Driving circuit, backlight module and display device

Abstract

A driving circuit, a backlight module and a display device. The driving circuit comprises a power conversion module (200) and a driving module (210). The power conversion module (200) is used for converting an inputted alternating-current voltage or direct-current voltage into a bus voltage and outputting the bus voltage by means of a bus. The driving module (210) comprises N driving units (211), wherein each driving unit (211) comprises a voltage reduction subunit (2111) and a driving subunit (2112); N is a positive integer, and N≥1; an input end of each voltage reduction subunit (2111) is connected to an output end of the power conversion module (200) by means of the bus, and the voltage reduction subunit (2111) is used for reducing the received bus voltage and outputting a first direct-current voltage; and an input end of each driving subunit (2112) is connected to an output end of a corresponding voltage reduction subunit (2111). A voltage reduction subunit (2111) is provided at an input end of each driving subunit (2112) to reduce a bus voltage, thereby reducing the line loss of a bus between the power conversion module (200) and the voltage reduction subunit (2111).

Description

Driving circuit, backlight module and display device TECHNICAL FIELD

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

[0002] The mainstream liquid crystal television backlight driving circuit in the market today is usually composed of a power board and a driving assembly, and the driving assembly is composed of a plurality of LED driving chips. The power board converts 220V alternating current into bus voltage, and outputs the bus voltage to the driving assembly through the bus to supply power to the LED driving chips in the driving assembly.

[0003] With the continuous iteration of products, the size and backlight partition of the existing liquid crystal television are also increasing. However, the existing backlight driving circuit will cause the line loss of the bus to rise sharply with the continuous increase of the backlight partition.

[0004] Therefore, it has become a technical problem urgently to be solved in the industry to provide a driving circuit capable of reducing the line loss of the bus. SUMMARY

[0005] To solve the above problems, the present application provides a driving circuit, a backlight module and a display device to reduce the line loss of the bus.

[0006] The technical scheme of the present application provides a driving circuit, comprising: a power conversion module and a driving module;

[0007] The power conversion module is used to convert the input alternating voltage or direct current voltage into the bus voltage and output through the bus;

[0008] The driving module comprises N driving units, each driving unit comprises a step-down subunit and a driving subunit, N is a positive integer and N>=1, the input end of each step-down subunit is connected to the output end of the power conversion module through the bus, the step-down subunit is used to step down the corresponding received bus voltage and output a first direct current voltage, and the input end of the driving subunit is connected to the output end of the corresponding step-down subunit.

[0009] Optionally, the step-down subunit and the driving subunit are integrated in the same chip.

[0010] Optionally, the power conversion module comprises a power board.

[0011] Optionally, the step-down subunit comprises a step-down charge pump.

[0012] Optionally, the working capacitor in the step-down charge pump is integrated in the chip.

[0013] Optionally, the voltage reduction sub-unit comprises a low-dropout linear voltage regulator.

[0014] Optionally, the voltage reduction sub-unit further comprises a direct current conversion circuit.

[0015] Optionally, the driving sub-unit is a driving chip.

[0016] Correspondingly, the technical scheme of the present application further provides a backlight module, comprising the driving circuit provided by any of the above embodiments.

[0017] Correspondingly, the technical scheme of the present application further provides a display device, comprising the backlight module provided by the above embodiments.

[0018] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0019] In the technical scheme of the present application, a voltage reduction sub-unit is arranged at the input end of each driving sub-unit to reduce the bus voltage, thereby reducing the line loss of the bus between the power conversion module and the voltage reduction sub-unit.

[0020] Further, the voltage reduction sub-unit and the driving sub-unit are integrated in the same chip to further reduce the line loss of the bus and improve the integration of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0021] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0022] Fig. 1 is a circuit structure diagram of an embodiment of a backlight driving circuit;

[0023] Fig. 2 is a module structure diagram one of the driving circuit provided by the technical scheme of the present application;

[0024] Fig. 3 is a module structure diagram two of the driving circuit provided by the technical scheme of the present application.

[0025] Reference signs: 200 - power conversion module; 210 - driving module; 211 - driving unit; 2111 - voltage reduction sub-unit; 2112 - driving sub-unit. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application. The terms "first", "second", "third", "fourth" and the like (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] As described in the background, the existing backlight driving circuit will cause the line loss to rise sharply with the continuous increase of the backlight partition.

[0028] FIG. 1 is a circuit structure diagram of an embodiment of a backlight driving circuit.

[0029] The following takes an embodiment of a backlight driving circuit as an example, and analyzes in detail how the inventor of the present application confirms the specific reasons why the line loss of the existing backlight driving circuit will rise sharply with the continuous increase of the backlight partition, in combination with FIG. 1.

[0030] Please refer to FIG. 1. In this embodiment, the circuit is composed of a power board 100 and a driving assembly 200, and the driving assembly 200 is composed of a plurality of LED driving chips 201. The power board 100 converts 220V alternating current into bus voltage VBKL, and outputs the bus voltage VBKL to the driving assembly 200 through a bus, so as to supply power to the LED driving chips 201 in the driving assembly 200. However, with the continuous increase of the driving chips in the driving assembly 200, the driving power required by the driving assembly 200 will also increase, thereby causing the current flowing through the bus to also increase. Among them, the bus current is equal to the sum of the current input to each driving chip. For example, the current required by each driving chip is 300mA, if only 10 driving chips are needed, then the bus current is equal to 3A; if 100 driving chips are needed, then the bus current increases to 30A. According to the formula (1) of line loss:

[0031] P D =I 2 *R;

[0032] wherein P D for characterizing the line loss of the bus; I for characterizing the bus current; R for characterizing the equivalent impedance of the bus.

[0033] According to formula (1), the bus current is increased by ten times, and the line loss will be increased by one hundred times. If the driving chip continues to increase, the line loss of the bus will be exponentially increased. At the same time, with the increase of the bus current, the circuit components also need to be replaced by large current specification devices, thereby increasing the circuit cost.

[0034] It should be noted that the specific reasons for the rapid increase of the line loss and the circuit cost of the above-mentioned backlight driving circuit with the continuous increase of the backlight partition are found by the inventors of the present application through a large number of research and experiments, and confirming the specific reasons leading to the above-mentioned technical problems is the prerequisite for the research success of the present application scheme; thus, confirming the specific reasons leading to the above-mentioned technical problems is itself an innovation in the field, which is inseparable from the technical scheme of the present application, and as a whole, it is a major technical breakthrough in the field, with significant creativity and value.

[0035] Fig. 2 is a module structure diagram of the driving circuit provided by the technical scheme of the present application.

[0036] Please refer to Fig. 2, the inventors of the present application take the above-mentioned technical problems and the specific reasons corresponding to the technical problems as the starting point, and propose a new driving circuit comprising a power conversion module 200 and a driving module 210.

[0037] The power conversion module 200 is used to convert the input alternating voltage or direct current voltage into the bus voltage, and output through the bus.

[0038] The driving module 210 comprises N driving units 211, each driving unit 211 comprises a step-down sub-unit 2111 and a driving sub-unit 2112, N is a positive integer, and N≥1, the input end of each step-down sub-unit 2111 is connected to the output end of the power conversion module 200 through the bus, the step-down sub-unit 2111 is used to step down the corresponding received bus voltage and output a first direct current voltage, and the input end of the driving sub-unit 2112 is connected to the output end corresponding to the step-down sub-unit 2111.

[0039] The above-mentioned technical scheme of the present application can reduce the line loss of the bus and reduce the circuit cost at the same time. The specific principle is as follows:

[0040] Assuming that the step-down subunit 2111 does not consume power, the power input to the step-down subunit 2111 is equal to the power output to the step-down subunit 2111, and according to formula (2):

[0041] V BKL / V LED = I LED / I BKL

[0042] wherein V BKL is used to represent the bus voltage; V LED is used to represent the first DC voltage; I BKL is used to represent the current input to the step-down subunit 2111; and I LED is used to represent the current output to the step-down subunit 2111.

[0043] If the step-down subunit 2111 has a step-down ratio of 1 to the bus voltage, the first DC voltage is reduced to half of the bus voltage. According to formula (2), I BKL will be reduced to half of I LED . Because I BKL is reduced by half, the current flowing through the bus is also reduced by half. According to formula (1), the line loss of the bus can be reduced by one fourth.

[0044] At the same time, because the current flowing through the bus is reduced, the step-down subunit 2111 and the driving subunit 2112 can both select devices with smaller current specifications, thereby reducing the circuit cost.

[0045] It should be noted that, on the basis of being able to maintain normal driving of the driving subunit 2112, the step-down subunit 2111 has a higher step-down ratio to the bus voltage. Because the step-down subunit 2111 has a higher step-down ratio to the bus voltage, the reduction of the line loss of the bus is greater. Of course, the specific step-down ratio can be set according to requirements, and is not limited herein.

[0046] The circuit structure of the driving circuit provided by the technical scheme of the present application is described in detail as follows:

[0047] FIG. 3 is a second module structure diagram of the driving circuit provided by the technical scheme of the present application.

[0048] Referring to FIG. 3, as a specific embodiment, the step-down subunit 2111 and the driving subunit 2112 are integrated in the same chip, and this embodiment has the beneficial effect of further reducing the line loss of the bus and improving the integration of the circuit.

[0049] As a specific embodiment, the power conversion module 200 comprises a power board. The power board can be any one in the market that can convert 220V AC into DC, which is not limited herein.

[0050] Please refer to Fig. 3, as a specific embodiment, the above analysis assumes that the voltage reduction subunit 2111 does not consume power, but in fact the voltage reduction subunit 2111 will definitely have a certain power loss. Therefore, in order to reduce power loss as much as possible, the voltage reduction subunit 2111 can select a voltage reduction charge pump. Because it does not contain inductance, the output efficiency of the voltage reduction charge pump can be as high as 80% or more. In a further embodiment, the flying capacitor in the charge pump is also integrated in the chip to improve the integration of the circuit. Of course, it can also be placed outside the chip according to the needs. In addition to the voltage reduction charge pump, the voltage reduction subunit 2111 can also select other circuits with voltage reduction function; for example: low dropout linear regulator circuit (LDO circuit) or direct current conversion circuit (DC-DC conversion circuit), which can be selected according to the needs, which is not limited herein.

[0051] Please refer to Fig. 3, as a specific embodiment, the driving subunit 2112 is a driving chip. The driving chip can select any chip in the market that can drive LED lamp beads, which is not limited herein.

[0052] In summary, the driving circuit provided by the embodiment reduces the line loss of the bus between the power conversion module and the voltage reduction subunit by setting a voltage reduction subunit at the input end of each driving subunit to reduce the bus voltage. At the same time, because the current flowing through the bus is reduced, the voltage reduction subunit and the driving subunit can both select devices with smaller current specifications, thereby reducing the cost of the circuit.

[0053] The embodiment of the application also provides a backlight module, comprising the driving circuit provided by the embodiment of the application.

[0054] The embodiment of the application also provides a display device, comprising the backlight module provided by the embodiment of the application.

[0055] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A drive circuit characterized by comprising: The application relates to a driving circuit and a backlight module. The driving circuit comprises a power conversion module and a driving module. The power conversion module is used for converting input AC voltage or DC voltage into bus voltage and outputting through a bus. The driving module comprises N driving units, each of which comprises a step-down subunit and a driving subunit, N is a positive integer and N>=1, the input end of each step-down subunit is connected with the output end of the power conversion module through a bus, the step-down subunit is used for step-down corresponding received bus voltage and outputting first DC voltage, and the input end of the driving subunit is connected with the output end of the corresponding step-down subunit.

2. The drive circuit according to claim 1, characterized by The step-down subunit and the driving subunit are integrated in the same chip.

3. The drive circuit according to claim 1, characterized by The power conversion module comprises a power board.

4. The drive circuit according to claim 1, characterized by The step-down subunit comprises a step-down charge pump.

5. The drive circuit according to claim 1, characterized by The working capacitor in the step-down charge pump is integrated in a chip.

6. The drive circuit of claim 1, wherein The step-down subunit further comprises a low-dropout linear voltage stabilizing circuit.

7. The drive circuit of claim 1, wherein The step-down subunit further comprises a DC conversion circuit.

8. The drive circuit of claim 1, wherein, The driving subunit is a driving chip.

9. A backlight module, characterized in that, The backlight module comprises the driving circuit in any one of claims 1 to 8.

10. A display device, characterized by The backlight module comprises the backlight module in claim 9.

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