Backlight driving circuit and display device

Abstract

Embodiments of the present application provide a backlight driving circuit and a display device, wherein the backlight driving circuit comprises: a boosting unit, an output end of the boosting unit being connected to a first end of a backlight load; a dimming unit, the dimming unit comprising a first resistor, a first end of the first resistor being grounded; a feedback biasing unit, the feedback biasing unit comprising a second resistor, a first end of the second resistor being connected to the output end of the boosting unit; and a control unit, the control unit being connected to the boosting unit, the dimming unit and the feedback biasing unit, a feedback end of the control unit being connected to a second end of the first resistor, the control unit being configured to: in a first control mode, control the backlight load and the first resistor to form a first loop, and adjust the output of the boosting unit according to a first voltage signal of the feedback end; or in a second control mode, control the second resistor and the first resistor to form a second loop, and adjust the output of the boosting unit according to a second voltage signal of the feedback end. In this way, the voltage / current of the output of the boosting unit can be controlled to be constant, and the display effect is improved.

Description

Technical Field

[0001] This application relates to the field of display technology, specifically to a backlight driving circuit and a display device. Background Technology

[0002] With the development of display technology, the requirements for backlight control of display devices are becoming increasingly stringent. In existing technologies, the backlight power supply of most display devices such as televisions, smart terminals, and smart tablets adopts single PWM dimming, single analog dimming IC (integrated circuit) dimming, and PWM + analog dimming methods.

[0003] The existing PWM+analog dimming method integrates the analog dimming part and the PWM dimming part into a single IC, which is costly and lacks design flexibility. Summary of the Invention

[0004] This application provides a backlight driving circuit and a display device that can control the output voltage / current of the boost unit to be constant, thereby improving the display effect.

[0005] This application provides a backlight driving circuit, which includes: a boost unit, the output terminal of which is connected to a first terminal of a backlight load; a dimming unit, which includes a first resistor, the first terminal of which is grounded; a feedback bias unit, which includes a second resistor, the first terminal of which is connected to the output terminal of the boost unit; and a control unit, which is connected to the boost unit, the dimming unit, and the feedback bias unit, the feedback terminal of which is connected to the second terminal of the first resistor. The control unit is configured to: in a first control mode, control the backlight load and the first resistor to form a first circuit, and adjust the output of the boost unit according to a first voltage signal from the feedback terminal; or in a second control mode, control the second resistor and the first resistor to form a second circuit, and adjust the output of the boost unit according to a second voltage signal from the feedback terminal.

[0006] In some embodiments, the dimming unit includes a first switch, a first end of which is connected to a second end of the backlight load, and a second end of which is connected to a second end of the first resistor; the feedback bias unit includes a second switch, a first end of which is connected to a second end of the second resistor, and a second end of which is connected to a second end of the first resistor; the control unit is configured to: in a first control mode, control the first switch to be turned on and control the second switch to be turned off; or in a second control mode, control the first switch to be turned off and control the second switch to be turned on.

[0007] In some embodiments, the feedback bias unit further includes a third resistor, the first end of which is connected to the second end of the second switch, and the second end of which is connected to the second end of the first resistor.

[0008] In some embodiments, the feedback bias unit further includes: a first capacitor, the first end of which is connected to the first end of the second resistor; and a fourth resistor, the first end of which is connected to the second end of the first capacitor, and the second end of which is connected to the second end of the second resistor.

[0009] In some embodiments, the control terminal of the second switch is connected to the power supply voltage terminal; the dimming unit further includes: a third switch, the control terminal of the third switch is connected to the control unit, the first terminal of the third switch is connected to the power supply voltage terminal, and the second terminal of the third switch is grounded; a fourth switch, the control terminal of the fourth switch is connected to the first terminal of the third switch, the first terminal of the fourth switch is connected to both the power supply voltage terminal and the control terminal of the first switch, and the second terminal of the fourth switch is grounded; the control unit is configured to: in a first control mode, control the third switch to be turned on, so that the fourth switch is turned off and the second switch is turned off, thereby turning on the first switch; or in a second control mode, control the third switch to be turned off, so that the fourth switch is turned on and the second switch is turned on, thereby turning off the first switch.

[0010] In some embodiments, the first switch is an NMOS transistor, and the second, third, and fourth switches are NPN transistors.

[0011] In some embodiments, the dimming unit further includes: a fifth resistor, the first end of which is connected to the first end of the fourth switch, and the second end of which is connected to the control end of the first switch; a sixth resistor, the first end of which is connected to the first end of the fourth switch, and the second end of which is connected to the power supply voltage terminal; a seventh resistor, the first end of which is connected to the first end of the third switch, and the second end of which is connected to the power supply voltage terminal; and an eighth resistor, the first end of which is connected to the control end of the second switch, and the second end of which is connected to the power supply voltage terminal.

[0012] In some embodiments, the dimming unit further includes a diode, the input of which is connected to the second terminal of the first resistor, and the output of which is grounded.

[0013] In some embodiments, the backlight driving circuit further includes a filtering unit, wherein the input terminal of the filtering unit is connected to the second terminal of the first resistor, and the output terminal of the filtering unit is connected to the feedback terminal of the control unit.

[0014] This application also provides a display device, which includes the backlight driving circuit as described above.

[0015] The backlight driving circuit provided in this application includes: a boost unit, the output terminal of which is connected to a first terminal of a backlight load; a dimming unit, which includes a first resistor, the first terminal of which is grounded; a feedback bias unit, which includes a second resistor, the first terminal of which is connected to the output terminal of the boost unit; and a control unit, which is connected to the boost unit, the dimming unit, and the feedback bias unit. The feedback terminal of the control unit is connected to the second terminal of the first resistor. The control unit is configured to: in a first control mode, control the backlight load and the first resistor to form a first circuit, and adjust the output of the boost unit according to a first voltage signal from the feedback terminal; or in a second control mode, control the second resistor and the first resistor to form a second circuit, and adjust the output of the boost unit according to a second voltage signal from the feedback terminal. By adding a dimming unit and a feedback bias unit to the backlight driving circuit in the above manner, the resistors in the two units form different circuits under different driving modes. When the backlight load is working, the voltage / current of the working circuit is detected, and when the backlight load is not working, the voltage / current of the output terminal of the boost unit is detected. Based on the feedback, the output of the boost unit is controlled, which can ensure that the output of the boost unit is constant, thereby improving the display effect. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the first embodiment of the backlight driving circuit provided in this application;

[0018] Figure 2 This is a schematic diagram of the structure of the second embodiment of the backlight driving circuit provided in this application;

[0019] Figure 3 This is a schematic diagram of the structure of the third embodiment of the backlight driving circuit provided in this application;

[0020] Figure 4 This is a schematic diagram of the structure of the fourth embodiment of the backlight driving circuit provided in this application;

[0021] Figure 5 This is a schematic diagram of the structure of the fifth embodiment of the backlight driving circuit provided in this application;

[0022] Figure 6 This is a schematic diagram of the structure of the sixth embodiment of the backlight driving circuit provided in this application;

[0023] Figure 7This is a schematic diagram of the structure of the seventh embodiment of the backlight driving circuit provided in this application;

[0024] Figure 8 This is a schematic diagram of an embodiment of the display device provided in this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0028] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0029] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0030] See Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the backlight driving circuit provided in this application. The backlight driving circuit 100 includes a boost unit 10, a dimming unit 20, a feedback bias unit 30, and a control unit 40.

[0031] The output terminal of the boost unit 10 is connected to the first terminal of the backlight load; the dimming unit 20 includes a first resistor ( Figure 1 (Not shown), the first terminal of the first resistor is grounded; the feedback bias unit 30 includes a second resistor ( Figure 1 (Not shown), the first end of the second resistor is connected to the output end of the boost unit 10; the control unit 40 is connected to the boost unit 10, the dimming unit 20 and the feedback bias unit 30, and the feedback terminal FB of the control unit 40 is connected to the second end of the first resistor.

[0032] Specifically, the control unit 40 is connected to the boost unit 10, the feedback bias unit 30, and the dimming unit 20 to control their operation. The output terminal of the boost unit 10 is used to output the driving voltage signal, i.e., the voltage LED+ at the positive terminal of the backlight load. The dimming unit 20 is connected to the second terminal (negative terminal LED-) of the backlight load and the feedback bias unit 30. The feedback bias unit is also used to connect to the boost unit 10 to input the driving voltage signal LED+.

[0033] In this embodiment, the control unit 40 is configured to: in a first control mode, control the backlight load and the dimming unit 20 (including a first resistor) to form a first loop, with the first resistor acting as a sampling resistor to sample a first voltage signal, and the control unit 40 adjusting the output of the boost unit 10 according to the first voltage signal at the feedback terminal FB; or in a second control mode, control the second resistor of the feedback bias unit 30 and the first resistor of the dimming unit 20 to form a second loop, with the first resistor acting as a sampling resistor to sample a second voltage signal, and the control unit 40 adjusting the output of the boost unit according to the second voltage signal at the feedback terminal FB.

[0034] Further reading Figure 2 , Figure 2 This is a schematic diagram of the structure of the second embodiment of the backlight driving circuit provided in this application. The backlight driving circuit 100 includes a boost unit 10, a dimming unit 20, a feedback bias unit 30, and a control unit 40.

[0035] The output terminal of the boost unit 10 is connected to the first terminal of the backlight load; the dimming unit 20 includes a first resistor ( Figure 1 (Not shown), the first terminal of the first resistor is grounded; the feedback bias unit 30 includes a second resistor ( Figure 1 (Not shown), the first end of the second resistor is connected to the output end of the boost unit 10; the control unit 40 is connected to the boost unit 10, the dimming unit 20 and the feedback bias unit 30, and the feedback terminal FB of the control unit 40 is connected to the second end of the first resistor.

[0036] Specifically, the dimming unit 20 includes a first switch T1 and a first resistor R1. The first end of the first resistor is grounded, the first end of the first switch T1 is connected to the second end of the backlight load LED-, and the second end of the first switch T1 is connected to the second end of the first resistor R1. The feedback bias unit 30 includes a second switch T2 and a second resistor R2. The first end of the second resistor R2 is connected to the output terminal of the boost unit 10, the first end of the second switch T2 is connected to the second end of the second resistor R2, and the second end of the second switch T2 is connected to the second end of the first resistor R1.

[0037] The control unit 40 is configured to: in a first control mode, control the first switch T1 to be turned on and control the second switch T2 to be turned off, the backlight load and the first resistor R1 form a first circuit, the first resistor R1 acts as a sampling resistor to sample the first voltage signal, and the control unit 40 adjusts the output of the boost unit 10 according to the first voltage signal at the feedback terminal FB; or in a second control mode, control the first switch T1 to be turned off and control the second switch T2 to be turned on, the second resistor and the first resistor R1 form a second circuit, the first resistor R1 acts as a sampling resistor to sample the second voltage signal, and the control unit 40 adjusts the output of the boost unit 10 according to the second voltage signal at the feedback terminal FB.

[0038] Optionally, in one embodiment, the dimming unit 20 is a PWM (Pulse Width Modulation) dimming unit, that is, the control unit 40 receives the analog dimming signal from the motherboard and then converts the analog dimming signal into a corresponding PWM signal. For example, when the PWM signal is high, the first switch T1 is turned on and the second switch T2 is turned off; when the PWM signal is low, the first switch T1 is turned off and the second switch T2 is turned on.

[0039] Furthermore, the voltage signal at the feedback terminal FB of the control unit 40 corresponds to the first terminal of the first resistor R1. In the first mode, the voltage signal at this node also reflects the operating current of the backlight load. Therefore, the voltage signal can be used to determine whether the backlight load is operating in a constant voltage / current environment. If not, the control unit 40 can control the output of the boost unit 10 to ensure that the operating voltage / current of the backlight load is constant, thereby improving the display effect. In the second mode, the voltage signal at the first terminal of the first resistor R1 is unrelated to the backlight load. Instead, it is obtained by directly dividing the voltage signal output by the boost unit 10 (the voltage divider between R2 and R1). The output of the boost unit 10 is directly detected and fed back to ensure that the operating voltage / current of the backlight load is constant, thereby improving the display effect.

[0040] The backlight driving circuit provided in this embodiment includes: a boost unit, the output terminal of which is connected to a first terminal of the backlight load; a dimming unit, which includes a first resistor, the first terminal of which is grounded; a feedback bias unit, which includes a second resistor, the first terminal of which is connected to the output terminal of the boost unit; and a control unit, which is connected to the boost unit, the dimming unit, and the feedback bias unit. The feedback terminal of the control unit is connected to the second terminal of the first resistor. The control unit is configured to: in a first control mode, control the backlight load and the first resistor to form a first circuit, and adjust the output of the boost unit according to the first voltage signal at the feedback terminal; or in a second control mode, control the second resistor and the first resistor to form a second circuit, and adjust the output of the boost unit according to the second voltage signal at the feedback terminal. By adding a dimming unit and a feedback bias unit to the backlight driving circuit in the above manner, the resistors in the two units form different circuits in different driving modes. When the backlight load is working, the voltage / current of the working circuit is detected; when the backlight load is not working, the voltage / current of the output terminal of the boost unit is detected, and the output of the boost unit is controlled according to the feedback. This ensures that the output of the boost unit is constant, thereby improving the display effect.

[0041] See Figure 3 , Figure 3 This is a schematic diagram of the structure of the third embodiment of the backlight driving circuit provided in this application. The backlight driving circuit 100 includes a boost unit 10, a dimming unit 20, a feedback bias unit 30, and a control unit 40.

[0042] The output terminal of the boost unit 10 is connected to the first terminal of the backlight load; the dimming unit 20 includes a first resistor ( Figure 1 (Not shown), the first terminal of the first resistor is grounded; the feedback bias unit 30 includes a second resistor ( Figure 1(Not shown), the first end of the second resistor is connected to the output end of the boost unit 10; the control unit 40 is connected to the boost unit 10, the dimming unit 20 and the feedback bias unit 30, and the feedback terminal FB of the control unit 40 is connected to the second end of the first resistor.

[0043] Specifically, the dimming unit 20 includes a first switch T1 and a first resistor R1. The first end of the first resistor is grounded, the first end of the first switch T1 is connected to the second end of the backlight load LED-, and the second end of the first switch T1 is connected to the second end of the first resistor R1. The feedback bias unit 30 includes a second switch T2 and a second resistor R2. The first end of the second resistor R2 is connected to the output terminal of the boost unit 10, the first end of the second switch T2 is connected to the second end of the second resistor R2, and the second end of the second switch T2 is connected to the second end of the first resistor R1.

[0044] The dimming unit 20 also includes a third switch T3 and a fourth switch T4. The control terminal of the second switch T2 is connected to the power supply voltage terminal V0. The control terminal of the third switch T3 is connected to the control unit 40. The first terminal of the third switch T3 is connected to the power supply voltage terminal V0, and the second terminal of the third switch T3 is grounded. The control terminal of the fourth switch T4 is connected to the first terminal of the third switch T3. The first terminal of the fourth switch T4 is connected to the power supply voltage terminal V0 and the control terminal of the first switch T1, and the second terminal of the fourth switch T4 is grounded.

[0045] In this embodiment, the first switch is an NMOS transistor, and the second, third, and fourth switches are NPN transistors.

[0046] Control unit 40 is configured as follows:

[0047] In the first control mode, the PWM signal input to the control terminal of the third switch T3 is at a high level, controlling the third switch T3 to conduct, thereby pulling down the voltage of the control terminals of the second switch T2 and the fourth switch T4, causing the fourth switch T4 to be turned off and the second switch T2 to be turned off. The control terminal of the first switch T1 is connected to the power supply voltage terminal V0, and the first switch T1 is turned on. Therefore, the backlight load and the first resistor R1 form a first circuit. The first resistor R1 acts as a sampling resistor to sample the first voltage signal. The control unit 40 adjusts the output of the boost unit 10 according to the first voltage signal of the feedback terminal FB.

[0048] In the second control mode, the PWM signal input to the control terminal of the third switch T3 is at a low level, controlling the third switch T3 to be turned off, so that the control terminals of the second switch T2 and the fourth switch T4 are both at a high level, the fourth switch T4 is turned on, the second switch T2 is turned on, and the turn on of the fourth switch T4 further pulls down the level of the control terminal of the first switch T1, thereby turning off the first switch T1; therefore, the second resistor and the first resistor R1 form a second circuit, and the first resistor R1 acts as a sampling resistor to sample the second voltage signal. The control unit 40 adjusts the output of the boost unit 10 according to the second voltage signal of the feedback terminal FB.

[0049] See Figure 4 , Figure 4 This is a schematic diagram of the structure of the fourth embodiment of the backlight driving circuit provided in this application. The fourth embodiment further adds a third resistor R3 based on the third embodiment. The first end of the third resistor R3 is connected to the second end of the second switch T2, and the second end of the third resistor R3 is connected to the second end of the first resistor R1.

[0050] In the second control mode, the second resistor R2, the third resistor R3 and the first resistor R1 form a second circuit. The first resistor R1 serves as a sampling resistor to sample the second voltage signal. The control unit 40 adjusts the output of the boost unit 10 according to the second voltage signal at the feedback terminal FB.

[0051] See Figure 5 , Figure 5 This is a schematic diagram of the structure of the fifth embodiment of the backlight driving circuit provided in this application. The backlight driving circuit 100 includes a boost unit 10, a dimming unit 20, a feedback bias unit 30, and a control unit 40.

[0052] The output terminal of the boost unit 10 is connected to the first terminal of the backlight load; the dimming unit 20 includes a first resistor ( Figure 1 (Not shown), the first terminal of the first resistor is grounded; the feedback bias unit 30 includes a second resistor ( Figure 1 (Not shown), the first end of the second resistor is connected to the output end of the boost unit 10; the control unit 40 is connected to the boost unit 10, the dimming unit 20 and the feedback bias unit 30, and the feedback terminal FB of the control unit 40 is connected to the second end of the first resistor.

[0053] Specifically, the dimming unit 20 includes a first switch T1 and a first resistor R1. The first end of the first resistor is grounded, the first end of the first switch T1 is connected to the second end of the backlight load LED-, and the second end of the first switch T1 is connected to the second end of the first resistor R1. The feedback bias unit 30 includes a second switch T2 and a second resistor R2. The first end of the second resistor R2 is connected to the output terminal of the boost unit 10, the first end of the second switch T2 is connected to the second end of the second resistor R2, and the second end of the second switch T2 is connected to the second end of the first resistor R1.

[0054] The dimming unit 20 also includes a third switch T3 and a fourth switch T4. The control terminal of the second switch T2 is connected to the power supply voltage terminal V0. The control terminal of the third switch T3 is connected to the control unit 40. The first terminal of the third switch T3 is connected to the power supply voltage terminal V0, and the second terminal of the third switch T3 is grounded. The control terminal of the fourth switch T4 is connected to the first terminal of the third switch T3. The first terminal of the fourth switch T4 is connected to the power supply voltage terminal V0 and the control terminal of the first switch T1, and the second terminal of the fourth switch T4 is grounded.

[0055] The feedback bias unit 30 further includes a first capacitor C1 and a fourth resistor R4. The first end of the first capacitor C1 is connected to the first end of the second resistor R2; the first end of the fourth resistor R4 is connected to the second end of the first capacitor C1, and the second end of the fourth resistor R4 is connected to the second end of the second resistor R2.

[0056] In this embodiment, the first capacitor C1 and the fourth resistor R4 serve as loop compensation and voltage buffer.

[0057] See Figure 6 , Figure 6 This is a schematic diagram of the structure of the sixth embodiment of the backlight driving circuit provided in this application. The sixth embodiment adds a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8 to the above embodiments.

[0058] Specifically, the first end of the fifth resistor R5 is connected to the first end of the fourth switch T4, and the second end of the fifth resistor R5 is connected to the control end of the first switch T1; the first end of the sixth resistor R6 is connected to the first end of the fourth switch T4, and the second end of the sixth resistor R6 is connected to the power supply voltage terminal V0; the first end of the seventh resistor R7 is connected to the first end of the third switch T3, and the second end of the seventh resistor T7 is connected to the power supply voltage terminal V0; the first end of the eighth resistor R8 is connected to the control end of the second switch T2, and the second end of the eighth resistor R8 is connected to the power supply voltage terminal V0.

[0059] See Figure 7 , Figure 7 This is a schematic diagram of the structure of the seventh embodiment of the backlight driving circuit provided in this application. The seventh embodiment adds a ninth resistor R9 and a second capacitor C2 to the above embodiments.

[0060] In this embodiment, the first terminal of the ninth resistor R9 is connected to the first terminal of the third resistor R3, and the second terminal of the ninth resistor R9 is connected to the feedback terminal FB of the control unit 40; the first terminal of the second capacitor C2 is connected to the second terminal of the ninth resistor R9, and the second terminal of the second capacitor C2 is grounded. In this embodiment, the ninth resistor R9 and the second capacitor C2 constitute a low-pass filter unit.

[0061] Furthermore, the seventh embodiment adds a diode D1 based on the above embodiments. The input terminal of diode D1 is connected to the second terminal of the first resistor R1, and the output terminal of diode D1 is grounded.

[0062] See Figure 8 , Figure 8 This is a schematic diagram of an embodiment of the display device provided in this application. The display device 800 includes the backlight driving circuit 100 as described in the above embodiment.

[0063] Optionally, the display device 800 may specifically be a liquid crystal display (LCD), which includes a display panel and a backlight panel. The backlight panel is mainly composed of an array of lamps (generally LEDs), and the backlight driving circuit 100 described above may be disposed on the backlight panel to drive the lamps.

[0064] The display screen provided in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A backlight driving circuit, characterized in that, The backlight driving circuit includes: The boost unit is connected to the first terminal of the backlight load. A dimming unit, the dimming unit including a first resistor, the first terminal of the first resistor being grounded; A feedback bias unit, the feedback bias unit including a second resistor, the first end of the second resistor being connected to the output terminal of the boost unit; A control unit, connected to the boost unit, the dimming unit, and the feedback bias unit, wherein the feedback terminal of the control unit is connected to the second terminal of the first resistor, and the control unit is configured to: In the first control mode, the backlight load and the first resistor are controlled to form a first circuit, and the output of the boost unit is adjusted according to the first voltage signal at the feedback terminal; or In the second control mode, the second resistor and the first resistor are controlled to form a second circuit, and the output of the boost unit is adjusted according to the second voltage signal at the feedback terminal; The dimming unit includes a first switch, a first end of which is connected to the second end of the backlight load, and a second end of which is connected to the second end of the first resistor. The feedback bias unit includes a second switch, the first end of which is connected to the second end of the second resistor, and the second end of which is connected to the second end of the first resistor. The control unit is configured to: In the first control mode, the first switch is turned on, and the second switch is turned off; or In the second control mode, the first switch is controlled to be turned off, and the second switch is controlled to be turned on.

2. The backlight driving circuit according to claim 1, characterized in that, The feedback bias unit further includes: A third resistor, the first end of which is connected to the second end of the second switch, and the second end of which is connected to the second end of the first resistor.

3. The backlight driving circuit according to claim 1, characterized in that, The feedback bias unit further includes: A first capacitor, wherein a first terminal of the first capacitor is connected to a first terminal of the second resistor; A fourth resistor, the first end of which is connected to the second end of the first capacitor, and the second end of which is connected to the second end of the second resistor.

4. The backlight driving circuit according to claim 1, characterized in that, The control terminal of the second switch is connected to the power supply voltage terminal; The dimming unit also includes: The third switch has its control terminal connected to the control unit, its first terminal connected to the power supply voltage terminal, and its second terminal grounded. The fourth switch has its control terminal connected to the first terminal of the third switch, the first terminal of the fourth switch is connected to the power supply voltage terminal and the control terminal of the first switch, and the second terminal of the fourth switch is grounded. The control unit is configured to: In the first control mode, the third switch is turned on, causing the fourth switch and the second switch to turn off, thereby turning on the first switch; or In the second control mode, the third switch is turned off, so that the fourth switch and the second switch are turned on, thereby turning off the first switch.

5. The backlight driving circuit according to claim 4, characterized in that, The first switch is an NMOS transistor, and the second, third, and fourth switches are NPN transistors.

6. The backlight driving circuit according to claim 4, characterized in that, The dimming unit also includes: The fifth resistor has its first end connected to the first end of the fourth switch and its second end connected to the control end of the first switch. The sixth resistor has its first end connected to the first end of the fourth switch and its second end connected to the power supply voltage terminal. The seventh resistor has its first end connected to the first end of the third switch and its second end connected to the power supply voltage terminal. The eighth resistor has its first end connected to the control terminal of the second switch and its second end connected to the power supply voltage terminal.

7. The backlight driving circuit according to claim 1, characterized in that, The dimming unit also includes: A diode, wherein the input terminal of the diode is connected to the second terminal of the first resistor, and the output terminal of the diode is grounded.

8. The backlight driving circuit according to claim 1, characterized in that, The backlight driving circuit also includes: A filtering unit, wherein the input terminal of the filtering unit is connected to the second terminal of the first resistor, and the output terminal of the filtering unit is connected to the feedback terminal of the control unit.

9. A display device, characterized in that, The display device includes a backlight driving circuit as described in any one of claims 1-8.

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