Driving circuit and display device

Abstract

The invention relates to a driving circuit and a display device. The driving circuit is configured to obtain a pulse width parameter; the pulse width parameter is determined based on the target backlight brightness; under the condition that the pulse width parameter is greater than a first parameter threshold value, generating a first pulse signal to drive a light-emitting chip; the first pulse signal comprises a plurality of pulses, and the first pulse signal has a first preset pulse frequency; under the condition that the pulse width parameter is smaller than a second parameter threshold value, a second pulse signal is generated to drive the light-emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold value is greater than or equal to the second parameter threshold value; the pulse number of the second pulse signal in the unit time length is smaller than the pulse number in the unit time length corresponding to the first preset pulse frequency. The backlight brightness adjusting precision can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a driving circuit and a display device. BACKGROUND

[0002] With the development of display technology, in order to realize the fine regulation of the luminance of the light-emitting chip, the pulse width modulation (PWM) dimming scheme has become the industry mainstream. PWM dimming controls the average luminance by periodically switching the current channel to adjust the on duration of the light-emitting chip per unit time (i.e. the duty cycle, PWM duty). PWM dimming has high dimming precision and wide dynamic range, and can realize linear stepless adjustment from extremely dark to extremely bright, meeting the requirements of scenes such as HDR (High Dynamic Range) display with strict contrast requirements; in addition, its digital control logic and driving circuit are highly compatible, which is convenient for integration into various display backlight control circuits, reducing system complexity and power consumption. In addition, PWM dimming has fast response speed, which can effectively eliminate the brightness trailing under dynamic picture, and improve the display fluency.

[0003] However, when PWM dimming enters an extremely dark scene, the duty cycle (PWM duty) needs to be compressed to an extremely low level, at this time the width of the current pulse has approached the physical limit, and the transient characteristics of the rising / falling edge have greatly amplified the influence weight on the current precision, resulting in low luminance regulation precision and affecting the display effect of the display device. SUMMARY

[0004] Therefore, it is necessary to provide a driving circuit and a display device capable of improving the luminance regulation precision of the light-emitting chip to solve the above technical problems.

[0005] In a first aspect, the present application provides a driving circuit, which is configured to:

[0006] obtain a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight luminance;

[0007] generate a first pulse signal to drive the light-emitting chip when the pulse width parameter is greater than a first parameter threshold; the first pulse signal comprises a plurality of pulses, and the first pulse signal has a first preset pulse frequency;

[0008] generate a second pulse signal to drive the light-emitting chip when the pulse width parameter is less than a second parameter threshold; the second pulse signal comprises a plurality of pulses with a second pulse width;

[0009] The first parameter threshold is greater than or equal to the second parameter threshold; and the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency.

[0010] Beneficial effects: The driving circuit obtains a pulse width parameter determined based on the target backlight brightness. When the pulse width parameter is greater than a first parameter threshold, the driving circuit generates a first pulse signal with multiple pulses and a first preset pulse frequency to drive the light-emitting chip to emit light. In this way, the driving circuit adjusts the light-emitting brightness of the light-emitting chip by adjusting the pulse width of the pulse when the pulse width parameter does not affect the adjustment accuracy of the backlight brightness, thereby speeding up the driving speed, making the brightness change of the light-emitting chip more balanced, and reducing local brightness fluctuation. When the pulse width parameter is less than a second parameter threshold, the pulse width parameter is too small at this time, which may cause low brightness adjustment accuracy and affect the backlight adjustment effect. In the embodiment, the second pulse signal with the number of pulses in a unit time less than the number of pulses in a unit time corresponding to the first preset pulse frequency is generated to drive the light-emitting chip to emit light, so as to avoid continuously adjusting the pulse width of the pulse signal, causing the pulse width to be too small, introducing an increase in edge time proportion, effectively stabilizing the current, reducing the brightness adjustment accuracy, and achieving precise adjustment of the light-emitting height of the light-emitting chip.

[0011] In a second aspect, the present application provides a display device, comprising:

[0012] a display panel configured to display an image;

[0013] an image processing chip configured to output a pulse width parameter corresponding to a target backlight brightness, wherein the target backlight brightness corresponds to the image;

[0014] a backlight module configured to provide a light source for the display panel, wherein the backlight module comprises:

[0015] a light-emitting chip;

[0016] a driving circuit according to the first aspect, wherein the driving circuit is connected to the light-emitting chip and the image processing chip, and configured to drive the light-emitting chip to emit light.

[0017] Beneficial effects: Because the drive circuit can obtain the pulse width parameter determined based on the target backlight brightness, in the case where the pulse width parameter is greater than the first parameter threshold, a first pulse signal with multiple pulses and a first preset pulse frequency is generated to drive the light emitting chip to emit light, so that the drive circuit adjusts the light emitting brightness of the light emitting chip by adjusting the pulse width of the pulse in the case where the pulse width parameter does not affect the adjustment accuracy of the backlight brightness, speeds up the driving speed, makes the brightness change of the light emitting chip more balanced, and reduces local brightness fluctuation. In the case where the pulse width parameter is less than the second parameter threshold, at this time, the pulse width parameter is too small, which easily causes low brightness adjustment accuracy and affects the backlight adjustment effect. In the embodiment, the second pulse signal with the number of pulses in a unit time less than the number of pulses in a unit time corresponding to the first preset pulse frequency is generated to drive the light emitting chip to emit light, avoiding the continuous adjustment of the pulse width of the pulse signal, causing the pulse width to be too small, introducing the increase of the edge time ratio, effectively stabilizing the current reduction, and affecting the brightness adjustment accuracy. The problem is solved, and accurate adjustment of the light emitting height of the light emitting chip is realized. Therefore, the display effect of the display device in the embodiment can also be correspondingly improved.

[0018] In a third aspect, the present application provides a display device, comprising:

[0019] a display panel configured to display an image;

[0020] a backlight module configured to provide a light source for the display panel, the backlight module comprising:

[0021] a light emitting chip;

[0022] a backlight control circuit connected to the light emitting chip and configured to output a pulse signal, wherein the pulse signal is configured to drive the light emitting chip to emit light, and the backlight control circuit is configured to:

[0023] generate a first pulse signal to drive the light emitting chip in a case where a target backlight brightness is greater than a first brightness threshold, wherein the first pulse signal comprises a plurality of pulses with a first pulse width, and the first pulse signal has a first preset pulse frequency;

[0024] generate a second pulse signal to drive the light emitting chip in a case where the target backlight brightness is less than a second brightness threshold, wherein the second pulse signal comprises a plurality of pulses with a second pulse width;

[0025] wherein the first brightness threshold is greater than or equal to the second brightness threshold, the first pulse width is greater than the second pulse width of the second pulse signal, and the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency.

[0026] Beneficial effects: in the case of target backlight brightness greater than the first brightness threshold, the first pulse signal with multiple pulses and the first preset pulse frequency is generated to drive the light emitting chip to emit light, so that the driving circuit adjusts the light emitting brightness of the light emitting chip by adjusting the pulse width of the pulse under the condition that the pulse width parameter corresponding to the target backlight brightness does not affect the adjustment accuracy of the backlight brightness, speeds up the driving speed, makes the brightness change of the light emitting chip more balanced, and reduces the local brightness fluctuation. In the case of target backlight brightness less than the second brightness threshold, at this time, the pulse width parameter corresponding to the target backlight brightness is too small, which is easy to cause low brightness adjustment accuracy and affect the backlight adjustment effect. In the embodiment, the second pulse signal with the number of pulses in the unit time less than the number of pulses in the unit time corresponding to the first preset pulse frequency is generated to drive the light emitting chip to emit light, avoiding the continuous adjustment of the pulse width of the pulse signal, causing the pulse width to be too small, introducing the increase of the edge time ratio, effectively stabilizing the current reduction, and affecting the brightness adjustment accuracy. The problem is solved, and the light emitting height of the light emitting chip is accurately adjusted. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without creating labor.

[0028] Figure 1 One of the flowcharts for driving the light emitting chip by the driving circuit in an embodiment of the present application;

[0029] Figure 2 The timing diagram of the plurality of pulse signals in an embodiment of the present application;

[0030] Figure 3 One of the flowcharts for generating the second pulse signal by the driving circuit in the case of the pulse width parameter less than the second parameter threshold in an embodiment of the present application;

[0031] Figure 4 The second flowchart for generating the second pulse signal by the driving circuit in the case of the pulse width parameter less than the second parameter threshold in an embodiment of the present application;

[0032] Figure 5 The second flowchart for driving the light emitting chip by the driving circuit in an embodiment of the present application;

[0033] Figure 6 The relationship between the pulse widths corresponding to the second parameter threshold, the third parameter threshold, the fourth parameter threshold and the fifth parameter threshold in an embodiment of the present application;

[0034] Figure 7 A flowchart for generating the third pulse signal by the driving circuit in an embodiment of the present application;

[0035] Figure 8 A structural diagram of the display device in an embodiment of the present application;

[0036] Figure 9 A flowchart for controlling the light emitting chip to emit light by the backlight control circuit in an embodiment of the present application;

[0037] Figure 10 A flowchart for generating the second pulse signal by the backlight control circuit in an embodiment of the present application when the target backlight brightness is less than the second brightness threshold;

[0038] Figure 11 A flowchart for generating the second pulse signal by the backlight control circuit in an embodiment of the present application when the target backlight brightness is less than the second brightness threshold;

[0039] Figure 12 A flowchart for controlling the light emitting chip to emit light by the backlight control circuit in an embodiment of the present application;

[0040] Figure 13 A flowchart for generating the third pulse signal by the backlight control circuit in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without using these specific details in other ways. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0042] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0043] In addition, if there are these terms "first", "second", these terms are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, if the term "a plurality of" appears, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0044] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be understood in a broad sense. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0045] In the field of display technology, the essence of PWM dimming is to realize the on-off control of the light-emitting chip by high-frequency switching of the high-low level state in the current pulse signal, to control the lighting time ratio of the light-emitting chip by changing the duration of the high-low level state in a fixed frequency period (duty ratio), thereby realizing the brightness adjustment of the light-emitting chip. The longer the duration of the high level state, the greater the average current of the pulse signal, the longer the light-emitting time of the light-emitting chip, and the higher the average brightness. Conversely, the shorter the duration of the high level state, the smaller the average current of the pulse signal, the shorter the light-emitting time of the light-emitting chip, and the lower the average brightness.

[0046] In low-brightness scenarios, under PWM dimming, the duty cycle of the pulse signal needs to be reduced. When the duty cycle is already very small, the pulse signal edges have a significant impact on current accuracy. The inventors discovered that this is because, with a very small duty cycle, the duration of the high-level state is extremely short. Therefore, the time for the LED to receive effective current is extremely short, and the proportion of time for the pulse signal edges (rising and falling edges) increases significantly, directly affecting accuracy. For example, taking a pulse width of 1µs, there is a 0.2µs rising edge (rising process), followed by a 0.8µs falling edge (falling process). Due to the asymmetry between the rising and falling edges, the duration and the rising and falling processes differ, leading to errors in the average current and thus dimming errors. The shorter the pulse width, the larger the proportion of the rising and falling processes, and the greater the proportion of error caused by this asymmetry. On the other hand, the hardware response speed of the driving circuit has a limit. If the hardware does not respond in time at a low duty cycle, it will affect the stable output of the current pulse signal, causing the actual average current to deviate more from the theoretical value, which will further affect the brightness adjustment accuracy of the light-emitting chip.

[0047] Based on this, the inventors further discovered that reducing the amplitude of the pulse signal can alleviate the accuracy problem caused by an excessively small pulse signal duty cycle. Since the average current = pulse signal amplitude × pulse signal duty cycle, reducing the pulse signal amplitude and increasing the pulse signal duty cycle can keep the average value of the final output pulse signal constant, reducing edge effects and improving accuracy. However, the luminous flux generated per unit current of the light-emitting chip is not a fixed value; it varies with the current amplitude, and the variation is not proportional. Therefore, even if the average current remains constant, the actual brightness of the light-emitting chip may deviate under different amplitudes. This necessitates the introduction of an additional luminous efficacy compensation algorithm to dynamically adjust the pulse signal's duty cycle or amplitude based on the pulse signal amplitude, significantly increasing algorithm complexity and implementation difficulty. Furthermore, since the heat generated by the driving circuit mainly comes from conduction losses, which are the product of the square of the current amplitude, the internal conduction resistance of the driving circuit, and the conduction time, even if the duty cycle is increased, the decrease in the square of the current amplitude after the current amplitude is reduced is usually less than the increase in the duty cycle. This leads to an increase in total conduction losses, which in turn increases the total heat generation of the driving circuit, which is detrimental to the display performance of the display device.

[0048] Based on this, a driving circuit is provided in the embodiments of this application. See attached drawing. Figure 1 , attached Figure 1 This illustration shows one of the flowcharts illustrating how a driving circuit drives a light-emitting chip to emit light, according to an embodiment of this application. The driving circuit in this embodiment can be configured to perform steps S101 to S103.

[0049] Step S101: Obtain the pulse width parameter; wherein the pulse width parameter is determined based on the target backlight brightness.

[0050] The driving circuit can receive pulse width parameters sent by the host computer to directly obtain the pulse width parameters. Alternatively, the driving circuit can process pulse width-related information sent by the host computer to obtain the pulse width parameters. In this embodiment, the pulse width parameters can represent the pulse width desired by the host computer.

[0051] In this embodiment, brightness is divided into two dimensions—amplitude and pulse width. That is, one backlight brightness value corresponds to a set of parameter pairs (amplitude parameter and pulse width parameter, respectively). This can be understood as each brightness value corresponding to a parameter curve or a region in a pulse width-amplitude two-dimensional coordinate system. In this embodiment, the amplitude parameter can characterize the amplitude desired by the host computer.

[0052] The pulse width parameter can be a parameter that is equal to or related to the conduction time encoding when the backlight brightness is the target backlight brightness (e.g., the pulse width parameter is a natural number). Being related to the conduction time encoding means having a preset mapping relationship with it. Conduction time encoding refers to the digital encoding of the high-level duration in the pulse signal, mapping the target high-level duration value to binary or multi-level code through preset encoding rules.

[0053] Taking the pulse width parameter as an example, which is equal to the conduction time code, Ton time (the conduction time represented by the pulse width parameter) = Tclk (clock cycle, where clk is the clock signal used to generate the pulse signal) × Ton code (conduction time code, which represents how many clock cycles are needed to constitute the conduction time).

[0054] The host computer can be an intermediate conversion chip or an image processing chip, etc. For example, an intermediate conversion chip can refer to a chip that organizes and relays the image data sent by the image processing chip. The image data can refer to data related to image display, such as pulse width parameters or amplitude parameters in the embodiments of this application, etc., and is not limited thereto.

[0055] Step S102: When the pulse width parameter is greater than the first parameter threshold, a first pulse signal is generated to drive the light-emitting chip; the first pulse signal includes multiple pulses and has a first preset pulse frequency.

[0056] In the first pulse signal, the amplitude of each pulse is positively correlated with the amplitude parameter, and the pulse width of the pulse is positively correlated with the pulse width parameter.

[0057] When the pulse width parameter is greater than the first parameter threshold, it can be characterized as a display scene where the target backlight brightness is in the medium-high brightness range. In this case, the pulse generated in the first pulse signal is the same as the pulse expected by the host computer; that is, the pulse amplitude of the first pulse signal is equal to the pulse amplitude characterized by the amplitude parameter, and the pulse width of the first pulse signal is equal to the pulse width characterized by the pulse width parameter. The first parameter threshold is a parameter threshold associated with the pulse width parameter. The frequency of the first pulse signal is a first preset pulse frequency, which refers to the number of times the first pulse signal periodically repeats within a unit of time.

[0058] Step S103: When the pulse width parameter is less than the second parameter threshold, a second pulse signal is generated to drive the light-emitting chip; the second pulse signal includes multiple pulses with a second pulse width. Further, the second pulse width is a fixed value. Wherein, the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses in the second pulse signal per unit time is less than the number of pulses per unit time corresponding to the first preset pulse frequency. At this time, the pulses generated in the second pulse signal are different from the pulses expected by the host computer. Specifically, the pulse amplitude of the second pulse signal is equal to the pulse amplitude represented by the amplitude parameter, while the pulse width of the second pulse signal is not equal to the pulse width represented by the pulse width parameter. By setting the pulse width to a fixed value and reducing the number of pulses per unit time, the brightness is achieved to be the same as the brightness generated by the pulses expected by the host computer, while simultaneously improving the problem of excessively low dimming accuracy caused by further reduction in pulse width.

[0059] When the pulse width parameter is less than the second parameter threshold, it indicates a low-brightness display scenario for the target backlight. The pulse width of the second pulse signal can be a fixed value. For example, the pulse width of the second pulse signal can be fixed to the pulse width value corresponding to the second parameter threshold. The second parameter threshold can represent a preset lower limit parameter for the pulse width, thereby reducing the loss of brightness adjustment accuracy caused by an excessively small pulse width.

[0060] The number of pulses in the second pulse signal within a unit time period is less than the number of pulses within a unit time period corresponding to the first preset pulse frequency. For example, if the first preset pulse frequency of the first pulse signal is such that the number of times the periodic pulse repeats within a unit time period T1 is 5, then the number of pulses in the second pulse signal within a unit time period T1 is less than 5.

[0061] Alternatively, it can be understood that when the pulse width parameter is less than the threshold of the second parameter, the pulse width of the second pulse signal is a fixed value, and the number of pulses of the second pulse signal within a unit time T1 is less than the number of pulses of the pulse signal within a unit time T1 whose actual pulse width and pulse amplitude are equal to the pulse width represented by the pulse width parameter and the pulse amplitude represented by the amplitude parameter under the corresponding backlight brightness.

[0062] In the embodiments of this application, when the pulse width parameter is greater than the first parameter threshold, the pulse width of the first pulse signal output by the driving circuit corresponds only to the pulse width parameter obtained by the driving circuit. For example, the driving circuit obtains the pulse width parameter directly or indirectly from the host computer, and the driving circuit generates a first pulse signal with a corresponding pulse width based on the pulse width parameter.

[0063] When the pulse width parameter is less than the second parameter threshold, the pulse width of the second pulse signal output by the driving circuit is no longer set according to the acquired pulse width parameter. At this time, the pulse width of the second pulse signal output by the driving circuit is a fixed value. Instead of reducing the backlight brightness by reducing the pulse width of the pulse signal, the display requirements for low backlight brightness are met by reducing the number of pulses of the pulse signal per unit time.

[0064] The first and second parameter thresholds can be equal, or the first parameter threshold can be greater than the second parameter threshold. For example, the first parameter threshold can be 34 and the second parameter threshold can be 33. It is not limited to this, as long as the first and second parameter thresholds can be used to define the medium-high brightness scene and the low brightness scene.

[0065] The unit duration can be a time period. For example, the unit duration can be understood as a preset duration. Alternatively, the unit duration can be understood as a period that includes multiple clock cycles or multiple first pulse signals.

[0066] In some embodiments, the operating frequency of the frame synchronization pulse signal and the pulse signal in this invention are different. The frame synchronization pulse signal corresponds to the actual frame frequency, such as 120Hz. The frame frequency is the number of times the display panel refreshes the image per second, used to control the update speed of the image content. For example, a frame frequency of 120Hz means that the display panel can present 120 independent frames per second, thereby ensuring the smoothness of dynamic image display. The pulse signal in this invention is used to drive the light-emitting chip, controlling the single light-emitting duration of the light-emitting chip by alternating high and low levels, thereby achieving precise adjustment of display brightness. The operating frequency of the pulse signal in this invention is much higher than the frequency of the frame synchronization pulse signal, for example, it can be 120kHz. The pulse frequency of the pulse signal in this invention is defined as the number of times the pulse signal repeats per unit time. Within the complete display cycle of a single frame, the pulse signal can complete multiple frequency switching, that is, multiple sets of pulse drive signals of different frequencies can be output during the display of a single frame. Through high-frequency adjustment of the light-emitting duration, fine control of brightness within a single frame is achieved.

[0067] For example, see Appendix Figure 2 , attached Figure 2 Figures a and b in the diagram are timing diagrams of the second pulse signal in traditional PWM dimming. Figure 2Figures c and d in the diagram are timing diagrams of the second pulse signal in the embodiments of this application. Taking the on-time of PWM1 in figure a as O1, the on-time of PWM2 in figure b as O2, the on-time of PWM3 in figure c as O3, and the on-time of PWM4 in figure d as O4 as an example, where O1=O3=O4=2×O2, the amplitude current is A, the PWM period of PWM1 is T1, the average current of PWM1 is O1×A / T1, the average current of PWM2 is O2×A / T1=O1×A / T1 / 2, the average current of PWM3 is O3×A / (2×T1)=O1×A / T1 / 2, and the average current of PWM4 is 5×O4×A / (10×T1)=O1×A / T1 / 2. PWM2 describes traditional PWM dimming, which reduces brightness (average current) by decreasing the pulse width (compared to PWM1). PWM3 and PWM4 reduce brightness (average current) by fixing the pulse width and decreasing the number of pulses per unit time. PWM3 and PWM4 indicate that after the on-time decreases to a certain value, brightness is no longer reduced by decreasing the on-time of a single pulse. Instead, brightness is reduced by fixing the on-time (i.e., pulse width) within a certain time range and decreasing the number of pulses per unit time. This avoids the loss of brightness accuracy caused by excessively short on-time of a single pulse.

[0068] It is understood that steps S101 to S103 in the embodiments of this application can be executed according to the numerical judgment result of the pulse width parameter, and it is not required that steps S101 to S103 must occur in sequence.

[0069] In this embodiment, the driving circuit acquires a pulse width parameter determined based on the target backlight brightness. When the pulse width parameter is greater than a first parameter threshold, it generates a first pulse signal with multiple pulses and a first preset pulse frequency to drive the light-emitting chip to emit light. This allows the driving circuit to adjust the brightness of the light-emitting chip by adjusting the pulse width without affecting the backlight brightness adjustment accuracy, thus accelerating the driving speed and making the brightness change of the light-emitting chip more uniform, reducing local brightness fluctuations. When the pulse width parameter is less than a second parameter threshold, the pulse width parameter is too small, which can easily lead to low brightness adjustment accuracy and affect the backlight adjustment effect. In this embodiment, by generating a second pulse signal with a pulse number within a unit time period less than the pulse number within a unit time period corresponding to the first preset pulse frequency, the light-emitting chip is driven to emit light. This avoids the problem of the pulse width being too small due to further adjustment of the pulse signal, which would introduce an increased edge time ratio, reduce the effective stabilizing current, and affect the brightness adjustment accuracy. This achieves precise adjustment of the light-emitting height of the light-emitting chip.

[0070] In some embodiments, the second pulse signal is generated uniformly, that is, the spacing between any two adjacent pulses in the second pulse signal is equal, such as... Figure 2 As shown in PWM3, the second pulse signal is generated in the following way.

[0071] See appendix Figure 3 , attached Figure 3 One schematic diagram illustrates how a driving circuit generates a second pulse signal when the pulse width parameter is less than a second parameter threshold. In this embodiment, generating the second pulse signal when the pulse width parameter is less than the second parameter threshold may include the following steps: Figure 3 The steps S301 to S303 are illustrated in (a) of the figure.

[0072] Step S301: When the pulse width parameter is less than the second parameter threshold, a new cumulative value is generated every preset time interval based on the current pulse width parameter and the current cumulative value; wherein, the preset time interval is equal to the period of the first pulse signal. Optionally, a rising edge of a detection pulse is generated every preset time interval, and a new cumulative value is generated before each rising edge arrives based on the pulse width parameter and the current cumulative value.

[0073] Understandably, in the first preset duration, the current cumulative value can be the preset initial value, and the first new cumulative value can refer to the cumulative value generated by the pulse width parameter and the preset initial value. The new cumulative value in the current preset duration becomes the current cumulative value in the next preset duration.

[0074] For example, in the first preset duration, the preset initial value is Tinit, and the pulse width parameter is Ton code. When the pulse width parameter Ton code is less than the second parameter threshold Tth2, the driving circuit generates a first new cumulative value Tc1 every preset duration based on the current pulse width parameter Ton code and the preset initial value Tinit. In the second preset duration, when the pulse width parameter Ton code is less than the second parameter threshold Tth2, a second new cumulative value Tc2 is generated every preset duration based on the current pulse width parameter Ton code and the first new cumulative value Tc1 (i.e., the current cumulative value).

[0075] For example, the new cumulative value can be the sum of the pulse width parameter and the current cumulative value. For instance, in the first preset duration, Tc1 = Tinit + Ton code; in the second preset duration, Tc2 = Tc1 + Ton code.

[0076] Step S302: If the new accumulated value is greater than or equal to the second parameter threshold, output a pulse with a second pulse width and decrease the new accumulated value. In this embodiment, decreasing the new accumulated value is configured to make the accumulated value become the new accumulated value minus the second parameter threshold; this invention does not limit this.

[0077] For example, the new cumulative value can be reduced by subtracting the new cumulative value from the second parameter threshold. For instance, if the first new cumulative value Tc1 is greater than or equal to the second parameter threshold Tth2, a pulse of the second pulse width is output, and the first new cumulative value is reduced, so that the first new cumulative value Tc1 becomes: Tc1-Tth2.

[0078] In step S303, if the new cumulative value is less than the second parameter threshold, no pulse is output.

[0079] For example, see Appendix Figure 3 In Figure (b), when the pulse width parameter is less than the second parameter threshold, the second pulse width of the second pulse signal is a fixed value. The backlight brightness is adjusted by reducing the number of pulses of the second pulse signal per unit time. In the first preset time, the preset current cumulative value is the initial value Tinit, and the first new cumulative value Tc1 = Tinit + the current pulse width parameter Ton code. If Tc(0) = Tinit, then Tc1 = Tc(0) + the current pulse width parameter Ton code. In subsequent preset time periods, every preset time period, before the rising edge of the detection pulse signal arrives, a new cumulative value Tc(m) = Tc(m-1) + the current pulse width parameter Ton code is calculated, where m ≥ 2 and is an integer. Thus, every preset time period, a cumulative value Tc(m) = Tc(m-1) + the current pulse width parameter Ton code is generated, where m ≥ 1 and is an integer. When Tc(m) is greater than or equal to Tth2, a pulse with the second pulse width is output, and Tc(m) is reduced. Optionally, in this embodiment, Tc(m) = Tc(m) - Tth2. No pulse is output when Tc(m) is less than Tth2.

[0080] It is understood that steps S301 to S303 in the embodiments of this application can be executed according to the judgment result of the pulse width parameter value and the judgment result of the new cumulative value, and are not limited to the sequential occurrence of steps S301 to S303.

[0081] In this embodiment, when the pulse width parameter is less than the second parameter threshold, a new cumulative value is generated every preset time interval based on the current pulse width parameter and the current cumulative value; wherein, the preset time interval is equal to the period of the first pulse signal. If the new cumulative value is greater than or equal to the second parameter threshold, a pulse with the second pulse width is output, and the new cumulative value is reduced; otherwise, no pulse is output. The output of the pulse can be controlled in real time according to the relationship between the cumulative value and the second parameter threshold, so that the number of pulses of the second pulse signal within a unit time interval is limited by the second parameter threshold, thereby reducing the number of pulses of the second pulse signal within a unit time interval and thus achieving the purpose of reducing the backlight brightness. With the average current remaining constant, the loss of brightness adjustment accuracy caused by an excessively small duty cycle of the second pulse signal is avoided, improving the accuracy of brightness adjustment of the light-emitting chip. While judging the relationship between the cumulative value and the second parameter threshold, the output of a second pulse signal with a fixed pulse width is simultaneously adjusted to adjust the number of pulses of the second pulse signal. With the average current remaining constant, the loss of brightness adjustment accuracy caused by an excessively small duty cycle of the second pulse signal is reduced, improving the accuracy of brightness adjustment of the light-emitting chip.

[0082] In some embodiments, the pulses of the second pulse signal are not generated uniformly, such as... Figure 2 As shown in PWM4, pulses are generated for the first 5 preset durations and no pulses are generated for the last 5 preset durations. This invention does not limit this; any scheme that generates the number of pulses corresponding to the pulse parameters within a unit duration is within the scope of protection of this invention. For example, no pulses may be generated for the first 5 preset durations, and pulses may be generated for the last 5 preset durations, or pulses may be generated for any 5 preset durations out of 10 preset durations. In this case, the second pulse signal is generated in the following manner.

[0083] See appendix Figure 4 , attached Figure 4 The second schematic diagram illustrates the process of generating a second pulse signal by a driving circuit when the pulse width parameter is less than the second parameter threshold. In this embodiment, generating the second pulse signal when the pulse width parameter is less than the second parameter threshold may include the following steps S401 to S403.

[0084] Step S401: If the pulse width parameter is less than the second parameter threshold, the number of pulses represented by the pulse width parameter is taken as the number of pulses of the second pulse signal within a unit time.

[0085] Step S402: Obtain the value of the second pulse width based on the second parameter threshold.

[0086] The value of the second pulse width can have a preset correspondence with the second parameter threshold. For example, the second parameter threshold can have a preset ratio with the value of the second pulse width, such as the second pulse width Ton time = Tclk × Toncode, where Tclk can refer to the clock period of the clock signal used to generate the first pulse signal.

[0087] Step S403: Output a second pulse signal with a second pulse width and a second number of pulses within a unit time period.

[0088] In this embodiment, the driving circuit can pre-determine the number of pulses of the second pulse signal within a unit time when the pulse width parameter is less than the second parameter threshold. The number of pulses represented by the pulse width parameter is used as the number of pulses of the second pulse signal within a unit time, eliminating the need for calculations before each rising edge, reducing the output time of the second pulse signal, and improving adjustment efficiency. The value of the second pulse width is obtained based on the second parameter threshold, ensuring that the average current of the second pulse signal meets the condition corresponding to the target backlight brightness. The backlight brightness is adjusted only by reducing the number of pulses within a unit time.

[0089] In some embodiments, the unit duration is equal to N preset durations, and the period of the first pulse signal is equal to the preset duration. When the pulse width parameter is less than the second parameter threshold, generating the second pulse signal may include: within each unit duration, outputting pulses with the second pulse width for each of the n preset durations, and not outputting pulses for any of the (Nn) preset durations.

[0090] Where N equals the second parameter threshold and n equals the pulse width parameter.

[0091] For example, when determining the number of pulses and the second pulse width of the second pulse signal within a unit time period, within each unit time period, as shown in the appendix... Figure 2 In the d-graph, pulses with the second pulse width can be output for n preset durations, and no pulses can be output for (Nn) preset durations.

[0092] In another example, given that the number of pulses and the second pulse width of the second pulse signal are determined within a unit time, within each unit time, no pulses may be output for (Nn) preset time periods, and then pulses with the second pulse width may be output for n preset time periods respectively.

[0093] As another example, given that the number of pulses and the second pulse width of the second pulse signal are determined within a unit time period, pulses with the second pulse width can be output for n preset time periods in the middle part of each unit time period, while no pulses are output for the other (Nn) preset time periods. This is not the only possible explanation.

[0094] In this embodiment, the unit duration is equal to N preset durations, and the period of the first pulse signal is equal to the preset duration. When the pulse width parameter is less than the second parameter threshold, within each unit duration, pulses with the second pulse width are output for each of the n preset durations, and no pulses are output for any of the (Nn) preset durations. N equals the second parameter threshold, and n equals the pulse width parameter, thus realizing the output of the second pulse signal. This ensures that the second pulse signal has the second pulse width and the number of pulses within the unit duration, so as to achieve the adjustment of the backlight brightness by reducing the number of pulses of the second pulse signal and fixing the second pulse width while satisfying the target backlight brightness.

[0095] In some embodiments, see Appendix Figure 5 , attached Figure 5 The second schematic diagram of the process of driving the light-emitting chip to emit light by the driving circuit in one embodiment of this application is shown. The driving circuit in this embodiment of the application can be configured to perform the following steps S501 to S502.

[0096] Step S501: Obtain amplitude parameters; amplitude parameters are determined based on the target backlight brightness;

[0097] The amplitude parameter can refer to the parameter obtained directly from the host computer by the driving circuit to control the amplitude of the third pulse signal. Alternatively, the amplitude parameter can be a parameter generated by the driving circuit based on the amplitude signal related to the amplitude of the third pulse signal output by the host computer, used to characterize the host computer's amplitude requirement for the third pulse signal.

[0098] In step S502, when the pulse width parameter is less than the third parameter threshold, a third pulse signal is generated to drive the light-emitting chip; the third pulse signal includes multiple pulses with a third pulse width.

[0099] In this system, the pulse amplitude of the third pulse signal is less than the pulse amplitude represented by the amplitude parameter. The number of pulses in the third pulse signal per unit time is a fixed value. The width of the third pulse is equal to the width of the second pulse, and the threshold value of the third parameter is less than the threshold value of the second parameter. At this point, the pulses generated in the third pulse signal differ from the pulses expected by the host computer. Specifically, the pulse amplitude of the third pulse signal is not equal to the pulse amplitude represented by the amplitude parameter, and the pulse width of the second pulse signal is not equal to the pulse width represented by the pulse width parameter. By setting the pulse width to a fixed value, the number of pulses no longer decreases (i.e., it is fixed), and the pulse amplitude represented by the amplitude parameter is reduced to obtain the pulse amplitude of the third pulse signal, thus achieving the same brightness as the pulses expected by the host computer. This also improves the problem of excessively low dimming accuracy caused by further reduction in pulse width.

[0100] For example, in step S502 of this embodiment, the pulse parameter is smaller than the pulse parameter corresponding to step S103. After reducing the number of pulses of the second pulse signal per unit time in step S103, if the pulse parameter is further reduced, the backlight brightness can be adjusted by controlling the pulse amplitude of the third pulse signal to be lower than the pulse amplitude corresponding to the current pulse width parameter. In this embodiment, as the pulse parameter continuously decreases, the backlight brightness is adjusted by first adjusting the number of pulses and then adjusting the amplitude.

[0101] In one embodiment, when the pulse width parameter is less than the third parameter threshold, it can be indicated that the number of pulses of the second pulse signal within a unit time has reached the preset threshold. If the number of pulses of the pulse signal within a unit time is further reduced, it may cause flickering and affect the display effect. In order to further respond to the low brightness display requirements, the amplitude corresponding to the amplitude parameter can be reduced to obtain the actual pulse amplitude. That is, a third pulse signal is generated with a pulse amplitude less than that represented by the corresponding amplitude parameter, a third fixed value for the number of pulses within a unit time, and a pulse width equal to the second pulse width. This improves the flickering problem, enhances the stability of brightness adjustment, and ensures the display effect.

[0102] In the above description, as the pulse width parameter continuously decreases, the process involves: 1) reducing the number of pulses per unit duration; and 2) reducing the amplitude corresponding to the current amplitude parameter to obtain the actual pulse amplitude, thereby generating the corresponding pulse signal. This invention does not limit this process. In another embodiment, as the pulse width parameter continuously decreases, the above processes (i.e., processes 1 and 2) can be repeated N times, where N is greater than 1 (e.g., when N=2, the sequence is: process 1, process 2, process 1, process 2).

[0103] Specifically, the driving circuit can be configured to: generate a fourth pulse signal to drive the light-emitting chip when the pulse width parameter is less than the fourth parameter threshold; the number of pulses of the fourth pulse signal per unit time is less than the number of pulses of the third pulse signal per unit time; generate a fifth pulse signal to drive the light-emitting chip when the pulse width parameter is less than the fifth parameter threshold; the fifth pulse amplitude of the fifth pulse signal is less than the pulse amplitude represented by the corresponding amplitude parameter, and the number of pulses of the fifth pulse signal per unit time is a fifth fixed value.

[0104] Among them, the threshold of the fourth parameter is less than the threshold of the third parameter, and the threshold of the fifth parameter is less than the threshold of the fourth parameter.

[0105] For example, see Appendix Figure 6 , attached Figure 6 A schematic diagram illustrating the relationship between pulse parameters and the actual pulse width is shown in one embodiment of this application. (The attached diagram is not included in the provided text.) Figure 6(a) shows the case where, after the pulse parameter is less than the second parameter threshold, the actual pulse widths are all equal, and the actual pulse width is the second pulse width (i.e., a fixed value). Brightness adjustment is achieved by adjusting the number of pulses and / or the amplitude of the pulse signal per unit time. (Appendix) Figure 6 (b) shows the case where the actual pulse width is different when the pulse parameter is lower than the second parameter threshold and when it is lower than the fourth parameter threshold. The actual pulse width when the pulse parameter is lower than the second parameter threshold is the second fixed value, and the actual pulse width corresponding to the pulse parameter being lower than the fourth parameter threshold is the third fixed value. When the second fixed value is greater than the third fixed value, that is, the actual pulse width decreases once for each repetition of process 1 and process 2.

[0106] In this embodiment, the fourth parameter threshold is less than the third parameter threshold, and the fifth parameter threshold is less than the fourth parameter threshold. When the pulse width parameter is less than the fourth parameter threshold, a fourth pulse signal is generated with a pulse count less than the third pulse signal within a unit duration. When the pulse width parameter is less than the fifth parameter threshold, a fifth pulse signal is generated with a pulse amplitude less than the pulse amplitude represented by the amplitude parameter and a pulse count of a fixed value within a unit duration. This achieves backlight brightness adjustment by alternately adjusting the pulse count and amplitude of the pulse signal within a unit duration, gradually reducing the pulse count and amplitude of the pulse signal within a unit duration, and improving the stability of brightness adjustment.

[0107] In some embodiments, see Appendix Figure 7 , attached Figure 7 A schematic diagram of the process for generating the third pulse signal by the driving circuit is shown. In this embodiment, the generation of the third pulse signal by the driving circuit may include the following steps S701 to S703.

[0108] Step S701: Obtain the ratio of the pulse width parameter to the third parameter threshold.

[0109] For example, the third parameter threshold can be 2. i Since i is an integer, the divisor of the third parameter threshold is a power of 2. The driving circuit determines the third amplitude of the third pulse signal based on the ratio of the pulse width parameter to the third parameter threshold and the amplitude parameter. The number of pulses output within a unit time duration is taken as the third parameter threshold and the third pulse signal with the third pulse width and third pulse amplitude. This can be calculated simply through shifting and addition, reducing the data processing complexity of the backlight control circuit. Furthermore, the third pulse width is equal to the second pulse width.

[0110] Step S702: Determine the amplitude of the third pulse signal based on the ratio and amplitude parameters.

[0111] Step S703: Generate a third pulse signal based on the third pulse amplitude, the number of pulses of the third pulse signal within a unit time duration, and the third pulse width; the number of pulses of the third pulse signal within a unit time duration is equal to the third parameter threshold.

[0112] The third pulse amplitude can be a ratio to the pulse amplitude represented by the amplitude parameter, which can be the ratio of the pulse width parameter to the third parameter threshold. For example, the third pulse amplitude = the pulse amplitude represented by the amplitude parameter × the pulse width parameter Ton code / Tth3, where Tth3 is the third parameter threshold.

[0113] In this embodiment, the amplitude of the third pulse is determined based on the ratio of the pulse width parameter to the third parameter threshold and the amplitude parameter, which solves the problem of adjusting the light sensitivity under low brightness adjustment. The third pulse signal is generated based on the third pulse amplitude, the number of pulses of the third pulse signal within a unit time, and the third pulse width. The number of pulses of the third pulse signal within a unit time is equal to the third parameter threshold. The amplitude is adjusted only within a small effective range, without affecting the luminous efficiency of the light-emitting chip, reducing the computational power of additional compensation, and having no significant impact on the heat generation of the backlight control circuit.

[0114] In some embodiments, this application provides a display device, which may include a display panel, an image processing chip, and a backlight module. The display panel can be used to display images. The image processing chip is used to output pulse width parameters corresponding to a target backlight brightness; the target backlight brightness corresponds to the image; the backlight module is used to provide a light source for the display panel.

[0115] The backlight module may include a light-emitting chip and a driving circuit as described in any of the above embodiments. The driving circuit is connected to the light-emitting chip and the image processing chip, and can be used to drive the light-emitting chip to emit light.

[0116] The display device provided in this application embodiment may be a mobile terminal, computer, monitor, advertising screen, wearable device, virtual reality device, augmented reality device, etc., and is not limited thereto.

[0117] The display panel 110 in this embodiment can be used to display images. The display panel 110 converts light signals into image signals. By controlling the light transmission / blocking state of the pixel units, the light source provided by the backlight module 120 can be converted into a visual image with color and grayscale differences. The display panel 110 can be a transmissive display panel 110, capable of modulating the light transmittance, but it does not emit light itself. The display panel 110 has multiple pixel units arranged in an array. Each pixel unit can independently control the transmittance and color of the light incident from the backlight module 120 onto that pixel unit, so that the light transmitted through all pixel units constitutes the displayed image.

[0118] For example, the display panel 110 can be a liquid crystal display panel. For instance, the display panel 110 may include a liquid crystal (LC) layer and a color filter (CF) layer. The liquid crystal layer may be composed of liquid crystal molecules placed between two conductive glass plates. An electric field is applied by two electrodes, causing the liquid crystal molecules to twist, thereby adjusting the transmittance of the light emitted from the backlight to display an image. The color filter layer is located above the liquid crystal layer. The color filter layer can filter the white light emitted from the backlight to allow light of a specific wavelength (i.e., color) to pass through, thereby displaying a color image.

[0119] It should be noted that, Figure 8 The display panel 110 shown is merely an example; the display panel 110 may also have other structures. For example, the display panel 110 may not include a filter layer. The structure of the display panel 110 is not specifically limited in the embodiments of this application.

[0120] The shape and size of the display panel 110 are generally adapted to the shape and size of the display device. For example, when applied to fields such as televisions or mobile terminals, the display panel 110 can be configured as a rectangle, including a top side, a ground side, a left side, and a right side, wherein the top side and the ground side are opposite to each other, the left side and the right side are opposite to each other, the top side is connected to one end of the left side and one end of the right side, and the ground side is connected to the other end of the left side and the other end of the right side.

[0121] The backlight module 120 in this embodiment can be used to provide a light source for the display panel 110.

[0122] For example, the display panel 110 may be disposed on the light-emitting side of the backlight module 120. In this embodiment, the backlight module 120 may include a light-emitting chip 121 and a driving circuit 122. The driving circuit 122 is connected to the light-emitting chip 121 and can be used to output pulse signals. The driving circuit 122 can be used to drive the light-emitting chip 121 to emit light.

[0123] The driving circuit 122 can be connected to a power supply to convert the input DC power supply into a stable current, and adjust the brightness of the light-emitting chip 121 by controlling the magnitude of the current (average current).

[0124] The pulse signal can be understood as a pulse width modulation signal (PWM signal). By controlling the conduction time ratio of the light-emitting chip 121 through high-frequency switching current, the brightness can be adjusted to ensure stable light emission of the light-emitting chip 121, so that the human eye does not feel flicker when viewing the display panel 110.

[0125] The driving circuit 122 can receive dimming commands or dimming data (such as pulse width parameters and / or amplitude parameters) from external sources (such as a host computer), or output pulse signals through duty cycle parameters preset in the internal register. The pulse width and / or amplitude parameters of the output pulse signal conform to the instructions of the host computer and conform to the target backlight brightness.

[0126] The drive circuit 122 can internally house a power switch transistor, which is turned on or off under the control of a PWM signal. When the power switch transistor is on, current flows through the light-emitting chip 121, causing it to emit light. When the power switch transistor is off, the current received by the light-emitting chip 121 is insufficient to illuminate it, therefore the chip does not emit light. The pulse frequency of the PWM signal is lower than the persistence of vision frequency of the human eye; therefore, the human eye perceives the average brightness of the light-emitting chip 121. As long as the duty cycle of the PWM signal meets preset conditions, the flickering of the display panel 110 will not be perceived.

[0127] The duty cycle (on-time / cycle) of the pulse signal directly determines the average brightness of the light-emitting chip 121. For example, with a 100% duty cycle, the current is continuously on, and the light-emitting chip 121 can emit light at its maximum current, achieving maximum brightness. With a 50% duty cycle, the light-emitting chip 121 emits light for half the time and is off for the other half, resulting in an average brightness of 50% of its maximum brightness. With a 10% duty cycle, the average brightness of the light-emitting chip 121 is 10% of its maximum brightness (suitable for low-brightness scenarios).

[0128] In this embodiment, since the driving circuit 122 can obtain the pulse width parameter determined based on the target backlight brightness, when the pulse width parameter is greater than the first parameter threshold, it generates a first pulse signal with multiple pulses and a first preset pulse frequency to drive the light-emitting chip 121 to emit light. This allows the driving circuit 122 to adjust the brightness of the light-emitting chip 121 by adjusting the pulse width of the pulses without affecting the backlight brightness adjustment accuracy, thereby accelerating the driving speed and making the brightness change of the light-emitting chip 121 more balanced, reducing local brightness fluctuations. When the pulse width parameter is less than the second parameter threshold, the pulse width parameter is too small, which can easily lead to low brightness adjustment accuracy and affect the backlight adjustment effect. In this embodiment, by generating a second pulse signal with a pulse number within a unit time period less than the pulse number within a unit time period corresponding to the first preset pulse frequency to drive the light-emitting chip 121 to emit light, it avoids the problem of the pulse width being too small due to continued adjustment of the pulse signal, which would introduce an increased edge time ratio, reduce the effective stabilizing current, and affect the brightness adjustment accuracy. This achieves precise adjustment of the light-emitting height of the light-emitting chip 121. Therefore, it can also improve the display effect of the display device in this embodiment.

[0129] In one embodiment, this application also provides a display device, which may include a display panel and a backlight module, wherein the backlight module provides a light source for the display panel.

[0130] A backlight module may include a light-emitting chip and a backlight control circuit. The backlight control circuit is connected to the light-emitting chip and can be used to output pulse signals. The backlight control circuit can be used to drive the light-emitting chip to emit light.

[0131] The backlight control circuit can be connected to a power supply to convert the input DC power into a stable current, and adjust the brightness of the light-emitting chip by controlling the magnitude of the current (average current).

[0132] The pulse signal can be understood as a pulse width modulation signal (PWM signal). By controlling the conduction time ratio of the light-emitting chip through high-frequency switching current, the brightness can be adjusted, ensuring stable light emission of the light-emitting chip and making the human eye feel no flicker when viewing the display panel.

[0133] The backlight control circuit can receive dimming commands or dimming data (such as pulse width parameters and / or amplitude parameters) from external sources (such as a host computer), or output pulse signals through the duty cycle parameters preset in the internal register. The pulse width and / or amplitude parameters of the output pulse signal conform to the instructions of the host computer and meet the target backlight brightness.

[0134] For example, the backlight control circuit may include an image processing chip and a driving circuit connected to the image processing chip. The driving circuit may have a power switch transistor that is turned on or off under the control of a PWM signal. When the power switch transistor is on, current flows through the light-emitting chip, and the light-emitting chip emits light. When the power switch transistor is off, the current received by the light-emitting chip is insufficient to illuminate it, so the light-emitting chip does not emit light. The pulse frequency of the PWM signal is lower than the persistence of vision of the human eye, so the human eye perceives the average brightness of the light-emitting chip. When the duty cycle of the PWM signal meets the preset conditions, the flickering of the display panel will not be perceived.

[0135] The duty cycle (on-time / cycle) of the pulse signal directly determines the average brightness of the LED. For example, with a 100% duty cycle, the current is continuously flowing, and the LED can emit light at its maximum current, achieving maximum brightness. With a 50% duty cycle, the LED emits light for half the time and is off for the other half, resulting in an average brightness of 50% of its maximum. With a 10% duty cycle, the average brightness of the LED is 10% of its maximum (suitable for low-brightness scenarios).

[0136] For example, the pulse signal may include a first pulse signal and a second pulse signal. The backlight control circuit may output the first pulse signal and the second pulse signal respectively under different display brightness scenarios, but is not limited thereto.

[0137] For example, see Appendix Figure 9 , attached Figure 9 This illustration shows one of the flowcharts illustrating how a backlight control circuit controls a light-emitting chip to emit light, according to an embodiment of this application. The backlight control circuit in this embodiment can be configured to perform steps S901 to S902.

[0138] Step S901: When the target backlight brightness is greater than the first brightness threshold, a first pulse signal is generated to drive the light-emitting chip; the first pulse signal includes multiple pulses with a first pulse width and has a first preset pulse frequency.

[0139] When the target backlight brightness is greater than the first brightness threshold, it can be characterized as a medium-to-high brightness display scenario. The first brightness threshold can be set based on the brightness value corresponding to the medium-to-high brightness scenario.

[0140] For example, when the target backlight brightness is greater than a first brightness threshold, the backlight control circuit can adjust the first pulse width of the first pulse signal according to the target backlight brightness. For instance, when the target backlight brightness is greater than the first brightness threshold and is decreasing, the first pulse width of the first pulse signal can be reduced to decrease the backlight brightness.

[0141] In step S902, when the target backlight brightness is less than the second brightness threshold, a second pulse signal is generated to drive the light-emitting chip; the second pulse signal includes multiple pulses with a second pulse width.

[0142] Wherein, the first brightness threshold is greater than or equal to the second brightness threshold; the first pulse width is greater than the second pulse width of the second pulse signal; and the number of pulses of the second pulse signal within a unit time is less than the number of pulses within a unit time corresponding to the first preset pulse frequency.

[0143] When the target backlight brightness is less than the second brightness threshold, it can be characterized as a low-brightness display scenario. The pulse width of the second pulse signal can be a fixed value. For example, the pulse width of the second pulse signal can be fixed to the value of the pulse width corresponding to the second brightness threshold. The second brightness threshold can characterize the brightness value corresponding to the lower limit parameter of the pulse width of the second pulse signal, thereby reducing the loss of brightness adjustment accuracy caused by the pulse width of the second pulse signal being too small.

[0144] The number of pulses in the second pulse signal within a unit time period is less than the number of pulses within a unit time period corresponding to the first preset pulse frequency. For example, if the first preset pulse frequency of the first pulse signal is such that the number of times the periodic pulse repeats within a unit time period T1 is 5, then the number of pulses in the second pulse signal within a unit time period T1 is less than 5.

[0145] Alternatively, it can be understood that when the target backlight brightness is less than the second brightness threshold, the pulse width of the second pulse signal is a fixed value, and the number of pulses of the second pulse signal within a unit time T1 is less than the number of pulses of the pulse signal within a unit time T1 when the actual pulse width and pulse amplitude are equal to the pulse width represented by the pulse width parameter and the pulse amplitude represented by the amplitude parameter under the corresponding backlight brightness.

[0146] It is understood that steps S901 to S902 in the embodiments of this application may be executed according to the judgment result of the target backlight brightness, and are not limited to the sequential occurrence of steps S901 to S902.

[0147] In this embodiment, when the target backlight brightness is greater than a first brightness threshold, the pulse width of the first pulse signal output by the backlight control circuit corresponds only to the pulse width parameter generated based on the target backlight brightness. For example, the backlight control circuit directly or indirectly obtains the pulse width parameter from the host computer, and generates a first pulse signal with the corresponding pulse width based on the pulse width parameter.

[0148] When the target backlight brightness is less than the second brightness threshold, the second pulse signal output by the backlight control circuit is no longer set solely based on the pulse width parameter. Instead, the pulse width of the second pulse signal output by the backlight control circuit is a fixed value. Instead of reducing the pulse width to decrease backlight brightness, the circuit reduces the number of pulses per unit time to meet the low backlight brightness display requirements.

[0149] The first brightness threshold and the second brightness threshold can be equal, or the first brightness threshold can be greater than the second brightness threshold; it is not limited to these two types. The only requirement is that the first and second brightness thresholds can be used to define medium-high brightness scenes and low brightness scenes.

[0150] In this embodiment, when the target backlight brightness is greater than a first brightness threshold, a first pulse signal with multiple pulses and a first preset pulse frequency is generated to drive the light-emitting chip to emit light. This allows the driving circuit to adjust the brightness of the light-emitting chip by adjusting the pulse width of the pulses, without affecting the backlight brightness adjustment accuracy, thus accelerating the driving speed and making the brightness change of the light-emitting chip more balanced, reducing local brightness fluctuations. When the target backlight brightness is less than a second brightness threshold, the pulse width parameter corresponding to the target backlight brightness is too small, which can easily lead to low brightness adjustment accuracy and affect the backlight adjustment effect. In this embodiment, by generating a second pulse signal with fewer pulses per unit time than the number of pulses per unit time corresponding to the first preset pulse frequency to drive the light-emitting chip to emit light, the problem of excessively small pulse width caused by further adjustment of the pulse signal is avoided. This would lead to an increased edge time ratio, a reduced effective stabilizing current, and an impact on brightness adjustment accuracy, thus achieving precise adjustment of the light-emitting height of the light-emitting chip.

[0151] In some embodiments, see Appendix Figure 10 , attached Figure 10 This illustration shows one of the flowcharts illustrating how a backlight control circuit generates a second pulse signal when the target backlight brightness is less than a second brightness threshold, according to an embodiment of this application. In this embodiment, generating the second pulse signal when the target backlight brightness is less than the second brightness threshold may include the following steps S1001 to S1004.

[0152] Step S1001: If the target backlight brightness is less than the second brightness threshold, determine the pulse width parameter corresponding to the target backlight brightness that is less than the second brightness threshold.

[0153] Step S1002: At each preset time interval, a new cumulative value is generated based on the pulse width parameter and the current cumulative value; wherein, the preset time interval is equal to the period of the first pulse signal.

[0154] It is understandable that in the first preset duration, the current cumulative value can be the preset initial value, and the first new cumulative value can refer to the cumulative value generated by the pulse width parameter and the preset initial value.

[0155] For example, in the first preset duration, the preset initial value is Tinit, and the pulse width parameter is Ton code. When the pulse width parameter Ton code is less than the second parameter threshold Tth2, the driving circuit generates a first new cumulative value Tc1 every preset duration based on the current pulse width parameter Ton code and the preset initial value Tinit. In the second preset duration, when the pulse width parameter Ton code is less than the second parameter threshold Tth2, a second new cumulative value Tc2 is generated every preset duration based on the current pulse width parameter Ton code and the first new cumulative value Tc1 (i.e., the current cumulative value).

[0156] For example, the new cumulative value can be the sum of the pulse width parameter and the current cumulative value. For instance, in the first preset duration, Tc1 = Tinit + Ton code; in the second preset duration, Tc2 = Tc1 + Ton code.

[0157] Step S1003: If the new cumulative value is greater than or equal to the preset second parameter threshold, output a pulse with a second pulse width and decrease the new cumulative value; the second parameter threshold corresponds to the pulse width parameter corresponding to the second brightness threshold.

[0158] For example, the new cumulative value can be reduced by subtracting the new cumulative value from the second parameter threshold. For instance, if the first new cumulative value Tc1 is greater than or equal to the second parameter threshold Tth2, a pulse of the second pulse width is output, and the first new cumulative value is reduced, so that the first new cumulative value becomes: Tc1-Tth2.

[0159] In step S1004, if the new cumulative value is less than the second parameter threshold, no pulse is output.

[0160] For example, see Appendix Figure 3In Figure (b), when the target backlight brightness is less than the second brightness threshold, the pulse width parameter corresponding to the target backlight brightness is less than the preset second parameter threshold. The second pulse width of the second pulse signal is a fixed value. The backlight brightness is adjusted by reducing the number of pulses of the second pulse signal per unit time. In the first preset time, the preset current cumulative value is the initial value Tinit, and the first new cumulative value Tc1 = Tinit + pulse width parameter Toncode. In subsequent preset time periods, every preset time period, before the rising edge of the second pulse signal arrives, a new cumulative value Tc(m) = Tc(m-1) + the current Ton code is calculated, where m ≥ 2 and is an integer. When Tc1 or Tc(m) is greater than or equal to Tth2, a pulse with the second pulse width is output, and Tc1 or Tc(m) is decreased. When Tc1 or Tc(m) is less than Tth2, no pulse is output.

[0161] It is understood that steps S1001 to S1004 in this embodiment can be executed based on the judgment result of the target backlight brightness and the judgment result of the new cumulative value, and are not limited to occurring in a specific order. In this embodiment, when the target backlight brightness is less than the second brightness threshold, the pulse width parameter corresponding to the target backlight brightness less than the second brightness threshold is determined. At preset intervals, a new cumulative value is generated based on the pulse width parameter and the current cumulative value; wherein the preset interval is equal to the period of the first pulse signal. If the new cumulative value is greater than or equal to the second parameter threshold, a pulse with the second pulse width is output, and the new cumulative value is reduced; otherwise, no pulse is output. The pulse output can be controlled in real time based on the relationship between the cumulative value and the second parameter threshold, so that the number of pulses of the second pulse signal within a unit time is limited by the second parameter threshold, thereby reducing the number of pulses of the second pulse signal within a unit time and achieving the purpose of reducing the backlight brightness. With the average current unchanged, the loss of brightness adjustment accuracy caused by the excessively small duty cycle of the second pulse signal is avoided, improving the accuracy of brightness adjustment of the light-emitting chip. While judging the relationship between the cumulative value and the second parameter threshold, the system simultaneously adjusts whether to output a second pulse signal with a fixed pulse width, thereby adjusting the number of pulses in the second pulse signal. This avoids the loss of brightness adjustment accuracy caused by the duty cycle of the second pulse signal being too small, while keeping the average current constant, thus improving the accuracy of brightness adjustment of the light-emitting chip.

[0162] In some embodiments, the pulses of the second pulse signal are not generated uniformly, such as... Figure 2As shown in PWM4, pulses are generated for the first 5 preset durations and no pulses are generated for the last 5 preset durations. This invention does not limit this; any scheme that generates the number of pulses corresponding to the pulse parameters within a unit duration is within the scope of protection of this invention. For example, no pulses may be generated for the first 5 preset durations, and pulses may be generated for the last 5 preset durations, or pulses may be generated for any 5 preset durations out of 10 preset durations. In this case, the second pulse signal is generated in the following manner.

[0163] See appendix Figure 11 , attached Figure 11 This illustration shows a second schematic diagram of the backlight control circuit generating a second pulse signal when the target backlight brightness is less than a second brightness threshold, according to one embodiment of this application. In this embodiment, generating the second pulse signal when the target backlight brightness is less than the second brightness threshold may include the following steps S1101 to S1102.

[0164] Step S1101: When the target backlight brightness is less than the second brightness threshold, the number of pulses represented by the pulse width parameter corresponding to the target backlight brightness is taken as the number of pulses of the second pulse signal within a unit time.

[0165] Step S1102: Output a second pulse signal with a second pulse width and a second number of pulses within a unit time period.

[0166] The value of the second pulse width can have a preset correspondence with the second parameter threshold. For example, the second parameter threshold can have a preset ratio with the value of the second pulse width, such as the second pulse width Ton time = Tclk × Toncode, where Tclk can refer to the clock period of the clock signal used to generate the second pulse signal.

[0167] In this embodiment, the backlight control circuit can pre-determine the number of pulses of the second pulse signal within a unit time when the target backlight brightness is less than the second brightness threshold. The preset second parameter threshold, corresponding to the pulse width parameter of the second brightness threshold, is used as the number of pulses of the second pulse signal within a unit time. This eliminates the need for calculations before each rising edge, reducing the output time of the second pulse signal and improving adjustment efficiency. The value of the second pulse width is obtained based on the second parameter threshold, ensuring that the average current of the second pulse signal meets the condition corresponding to the target backlight brightness. The backlight brightness is adjusted simply by reducing the number of pulses within a unit time.

[0168] In some embodiments, the unit duration is equal to N preset durations, and the period of the first pulse signal is equal to the preset duration; outputting a second pulse signal with a second pulse width and a number of pulses within the unit duration includes: outputting pulses with a second pulse width for each of the n preset durations within each unit duration, and not outputting pulses for any of the (Nn) preset durations.

[0169] Where N equals the preset second parameter threshold, and n equals the pulse width parameter corresponding to the target backlight brightness.

[0170] For example, when determining the number of pulses and the second pulse width of the second pulse signal within a unit time period, within each unit time period, as shown in the appendix... Figure 2 In the d-graph, pulses with the second pulse width can be output for n preset durations, and no pulses can be output for (Nn) preset durations.

[0171] In another example, given that the number of pulses and the second pulse width of the second pulse signal are determined within a unit time, within each unit time, no pulses may be output for (Nn) preset time periods, and then pulses with the second pulse width may be output for n preset time periods respectively.

[0172] As another example, given that the number of pulses and the second pulse width of the second pulse signal are determined within a unit time period, pulses with the second pulse width can be output for n preset time periods in the middle part of each unit time period, while no pulses are output for the other (Nn) preset time periods. This is not the only possible explanation.

[0173] In this embodiment, the unit duration is equal to N preset durations, and the period of the first pulse signal is equal to the preset duration. When the target backlight brightness is less than the second brightness threshold, within each unit duration, pulses with the second pulse width are output for each of the n preset durations, and no pulses are output for any of the (Nn) preset durations. N equals the second parameter threshold, and n equals the pulse width parameter, thus realizing the output of the second pulse signal. This ensures that the second pulse signal has the second pulse width and the number of pulses within the unit duration, so as to achieve the adjustment of the backlight brightness by reducing the number of pulses of the second pulse signal and fixing the second pulse width while satisfying the target backlight brightness.

[0174] In some embodiments, see Appendix Figure 12 , attached Figure 12 This is a second schematic diagram illustrating the process of a backlight control circuit controlling a light-emitting chip to emit light, according to one embodiment of this application. The backlight control circuit in this embodiment can be configured to perform the following step S1201.

[0175] Step S1201: When the target backlight brightness is less than the third brightness threshold, determine the amplitude parameter corresponding to the target backlight brightness, determine the third pulse amplitude based on the amplitude parameter, and generate a third pulse signal based on the third pulse amplitude to drive the light-emitting chip.

[0176] The amplitude parameter can be a parameter obtained directly from the host computer by the backlight control circuit to control the amplitude of the third pulse signal. Alternatively, the amplitude parameter can be a parameter generated by the backlight control circuit based on the amplitude signal related to the amplitude of the third pulse signal output by the host computer, used to characterize the host computer's amplitude requirement for the third pulse signal.

[0177] The amplitude of the third pulse is less than the pulse amplitude represented by the amplitude parameter. The number of pulses of the third pulse signal within a unit time is a third fixed value. The width of the third pulse is equal to the width of the second pulse.

[0178] In this system, the pulse amplitude of the third pulse signal is less than the pulse amplitude represented by the amplitude parameter. The number of pulses in the third pulse signal per unit time is a fixed value. The width of the third pulse is equal to the width of the second pulse, and the threshold value of the third parameter is less than the threshold value of the second parameter. At this point, the pulses generated in the third pulse signal differ from the pulses expected by the host computer. Specifically, the pulse amplitude of the third pulse signal is not equal to the pulse amplitude represented by the amplitude parameter, and the pulse width of the second pulse signal is not equal to the pulse width represented by the pulse width parameter. By setting the pulse width to a fixed value, the number of pulses no longer decreases (i.e., it is fixed), and the pulse amplitude represented by the amplitude parameter is reduced to obtain the pulse amplitude of the third pulse signal, thus achieving the same brightness as the pulses expected by the host computer. This also improves the problem of excessively low dimming accuracy caused by further reduction in pulse width.

[0179] For example, the pulse parameter in this embodiment is smaller than the pulse parameter corresponding to step S902. After reducing the number of pulses of the second pulse signal per unit time in step S902, if the pulse parameter is further reduced, the backlight brightness can be adjusted by controlling the pulse amplitude of the third pulse signal to be lower than the pulse amplitude corresponding to the current pulse width parameter. In this embodiment, as the pulse parameter continuously decreases, the backlight brightness is adjusted by first adjusting the number of pulses and then adjusting the amplitude.

[0180] In one embodiment, when the target backlight brightness is less than a third brightness threshold, it indicates that the number of pulses in the second pulse signal within a unit time has reached a preset threshold. Further reducing the number of pulses within a unit time may lead to flickering, affecting the display effect. To better respond to low-brightness display requirements, an amplitude parameter corresponding to the target backlight brightness can be determined, and a third pulse amplitude can be determined based on this parameter. A third pulse signal is then generated based on this third pulse amplitude to drive the light-emitting chip. By reducing the amplitude corresponding to the amplitude parameter to obtain the actual pulse amplitude—that is, generating a third pulse signal with a pulse amplitude less than the amplitude parameter, a third fixed number of pulses within a unit time, and a pulse width equal to the second pulse width—flickering is improved, the stability of brightness adjustment is enhanced, and the display effect is ensured.

[0181] In the above description, as the pulse width parameter continuously decreases, the process involves: 1) reducing the number of pulses per unit duration; and 2) reducing the amplitude corresponding to the current amplitude parameter to obtain the actual pulse amplitude, thereby generating the corresponding pulse signal. This invention does not limit this process. In another embodiment, as the pulse width parameter continuously decreases, the above processes (i.e., processes 1 and 2) can be repeated N times, where N is greater than 1 (e.g., when N=2, the sequence is: process 1, process 2, process 1, process 2).

[0182] In some embodiments, the backlight control circuit can be configured to generate a fourth pulse signal to drive the light-emitting chip when the target backlight brightness is less than a fourth brightness threshold; the number of pulses of the fourth pulse signal per unit time is less than the number of pulses of the third pulse signal per unit time.

[0183] When the target backlight brightness is less than the fifth brightness threshold, a fifth pulse signal is generated to drive the light-emitting chip; the fifth pulse amplitude of the fifth pulse signal is less than the pulse amplitude represented by the corresponding amplitude parameter, and the number of pulses of the fifth pulse signal per unit time is a fifth fixed value.

[0184] Among them, the fourth brightness threshold can be less than the third brightness threshold, and the fifth brightness threshold can be less than the fourth brightness threshold.

[0185] In this embodiment, when the target backlight brightness is less than the fourth brightness threshold, a fourth pulse signal is generated, in which the number of pulses per unit time is less than the number of pulses per unit time of the third pulse signal. When the target backlight brightness is less than the fifth brightness threshold, a fifth pulse signal is generated, in which the amplitude of the fifth pulse is less than the pulse amplitude represented by the amplitude parameter, and the number of pulses per unit time is a fifth fixed value. This achieves backlight brightness adjustment by alternately adjusting the number of pulses and the amplitude of the pulse signal per unit time, gradually reducing the number of pulses and the amplitude of the pulse signal per unit time, and improving the stability of brightness adjustment.

[0186] In some embodiments, see Appendix Figure 13 , attached Figure 13 The diagram illustrates a flow chart of a backlight control circuit generating a third pulse signal according to an embodiment of this application. In this embodiment, the backlight control circuit generating the third pulse signal may include steps S1301 to S1303.

[0187] Step S1301: Obtain the ratio of the pulse width parameter to the third parameter threshold; the pulse width parameter corresponds to the target backlight brightness that is less than the third brightness threshold; the third parameter threshold corresponds to the third brightness threshold.

[0188] For example, the third parameter threshold can be 2. i Since i is an integer, the divisor of the third parameter threshold is a power of 2. The driving circuit determines the third amplitude of the third pulse signal based on the ratio of the pulse width parameter to the third parameter threshold and the amplitude parameter. The number of pulses output within a unit time is the third parameter threshold and the third pulse signal with the third pulse width and the third pulse amplitude. The algorithm is simple and can reduce the data processing difficulty of the backlight control circuit by shifting calculations.

[0189] Step S1302: Determine the amplitude of the third pulse signal based on the ratio and amplitude parameters.

[0190] Step S1303: Generate a third pulse signal based on the third pulse amplitude, the number of pulses of the third pulse signal within a unit time duration, and the third pulse width; the number of pulses of the third pulse signal within a unit time duration is equal to the third parameter threshold.

[0191] The third pulse amplitude can be a ratio to the pulse amplitude represented by the amplitude parameter, which can be the ratio of the pulse width parameter to the third parameter threshold. For example, the third pulse amplitude = the pulse amplitude represented by the amplitude parameter × the pulse width parameter Ton code / Tth3, where Tth3 is the third parameter threshold.

[0192] In this embodiment, the amplitude of the third pulse is determined based on the ratio of the pulse width parameter to the third parameter threshold and the amplitude parameter, which can solve the problem of adjusting the light sensitivity under low brightness adjustment. The third pulse signal is generated based on the third pulse amplitude, the number of pulses of the third pulse signal within a unit time, and the third pulse width. The number of pulses of the third pulse signal within a unit time is equal to the third parameter threshold. The amplitude is adjusted only within a small effective range, which does not affect the luminous efficiency of the light-emitting chip, reduces the computing power of additional compensation, and has no significant impact on the heat generation of the backlight control circuit.

[0193] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0194] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0195] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A drive circuit characterized by comprising: The driving circuit is configured to: acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is greater than a first parameter threshold, generate a first pulse signal to drive the light emitting chip; the first pulse signal comprises a plurality of pulses, and the first pulse signal has a first preset pulse frequency; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency.

2. The drive circuit according to claim 1, characterized in that, The driving circuit is configured to: acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency.

3. The drive circuit according to claim 1, characterized by The driving circuit is configured to: acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency.

4. The drive circuit according to claim 1, characterized by The driving circuit is configured to: acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency.

5. The drive circuit according to any one of claims 1 to 4, characterized by The driving circuit is configured to: acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency. The driving circuit is configured to:

6. The drive circuit according to claim 5, characterized in that, acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency. The driving circuit is configured to: acquire a pulse width parameter; wherein the pulse width parameter is determined based on a target backlight brightness; in a case where the pulse width parameter is less than a second parameter threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first parameter threshold is greater than or equal to the second parameter threshold; the number of pulses of the second pulse signal in a unit time is less than the number of pulses in a unit time corresponding to the first preset pulse frequency. The fourth pulse signal has a number of pulses in a unit time period that is less than a number of pulses of the third pulse signal in the unit time period; In a case where the pulse width parameter is less than a fifth parameter threshold, a fifth pulse signal is generated to drive the light emitting chip; A fifth pulse amplitude of the fifth pulse signal is less than a pulse amplitude represented by a corresponding amplitude parameter, and the fifth pulse signal has a fifth fixed value of pulses in the unit time period; The fourth parameter threshold is less than the third parameter threshold, and the fifth parameter threshold is less than the fourth parameter threshold.

7. The drive circuit according to claim 5, characterized by The third pulse signal is generated by: obtaining a ratio of the pulse width parameter to a third parameter threshold; determining a third pulse amplitude of the third pulse signal according to the ratio and the amplitude parameter; generating the third pulse signal according to the third pulse amplitude, a number of pulses of the third pulse signal in the unit time period, and the third pulse width; the number of pulses of the third pulse signal in the unit time period is equal to the third parameter threshold.

8. A display device, characterized by The display device comprises: a display panel configured to display an image; an image processing chip configured to output a pulse width parameter corresponding to a target backlight brightness; the target backlight brightness corresponds to the image; a backlight module configured to provide a light source for the display panel, the backlight module comprising: a light emitting chip; a driving circuit according to any one of claims 1 to 7, the driving circuit being connected to the light emitting chip and the image processing chip, and configured to drive the light emitting chip to emit light.

9. A display device, characterized by The display device comprises: a display panel configured to display an image; a backlight module configured to provide a light source for the display panel, the backlight module comprising: a light emitting chip; a backlight control circuit connected to the light emitting chip, and configured to output a pulse signal; the pulse signal is used to drive the light emitting chip to emit light; the backlight control circuit is configured to: in a case where a target backlight brightness is greater than a first brightness threshold, generate a first pulse signal to drive the light emitting chip; the first pulse signal comprises a plurality of pulses with a first pulse width, and the first pulse signal has a first preset pulse frequency; in a case where the target backlight brightness is less than a second brightness threshold, generate a second pulse signal to drive the light emitting chip; the second pulse signal comprises a plurality of pulses with a second pulse width; wherein the first brightness threshold is greater than or equal to the second brightness threshold; the first pulse width is greater than the second pulse width, and a number of pulses of the second pulse signal in a unit time period is less than a number of pulses in a unit time period corresponding to the first preset pulse frequency.

10. The display device of claim 9, wherein, The generation of the second pulse signal in the case where the target backlight brightness is less than the second brightness threshold comprises: in the case where the target backlight brightness is less than the second brightness threshold, determining a pulse width parameter corresponding to the target backlight brightness that is less than the second brightness threshold; every interval of a preset time period, generating a new cumulative value according to the pulse width parameter and a current cumulative value; wherein the preset time period is equal to a period of the first pulse signal. In a case where the new accumulated value is greater than or equal to a preset second parameter threshold, a pulse with the second pulse width is output, and the new accumulated value is reduced; the second parameter threshold corresponds to a pulse width parameter corresponding to the second brightness threshold; In a case where the new accumulated value is less than the second parameter threshold, the pulse is not output.

11. The display device of claim 9, wherein, The generating, in a case where the target backlight brightness is less than a second brightness threshold, of a second pulse signal includes: In a case where the target backlight brightness is less than a second brightness threshold, a pulse number represented by a pulse width parameter corresponding to the target backlight brightness is taken as a pulse number of a second pulse signal in a unit time length; The unit time length is equal to N preset time lengths, and a period of the first pulse signal is equal to the preset time length.

12. The display device of claim 11, wherein, The outputting, in the unit time length, of the second pulse signal with the second pulse width and the pulse number includes: In each unit time length, a pulse with the second pulse width is output in n preset time lengths, and the pulse is not output in (N-n) preset time lengths; N is equal to a preset second parameter threshold, and n is equal to a pulse width parameter corresponding to the target backlight brightness. The backlight control circuit is configured to:

13. The display device according to any one of claims 10 to 12, wherein, In a case where the target backlight brightness is less than a third brightness threshold, determine an amplitude parameter corresponding to the target backlight brightness, determine a third pulse amplitude based on the amplitude parameter, and generate a third pulse signal according to the third pulse amplitude to drive the light-emitting chip; The third pulse amplitude is less than a pulse amplitude represented by the amplitude parameter, a pulse number of the third pulse signal in the unit time length is a third fixed value, a third pulse width of the third pulse signal is equal to the second pulse width, and the third brightness threshold is less than the second brightness threshold. The backlight control circuit is configured to:

14. The display device of claim 13, wherein, In a case where the target backlight brightness is less than a fourth brightness threshold, generate a fourth pulse signal to drive the light-emitting chip; a pulse number of the fourth pulse signal in a unit time length is less than a pulse number of the third pulse signal in the unit time length; In a case where the target backlight brightness is less than a fifth brightness threshold, generate a fifth pulse signal to drive the light-emitting chip; A fifth pulse amplitude of the fifth pulse signal is less than a pulse amplitude represented by a corresponding amplitude parameter, and a pulse number of the fifth pulse signal in the unit time length is a fifth fixed value. The generating of the third pulse signal includes:

15. The display device of claim 13, wherein, Obtaining a ratio of a pulse width parameter to a third parameter threshold; the pulse width parameter corresponds to the target backlight brightness less than the third brightness threshold; the third parameter threshold corresponds to the third brightness threshold; Determining a third pulse amplitude of the third pulse signal according to the ratio and the amplitude parameter; Generating the third pulse signal according to the third pulse amplitude, a pulse number of the third pulse signal in the unit time length, and the third pulse width; the pulse number of the third pulse signal in the unit time length is equal to the third parameter threshold. ​

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