CN108597458B

CN108597458B - LOCAL DIMMING backlight driving circuit, device and liquid crystal display equipment

Info

Publication number: CN108597458B
Application number: CN201810391332.5A
Authority: CN
Inventors: 王伟; 谢仁礼
Original assignee: Shenzhen TCL New Technology Co Ltd
Current assignee: Shenzhen TCL New Technology Co Ltd
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2020-12-08
Anticipated expiration: 2038-04-26
Also published as: CN108597458A

Abstract

The invention discloses a LOCAL DIMMING backlight driving circuit, a LOCAL DIMMING backlight driving device and liquid crystal display equipment, wherein the circuit comprises L LED drivers, L X N row driving switches, L X (16-N) column driving switches and a backlight module, the backlight module comprises L X (16-N) groups of LED lamp bars, and the number of each group of LED lamp bars is N; a plurality of control ends of each LED driver are correspondingly connected with the controlled ends of the N row driving switches and the (16-N) column driving switches one by one; the input end of each row driving switch is used for being connected with a direct-current power supply, the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the LED lamp strips in the (16-N) group are correspondingly connected with the input ends of the (16-N) column driving switches in a one-to-one mode, and the output ends of the column driving switches are grounded. The invention improves the driving utilization rate of a single LED driver.

Description

LOCAL DIMMING backlight driving circuit, device and liquid crystal display equipment

Technical Field

The invention relates to the technical field of backlight display, in particular to a LOCAL DIMMING backlight driving circuit, a LOCAL DIMMING backlight driving device and liquid crystal display equipment.

Background

At present, more and more computers, televisions, etc. have backlight driving systems from using liquid crystal display devices to Local dimming backlight technology (Local backlight technology), and the number of backlight partitions tends to increase with the development of the technology. A conventional Local dimming driving chip can generally drive LED light bars of 16 channels, and in large-size television backlight requiring many partitions, a corresponding number of driving chips need to be configured, so that the cost of backlight driving is increased, and the application of the Local dimming backlight technology to middle and low-end machines is limited.

Disclosure of Invention

The invention mainly aims to provide a LOCAL DIMMING backlight driving circuit, a LOCAL DIMMING backlight driving device and liquid crystal display equipment, aiming at improving the driving utilization rate of a single LED driver.

In order to achieve the above object, the present invention provides a LOCAL DIMMING backlight driving circuit, which includes L LED drivers, L × N row driving switches, L × 16-N column driving switches, and a backlight module, where the backlight module includes L × 16-N groups of LED light bars, and the number of each group of LED light bars is N; a plurality of control ends of each LED driver are correspondingly connected with controlled ends of N row driving switches and (16-N) column driving switches one by one; the input end of each row driving switch is used for being connected with a direct-current power supply, the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the LED lamp strips in the (16-N) group are correspondingly connected with the input ends of the (16-N) column driving switches in a one-to-one mode, and the output ends of the column driving switches are grounded; wherein the content of the first and second substances,

the L LED drivers are used for outputting a time sequence control signal to control the L X N row driving switches to be conducted row by row and outputting a column driving control signal to control the L X (16-N) column driving switches to be turned on/off;

l is greater than or equal to 1, N is greater than or equal to 2 and less than or equal to 8.

Preferably, the LOCAL DIMMING backlight driving circuit comprises L LOCAL DIMMING backlight driving branches, and the L LOCAL DIMMING backlight driving branches are arranged in parallel; wherein the content of the first and second substances,

each LOCAL DIMMING backlight driving branch comprises an LED driver, N row driving switches and (16-N) column driving switches.

Preferably, the LOCAL DIMMING backlight driving circuit further comprises an MCU, and the MCU is respectively connected to the L LOCAL DIMMING backlight driving branches; the MCU is used for receiving an external control instruction, demodulating a control signal and outputting the demodulated control signal to each LED driver.

Preferably, the LOCAL DIMMING backlight driving circuit further includes a communication circuit, and the communication circuit is serially connected between the MCU and the LED driver.

Preferably, the LOCAL DIMMING backlight driving circuit further comprises a driving power supply, and an output end of the driving power supply is connected to input ends of the L × N row driving switches;

and the driving power supply is used for driving the corresponding LED lamp set in the backlight module to work when the corresponding row driving switch in the L X N row driving switches is closed and the corresponding column driving switch in the L X (16-N) column driving switches is closed.

Preferably, the LED driver includes a plurality of row driving registers and a plurality of column driving registers, the plurality of row driving registers are configured to generate and output timing control signals, and the plurality of column driving registers are configured to generate and output column driving control signals.

Preferably, the LED driver further comprises a current control register for generating and outputting a current regulation control signal.

The invention also provides a LOCAL DIMMING backlight driving device, which comprises the LOCAL DIMMING backlight driving circuit; the LOCAL DIMMING backlight driving circuit comprises L LED drivers, L X N row driving switches, L X (16-N) column driving switches and a backlight module, wherein the backlight module comprises L X (16-N) groups of LED light bars, and the number of each group of LED light bars is N; a plurality of control ends of each LED driver are correspondingly connected with controlled ends of N row driving switches and (16-N) column driving switches one by one; the input end of each row driving switch is used for being connected with a direct-current power supply, the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the LED lamp strips in the (16-N) group are correspondingly connected with the input ends of the (16-N) column driving switches in a one-to-one mode, and the output ends of the column driving switches are grounded; the L LED drivers are used for outputting a time sequence control signal to control the L X N row driving switches to be conducted row by row and outputting a column driving control signal to control the L X (16-N) column driving switches to be turned on/off;

The invention also provides a liquid crystal display device comprising the LOCAL DIMMING backlight driving device.

The LOCAL DIMMING backlight driving circuit is provided with L LED drivers, L X N row driving switches, L X (16-N) column driving switches and a backlight module according to the number of the backlight modules of the liquid crystal display device, wherein the backlight module comprises L X (16-N) groups of LED lamp bars, and the number of each group of LED lamp bars is N; and the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the (16-N) group LED lamp strips are correspondingly connected with the input ends of the (16-N) column driving switches one by one to form a driving circuit of the LED lamp group, and the LED driver generates corresponding number of time sequence control signals according to the number of the row driving switches and outputs the time sequence control signals to the corresponding row driving switches so as to realize the periodic line-by-line closing of the row driving switches, and when receiving an externally input LOCAL DIMMING signal, the corresponding column driving switches are controlled to be closed, so that the LED lamp strips which are simultaneously closed by the row driving switches and the column driving switches are driven to be lightened, and the LOCAL backlight driving/adjusting is realized. By the arrangement, one LED driver is adopted to drive N row driving switches and (16-N) column driving switches, twenty or even sixty-four LED lamp bars can be driven to work, and the driving capability of the single LED driver is improved. According to the invention, the driving utilization rate of a single LED driver is improved, so that the configuration quantity of the LED drivers is integrally reduced, the problem of complex control algorithm of the MCU caused by controlling a plurality of driving chips to work simultaneously is solved, and the production cost and the design difficulty of the backlight driver are reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a functional block diagram of a LOCAL DIMMING backlight driver circuit according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of an embodiment of the LOCAL DIMMING backlight driver circuit shown in FIG. 1;

FIG. 3 is a functional block diagram of a LOCAL DIMMING backlight driver circuit according to another embodiment of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.

In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The invention provides a LOCAL DIMMING backlight driving circuit.

The liquid crystal display device can be a display device with a display panel, such as a mobile phone, a tablet computer, a notebook computer, a palm computer, a liquid crystal television and the like. The Liquid Crystal television may be a Liquid Crystal Display device such as a TFT-LCDTFT-LCD (Thin Film Transistor Liquid Crystal Display).

In the liquid crystal display television, a local dimming driving circuit is mostly arranged to drive the backlight LED lamp to work, and the local dimming driving circuit plays a very important role in improving the density of the backlight light source, reducing the driving cost and the like, so that the local dimming circuit driven in a time-sharing mode can be applied to a high-resolution large-size television needing to further increase the number of backlight partitions.

The LCD color tv using the LED backlight technology has the advantages of long service life, power and energy saving, and convenient driving. There are two LED backlight schemes: one is direct type, and a plurality of lamps are directly arranged below the screen; the other type is a side-in type, a plurality of lamps are distributed on the periphery of the screen, and light is uniformly guided to the LCD screen through a light guide plate. Both of the above LED backlight schemes are commonly used, wherein the direct type has more advantages, and the most important advantage is that LOCAL DIMMING (LOCAL backlight DIMMING) function can be realized. LOCAL DIMMING divides the lamps behind the screen into a plurality of groups, such as 32 groups, 64 groups and 128 groups, each group is composed of a plurality of lamp beads in a series connection mode, generally, the more the groups are, the thinner the groups are, the better the DIMMING effect is, and the brightness of each group of lamps is determined by the brightness of the picture, so that the display effect is better, and more energy and power are saved. The LOCAL DIMMING system is divided into a driving device and a light bar, wherein the driving device receives a LOCAL DIMMING signal provided by a T-CON board or a mainboard through a special driving IC, demodulates the LOCAL DIMMING signal and then sends the demodulated LOCAL DIMMING signal to a plurality of 16-channel drivers.

That is, one driver can drive 16 groups of LED lamps to operate, and so on, 32 groups of LED lamps require two drivers, 64 groups require four drivers, 128 groups require eight drivers to operate, and in the case of large-sized tv backlight, many partitions are required. Therefore, a plurality of driving chips are required to be configured for implementation, the cost of the driving chips is high, and the plurality of driving chips are controlled to work simultaneously, so that the control algorithm of the MCU is complex, the production cost and the design difficulty of the backlight driver are increased, and the application and development of the local dimming backlight technology on middle and low-end machines are limited.

Referring to fig. 1, in an embodiment of the present invention, the LOCAL DIMMING backlight driving circuit includes L LED drivers 10, L × N row driving switches 20, L × N column driving switches 30, and a backlight module 40, where the backlight module 40 includes L × 16-N groups of LED light bars, and the number of each group of LED light bars is N; a plurality of control ends of each LED driver are correspondingly connected with controlled ends of N row driving switches and (16-N) column driving switches one by one; the input ends of the N row driving switches are used for being connected with a direct-current power supply, the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the LED lamp strips in the (16-N) group are correspondingly connected with the input ends of the (16-N) column driving switches in a one-to-one mode, and the output ends of the (16-N) column driving switches are grounded; wherein the content of the first and second substances,

the L LED drivers are configured to output timing control signals to control the L × N row driving switches 20 to be turned on row by row, and output column driving control signals to control the L × N (16-N) column driving switches to be turned on/off;

l is greater than or equal to 1 and N is greater than or equal to 2.

In this embodiment, the lamp group or referred to as a light bar may be placed horizontally or vertically, and each light bar may have 4 to 10 lamps, with different numbers of lamps being set according to different sizes of the screen. The line driving switch can be realized by a transistor, a MOS (metal oxide semiconductor) transistor, an IGBT (insulated gate bipolar transistor), a TFT (thin film transistor) and other switching tubes, or can also be realized by an electronic switch such as a relay.

The number of L may be one, or more than one, and may be specifically set according to the size of the liquid crystal display device, such as a mobile phone, a tablet computer, a notebook computer, a palmtop computer, or a liquid crystal television, that is, the number of the backlight modules 40 of the liquid crystal display device. For example, in a 55-inch lcd tv, the number of the light bars is generally 128, and the number of L may be set to 2. In a notebook computer or the like, the number of L may be set to 1. In practical applications, the setting may be specifically performed according to design requirements, such as dimming effect, brightness, and the like, and is not limited herein.

Referring to fig. 2, it can be understood that in the embodiment where the LOCAL DIMMING backlight driving circuit LED driver is set to be 1, the LED driver includes sixteen control signal output terminals (PWM 1-PWM 16), the number of N may be set to be two, or more than two, and when N is set to be two, referring to fig. 2, fig. 2 is a schematic circuit structure diagram when N is set to be 2 in the LOCAL DIMMING backlight driving circuit. In fig. 2, the number of the row driving switches is two (K1, K2), and the number of the column driving switches is fourteen (K3 to K16), and the corresponding backlight module 40 includes 14 groups of LED light bars, each group of LED light bars includes 2 light bars (D1A, D1B); (D2A, D2B); … (D14A, D14B). The total number of the LED light bars is 2 × 14, that is, one LED driver can simultaneously drive 28 light bars to be turned on or turned off, or one driver can simultaneously drive 28 light bars to have brightness. When the number of N is three, that is, the number of the row driving switches is three, the number of the column driving switches is thirteen, and the corresponding backlight module 40 includes 13 groups of LED light bars, and the number of each group of LED light bars is 3. The total number of the LED lamp bars is 3 × 13, that is, one LED driver can simultaneously drive 39 lamp bars to be turned on or off. Or one driver can drive the brightness of 39 light bars simultaneously. By analogy, when the number of the row driving switches is eight, the number of the column driving switches is also eight, the corresponding backlight module 40 comprises 8 groups of LED light bars, and the number of each group of LED light bars is 8. The total number of the LED light bars is 8 by 8, that is, one LED driver can simultaneously drive 64 light bars to be turned on or off. Or one driver can drive the brightness of 64 light bars simultaneously.

In this embodiment, the LED driver generates a corresponding number of timing control signals according to the number of the row driving switches, and outputs the timing control signals to the corresponding row driving switches, so as to periodically drive the row driving switches to be closed row by row, and when receiving an externally input LOCAL DIMMING signal, controls the corresponding column driving switches to be closed, so as to light up the LED light bars that are simultaneously closed by the row driving switches and the column driving switches, thereby achieving the purpose of LOCAL DIMMING (LOCAL backlight adjustment). The LOCAL DIMMING signal comprises an LED lamp driving signal and a brightness adjustment control signal, and the LED lamp driving signal may be a control signal for controlling the on/off of the LED lamp; the brightness adjustment control signal can be implemented by controlling the conduction degree of the column driving switch according to the magnitude of the column driving signal output by the LED driver. The current output to the LED lamp is controlled by adjusting the conduction degree of the column driving switches, so that the brightness of the LED lamp is adjusted. The LED driver may control one column driving switch to be turned on according to the LOCAL DIMMING signal, or may control a plurality of column driving switches to be turned on at the same time, which is not limited herein.

The LOCAL DIMMING backlight driving circuit is provided with L LED drivers 10, L X N row driving switches 20, L X (16-N) column driving switches 30 and a backlight module 40 according to the number of the backlight module 40 of the liquid crystal display device, wherein the backlight module 40 comprises L X (16-N) groups of LED lamp bars, and the number of each group of LED lamp bars is N; and the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the (16-N) group LED lamp strips are correspondingly connected with the input ends of the (16-N) column driving switches one by one to form a driving circuit of the LED lamp group, and the LED driver generates corresponding number of time sequence control signals according to the number of the row driving switches and outputs the time sequence control signals to the corresponding row driving switches so as to realize the periodic line-by-line closing of the row driving switches, and when receiving an externally input LOCAL DIMMING signal, the corresponding column driving switches are controlled to be closed, so that the LED lamp strips which are simultaneously closed by the row driving switches and the column driving switches are driven to be lightened, and the LOCAL backlight driving/adjusting is realized. By the arrangement, one LED driver is adopted to drive N row driving switches and (16-N) column driving switches, twenty or even sixty-four LED lamp bars can be driven to work, and the driving capability of the single LED driver is improved. According to the invention, the driving utilization rate of a single LED driver is improved, so that the configuration quantity of the LED drivers is integrally reduced, the problem of complex control algorithm of the MCU caused by controlling a plurality of driving chips to work simultaneously is solved, and the production cost and the design difficulty of the backlight driver are reduced.

It can be understood that the circuit structure of the invention is simple, easy to realize, the local dimming backlight technology can be widely applied to middle and low-end machine equipment, and the development of the local dimming backlight technology is accelerated.

Referring to fig. 1 to 3, in the above embodiment, the LOCAL DIMMING backlight driving circuit includes L LOCAL DIMMING backlight driving branches, and the L LOCAL DIMMING backlight driving branches are arranged in parallel; wherein the content of the first and second substances,

Referring to fig. 3, in the present embodiment, the number of L may be set to 1 or 2, or even more, according to the size of the liquid crystal display device or the number of sets of the backlight module 40. FIG. 3 is a schematic diagram of a circuit structure of a LOCAL DIMMING backlight driving circuit including L LOCAL DIMMING backlight driving branches. In the figure, the LOCAL DIMMING backlight driving branches are denoted as LOCAL DIMMING

backlight driving branches

101 and 102, respectively. It can be understood that the more the number of L, that is, the more the number of the backlight module 40 is, the thinner the backlight area of the liquid crystal display device is, the better the dimming effect is, the better the brightness display effect of each group of lamps is, and the more energy and power can be saved.

Each LOCAL DIMMING backlight driving branch is provided with an LED driver, and a row driving switch and a column driving switch which are driven and controlled based on the LED driver. Sixteen control signal output ends of the LED driver are correspondingly connected with the row driving switches and the column driving switches one by one, namely the total number of the row driving switches and the column driving switches is sixteen. Each LOCAL DIMMING backlight driving branch circuit at least comprises two row driving switches, and when the number of the row driving switches is two, the number of the column driving switches is fourteen; when the number of the row driving switches is three, the number of the column driving switches is thirteen; when the number of the row driving switches is four, the number of the column driving switches is twelve; in addition, in one LOCAL DIMMING backlight driving branch, the number of the row driving switches can be set to eight at most, the number of the column driving switches is also eight, at the moment, the backlight module 40 can be set to eight groups, and the eight groups of backlight modules 40 all comprise eight LED light bars. So set up for a LED driver can drive sixty four LED lamp strips simultaneously, is favorable to improving single LED driver's utilization ratio, has reduced among the LOCAL DIMMING backlight drive device, the holistic configuration quantity of LED driver, thereby reduces backlight drive's manufacturing cost. And the problem that when the MCU controls a plurality of driving chips to work simultaneously, the control algorithm inside the MCU is complex is solved, and the design difficulty of backlight driving is further reduced.

Referring to fig. 1 to 3, in a preferred embodiment, the LOCAL DIMMING backlight driving circuit further includes an MCU, and the MCU is respectively connected to the L LOCAL DIMMING backlight driving branches; the MCU is used for receiving an external control instruction, demodulating a control signal and outputting the demodulated control signal to each LED driver.

In this embodiment, the MCU is a main controller of the backlight driving circuit, and may be implemented by an integrated control chip such as a DSP, an FPGA, a single chip, and the like, and preferably implemented by a single chip, where the single chip is integrated with hardware modules such as an a/D conversion circuit, a comparator, a memory, a data processor, and the like, and a software program and/or module stored in the memory and operable on the data processor, and receives a LOCAL DIMMING signal provided by a timing T-CON board in a liquid crystal display or a main board in the display by operating or executing the software program and/or module stored in the memory, and demodulates the LOCAL DIMMING signal and outputs the demodulated LOCAL DIMMING signal to a corresponding LED driver. It will also be appreciated that in other embodiments, such as in lcd tvs, the MCU may also be implemented using a SOC that outputs a modulated LOCAL DIMMING signal to the LED driver to directly control the operation of the LED driver.

Referring to fig. 1 to 3, in a preferred embodiment, the LOCAL DIMMING backlight driving circuit further includes a communication circuit 50, and the communication circuit 50 is serially disposed between the MCU and the LED driver.

In this embodiment, the communication circuit 50 is preferably an SPI communication interface, and four communication buses of the SPI communication interface are respectively connected to the MCU and the LED driver, so that the MCU and the LED driver are in communication connection, and when the MCU communicates with the LED driver, a LOCAL DIMMING signal after modulation is sent to the LED driver, thereby controlling the LED driver to operate.

Referring to fig. 1 to 3, in a preferred embodiment, the LOCAL DIMMING backlight driving circuit further includes a driving power supply 60, and an output terminal of the driving power supply 60 is connected to input terminals of L × N row driving switches;

the driving power supply 60 is configured to drive the corresponding LED lamp set in the backlight module 40 to operate when the row driving switch corresponding to the L × N row driving switches is closed and the column driving switch corresponding to the L × 16-N column driving switches is closed.

In this embodiment, the driving power supply 60 is configured to convert the accessed driving power supply 60 into a dc power supply, and output the dc power supply to the row driving switches, so that when the corresponding row driving switches are closed row by row and the corresponding column driving switches are closed, the dc power supply is output to the LED light bars corresponding to the row driving switches and the column driving switches, so as to drive the LED light bars to operate. The magnitude of the direct current power output by the driving power supply 60 can be set according to the model specification of the LED lamp strips and the number of the lamp beads on each LED lamp strip.

Referring to fig. 1 to 3, in a preferred embodiment, the LED driver includes a plurality of row driving registers (not shown) and a plurality of column driving registers (not shown), the plurality of row driving registers are used for generating and outputting timing control signals, and the plurality of column driving registers are used for generating and outputting column driving control signals.

In this embodiment, the LED driver sets a corresponding number of registers according to the number of the row driving switches, the number of the column driving switches, and the like, and outputs the generated timing control signal/column driving control signal to the corresponding driving switches, so as to drive the row driving switches and the column driving switches to operate.

Referring to fig. 1 to 3, in a preferred embodiment, the LED driver further includes a current control register (not shown) for generating and outputting a current regulation control signal.

In this embodiment, it can be understood that the LOCAL DIMMING backlight driving circuit is further provided with a current detection circuit, a voltage detection circuit, a temperature detection circuit, an LED protection circuit, and the like, where the current detection circuit, the voltage detection circuit, and the temperature detection circuit are respectively connected to the MCU, and the MCU outputs a corresponding control signal to the LED driver according to detection signals output by the current detection circuit, the voltage detection circuit, and the temperature detection circuit, so that the LED driver generates a corresponding current control signal and outputs the current control signal to a corresponding column driving switch, thereby implementing a protection function for the LED lamp.

The invention also provides a LOCAL DIMMING backlight driving device, which comprises a component B and the LOCAL DIMMING backlight driving circuit. The detailed structure of the LOCAL DIMMING backlight driving circuit can refer to the above embodiments, and is not described herein again; it can be understood that, since the LOCAL DIMMING backlight driving circuit is used in the LOCAL DIMMING backlight driving device of the present invention, the embodiment of the LOCAL DIMMING backlight driving device of the present invention includes all technical solutions of all embodiments of the LOCAL DIMMING backlight driving circuit, and the achieved technical effects are also completely the same, and are not described herein again.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. The LOCAL DIMMING backlight driving circuit is characterized by comprising L LED drivers, L X N row driving switches, L X (16-N) column driving switches and a backlight module, wherein the backlight module comprises L X (16-N) groups of LED light bars, and the number of each group of LED light bars is N; a plurality of control ends of each LED driver are correspondingly connected with controlled ends of N row driving switches and (16-N) column driving switches one by one; the input end of each row driving switch is used for being connected with a direct-current power supply, the output end of each row driving switch is correspondingly connected with one LED lamp strip in the (16-N) group, the cathodes of the LED lamp strips in the (16-N) group are correspondingly connected with the input ends of the (16-N) column driving switches in a one-to-one mode, and the output ends of the column driving switches are grounded; wherein the content of the first and second substances,

the L LED drivers are used for outputting a time sequence control signal according to the number of the row driving switches so as to control the L X N row driving switches to be conducted row by row and outputting a column driving control signal so as to control the L X (16-N) column driving switches to be turned on/off;

l is greater than or equal to 1, N is greater than or equal to 2 and less than or equal to 8;

the LOCAL DIMMING backlight driving circuit comprises L LOCAL DIMMING backlight driving branches, and the L LOCAL DIMMING backlight driving branches are arranged in parallel; wherein the content of the first and second substances,

2. The LOCAL DIMMING backlight driver circuit of claim 1, further comprising a MCU, wherein the MCU is respectively connected to the L LOCAL DIMMING backlight driving branches; the MCU is used for receiving an external control instruction, demodulating a control signal and outputting the demodulated control signal to each LED driver.

3. The LOCAL DIMMING backlight driver circuit of claim 2, further comprising a communication circuit disposed in series between the MCU and the LED driver.

4. The LOCAL DIMMING backlight driver circuit of claim 1, further comprising a drive power supply, an output of said drive power supply being connected to L x N of said row drive switch inputs;

5. The LOCAL DIMMING backlight driver circuit according to any one of claims 1-4, wherein the LED driver comprises a plurality of row driving registers for generating and outputting timing control signals and a plurality of column driving registers for generating and outputting column driving control signals.

6. The LOCAL DIMMING backlight driver circuit of claim 5, wherein the LED driver further comprises a current control register for generating and outputting a current adjustment control signal.

7. A LOCAL DIMMING backlight driver comprising the LOCAL DIMMING backlight driver circuit as claimed in any one of claims 1 to 6.

8. A liquid crystal display device comprising the LOCAL DIMMING backlight driving apparatus as claimed in claim 7.