Display device and backlight driving control method

Abstract

The display device and backlight drive control method provided by the present application, the display device includes: a power supply unit, a first controller, a second controller, and a light-emitting element; the power supply unit is used to provide a power supply signal to the first controller, the second controller and the light-emitting element; the second controller includes: a first receiving unit, which is used to receive a switching instruction sent by the first controller; a first adjusting unit, which is used to adjust the current flowing through the light-emitting element to a preset first target current amplitude and adjust the current duty ratio of the light-emitting element to 1 according to a predetermined first step length if the switching instruction is a first switching instruction; a second adjusting unit, which is used to adjust the current amplitude of the light-emitting element to a preset second target current amplitude according to a predetermined second step length if the switching instruction is a second switching instruction, and adjust the current duty ratio of the light-emitting element to a predetermined target duty ratio. Thus, the problem of excessive loss of the switch tube connected to the light-emitting element when switching the dimming mode is solved.

Description

Technical Field

[0001] The present application relates to the field of backlight driving, and in particular to a display device and a backlight driving control method. Background Art

[0002] Currently, in order to ensure that when a display device plays a video image with a fixed frame rate, the picture will not experience delays, freezes, tearing, etc. due to the inconsistency between the field rate signal frequency of the display device and the input image frame rate, a variable refresh rate technology is introduced in the relevant technology. The field rate signal is adjusted to keep the field rate signal frequency of the display device consistent with the image frame rate.

[0003] In the related art, a display device usually adopts a pulse width modulation dimming method to provide a backlight for the display device, and when the display device is in a variable refresh rate mode, in order to avoid the display screen of the display device from having a water ripple phenomenon due to the field frequency signal constantly changing, which makes it difficult for the field frequency signal and the on or off frequency of the light-emitting element to be synchronized in real time, a backlight driving method that introduces analog dimming is usually adopted to solve the above problem.

[0004] However, when the two dimming modes in the display device are switched, the signal flowing through the light-emitting element in the display device suddenly changes, which can easily lead to excessive loss and excessive temperature rise in the switching tube connected to the light-emitting element, thereby causing damage to the switching tube and the light-emitting element to fail to emit light. Summary of the invention

[0005] The present application provides a display device and a backlight driving control method, which are used to solve the problem of excessive loss of a switch tube connected to a light-emitting element when switching a dimming mode of a display device in the related art.

[0006] In a first aspect, the present application provides a display device, including: a power supply unit, a first controller, a second controller, and a light-emitting element; wherein:

[0007] The power supply unit is connected to the first controller, the second controller and the light emitting element respectively; the power supply unit is used to provide power supply signals to the first controller, the second controller and the light emitting element; one end of the light emitting element is connected to the power supply unit, and the other end of the light emitting element is connected to the second controller; the first controller is connected to the second controller; the second controller includes:

[0008] A first receiving unit, configured to receive a switching instruction sent by the first controller, wherein the switching instruction is used to instruct switching of a dimming mode;

[0009] A first regulating unit, configured to regulate the current flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length if the switching instruction is a first switching instruction; and to regulate the current duty cycle flowing through the light-emitting element to 1; wherein the first switching instruction is used to instruct switching from a PWM dimming mode to an analog dimming mode;

[0010] A second adjustment unit is used to adjust the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step size if the switching instruction is a second switching instruction; and to adjust the current duty cycle flowing through the light-emitting element to a predetermined target duty cycle; wherein the second switching instruction is used to indicate switching from an analog dimming mode to a PWM dimming mode; wherein the second target current amplitude is greater than the first target current amplitude.

[0011] In some embodiments, the first adjustment unit includes:

[0012] a first regulating module, configured to regulate the current amplitude flowing through the light emitting element to a preset first target current amplitude according to a predetermined first step length if the switching instruction is a first switching instruction;

[0013] The second regulating module is used to regulate the duty cycle of the current flowing through the light-emitting element to 1 if the current amplitude currently flowing through the light-emitting element reaches the first target current amplitude.

[0014] In some embodiments, the second adjusting unit includes:

[0015] a third regulating module, configured to regulate the duty cycle of the current flowing through the light emitting element to a predetermined target duty cycle if the switching instruction is a second switching instruction;

[0016] The fourth regulating module is used to regulate the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step length if the duty cycle of the signal currently flowing through the light-emitting element reaches the target duty cycle.

[0017] In some embodiments, if the current dimming mode is the PWM dimming mode, the second controller further includes:

[0018] A second receiving unit, used for receiving a field frequency signal and a brightness signal sent by the first controller;

[0019] The first output unit is used to output a corresponding driving signal according to the field rate signal and the brightness signal, and the driving signal is used to control the current duty cycle flowing through the light-emitting element and the second target current amplitude.

[0020] In some embodiments, if the current dimming mode is an analog dimming mode, the second controller further includes:

[0021] A third receiving unit, receiving a brightness signal sent by the first controller;

[0022] A generating unit, used for generating a field frequency signal according to preset signal parameters;

[0023] The second output unit is used to output a corresponding driving signal according to the brightness signal and the generated field rate signal, wherein the driving signal is used to control the current duty cycle flowing through the light-emitting element and the first target current amplitude.

[0024] In some embodiments, the first switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is different from the current field frequency signal frequency and the current dimming mode is the PWM dimming mode; the second switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is the same as the current field frequency signal frequency and the current dimming mode is the analog dimming mode.

[0025] In some embodiments, the second controller further comprises:

[0026] A preset unit, used for setting a plurality of current amplitude variation amounts;

[0027] An acquisition unit is used to obtain, for each current amplitude change, the response time of the power supply and the discharge time of the capacitor under the multiple current amplitude changes by performing the following steps: according to the current amplitude change, reducing the current amplitude flowing through the light-emitting element, and determining the corresponding voltage amplitude change; obtaining the response time of the power supply and the discharge time of the capacitor under the current amplitude change, wherein the response time of the power supply is the time required for the output voltage of the power supply to decrease by the voltage amplitude change, and the discharge time of the capacitor is the time required for the voltage across the capacitor to decrease by the voltage amplitude change; wherein one end of the capacitor is connected to the output end of the power supply, and the other end is grounded;

[0028] A determination unit is used to select a first current amplitude change amount from the multiple current amplitude change amounts as the first step length, wherein under the first current amplitude change amount, the discharge time of the capacitor is less than the response time of the power supply.

[0029] In a second aspect, the present application provides a backlight driving control method, which is applied to a second controller in the display device according to the first aspect, and the method includes:

[0030] receiving a switching instruction sent by the first controller, wherein the switching instruction is used to instruct switching of a dimming mode;

[0031] If the switching instruction is a first switching instruction, the current amplitude flowing through the light-emitting element is adjusted to a preset first target current amplitude according to a predetermined first step length; and the current duty cycle flowing through the light-emitting element is adjusted to 1; wherein the first switching instruction is used to instruct switching from a PWM dimming mode to an analog dimming mode;

[0032] If the switching instruction is a second switching instruction, the current amplitude flowing through the light-emitting element is adjusted to a preset second target current amplitude according to a predetermined second step size; and the current duty cycle flowing through the light-emitting element is adjusted to a predetermined target duty cycle; wherein the second switching instruction is used to indicate switching from an analog dimming mode to a PWM dimming mode; wherein the second target current amplitude is greater than the first target current amplitude.

[0033] In some embodiments, if the switching instruction is a first switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length; and adjusting the current duty cycle flowing through the light-emitting element to 1, including:

[0034] If the switching instruction is a first switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length;

[0035] If the current amplitude currently flowing through the light-emitting element reaches the first target current amplitude, the duty cycle of the current flowing through the light-emitting element is adjusted to 1.

[0036] In some embodiments, if the switching instruction is a second switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step length; and adjusting the current duty cycle flowing through the light-emitting element to a predetermined target duty cycle, including:

[0037] If the switching instruction is the second switching instruction, adjusting the duty cycle of the current flowing through the light emitting element to a predetermined target duty cycle;

[0038] If the current duty cycle of the current flowing through the light emitting element currently reaches the target duty cycle, the current amplitude flowing through the light emitting element is adjusted to a preset second target current amplitude according to a predetermined second step length.

[0039] In some embodiments, if the current dimming mode is a PWM dimming mode, the method further includes:

[0040] receiving a field frequency signal and a brightness signal sent by the first controller;

[0041] According to the field frequency signal and the brightness signal, a corresponding driving signal is output, and the driving signal is used to control the current duty cycle flowing through the light-emitting element and the second target current amplitude.

[0042] In some embodiments, if the current dimming mode is an analog dimming mode, the method further includes:

[0043] receiving a brightness signal sent by the first controller;

[0044] Generate a field frequency signal according to preset signal parameters;

[0045] According to the brightness signal and the generated field rate signal, a corresponding driving signal is output, and the driving signal is used to control the current duty cycle flowing through the light-emitting element and the first target current amplitude.

[0046] In some embodiments, the first switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is different from the current field frequency signal frequency and the current dimming mode is the PWM dimming mode; the second switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is the same as the current field frequency signal frequency and the current dimming mode is the analog dimming mode.

[0047] In some embodiments, the method further comprises:

[0048] Setting multiple current amplitude changes;

[0049] For each current amplitude change, the response time of the power supply and the discharge time of the capacitor under the multiple current amplitude changes are obtained by performing the following steps: according to the current amplitude change, the current amplitude flowing through the light-emitting element is reduced, and the corresponding voltage amplitude change is determined; the response time of the power supply and the discharge time of the capacitor under the current amplitude change are obtained, wherein the response time of the power supply is the time required for the output voltage of the power supply to decrease by the voltage amplitude change, and the discharge time of the capacitor is the time required for the voltage across the capacitor to decrease by the voltage amplitude change; wherein one end of the capacitor is connected to the output end of the power supply, and the other end is grounded;

[0050] A first current amplitude change is selected from the multiple current amplitude changes as the first step length, wherein under the first current amplitude change, the discharge time of the capacitor is less than the response time of the power supply.

[0051] The display device and backlight drive control method provided in the present application, the display device includes: a power supply unit, a first controller, a second controller, and a light-emitting element; the power supply unit is used to provide a power supply signal to the first controller, the second controller and the light-emitting element; the second controller includes: a first receiving unit, used to receive a switching instruction sent by the first controller; a first adjusting unit, used to adjust the current flowing through the light-emitting element to a preset first target current amplitude and adjust the current duty cycle flowing through the light-emitting element to 1 according to a predetermined first step length if the switching instruction is a first switching instruction; a second adjusting unit, used to adjust the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step length if the switching instruction is a second switching instruction, and adjust the current duty cycle flowing through the light-emitting element to a predetermined target duty cycle. This solves the problem of excessive loss of the switch tube connected to the light-emitting element when the display device switches the dimming mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0053] Figure 1 A schematic diagram of the structure of a display device provided in this application;

[0054] Figure 2 A schematic diagram of the structure of a dimming unit provided in this application;

[0055] Figure 3 A schematic diagram of the structure of a display device provided in an embodiment of the present application;

[0056] Figure 4 A schematic diagram of the structure of a second controller provided in an embodiment of the present application;

[0057] Figure 5 A schematic diagram of the structure of a second controller provided in an embodiment of the present application;

[0058] Figure 6 A schematic diagram of the structure of a third second controller provided in an embodiment of the present application;

[0059] Figure 7 A schematic diagram of the structure of a fourth second controller provided in an embodiment of the present application;

[0060] Figure 8 A schematic flow chart of a backlight driving control method provided in an embodiment of the present application;

[0061] Fig. 9 A schematic diagram of a dimming mode switching process provided in an embodiment of the present application;

[0062] Fig.10 A schematic diagram of a process for switching another dimming mode provided in an embodiment of the present application;

[0063] Fig.11 A schematic diagram of waveform changes when switching to analog dimming provided in an embodiment of the present application;

[0064] Fig.12 A schematic diagram of another waveform change when switching to analog dimming provided in an embodiment of the present application;

[0065] Fig.13 A schematic diagram of waveform changes when switching to PWM dimming provided in an embodiment of the present application.

[0066] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0067] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0068] At present, with the development of information technology, various display devices have been widely used to facilitate people to obtain information. Figure 1 As shown, Figure 1 A schematic diagram of the structure of a display device provided in the present application. The display device includes a display panel, a light-emitting element, a main board, a power board, a microprocessor, a drive control chip, a light-emitting element, and a dimming unit, wherein a switch tube and a sampling resistor are provided in the dimming unit. The microprocessor, the light-opening tube, and the drive control chip can be provided on a drive board inside the TV. The power board is used to supply power to the main board, the light-emitting element, and the microprocessor and the drive control chip on the drive board.

[0069] Usually, a SOC (System on Chip) controller is also provided on the mainboard, which is used to receive image signals transmitted from an external server or optical fiber, and generate a brightness signal by processing the image signal by the SOC on the mainboard. After that, the mainboard will obtain the field frequency signal and the brightness signal and send them to the microprocessor on the driver board. Among them, the field frequency signal is also the screen refresh frequency, which is used to characterize the number of times the display screen refreshes the picture per second. In a possible implementation, the power board and the mainboard in the display device are combined into one.

[0070] After receiving the field frequency signal and the brightness signal, the microprocessor analyzes them and sends the analyzed signal to the driver chip, so that the driver chip outputs a driving signal to the switch tube connected in series with the light-emitting element according to the analyzed signal, thereby controlling the switch tube to make the light-emitting element emit light.

[0071] At present, the backlight driving mode in display devices is usually PWM (Pulse Width Modulation) dimming mode, such as LD (Local Dimming) display devices. In the PWM dimming mode, the driver control chip controls the brightness of the light-emitting element by controlling the on and off time of the light-emitting element. Figure 2 As shown, Figure 2 A structural schematic diagram of a dimming device provided by the present application. In the figure, a driving control chip is provided. The positive wiring terminal of the light-emitting element is connected to the power input, the negative wiring terminal is connected in series with two switch tubes, and the second switch tube is grounded through a sampling resistor. The drain of the first switch tube is connected to the first output terminal of the driving control chip. In addition, the second output terminal of the driving control chip is connected to the first port of the comparator. The second port of the comparator is connected to one end of the sampling resistor, and the output end of the comparator is connected to the drain of the second switch tube. Among them, the first switch tube is used to receive the duty cycle signal of the driving control signal, and then adjust the duty cycle of the current flowing through the light-emitting element. The first port of the comparator is used to receive the amplitude signal sent by the driving control chip, and the second port of the comparator is used to collect the amplitude of the current currently flowing through the light-emitting element. By comparing the magnitudes of the two amplitudes, the second switch tube is controlled so that the current amplitude flowing through the light-emitting element meets the current amplitude requirement sent by the driving control chip. When the backlight driving mode is PWM dimming, during the light-emitting diode light-emitting process, the first switch tube is always in a periodic on and off state.

[0072] In the related art, in order to ensure that when a display device plays a video image with a fixed frame rate, the picture will not be delayed, stuck, or tear due to the inconsistency between the field rate signal frequency of the display device and the input image frame rate, a variable refresh rate technology is introduced to adjust the field rate signal so that the field rate signal frequency of the display device is consistent with the image frame rate.

[0073] However, when the display device is in a variable refresh rate mode and uses a PWM dimming mode, since the field frequency signal is always in a changing state, the light-emitting diode is always in an on or off switching mode when emitting light in the PWM dimming mode. When the flashing frequency of the light-emitting element is inconsistent with the refresh frequency, water ripples may appear on the display screen.

[0074] Usually, the backlight driving method of introducing analog dimming is adopted to solve the above problems. That is, two dimming modes are set in the display device, namely PWM dimming mode and analog dimming mode. When the display device is in variable refresh rate mode, the traditional PWM dimming mode is converted to analog dimming mode. In the process of analog dimming, when the display device displays the picture, the duty cycle is 1, and the driving control chip changes the brightness of the final displayed picture by controlling the amplitude of the current flowing through the light-emitting element. That is, in the process of analog dimming, Figure 2 The first switch tube is always in the on state, and the second switch tube is still used to adjust the amplitude of the signal flowing through the light-emitting diode. At this time, since the light-emitting diode is always in the emitting state, even if the field frequency signal of the display device changes, there will be no problem of the field frequency signal being out of sync with the light-emitting frequency of the light-emitting element, so that the final displayed picture will not have a problem of poor picture quality due to the continuous change of the field frequency signal.

[0075] However, when the two dimming modes in the display device are switched, the current flowing through the light-emitting element in the display device suddenly changes, which can easily lead to excessive loss and excessive temperature rise in the switching tube connected to the light-emitting element, thereby causing damage to the switching tube and the light-emitting element to fail to emit light.

[0076] Specifically, for example, when the dimming mode is changed from PWM dimming mode to analog dimming mode, the current amplitude flowing through the light-emitting element will suddenly decrease. Since the power supply has a certain response time, when the current in the circuit suddenly changes, the voltage output by the power supply will not change immediately. As the current of the light-emitting element decreases, the voltage applied to both ends of the light-emitting element also suddenly drops, causing the voltage value at both ends of the switch tube connected in series with the light-emitting element to increase, the loss on the switch tube increases, and the temperature rise increases. During the switching process of the above dimming mode, it is easy to cause damage to the switch tube. In the subsequent backlight driving process, the light-emitting element will fail to emit light due to the failure of the switch tube, which will cause the display device to fail to work normally.

[0077] The display device and backlight drive control method provided in this application are intended to solve the above technical problems.

[0078] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0079] Figure 3 This is a schematic diagram of the structure of a display device provided in an embodiment of the present application. Figure 3 As shown, the display device includes: a power supply unit, a first controller, a second controller, and a light-emitting element; wherein the power supply unit is connected to the first controller, the second controller, and the light-emitting element respectively; the power supply unit is used to provide a power supply signal to the first controller, the second controller, and the light-emitting element; one end of the light-emitting element is connected to the power supply unit, and the other end of the light-emitting element is connected to the second controller; the first controller is connected to the second controller. In addition, the driving control chip in the second controller includes: a first receiving unit, a first adjusting unit, and a second adjusting unit.

[0080] The first receiving unit 81 is used to receive a switching instruction sent by the first controller, where the switching instruction is used to instruct the dimming mode of the backlight driver to switch.

[0081] Exemplarily, the display device in the present application has a variable refresh rate function, that is, the display device has two working modes, one is a normal fixed refresh rate mode, and the other is a variable refresh rate mode. In the fixed refresh rate mode, the backlight driving mode uses the PWM dimming mode. In the variable refresh rate mode, the analog dimming mode is selected. When the first receiving unit 81 receives the switching instruction sent by the first controller, it can instruct the second controller in the display device to switch the dimming mode.

[0082] In some embodiments, the switching instruction may be generated by a user triggering a related operation on a display interface of a display device.

[0083] The first adjustment unit 82 is used to adjust the current amplitude flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length if the switching instruction is a first switching instruction; and to adjust the current duty cycle flowing through the light-emitting element to 1; wherein the first switching instruction is used to indicate switching from PWM dimming mode to analog dimming mode.

[0084] For example, when the backlight driving mode is converted from the PWM dimming mode to the analog dimming mode, in order to avoid the problem of excessive switch tube loss caused by the sudden change of the current flowing through the light-emitting element and the delayed response of the power supply, when adjusting the current flowing through the light-emitting element, the current amplitude can be adjusted according to the preset first step length, so that the current amplitude is finally reduced to the first target current amplitude. And the duty cycle of the current flowing through the light-emitting element is adjusted to 1.

[0085] In some embodiments, when adjusting the current amplitude, a step-down method may be used to adjust the current amplitude according to a preset first step length.

[0086] In some embodiments, when the first step length of the current amplitude is adjusted by a step-down method, the first step length may be inconsistent each time the current amplitude is decreased.

[0087] In some embodiments, when the current amplitude is adjusted, it may also decrease at a certain slope.

[0088] In some embodiments, when adjusting the current, the amplitude and duty cycle of the current may be adjusted separately. For example, the amplitude is first adjusted to a specified first amplitude, and then the duty cycle is adjusted to 1.

[0089] In some embodiments, when adjusting the current, the amplitude and duty cycle of the current may be adjusted simultaneously, that is, the amplitude is adjusted according to the first step while the duty cycle of the current is changed.

[0090] In some embodiments, the first switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is different from the frequency of the current field rate signal and the current dimming mode is the PWM dimming mode.

[0091] The second adjustment unit 83 is used to adjust the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step size if the switching instruction is a second switching instruction; and to adjust the current duty cycle flowing through the light-emitting element to a predetermined target duty cycle; wherein the second switching instruction is used to indicate switching from an analog dimming mode to a PWM dimming mode; wherein the second target current amplitude is greater than the first target current amplitude.

[0092] Exemplarily, when the backlight driving mode is converted from analog dimming to PWM dimming, the current amplitude flowing through the light-emitting element can be increased to a preset second target current amplitude according to a predetermined second step size, and the duty cycle of the current can be adjusted to a predetermined duty cycle.

[0093] In some embodiments, the predetermined second step size may be the same as or different from the predetermined first step size in the first adjustment unit 82 .

[0094] In some embodiments, when the second step length of the current amplitude is adjusted by adopting a step-up method, the second step length may be inconsistent each time it increases.

[0095] In some embodiments, when the current amplitude is adjusted, it may also increase at a certain slope.

[0096] In some embodiments, when adjusting the current, the current amplitude and the duty cycle may be adjusted separately. For example, the duty cycle is first adjusted to a predetermined target duty cycle, and then the current amplitude is adjusted according to a second step size.

[0097] In some embodiments, when adjusting the current, the amplitude and the duty cycle of the current may be adjusted simultaneously, that is, the amplitude is adjusted according to the second step size while the duty cycle of the current is changed.

[0098] In some embodiments, the second switching instruction is sent by the first controller when it detects that the frame rate of the image to be displayed is the same as the frequency of the current field rate signal and the current dimming mode is the analog dimming mode.

[0099] In practical applications, the second controller includes a microprocessor, a drive control chip, and a dimming unit. Figure 1 In the architecture shown, the first receiving unit, the first regulating unit and the second regulating unit in the second controller can be integrated in the driving control chip. Among them, the first controller is used to process the image signal received from the outside, and after obtaining the brightness signal, send it to the microprocessor on the driving board. The first receiving unit receives the first switching instruction sent by the first controller, which can be the first switching instruction parsed by the microprocessor, and then receives the brightness signal processed by the microprocessor, so that the first regulating unit can determine the first target current amplitude and duty cycle according to the brightness signal. After that, the first regulating unit controls the frequency of the switch tube connected to the light-emitting element in the dimming unit, thereby changing the current flowing through the light-emitting element. The second receiving unit receives the second switching instruction sent by the first controller, which can be the second switching instruction parsed by the microprocessor, and receives the brightness signal parsed by the microprocessor, so that the second regulating unit can determine the second target current amplitude and the predetermined duty cycle according to the parsed brightness signal. After that, the second regulating unit controls the frequency of the switch tube connected to the light-emitting element to change the current flowing through the light-emitting element. In addition, the power supply unit can be used to provide power supply signals to the devices on the driving board, the first controller and the light-emitting element.

[0100] In this embodiment, during the switching process of the dimming mode, in order to avoid the problem of excessive switching tube losses caused by a sudden change in the amplitude of the current flowing through the light-emitting element, in this embodiment, the first adjustment unit or the second display unit in the display device adjusts the amplitude of the current flowing through the light-emitting element according to a preset step size, thereby avoiding the problem of excessive switching tube losses.

[0101] In some embodiments, Figure 4 As shown, Figure 4 A schematic diagram of the structure of a second controller provided in an embodiment of the present application. In this embodiment, when the backlight driving mode is switched from the PWM dimming mode to the analog dimming mode, that is, when the first adjustment unit adjusts the current flowing through the light-emitting element, the first adjustment unit 82 may specifically include:

[0102] A first regulating module 821, configured to regulate the current amplitude flowing through the light emitting element to a preset first target current amplitude according to a predetermined first step length if the switching instruction is a first switching instruction;

[0103] The second regulating module 822 is configured to regulate the duty cycle of the current flowing through the light emitting element to 1 if the current amplitude currently flowing through the light emitting element reaches the first target current amplitude.

[0104] For example, in this embodiment, when the PWM dimming mode is switched to the analog dimming mode, since the current amplitude flowing through the light-emitting element eventually shows a downward trend, while the current duty cycle is increasing, the current amplitude and the duty cycle can be selected to be adjusted in order. When the amplitude and duty cycle of the current flowing through the light-emitting element are adjusted, if the current duty cycle is increased first, the average value of the current flowing through the light-emitting element will still increase suddenly, which will cause an instantaneous impact on the power supply, causing the overcurrent protection of the power supply, stopping the output signal to the outside, and then causing the light-emitting element to stop emitting light. Therefore, it is preferred to adjust the current amplitude, that is, according to the predetermined first step length, the current amplitude flowing through the light-emitting element is reduced to the first target current amplitude, and then the duty cycle is increased to 1. When the current amplitude drops to the first target current amplitude, the current duty cycle is increased afterwards. Although the average value of the current will still increase, the current value after the average value is increased at this time will cause less impact on the power supply, and will not cause the overcurrent protection of the power supply.

[0105] In this embodiment, in order to avoid the overcurrent protection of the power supply caused by excessive impact on the power supply due to the increase of current during the current regulation process, a first regulation module 821 and a second regulation module 822 are provided in the first regulation unit 82, and the amplitude of the current flowing through the light-emitting element can be adjusted preferentially, that is, the first regulation module 821 is implemented first, and then the duty cycle of the current is adjusted through the second regulation module 822.

[0106] In some embodiments, Figure 5 This is a schematic diagram of the structure of a second controller provided in an embodiment of the present application. The second regulating unit 83 in this embodiment includes:

[0107] The third adjustment module 831 is used to adjust the current duty cycle of the current flowing through the light-emitting element to a predetermined target duty cycle if the switching instruction is the second switching instruction; the fourth adjustment module 832 is used to adjust the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step size if the current duty cycle of the current flowing through the light-emitting element reaches the target duty cycle.

[0108] Exemplarily, when switching from the analog dimming mode to the PWM dimming mode, the amplitude of the current flowing through the light-emitting element tends to increase and the duty cycle of the current decreases. When adjusting the current flowing through the light-emitting element, the current amplitude and the duty cycle can be adjusted in a certain order. In order to avoid the overcurrent protection of the power supply caused by the process of increasing the current amplitude first, at this time, the current duty cycle is preferentially reduced to the target duty cycle through the third adjustment module 831, and then the current amplitude is adjusted to the second target amplitude according to the preset step size through the fourth adjustment module 832, so that when the current amplitude is subsequently increased according to the step size, the current change is small, thereby reducing the impact on the power supply and avoiding the overcurrent protection of the power supply.

[0109] In this embodiment, the third adjustment module 831 is first used to adjust the duty cycle of the current flowing through the light-emitting element to a predetermined target duty cycle, so that when the current amplitude subsequently increases according to the predetermined second step length, the current change is small, thereby reducing the impact on the power supply and avoiding overcurrent protection of the power supply.

[0110] In some embodiments, Figure 6 This is a schematic diagram of the structure of the third second controller provided in the embodiment of the present application. Figure 3 Based on the structure of the second controller shown in FIG. 1 , if the current dimming mode is the PWM dimming mode, the second controller further includes:

[0111] The second receiving unit 84 is used to receive the field frequency signal and the brightness signal sent by the first controller;

[0112] The first output unit 85 is used to output a corresponding driving signal according to the field rate signal and the brightness signal, and the driving signal is used to control the current duty cycle and the second target current amplitude flowing through the light emitting element.

[0113] For example, during the PWM dimming process (i.e., when the refresh rate of the display device is fixed), the duty cycle of the current flowing through the light-emitting element is controlled by the switch tube connected in series with the light-emitting element after the field frequency signal and the brightness signal sent by the first controller are analyzed by the second controller, and the duty cycle of the current flowing through the light-emitting element (i.e., the frequency of the light-emitting element being turned on and off in the light-emitting element) needs to be synchronized with the frequency of the field frequency signal. And the second target current amplitude of the current flowing through the light-emitting element can also be determined by the brightness signal and the field frequency signal.

[0114] In some embodiments, Figure 7 This is a schematic diagram of the structure of the fourth second controller provided in the embodiment of the present application. Figure 3 Based on the structure of the second controller shown in FIG. 1 , if the current dimming mode is the analog dimming mode, the second controller further includes:

[0115] A third receiving unit 86 receives a brightness signal sent by the first controller;

[0116] A generating unit 87, configured to generate a field frequency signal according to preset signal parameters;

[0117] The second output unit 88 is used to output a corresponding driving signal according to the brightness signal and the generated field rate signal, and the driving signal is used to control the current duty cycle and the first target current amplitude flowing through the light emitting element.

[0118] Exemplarily, when the dimming mode is the analog dimming mode (i.e., when the refresh rate of the display device is in a variable state), since the duty cycle of the current flowing through the light-emitting element is 1 during the analog dimming process, the first controller no longer sends a field frequency signal to the second controller, but only sends a brightness signal. In addition, the second controller generates a field frequency signal according to preset signal parameters (e.g., the frequency of the signal), and then the second controller parses the brightness signal and the field frequency signal to generate a driving signal for controlling the duty cycle of the current flowing through the light-emitting element to be 1. The first target current amplitude of the current flowing through the light-emitting element is also determined by the field frequency signal and the brightness signal.

[0119] In a possible implementation manner, in order to determine a predetermined first step length when the PWM dimming mode is changed to the analog dimming mode, the second controller further includes:

[0120] A preset unit, used for setting a plurality of current amplitude variation amounts;

[0121] The acquisition unit is used to obtain the response time of the power supply and the discharge time of the capacitor under multiple current amplitude changes by executing the following steps for each current amplitude change: according to the current amplitude change, the current amplitude flowing through the light-emitting element is reduced, and the corresponding voltage amplitude change is determined; the response time of the power supply and the discharge time of the capacitor under the current amplitude change are obtained, wherein the response time of the power supply is the time required for the output voltage of the power supply to decrease by the voltage amplitude change, and the discharge time of the capacitor is the time required for the voltage across the capacitor to decrease by the voltage amplitude change; wherein one end of the capacitor is connected to the output end of the power supply, and the other end is grounded.

[0122] The determination unit is used to select a first current amplitude change amount from a plurality of current amplitude change amounts as a first step length, wherein under the first current amplitude change amount, the discharge time of the capacitor is less than the response time of the power supply.

[0123] For example, when the PWM dimming mode is changed to the analog dimming mode, the output voltage of the power supply will also change due to the change of the current flowing through the light-emitting element, but the response of the power supply has a time delay, and the voltage output by the power supply can reach a stable output state after a period of time. Since a capacitor is usually connected to the output end of the power supply, that is, one end of the capacitor is connected to the output end of the power supply, and the other end of the capacitor is grounded, it can play a role in filtering and shaping the output signal of the power supply. However, the capacitor itself is an energy storage element. When the output voltage of the power supply changes, the capacitor itself will also discharge, and the part of the energy released by the capacitor due to the voltage change will be borne by the switch tube. When the discharge time of the capacitor is greater than the response time of the power supply, the energy time borne by the switch tube will increase, thereby increasing the loss of the switch tube, and the time for the switch tube to withstand the impact is extended.

[0124] Therefore, in order to reduce the loss on the switch tube and reduce the time of the switch tube loss, it is necessary to satisfy that the discharge time of the capacitor is less than the response time of the power supply. The discharge time of the capacitor and the response time of the power supply are both related to the amplitude change of the current in the light-emitting element.

[0125] Specifically, when determining the predetermined first step length when the current amplitude is transformed, a plurality of current amplitude changes can be first set by a preset unit. Under each current amplitude change, the voltage amplitude change is determined according to the current amplitude signal, and the time required for the output voltage of the power supply to decrease by the voltage amplitude change (i.e., the response time of the power supply) and the time required for the voltage across the capacitor to decrease by the voltage amplitude change (i.e., the response time of the capacitor) under each current amplitude change are obtained by an acquisition unit. Afterwards, the determination unit selects the current amplitude change whose capacitor discharge time is less than the power supply response time from each current amplitude change as the first step length.

[0126] In this embodiment, by selecting a suitable first step length so that the discharge time of the capacitor is less than the power supply response time, the time during which the switch tube impact caused by the capacitor discharge is extended can be shortened. This implementation effectively shortens the time the switch tube withstands the impact, thereby reducing the switch tube loss, achieving protection for the switch tube, and avoiding the problem of damage to the switch tube when the switch tube withstands the impact for a long time.

[0127] Figure 8 A flow chart of a backlight driving control method provided in an embodiment of the present application is shown in FIG. Figure 8 As shown, this method is applied to Figure 3 The second controller in the display device shown, the method comprises the following steps:

[0128] S101, receiving a switching instruction sent by a first controller, where the switching instruction is used to instruct switching a dimming mode.

[0129] Exemplarily, the display device in the present application has a variable refresh rate function, that is, the display device has two working modes, one is a normal fixed refresh rate mode, and the other is a variable refresh rate mode. In the fixed refresh rate mode, the backlight driver uses the PWM dimming mode. In the variable refresh rate mode, the analog dimming method is selected. When receiving a switching instruction, the second controller in the display device can be instructed to switch the dimming mode.

[0130] In some embodiments, the switching instruction may be generated by a user triggering a related operation on a display interface of the display device.

[0131] S102. If the switching instruction is a first switching instruction, then according to a predetermined first step length, the current amplitude flowing through the light-emitting element is adjusted to a preset first target current amplitude; and the current duty cycle flowing through the light-emitting element is adjusted to 1; wherein the first switching instruction is used to indicate switching from PWM dimming mode to analog dimming mode.

[0132] For example, when the backlight driving mode is converted from the PWM dimming mode to the analog dimming mode, in order to avoid the problem of excessive switch tube loss caused by the sudden change of the current flowing through the light-emitting element and the delayed response of the power supply, when adjusting the current flowing through the light-emitting element, the current amplitude can be adjusted according to the preset first step length, so that the current amplitude is finally reduced to the first target current amplitude. And the duty cycle of the current flowing through the light-emitting element is adjusted to 1.

[0133] In some embodiments, when adjusting the current amplitude, a step-down method may be used to adjust the current amplitude according to a preset first step length.

[0134] In some embodiments, when the first step length of the current amplitude is adjusted by a step-down method, the first step length may be inconsistent each time the current amplitude is decreased.

[0135] In some embodiments, when the current amplitude is adjusted, it may also decrease at a certain slope.

[0136] In some embodiments, when adjusting the current, the amplitude and duty cycle of the current may be adjusted separately. For example, the amplitude is first adjusted to a specified first amplitude, and then the duty cycle is adjusted to 1.

[0137] In some embodiments, when adjusting the current, the amplitude and duty cycle of the current may be adjusted simultaneously, that is, the amplitude is adjusted according to the first step while the duty cycle of the current is changed.

[0138] S103. If the switching instruction is a second switching instruction, then according to a predetermined second step size, the current amplitude flowing through the light-emitting element is adjusted to a preset second target current amplitude; and the current duty cycle flowing through the light-emitting element is adjusted to a predetermined target duty cycle; wherein the second switching instruction is used to indicate switching from an analog dimming mode to a PWM dimming mode; wherein the second target current amplitude is greater than the first target current amplitude.

[0139] Exemplarily, when the backlight driving mode is converted from the analog dimming mode to the PWM dimming mode, the current amplitude flowing through the light-emitting element can be increased to a preset second target current amplitude according to a predetermined second step length, and the duty cycle of the current can be adjusted to a predetermined duty cycle. In some embodiments, the second step length in this step can be the same as the first step length in step S102, or it can be different.

[0140] In some embodiments, when the second step length of the current amplitude is adjusted by adopting a step-up method, the second step length may be inconsistent each time it increases.

[0141] In some embodiments, when the current amplitude is adjusted, it may also increase at a certain slope.

[0142] In some embodiments, when adjusting the current, the current amplitude and the duty cycle may be adjusted separately. For example, the duty cycle is first adjusted to a predetermined target duty cycle, and then the current amplitude is adjusted according to a second step size.

[0143] In some embodiments, when adjusting the current, the amplitude and the duty cycle of the current may be adjusted simultaneously, that is, the amplitude is adjusted according to the second step size while the duty cycle of the current is changed.

[0144] In this embodiment, during the switching process of the dimming mode, in order to avoid the problem of excessive switching tube losses caused by a sudden change in the amplitude of the current flowing through the light-emitting element, in this embodiment, the amplitude of the current flowing through the light-emitting element is adjusted according to a preset step size, thereby avoiding the problem of excessive switching tube losses.

[0145] In some embodiments, when the backlight driving mode is switched from the PWM dimming mode to the analog dimming mode, the following steps may be used to adjust the current (that is, when executing step S102, the following steps may be used to implement the current adjustment). Fig. 9 As shown, Fig. 9 A schematic diagram of a dimming mode switching process provided in an embodiment of the present application, the steps include:

[0146] S1021: If the switching instruction is a first switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length;

[0147] S1022. If the current amplitude currently flowing through the light-emitting element reaches the first target current amplitude, adjust the duty cycle of the current flowing through the light-emitting element to 1.

[0148] For example, in this embodiment, when the PWM dimming mode is switched to the analog dimming mode, since the current amplitude flowing through the light-emitting element eventually shows a downward trend, while the current duty cycle is increasing, the current amplitude and the duty cycle can be selected to be adjusted in order. When the amplitude and duty cycle of the current flowing through the light-emitting element are adjusted, if the current duty cycle is increased first, the average value of the current flowing through the light-emitting element will still increase suddenly, which will cause an instantaneous impact on the power supply, causing the overcurrent protection of the power supply, stopping the output signal to the outside, and then causing the light-emitting element to stop emitting light. Therefore, it is preferred to adjust the current amplitude, that is, according to the predetermined first step length, the current amplitude flowing through the light-emitting element is reduced to the first target current amplitude, and then the duty cycle is increased to 1. When the current amplitude drops to the first target current amplitude, the current duty cycle is increased afterwards. Although the average value of the current will still increase, the current value after the average value is increased at this time will cause less impact on the power supply, and will not cause the overcurrent protection of the power supply.

[0149] In this embodiment, in order to avoid excessive impact on the power supply caused by the increase of current during the current regulation process and cause overcurrent protection of the power supply, the amplitude of the current flowing through the light-emitting element can be adjusted first, and then the duty cycle of the current can be adjusted.

[0150] In some embodiments, when the backlight driving mode is switched from the analog dimming mode to the PWM dimming mode, the following steps may be used to adjust the current (that is, when executing step S103, the following steps may be used to implement the current adjustment). Fig.10 As shown, Fig.10 A schematic diagram of another dimming mode switching process provided in an embodiment of the present application, the steps include:

[0151] S1031, if the switching instruction is the second switching instruction, adjusting the duty cycle of the current flowing through the light-emitting element to a predetermined target duty cycle;

[0152] S1032: If the current duty cycle of the current flowing through the light-emitting element reaches the target duty cycle, adjust the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step length.

[0153] For example, when switching from analog dimming mode to PWM dimming mode, the amplitude of the current flowing through the light-emitting element tends to increase and the duty cycle of the current decreases. When adjusting the current flowing through the light-emitting element, the current amplitude and the duty cycle can be adjusted in a certain order. In order to avoid the overcurrent protection of the power supply caused by increasing the current amplitude first, at this time, the method of preferentially reducing the current duty cycle is adopted, so that when the current amplitude increases in the step size in the subsequent step, the current change is small, thereby reducing the impact on the power supply and avoiding the overcurrent protection of the power supply.

[0154] In this embodiment, by first adjusting the duty cycle of the current flowing through the light-emitting element to a predetermined target duty cycle, the current changes less when the current amplitude subsequently increases according to a predetermined second step length, thereby reducing the impact on the power supply and avoiding overcurrent protection of the power supply.

[0155] In some embodiments, the switching instruction received in step S101 may be generated by the first controller. Specifically, the first switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is different from the field frequency signal frequency of the current display device and the current dimming mode is the PWM dimming mode. The second switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is the same as the current field frequency signal frequency and the current dimming mode is the analog dimming mode.

[0156] In some embodiments, if the current dimming mode is the PWM dimming mode, the backlight driving control method further includes:

[0157] Receive the field frequency signal and the brightness signal sent by the first controller; output the corresponding driving signal according to the field frequency signal and the brightness signal, the driving signal is used to control the current duty cycle and the second target current amplitude flowing through the light-emitting element.

[0158] For example, during the PWM dimming process (i.e., when the refresh rate of the display device is fixed), the duty cycle of the current flowing through the light-emitting element is controlled by the field frequency signal and the brightness signal sent by the first controller after being parsed by the second controller, and at this time, the duty cycle of the current flowing through the light-emitting element (i.e., the frequency of the light-emitting element being turned on and off in the light-emitting element) needs to be synchronized with the frequency of the field frequency signal. And the second target current amplitude of the current flowing through the light-emitting element is also determined by the brightness signal and the field frequency signal.

[0159] In some embodiments, if the current dimming mode of the display device is an analog dimming mode, the backlight driving control method further includes:

[0160] Receive a brightness signal sent by the first controller; generate a field rate signal according to preset signal parameters; output a corresponding drive signal according to the brightness signal and the generated field rate signal, the drive signal is used to control the current duty cycle and the first target current amplitude flowing through the light-emitting element.

[0161] Exemplarily, when the dimming mode is the analog dimming mode (i.e., when the refresh rate of the display device is in a variable state), since the duty cycle of the current flowing through the light-emitting element is 1 during the analog dimming process, the first controller no longer sends a field frequency signal to the second controller, but only sends a brightness signal. In addition, the second controller generates a field frequency signal based on preset signal parameters (e.g., the frequency of the signal), and then generates a driving signal for controlling the duty cycle of the current flowing through the light-emitting element to be 1 after parsing the brightness signal and the field frequency signal. The first target current amplitude of the current flowing through the light-emitting element is also determined by the field frequency signal and the brightness signal.

[0162] In some embodiments, in order to determine the predetermined first step length when the PWM dimming mode is converted into the analog dimming mode, it can be implemented in the following manner:

[0163] Setting multiple current amplitude changes;

[0164] For each current amplitude change, the response time of the power supply and the discharge time of the capacitor under multiple current amplitude changes are obtained by performing the following steps: according to the current amplitude change, the current amplitude flowing through the light-emitting element is reduced, and the corresponding voltage amplitude change is determined; the response time of the power supply and the discharge time of the capacitor under the current amplitude change are obtained, wherein the response time of the power supply is the time required for the output voltage of the power supply to decrease by the voltage amplitude change, and the discharge time of the capacitor is the time required for the voltage across the capacitor to decrease by the voltage amplitude change; wherein one end of the capacitor is connected to the output end of the power supply, and the other end is grounded;

[0165] A first current amplitude change is selected from a plurality of current amplitude change amounts as a first step length, wherein under the first current amplitude change amount, the discharge time of the capacitor is less than the response time of the power supply.

[0166] For example, when the PWM dimming mode is changed to the analog dimming mode, the output voltage of the power supply will also change due to the change of the current flowing through the light-emitting element, but the response of the power supply has a time delay, and the voltage output by the power supply can reach a stable output state after a period of time. Since a capacitor is usually connected to the output end of the power supply, that is, one end of the capacitor is connected to the output end of the power supply, and the other end of the capacitor is grounded, it can play a role in filtering and shaping the output signal of the power supply (that is, the power supply unit in this embodiment can be composed of a power supply and a capacitor). However, the capacitor itself is an energy storage element. When the output voltage of the power supply changes, the capacitor itself will also discharge, and the part of the energy released by the capacitor due to the voltage change will be borne by the switch tube. When the discharge time of the capacitor is greater than the response time of the power supply, the energy time borne by the switch tube will increase, thereby increasing the loss of the switch tube, and the time for the switch tube to withstand the impact is extended.

[0167] like Fig.11 As shown, Fig.11 A schematic diagram of waveform changes when switching to analog dimming provided for an embodiment of the present application. In the figure, curve 1 represents the voltage drop curve on the switch tube, and curve 2 represents a schematic diagram of the current change flowing through the light-emitting element (the step-like change in the figure mainly presents the change in the amplitude of the current. Since the frequency of the current signal is usually high, the adjustment change of the duty cycle is not directly shown in the figure, wherein the vertical line between the upper contour line and the lower contour line corresponding to curve 1 only represents that the voltage drop change has a duty cycle, and does not represent the duty cycle change frequency. The vertical lines in the other curve contour lines have the same meaning). In curve 2, the current signal first steps down the amplitude of the current, and then changes the duty cycle of the current signal (combined with the diagram, the duty cycle is adjusted after point A in the figure, and the duty cycle is adjusted to 1). When the amplitude of the current decreases each time, at this time, the switch tube will bear a certain impact, the voltage drop value at both ends of the switch tube increases, and due to the influence of capacitor discharge, the time the switch tube is subjected to the impact will be extended. The distance between the two dotted lines in the figure represents the loss time of the switch tube when the amplitude decreases for the second time. Fig.11 At the point marked ①, there is a brief disappearance of the current and the signal on the switch tube. This is because during the switching process from PWM dimming to analog dimming mode, the first controller stops sending the field frequency signal to the second controller, and the second controller is required to generate a field frequency signal with preset signal parameters, so there will be a brief signal loss.

[0168] Therefore, in order to reduce the loss on the switch tube and reduce the time of the switch tube loss, it is necessary to satisfy that the discharge time of the capacitor is less than the response time of the power supply. The discharge time of the capacitor and the response time of the power supply are both related to the amplitude change of the current in the light-emitting element.

[0169] Specifically, when determining the predetermined first step length when the current amplitude is transformed, a plurality of current amplitude changes can be set first. Under each current amplitude change, the voltage amplitude change is determined according to the current amplitude signal, and the time required for the output voltage of the power supply to decrease by the voltage amplitude change (i.e., the response time of the power supply) and the time required for the voltage across the capacitor to decrease by the voltage amplitude change (i.e., the response time of the capacitor) under each current amplitude change are obtained. From each current amplitude change, the current amplitude change whose capacitor discharge time is less than the power supply response time is selected as the first step length.

[0170] Fig.12 A schematic diagram of another waveform change when switching to analog dimming provided in an embodiment of the present application. Fig.12 In the figure, curve 3 represents the voltage drop curve when the second switch tube is turned on, and curve 4 represents the schematic diagram of the current change flowing through the light-emitting element. In curve 4, the current signal first drops the current amplitude in a step-by-step manner, and then changes the duty cycle of the current signal. Every time the current amplitude drops, the switch tube will still bear a certain impact. The time consumed by the two circled peaks in the figure represents the impact time on the switch tube every time the current drops in a step-by-step manner. Fig.12 At the middle mark ①, there is a brief disappearance of the current and power output signal. This is because during the switching process from PWM dimming to analog dimming mode, the first controller stops sending the field frequency signal to the second controller, and the second controller is required to generate a field frequency signal with preset signal parameters, so there will be a brief signal loss.

[0171] This embodiment selects a suitable first step length so that the discharge time of the capacitor is shorter than the power supply response time, thereby reducing the time for the switch tube impact to be extended due to the capacitor discharge. Fig.11 and Fig.12 , Fig.11 The distance between the two dotted lines represents the impact time of the switch tube. Fig.12 The circled stage is the period when the switch tube is subjected to impact under the implementation of this embodiment. After comparison, it can be seen that this embodiment effectively shortens the time when the switch tube is subjected to impact, thereby reducing the loss of the switch tube, realizing the protection of the switch tube, and avoiding the problem of damage to the switch tube when the switch tube is subjected to impact for a long time.

[0172] Fig.13 A schematic diagram of waveform changes when switching to PWM dimming provided in an embodiment of the present application. Fig.13In the figure, curve 5 represents the change curve of the power supply output voltage, and curve 6 represents the schematic diagram of the change of the current flowing through the light-emitting element. When the current signal switches in the dimming mode, the duty cycle of the current signal is first reduced, and then the current amplitude is increased at a certain rate. In addition, during the above-mentioned change of the current signal, the voltage signal output by the power supply does not exceed the maximum output voltage value of the power supply, thereby avoiding the problem of the power supply interrupting the output due to overcurrent protection. Fig.13 At the point marked ①, there is a brief disappearance of the current signal. This is because during the switching process from the analog dimming mode to the PWM dimming mode, the first controller starts to send a field frequency signal to the second controller. The second controller needs to convert from automatically generating a field frequency signal to receiving and processing the field frequency signal sent by the first controller, resulting in a brief loss of the signal.

[0173] The device provided in this embodiment is used to implement the technical solution provided by the above method. Its implementation principle and technical effect are similar and will not be described in detail.

[0174] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

[0175] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A display device, characterized in that: include: A power supply unit, a first controller, a second controller, and a light emitting element; wherein, The power supply unit is connected to the first controller, the second controller and the light emitting element respectively; the power supply unit is used to provide power supply signals to the first controller, the second controller and the light emitting element; one end of the light emitting element is connected to the power supply unit, and the other end of the light emitting element is connected to the second controller; the first controller is connected to the second controller; the second controller includes: A first receiving unit, configured to receive a switching instruction sent by the first controller, wherein the switching instruction is used to instruct switching of a dimming mode; A first regulating unit, configured to regulate the current flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length if the switching instruction is a first switching instruction; and to regulate the current duty cycle flowing through the light-emitting element to 1; wherein the first switching instruction is used to instruct switching from a PWM dimming mode to an analog dimming mode; A second adjustment unit is used to adjust the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step size if the switching instruction is a second switching instruction; and to adjust the current duty cycle flowing through the light-emitting element to a predetermined target duty cycle; wherein the second switching instruction is used to indicate switching from an analog dimming mode to a PWM dimming mode; wherein the second target current amplitude is greater than the first target current amplitude.

2. The display device according to claim 1, characterized in that The first adjusting unit comprises: a first regulating module, configured to regulate the current amplitude flowing through the light emitting element to a preset first target current amplitude according to a predetermined first step length if the switching instruction is a first switching instruction; The second regulating module is used to regulate the duty cycle of the current flowing through the light-emitting element to 1 if the current amplitude currently flowing through the light-emitting element reaches the first target current amplitude.

3. The display device according to claim 1, characterized in that The second adjusting unit comprises: a third regulating module, configured to regulate the duty cycle of the current flowing through the light emitting element to a predetermined target duty cycle if the switching instruction is a second switching instruction; The fourth regulating module is used to regulate the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step length if the duty cycle of the signal currently flowing through the light-emitting element reaches the target duty cycle.

4. The display device according to claim 1, characterized in that If the current dimming mode is the PWM dimming mode, the second controller further includes: A second receiving unit, used for receiving a field frequency signal and a brightness signal sent by the first controller; The first output unit is used to output a corresponding driving signal according to the field rate signal and the brightness signal, and the driving signal is used to control the current duty cycle flowing through the light-emitting element and the second target current amplitude.

5. The display device according to claim 1, characterized in that If the current dimming mode is the analog dimming mode, the second controller further includes: A third receiving unit, receiving a brightness signal sent by the first controller; A generating unit, used for generating a field frequency signal according to preset signal parameters; The second output unit is used to output a corresponding driving signal according to the brightness signal and the generated field rate signal, wherein the driving signal is used to control the current duty cycle flowing through the light-emitting element and the first target current amplitude.

6. The display device according to claim 1, characterized in that The first switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is different from the current field frequency signal and the current dimming mode is the PWM dimming mode; the second switching instruction is sent when the first controller detects that the frame rate of the image to be displayed is the same as the current field frequency signal and the current dimming mode is the analog dimming mode.

7. The display device according to any one of claims 1 to 6, characterized in that: The second controller also includes: A preset unit, used for setting a plurality of current amplitude variation amounts; An acquisition unit is used to obtain, for each current amplitude change, the response time of the power supply and the discharge time of the capacitor under the multiple current amplitude changes by performing the following steps: according to the current amplitude change, reducing the current amplitude flowing through the light-emitting element, and determining the corresponding voltage amplitude change; obtaining the response time of the power supply and the discharge time of the capacitor under the current amplitude change, wherein the response time of the power supply is the time required for the output voltage of the power supply to decrease by the voltage amplitude change, and the discharge time of the capacitor is the time required for the voltage across the capacitor to decrease by the voltage amplitude change; wherein one end of the capacitor is connected to the output end of the power supply, and the other end is grounded; A determination unit is used to select a first current amplitude change amount from the multiple current amplitude change amounts as the first step length, wherein under the first current amplitude change amount, the discharge time of the capacitor is less than the response time of the power supply.

8. A backlight driving control method, characterized in that: The second controller used in the display device according to claim 1, the method comprising: receiving a switching instruction sent by the first controller, wherein the switching instruction is used to instruct switching of a dimming mode; If the switching instruction is a first switching instruction, the current amplitude flowing through the light-emitting element is adjusted to a preset first target current amplitude according to a predetermined first step length; and the current duty cycle flowing through the light-emitting element is adjusted to 1; wherein the first switching instruction is used to instruct switching from a PWM dimming mode to an analog dimming mode; If the switching instruction is a second switching instruction, the current amplitude flowing through the light-emitting element is adjusted to a preset second target current amplitude according to a predetermined second step size; and the current duty cycle flowing through the light-emitting element is adjusted to a predetermined target duty cycle; wherein the second switching instruction is used to indicate switching from an analog dimming mode to a PWM dimming mode; wherein the second target current amplitude is greater than the first target current amplitude.

9. The method according to claim 8, characterized in that If the switching instruction is a first switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length; And, adjusting the duty cycle of the current flowing through the light emitting element to 1, comprising: If the switching instruction is a first switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset first target current amplitude according to a predetermined first step length; If the current amplitude currently flowing through the light-emitting element reaches the first target current amplitude, the duty cycle of the current flowing through the light-emitting element is adjusted to 1.

10. The method according to claim 8, characterized in that If the switching instruction is a second switching instruction, adjusting the current amplitude flowing through the light-emitting element to a preset second target current amplitude according to a predetermined second step length; And, adjusting the duty cycle of the current flowing through the light emitting element to a predetermined target duty cycle, comprising: If the switching instruction is the second switching instruction, adjusting the duty cycle of the current flowing through the light emitting element to a predetermined target duty cycle; If the current duty cycle of the current flowing through the light emitting element currently reaches the target duty cycle, the current amplitude flowing through the light emitting element is adjusted to a preset second target current amplitude according to a predetermined second step length.

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