Backlight driving method, backlight control constant current board and restart method, display module

Abstract

Embodiments of the present application provide a backlight driving method, a backlight control constant current board and a restart method, and a display module. The driving method comprises: obtaining a picture gray scale brightness of each display partition corresponding to a backlight module; determining a frequency of a pulse width modulation signal for driving each backlight module according to the picture gray scale brightness of each display partition; wherein when the picture gray scale brightness represents that the display partition is used to display a high gray scale brightness picture, the frequency of the pulse width modulation signal of the backlight module corresponding to the display partition is a first preset frequency; when the picture gray scale brightness represents that the display partition is used to display a low gray scale brightness picture, the frequency of the pulse width modulation signal of the backlight module corresponding to the display partition is a second preset frequency; the first preset frequency is higher than the second preset frequency; and each backlight module is driven to emit light according to the frequency of the pulse width modulation signal. According to the technology of the present application, the display effect of the display panel can be avoided from being affected by uneven brightness.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a backlight driving method, a backlight control constant current plate and restart method, and a display module. Background Technology

[0002] In related technologies, the backlight control constant current board usually uses the pulse width modulation (PWM) signal output by the backlight driver module for dimming. Since the backlight will turn on and off quickly when the duty cycle of the pulse width modulation signal is not 100%, the charging rate will be different in different areas of the panel due to the different characteristics of the panel under illumination and without illumination, resulting in a regular waterfall phenomenon on the screen display. Summary of the Invention

[0003] This application provides a backlight driving method, a backlight control constant current board and restart method, and a display module to solve or alleviate one or more technical problems in the related art.

[0004] As a first aspect of this application, this application provides a backlight driving method for a display module. The backlight includes multiple backlight modules corresponding one-to-one with multiple display zones of a display panel. The driving method includes: acquiring the grayscale brightness of the display zone corresponding to each backlight module; determining the frequency of a pulse width modulation signal for driving each backlight module based on the grayscale brightness of each display zone; wherein, when the grayscale brightness indicates that the display zone is used to display a high grayscale brightness image, the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is a first preset frequency; when the grayscale brightness indicates that the display zone is used to display a low grayscale brightness image, the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is a second preset frequency; the first preset frequency is higher than the second preset frequency; and driving each backlight module to emit light according to the frequency of the pulse width modulation signal.

[0005] In one embodiment, the first preset frequency is greater than or equal to 10 times the refresh rate of the display panel; and / or, the first preset frequency is not less than 1 kHz.

[0006] In one embodiment, the second preset frequency is an integer multiple of the display panel refresh rate and less than 10 times the display panel refresh rate.

[0007] In one embodiment, determining the frequency of the pulse width modulation signal used to drive each backlight module based on the grayscale brightness of each display partition includes: comparing the grayscale brightness represented by the grayscale brightness of each display partition with a grayscale brightness threshold; when the grayscale brightness represented by the grayscale brightness is higher than or equal to the grayscale brightness threshold, determining that the display partition is used to display a high grayscale brightness image, and determining that the frequency of the pulse width modulation signal of the backlight module corresponding to the display partition is a first preset frequency; or, when the grayscale brightness represented by the grayscale brightness is lower than the grayscale brightness threshold, determining that the display partition is used to display a low grayscale brightness image, and determining that the frequency of the pulse width modulation signal of the backlight module corresponding to the display partition is a second preset frequency.

[0008] As a second aspect of the embodiments of this application, this application provides a method for restarting a backlight control constant current board. The backlight control constant current board includes a step-down module for stepping down the input voltage to the backlight operating voltage, a driving module for driving the backlight, and a control module. The method includes: acquiring the voltage output state of the step-down module and the current output state of the driving module; determining whether an abnormal situation has occurred based on the voltage output state of the step-down module or the current output state of the driving module; in response to the determination result being an abnormal situation, turning off the input voltage of the step-down module and starting a timer; in response to the timer duration reaching a preset delay duration, turning on the input voltage of the step-down module to restart the step-down module and updating the restart count of the step-down module; when the restart count reaches a preset number, controlling the input voltage of the step-down module to remain in the off state.

[0009] In one implementation, the preset delay duration is greater than or equal to 1 second and less than or equal to 3 seconds; and / or, the preset number of times is greater than or equal to 2 times and less than or equal to 4 times.

[0010] In one implementation, determining whether an abnormal situation has occurred based on the voltage output status of the buck module includes: performing voltage divider sampling on the output voltage of the buck module to obtain the status flag bit corresponding to the buck module; when the level represented by the status flag bit is low, it is determined that the output of the buck module is abnormal.

[0011] In one implementation, determining whether an abnormal situation has occurred based on the current output state of the drive module includes: when the output current of the drive module does not conform to the preset current range, determining that the output of the drive module is abnormal.

[0012] In one embodiment, the method further includes: storing the voltage output state of the step-down module and the current output state of the drive module in a preset data format to a register, and reporting the stored data corresponding to the voltage output state and current output state stored in the register to the control chip of the display module through a serial communication protocol.

[0013] As a third aspect of the embodiments of this application, the embodiments of this application provide a backlight control constant current board, including a step-down module for stepping down the input voltage to the backlight operating voltage, a driving module for driving the backlight, and a control module, wherein the control module is used to execute the method in any of the above embodiments.

[0014] In one embodiment, the system further includes an input switch circuit for providing an input voltage to the input terminal of the buck module. The input switch circuit is communicatively connected to a control module, wherein the control module is configured to control the input switch circuit to turn on or off the input voltage provided to the buck module.

[0015] In one embodiment, the input switching circuit includes a MOSFET and a transistor. The MOSFET is connected in series between the voltage input terminal and the input terminal of the buck module. The control terminal of the transistor is communicatively connected to the control module. The output terminal of the transistor is connected to the gate of the MOSFET, so that the control module controls the conduction and cutoff of the transistor to turn the MOSFET on and off.

[0016] In one embodiment, a communication interface is also included for connecting to a control board of the display module. The communication interface is used to receive integrated first and second functional signals from the control board. The first functional signal is used to control the backlight control constant current board to drive the backlight source to turn on and off as a whole, and the second functional signal is used to control the overall brightness of the backlight source driven by the backlight control constant current board.

[0017] As a fourth aspect of the embodiments of this application, the embodiments of this application provide a display module, characterized in that it includes: a display panel having a plurality of display zones in its display area; a backlight including backlight modules corresponding one-to-one with the plurality of display zones; and a backlight control constant current plate as in any of the above embodiments.

[0018] The backlight driving method of this application embodiment, by adopting the above technical solution, adjusts the frequency of the pulse width modulation signal of the corresponding backlight module according to the grayscale brightness of the current display partition, which can improve the brightness uniformity of the display screen, improve the balance of the bright and dark distribution of the display screen, and thus effectively suppress and improve the effect of water ripple phenomenon, and avoid uneven brightness affecting the display effect of the display panel.

[0019] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of this application will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0020] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0021] Figure 1 A schematic diagram illustrating the water ripple phenomenon in related technologies is shown.

[0022] Figure 2 A schematic diagram illustrating the relationship between the width of horizontal stripes in related technologies is shown.

[0023] Figure 3 A wiring diagram of a backlight module according to an embodiment of this application is shown.

[0024] Figure 4 A schematic diagram illustrating the capacitance-resistance difference according to an embodiment of this application is shown.

[0025] Figure 5 A flowchart illustrating a backlight driving method for a display module according to an embodiment of this application is shown.

[0026] Figure 6 A flowchart illustrating a backlight driving method for a display module according to a specific example of Embodiment 1 of this application is shown.

[0027] Figure 7 A schematic diagram of a backlight control constant current plate according to an embodiment of this application is shown.

[0028] Figure 8 A buck topology diagram according to an embodiment of this application is shown.

[0029] Figure 9A A flowchart illustrating a method for restarting a backlight control constant current board according to an embodiment of this application is shown.

[0030] Figure 9B A flowchart illustrating a method for restarting a backlight control constant current board according to a specific example of an embodiment of this application is shown.

[0031] Figure 10 A schematic diagram of a voltage divider circuit according to an embodiment of this application is shown.

[0032] Figure 11 A schematic diagram of an input switch circuit according to an embodiment of this application is shown.

[0033] Figure 12 A schematic diagram of the I2C communication protocol according to an embodiment of this application is shown.

[0034] Figure 13 The output pin mapping table of the backlight control constant current board of the related technology is shown.

[0035] Figure 14 A wiring diagram of a backlight control constant current board according to an embodiment of this application is shown.

[0036] Explanation of reference numerals in the attached figures:

[0037] 10-Driver module; 20-Control module; 30-Step-down module; 40-Backlight module; 50-Inductor; 60-Load resistor; 70-Output capacitor; 80-Diode; 90-Input capacitor; 100-Switching transistor; 110-Second input terminal; 120-Transistor; 130-MOSFET; 140-Output terminal; 150-Voltage input terminal; 160-Input switching circuit; 170-Communication interface; 180-Control board. Detailed Implementation

[0038] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0039] In related technologies, the backlight of a liquid crystal display panel is typically adjusted using a pulse width modulation signal output from a light-emitting diode driver (LED driver). For example... Figure 1 As shown, when the duty cycle of the pulse width modulation signal is not 100%, the backlight will turn on and off. The difference in charging rate between the illuminated and unilluminated areas of the display panel will cause regular alternating bright and dark horizontal lines on the screen, i.e., the water ripple phenomenon.

[0040] like Figure 2 As shown, the width of the horizontal bars is related to the pulse width modulation (PWM) signal output by the LED driver. A larger duty cycle in the PWM signal results in narrower bars, while a smaller duty cycle results in wider bars. The number of bars is related to the frequency of the PWM signal output by the LED driver and the refresh rate of the display panel. For example, when the frequency of the PWM signal output by the backlight driver module is 300Hz and the refresh rate of the display panel is 60Hz, 10 alternating bright and dark horizontal bars will appear on the panel; conversely, when the frequency of the PWM signal output by the backlight driver module is 180Hz and the refresh rate of the display panel is 60Hz, 6 alternating bright and dark horizontal bars will appear on the display panel.

[0041] It is understandable that the pulse width modulation signal output by the backlight driver module 10 is essentially a square wave signal that switches rapidly between high and low levels. For example... Figure 3As shown, the backlight consists of multiple common-anode light-emitting diodes (LEDs). When the duty cycle increases (i.e., the proportion of high level in the entire cycle increases), the LEDs remain in the conducting state for a longer period within a single cycle, thus increasing the backlight brightness; conversely, when the duty cycle decreases, the LEDs remain in the conducting state for a shorter period within a single cycle, thus decreasing the backlight brightness. Here, a single cycle of the pulse width modulation signal refers to the duration of one high-low level switch, and the frequency of the pulse width modulation signal refers to the number of high-low level switches that can occur within one cycle.

[0042] It's understandable that the principle behind a display panel's illumination is the charging of each pixel unit by the internal driving circuitry. Once a pixel unit is charged, its degree of charging, or charging rate, directly affects its light-emitting state, thus determining the display panel's brightness. Within the display panel, the charging status of each pixel unit is closely related to its internal capacitance and resistance values ​​(i.e., RC values), which determine the charging speed. Because display panels are typically made of semiconductor materials, and backlighting conditions vary across different areas, the semiconductor characteristics of backlit areas differ from those of unlit areas, resulting in differences in RC values ​​and consequently, different charging rates for pixel units in each area. Figure 4 As shown, specifically, the data signal layer experiences data delay when illuminated, causing the conductivity of the backlit and unlit areas of the display panel to differ, resulting in RC delay. Consequently, the time required for pixel units in different areas of the display panel to reach the same brightness varies. In other words, when there are significant differences in the charging rates of different areas, the brightness distribution of the display panel will be uneven, resulting in a water ripple effect with alternating bright and dark areas.

[0043] To address the aforementioned shortcomings, this application provides a backlight driving method for a display module. This method controls the frequency of the pulse width modulation signal output by the backlight driving module according to the grayscale brightness of the display partition, thereby improving the water ripple phenomenon and enhancing the uniformity of brightness and overall display quality of the display panel.

[0044] In this embodiment, the execution entity of the backlight driving method for the display module can be the control module of the backlight control constant current board. For example... Figure 5 As shown, the backlight driving method for this display module may include the following steps:

[0045] S101: Obtain the grayscale brightness of the display zone corresponding to each backlight module;

[0046] S102: Determine the frequency of the pulse width modulation signal used to drive each backlight module based on the grayscale brightness of each display zone;

[0047] Specifically, when the grayscale brightness of the display zone is used to display a high grayscale brightness image, the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is a first preset frequency; when the grayscale brightness of the display zone is used to display a low grayscale brightness image, the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is a second preset frequency; the first preset frequency is higher than the second preset frequency.

[0048] S103: Drives each backlight module to emit light according to the frequency of the pulse width modulation signal.

[0049] For example, the display module includes a display panel, a backlight, and a control board. The display panel can be a Liquid Crystal Display (LCD) or an Electronic Ink Display Panel / Electronic Ink Display (EPD), etc. The control board may include a Timing Controller (TCON) and a Power Management Integrated Circuit (PMIC). The backlight includes multiple backlight modules corresponding one-to-one with multiple display zones of the display panel, and each backlight module may include at least one Light-Emitting Diode (LED). Gray-level brightness refers to the brightness value of the display module under different gray-level conditions. The gray-level brightness threshold range is typically 0~255, where gray level 0 represents the lowest brightness and gray level 255 represents the highest brightness.

[0050] In this embodiment, for display zones identified as having high grayscale brightness, the pulse width modulation signal of the corresponding backlight module is switched to a first preset frequency. The first preset frequency can be greater than or equal to a preset multiple of the display panel refresh rate, so that within one display panel refresh cycle (i.e., the time window for a pixel unit to complete one charge), the backlight module will complete multiple complete on / off cycles. Under this condition, the backlight illumination duration and backlight off duration corresponding to each pixel unit charge are compressed proportionally, and the cumulative time of the pixel unit in both backlit and unlit states tends to be balanced, significantly reducing the RC value difference caused by the difference in semiconductor characteristics. The reduction in RC value difference means that the charging rate of the pixel unit in different states tends to be consistent, thereby making the charging rate distribution in each area of ​​the display panel more uniform, and effectively suppressing the water ripple phenomenon of alternating bright and dark areas. It should be noted that in high grayscale brightness scenes, the overall backlight brightness is relatively high. If a low-frequency pulse width modulation signal is used, the contrast between the bright and dark areas of the horizontal stripes will be more obvious and the visual visibility will be stronger. However, after switching to a high frequency, the horizontal stripes are effectively eliminated, and the improvement in display quality of high grayscale brightness scenes is the most significant.

[0051] For display zones identified as having low grayscale brightness, the pulse width modulation signal of the corresponding backlight module is maintained at a second preset frequency. Since the backlight duty cycle of low grayscale brightness images is inherently small, the overall backlight brightness is low. Even if a certain degree of water ripple effect exists, the absolute brightness difference between bright and dark horizontal lines is limited, and the human eye's sensitivity to these lines is correspondingly reduced. Therefore, the impact of this phenomenon on the actual display effect is within an acceptable range. Thus, retaining the second preset frequency for low grayscale brightness zones ensures display quality while maintaining backlight drive stability, avoiding unnecessary power consumption from frequency switching.

[0052] In summary, the backlight driving method of the display module in this application applies a pulse width modulation signal frequency adapted to the display characteristics of different brightness zones by using a grayscale brightness threshold as the judgment criterion. In the high grayscale brightness area, the high frequency suppresses the conditions for the generation of water ripple phenomenon from the source, while the low frequency takes into account driving stability in the low grayscale brightness area. As a result, the uniformity of display brightness is improved as a whole, and the visual display effect of the display panel is effectively improved.

[0053] In one embodiment, the first preset frequency is greater than or equal to 10 times the refresh rate of the display panel, and / or the first preset frequency is not less than 1KHz.

[0054] For example, when the refresh rate of the display panel is F0, the first preset frequency F1 should satisfy: F1 ≥ 10 * F0 or F1 ≥ 1 kHz, or even both conditions simultaneously.

[0055] For example, taking a display panel refresh rate of 60Hz as an example, the first preset frequency should be at least higher than 600Hz, while taking into account the requirement of not less than 1KHz. The final first preset frequency can be selected in the range of 1KHz or higher to ensure that the backlight module changes on and off quickly enough, thereby avoiding visual flicker and improving the stability and visual comfort of the display screen.

[0056] In one embodiment, the second preset frequency is an integer multiple of the display panel refresh rate and less than 10 times the display panel refresh rate.

[0057] For example, when the refresh rate of the display panel is F0, the second preset frequency F2 must simultaneously meet the following two conditions: First, F2 is an integer multiple of F, i.e., F2 = N × F0, where N is a positive integer; second, F2 is less than 10 times the refresh rate of the display panel, i.e., F2 < 10 F0. Therefore, the range of the integer multiple N is 1 ≤ N ≤ 9. Taking a display panel refresh rate of 60Hz as an example, the selectable values ​​for the second preset frequency include a series of frequency levels such as 60Hz (N=1), 120Hz (N=2), 180Hz (N=3)...540Hz (N=9). In practical applications, the frequency can be flexibly selected within the above range according to the dimming accuracy requirements of the specific project and the support capabilities of the driver chip.

[0058] By setting the second preset frequency to an integer multiple of the display panel's refresh rate, the backlight module completes an integer number of full pulse width modulation (PWM) on / off cycles within each refresh cycle of the display panel. This means that a strict synchronization relationship is formed between the backlight's on / off rhythm and the pixel unit's charging / discharging rhythm. Specifically, the backlight illumination time distribution corresponding to each frame remains fixed on the time axis, preventing the accumulation of backlight phase shifts between adjacent frames. If the second preset frequency is not an integer multiple of the refresh rate, the backlight phase corresponding to the starting moment of pixel unit charging in each frame will drift frame by frame, causing dynamic changes in the charging rate difference between different frames. Visually, this manifests as periodic fluctuations in the position or width of horizontal lines over time, introducing additional flicker and degrading display stability. When the second preset frequency is an integer multiple of the refresh rate, the aforementioned phase drift problem is fundamentally eliminated. The distribution of horizontal lines (if present) remains stable over time, and the visual perception tends to be static, effectively avoiding dynamic flicker interference caused by non-integer multiple relationships. Furthermore, by limiting the second preset frequency to less than 10 times the display panel refresh rate, on the one hand, this upper limit constraint clearly distinguishes the second preset frequency from the first preset frequency (the first preset frequency is greater than or equal to 10 times the refresh rate), creating a clear boundary between the two frequency levels and avoiding control logic ambiguity caused by frequency level overlap near the threshold. On the other hand, in low grayscale brightness conditions, the backlight duty cycle is inherently small. If the pulse width modulation frequency is increased to a high-frequency range close to or exceeding 10 times the refresh rate, the driver chip needs to complete the current establishment and shutdown in a very short time while maintaining the same brightness output, placing higher demands on the response speed of the driver circuit. This may also cause actual duty cycle distortion due to insufficient steepness of the current rise / fall edge, thus affecting the brightness control accuracy. Limiting the second preset frequency to less than 10 times the refresh rate allows the driver circuit to operate within its sufficient frequency range in low grayscale brightness conditions, ensuring the stability of current output and the accuracy of brightness adjustment. It also correspondingly reduces the switching losses of the backlight driver module under low brightness conditions, which is beneficial to the optimization of overall power consumption.

[0059] In one embodiment, step S102 may specifically include:

[0060] The grayscale brightness represented by the grayscale brightness of each display zone is compared with the grayscale brightness threshold.

[0061] When the grayscale brightness represented by the grayscale brightness of the screen is higher than or equal to the grayscale brightness threshold, the display zone is determined to be used to display a high grayscale brightness screen, and the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is determined to be the first preset frequency.

[0062] Alternatively, when the grayscale brightness represented by the grayscale brightness of the screen is lower than the grayscale brightness threshold, the display zone is determined to be used to display the low grayscale brightness screen, and the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is determined to be the second preset frequency.

[0063] Among them, the gray level brightness threshold can be the tenth gray level.

[0064] The backlight driving method of the display module in this application is described below with a specific example, such as Figure 6 As shown, the driving method may include the following steps:

[0065] S201: Receives grayscale brightness data of the display zones from the control board of the display module;

[0066] S202: Determine whether the grayscale brightness of the display zone is greater than L10;

[0067] S203: If the grayscale brightness of the screen is not greater than L10, the display zone is set to low brightness and a pulse width modulation signal of the second preset frequency is output.

[0068] S204: If the grayscale brightness of the screen is greater than L10, the display zone will be set to high brightness and a pulse width modulation signal of the first preset frequency will be output.

[0069] The control module receives pulse width modulation (PWM) signals, BLON signals, and the grayscale brightness of the current display zone from the TCON output of the control board of the display module. The grayscale brightness threshold can be set to the tenth grayscale level. The grayscale brightness of the current display zone is compared with the brightness of the tenth grayscale level. If the grayscale brightness of the current display zone is greater than the brightness of the tenth grayscale level, the control module determines that the display zone is used to display a high grayscale brightness image and controls the backlight driver module to output a high-frequency (i.e., a first preset frequency) PWM signal. If the grayscale brightness of the current display zone is not greater than the brightness of the tenth grayscale level, the control module determines that the display zone is used to display a low grayscale brightness image and controls the backlight driver module to output a low-frequency (i.e., a second preset frequency) PWM signal. By outputting PWM signals of different frequencies for high and low grayscale brightness, the brightness uniformity of the displayed image can be improved, thereby effectively reducing the water ripple effect.

[0070] As another embodiment of this application, this application also provides a method for restarting a backlight control constant current plate. For example... Figure 7 As shown, the backlight control constant current board includes a step-down module 30 for stepping down the input voltage to the backlight operating voltage, a drive module 10 for driving the backlight, and a control module 20. The control module 20 can also be used to execute the backlight driving method of the above embodiments of this application.

[0071] For example, the driving module 10 can be a light-emitting diode driver (LED driver), mainly used to send pulse width modulation signals to the backlight module of the backlight under the control of the control module 20 to drive and dim the backlight. The control module 20 can be a microcontroller unit (MCU), mainly used to receive the grayscale brightness data of each display zone sent by the control board 180 of the display module, convert the brightness of different display zones into the brightness data of the corresponding local dimming (LD) zones, and transmit control signals to different driving modules 10 according to the brightness data, adjust the duty cycle of the pulse width modulation signal output by the driving module 10, and adjust the brightness of the backlight of the corresponding bright and dark zones to make the brightness of the display uniform. The buck module 30 can be a buck converter integrated circuit (Buck IC), mainly used to convert the input 24V operating voltage into the operating voltage of the LED, thereby lighting the backlight.

[0072] In some embodiments of this application, the buck module 30 primarily utilizes a Buck circuit for voltage reduction. For example... Figure 8 As shown, the buck module 30 mainly achieves input voltage reduction by switching transistor 100 on and off. When transistor 100 is on and diode 80 is off, the input power supply Vi provides current to the load resistor 60, and also provides current storage capacity for inductor 50 and output capacitor 70. Inductor 50 will offset part of the power supply voltage, and the voltage across the load resistor 60 is lower than the power supply voltage. When transistor 100 is off and diode 80 is forward conducting, the input voltage Vi cannot supply power to the load resistor 60. Inductor 50 provides current to the load resistor 60, and output capacitor 70 provides voltage to the load resistor 60. In a short time, the inductor voltage drops, and the voltage across the load resistor 60 drops, thus achieving a low output voltage from the Buck circuit. Input capacitor 90 is used for filtering, making the input power supply Vi more stable, and also providing transient current when the current of the load resistor 60 changes.

[0073] It is understandable that the step-down module 30 is susceptible to damage from external environmental factors such as circuit malfunctions and electrostatic discharge in practical applications. Therefore, the step-down module 30 is usually equipped with multiple protection mechanisms, such as high current protection and low voltage protection, to automatically cut off the output in abnormal situations and protect the safety of the circuit and load.

[0074] Based on the aforementioned protection mechanism, during the assembly of the backlight control constant current board, external electrostatic interference may trigger the protection mechanism of the buck module 30, causing its output to be interrupted. Once the buck module 30 stops outputting, the backlight control constant current board will be unable to provide power to the backlight module 40, resulting in the backlight going out and ultimately causing the display panel to display a black screen. It should be noted that this situation is not due to a fault in the buck module 30 itself, but rather to its protection mechanism actively cutting off the output. Therefore, when this type of black screen phenomenon occurs, simply restarting the backlight control constant current board will restore the backlight output and display image; there is no need to replace or repair the buck module 30.

[0075] It should be noted that when the buck module 30 experiences output abnormalities due to a short circuit or external environmental factors, restarting the backlight control constant current board will not resolve the issue. Furthermore, if the output abnormality is caused by other problems such as a short circuit, frequent restarts will cause irreversible damage to the control board 180. Therefore, if restarting the backlight control constant current board several times fails to resolve the output abnormality of the buck module 30, the control board 180 of the display module is deemed to have an unrecoverable fault, and the backlight control constant current board will no longer be restarted.

[0076] To further monitor the status of the backlight control constant current board, the signals from the backlight control constant current board are first classified into the power signal output by the buck module 30 and the current signal output by the driver module 10. In other words, monitoring only the output status of the buck module 30 and the driver module 10 is sufficient to monitor the status of the backlight control constant current board. Monitoring the voltage output status of the buck module 30 enables monitoring of its output status, and monitoring the current output status of the driver module 10 enables monitoring of its output status.

[0077] like Figure 9A As shown, the restart method of the backlight control constant current board in this application embodiment includes the following steps:

[0078] S301: Obtain the voltage output status of the step-down module 30 and the current output status of the drive module 10;

[0079] S302: Determine whether an abnormal situation has occurred based on the voltage output status of the step-down module 30 or the current output status of the drive module 10;

[0080] S303: In response to the judgment result being an abnormal situation, the input voltage of the buck module 30 is turned off and the timing is started;

[0081] S304: In response to the timing duration reaching the preset delay duration, the input voltage of the buck module 30 is turned on to restart the buck module 30, and the restart count of the buck module 30 is updated;

[0082] S305: When the number of restarts reaches the preset number, the input voltage of the step-down module 30 is kept off.

[0083] In one implementation, the preset delay duration can be any value between 1 second and 3 seconds; and / or, the preset number of times is greater than or equal to 2 times and less than or equal to 4 times.

[0084] For example, regarding steps S303 to S305, when the control module 20 detects an abnormality in the voltage output state of the buck module 30 or the current output state of the drive module 10, the control module 20 first outputs a control signal to turn off the input switch circuit 160, cutting off the input voltage of the buck module 30, and simultaneously starts the internal register timing. When the timing duration reaches the preset delay duration (e.g., 2 seconds), the control module 20 outputs a high-level control signal to turn the input switch circuit 160 back on, the input voltage is restored to be transmitted to the buck module 30, the buck module 30 completes initialization and resumes normal output, and the backlight control constant current board completes one restart. Each time a restart is completed, the internal counter of the control module 20 increments by one to update the restart count. When the number of restarts accumulated by the internal counter exceeds the preset number (e.g., 3 times), the control module 20 determines that the control board 180 of the display module has suffered an unrecoverable fault and stops performing the restart operation. The control module 20 continuously outputs a low-level signal to keep the input switch circuit 160 in the off state to prevent further damage to the control board 180 due to continuous abnormal restarts.

[0085] According to the restart method of the backlight control constant current board according to the embodiments of this application, on the one hand, it can achieve accurate identification and automatic response to abnormal states of the backlight control constant current board. Steps S301 and S302 simultaneously collect the voltage output state of the step-down module 30 and the current output state of the drive module 10, mapping the overall working state of the backlight control constant current board to two quantifiable signal dimensions. Compared with monitoring only a single signal, dual-channel parallel monitoring can cover a wider range of abnormal scenarios: voltage abnormalities of the step-down module 30 correspond to power supply side faults (such as protection mechanism triggering, external electrostatic discharge), and current abnormalities of the drive module 10 correspond to load side faults (such as LED string open circuits, short circuits). The two complement each other, effectively avoiding the risk of missed detection under a single monitoring dimension, and improving the comprehensiveness and reliability of abnormal identification.

[0086] On the other hand, a delayed restart mechanism effectively distinguishes between transient trigger protection and permanent hardware failure. Step S303 introduces a delay buffer stage that shuts off the input voltage and starts timing. In cases where the protection mechanism is triggered by occasional factors such as external electrostatic discharge or transient overcurrent, after the input voltage is cut off, the residual charge in the parasitic capacitance of the buck module 30 will be fully discharged during the delay period, and the internal state of the device will be completely reset, thereby eliminating the initial conditions for triggering protection. When the preset delay time ends, the input voltage is reconnected, and the buck module 30 can restart in the initial state and restore normal output. The delay time is set in the range of 1 to 3 seconds, which ensures the shortest time required for the internal state of the buck module 30 to be fully reset, and also avoids the backlight being off for too long due to excessive delay, thus affecting the user experience.

[0087] On the other hand, a limited-number restart mechanism avoids damage from cyclic restarts caused by hardware failures. Steps S304 and S305 introduce a restart count and upper limit constraint mechanism. When the output of the buck module 30 is interrupted due to the protection mechanism, it can usually restore normal output within a limited number of restart attempts. However, when the root cause is a hardware damage fault such as a short circuit, each restart cannot eliminate the root cause of the fault. In this case, continuous restarts are not only ineffective, but will also cause cumulative impact damage to the power management circuit and related components of the control board 180 due to repeated input voltage switching. The preset number of restarts is set in the range of 2 to 4 times. While giving sufficient recovery opportunities for transient faults, the number of ineffective restarts for hardware damage faults is limited to a reasonable range. This ensures the self-healing capability of the fault and achieves over-protection of the control board 180, extending the service life of the entire machine.

[0088] In summary, the restart method for the backlight control constant current board in this application embodiment, through the organic combination of dual-channel status monitoring, delayed buffer restart, and limited-number protection, achieves automatic recovery of transient anomalies of the backlight control constant current board without relying on external manual intervention. At the same time, it applies effective protection constraints to unrecoverable hardware failures, significantly improving the anti-interference capability of the backlight control constant current board and the overall reliability of the device.

[0089] The following describes the restart method of the backlight control constant current board according to an embodiment of this application using a specific example, such as... Figure 9B As shown, the restart method may include the following steps:

[0090] S401: Receives monitoring signals for the buck module;

[0091] S402: Determine if the buck module output is normal;

[0092] S403: If the output is normal, maintain the current operating state of the buck module:

[0093] S404: If the output is abnormal, the control signal will turn off the input switch circuit;

[0094] S405: The internal register times for 2 seconds, and the input switch circuit is re-energized;

[0095] S406: 24V input voltage is turned on, buck module restart complete;

[0096] S407: Internal counter restart count incremented by 1;

[0097] S408: Determine if the number of restarts is ≤3; if so, return to step S402.

[0098] S409: If not, completely shut down the input switch circuit; the control board of the display module needs repair.

[0099] Specifically, refer to Figure 11 The monitoring signal is used to monitor the voltage output status of the step-down module 30. Based on the monitoring signal, it is determined whether the voltage output status of the buck module 30 is normal. If the voltage output status of the buck module 30 is normal, there is no need to restart the control constant current board. If the voltage output status of the buck module 30 is abnormal, the input switch circuit 160 is turned off. When the internal register timer reaches 2s, the control module 20 outputs a high-level signal. At this time, the transistor 120 and MOSFET 130 in the input switch circuit 160 are turned on, thereby turning on the input switch circuit 160 and transmitting the input voltage to the buck module 30. The buck module 30 completes initialization, and the backlight control constant current board restarts. After the backlight control constant current board completes one restart, the internal counter increments by 1. When the number of times the internal counter accumulates, i.e., the number of times the backlight control constant current board restarts, is greater than 3, it is determined that the control board 180 has an unrecoverable fault problem, and the backlight control constant current board is no longer restarted. At this time, the control module 20 maintains a low-level output to ensure that the input switch circuit 160 does not conduct, preventing abnormalities.

[0100] Figure 10 A schematic diagram of a voltage divider circuit according to an embodiment of this application is shown. Figure 11 A schematic diagram of an input switch circuit according to an embodiment of this application is shown. In one embodiment, determining whether an abnormal situation has occurred based on the voltage output state of the step-down module 30 includes:

[0101] The output voltage of the step-down module 30 is sampled by voltage divider to obtain the status flag bit corresponding to the step-down module 30;

[0102] When the level represented by the status flag is low, it is determined that the output of the buck module 30 is abnormal.

[0103] For example, since the output voltage of the step-down module 30 is usually 18V, the general purpose input / output (GPIO) interface of the control module 20, i.e. the MCU, cannot carry the voltage output of its step-down module 30. Therefore, the output voltage of the step-down module 30 needs to be divided.

[0104] like Figure 10 As shown, by adding a series resistor in the circuit, the buck module 30 is divided, and its output voltage is controlled to be around 3.3V. This voltage is then set as a status flag, serving as a high-level indicator voltage. When the control module 20 receives a high level, it indicates that the buck module 30 output is normal and there is no abnormality. When the output of the buck module 30 is abnormal, the voltage at the voltage divider resistor is abnormally pulled low, resulting in a low voltage transmitted to the control module 20. In other words, the control module 20 receives a low level. At this time, the control module 20 determines that the buck module 30 output is abnormal and outputs a control signal to control the input and shutdown of the voltage input (VIN) signal.

[0105] For example, such as Figure 11 As shown, the input switch circuit 160 uses a combination of MOSFET 130 and transistor 120. The input switch circuit 160 has two input terminals, namely a voltage input terminal 150 and a second input terminal 110, and one output terminal, namely a first output terminal 140. The voltage input terminal 150 is connected to the power supply board to power the input switch circuit; the second input terminal 110 is communicatively connected to the control module 20 to provide control signals to the transistor 120; the first output terminal 140 is connected to the input terminal of the buck module 30 to provide voltage to the buck module 30.

[0106] When the buck module 30 outputs normally, the control module 20 outputs a high-level signal or a specific drive signal to the control terminal of the transistor 120. The transistor 120 then conducts, and its output terminal outputs a high-level signal to the gate of the MOSFET 130. The gate of the MOSFET 130 is in a high-level state, thus turning the MOSFET 130 on and connecting the voltage input terminal 150 and the first output terminal 140, supplying voltage to the backlight control constant current board and normally powering the buck module 30. When the buck module 30 outputs abnormally, the control module 20 outputs a low-level signal, the transistor 120 is cut off, the gate of the MOSFET 130 is in a low-level state, the MOSFET 130 is off, and the voltage input terminal 150 and the first output terminal 140 are disconnected. At this time, the power board no longer supplies power to the backlight control constant current board. The backlight control constant current board needs to be self-restarted. When the step-down module 30 has an output signal again, the control module 20 will output a high-level signal, the transistor 120 will be turned on, and then the MOSFET 130 will be turned on, connecting the voltage input terminal 150 and the first output terminal 140 to supply power to the step-down module 30, thereby realizing the restart method of the backlight control constant current board.

[0107] In one embodiment, determining whether an abnormal situation has occurred based on the current output state of the drive module 10 includes: when the output current of the drive module 10 does not meet the preset current range, determining that the output of the drive module 10 is abnormal.

[0108] For example, the control module 20 can monitor the current output status of the drive module 10 to achieve monitoring of the output status of the drive module 10. First, the output current of the drive module 10 is categorized into three abnormal states: excessive current, insufficient current, and no output current. Based on these three abnormal states, the control module 20 sets two preset current ranges: a high threshold current and a low threshold current. When the output current of the drive module 10 exceeds the high threshold current or falls below the low threshold current, the control module 20 determines that the drive module 10 is abnormal and initiates a self-restart procedure. If the self-restart procedure cannot restore the abnormal state, the control module 20 shuts off the power input to the drive module 10, thereby protecting both the drive module 10 and the backlight.

[0109] Figure 12 A schematic diagram of the I2C communication protocol according to an embodiment of this application is shown. Figure 12 As shown, in one embodiment, it further includes:

[0110] The voltage output status of the step-down module 30 and the current output status of the drive module 10 are stored in a register in a preset data format, and the stored data corresponding to the voltage output status and current output status stored in the register are reported to the control chip of the display module through a serial communication protocol.

[0111] For example, the voltage output state of the step-down module 30 and the current output state of the drive module 10 can be stored in a register in a preset data format to express an abnormal situation to the control board 180. Specifically, as shown in the example... Figure 12 As shown, the preset data format can include eight data formats, Bits 0 to 7. Different bits represent different meanings; for example, Bit 0 represents the Buck bit, Bit 1 represents the low current bit, Bit 2 represents the high current bit, Bit 3 represents the LED Driver bit, and Bits 4 to 7 represent reserved bits. Communication between the control board 180 and the backlight control constant current board can be achieved via the I2C protocol. The control board 180 can receive abnormal status data from the backlight control constant current board, thereby obtaining the abnormal state of the backlight control constant current board and enabling the detection and control of the backlight state.

[0112] As another aspect of the embodiments of this application, this application also provides a backlight control constant current plate. Figure 13 The output pin mapping table of the backlight control constant current board of the related technology is shown.

[0113] like Figure 13 As shown, the input of the backlight control constant current board in the related technology is mainly divided into two parts: one part is for grounding and power supply, and the other part is the control signal (Back Light ON, BLON) for controlling the backlight on and the pulse width modulation signal for controlling the overall brightness of the backlight. Specifically, pins 1-5 are used to receive power signals from the front-end power board to power the backlight control constant current board; pins 6 to 10, as well as pins 15 and 16, are used for grounding; pin 12 is used to control whether the backlight is on or off; and pin 13 is used to control the overall brightness of the backlight with a pulse width modulation signal. In addition to connecting the voltage signal from the power board to the backlight control constant current board, the BLON signal and the pulse width modulation signal also need to be connected from the control board 180 to the backlight control constant current board. At this time, the wiring of the backlight control constant current board is complicated, which is not conducive to the assembly and use of the whole machine.

[0114] like Figure 14 As shown, in one embodiment, the backlight control constant current board includes an input switch circuit 160 for providing an input voltage to the input terminal of the step-down module 30. The input switch circuit 160 is communicatively connected to the control module 20, wherein the control module 20 is configured to control the input switch circuit 160 to turn on or off the input voltage provided to the step-down module 30.

[0115] For example, such as Figure 11As shown, the input terminals of the input switch circuit 160 can be divided into a voltage input terminal 150 and a second input terminal 110, which are used to receive the positive and negative voltages from the power supply board and the control signals from the control module 20, respectively. The output terminal 140 is used to provide a stable step-down power signal to the backlight drive module 10. The step-down module can be a buck converter integrated circuit (Buck IC), whose input terminal is connected to the output terminal 140 of the input switch circuit 160, and is used to receive the voltage from the input switch circuit 160. The input switch circuit 160 is communicatively connected to the control module 20, and the control module 20 can output control signals to adjust the on or off state of the input switch circuit 160, thereby realizing the on / off control of the input voltage supplied to the step-down module 30.

[0116] In one embodiment, the input switch circuit 160 includes a MOSFET 130 and a transistor 120. The MOSFET 130 is connected in series between the voltage input terminal 150 and the input terminal of the buck module 30. The control terminal of the transistor 120 is communicatively connected to the control module 20. The output terminal of the transistor 120 is connected to the gate of the MOSFET 130, so that the control module 20 controls the conduction and cutoff of the transistor 120 to realize the switching on and off of the MOSFET 130.

[0117] For example, such as Figure 11 As shown, when the control module 20 outputs a high level or a specific drive signal to the control terminal of the transistor 120, the transistor 120 is turned on, and its output terminal provides a turn-on drive voltage to the gate of the MOSFET 130, thereby turning on the MOSFET 130 and allowing the input voltage to flow from the voltage input terminal 150 to the input terminal of the buck module 30. Conversely, when the control module 20 outputs a low level or a turn-off signal, the transistor 120 is turned off, and its output terminal no longer provides a drive voltage to the gate of the MOSFET 130, thus turning off the MOSFET 130, cutting off the transmission of the input voltage, and turning off the input terminal of the buck module 30.

[0118] Through the above implementation method, the instructions of the control module 20 can be responded to quickly, and efficient power supply control can be achieved. In addition, the driving method of the combination of transistor 120 and MOSFET 130 facilitates the integrated design and layout of the backlight control constant current board, and reduces the high drive current burden required for the control module 20 to directly control the MOSFET 130.

[0119] In one embodiment, the backlight control constant current board further includes a communication interface 170 for connecting to the control board 180 of the display module. The communication interface 170 is used to receive an integrated first function signal and a second function signal from the control board 180. The first function signal is used to control the backlight control constant current board to drive the overall opening and closing of the backlight source, and the second function signal is used to control the overall brightness of the backlight source driven by the backlight control constant current board.

[0120] For example, the control board 180 of the display module may include a timing controller (TCON) and a power management integrated circuit (PMIC). The PMIC manages and distributes the power supply to each functional module within the display module and outputs corresponding functional control signals according to system control requirements. For instance, in this embodiment, the first functional signal is a BLON signal used to control the backlight driving module 10 to turn on or off. The PMIC transmits the BLON signal to the timing controller. After receiving the BLON signal from the PMIC, the timing controller can combine the operating status of the display system and other control information to generate a second functional signal. In this embodiment, the second functional signal is a pulse width modulation signal used to adjust the overall brightness of the backlight. After integration and processing by the timing controller, the first and second functional signals, namely the BLON signal and the pulse width modulation signal, are transmitted through LED backlight fiber to the communication interface 170 of the backlight control constant current board. The LED backlight fiber is used to connect the control board 180 of the display module and the wire assembly of the backlight control constant current board.

[0121] Through the above implementation method, the control board 180 of the display module can transmit the pulse width modulation signal and the BLON signal to the backlight control constant current board in a coordinated manner, so as to realize the control of the backlight brightness and the switching state, optimize the wiring structure between the control board 180 of the display module and the backlight control constant current board, and save costs.

[0122] As a fourth aspect of this application, this application also provides a display module, including a display panel, a backlight, and the backlight control constant current plate described in the above embodiments. The display panel has multiple display zones, each of which may include several rows and columns of pixel units. The backlight includes backlight modules 40 corresponding to each of the multiple display zones. Each backlight module 40 can independently generate light output and can adjust its brightness according to the brightness requirements of that display zone.

[0123] For example, when the image content of a certain display zone is dark, the corresponding backlight module 40 can reduce the brightness or even turn it off to achieve local dimming (LD) and thus reduce power consumption; when the image content of a certain display zone is bright, the corresponding backlight module 40 increases the brightness to enhance the display effect.

[0124] Other configurations of the display module in the above embodiments can be derived from various technical solutions known now and in the future to those skilled in the art, and will not be described in detail here.

[0125] In the description of this specification, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0126] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0127] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0128] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0129] It should be noted that although the steps of the method in this application are described in a specific order in the accompanying drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps. The above drawings are merely illustrative of the processes included in the method according to exemplary embodiments of this application and are not intended to be limiting. It is readily understood that the processes shown in the above drawings do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be performed synchronously or asynchronously in multiple modules, for example.

[0130] The foregoing disclosure provides many different implementations or examples for carrying out different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described above. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0131] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A backlight driving method for a display module, characterized in that, The backlight includes multiple backlight modules that correspond one-to-one with multiple display zones of the display panel; the method includes: Obtain the grayscale brightness of the display zone corresponding to each backlight module; Based on the grayscale brightness of each display zone, the frequency of the pulse width modulation signal used to drive each backlight module is determined; wherein, when the grayscale brightness indicates that the display zone is used to display a high grayscale brightness image, the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is a first preset frequency; when the grayscale brightness indicates that the display zone is used to display a low grayscale brightness image, the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is a second preset frequency; the first preset frequency is higher than the second preset frequency; The backlight modules are driven to emit light according to the frequency of the pulse width modulation signal.

2. The backlight driving method for a display module according to claim 1, characterized in that, The first preset frequency is greater than or equal to 10 times the refresh rate of the display panel; and / or the first preset frequency is not less than 1 kHz.

3. The backlight driving method for a display module according to claim 1, characterized in that, The second preset frequency is an integer multiple of the display panel refresh rate and less than 10 times the display panel refresh rate.

4. The backlight driving method for a display module according to claim 1, characterized in that, Based on the grayscale brightness of each of the display zones, the frequency of the pulse width modulation signal used to drive each of the backlight modules is determined, including: The grayscale brightness represented by the grayscale brightness of each display partition is compared with the grayscale brightness threshold. When the grayscale brightness represented by the grayscale brightness of the image is higher than or equal to the grayscale brightness threshold, the display zone is determined to be used to display a high grayscale brightness image, and the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is determined to be a first preset frequency; or, when the grayscale brightness represented by the grayscale brightness of the image is lower than the grayscale brightness threshold, the display zone is determined to be used to display a low grayscale brightness image, and the frequency of the pulse width modulation signal of the backlight module corresponding to the display zone is determined to be a second preset frequency.

5. A method for restarting a backlight control constant current board, characterized in that, The backlight control constant current board includes a step-down module for stepping down the input voltage to the backlight operating voltage, a driving module for driving the backlight, and a control module. The method includes: Obtain the voltage output status of the buck module and the current output status of the drive module; Determine whether an abnormal situation has occurred based on the voltage output status of the step-down module or the current output status of the drive module; In response to an abnormal condition, the input voltage of the step-down module is shut off and a timer is started; In response to the timing duration reaching the preset delay duration, the input voltage of the buck module is switched on to restart the buck module, and the restart count of the buck module is updated; When the number of restarts reaches a preset number, the input voltage of the step-down module is kept off.

6. The restart method for the backlight control constant current board according to claim 5, characterized in that, The preset delay duration is greater than or equal to 1 second and less than or equal to 3 seconds; and / or, the preset number of times is greater than or equal to 2 times and less than or equal to 4 times.

7. The restart method for the backlight control constant current board according to claim 5, characterized in that, Based on the voltage output status of the step-down module, determine whether any abnormal conditions have occurred, including: The output voltage of the buck module is sampled by voltage divider to obtain the status flag bit corresponding to the buck module; When the level represented by the status flag is low, the output of the buck module is determined to be abnormal.

8. The restart method for the backlight control constant current board according to claim 5, characterized in that, Based on the current output status of the drive module, determine whether any abnormal situation has occurred, including: When the output current of the drive module does not meet the preset current range, the output of the drive module is determined to be abnormal.

9. The restart method for the backlight control constant current board according to claim 5, characterized in that, Also includes: The voltage output status of the step-down module and the current output status of the drive module are stored in a register in a preset data format, and the stored data corresponding to the voltage output status and the current output status stored in the register are reported to the control chip of the display module through a serial communication protocol.

10. A backlight control constant current plate, characterized in that, The device includes a step-down module for stepping down the input voltage to the backlight operating voltage, a drive module for driving the backlight, and a control module for performing the method as described in any one of claims 1 to 9.

11. The backlight control constant current plate according to claim 10, characterized in that, Also includes: An input switch circuit is used to provide an input voltage to the input terminal of the step-down module. The input switch circuit is communicatively connected to the control module, wherein the control module is configured to control the input switch circuit to turn on or off the input voltage provided to the step-down module.

12. The backlight control constant current plate according to claim 11, characterized in that, The input switching circuit includes a MOSFET and a transistor. The MOSFET is connected in series between the voltage input terminal and the input terminal of the buck module. The control terminal of the transistor is communicatively connected to the control module. The output terminal of the transistor is connected to the gate of the MOSFET, so that the control module controls the conduction and cutoff of the transistor to realize the switching of the MOSFET.

13. The backlight control constant current plate according to claim 10, characterized in that, It also includes a communication interface for connecting to the control board of the display module. The communication interface is used to receive integrated first and second function signals from the control board. The first function signal is used to control the backlight control constant current board to drive the overall on / off of the backlight source. The second function signal is used to control the backlight control constant current board to drive the overall brightness of the backlight source.

14. A display module, characterized in that, include: The display panel has multiple display zones in its display area; The backlight includes backlight modules that correspond one-to-one with the plurality of display zones; as well as, The backlight control constant current plate as described in any one of claims 10 to 13.

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