A method for adjusting power supply output voltage, dimming controller and backlight system

Abstract

The present invention discloses a method for adjusting the output voltage of a power supply, a dimming controller and a backlight system. The dimming controller first determines the current full-screen brightness cumulative value and the current brightness characteristic data according to the backlight brightness data of the current frame image, and then searches for a first target PWM value corresponding to the current full-screen brightness cumulative value and the current brightness characteristic data from a preset corresponding relationship. The switching power supply outputs the power supply voltage based on the first target PWM value, wherein the preset corresponding relationship is the corresponding relationship between the historical full-screen brightness cumulative value, the historical brightness characteristic data and the historical PWM value, and the historical brightness characteristic data is obtained based on the backlight brightness data of the historical image. Since the output power supply voltage is based on the PWM value found from the preset corresponding relationship, compared with repeatedly adjusting the power supply output voltage according to the display brightness of multiple frames of images, the current picture and the backlight picture can be synchronized to improve the display effect.

Description

Technical Field

[0001] The invention relates to the technical field of LED driving, and in particular to a method for adjusting a power supply output voltage, a dimming controller and a backlight system. Background Art

[0002] For the LCD backlight panel, since the brightness value and the lit area of ​​each frame of the image may be different, the power of the LCD backlight panel will change. For example, when the image changes from a plurality of lit pixel partitions to a few lit pixel partitions, or the overall brightness of the image decreases, the power consumption transmitted by the power supply line will also decrease, that is, the voltage difference in the power supply line will decrease, and the LED supply voltage VLED will decrease. At this time, the power supply output voltage will be lowered. After adjusting the power supply output voltage, the brightness requirement of the LCD display panel can be met.

[0003] The method for adjusting the power supply output voltage provided in the prior art needs to repeatedly adjust the power supply output voltage according to the display brightness of multiple frames of images to achieve the expected output voltage. When the power supply output voltage reaches the expected output voltage, the currently displayed image has long expired, resulting in the current image and the backlight image being out of sync, affecting the display effect. Summary of the invention

[0004] The present invention provides a method for adjusting power output voltage, a dimming controller and a backlight system, which are used to solve the problem in the prior art that when the power output voltage is adjusted according to the display image, the current image and the backlight image are out of sync, thereby affecting the display effect.

[0005] In a first aspect, the present application discloses a method for adjusting a power supply output voltage, which is applied to a liquid crystal backlight panel. The method comprises:

[0006] The dimming controller determines the current full-screen brightness accumulation value and the current brightness characteristic data according to the backlight brightness data of the current frame image;

[0007] The dimming controller searches for a first target PWM value corresponding to the current full-screen brightness accumulation value and the current brightness characteristic data from a preset corresponding relationship, wherein the preset corresponding relationship is a corresponding relationship between a historical full-screen brightness accumulation value, a historical brightness characteristic data, and a historical PWM value, and the historical brightness characteristic data is obtained based on backlight brightness data of a historical image;

[0008] The dimming controller sends the first target PWM value to a switching power supply, and the switching power supply outputs a power supply voltage for powering an LED in a liquid crystal backlight panel based on the first target PWM value.

[0009] In a possible implementation, the dimming controller determines current brightness characteristic data according to backlight brightness data of a current frame image, including:

[0010] The dimming controller determines a current brightness histogram according to the backlight brightness data;

[0011] The dimming controller extracts features from the current brightness histogram to obtain the current brightness feature data;

[0012] The dimming controller searches for a first target PWM value corresponding to the current full-screen brightness accumulation value and the current brightness characteristic data from a preset corresponding relationship, including:

[0013] The dimming controller searches the preset corresponding relationship for a historical full-screen brightness accumulated value that is the same as the current full-screen brightness accumulated value;

[0014] The dimming controller compares the historical brightness feature data corresponding to the historical full-screen brightness cumulative value found with the current brightness feature data for similarity, and determines the target historical brightness feature data according to the comparison result;

[0015] The dimming controller uses the historical PWM value corresponding to the target historical brightness characteristic data in the preset corresponding relationship as the first target PWM value.

[0016] In a possible implementation, the dimming controller compares the historical brightness feature data corresponding to the historical full-screen brightness accumulation value found with the current brightness feature data for similarity, and determines the target historical brightness feature data according to the comparison result, including:

[0017] The dimming controller uses a gradient contrast method to calculate a first similarity between the first data and the fourth data, uses an absolute value of a difference to calculate a second similarity between the second data and the fifth data, and uses an absolute value of a difference to calculate a third similarity between the third data and the sixth data;

[0018] The dimming controller calculates the sum of the first similarity, the second similarity and the third similarity for each historical brightness feature data found, and uses the historical brightness feature data corresponding to the maximum sum value among the historical brightness feature data as the target historical brightness feature data;

[0019] Among them, the historical brightness feature data includes first data representing histogram equalization, second data representing the accumulated value of each row of brightness data, and third data representing the accumulated value of each column of brightness, and the current brightness feature data includes fourth data representing histogram equalization, fifth data representing the accumulated value of each row of brightness data, and sixth data representing the accumulated value of each column of brightness.

[0020] In a possible implementation, the preset corresponding relationship is obtained by:

[0021] The dimming controller determines a historical brightness histogram and a historical full-screen brightness accumulation value according to the backlight brightness data of the historical frame image;

[0022] The dimming controller extracts features from the historical brightness histogram to obtain historical brightness feature data;

[0023] The dimming controller uses the historical full-screen brightness accumulation value, the historical brightness characteristic data, and the PWM value corresponding to the historical frame image as the preset corresponding relationship.

[0024] In a possible implementation, the method further includes:

[0025] If the first target PWM value is not found from the preset corresponding relationship, the dimming controller adopts PI regulation according to the output voltage of the driving port of each dimmer to obtain a second target PWM value;

[0026] The dimming controller sends the second target PWM value to the switching power supply, and the switching power supply outputs a power supply voltage based on the second target PWM value.

[0027] In a possible implementation manner, after the dimming controller obtains the second target PWM value, the method further includes:

[0028] The dimming controller searches the preset corresponding relationship for a historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value of the current frame image;

[0029] If it is determined that it does not exist, the dimming controller updates the preset corresponding relationship based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

[0030] In a possible implementation, the method further includes:

[0031] The dimming controller determines to maintain the current PWM value according to the output voltage of the output port of each dimmer;

[0032] The dimming controller searches the preset corresponding relationship for a historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value of the current frame image;

[0033] If it is determined that it does not exist, the dimming controller updates the preset corresponding relationship based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the currently output PWM value.

[0034] In a second aspect, the present application further provides a dimming controller applied to a liquid crystal backlight panel, comprising:

[0035] A determination module, used to determine the current full-screen brightness accumulation value and current brightness feature data according to the backlight brightness data of the current frame image;

[0036] A search module, used to search for a first target PWM value corresponding to the current full-screen brightness accumulated value and the current brightness characteristic data from a preset corresponding relationship, wherein the preset corresponding relationship is a corresponding relationship between a historical full-screen brightness accumulated value, a historical brightness characteristic data, and a historical PWM value, and the historical brightness characteristic data is obtained based on backlight brightness data of historical images;

[0037] The sending module is used to send the first target PWM value to the switching power supply, and the switching power supply outputs a power supply voltage for powering the LED in the liquid crystal backlight panel based on the first target PWM value.

[0038] In a possible implementation manner, the determining module is specifically configured to:

[0039] Determine a current brightness histogram according to the backlight brightness data;

[0040] Performing feature extraction on the current brightness histogram to obtain the current brightness feature data;

[0041] The search module is specifically used for:

[0042] Searching for a historical full-screen brightness accumulated value that is the same as the current full-screen brightness accumulated value from the preset corresponding relationship;

[0043] The historical brightness feature data corresponding to the historical full-screen brightness cumulative value found are compared with the current brightness feature data for similarity, and the target historical brightness feature data is determined according to the comparison result;

[0044] The historical PWM value corresponding to the target historical brightness characteristic data in the preset corresponding relationship is used as the first target PWM value.

[0045] In a possible implementation, the search module is specifically used to:

[0046] Calculating a first similarity between the first data and the fourth data using a gradient contrast method, calculating a second similarity between the second data and the fifth data using an absolute value of a difference, and calculating a third similarity between the third data and the sixth data using an absolute value of a difference;

[0047] For each historical brightness feature data found, respectively calculate the sum of the first similarity, the second similarity and the third similarity, and use the historical brightness feature data corresponding to the maximum sum value among the historical brightness feature data as the target historical brightness feature data;

[0048] Among them, the historical brightness feature data includes first data representing histogram equalization, second data representing the accumulated value of each row of brightness data, and third data representing the accumulated value of each column of brightness, and the current brightness feature data includes fourth data representing histogram equalization, fifth data representing the accumulated value of each row of brightness data, and sixth data representing the accumulated value of each column of brightness.

[0049] In a possible implementation, the preset corresponding relationship is obtained by:

[0050] According to the backlight brightness data of the historical frame image, determine the historical brightness histogram and the historical full-screen brightness accumulation value;

[0051] Performing feature extraction on the historical brightness histogram to obtain historical brightness feature data;

[0052] The historical full-screen brightness accumulated value, the historical brightness characteristic data and the PWM value corresponding to the historical frame image are used as the preset corresponding relationship.

[0053] In a possible implementation, the search module is specifically used to:

[0054] If the first target PWM value is not found from the preset corresponding relationship, a second target PWM value is obtained by adopting PI regulation according to the output voltage of the driving port of each dimmer;

[0055] The sending module is also used for:

[0056] The second target PWM value is sent to the switching power supply, and the switching power supply outputs a power supply voltage based on the second target PWM value.

[0057] In a possible implementation, after obtaining the second target PWM value, the search module is further configured to:

[0058] Searching for a historical full-screen brightness accumulation value that is the same as a current full-screen brightness accumulation value of a current frame image from the preset corresponding relationship;

[0059] If it is determined that it does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

[0060] In a possible implementation manner, the determining module is further configured to:

[0061] According to the output voltage of the output port of each dimmer, determine to maintain the current PWM value;

[0062] The search module is also used to:

[0063] Searching for a historical full-screen brightness accumulation value that is the same as a current full-screen brightness accumulation value of a current frame image from the preset corresponding relationship;

[0064] If it is determined that it does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the current output PWM value.

[0065] In a third aspect, an embodiment of the present application further provides a backlight system, comprising a liquid crystal backlight panel, a switching power supply, and a dimming controller as described in any one of the second aspects, wherein the liquid crystal backlight panel comprises a dimmer and an LED;

[0066] The dimming controller, the switching power supply, the LED and the dimmer are connected in sequence, and the dimming controller is also electrically connected to the dimmer.

[0067] The beneficial effects of the present invention are as follows:

[0068] The present invention provides a method for adjusting the output voltage of a power supply, a dimming controller and a backlight system. The dimming controller first determines the current full-screen brightness accumulation value and the current brightness characteristic data according to the backlight brightness data of the current frame image, and then searches for a first target PWM value corresponding to the current full-screen brightness accumulation value and the current brightness characteristic data from a preset corresponding relationship. The switching power supply outputs the power supply voltage based on the first target PWM value. Since the output power supply voltage is based on the PWM value found from the preset corresponding relationship, compared with repeatedly adjusting the power supply output voltage according to the display brightness of multiple frames of images, the current picture and the backlight picture can be synchronized, thereby improving the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0070] Figure 1 A schematic structural diagram of a backlight system provided by an embodiment of the present invention;

[0071] Figure 2 A schematic flow chart of a method for adjusting the output voltage of a power supply provided by an embodiment of the present invention;

[0072] Figure 3 A schematic diagram of a process for adjusting the output voltage of a power supply provided by an embodiment of the present invention;

[0073] Figure 4 A schematic structural diagram of a backlight controller provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0075] like Figure 1 The figure shows the structure diagram of the backlight system. Figure 1 In the embodiment, the backlight system includes a dimming controller 11, a liquid crystal backlight panel 12 and a switching power supply 13, wherein the liquid crystal backlight panel 12 includes a dimmer 12 and an LED.

[0076] The dimming controller 11 inputs dimming data to the DI port of the dimmer 121. The dimmer 121 drives the LED through the driving ports (OUT0, OUT1, OUT2 and OUT3) based on the received dimming data. In addition, the switching power supply 13 provides the LED with a power supply voltage VLED. The power supply voltage VLED falls on the driving port of the dimmer 12 after passing through the voltage drop of the LED.

[0077] When the display brightness of the display screen changes, the power output voltage of the switching power supply 13 is adjusted to meet the brightness requirements of the liquid crystal display panel. In the related art, when the power output voltage is adjusted, there is a problem that the current screen and the backlight screen are out of sync, which affects the display effect.

[0078] Based on the above technical problems, the embodiments of the present application provide a method for adjusting the output voltage of a power supply, a dimming controller and a backlight system. The dimming controller first determines the current full-screen brightness accumulation value and the current brightness characteristic data according to the backlight brightness data of the current frame image, and then searches for the first target PWM value corresponding to the current full-screen brightness accumulation value and the current brightness characteristic data from the preset corresponding relationship. The switching power supply outputs the power supply voltage based on the first target PWM value. Since the output power supply voltage is based on the PWM value found from the preset corresponding relationship, compared with repeatedly adjusting the power supply output voltage according to the display brightness of multiple frames of images, the current picture and the backlight picture can be synchronized to improve the display effect.

[0079] The method for adjusting the output voltage of a power supply, the dimming controller and the backlight system provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0080] like Figure 2 As shown, a method for adjusting the output voltage of a power supply provided in an embodiment of the present application specifically includes the following steps:

[0081] S201, the dimming controller determines the current full-screen brightness accumulation value and the current brightness characteristic data according to the backlight brightness data of the current frame image;

[0082] S202, the dimming controller searches for a first target PWM value corresponding to the current full-screen brightness accumulated value and the current brightness characteristic data from a preset corresponding relationship, wherein the preset corresponding relationship is a corresponding relationship between a historical full-screen brightness accumulated value, historical characteristic data, and a historical PWM value, and the historical characteristic data is obtained based on the backlight brightness data of the historical picture;

[0083] S203: The dimming controller sends the first target PWM value to a switching power supply, and the switching power supply outputs a power supply voltage for powering LEDs in a liquid crystal backlight panel based on the first target PWM value.

[0084] The method for adjusting the power supply output voltage provided in the embodiment of the present application is applied to a liquid crystal backlight panel. By determining a first target PWM value, the power supply voltage input to the power supply end of the LED in the liquid crystal backlight panel is adjusted. Since the first target PWM value is determined from a preset corresponding relationship, compared to repeatedly adjusting the power supply output voltage according to the display brightness of multiple frames of images, the current image and the backlight image can be synchronized, thereby improving the display effect.

[0085] The preset correspondence in the embodiment of the present application can be obtained based on multiple frames of historical images. Specifically, for each frame of historical image, the dimming controller determines the historical brightness histogram and the historical full-screen brightness accumulation value based on the dimming data of the frame of historical image, and then performs feature extraction on the historical brightness histogram to obtain historical brightness feature data. Finally, the historical full-screen brightness accumulation value, the historical brightness feature data and the historical PWM value are used as the preset correspondence.

[0086] The historical brightness feature data may include first data representing histogram equalization, second data representing the accumulated value of each row of brightness data, and third data representing the accumulated value of each column of brightness.

[0087] It should be noted that, in addition to the above three types of data, the historical brightness feature data may also include other feature data of the histogram, and the embodiment of the present application does not impose any limitation on this.

[0088] The specific method of extracting features from the historical brightness histogram to obtain historical brightness feature data can refer to the method of extracting features from the histogram in the relevant technology, which will not be repeated here.

[0089] It should also be noted that the historical PWM value in the embodiment of the present application is the adjusted PWM value corresponding to the frame of historical image, that is, the power supply voltage output by the switching power supply based on the PWM value meets the brightness requirement of the backlight of the frame of historical image.

[0090] In a specific implementation, the preset corresponding relationship can be displayed in the form of a table, as shown in Table 1 below:

[0091] Historical full screen brightness accumulation value First Data Second data Third data Historical PWM values A1 a1 b1 c1 d1％ A1 a2 b2 c2 d2％ A1 a3 b3 c3 d3％ A2 a4 b4 c4 d4％ A2 a5 b5 c5 d5％ A3 a6 b6 c6 d6％ A3 a7 b7 c7 d7％ A3 a8 b8 c8 d8％

[0092] Table 1

[0093] The above preset correspondence may be stored in the dimming controller. When the dimming controller receives the backlight brightness data of the current frame image, it directly searches for the first target PWM value corresponding to the current full-screen brightness accumulated value and the current brightness characteristic data from the preset correspondence stored in the dimming controller.

[0094] Specifically, from the preset corresponding relationship, the current brightness feature data is determined according to the backlight brightness data of the current frame image. First, the dimming controller determines the current brightness histogram according to the backlight brightness data of the current frame image, and then performs feature extraction on the current brightness histogram to obtain the current brightness feature data.

[0095] When the dimming controller searches for the first target PWM value corresponding to the current full-screen brightness accumulated value and the current brightness characteristic data from the preset correspondence, it first searches for the historical full-screen brightness accumulated value that is the same as the current full-screen brightness accumulated value from the preset correspondence, compares the historical brightness characteristic data corresponding to the searched historical full-screen brightness accumulated value with the current brightness characteristic data for similarity, determines the target historical brightness characteristic data based on the comparison result, and finally uses the historical PWM value corresponding to the target historical brightness characteristic data in the preset correspondence as the first target PWM value.

[0096] In an embodiment of the present application, by performing feature extraction on the brightness histogram to obtain brightness feature data, and then determining the first target PWM value from the historical PWM values ​​in the preset corresponding relationship based on the current brightness feature data and the historical brightness feature data in the preset corresponding relationship, the determined PWM value can be made more accurate.

[0097] In one embodiment, when determining the target historical brightness feature data based on the comparison results, the gradient contrast method can be used to calculate the first similarity between the first data and the fourth data, the absolute value of the difference can be used to calculate the second similarity between the second data and the fifth data, and the absolute value of the difference can be used to calculate the third similarity between the third data and the sixth data. For each historical brightness feature data found, the sum of the first similarity, the second similarity and the third similarity is calculated respectively, and the historical brightness feature data corresponding to the largest sum is used as the target historical brightness feature data.

[0098] For example, according to the brightness data of the current frame image, the current full-screen brightness cumulative value is determined to be A1 and the current brightness histogram, and the current brightness histogram is feature extracted to obtain the current brightness feature data (fourth data a44, fifth data b55 and sixth data c66). The dimming controller searches for the same historical full-screen brightness cumulative value as A1 from Table 1, and finds 3 historical full-screen brightness cumulative values ​​A1. Then, the historical brightness feature data (first data, second data and third data) corresponding to each historical full-screen brightness cumulative value A1 are compared with the current brightness feature data (fourth data a44, fifth data b55 and sixth data c66) for similarity. The specific comparison process is:

[0099] Calculate the similarity B1 between the first data a1 and the fourth data a44 using a gradient contrast method;

[0100] The similarity B2 between the second data b1 and the fifth data b55 is calculated by using the absolute value of the difference;

[0101] The similarity B3 between the third data c1 and the sixth data c66 is calculated by using the absolute value of the difference;

[0102] Calculate B1+B2+B3=C1.

[0103] Calculate the similarity B4 between the first data a2 and the fourth data a44 using a gradient contrast method;

[0104] The similarity B5 between the second data b2 and the fifth data b55 is calculated by using the absolute value of the difference;

[0105] The similarity B6 between the third data c2 and the sixth data c66 is calculated by using the absolute value of the difference;

[0106] Calculate B4+B5+B6=C2.

[0107] Calculate the similarity B7 between the first data a3 and the fourth data a44 using a gradient contrast method;

[0108] The similarity B8 between the second data b3 and the fifth data b55 is calculated by using the absolute value of the difference;

[0109] The similarity B9 between the third data c3 and the sixth data c66 is calculated by using the absolute value of the difference;

[0110] Calculate B7+B8+B9=C3.

[0111] Compare C1, C2 and C3. If C1 is the largest, the first data a1, the second data b1 and the third data b3 corresponding to C1 are used as the target historical brightness feature data.

[0112] The historical PWM value d1% corresponding to the target historical brightness characteristic data is used as the first target PWM value.

[0113] In one embodiment, if the first target PWM value is not found in the preset correspondence, for example, the dimming controller determines that the current full-screen brightness accumulation value is A4 based on the backlight brightness data of the current frame image, and there is no historical full-screen brightness accumulation value with a value of A4 in the table shown in Table 1. Therefore, the dimming controller does not find the first target PWM value in the preset correspondence. At this time, the dimming controller adopts PI adjustment according to the output voltage of the driving port of the dimmer to obtain the second target PWM value.

[0114] Specifically, the dimming controller obtains the output voltage of each driving port of the dimmer, and if there are multiple dimmers, the output voltage of each driving port of each dimmer is obtained.

[0115] After the dimming controller obtains the output voltage of each driving port in each dimmer, it compares the obtained output voltage with the preset voltage, and determines whether the output voltage is undervoltage or overvoltage based on the comparison result. Specifically, the preset voltage may include a first preset voltage and a second preset voltage, wherein the first preset voltage is less than the second preset voltage. When the output voltage is less than the first preset voltage, it is determined that the output voltage is undervoltage; when the output voltage is greater than the second preset voltage, it is determined that the output voltage is overvoltage; when the output voltage is between the first preset voltage and the second preset voltage, it is determined that the output voltage is neither undervoltage nor overvoltage, that is, the output voltage is within a normal range.

[0116] After comparing each output voltage, the dimming controller determines the number of output voltage undervoltages and the number of output voltage overvoltages. For example, there are 3 dimmers, each dimmer has 4 drive ports, then the dimming controller obtains 12 output voltages, compares each output voltage with the first preset voltage and the second preset voltage, and determines the number of overvoltages and undervoltages based on the 12 comparison results.

[0117] In one embodiment, after the dimming controller determines the undervoltage number and the overvoltage number, the dimming controller compares the undervoltage number with a first preset threshold value, and if the undervoltage number is greater than the first preset threshold value, the dimming controller calculates a first product of the undervoltage number and a preset proportional control coefficient, and calculates a second product of the undervoltage number and a preset integral control coefficient, and uses the sum of the first product, the second product and the accumulated value as the second target PWM value;

[0118] If it is determined that the undervoltage quantity is less than or equal to the first preset threshold value, and the overvoltage quantity is greater than the second preset threshold value, the dimming controller calculates a third product of the overvoltage quantity and the proportional control coefficient, and calculates a fourth product of the overvoltage quantity and the integral control coefficient, and uses the sum of the third product, the fourth product and the accumulated value as the second target PWM value;

[0119] The accumulated value is the sum of all second products and / or fourth products when calculating the second target PWM value corresponding to the image before the current frame image.

[0120] For example, the first preset threshold is 6 and the second preset threshold is 5. If the number of undervoltages is 7, that is, the undervoltage number 7 is greater than the first preset threshold 6, then the PWM value = Kp*7+Ki*7+Ki*(e1+e2+…); if the number of undervoltages is 4 and the number of overvoltages is 6, that is, the undervoltage number 4 is less than the first preset threshold 6, and the overvoltage number 6 is greater than the second preset threshold 5, then the PWM value = Kp*6+Ki*6+Ki*(e1+e2+…); wherein Kp is the proportional control coefficient, Ki is the integral control coefficient, and Ki*(e1+e2+…) is the accumulated value.

[0121] For another example, the first preset threshold is 6, the second preset threshold is 5, the current frame image is the first frame image, and the undervoltage number determined by the dimming controller is 7, then the PWM value = Kp*7+Ki*7; in the second frame image, the undervoltage number determined by the dimming controller is 8, then the PWM value = Kp*8+Ki*8+Ki*7; in the third frame image, the undervoltage number determined by the dimming controller is 5, and the overvoltage number is 6, then the PWM value = Kp*(-6)+Ki*(-6)+Ki*(7+8)…

[0122] It should be noted that if the number of undervoltages is greater than the first preset threshold, it is determined that the current output voltage needs to be increased; if the number of undervoltages is less than or equal to the first preset threshold and the number of overvoltages is greater than the second preset threshold, it is determined that the current output voltage needs to be reduced.

[0123] In a specific implementation, both the first preset threshold and the second preset threshold may be 0.

[0124] In a specific implementation, if the number of undervoltages is less than or equal to a first preset threshold, and the number of overvoltages is less than or equal to a second preset threshold, that is, other situations except the above two situations, it means that the current PWM value can meet the brightness requirement of the backlight of the current frame image, that is, it is determined to maintain the current PWM value, then the dimming controller determines the current full-screen brightness cumulative value based on the backlight brightness data of the current frame image, and then searches for the historical full-screen brightness cumulative value that is the same as the current full-screen brightness cumulative value of the current frame image from the preset correspondence. If it is determined that it does not exist, the dimming controller determines the brightness histogram based on the backlight brightness data of the current frame image, and then performs feature extraction on the brightness histogram to obtain current brightness feature data. Finally, based on the current full-screen brightness cumulative value, the current brightness feature data corresponding to the current frame image, and the currently output PWM value, the preset correspondence is updated.

[0125] For example, when the number of undervoltages is less than or equal to the first preset threshold value, and the number of overvoltages is less than or equal to the second preset threshold value, the dimming controller determines the current full-screen brightness cumulative value as A4 based on the backlight brightness data of the current frame image, and searches Table 1 for whether A4 exists in the historical full-screen brightness cumulative value. If it does not exist, the dimming controller determines the brightness histogram based on the backlight brightness data of the current frame image, and then performs feature extraction on the brightness histogram to obtain data a9 representing histogram equalization, data b9 representing the cumulative value of each row of brightness data, and data c9 representing the cumulative value of each column of brightness in the current brightness feature data, and determines that the current output PWM value is d9%. Based on A4, a9, b9, c9 and d9%, Table 1 is updated to obtain Table 2, as shown in the following table:

[0126] Historical full screen brightness accumulation value First Data Second data Third data Historical PWM values A1 a1 b1 c1 d1％ A1 a2 b2 c2 d2％ A1 a3 b3 c3 d3％ A2 a4 b4 c4 d4％ A2 a5 b5 c5 d5％ A3 a6 b6 c6 d6％ A3 a7 b7 c7 d7％ A3 a8 b8 c8 d8％ A4 a9 b9 c9 d9％

[0127] Table 2

[0128] It should be noted that when updating the preset corresponding relationship, it is not limited to adding data in the preset corresponding relationship as mentioned above, but it is also possible to delete some data while adding data, for example, deleting data with a longer time, or deleting data with a lower frequency of use. The specific update method can be determined according to the situation, and the embodiment of the present application does not make any limitation on this.

[0129] If it is determined that the preset correspondence relationship exists with a historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value, then in the preset correspondence relationship, the historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value is determined, and the historical brightness feature data corresponding to the determined historical full-screen brightness accumulation value is compared with the current brightness feature data for similarity. If the similarity between the first data and the fourth data is 100%, the similarity between the second data and the fifth data is 100%, and the similarity between the third data and the sixth data is 100%, then it is determined that the second target PWM value exists in the preset correspondence relationship. If at least one of the above three similarities is not 100%, then the preset correspondence relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the current PWM value.

[0130] In one embodiment, after the dimming controller obtains the second target PWM value through PI adjustment, the dimming controller searches for a historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value of the current frame image from a preset corresponding relationship. If the historical full-screen brightness accumulation value does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

[0131] If it exists, then in the preset corresponding relationship, determine the historical full-screen brightness cumulative value that is the same as the current full-screen brightness cumulative value, and compare the historical brightness feature data corresponding to the determined historical full-screen brightness cumulative value with the current brightness feature data for similarity. If the similarity between the first data and the fourth data is 100%, the similarity between the second data and the fifth data is 100%, and the similarity between the third data and the sixth data is 100%, then it is determined that the second target PWM value exists in the preset corresponding relationship. If at least one of the above three similarities is not 100%, then the preset corresponding relationship is updated based on the current full-screen brightness cumulative value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

[0132] For ease of understanding, a detailed description is given below with reference to specific embodiments.

[0133] like Figure 3 FIG. 1 is a complete flow chart of a method for adjusting the output voltage of a power supply provided in an embodiment of the present application, which specifically includes the following steps:

[0134] S301, SPI receives frame synchronization signal VSYNC;

[0135] S302, SPI reads brightness data of the current image, and sends the brightness data to the dimming controller and the dimmer;

[0136] S303, the dimmer processes the received brightness data;

[0137] S304, the dimming controller searches for a first target PWM value corresponding to the backlight brightness data from a preset corresponding relationship according to the received brightness data;

[0138] S305, the dimming controller determines whether the first target PWM value is found, if so, executes S311, otherwise executes S306;

[0139] S306, the dimming controller reads the output voltage of each output port of the dimmer through single-line transmission;

[0140] S307, the dimming controller compares the output voltage with the preset voltage to determine whether the output voltage is undervoltage or overvoltage, if so, execute S308, otherwise execute S312;

[0141] When there is neither undervoltage nor overvoltage in all output voltages, S309 is executed.

[0142] S308, the dimming controller calculates the overvoltage quantity, the undervoltage quantity and the total voltage quantity;

[0143] After all output voltages are compared with a preset voltage, the number of overvoltages and the number of undervoltages, as well as the total number of output voltages, are determined.

[0144] S309, the dimming controller determines whether the undervoltage quantity is greater than a first preset threshold value, if so, execute S310, otherwise, execute S314;

[0145] The undervoltage quantity is greater than the first preset threshold value, and it is necessary to adjust the output voltage to increase.

[0146] S310, the dimming controller calculates the PWM value through PI adjustment based on the undervoltage quantity;

[0147] S311, the dimming controller outputs a PWM value, and after receiving the PWM value, the switching power supply outputs a power supply voltage based on the PWM value;

[0148] S312, the dimming controller determines whether the current PWM value exists in the preset corresponding relationship, if yes, executes S313, otherwise ends;

[0149] S313, the dimming controller updates the preset corresponding relationship based on the current PWM value;

[0150] S314, the dimming controller determines whether the overvoltage quantity is greater than a second preset threshold value, if so, execute S315, otherwise execute S313;

[0151] The number of undervoltages is less than or equal to the first preset threshold, and the number of overvoltages is greater than the second preset threshold, and the output voltage needs to be lowered.

[0152] S315 . The dimming controller calculates the PWM value based on the overvoltage quantity through PI adjustment and executes S311 .

[0153] In the embodiment of the present application, the image front-end processor sends a frame synchronization signal to the SPI, and then sends the backlight brightness data of the current frame image to the SPI, and the SPI sends the backlight brightness data to the dimmer and the dimming controller. After receiving the backlight brightness data, the dimming controller determines the full-screen brightness accumulation value, and converts the backlight brightness data into a brightness histogram, and then extracts features from the brightness histogram to obtain brightness feature data, and based on the full-screen brightness accumulation value and the brightness feature data, searches for the first target PWM value from a preset corresponding relationship;

[0154] If the first target PWM value is found, the first target PWM value is output to the switching power supply. If the first target PWM value is not found, the dimming controller determines the second target PWM value through PI adjustment based on the OPF data read by the single-line transmission, and sends the second target PWM value to the switching power supply.

[0155] In the embodiment of the present application, if there is an overvoltage or undervoltage situation, it is necessary to record the calculated second target PWM value. Then drive the switching power supply, change the power supply output voltage, and then judge whether there is a recent record of adjusting the PWM value. If there is an overvoltage or undervoltage, it is necessary to check whether there is a recent record of adjusting the PWM value. If there is an overvoltage or undervoltage, the preset corresponding relationship is updated based on the most recently adjusted PWM value. After the learning operation, the operation of this frame is terminated. Wait for the arrival of the next data.

[0156] Based on the same inventive concept, an embodiment of the present application also provides a dimming controller. The principle of the dimming controller in solving the technical problem is similar to the above-mentioned method for adjusting the power supply output voltage. The implementation of the dimming controller can refer to the implementation of the method for adjusting the power supply output voltage, and the repeated parts will not be repeated.

[0157] like Figure 4 As shown, the present application also provides a structural schematic diagram of a dimming controller, which is applied to a liquid crystal backlight panel, including:

[0158] The determination module 401 is used to determine the current full-screen brightness accumulation value and the current brightness characteristic data according to the backlight brightness data of the current frame image;

[0159] A search module 402 is used to search for a first target PWM value corresponding to the current full-screen brightness accumulated value and the current brightness characteristic data from a preset corresponding relationship, wherein the preset corresponding relationship is a corresponding relationship between a historical full-screen brightness accumulated value, a historical brightness characteristic data, and a historical PWM value, and the historical brightness characteristic data is obtained based on backlight brightness data of historical images;

[0160] The sending module 403 is used to send the first target PWM value to a switching power supply, and the switching power supply outputs a power supply voltage for powering the LEDs in the liquid crystal backlight panel based on the first target PWM value.

[0161] In one embodiment, the determining module 401 is specifically configured to:

[0162] Determine a current brightness histogram according to the backlight brightness data;

[0163] Performing feature extraction on the current brightness histogram to obtain the current brightness feature data;

[0164] The search module 402 is specifically used for:

[0165] Searching for a historical full-screen brightness accumulated value that is the same as the current full-screen brightness accumulated value from the preset corresponding relationship;

[0166] The historical brightness feature data corresponding to the historical full-screen brightness cumulative value found are compared with the current brightness feature data for similarity, and the target historical brightness feature data is determined according to the comparison result;

[0167] The historical PWM value corresponding to the target historical brightness characteristic data in the preset corresponding relationship is used as the first target PWM value.

[0168] In one embodiment, the search module 402 is specifically used to:

[0169] Calculating a first similarity between the first data and the fourth data using a gradient contrast method, calculating a second similarity between the second data and the fifth data using an absolute value of a difference, and calculating a third similarity between the third data and the sixth data using an absolute value of a difference;

[0170] For each historical brightness feature data found, respectively calculate the sum of the first similarity, the second similarity and the third similarity, and use the historical brightness feature data corresponding to the maximum sum value among the historical brightness feature data as the target historical brightness feature data;

[0171] Among them, the historical brightness feature data includes first data representing histogram equalization, second data representing the accumulated value of each row of brightness data, and third data representing the accumulated value of each column of brightness, and the current brightness feature data includes fourth data representing histogram equalization, fifth data representing the accumulated value of each row of brightness data, and sixth data representing the accumulated value of each column of brightness.

[0172] In one embodiment, the preset corresponding relationship is obtained by:

[0173] According to the backlight brightness data of the historical frame image, determine the historical brightness histogram and the historical full-screen brightness accumulation value;

[0174] Performing feature extraction on the historical brightness histogram to obtain historical brightness feature data;

[0175] The historical full-screen brightness accumulated value, the historical brightness characteristic data and the PWM value corresponding to the historical frame image are used as the preset corresponding relationship.

[0176] In one embodiment, the search module 402 is specifically used to:

[0177] If the first target PWM value is not found from the preset corresponding relationship, a second target PWM value is obtained by adopting PI regulation according to the output voltage of the driving port of each dimmer;

[0178] The sending module is also used for:

[0179] The second target PWM value is sent to the switching power supply, and the switching power supply outputs a power supply voltage based on the second target PWM value.

[0180] In one embodiment, after obtaining the second target PWM value, the search module 402 is further configured to:

[0181] Searching for a historical full-screen brightness accumulation value that is the same as a current full-screen brightness accumulation value of a current frame image from the preset corresponding relationship;

[0182] If it is determined that it does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

[0183] In one embodiment, the determining module 401 is further configured to:

[0184] According to the output voltage of the output port of each dimmer, determine to maintain the current PWM value;

[0185] The search module 402 is also used for:

[0186] Searching for a historical full-screen brightness accumulation value that is the same as a current full-screen brightness accumulation value of a current frame image from the preset corresponding relationship;

[0187] If it is determined that it does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the current output PWM value.

[0188] Based on the same inventive concept, the embodiment of the present application also provides a liquid crystal backlight system. The principle of solving the technical problem of the liquid crystal backlight system is similar to the above-mentioned method of adjusting the power supply output voltage. The implementation of the liquid crystal backlight system can refer to the implementation of the method of adjusting the power supply output voltage, and the repeated parts will not be repeated.

[0189] The present application also provides a backlight system, comprising a liquid crystal backlight panel, a switching power supply and a dimming controller as described above, wherein the liquid crystal backlight panel comprises a dimmer and an LED;

[0190] The dimming controller, the switching power supply, the LED and the dimmer are connected in sequence, and the dimming controller is also electrically connected to the dimmer.

[0191] The embodiment of the present application provides a method for adjusting the output voltage of a power supply, a dimming controller, and a backlight system. The dimming controller first determines the current full-screen brightness accumulation value and the current brightness characteristic data according to the backlight brightness data of the current frame image, and then searches for a first target PWM value corresponding to the current full-screen brightness accumulation value and the current brightness characteristic data from a preset correspondence relationship, and the switching power supply outputs the power supply voltage based on the first target PWM value. Since the output power supply voltage is based on the PWM value found from the preset correspondence relationship, compared with repeatedly adjusting the power supply output voltage according to the display brightness of multiple frames of images, the current picture and the backlight picture can be synchronized to improve the display effect.

[0192] The present application is described above with reference to the block diagrams and / or flow charts showing the methods, devices (systems) and / or computer program products according to the embodiments of the present application. It should be understood that a block of the block diagram and / or flow chart diagram and a combination of blocks of the block diagram and / or flow chart diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer and / or other programmable data processing device to produce a machine, so that the instructions executed by the computer processor and / or other programmable data processing device create a method for implementing the functions / actions specified in the block diagram and / or flow chart block.

[0193] Accordingly, the present application may also be implemented with hardware and / or software (including firmware, resident software, microcode, etc.). Furthermore, the present application may take the form of a computer program product on a computer-usable or computer-readable storage medium, which has a computer-usable or computer-readable program code implemented in the medium, for use by an instruction execution system or in conjunction with an instruction execution system. In the context of the present application, a computer-usable or computer-readable medium may be any medium that may contain, store, communicate, transmit, or convey a program for use by an instruction execution system, device, or apparatus, or in conjunction with an instruction execution system, device, or apparatus.

[0194] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for adjusting the output voltage of a power supply, characterized in that: Applied to a liquid crystal backlight panel, the method comprises: The dimming controller determines the current full-screen brightness accumulation value according to the backlight brightness data of the current frame image, and the dimming controller determines the current brightness histogram according to the backlight brightness data, performs feature extraction on the current brightness histogram, and obtains current brightness feature data; The dimming controller searches for a historical full-screen brightness accumulated value that is the same as the current full-screen brightness accumulated value from a preset corresponding relationship, wherein the preset corresponding relationship is a corresponding relationship between the historical full-screen brightness accumulated value, the historical brightness characteristic data, and the historical PWM value; The dimming controller uses a gradient contrast method to calculate a first similarity between the first data and the fourth data, and uses an absolute value of a difference to calculate a second similarity between the second data and the fifth data, and uses an absolute value of a difference to calculate a third similarity between the third data and the sixth data, wherein the historical brightness feature data includes first data representing histogram equalization, second data representing an accumulated value of brightness data of each row, and third data representing an accumulated value of brightness of each column, and the current brightness feature data includes fourth data representing histogram equalization, fifth data representing an accumulated value of brightness data of each row, and sixth data representing an accumulated value of brightness of each column, and the historical brightness feature data is obtained based on backlight brightness data of historical images; The dimming controller calculates the sum of the first similarity, the second similarity and the third similarity for each historical brightness feature data found, and uses the historical brightness feature data corresponding to the maximum sum value among the historical brightness feature data as the target historical brightness feature data; The dimming controller uses the historical PWM value corresponding to the target historical brightness characteristic data in the preset corresponding relationship as the first target PWM value; The dimming controller sends the first target PWM value to a switching power supply, and the switching power supply outputs a power supply voltage for powering an LED in a liquid crystal backlight panel based on the first target PWM value.

2. The method according to claim 1, characterized in that The preset corresponding relationship is obtained by: The dimming controller determines a historical brightness histogram and a historical full-screen brightness accumulation value according to the backlight brightness data of the historical frame image; The dimming controller extracts features from the historical brightness histogram to obtain historical brightness feature data; The dimming controller uses the historical full-screen brightness accumulation value, the historical brightness characteristic data, and the PWM value corresponding to the historical frame image as the preset corresponding relationship.

3. The method according to claim 1, characterized in that The method further includes: If the first target PWM value is not found from the preset corresponding relationship, the dimming controller adopts PI regulation according to the output voltage of the driving port of each dimmer to obtain a second target PWM value; The dimming controller sends the second target PWM value to the switching power supply, and the switching power supply outputs a power supply voltage based on the second target PWM value.

4. The method according to claim 3, characterized in that After the dimming controller obtains the second target PWM value, the method further includes: The dimming controller searches the preset corresponding relationship for a historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value of the current frame image; If it is determined that it does not exist, the dimming controller updates the preset corresponding relationship based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

5. The method according to claim 3, characterized in that The method further comprises: The dimming controller determines to maintain the current PWM value according to the output voltage of the output port of each dimmer; The dimming controller searches the preset corresponding relationship for a historical full-screen brightness accumulation value that is the same as the current full-screen brightness accumulation value of the current frame image; If it is determined that it does not exist, the dimming controller updates the preset corresponding relationship based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the currently output PWM value.

6. A dimming controller, characterized in that: Applied to LCD backlight panels, including: A determination module, used to determine the current full-screen brightness accumulation value according to the backlight brightness data of the current frame image, and to determine the current brightness histogram according to the backlight brightness data, and to perform feature extraction on the current brightness histogram to obtain current brightness feature data; A search module, used to search for a first target PWM value corresponding to the current full-screen brightness accumulated value and the current brightness characteristic data from a preset corresponding relationship, wherein the preset corresponding relationship is a corresponding relationship between a historical full-screen brightness accumulated value, a historical brightness characteristic data, and a historical PWM value, and the historical brightness characteristic data is obtained based on backlight brightness data of historical images; a sending module, configured to send the first target PWM value to a switching power supply, wherein the switching power supply outputs a power supply voltage for powering an LED in a liquid crystal backlight panel based on the first target PWM value; Wherein, the search module is specifically used for: Searching for a historical full-screen brightness accumulated value that is the same as the current full-screen brightness accumulated value from the preset corresponding relationship; The historical brightness feature data corresponding to the historical full-screen brightness cumulative value found are compared with the current brightness feature data for similarity, and the target historical brightness feature data is determined according to the comparison result; Using the historical PWM value corresponding to the target historical brightness characteristic data in the preset corresponding relationship as the first target PWM value; The search module is specifically used for: Calculating a first similarity between the first data and the fourth data using a gradient contrast method, calculating a second similarity between the second data and the fifth data using an absolute value of a difference, and calculating a third similarity between the third data and the sixth data using an absolute value of a difference; For each historical brightness feature data found, respectively calculate the sum of the first similarity, the second similarity and the third similarity, and use the historical brightness feature data corresponding to the maximum sum value among the historical brightness feature data as the target historical brightness feature data; Among them, the historical brightness feature data includes first data representing histogram equalization, second data representing the accumulated value of each row of brightness data, and third data representing the accumulated value of each column of brightness, and the current brightness feature data includes fourth data representing histogram equalization, fifth data representing the accumulated value of each row of brightness data, and sixth data representing the accumulated value of each column of brightness.

7. The dimming controller according to claim 6, characterized in that: The preset corresponding relationship is obtained by: According to the backlight brightness data of the historical frame image, determine the historical brightness histogram and the historical full-screen brightness accumulation value; Performing feature extraction on the historical brightness histogram to obtain historical brightness feature data; The historical full-screen brightness accumulated value, the historical brightness characteristic data and the PWM value corresponding to the historical frame image are used as the preset corresponding relationship.

8. The dimming controller according to claim 6, characterized in that: The search module is specifically used for: If the first target PWM value is not found from the preset corresponding relationship, a second target PWM value is obtained by adopting PI regulation according to the output voltage of the driving port of each dimmer; The sending module is also used for: The second target PWM value is sent to the switching power supply, and the switching power supply outputs a power supply voltage based on the second target PWM value.

9. The dimming controller according to claim 8, characterized in that: After obtaining the second target PWM value, the search module is further used for: Searching for a historical full-screen brightness accumulation value that is the same as a current full-screen brightness accumulation value of a current frame image from the preset corresponding relationship; If it is determined that it does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulated value, the current brightness feature data corresponding to the current frame image, and the second target PWM value.

10. The dimming controller according to claim 8, characterized in that: The determining module is also used for: According to the output voltage of the output port of each dimmer, determine to maintain the current PWM value; The search module is also used to: Searching for a historical full-screen brightness accumulation value that is the same as a current full-screen brightness accumulation value of a current frame image from the preset corresponding relationship; If it is determined that it does not exist, the preset corresponding relationship is updated based on the current full-screen brightness accumulation value, the current brightness feature data corresponding to the current frame image, and the current output PWM value.

11. A backlight system, characterized in that: It comprises a liquid crystal backlight panel, a switching power supply and a dimming controller as claimed in any one of claims 6 to 10, wherein the liquid crystal backlight panel comprises a dimmer and an LED; The dimming controller, the switching power supply, the LED and the dimmer are connected in sequence, and the dimming controller is also electrically connected to the dimmer.

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