Hybrid dimming method and apparatus for led, and computer readable storage medium

Abstract

The present application relates to a hybrid dimming method and apparatus for an LED, and a computer readable storage medium. The hybrid dimming method for an LED comprises the following steps: S1, receiving display grayscale data of a current frame, and determining high-grayscale data and low-grayscale data; S2, when the high-grayscale data is 0, maintaining an LED conduction current at a lowest-gear current, and adjusting a PWM duty cycle by means of the low-grayscale data to adjust the brightness of the LED; and S3, when the high-grayscale data is greater than 0, maintaining the PWM duty cycle at a maximum value 1, determining two adjacent gears of the LED conduction current by means of the high-grayscale data, and adjusting the times for back-and-forth switching of the LED conduction current between the two adjacent gears by means of the low-grayscale data. The hybrid dimming method and apparatus for an LED of the present application can achieve linear grayscale adjustment under hybrid dimming.

Description

LED hybrid dimming method, device and computer-readable storage medium Technical Field

[0001] The present application relates to LED display driving technology, and more specifically, to an LED hybrid dimming method, device, and computer-readable storage medium. Background Art

[0002] Liquid crystal displays (LCDs) hold a significant position in the display market due to their low power consumption, compact size, and lack of radiation. LCDs primarily consist of an LCD panel, a driver circuit, and a backlight module, which provides the backlight for the LCD.

[0003] In recent years, LED backlight modules using them as light sources have attracted considerable attention due to their advantages of higher brightness and lower power consumption. Currently, LED backlight brightness is typically adjusted using PWM (Pulse Width Modulation) dimming. This method maintains a constant current through the LED while varying the PWM duty cycle to control the LED on-time, thereby achieving brightness adjustment. However, PWM dimming has the following drawbacks:

[0004] 1. High refresh rate cannot be achieved when the grayscale value is low; the change of PWM duty cycle may cause LED flickering, resulting in poor display effect.

[0005] 2. When the grayscale value is high, if the PWM frequency is within the human hearing frequency range of 100Hz to 20KHz, the output capacitor will produce howling.

[0006] 3. PWM switching action can easily cause power supply ripple interference.

[0007] To address this issue, hybrid dimming technology has been proposed, which uses a combination of PWM duty cycle and on-current for dimming. In traditional hybrid dimming technology, the input display data is divided into DC (Direct Current) data and PWM data. PWM data is used to control the on-time, while DC data is used to control the on-current. As shown in Figure 1, using 6-bit DC data and 10-bit PWM data as an example, the current calculation formula is:

[0008]

[0009] The current calculation formula is determined by both DC data and PWM data. To obtain the gamma table corresponding to the grayscale level, complex calculations are required, and the calculated gamma is also nonlinear. Therefore, traditional hybrid dimming technology cannot achieve linear grayscale adjustment. Technical issues

[0010] The technical problem to be solved by the present application is to provide an LED hybrid dimming method, device and computer-readable storage medium that can achieve linear grayscale adjustment in response to the above-mentioned defects of the prior art. Technical Solutions

[0011] In order to solve the technical problem, the present application proposes a method for LED hybrid dimming in the first aspect, the method comprising the following steps:

[0012] S1, receiving the grayscale data of the current frame, and determining the high grayscale data and the low grayscale data;

[0013] S2. When the high gray data is 0, the LED conduction current is maintained at the lowest gear current, and the PWM duty cycle is adjusted according to the low gray data to adjust the brightness of the LED;

[0014] S3. When the high gray data is greater than 0, the PWM duty cycle is maintained at a maximum value of 1, two adjacent gears of the LED conduction current are determined by the high gray data, and the time for the LED conduction current to switch back and forth between the two adjacent gears is adjusted by the low gray data.

[0015] In one embodiment of the LED hybrid dimming method according to the first aspect of the present application, step S2 further comprises: dividing the maximum on-state current of the LED into two parts based on a bits of high gray data. a gears, the lowest gear current is:

[0016]

[0017] Among them, I represents the lowest gear current, I max It represents the maximum conduction current of the LED, and a represents the number of bits of high gray data.

[0018] In one embodiment of the LED hybrid dimming method according to the first aspect of the present application, step S2 further includes: adjusting the PWM duty cycle based on b bits of low gray data = low gray data / 2 b , where b represents the number of bits of low-gray data.

[0019] In one embodiment of the LED hybrid dimming method according to the first aspect of the present application, step S3 further includes: determining, through high gray data, that two adjacent gears of the LED conduction current are:

[0020]

[0021]

[0022] Among them, I 高 and I 低Respectively represent the high current and the low current in two adjacent gears of the LED conduction current, I max It represents the maximum conduction current of the LED, and a represents the number of bits of high gray data.

[0023] According to one embodiment of the LED hybrid dimming method described in the first aspect of the present application, in step S3, adjusting the time for the LED conduction current to switch back and forth between the two adjacent gears through the low-gray data further includes: breaking up the low-gray data according to the refresh cycle, outputting a higher current when the low-gray data is present, and outputting a lower current when the low-gray data is not present.

[0024] According to one embodiment of the LED hybrid dimming method described in the first aspect of the present application, in step S3, adjusting the time for the LED conduction current to switch back and forth between the two adjacent gears through the low-gray data further includes: evenly distributing the low-gray data to each refresh cycle, and outputting a higher current at the display clock time corresponding to the low-gray data in each refresh cycle, and outputting a lower current at the rest of the time.

[0025] In order to solve the technical problem, the present application proposes an LED hybrid dimming device in a second aspect, comprising:

[0026] A data acquisition module is used to receive the grayscale data of the current frame and determine the high grayscale data and the low grayscale data;

[0027] A hybrid dimming module is used to maintain the LED conduction current at the lowest gear current when the high gray data is 0, and adjust the PWM duty cycle by adjusting the low gray data to adjust the brightness of the LED. It is also used to maintain the PWM duty cycle at a maximum value of 1 when the high gray data is greater than 0, determine two adjacent gears of the LED conduction current by the high gray data, and adjust the time for the LED conduction current to switch back and forth between the two adjacent gears by the low gray data.

[0028] In order to solve the technical problem, the present application proposes an LED hybrid dimming device in the third aspect, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the LED hybrid dimming method as described above are implemented.

[0029] In order to solve the technical problem, the present application proposes a computer-readable storage medium in a fourth aspect, which stores a computer program. When the computer program is executed by a processor, the steps of the LED hybrid dimming method as described above are implemented. Beneficial effects

[0030] The implementation of the LED hybrid dimming method, device and computer-readable storage medium of the present application has the following beneficial effects: the LED hybrid dimming method and device according to the embodiment of the present application adjusts the LED conduction current gear through high-gray data, and adjusts the PWM duty cycle or conduction current switching time through low-gray data, which not only improves the low-gray display refresh rate and reduces the high current ripple of the power supply during the high-gray display process, but also realizes linear grayscale adjustment under hybrid dimming. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present application will be further described below with reference to the accompanying drawings and embodiments, in which:

[0032] FIG1 is a schematic diagram of a conventional hybrid dimming technology;

[0033] FIG2 is a basic principle diagram of the LED hybrid dimming technology of the present application;

[0034] FIG3 is a flow chart of an LED hybrid dimming method according to an embodiment of the present application;

[0035] FIG4 is a schematic diagram of LED backlight brightness adjustment when 6-bit high gray data, 10-bit low gray data, and the high gray data is 0 in one embodiment of the present application;

[0036] FIG5 is a schematic diagram of LED backlight brightness adjustment when 6-bit high gray data, 10-bit low gray data, and the high gray data is greater than 0 in one embodiment of the present application;

[0037] FIG6 is a logic block diagram of an LED hybrid dimming device according to an embodiment of the present application;

[0038] FIG7 is a logic block diagram of an LED hybrid dimming device according to another embodiment of the present application. Modes for Carrying Out the Invention

[0039] To make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely intended to explain this application and are not intended to limit this application. Furthermore, the embodiments and features of the embodiments in this application may be combined with each other unless there is a conflict.

[0040] This application proposes an LED hybrid dimming technology that performs hybrid dimming by adjusting the PWM duty cycle and the conduction current. The basic principle is shown in FIG2 , where the current gain data is used to adjust the LED maximum conduction current I max , high gray data is used to adjust the LED conduction current gear, and low gray data is used to adjust the PWM duty cycle or conduction current switching time.

[0041] Based on the above basic principles, the present application proposes a LED hybrid dimming method. FIG3 shows a flow chart of an LED hybrid dimming method 10 according to an embodiment of the present application. As shown in FIG3 , the LED hybrid dimming method 10 includes the following steps:

[0042] In step S11 , the current frame display grayscale data G is received, and high grayscale data and low grayscale data are determined.

[0043] In step S12, when the high gray data is 0, the LED conduction current is kept at the lowest gear current, and the PWM duty cycle is adjusted by the low gray data to adjust the LED brightness. In a specific embodiment, the LED hybrid dimming method 10 divides the LED maximum conduction current into 2 based on the a-bit high gray data. a gears, the lowest gear current is:

[0044]

[0045] Among them, I represents the lowest gear current, I max Indicates the maximum on-state current of the LED, a indicates the number of bits of high gray data. If the low gray data is b bits, then the PWM duty cycle adjusted based on b bits of low gray data = low gray data / 2 b , where b represents the number of bits of low-gray data.

[0046] In step S13, when the high gray data is greater than 0, the PWM duty cycle is maintained at a maximum value of 1, two adjacent gears of the LED conduction current are determined based on the high gray data, and the time for the LED conduction current to switch back and forth between the two adjacent gears is adjusted based on the low gray data. In a specific embodiment, the LED hybrid dimming method 10 determines two adjacent gears of the LED conduction current based on the high gray data as follows:

[0047]

[0048]

[0049] Among them, I 高 and I 低 Respectively represent the high current and low current in the two adjacent gears of the LED conduction current, I maxrepresents the maximum LED on-state current, and a represents the number of bits of high-gray data. The specific switching method used in step S13 to adjust the switching time between the two adjacent levels of the LED on-state current using low-gray data is to break up the low-gray data according to the refresh cycle, outputting a higher current level when low-gray data is present, and outputting a lower current level when low-gray data is not present. For example, the low-gray data can be evenly distributed throughout each refresh cycle, with the high current level output during the display clock time corresponding to low-gray data in each refresh cycle, and the lower current level output during the remaining time.

[0050] The following uses 6-bit high-grayscale data and 10-bit low-grayscale data as examples to illustrate how the LED hybrid dimming method 10 of the above embodiment of the present application adjusts the brightness of the LED backlight. The high-grayscale data is 6 bits, which means that the maximum LED on-current is divided into 64 levels; the low-grayscale data is 10 bits, which means that the PWM is divided into 1024 levels.

[0051] As shown in Figure 4, if the high gray data is 0, the LED conduction current is maintained at the lowest gear current, that is: I = 1 / 64 * I max , adjust the PWM duty cycle through the low gray data, so the average current flowing through the LED in the current frame is: I arg = low gray data / 1024*I.

[0052] As shown in Figure 5, if the high gray data is greater than 0, the PWM duty cycle is maintained at a maximum value of 1. The two adjacent gears of the LED conduction current are determined by the high gray data as follows:

[0053]

[0054] The conduction current is adjusted by low gray data to switch back and forth between the two gears, so the average current flowing through the LED in the current frame is:

[0055] I arg = (low gray data / 1024 *I 高 ) + ((1024 - low gray data) / 1024 *I 低 )

[0056] As mentioned above, the conduction current gear switching method can be adopted by breaking up the low gray data according to the refresh cycle, outputting the high current when the low gray data is present, and outputting the low current when the low gray data is not present. In other words, the low gray data controls the duty cycle of the high current duration (the rest of the time is the low current). In order to ensure the display effect, the high current duration can be evenly distributed to each refresh cycle. For example, when the high gray data is 4 and the low gray data is 32, that is, the display data is (4*1024+32)=4128, the high current is (4+1) / 64*I max , the lower current is 4 / 64*Imax At this time, the high current time is controlled by the low gray data. If the refresh cycle is 16 and each cycle has 64 display clocks, then each cycle has 32 / 16=2 display clocks for the high current, and the remaining time (64-2)=62 display clocks for the low current.

[0057] The above LED hybrid dimming technology can achieve linear grayscale adjustment. Assuming the display grayscale data is G, Data_dc is the upper 6 bits, and Data_pwm is the lower 10 bits, the calculation is as follows:

[0058] (1) If Data_dc=0, then Data_pwm is the PWM duty cycle data, and the current I dc =I max / 64, the average current is:

[0059] I arg =I dc *Data_pwm / 1024 =I max / 64 *Data_pwm / 1024 =I max *Data_pwm / 65536

[0060] Since Data_dc=0 and Data_pwm is the lower 10 bits of G, then G=Data_pwm. Therefore, the calculated formula satisfies the theoretical current value:

[0061] I arg =I max *G / 65536

[0062] (2) If Data_dc>0, then Data_pwm is the duty cycle of the time when the DC current gear is Data_dc, and the current gear is Data_dc-1 for the rest of the time. The average current is:

[0063]

[0064]

[0065] Since Data_dc is the upper 6 bits of G and Data_pwm is the lower 10 bits of G, then G=Data_pwm+Data_dc*1024. Therefore, the theoretical current formula is satisfied:

[0066] I arg =I max *G / 65536

[0067] The comparison between the average current and the theoretical current of the LED hybrid dimming method according to the above embodiment of the present application is as follows:

[0068] Such as I max Set to 64mA, display grayscale data G is 512, then the high gray data is 0, the low gray data is 512, then the average current is:

[0069] I arg = low gray data / 1024 *I= 512 / 1024 * 1 / 64 * 64mA= 0.5mA

[0070] The theoretical current is:

[0071] I arg =I max *G / 65536 = 64 * 512 / 65536= 0.5mA

[0072] If the displayed grayscale data G is 4096, the high gray data is 4 and the low gray data is 0, then the average current is:

[0073]

[0074] The theoretical current is:

[0075] I arg =I max *G / 65536 = 64 * 4096 / 65536= 4mA

[0076] If the displayed grayscale data G is 4608, the high gray data is 4, and the low gray data is 512, then the average current is:

[0077] I arg = (low gray data / 1024 *I 高 ) + ((1024 - low gray data) / 1024 *I 低 )

[0078] = (512 / 1024*(4+1) / 64*64mA) + ((1024-512) / 1024*4 / 64*64mA)

[0079] = 4.5mA

[0080] The theoretical current is:

[0081] I arg =I max *G / 65536 = 64 * 4608 / 65536= 4.5mA

[0082] In summary, the theoretical current is consistent with the actual current calculation results, indicating that the theoretical current I arg =Imax *G / 65536 is correct. This method can be used to achieve linear grayscale adjustment under hybrid dimming.

[0083] Based on the above LED hybrid dimming method, the present application also proposes an LED hybrid dimming device. Figure 6 shows a logic block diagram of an LED hybrid dimming device 20 according to an embodiment of the present application. As shown in Figure 6, the LED hybrid dimming device 20 includes a data acquisition module 21 and a hybrid dimming module 22. Among them, the data acquisition module 21 is used to receive the grayscale data displayed in the current frame and determine the high gray data and the low gray data. The hybrid dimming module 22 is used to keep the LED conduction current at the lowest gear current when the high gray data is 0, and adjust the PWM duty cycle by adjusting the low gray data to adjust the brightness of the LED. The hybrid dimming module 22 is also used to keep the PWM duty cycle at a maximum value of 1 when the high gray data is greater than 0, determine the two adjacent gears of the LED conduction current by the high gray data, and adjust the time for the LED conduction current to switch back and forth between the two adjacent gears by the low gray data.

[0084] For further specific implementation of each module of the LED hybrid dimming device 20 , reference may be made to the detailed description of each step of the aforementioned LED hybrid dimming method 10 .

[0085] Figure 7 shows a logical structure diagram of an LED hybrid dimming device 30 according to another exemplary embodiment of the present application. As shown in Figure 7 , the LED hybrid dimming device 30 includes a processor 31 and a memory 32, which are communicatively connected to each other. Memory 32 stores a computer program that, when executed by processor 31, causes processor 31 to implement the steps of the LED hybrid dimming method 10 described in the aforementioned exemplary embodiment of the present application.

[0086] The present application further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the LED hybrid dimming method 10 of the aforementioned embodiment of the present application.

[0087] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A LED hybrid dimming method, characterized in that: The method comprises the following steps: S1, receiving the grayscale data of the current frame, and determining the high gray data and the low gray data; S2, when the high gray data is 0, the LED conduction current is maintained at the lowest gear current, and the PWM duty cycle is adjusted by the low gray data to adjust the brightness of the LED; S3. When the high gray data is greater than 0, the PWM duty cycle is maintained at a maximum value of 1, two adjacent gears of the LED on-current are determined by the high gray data, and the time for the LED on-current to switch back and forth between the two adjacent gears is adjusted by the low gray data.

2. [Corrected 11.06.2024 according to Rule 91] The LED hybrid dimming method according to claim 1, characterized in that: Step S2 further includes: dividing the maximum conduction current of the LED into two a gears, the lowest gear current is: Among them, I represents the lowest gear current, I max It represents the maximum conduction current of LED, and a represents the number of bits of high gray data.

3. The LED hybrid dimming method according to claim 2, characterized in that: Step S2 further includes: adjusting the PWM duty cycle based on b bits of low-gray data = low-gray data / 2 b , where b represents the number of bits of low-gray data.

4. [Corrected 11.06.2024 according to Rule 91] The LED hybrid dimming method according to claim 1, characterized in that: Step S3 further includes: determining two adjacent gears of the LED conduction current through high gray data as follows: Among them, I 高 and I 低 They represent the high current and the low current in two adjacent gears of the LED conduction current, I max It represents the maximum conduction current of LED, and a represents the number of bits of high gray data.

5. The LED hybrid dimming method according to claim 4, characterized in that: In step S3, adjusting the switching time of the LED conduction current between the two adjacent gears by the low gray data further includes: breaking up the low gray data according to the refresh cycle, outputting a higher current when the low gray data is present, and outputting a lower current when the low gray data is not present.

6. The LED hybrid dimming method according to claim 5, characterized in that: In step S3, adjusting the time for the LED conduction current to switch back and forth between the two adjacent gears by the low-gray data further includes: evenly distributing the low-gray data to each refresh cycle, outputting a higher current at the display clock time corresponding to the low-gray data in each refresh cycle, and outputting a lower current at the rest of the time.

7. An LED hybrid dimming device, characterized in that: include: A data acquisition module is used to receive grayscale data displayed in the current frame and determine high grayscale data and low grayscale data; A hybrid dimming module is used to keep the LED conduction current at the lowest gear current when the high gray data is 0, and adjust the brightness of the LED by adjusting the PWM duty cycle through the low gray data; it is also used to keep the PWM duty cycle at a maximum value of 1 when the high gray data is greater than 0, determine two adjacent gears of the LED conduction current through the high gray data, and adjust the time for the LED conduction current to switch back and forth between the two adjacent gears through the low gray data.

8. An LED hybrid dimming device, characterized in that: The method comprises a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the LED hybrid dimming method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the steps of the LED hybrid dimming method according to any one of claims 1 to 6 are implemented.

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