 can be fed back in real time while each frame of backlight data is transmitted, the complex requirement of the system application is supported, the clock of the LED driving chip 14 can be calibrated, the control of the LED driving chip 14 is adjusted, the two lines cooperate with each other in full time, different channel coding modes are supported, the more complex backlight system design can be supported in an expanding mode, and the technical effect of high adaptability is achieved.
In one embodiment, as shown in FIG. 3, the channel coding of DB and DC may be, but is not limited to, 1'b0 or 1' b1. Where 1'b0 represents a low level including 1/4 and a high level including 3/4 in one bit width of the clock signal, and 1' b1 represents a low level including 3/4 and a high level including 1/4 in one bit width of the clock signal. The reset signal (reset) may be a signal having a low level within one bit width. In addition, a clock signal with 1/8 low level and 7/8 high level in one bit width or other clock signals or reset signals with high-low level duty ratio in a coding mode can be adopted, and the selection can be specifically carried out according to the needs of practical application scenes, so long as the required clock calibration and circuit reset functions can be realized.
The two-wire transmission communication of DB and DC can expand the channel coding mode supporting diversity.
In one embodiment, 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, when an abnormality occurs in the backlight brightness controller 12 or the LED driving chip 14.
It will be appreciated that in this embodiment, if DCON or the LED driver chip 14 is abnormal during this step clock calibration, DCON will send a reset signal on DB and DC to restart backlight control after circuit reset.
By adopting the resetting design, when the DCON or the LED driving chip 14 works abnormally, circuit resetting can be realized quickly through double-wire communication, and the self-correction capability of backlight control is improved.
In one embodiment, when the backlight brightness controller 12 performs address assignment on each LED driving chip 14 on the path through the high-speed unidirectional transmission line, the backlight brightness controller 12 sends a closing instruction on the high-speed unidirectional transmission line, where the closing instruction is used to instruct all LED driving chips 14 on the path to close the high-speed unidirectional transmission line output. The backlight brightness controller 12 sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line, wherein the address assignment instruction is used for instructing the first LED driving chip 14 on the path to carry out address assignment, and the opening instruction is used for instructing the first LED driving chip 14 to open the high-speed unidirectional transmission line after assignment for outputting. After the first LED driver chip 14 finishes address assignment and opens the high-speed unidirectional transmission line to output, the backlight brightness controller 12 circulates the operations of sending the address assignment instruction and the opening instruction on the high-speed unidirectional transmission line to perform address assignment on the rest LED driver chips 14 on the path one by one.
It will be appreciated that in this embodiment, the specific process of the DCON performing address assignment on the DB for each LED driving chip 14 on the path may be as follows. Firstly, the DCON sends a closing instruction for closing the DB output of all the LED driving chips 14 on the DB, and when the LED driving chips 14 receive the closing instruction and close the DB signal line output, only the first LED driving chip 14 can receive the DCON instruction. And then the DCON sends an address assignment instruction (which may be called an address assignment instruction) and an instruction (which may be called an opening instruction) for opening the DB signal line output on the DB, the first LED driving chip 14 performs address assignment on itself after receiving the address assignment instruction, and then opens the DB for outputting, and at this time, both the first LED driving chip 14 and the second LED driving chip 14 can receive the DCON instruction. And then the DCON sends an address assignment instruction and an opening instruction output by an opening DB signal line. Since the first LED driving chip 14 has performed address assignment, no action will be performed after receiving the instruction again, but after the second LED driving chip 14 performs address assignment on itself (the address of each LED driving chip 14 is different), the DB signal line is turned on to output, and at this time, all the first three LED driving chips 14 can receive the DCON instruction. Similarly, assignment of addresses to all LED driver chips 14 on the path is completed.
By adopting the DCON to control the address assignment of the LED driving chips 14 through the DB, the address assignment of all the LED driving chips 14 can be efficiently and accurately completed, and the communication efficiency and the reliability are higher.
In one embodiment, as shown in fig. 4, 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 transmits a signal to the high-speed unidirectional transmission line DB through the buffer D1. The digital control circuit 122 receives the signal on the low-speed bidirectional transmission line DC through the buffer D2 and transmits the signal to the low-speed bidirectional transmission line DC through the signal transmitter. The signal transmitter includes a buffer D3 and a transistor Q, an input end of the buffer D3 is connected to the digital control circuit 122, an output end of the buffer D3 is connected to a gate of the transistor Q, a drain of the transistor Q is connected to the low-speed bidirectional transmission line DC, and a source of the transistor Q is grounded.
It will be appreciated that in the above embodiments, the connection structure between the specific signal transmission lines of DB and DC and the backlight luminance controller 12 may be variously selected as long as the desired communication function can be achieved. In this embodiment, preferably, the circuit structure between DB and DC and the backlight brightness controller 12 may specifically be a signal circuit structure as shown in fig. 4, where the buffer D1 is used as a receiver, and is used to receive the signal transmitted from the transmission line and then send the signal directly, for example, the signal sent from DCON is sent to the first LED driving chip 14 first, and then is sent to the second LED driving chip 14 through the buffer D1 of the first LED driving chip 14. Buffer D2 also serves as a receiver for receiving signals on DB and DC, respectively, while buffer D3 and transistor Q together form a signal transmitter that can support digital control circuit 122 to transmit signals on DC, such as feedback operating conditions, etc.
DC can be considered as a signal bus with an open drain output, on which DCON and all LED driver chips 14 can signal and receive signals. Fig. 4 shows a schematic connection relationship between the dual transmission lines and each circuit unit portion inside the backlight brightness controller 12, which can avoid increasing the complexity of the circuit structure while improving the circuit reliability and reducing the circuit production cost.
In one embodiment, as shown in fig. 4, the LED driving 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 the signal on the high-speed unidirectional transmission line DB through the buffer D2, the digital control circuit 142 receives the signal on the low-speed bidirectional transmission line DC through the buffer D4, the digital control circuit 142 transmits the signal to the low-speed bidirectional transmission line DC through the signal transmitter, and the buffer D1 is used for receiving the signal on the high-speed unidirectional transmission line DB and forwarding to the LED driving chip 14 of the next stage. The signal transmitter includes a buffer D3 and a transistor Q, an input end of the buffer D3 is connected to the digital control circuit 142, an output end of the buffer D3 is connected to a gate of the transistor Q, a drain of the transistor Q is connected to the low-speed bidirectional transmission line DC, and a source of the transistor Q is grounded.
It will be appreciated that in the above embodiments, the connection structure between the specific signal transmission lines of DB and DC and the LED driving chip 14 may be variously selected as long as the desired communication function can be achieved. In this embodiment, preferably, the circuit structure between DB and DC and the LED driving chips 14 may specifically be a signal circuit structure as shown in fig. 4, where the buffer D1 is used as a receiver, and is used to receive the signal sent from the transmission line DB and send the signal to the first LED driving chip 14 as it is, for example, the signal sent from the DCON is sent to the second LED driving chip 14 through the buffer D1 of the first LED driving chip 14, and so on. The buffer D2 in the LED driving chip 14 also serves as a receiver for receiving the signal on DB, and the buffer D3 and the transistor Q together form a signal transmitter, which can support the digital control circuit 142 to send a signal on DC, such as feedback operation status. The buffer D4 in the LED driver chip 14 also acts as a receiver for the signal on DC. DC is a bus mode of an open drain output, and DC is high when DCON and all LED driver chips 14 are not active (i.e., turning off transistor Q), and DC is low when DCON or any LED driver chip 14 is active (i.e., turning on transistor Q).
Fig. 4 shows a schematic connection relationship between the dual transmission lines and each circuit unit part inside the LED driving chip 14, where the resistor R is a pull-up resistor on the open drain output bus, and the circuit structure can avoid increasing the complexity of the circuit structure, further improve the circuit reliability and reduce the circuit production cost. In fig. 4, an arrow on a transmission line indicates a data transmission direction. The specific types of the buffer D1, the buffer D2, the buffer D3, the buffer D4, and the transistor Q may be determined according to the circuit specification parameters of the backlight control circuit system of a specific application, so long as the circuit can be used to implement the required communication line function.
In one embodiment, a display device is further provided, including a Mini LED unit board and the Mini LED backlight control circuit 100 described above, where the Mini LED unit board includes a plurality of Mini LED partitions.
It will be understood that, regarding the description limitation of the Mini LED backlight control circuit 100 in this embodiment, the description limitation in each embodiment of the Mini LED backlight control circuit 100 may be referred to in the same manner, and will not be repeated here. Those skilled in the art will understand that the display device herein may further include other circuit structures besides the Mini LED unit board and the Mini LED backlight control circuit 100 described above, and specifically, the structural components of the Mini LED display device in the art may be referred to in the same manner, which will not be described in detail in this specification.
By applying the Mini LED backlight control circuit 100, the display device adopts a double-wire transmission communication mode in backlight control, and effectively realizes the efficient signal transmission from DCON to LED driving chips on a single-layer PCB or a glass substrate. The state of the current LED driving chip can be fed back in real time while each frame of backlight data is transmitted, the complex requirement of the system application is supported, and the clock of the LED driving chip can be calibrated, so that the control of the LED driving chip is adjusted, the two lines are in full-time coordination, different channel coding modes are supported, the design of a more complex backlight system can be supported in an expandable mode, and the technical effect of high adaptability is achieved. The technology can be correspondingly converted into a Mini LED backlight control interface protocol with double-line transmission for popularization and application, so that the standardization of high backlight control performance of Mini LED display equipment is promoted.
In one embodiment, as shown in fig. 5, a Mini LED backlight control method is further provided, and the Mini LED backlight control method can be applied to a Mini LED backlight control circuit, wherein the circuit comprises a backlight brightness controller and N LED driving chips, each control channel of the backlight brightness controller adopts a pair of transmission lines to connect each LED driving chip governed by the channel, the LED driving chips are used for driving the governed Mini LED partitions, N is a positive integer not limited to 2, and each pair of transmission lines comprises a high-speed unidirectional transmission line and a low-speed bidirectional transmission line. The method may include the following control steps:
S12, the backlight brightness controller respectively sends reset signals to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line after the circuit is powered on, wherein the reset signals are used for indicating each LED driving chip to carry out reset operation;
S14, after resetting each LED driving chip, the backlight brightness controller sends an initialization command to the low-speed bidirectional transmission line, wherein the initialization command is used for indicating each LED driving chip to perform initialization operation;
S16, after initializing each initialized LED driving chip, the backlight brightness controller carries out address assignment on each LED driving chip on the path through a high-speed unidirectional transmission line;
And S18, after the address assignment is completed, the backlight brightness controller transmits a backlight control data packet to each LED driving chip on the path through a high-speed unidirectional transmission line at each frame time of the image, and reads the working state of the appointed LED driving chip on the path through a low-speed bidirectional transmission line, wherein the backlight control data packet is used for indicating each LED driving chip to drive the managed Mini LED partition to carry out backlight adjustment.
It will be appreciated that, with respect to the specific explanation of the backlight luminance controller, the LED driving chip, the high-speed unidirectional transmission line, and the low-speed bidirectional transmission line of the LED backlight control circuit in this embodiment, the same explanation as in the respective embodiments of the LED backlight control circuit 100 described above will be understood, and the description will not be repeated here.
According to the Mini LED backlight control method, a double-line transmission communication mode is adopted between the backlight brightness controller and the LED driving chips, namely, double-line transmission communication of a high-speed unidirectional transmission line and a low-speed bidirectional transmission line is adopted for each control channel of the backlight brightness controller, the high-speed unidirectional transmission line is used for transmitting backlight control data packets and carrying out address assignment on the LED driving chips on the channels, the low-speed bidirectional transmission line is used for initializing the channels, state feedback of the LED driving chips and on-line clock calibration are adopted, so that the required Mini LED backlight control function is realized, and efficient signal transmission from DCON (direct current on) on a single-layer PCB (printed circuit board) or a glass substrate to the LED driving chips is effectively realized. The state of the current LED driving chip can be fed back in real time while each frame of backlight data is transmitted, the complex requirement of the system application is supported, and the clock of the LED driving chip can be calibrated, so that the control of the LED driving chip is adjusted, the two lines are in full-time coordination, different channel coding modes are supported, the design of a more complex backlight system can be supported in an expandable mode, and the technical effect of high adaptability is achieved.
In one embodiment, as shown in fig. 6, the above method may further include the following control steps:
And before or after the set calibration time node reads the working state of the designated LED driving chip, the backlight brightness controller sends clock signals for setting the coding rule to each LED driving chip on the path through a low-speed bidirectional transmission line, wherein the clock signals are used for indicating each LED driving chip to perform online clock calibration by taking the clock signals as reference clocks, and the calibration time node comprises a set single calibration time point, a time point when each frame of image processing is completed or a time point when each M frame of image processing is completed, and M is a positive integer not less than 2.
In one embodiment, as shown in fig. 6, the method may further include a control step of the backlight brightness controller transmitting a reset signal to the high-speed unidirectional transmission line and the low-speed bidirectional transmission line, respectively, when an abnormality occurs in the backlight brightness controller or the LED driving chip.
In one embodiment, the process of performing address assignment on each LED driving chip on the path by the backlight brightness controller through the high-speed unidirectional transmission line specifically includes the following steps:
The backlight brightness controller sends a closing instruction on the high-speed unidirectional transmission line, wherein the closing instruction is used for indicating all LED driving chips on the passage to close 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, wherein the address assignment instruction is used for indicating a first LED driving chip on a channel to carry out address assignment, and the opening instruction is used for indicating the first LED driving chip to open the high-speed unidirectional transmission line for output after assignment;
and the backlight brightness controller circularly sends an address assignment instruction and an opening instruction on the high-speed unidirectional transmission line after the first LED driving chip finishes address assignment and opens the high-speed unidirectional transmission line for output until the address assignment of all the other LED driving chips on the path is finished.
For a specific explanation of each additional step or sub-step of the Mini LED backlight control method, reference may be made to the explanation of the corresponding operation procedure in each embodiment of the LED backlight control circuit 100, which is understood in the same manner and will not be repeated here.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The foregoing examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it is possible for those skilled in the art to make several variations and modifications without departing from the spirit of the present application, which fall within the protection scope of the present application. The scope of the application is therefore intended to be covered by the appended claims.
Claims (10)
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| TWI841295B (en) * | 2023-03-15 | 2024-05-01 | 瑞鼎科技股份有限公司 | Micro light-emitting diode display system |
| CN116743705B (en) * | 2023-06-15 | 2023-12-05 | 北京显芯科技有限公司 | Address configuration method, backlight control device and display device |
| TWI867779B (en) * | 2023-10-04 | 2024-12-21 | 瑞鼎科技股份有限公司 | Micro light-emitting diode display apparatus |
| CN118430464B (en) * | 2024-05-31 | 2025-02-25 | 北京显芯科技有限公司 | Instruction processing method, controller, backlight driver and display device |
| CN118711541B (en) * | 2024-08-07 | 2025-05-30 | 北京显芯科技有限公司 | Driving method of backlight unit and display apparatus |
| CN119207294B (en) * | 2024-10-28 | 2025-08-08 | 北京芯格诺微电子有限公司 | LED driving system and driving method |
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| CN111818284A (en) * | 2020-07-08 | 2020-10-23 | 康佳集团股份有限公司 | Regional dimming system and method for ultra-high-definition television |
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