LED dimming method, LED dimming circuit and electronic equipment

Abstract

The present application relates to the field of electronic technology and discloses an LED dimming method, an LED dimming circuit, and an electronic device. The dimming method uses a relationship between the brightness of an LED and the adjustment time to adjust the brightness of the LED. In this relationship, the growth rate of the current or voltage input to the LED, that is, the growth rate of the LED brightness, gradually increases and then gradually decreases as the adjustment time increases. This ensures that the brightness of the LED increases slowly at the initial brightness and when the brightness of the LED is close to the target brightness, without causing overshoot to the human eye, which is conducive to improving the user experience.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to an LED dimming method, an LED dimming circuit and an electronic device. Background Art

[0002] The widespread adoption of mobile devices has led to an explosive growth in the number of liquid crystal display (LCD) screens, and people's expectations for LCD display quality are also increasing. In practice, the increase in mobile device screen size has led to an exponential increase in the number of light-emitting diodes (LEDs) in LCD backlights, from the traditional 12 to 36 or more. While more LEDs increase brightness, they also place higher demands on display detail, such as the initial 9-bit dimming requirement, which has gradually increased to 11-bit and even higher dimming accuracy.

[0003] In practical applications, finer dimming can provide a better user experience, but it can also introduce risks such as screen flicker. Backlight flicker generally occurs when the backlight is fixed at a certain brightness level, but the screen brightness fluctuates continuously, resulting in a poor user experience. This can be caused by insufficient input PWM precision and excessive jitter, causing the device to interpret the brightness as fluctuating between two levels at a given brightness level. Summary of the Invention

[0004] In view of this, embodiments of the present application provide an LED dimming method, LED dimming circuit, and electronic device. The LED brightness is adjusted by using a relationship between the LED brightness and the adjustment time. In this relationship, the rate of increase of the current or voltage input to the LED, and therefore the rate of increase of the LED brightness, gradually increases and then gradually decreases as the adjustment time increases. This ensures that the LED brightness increases slowly both at the initial brightness and when the LED brightness is close to the target brightness, preventing overshoot to the human eye and improving the user experience.

[0005] In a first aspect, an embodiment of the present application provides an LED dimming method, the method comprising:

[0006] Obtain the current brightness and the first target brightness of the LED, wherein the first target brightness is greater than the current brightness;

[0007] Determine Q intermediate brightnesses between the current brightness and the first target brightness, wherein the increasing speed of the Q intermediate brightnesses first increases and then decreases as Q increases;

[0008] The brightness of the LED is adjusted sequentially to the kth brightness among Q intermediate brightnesses, where 1≤k≤Q.

[0009] That is to say, in the process of adjusting the brightness of the LED from the current brightness to the first target brightness, the increasing rate of the LED brightness first increases and then decreases during the adjustment process, so that when the adjustment is just started and the brightness of the LED approaches the first target brightness, the increasing rate of the LED brightness is relatively small, so as not to cause overshoot to the human eye, which is beneficial to improving the user experience.

[0010] In a possible implementation of the first aspect, the increasing speed of the first N intermediate brightnesses of the Q intermediate brightnesses increases as Q increases, and the increasing speed of the last QN intermediate brightnesses decreases as Q increases.

[0011] In a possible implementation of the first aspect, the Q intermediate brightnesses are determined by the following formula:

[0012]

[0013] Among them, CODE(k) is the brightness code corresponding to the kth intermediate brightness; CODE(k-1) is the brightness code corresponding to the k-1th intermediate brightness; A is the adjustment coefficient, and A>1; Code_IN(k)=(Code_H-Code_0)×k / N+Code_0, Code_0 is the brightness code corresponding to the current brightness, Code_H is the brightness code corresponding to the first target brightness; CODE(0)=Code_0.

[0014] In a possible implementation of the first aspect, the adjustment coefficient A is determined by the following formula:

[0015] A=(Code_H-Code_0)×B / F_CODE,

[0016] Among them, F_CODE is the value range of brightness coding, and B is the preset coefficient.

[0017] That is, the adjustment coefficient A is dynamically adjusted as the difference between the first target brightness and the current brightness (Code_H-Code_0) changes, so that the change pattern of the LED brightness increase rate is similar for different adjustment ranges, which is conducive to improving user experience.

[0018] In a possible implementation of the first aspect, sequentially adjusting the brightness of the LEDs to the kth brightness among the Q intermediate brightnesses includes:

[0019] The brightness code CODE(k) corresponding to the k-th brightness among the Q intermediate brightnesses is converted into the corresponding current or voltage in sequence, and the corresponding current or voltage is input to the LED.

[0020] In a second aspect, an embodiment of the present application provides an LED dimming circuit, which includes a brightness code generation circuit and a digital-to-analog conversion circuit, wherein:

[0021] a brightness code generating circuit, configured to generate, upon receiving a current brightness code corresponding to the current brightness of the LED and a first target brightness code corresponding to the first target brightness, Q intermediate brightness codes between the current brightness code and the first target brightness code, wherein an increase rate of the Q intermediate brightness codes first increases and then decreases as Q increases;

[0022] The digital-to-analog conversion circuit is used to sequentially convert Q intermediate brightness codes into corresponding voltages or currents and output them to the LEDs.

[0023] That is to say, when the LED dimming circuit adjusts the brightness of the LED from the current brightness to the first target brightness, the increasing rate of the LED brightness first increases and then decreases during the adjustment process, so that when the adjustment is just started and the brightness of the LED approaches the first target brightness, the increasing rate of the LED brightness is relatively small, so as not to cause overshoot to the human eye, which is beneficial to improving the user experience.

[0024] In a possible implementation of the second aspect, the increasing speed of the first N intermediate brightness codes of the Q intermediate brightness codes increases as Q increases, and the increasing speed of the last QN intermediate brightness codes decreases as Q increases.

[0025] In a possible implementation of the second aspect, the luminance code generation circuit determines the Q intermediate luminance codes based on the following formula:

[0026]

[0027] Among them, CODE(k) is the kth intermediate brightness code; CODE(k-1) is the k-1th intermediate brightness code; A is the adjustment coefficient, and A>1; Code_IN(k)=(Code_H-Code_0)×k / N+Code_0, Code_0 is the current brightness code, Code_H is the first target brightness code; CODE(0)=Code_0.

[0028] In a possible implementation of the second aspect, the adjustment coefficient A is determined by the following formula:

[0029] A=(Code_H-Code_0)×B / F_CODE,

[0030] Among them, F_CODE is the value range of brightness coding, and B is the preset coefficient.

[0031] That is, the LED dimming circuit dynamically adjusts the adjustment coefficient A according to the difference between the first target brightness and the current brightness (Code_H-Code_0), so that the change pattern of the LED brightness increase rate is similar for different adjustment ranges, which is conducive to improving user experience.

[0032] In a possible implementation of the second aspect, the LED dimming circuit further includes a timing control circuit configured to periodically generate a clock signal; and the brightness code generation circuit generates an intermediate brightness code each time a clock signal is received.

[0033] In a possible implementation of the second aspect, the brightness code generation circuit includes a first brightness coding subcircuit and a second brightness coding subcircuit;

[0034] The first luminance encoding subcircuit receives the current luminance code and the first target luminance code, and upon receiving the kth clock signal, generates and outputs Code_IN(k) to the second luminance encoding subcircuit;

[0035] The second brightness coding sub-circuit is used to generate the kth intermediate brightness code CODE(k) and output it to the digital-to-analog conversion circuit when receiving the kth clock signal.

[0036] In some implementations, the first brightness encoding subcircuit may be, for example, the instruction brightness code generation circuit 402 described below, and the second brightness encoding subcircuit may be, for example, the adjustment brightness code generation circuit 403 described below.

[0037] In a possible implementation of the second aspect, the first brightness encoding subcircuit includes: a first subtractor, a first buffer, a first divider, a first adder, and a second buffer; wherein,

[0038] The input end of the first subtractor is used to receive the current brightness code and the first target brightness code, the output end is connected to the input end of the first cache, the output end of the first cache is connected to an input end of the first divider, the other input end of the first divider is used to receive Q, the output end is connected to an input end of the first adder, the other input end of the first adder is connected to the output end of the second cache, the output end is connected to the input end of the second cache, and the output end of the second cache is used to output Code_IN(k).

[0039] In some implementations, the first subtractor may be, for example, the subtractor 501 described below, the first cache may be, for example, the adjustment range cache 502 described below, the first divider may be, for example, the divider 503 described below, the first adder may be, for example, the adder 504 described below, and the second cache may be, for example, the instruction brightness encoding cache 505 described below.

[0040] In a possible implementation of the second aspect, the second luminance encoding subcircuit includes: a second subtractor, a second divider, a third buffer, a third divider, a second adder, and a fourth buffer; wherein,

[0041] One input end of the second subtractor is connected to the output end of the second cache, another input end is connected to the output end of the fourth cache, and the output end is connected to one input end of the third divider. One input end of the second divider is connected to the output end of the first cache, another input end is used to receive the quotient of F_CODE divided by B, and the output end is connected to the input end of the third cache. The output end of the third cache is connected to another input end of the third divider. The output end of the third divider is connected to one input end of the second adder. Another input end of the second adder is connected to the output end of the fourth cache, and the output end is connected to the output end of the fourth cache. The output end of the fourth cache is connected to the digital-to-analog conversion circuit.

[0042] In some implementations, the second subtractor may be, for example, the subtractor 506 described below, the second divider may be, for example, the divider 507 described below, the third cache may be, for example, the adjustment coefficient cache 508 described below, the third divider may be, for example, the divider 509 described below, the second adder may be, for example, the adder 510 described below, and the fourth cache may be, for example, the adjustment brightness coding cache 511 described below.

[0043] In a third aspect, an embodiment of the present application provides an electronic device comprising: an LED; a memory storing instructions; and at least one processor for executing instructions to adjust the brightness of the LED through the LED dimming method provided by the first aspect and any possible implementation of the first aspect.

[0044] In a fourth aspect, an embodiment of the present application provides an electronic device, comprising the LED dimming circuit provided by the second aspect and any possible implementation of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 1 is a diagram showing an application scenario of LED dimming according to some embodiments of the present application;

[0046] Figure 2 (a) and Figure 2 (b) is a schematic diagram showing a curve of LED dimming according to some embodiments of the present application;

[0047] Figure 3 1 is a schematic diagram showing a curve of linear dimming and exponential dimming of an LED according to some embodiments of the present application;

[0048] Figure 4is a module schematic diagram showing an LED dimming circuit 400 according to some embodiments of the present application;

[0049] Figure 5 1 is a schematic diagram showing a specific implementation circuit of each module in an LED dimming circuit 400 according to some embodiments of the present application;

[0050] Figure 6 is a schematic diagram showing a flow chart of an LED dimming method according to some embodiments of the present application;

[0051] Figure 7 1 is a schematic diagram showing a curve of LED linear dimming, exponential dimming and dimming of the present application according to some embodiments of the present application;

[0052] Figure 8 According to some embodiments of the present application, another curve diagram of LED linear dimming, exponential dimming and dimming of the present application is shown. DETAILED DESCRIPTION

[0053] To better understand the solutions of the embodiments of the present application, the following first introduces the relevant terms and concepts that may be involved in the embodiments of the present application:

[0054] (1) Luminance coding

[0055] Brightness coding is usually represented by an N-bit binary number, which is used to map the brightness range of the LED to 0 to 2 N The larger the number N, the more possible brightness code values ​​there are, and the higher the precision of LED brightness adjustment. Different dimming methods have different mappings between brightness codes and LED brightness or drive current. By inputting the brightness code to the LED driver circuit, the driver converts the brightness code into a corresponding current or voltage to adjust the LED brightness accordingly.

[0056] The specific solutions of the embodiments of the present application are introduced below with reference to the accompanying drawings.

[0057] It is understood that the brightness adjustment method and circuit provided in the embodiments of the present application can be applied to scenarios where the brightness of any LED is adjusted. For example, they can be applied to terminal devices such as mobile phones, tablet computers, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptop computers, ultra-mobile personal computers (UMPCs), netbooks, and personal digital assistants (PDAs). The embodiments of the present application do not impose any restrictions on the specific type of terminal device. For ease of description, the technical solution of the present application is described below using LEDs as the backlight source of an LCD screen as an example.

[0058] As mentioned above, LCD realizes the display function by illuminating the liquid crystal with the backlight source of the backlight layer. For example, Figure 1 The LCD screen of an electronic device realizes the display function of the LCD screen by illuminating the liquid crystal with a large number of LEDs in the backlight layer.

[0059] When the brightness of the LED is increased from the initial brightness to the target brightness, the brightness of the LED will jump, and the display brightness of the LCD will jump, causing screen flickering and affecting the user experience. Figure 2 (a), assuming that at time t1, the brightness of the LED is adjusted from the initial brightness a to the target brightness b, the brightness of the LED will jump directly, which may cause the LCD screen to flicker, affecting the user experience. To avoid the LED brightness jumping when the brightness of the LED is adjusted from the initial brightness to the target brightness, in some embodiments, a linear dimming method can be used to adjust the brightness of the LED. For example, refer to Figure 2 (b) Assuming that at time t1, the LED brightness is adjusted from the initial brightness a, and at time t2, the LED reaches the target brightness b, then with linear dimming, the LED brightness will increase linearly. However, when dimming begins at the initial brightness a at time t1, linear dimming suffers from an uneven brightness increase, which cannot meet the human eye's adaptation requirements. Therefore, in some embodiments, exponential dimming can be used to adjust the LED brightness.

[0060] Specifically, Figure 3 According to some embodiments of the present application, a schematic diagram is shown showing the relationship between the LED current and the brightness code when the LED brightness is adjusted using linear dimming and exponential dimming.

[0061] like Figure 3As shown, assuming that the brightness code is 11 bits as an example (that is, the brightness code value is 0-2047, with a total of 2048 values), the brightness code corresponding to the initial brightness is 0, and the brightness code corresponding to the target brightness is 2047. Corresponding to linear dimming, the mapping relationship between the brightness code and the LED current is a linear relationship. In the process of increasing the brightness code from 0 to 2047, the LED current increases linearly from 0mA to 30mA, and the slope of the LED current remains unchanged, that is, the growth rate of the LED brightness remains unchanged; however, at low brightness, linear dimming has the problem of non-smooth brightness growth, which cannot meet the adaptation needs of the human eye. Based on this, in some embodiments, an exponential dimming method can be used to adjust the brightness of the LED. As Figure 3 As shown, exponential dimming has an exponential relationship with the brightness code and the LED current. The LED current increases exponentially with increasing brightness code, which means the LED brightness increases exponentially. At low brightness, the LED current increases slowly with exponential dimming, which in turn increases the LED brightness, resulting in a more comfortable viewing experience for the human eye. However, when adjusting the LED brightness at high brightness, for example, when the brightness code is increased from 1792 to 2047, the LED current increases too quickly, which means the LED brightness changes too quickly, causing visual overshoot and affecting the user's visual experience.

[0062] Based on this, an embodiment of the present application provides a dimming method, in which the brightness of the LED is adjusted by using another relationship between the brightness of the LED and the adjustment time. In this relationship, the growth rate of the LED current (that is, the growth rate of the LED brightness) first gradually increases and then gradually decreases as the adjustment time increases. In this way, it can be ensured that at the initial brightness, the current of the LED gradually increases (that is, the brightness of the LED gradually increases), and the brightness of the LED slowly increases, meeting the adaptation needs of the human eye. In addition, because the growth rate of the LED current gradually decreases (that is, the growth rate of the LED brightness gradually decreases) when the brightness of the LED is closer to the target brightness, it will not cause overshoot to the human eye, which is conducive to improving the user experience.

[0063] For example, in some embodiments, the process of adjusting the brightness of an LED from low brightness (brightness code is Code_0) to high brightness (Code_H) can be divided into N+M adjustments, and the brightness code CODE(n) during the nth adjustment can be based on the following formula (1).

[0064]

[0065] Among them, CODE(n) is the brightness code input to the driving circuit for the nth adjustment; CODE(n-1) is the brightness code input to the driving circuit for the n-1th adjustment; Code_IN(n)=(Code_H-Code_0)×n / N+code(0); A is the adjustment coefficient, A>1; CODE(0)=Code_0; CODE(N) is the brightness code input to the driving circuit for the Nth adjustment.

[0066] Based on the adjustment curve determined by formula (1), during the first N adjustments, the rate of increase of CODE(n) gradually increases with the increase of the number of adjustments n, while during the subsequent M adjustments, the rate of increase of CODE(n) gradually decreases with the increase of the number of adjustments n. As a result, the rate of increase of the LED brightness will first gradually increase and then gradually decrease with the increase of the number of adjustments n. Moreover, when the LED brightness is low, the rate of increase of the LED brightness gradually increases, so that the LED brightness increases slowly, meeting the adaptation needs of the human eye; when the LED brightness is high, the rate of increase of the LED brightness gradually decreases, so that the LED brightness gradually increases, which will not cause visual overshoot to the human eye and is conducive to improving the user experience.

[0067] As can be seen from the formula for CODE_IN(n), CODE_IN(n) changes with the adjustment range (Code_H - Code_0), resulting in different adjustment curves for different adjustment ranges. To ensure that the same adjustment curve can be used to adjust the LED brightness across different adjustment ranges, in some embodiments, the adjustment coefficient A can be determined using the following formula (2).

[0068] A=(Code_H-Code_0)×B / F_CODE (2)

[0069] Among them, F_CODE is the value range of brightness coding, and B is the preset coefficient.

[0070] For example, F_CODE is 0 to 4096, B is 256, and the adjustment range is Code_H-Code_0=4096. According to formula (2), the value of the adjustment coefficient A is 256;

[0071] For another example, F_CODE is 0 to 4096, B is 256, and the adjustment range is Code_H-Code_0=2048. According to formula (2), the value of the adjustment coefficient A is 128;

[0072] For another example, F_CODE is 0 to 4096, B is 256, and the adjustment range is Code_H-Code_0=1024. According to formula (2), the value of the adjustment coefficient A is 64;

[0073] In actual applications, different adjustment ranges (Code_H-Code_0) will cause the driver circuit to output different adjustment curves. In order to ensure that the same adjustment curve can be used to adjust the brightness of the LED for different adjustment ranges, in some embodiments, the adjustment coefficient A can be determined by the following formula (2). Among them, the preset coefficient B can be selected according to the actual dimming effect. In order to facilitate circuit implementation, the preset coefficient B is usually selected as 2 Q (Q>1), for example, B can be 256, 512, 1024, etc.

[0074] The following introduces a dimming circuit for realizing the adjustment curve determined by the above formula (1) and formula (2).

[0075] For the convenience of description, CODE(n) in formula (1) is called the adjustment brightness code, CODE(n-1) is called the current brightness code, and CODE_IN(n) is called the instruction brightness code.

[0076] Specifically, Figure 4 1 is a module schematic diagram showing an LED dimming circuit 400 according to some embodiments of the present application.

[0077] like Figure 4 As shown, the schematic diagram of the LED dimming circuit 400 may include a timing control circuit 401 , an instruction brightness code generation circuit 402 , an adjustment brightness code generation circuit 403 and a digital-to-analog conversion module 404 .

[0078] The timing control circuit 401 is used to generate clock signals for instructing the brightness code generation circuit 402 and adjusting the brightness code generation circuit 403 , and each clock cycle corresponds to one adjustment.

[0079] The command brightness code generating circuit 402 is used to generate the command brightness code CODE_IN(n) in the aforementioned formula (1) according to the adjustment range, that is, Code_H-Code_0 corresponding to the formula (1).

[0080] The adjustment brightness code generation circuit 403 generates the adjustment brightness code CODE(n) corresponding to the nth adjustment based on the clock signal of the timing control circuit 401 and the instruction brightness code CODE_IN(n) generated by the instruction brightness code generation circuit 402 in each clock cycle based on formula (1) and formula (2), and outputs it to the digital-to-analog conversion module 404.

[0081] The digital-to-analog conversion module 404 is used to receive the brightness adjustment code CODE(n) output by the brightness adjustment code generation circuit 403, and output the current or voltage corresponding to the brightness adjustment code CODE(n) to the LED to adjust the brightness of the LED to the brightness corresponding to the brightness adjustment code CODE(n).

[0082] Based on the above-described LED dimming circuit 400, since the rate of increase of the brightness code is gradually increased and then gradually decreased, the voltage or current output to the LED by the digital-to-analog conversion module 404 also gradually increases and then gradually decreases. Therefore, when adjusting the brightness of the LED from the initial brightness to the target brightness, when the LED brightness is low, the rate of increase of the LED brightness is gradually increased, thereby slowly increasing the LED brightness and meeting the adaptation requirements of the human eye. When the LED brightness is high, the rate of increase of the LED brightness is gradually decreased, thereby gradually increasing the LED brightness, preventing visual overshoot to the human eye and improving the user experience.

[0083] further, Figure 5 4 is a schematic diagram showing a specific implementation circuit of each module in an LED dimming circuit 400 according to some embodiments of the present application.

[0084] like Figure 5 As shown, in some embodiments, the instruction brightness code generation circuit 402 may include a subtractor 501 , an adjustment range buffer 502 , a divider 503 , an adder 504 , and an instruction brightness code buffer 505 .

[0085] Subtractor 501 has input terminal O1 for receiving the current brightness code, input terminal O2 for receiving the target brightness code, and an output terminal connected to adjustment range buffer 502. The output terminal provides adjustment range buffer 502 with the difference between the target brightness code at input terminal O2 and the current brightness code at input terminal O1. This difference represents the adjustment range. In other words, subtractor 501 is used to implement the (Code_H - Code_0) operation in formula (1). It is understood that subtractor 501 updates the difference between the target brightness code and the current brightness code into adjustment range buffer 502 only when the target brightness code changes.

[0086] The input end of the adjustment range buffer 502 is used to receive and store the adjustment range from the output end of the subtractor 501, and the output end of the adjustment range buffer 502 is connected to the input end 01 of the divider 503, and to the input end 01 of the divider 507, for providing the adjustment range to the input end 01 of the divider 503 and the input end 01 of the divider 507.

[0087] Input terminal 01 of divider 503 is used to receive the adjustment range from brightness adjustment buffer 502, input terminal 02 is used to receive the number of adjustments of the LED dimming circuit, and output terminal 02 is connected to input terminal 02 of adder 504. The quotient of input terminal 01 of divider 503 divided by input terminal 02 is output to input terminal 02 of adder 504. This quotient is the increment of the command brightness code of the previous adjustment compared to the command brightness code of the next adjustment (hereinafter referred to as the adjustment step size). In other words, divider 503 is used to implement (Code_H - Code_0) / N in the aforementioned formula (1).

[0088] The input end 01 of the adder 504 is used to receive the current instruction brightness code from the instruction brightness code cache 505, and the input end 02 is used to receive the adjustment step size from the output end of the divider 503. The output end is connected to the instruction brightness code cache 505, and when the next clock signal arrives, the sum of the current instruction brightness code and the adjustment step size is provided to the instruction brightness code cache 505, which is the instruction brightness code for the next adjustment.

[0089] The input end of the instruction brightness code buffer 505 is used to receive and store the instruction brightness code from the adder 504 , and the output end is used to connect to the input end 02 of the subtractor 506 to provide the instruction brightness code to the subtractor 506 .

[0090] Therefore, when the command brightness code generating circuit 402 receives the target brightness code (Code_H), it obtains the command brightness code (CODE_IN(n)) for each adjustment cycle based on the above formula (1).

[0091] The adjusted brightness code generation circuit 403 includes a subtractor 506 , a divider 507 , an adjustment coefficient buffer 508 , a divider 509 , an adder 510 , and an adjusted brightness code buffer 511 .

[0092] The input end 01 of the subtractor 506 is used to receive the current brightness code, the input end 02 is used to receive the instruction brightness code from the instruction brightness code cache 505, and the output end is used to connect the input end 01 of the divider 509, and provide the difference between the instruction brightness code and the current brightness code to the input end 01 of the divider 509, that is, to implement the (CODE_IN(n)-CODE(n-1)) in formula (1). In other words, the subtractor 506 is used to implement the (CODE_IN(n)-CODE(n-1)) in formula (1).

[0093] Input terminal 01 of divider 507 is used to receive the adjustment range from the output terminal of adjustment range buffer 502, and input terminal 02 is used to receive the quotient of the brightness code value range divided by the preset coefficient, that is, (F_CODE / B) in formula (2). The output terminal is used to connect to adjustment coefficient buffer 508 to output the quotient of the adjustment range divided by the above quotient, that is, adjustment coefficient A, to adjustment coefficient buffer 508, thereby realizing A = (Code_H - Code_0) × B / F_CODE in the above formula (2). In other words, divider 507 is used to implement adjustment coefficient A in formula (1).

[0094] The input end of the adjustment coefficient buffer 508 is used to receive and store the adjustment coefficient A from the output end of the divider 507 , and the output end is used to connect to the input end O2 of the divider 509 to provide the adjustment coefficient A to the input end O2 of the divider 509 .

[0095] The input terminal 01 of the divider 509 is used to receive the value of (CODE_IN(n)-CODE(n-1)) in formula (1) from the output terminal of the subtractor 506, the input terminal 02 is used to receive the adjustment coefficient A from the output terminal of the adjustment coefficient cache 508, and the output terminal is used to connect to the input terminal 02 of the adder 510, and provide the quotient of the difference between the instruction brightness code and the current brightness code divided by the adjustment coefficient to the input terminal 02 of the adder 510, that is, (CODE_IN(n)-CODE(n-1)) / A in formula (1). The quotient value is the increment of the adjustment brightness code of the previous adjustment compared to the adjustment brightness code of the next adjustment.

[0096] The adder 510 has an input terminal 01 for receiving the current brightness code, an input terminal 02 for receiving the previously adjusted brightness code and an increment compared to the subsequently adjusted brightness code. The adder 510's output terminal is connected to the adjusted brightness code buffer 511 and is used to provide the sum of the current brightness code and the increment (i.e., the adjusted brightness code) to the adjusted brightness code buffer 511. In other words, the adder 510 is used to implement CODE(n) in formula (1).

[0097] The input end of the brightness adjustment code buffer 511 is used to receive and store the brightness adjustment code from the output end of the adder 510, and the output end is used to connect to the digital-to-analog conversion module 404 to provide the brightness adjustment code, i.e., CODE(n) in formula (1), to the digital-to-analog conversion module 404.

[0098] The adjustment brightness code generation circuit 403 obtains the instruction brightness code (CODE_IN(n)) from the instruction brightness code generation circuit 402 and obtains the adjustment brightness code CODE(n) of each adjustment cycle based on the above formula (1).

[0099] The digital-to-analog conversion module 404 is used to receive the brightness adjustment code CODE(n) output by the brightness adjustment code generation circuit 403, and output the current or voltage corresponding to the brightness adjustment code CODE(n) to the LED to adjust the brightness of the LED to the brightness corresponding to the brightness adjustment code CODE(n).

[0100] Based on the above-described LED dimming circuit 500, since the rate of increase of the brightness code is gradually increased and then gradually decreased, the voltage or current output to the LED by the digital-to-analog conversion module 404 also gradually increases and then gradually decreases. Therefore, when adjusting the brightness of the LED from the initial brightness to the target brightness, when the LED brightness is low, the rate of increase of the LED brightness is gradually increased, thereby slowly increasing the LED brightness and meeting the adaptation requirements of the human eye. When the LED brightness is high, the rate of increase of the LED brightness is gradually decreased, thereby gradually increasing the LED brightness, preventing visual overshoot to the human eye and improving the user experience.

[0101] The following combination Figure 4 and Figure 5 The structure of the LED dimming circuit 400 shown introduces an LED dimming method provided by an embodiment of the present application.

[0102] Specifically, Figure 6 According to some embodiments of the present application, a flow chart of an LED dimming method is shown, and the flow chart includes the following steps.

[0103] S601: The LED dimming circuit determines the adjustment step and adjustment coefficient of N adjustment cycles according to the current brightness code and the target brightness code.

[0104] When the LED dimming circuit receives the target brightness code, it determines the adjustment step and adjustment coefficient of N adjustment cycles according to the current brightness code and the target brightness code. Figure 5As shown, the input terminal 01 of the subtractor 501 is used to receive the current brightness code, and the input terminal 02 is used to receive the target brightness code, and the adjustment range is provided to the adjustment range buffer 502. The input terminal 01 of the divider 503 is used to receive the adjustment range from the adjustment brightness buffer 502, and the input terminal 02 is used to receive the adjustment number of the LED dimming circuit. The output terminal outputs the adjustment step size, which is (Code_H-Code_0) / N in the aforementioned formula (1). The input terminal 01 of the divider 507 is used to receive the adjustment range from the output terminal of the adjustment range buffer 502, and the input terminal 02 is used to receive the quotient of the brightness code value range divided by the preset coefficient, which is (F_CODE / B) in formula (2). The output terminal is used to connect to the adjustment coefficient buffer 508 to output the quotient of the adjustment range divided by the above quotient value, that is, the adjustment coefficient A, to the adjustment coefficient buffer 508. That is, A=(Code_H-Code_0)×B / F_CODE in the aforementioned formula (2) is obtained.

[0105] It is understood that in some embodiments, the user can preset the total time T for each adjustment, and the number of adjustments N = T / T0, where T0 represents the period of the clock signal provided by the timing control circuit 401. For example, assuming that the user presets the total time for each adjustment to be 600 ms and the period of the clock signal is 10 ms, then N = 600 / 10 = 60.

[0106] S602: The LED dimming circuit determines the instruction brightness code corresponding to the nth adjustment cycle.

[0107] When n is less than or equal to N, the LED dimming circuit sets the command brightness code CODE_IN(n) of the nth adjustment cycle to the sum of the command brightness code CODE_IN(n-1) of the n-1th adjustment cycle and the adjustment step size.

[0108] like Figure 5 As shown, the input terminal 01 of the divider 503 is used to receive the adjustment range from the brightness adjustment buffer 502, and the input terminal 02 is used to receive the adjustment number of the LED dimming circuit. The output terminal is connected to the input terminal 02 of the adder 504, and the quotient of the input terminal 01 of the divider 503 divided by the input terminal 02 is output to the input terminal 02 of the adder 504. The quotient is the adjustment step size. In other words, the divider 503 is used to implement (Code_H-Code_0) / N in the above formula (1).

[0109] The input end 01 of the adder 504 is used to receive the instruction brightness code of the n-1th cycle from the instruction brightness code cache 505, and the input end 02 is used to receive the adjustment step size from the output end of the divider 503. The output end is connected to the instruction brightness code cache 505, and provides the instruction brightness code cache 505 with the sum of the instruction brightness code CODE_IN(n-1) of the n-1th adjustment cycle and the adjustment step size in the next clock cycle, that is, the instruction brightness code CODE_IN(n) of the nth adjustment cycle.

[0110] It can be understood that when n is greater than N, that is, during the N+1th adjustment cycle to the N+Mth adjustment cycle, the command brightness code CODE_IN(n) is the same as the command brightness code CODE_IN(N) of the Nth adjustment cycle.

[0111] S603: The LED dimming circuit determines the adjustment brightness code of the nth adjustment cycle according to the command brightness code of the nth adjustment cycle, the adjustment brightness code of the (n-1)th adjustment cycle, and the adjustment coefficient.

[0112] The LED dimming circuit determines the adjustment brightness code of the nth adjustment cycle according to the command brightness code of the nth adjustment cycle, the adjustment brightness code of the (n-1)th adjustment cycle, and the adjustment coefficient.

[0113] like Figure 5 As shown, the input end 01 of the subtractor 506 is used to receive the adjustment brightness code of the n-1th adjustment cycle, the input end 02 is used to receive the instruction brightness code of the nth cycle from the instruction brightness code cache 505, and the output end is used to connect the input end 01 of the divider 509.

[0114] The input terminal 01 of the divider 507 is used to receive the adjustment range from the output terminal of the adjustment range buffer 502, and the input terminal 02 is used to receive the quotient of the brightness code value range divided by the preset coefficient, that is, (F_CODE / B) in formula (2). The output terminal is connected to the adjustment coefficient buffer 508 to output the quotient of the adjustment range divided by the above quotient, that is, the adjustment coefficient A, to the adjustment coefficient buffer 508, that is, to realize A = (Code_H - Code_0) × B / F_CODE in the above formula (2).

[0115] The input end of the adjustment coefficient buffer 508 is used to receive and store the adjustment coefficient A from the output end of the divider 507 , and the output end is used to connect to the input end O2 of the divider 509 to provide the adjustment coefficient A to the input end O2 of the divider 509 .

[0116] The input end 01 of the divider 509 is used to receive the value of (CODE_IN(n)-CODE(n-1)) in formula (1) from the output end of the subtractor 506, the input end 02 is used to receive the adjustment coefficient A from the output end of the adjustment coefficient cache 508, and the output end is used to connect to the input end 02 of the adder 510, and provide the quotient of the difference between the instruction brightness code and the current brightness code divided by the adjustment coefficient to the input end 02 of the adder 510, that is, (CODE_IN(n)-CODE(n-1)) / A in formula (1). The quotient value is the adjustment brightness code of the nth adjustment cycle, which is the increment of the adjustment brightness code of the n-1th adjustment cycle, that is, CODE(n)-CODE(n-1).

[0117] The input end 01 of the adder 510 is used to receive the adjustment brightness code of the n-1th adjustment cycle, and the input end 02 is used to receive the adjustment brightness code of the n-1th adjustment cycle, which is the increment CODE(n)-CODE(n-1) compared with the adjustment brightness code of the n-1th adjustment cycle; the output end is connected to the adjustment brightness code cache 511, and is used to provide the adjustment brightness code cache 511 with the sum of the adjustment brightness code of the n-1th adjustment cycle and the increment input by the divider 509, that is, the adjustment brightness code of the n-1th adjustment cycle.

[0118] The input end of the adjustment brightness code buffer 511 is used to receive and store the adjustment brightness code of the nth adjustment cycle from the output end of the adder 510, and the output end is used to connect to the digital-to-analog conversion module 404 to provide the nth adjustment cycle adjustment brightness code, i.e., CODE(n) in formula (1), to the digital-to-analog conversion module 404.

[0119] S604: The LED dimming circuit adjusts the brightness of the LED according to the brightness adjustment code.

[0120] The LED dimming circuit adjusts the brightness of the LED according to the brightness adjustment code of the current cycle.

[0121] like Figure 5 As shown, the LED dimming circuit digital-to-analog conversion module 404 is used to receive the adjustment brightness code CODE(n) of the nth adjustment cycle output by the adjustment brightness code generation circuit 403, and output the current or voltage corresponding to the adjustment brightness code CODE(n) to the LED to adjust the brightness of the LED to the brightness corresponding to the adjustment brightness code CODE(n).

[0122] It is understandable that the process of adjusting the LED brightness in each adjustment cycle can be achieved by repeating the aforementioned steps S602 to S604, which will not be described in detail here.

[0123] It can be understood that in some embodiments, if the target brightness code input to the input terminal 02 of the subtractor 501 changes during the process of adjusting the brightness of the LED from the initial brightness to the target brightness, the output terminal of the subtractor 501 will obtain a new adjustment range, and the subtractor 501 will input the new adjustment range into the adjustment range cache 502, thereby repeating the above steps S601 to S604 to perform new adjustments.

[0124] It can be understood that in some embodiments, after completing the Nth adjustment, if the target brightness code received by the input end 02 of the subtractor 501 has not changed, the instruction brightness code is kept unchanged, and the above steps S603 and S604 are repeated to perform LED dimming.

[0125] Based on the above-described LED dimming circuit 500, since the rate of increase of the brightness code is gradually increased and then gradually decreased, the voltage or current output to the LED by the digital-to-analog conversion module 404 also gradually increases and then gradually decreases. Therefore, when adjusting the brightness of the LED from the initial brightness to the target brightness, when the LED brightness is low, the rate of increase of the LED brightness is gradually increased, thereby slowly increasing the LED brightness and meeting the adaptation requirements of the human eye. When the LED brightness is high, the rate of increase of the LED brightness is gradually decreased, thereby gradually increasing the LED brightness, preventing visual overshoot to the human eye and improving the user experience.

[0126] It is understood that in some embodiments, the aforementioned steps S601 to S604 may also be implemented by an electronic device through a processor executing instructions, rather than through an LED dimming circuit, and this is not limited here.

[0127] further Figure 7 This figure shows the curves of linear dimming, exponential dimming, and the dimming of the present invention when adjusting the brightness code from 0 to 2048 according to some embodiments of the present invention. The exponential dimming coefficient is 1.002, and the exponential dimming formula is Y = 2048 × (1.002^CODE_IN) / 60; the linear dimming coefficient is 1024. The horizontal axis represents the number of adjustments, and the vertical axis represents the brightness code output corresponding to each adjustment.

[0128] like Figure 7 As shown, for linear dimming, the adjustment brightness code is linearly related to the number of adjustments, that is, the adjustment brightness code (i.e., LED brightness) increases linearly with the increase in the number of adjustments, and the growth rate of the adjustment brightness code (i.e., the growth rate of LED brightness) remains unchanged. However, at low brightness, linear dimming has the problem of uneven brightness growth, which cannot meet the adaptation needs of the human eye.

[0129] With exponential dimming, the brightness code is exponentially related to the number of adjustments. This means the brightness code (and therefore the LED brightness) increases exponentially with the number of adjustments, and the rate at which the brightness code increases (and therefore the rate at which the LED brightness increases) also increases exponentially. When the brightness code is high, the LED brightness increases too quickly, causing a significant impact on the human eye.

[0130] For the dimming of this application, the growth rate of the adjustment brightness code (that is, the growth rate of the LED brightness) first gradually increases and then gradually decreases as the number of adjustments increases. Therefore, when the adjustment brightness code is small, the growth rate of the LED brightness gradually increases, which is better for the human eye experience; when the adjustment brightness code is large, the growth rate of the LED brightness gradually slows down, reducing the visual impact of the human eye.

[0131] further, Figure 8 A schematic diagram shows the curves for linear dimming, exponential dimming, and the dimming of the present application when adjusting the brightness of an LED from the corresponding brightness code from 0 to 512. The exponential dimming coefficient is 1.00304, and the exponential dimming formula is Y = 2048 × (1.004^CODE_IN) / 500; the linear dimming coefficient is 256. The horizontal axis represents the number of adjustments, and the vertical axis represents the brightness code output corresponding to each adjustment.

[0132] like Figure 8 As shown, for linear dimming, the adjustment brightness code is linearly related to the number of adjustments, that is, the adjustment brightness code (that is, LED brightness) increases linearly with the increase of the number of adjustments, and the adjustment brightness code growth rate (that is, the LED brightness growth rate) remains unchanged. However, at low brightness, linear dimming has the problem of non-smooth brightness growth, which cannot meet the adaptation needs of the human eye; for exponential dimming, the dimming curve only has a part of the complete exponential dimming curve, which causes the LED brightness to change only within a small range, affecting the user experience; for the dimming of this application, the adjustment brightness code growth rate (that is, the LED brightness growth rate) first gradually increases and then gradually decreases with the increase of the number of adjustments. Therefore, when the adjustment brightness code is small, the LED brightness growth rate gradually increases, which is better for the human eye experience. When the adjustment brightness code is large, the LED brightness growth rate gradually slows down, reducing the visual impact of the human eye.

[0133] In summary, the LED dimming circuit of this application has a simple structure and uncomplicated logic. Furthermore, in the LED dimming curve of this application, the LED brightness growth rate first gradually increases and then gradually decreases as the adjustment time increases. This allows the LED brightness to gradually increase at low brightness levels, avoiding sudden changes in the LED brightness. When the LED brightness approaches the target brightness, the LED brightness growth rate gradually decreases, preventing overshoot to the human eye and improving the user experience.

[0134] An embodiment of the present application further provides an electronic device, which includes an LED and the aforementioned LED dimming circuit 400 or dimming circuit 500 .

[0135] The various embodiments of the mechanisms disclosed in this application can be implemented in hardware, software, firmware, or a combination of these implementation methods. The embodiments of the present application can be implemented as a computer program or program code executed on a programmable system, which includes at least one processor, a storage system (including volatile and non-volatile memory and / or storage elements), at least one input device, and at least one output device.

[0136] Program code can be applied to input instructions to perform the functions described herein and generate output information. The output information can be applied to one or more output devices in a known manner. For purposes of this application, a processing system includes any system having a processor such as, for example, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), or a microprocessor.

[0137] Program code can be implemented with a high-level programming language or an object-oriented programming language to communicate with the processing system. Where necessary, program code can also be implemented in assembly language or machine language. In fact, the mechanism described in this application is not limited to the scope of any particular programming language. In either case, the language can be a compiled language or an interpreted language.

[0138] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored on one or more temporary or non-temporary machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. For example, the instructions may be distributed over a network or through other computer-readable media. Therefore, a machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), including but not limited to floppy disks, optical disks, optical discs, read-only memories (CD-ROMs), magneto-optical disks, read-only memories (ROMs), random access memories (RAMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), magnetic or optical cards, flash memory, or a tangible machine-readable memory for transmitting information (e.g., carrier waves, infrared signals, digital signals, etc.) using the Internet in electrical, optical, acoustic, or other forms of propagation signals. Therefore, a machine-readable medium includes any type of machine-readable medium suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

[0139] In the accompanying drawings, some structural or method features may be shown in a particular arrangement and / or order. However, it should be understood that such a particular arrangement and / or order may not be required. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. In addition, the inclusion of a structural or method feature in a particular figure does not imply that such feature is required in all embodiments, and in some embodiments, such features may not be included or may be combined with other features.

[0140] It should be noted that the units / modules mentioned in the various device embodiments of the present application are all logical units / modules. Physically, a logical unit / module can be a physical unit / module, or a part of a physical unit / module, or can be implemented as a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important. The combination of functions implemented by these logical units / modules is the key to solving the technical problems raised by this application. In addition, in order to highlight the innovative part of this application, the above-mentioned device embodiments of this application do not introduce units / modules that are not closely related to solving the technical problems raised by this application. This does not mean that other units / modules do not exist in the above-mentioned device embodiments.

[0141] It should be noted that in the examples and description of this patent, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "including a" does not exclude the presence of other identical elements in the process, method, article or device that includes the element.

[0142] Although the present application has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the application.

Claims

1. A LED dimming method, characterized in that: include: Obtaining the current brightness and a first target brightness of the LED, wherein the first target brightness is greater than the current brightness; Determining Q intermediate brightnesses between the current brightness and the first target brightness, wherein an increase rate of the Q intermediate brightnesses first increases and then decreases as Q increases; sequentially adjusting the brightness of the LED to the kth brightness among Q intermediate brightnesses, where 1≤k≤Q; The Q intermediate brightnesses are determined by the following formula: ， Among them, CODE (k) is the brightness code corresponding to the kth intermediate brightness; CODE (k-1) is the brightness code corresponding to the k-1th intermediate brightness; A is the adjustment coefficient, and A>1; Code_IN (k) = (Code_H-Code_0) × k / N + Code_0, Code_0 is the brightness code corresponding to the current brightness, and Code_H is the brightness code corresponding to the first target brightness; CODE (0) = Code_0.

2. The method according to claim 1, characterized in that The increasing speed of the first N intermediate brightnesses of the Q intermediate brightnesses increases as Q increases, and the increasing speed of the last QN intermediate brightnesses decreases as Q increases.

3. The method according to claim 1, characterized in that The adjustment coefficient A is determined by the following formula: A=(Code_H-Code_0)×B / F_CODE, Wherein, the F_CODE is the value range of brightness coding, and the B is a preset coefficient.

4. The method according to claim 1 or 3, characterized in that The step of sequentially adjusting the brightness of the LED to a kth brightness among Q intermediate brightnesses comprises: The brightness code CODE(k) corresponding to the k-th brightness among the Q intermediate brightnesses is sequentially converted into a corresponding current or voltage, and the corresponding current or voltage is input to the LED.

5. An LED dimming circuit, characterized in that: It includes a brightness code generation circuit and a digital-to-analog conversion circuit, wherein: The brightness code generating circuit is configured to generate Q intermediate brightness codes between the current brightness code and the first target brightness code when receiving the current brightness code corresponding to the current brightness of the LED and the first target brightness code, wherein an increase rate of the Q intermediate brightness codes first increases and then decreases as Q increases; The digital-to-analog conversion circuit is used to sequentially convert the kth brightness code among the Q intermediate brightness codes into a corresponding voltage or current and output it to the LED, wherein 1≤k≤Q; The brightness code generation circuit determines the Q intermediate brightness codes based on the following formula: ， Among them, CODE (k) is the kth intermediate brightness code; CODE (k-1) is the k-1th intermediate brightness code; A is the adjustment coefficient, and A>1; Code_IN (k) = (Code_H-Code_0) × k / N + Code_0, Code_0 is the current brightness code, and Code_H is the first target brightness code; CODE (0) = Code_0.

6. The circuit according to claim 5, characterized in that The increasing speed of the first N intermediate brightness codes of the Q intermediate brightness codes increases as Q increases, and the increasing speed of the last QN intermediate brightness codes decreases as Q increases.

7. The circuit according to claim 5, characterized in that The adjustment coefficient A is determined by the following formula: A=(Code_H-Code_0)×B / F_CODE, Wherein, the F_CODE is the value range of brightness coding, and the B is a preset coefficient.

8. The circuit according to claim 7, characterized in that The LED dimming circuit further includes a timing control circuit for periodically generating a clock signal; and the brightness code generation circuit generates one of the intermediate brightness codes each time it receives one of the clock signals.

9. The circuit according to claim 8, characterized in that The brightness code generation circuit includes a first brightness coding subcircuit and a second brightness coding subcircuit; The first brightness encoding sub-circuit receives the current brightness code and the first target brightness code, and upon receiving the kth clock signal, generates and outputs the Code_IN(k) to the second brightness encoding sub-circuit; The second brightness coding sub-circuit is used to generate a kth intermediate brightness code CODE(k) and output it to the digital-to-analog conversion circuit when receiving the kth clock signal.

10. The circuit according to claim 9, characterized in that The first brightness encoding subcircuit includes: a first subtractor, a first buffer, a first divider, a first adder and a second buffer; wherein, The input end of the first subtractor is used to receive the current brightness code and the first target brightness code, and the output end is connected to the input end of the first cache, the output end of the first cache is connected to an input end of the first divider, the other input end of the first divider is used to receive the Q, the output end is connected to an input end of the first adder, the other input end of the first adder is connected to the output end of the second cache, and the output end is connected to the input end of the second cache, and the output end of the second cache is used to output the Code_IN (k).

11. The circuit according to claim 10, characterized in that The second brightness encoding subcircuit includes: a second subtractor, a second divider, a third buffer, a third divider, a second adder and a fourth buffer; wherein, One input end of the second subtractor is connected to the output end of the second cache, the other input end is connected to the output end of the fourth cache, and the output end is connected to one input end of the third divider. One input end of the second divider is connected to the output end of the first cache, the other input end is used to receive the quotient of the F_CODE divided by the B, and the output end is connected to the input end of the third cache. The output end of the third cache is connected to the other input end of the third divider. The output end of the third divider is connected to one input end of the second adder. The other input end of the second adder is connected to the output end of the fourth cache, and the output end is connected to the output end of the fourth cache. The output end of the fourth cache is connected to the digital-to-analog conversion circuit.

12. An electronic device, characterized in that: include: LED; a memory, wherein instructions are stored in the memory; At least one processor is configured to execute the instructions to adjust the brightness of the LED by the method according to any one of claims 1 to 4.

13. An electronic device, characterized in that: The LED dimming circuit comprises the LED dimming circuit according to any one of claims 5 to 11.

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