Redundant light bar driving circuit and method

Abstract

The present invention is applicable to the field of light bar driving technology, and provides a redundant light bar driving circuit and method, the redundant light bar driving circuit includes: a power conversion circuit; a backlight driving controller; a light bar switch switching circuit; a current back-testing circuit; and a dual redundant light group connected to the power conversion circuit, the light bar switch switching circuit, and the current back-testing circuit, respectively, the dual redundant light group can be controlled to switch; the power conversion circuit is respectively connected to the backlight driving controller, the light bar switch switching circuit, and the current back-testing circuit, and the light bar switch switching circuit and the current back-testing circuit are respectively connected to the backlight driving controller. The present invention solves the problems of low reliability and low life of the liquid crystal screen in the prior art, thereby achieving high reliability and long life of the liquid crystal screen.

Description

Technical Field

[0001] The present invention belongs to the technical field of light bar driving, and in particular relates to a redundant light bar driving circuit and method. Background Art

[0002] With the development of smart cities, outdoor high-brightness display devices are increasingly widely used, and the most widely used are high-resolution, large-size LCD screens. Since the outdoor ambient light brightness is very high, the LCD screen needs very high power to drive the backlight in order to achieve high brightness, which results in very high power density and temperature rise of the backlight strip. Thousands of lamp beads will be used in a large-screen LCD screen. As long as one is damaged, a black bar will appear on the LCD screen. Therefore, how to achieve high reliability and long life brings great challenges. It can be seen that the existing LCD screen has the problems of low reliability and low life. Summary of the invention

[0003] The embodiment of the present invention provides a redundant light bar driving circuit, aiming to solve the problems of low reliability and short life of liquid crystal screens in the prior art.

[0004] An embodiment of the present invention provides a redundant light bar driving circuit, comprising: a power conversion circuit; a backlight driving controller; a light bar switch switching circuit; a current back-testing circuit; and a dual redundant light group respectively connected to the power conversion circuit, the light bar switch switching circuit, and the current back-testing circuit, wherein the dual redundant light group can be controlled to switch; the power conversion circuit is respectively connected to the backlight driving controller, the light bar switch switching circuit, and the current back-testing circuit, and the light bar switch switching circuit and the current back-testing circuit are respectively connected to the backlight driving controller.

[0005] Furthermore, the dual redundant light group includes: a first redundant light bar, and a second redundant light bar; the positive pole of the first redundant light bar is connected to the power conversion circuit, and the negative pole of the first redundant light bar is connected to the light bar switch switching circuit; the positive pole of the second redundant light bar is arranged on the connecting line between the positive pole of the first redundant light bar and the power conversion circuit, and the negative pole of the second redundant light bar is connected to the current feedback circuit.

[0006] Furthermore, the power conversion circuit is connected to the backlight driving controller via a lamp group driving current signal;

[0007] The light bar switch switching circuit is connected to the backlight driving controller through a first light bar enable signal and a first back-test current signal, and the first light bar enable signal and the first back-test current signal correspond to the first redundant light bar;

[0008] The current back-testing circuit is connected to the backlight driving controller via a second light bar enable signal and a second back-testing current signal, and the second light bar enable signal and the second back-testing current signal correspond to the second redundant light bar.

[0009] Furthermore, the backlight driving controller is an ARM processor.

[0010] Furthermore, the power conversion circuit includes: a DCDC converter.

[0011] An embodiment of the present invention provides a redundant light bar driving method, which is used in the redundant light bar driving circuit provided in the above embodiment. The redundant light bar driving method includes the following steps:

[0012] When a power signal is detected, the backlight driving constant current value is adjusted and output to the power conversion circuit;

[0013] Turning on each dual redundant light group according to the backlight driving constant current value and the enable signal; the enable signal corresponds to the dual redundant light group, and the enable signal includes a first light bar enable signal for controlling the first redundant light bar and a second light bar enable signal for controlling the second redundant light bar;

[0014] Detecting the current value of each dual redundant lamp group;

[0015] Determine whether the dual redundant lamp group has a fault according to the current value of the dual redundant lamp group and the constant current value of the backlight drive;

[0016] If there is a fault, the dual redundant light groups are switched and controlled.

[0017] Furthermore, the step of detecting the current value of each dual redundant lamp group includes:

[0018] Detecting a first back-test current signal of a first redundant light bar and converting the signal into a first back-test current value;

[0019] Detecting a second back-test current signal of the second redundant light bar and converting the signal into a second back-test current value;

[0020] Wherein, under normal circumstances, the first back-test current value is the same as the second back-test current value, and the sum of the first back-test current value and the second back-test current value is equal to the backlight driving constant current value.

[0021] Furthermore, the step of judging whether the dual redundant lamp group has a fault according to the current value of the dual redundant lamp group and the backlight driving constant current value includes:

[0022] summing the first back-measured current value and the second back-measured current value;

[0023] If the sum of the first back-measured current value and the second back-measured current value is not equal to the backlight driving constant current value, it is determined that the dual redundant lamp group has a fault.

[0024] Furthermore, if the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, the step of determining that the dual redundant lamp group has a fault includes:

[0025] Preset a preset current value. Under normal circumstances, the preset current value of the first back-test current value is equal to the preset current value of the second back-test current value, and the sum of the preset current value of the first back-test current value and the preset current value of the second back-test current value is equal to the backlight driving constant current value;

[0026] If the first back-test current value is lower than the preset current value, the second back-test current value is lower than the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that both the first redundant light bar and the second redundant light bar in the dual redundant light group are faulty;

[0027] If the first back-test current value is lower than the preset current value, the second back-test current value is equal to the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that the first redundant light bar in the dual redundant light group fails;

[0028] Alternatively, if the first back-test current value is equal to the preset current value and the second back-test current value is lower than the preset current value, then the sum of the first back-test current value and the second back-test current value is not equal to the backlight drive constant current value, then it is determined that the second redundant light bar in the dual redundant light group is faulty.

[0029] Furthermore, if there is a fault, the step of switching and controlling the dual redundant light set includes:

[0030] If both the first redundant light bar and the second redundant light bar in the dual redundant light group fail, performing odd-even switching control of the entire screen dual redundant light group;

[0031] If the first redundant light bar in the dual redundant light group fails, performing odd-even switching control of the first redundant light bar in the adjacent dual redundant light group;

[0032] Alternatively, if the second redundant light bar in the dual redundant light group fails, odd-even switching control of the second redundant light bar in the adjacent dual redundant light group is performed.

[0033] The beneficial effects achieved by the present invention are as follows: the present invention adopts a power conversion circuit; a backlight drive controller; a light bar switch switching circuit; a current back-testing circuit; and a dual redundant light group connected to the power conversion circuit, the light bar switch switching circuit, and the current back-testing circuit respectively to cooperate and control the driving of the dual redundant light group. When a dual redundant light group fails, it can realize redundant light bar backup, fault detection, and automatically switch the faulty light bar to the backup light bar, allowing the backlight to be driven to maintain the LCD display even when half of the light bars are damaged. The present invention solves the problems of low reliability and low life of the LCD screen in the prior art, thereby achieving high reliability and long life of the LCD screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a structural schematic diagram of a redundant light bar driving circuit provided by an embodiment of the present invention;

[0035] Figure 2 It is a schematic flow chart of a redundant light bar driving method provided by an embodiment of the present invention.

[0036] Among them, 1. backlight drive controller; 2. power conversion circuit; 3. first redundant light bar; 4. second redundant light bar; 5. dual redundant light group; 6. light bar switch switching circuit; 7. current back-test circuit. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] like Figure 1 As shown, Figure 1 It is a structural schematic diagram of a redundant light bar driving circuit provided by an embodiment of the present invention; the redundant light bar driving circuit includes: a power conversion circuit 2; a backlight driving controller 1; a light bar switch switching circuit 6; a current back-testing circuit 7; and a dual redundant light group 5 respectively connected to the power conversion circuit 2, the light bar switch switching circuit 6, and the current back-testing circuit 7, and the dual redundant light group 5 can be controlled to switch; the power conversion circuit 2 is respectively connected to the backlight driving controller 1, the light bar switch switching circuit 6, and the current back-testing circuit 7, and the light bar switch switching circuit 6 and the current back-testing circuit 7 are respectively connected to the backlight driving controller 1.

[0039] Furthermore, the backlight driving controller 1 is an ARM processor; the power conversion circuit 2 includes: a DCDC converter; the light bar switch switching circuit 6 includes a SWITCH switch 1; and the current back-testing circuit 7 includes a SWITCH switch 2.

[0040] Furthermore, the dual redundant light group 5 includes: a first redundant light strip 3, and a second redundant light strip 4; the positive pole of the first redundant light strip 3 is connected to the power conversion circuit 2, and the negative pole of the first redundant light strip 3 is connected to the light strip switch switching circuit 6; the positive pole of the second redundant light strip 4 is arranged on the connecting line between the positive pole of the first redundant light strip 3 and the power conversion circuit 2, and the negative pole of the second redundant light strip 4 is connected to the current feedback circuit 7.

[0041] Furthermore, the power conversion circuit 2 is connected to the backlight driving controller 1 through the lamp group driving current signal. The light bar switch switching circuit 6 is connected to the backlight driving controller 1 through the first light bar enable signal and the first back-test current signal, and the first light bar enable signal and the first back-test current signal correspond to the first redundant light bar 3. The current back-test circuit 7 is connected to the backlight driving controller 1 through the second light bar enable signal and the second back-test current signal, and the second light bar enable signal and the second back-test current signal correspond to the second redundant light bar 4.

[0042] Among them, the above-mentioned dual redundant light group 5 can be a dual redundant LED light group, the above-mentioned first redundant light strip 3 can be a first redundant LED light strip, the first redundant LED light strip includes LED light one, and the above-mentioned second redundant light strip 4 can be a second redundant LED light strip, the second redundant LED light strip includes LED light two.

[0043] The ARM processor includes: pin LED-DIM, used to output the backlight drive constant current signal; pin GND, used for grounding; pin LED-EN1, used to output the first light bar enable signal; pin LED-IFB1, used to receive the first back-test current signal; pin LED-EN2, used to output the second light bar enable signal; pin LED-IFB2, used to receive the second back-test current signal. Functional modules for controlling the corresponding functions of each pin are set in the ARM processor.

[0044] The above-mentioned DCDC converter includes: pin VIN, used to connect to the power supply; pin GND, used to connect to the ground; pin DIM, used to receive the backlight driving constant current signal transmitted by the pin LED-DIM; pin VLED+, used to output the backlight driving constant current signal to control the dual redundant light group 5, specifically, used to connect the positive pole of the first redundant light bar 3 and the positive pole of the second redundant light bar 4; pin VLED-, used to connect SWITCH switch 1 and SWITCH switch 2 respectively. The DCDC converter is provided with a functional module for controlling the corresponding function of each pin.

[0045] The above-mentioned SWITCH switch 1 includes: pin GND, used for grounding; pin LED-EN, used for receiving the first light bar enable signal output by pin LED-EN1 in the ARM processor; pin I-LED, used for outputting the first return current signal of the first redundant light bar 3 to pin LED-IFB1 in the ARM processor; pin VLED+, used for connecting pin VLED- in the DCDC converter to form a loop; pin LED-K-, used for connecting the negative pole of the first redundant light bar 3 to form a loop.

[0046] The above-mentioned SWITCH switch 2 includes: pin GND, used for grounding; pin LED-EN, used for receiving the second light bar enable signal output by pin LED-EN2 in the ARM processor; pin I-LED, used for outputting the second back-test current signal of the second redundant light bar 4 to pin LED-IFB2 in the ARM processor; pin VLED+, used for connecting pin VLED- in the DCDC converter to form a loop; pin LED-K-, used for connecting the negative pole of the second redundant light bar 4 to form a loop.

[0047] In the embodiment of the present invention, the present invention adopts a power conversion circuit 2; a backlight drive controller 1; a light bar switch switching circuit 6; a current back-testing circuit 7; and a dual redundant light group 5 respectively connected to the power conversion circuit 2, the light bar switch switching circuit 6, and the current back-testing circuit 7 to cooperate and control the driving of the dual redundant light group 5. When the dual redundant light group 5 fails, it can realize redundant light bar backup, fault detection, and automatically switch the faulty light bar to the backup light bar, allowing the backlight to be driven to maintain the LCD display even when half of the light bars are damaged. The present invention solves the problems of low reliability and low life of the LCD screen in the prior art, thereby achieving high reliability and long life of the LCD screen.

[0048] like Figure 2 As shown, Figure 2 The present invention provides a flow chart of a redundant light bar driving method, which is used in the redundant light bar driving circuit provided in the above embodiment. The redundant light bar driving method includes the following steps:

[0049] S101, when a power signal is detected, adjusting the backlight driving constant current value and outputting it to the power conversion circuit.

[0050] S102, turning on each dual redundant light group according to the backlight driving constant current value and the enable signal; the enable signal corresponds to the dual redundant light group, and the enable signal includes a first light bar enable signal for controlling the first redundant light bar and a second light bar enable signal for controlling the second redundant light bar.

[0051] S103, detecting the current value of each dual redundant lamp group.

[0052] S104, judging whether the dual redundant lamp group 5 has a fault according to the dual redundant lamp group current value and the backlight driving constant current value.

[0053] S105: If there is a fault, switch control of the dual redundant light groups.

[0054] Specifically, the volt-ampere characteristic of LED is a positive coefficient, that is, as the current of LED increases, the voltage drop will also increase. Since the redundant light strip in the present invention adopts dual redundancy, the total backlight driving current of the power conversion circuit can be kept constant, and the logic of driving the first redundant LED light strip and the second redundant LED2 light strip to light up at the same time can be adopted. At this time, the brightness is basically the same as when a single light strip is lit, but the current of each redundant LED light strip is halved, and the voltage drop of the redundant LED light strip is smaller. Almost 80% of the power of the LED lights in the redundant LED light strip is heating, so after reducing the voltage, the direct effect is that the heat generation is effectively reduced and the temperature rise is smaller; and the life of the LED lamp is inversely proportional to the temperature, and because all LEDs are lit at the same time, the thermal resistance is smaller, the heat dissipation is better, and the total temperature rise will also be smaller. The industry's rough estimate is that for every 10 degrees reduction in LED junction temperature, the life span increases by about 2 times; and because of the use of dual redundant light groups, the redundant light strips are doubled, and the number of LED lamp beads is also doubled, so the total life span can theoretically be extended by more than 2 times.

[0055] Furthermore, the total LED backlight drive current of the power conversion circuit is controlled by the LED-DIM signal (backlight drive constant current signal) in the back ARM processor, and the power current output of the power conversion circuit is output by VLED+ and returned by VLED-. The sum of the first backtest current and the second backtest current of the loop current backtest of the first redundant light bar and the second redundant light bar is equal to the total output current of the power conversion circuit, that is, the sum of the first backtest current value and the second backtest current value is equal to the backlight drive constant current value of the power conversion circuit. Since the light bar adopts exactly the same lamp bead welding method and is located in adjacent positions, the first backtest current value and the second backtest current value are almost the same during normal operation. Since the failure mode of the high-brightness LED is open circuit, the first backtest current value, the second backtest current value or the absolute value and relative value can be used to determine whether the light bar has a failure fault. When a fault occurs, the backlight drive controller can perform redundant switching of the first redundant light bar and the second redundant light bar through the first light bar enable signal and the second light bar enable signal.

[0056] Since LCD screens generally use dozens of redundant light strips, in order to achieve the longest life and the highest redundancy, there must be an optimal switching logic. Under normal circumstances, all light strips are driven and lit, and the light effect is uniform, the heat is minimal, and the life is longest; when a single light strip fails, that is, when the light group fails, the whole screen light group is switched to odd and even (for example, if a light group in the odd group fails, all odd group light groups are turned off and the even group light groups are turned on), and the screen brightness is still perfectly consistent; when a light strip in a light group fails, the adjacent groups of odd and even light strips are switched. Since the arrangement of the lamp beads is specially designed, the screen brightness difference is very small at this time, and there is no obvious difference. At this time, at most half of the light strips on the entire screen can fail, and the display can still be basically normal, and the redundancy is maximum at this time.

[0057] The present invention adopts a group of power driving power supplies to simultaneously drive two light strips in the redundant light group. Therefore, compared with the non-redundant driving circuit, the power driving part of the entire circuit design is the same, and only the current detection circuit and the number of light strips are increased. Therefore, the redundancy function can be achieved with the lowest cost and board area. In addition, the lamp beads of the first redundant light strip and the second redundant light strip are lit at the same time at normal times, and the whole screen or a single group of light strips are switched in case of failure. Therefore, it is allowed to work normally even if half of the light strips are damaged.

[0058] Since the constant current driving power supply of the redundant light strips uses the same group, even if the redundant detection circuit switches incorrectly, since the driving current of the constant current driving power supply is a constant value, it will not cause electrical overstress overload and other situations in the circuit components, and the circuit will still be safe and not damaged, so it has high safety and reliability.

[0059] In terms of LED life, since all LED light strips are lit at the same time, the current of each lamp bead is halved, so the LED lamp bead has lower tube voltage drop and heat generation, less light decay, and longer life, achieving the purpose of extending the life.

[0060] In addition to adopting the basic control strategy of increasing the life of LEDs by lowering the junction temperature, the present invention also adopts a dual redundant driving and detection circuit, which can still work normally when a light bar fails. This will greatly increase the effective life of outdoor displays, has good self-repair characteristics, and can generate greater economic value.

[0061] Furthermore, S103 includes:

[0062] A first back-test current signal of the first redundant light bar is detected and converted into a first back-test current value.

[0063] A second back-test current signal of the second redundant light bar is detected and converted into a second back-test current value.

[0064] In a normal situation, the first back-test current value is the same as the second back-test current value, and the sum of the first back-test current value and the second back-test current value is equal to the backlight driving constant current value.

[0065] Furthermore, S104 includes:

[0066] The first back-measured current value and the second back-measured current value are summed.

[0067] If the sum of the first back-measured current value and the second back-measured current value is not equal to the backlight driving constant current value, it is determined that the dual redundant lamp set 5 has a fault.

[0068] Furthermore, if the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, the step of determining whether the dual redundant lamp group 5 is faulty includes:

[0069] A preset current value is preset. Under normal circumstances, the preset current value of the first back-test current value is equal to the preset current value of the second back-test current value, and the sum of the preset current value of the first back-test current value and the preset current value of the second back-test current value is equal to the backlight driving constant current value.

[0070] If the first back-test current value is lower than the preset current value, and the second back-test current value is lower than the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that both the first redundant light bar and the second redundant light bar in the dual redundant light group are faulty.

[0071] If the first back-test current value is lower than the preset current value and the second back-test current value is equal to the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that the first redundant light bar in the dual redundant light group fails.

[0072] Alternatively, if the first back-test current value is equal to the preset current value and the second back-test current value is lower than the preset current value, the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, then it is determined that the second redundant light bar in the dual redundant light group is faulty.

[0073] Furthermore, if there is a fault, the steps of switching and controlling the dual redundant light groups include:

[0074] If both the first redundant light bar and the second redundant light bar in the dual redundant light group fail, the odd-even switching control of the dual redundant light group of the entire screen is performed.

[0075] If a first redundant light bar in a dual redundant light group fails, odd-even switching control of the first redundant light bar in an adjacent dual redundant light group is performed.

[0076] Alternatively, if a second redundant light bar in a dual redundant light group fails, odd-even switching control of the second redundant light bar in an adjacent dual redundant light group is performed.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A redundant light bar driving circuit, characterized in that: include: Power conversion circuit; Backlight drive controller; light bar switch circuit; Current back-test circuit; and a dual redundant lamp group respectively connected to the power conversion circuit, the light bar switch switching circuit, and the current back-testing circuit, wherein the dual redundant lamp group can be controlled to switch; the power conversion circuit is respectively connected to the backlight driving controller, the light bar switch switching circuit, and the current back-testing circuit, and the light bar switch switching circuit and the current back-testing circuit are respectively connected to the backlight driving controller; The dual redundant light set includes: a first redundant light bar and a second redundant light bar; the positive pole of the first redundant light bar is connected to the power conversion circuit, and the negative pole of the first redundant light bar is connected to the light bar switch switching circuit; the positive pole of the second redundant light bar is arranged on the connection line between the positive pole of the first redundant light bar and the power conversion circuit, and the negative pole of the second redundant light bar is connected to the current back-testing circuit; The power conversion circuit is connected to the backlight driving controller via a lamp group driving current signal; The light bar switch switching circuit is connected to the backlight driving controller through a first light bar enable signal and a first back-test current signal, and the first light bar enable signal and the first back-test current signal correspond to the first redundant light bar; The current back-test circuit is connected to the backlight driving controller via a second light bar enable signal and a second back-test current signal, and the second light bar enable signal and the second back-test current signal correspond to the second redundant light bar; The backlight drive controller is an ARM processor; The redundant light bar driving method comprises the following steps: When a power signal is detected, the backlight driving constant current value is adjusted and output to the power conversion circuit; Turning on each dual redundant light group according to the backlight driving constant current value and the enable signal; the enable signal corresponds to the dual redundant light group, and the enable signal includes a first light bar enable signal for controlling the first redundant light bar and a second light bar enable signal for controlling the second redundant light bar; Detecting the current value of each dual redundant lamp group; Determining whether the dual redundant lamp group has a fault according to the current value of the dual redundant lamp group and the constant current value of the backlight drive; If there is a fault, the dual redundant light groups are switched and controlled; The steps of detecting the current value of each dual redundant lamp group include: Detecting a first back-test current signal of a first redundant light bar and converting the signal into a first back-test current value; Detecting a second back-test current signal of the second redundant light bar and converting the signal into a second back-test current value; Wherein, under normal circumstances, the first back-test current value is the same as the second back-test current value, and the sum of the first back-test current value and the second back-test current value is equal to the backlight driving constant current value; If the sum of the first back-measured current value and the second back-measured current value is not equal to the backlight driving constant current value, the step of determining whether the dual redundant lamp group has a fault includes: Preset a preset current value. Under normal circumstances, the preset current value of the first back-test current value is equal to the preset current value of the second back-test current value, and the sum of the preset current value of the first back-test current value and the preset current value of the second back-test current value is equal to the backlight driving constant current value; If the first back-test current value is lower than the preset current value, the second back-test current value is lower than the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that both the first redundant light bar and the second redundant light bar in the dual redundant light group are faulty; If the first back-test current value is lower than the preset current value, the second back-test current value is equal to the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that the first redundant light bar in the dual redundant light group fails; Alternatively, if the first back-test current value is equal to the preset current value, and the second back-test current value is lower than the preset current value, and the sum of the first back-test current value and the second back-test current value is not equal to the backlight driving constant current value, it is determined that the second redundant light bar in the dual redundant light group is faulty; If there is a fault, the steps of switching and controlling the dual redundant light group include: If both the first redundant light bar and the second redundant light bar in the dual redundant light group fail, performing odd-even switching control of the full-screen dual redundant light group; If the first redundant light bar in the dual redundant light group fails, performing odd-even switching control of the first redundant light bar in the adjacent dual redundant light group; Alternatively, if the second redundant light bar in the dual redundant light group fails, odd-even switching control of the second redundant light bar in the adjacent dual redundant light group is performed.

2. The redundant light bar driving circuit according to claim 1, characterized in that: The power conversion circuit includes: a DCDC converter.

3. The redundant light bar driving circuit according to claim 1, characterized in that: The step of judging whether the dual redundant lamp group has a fault according to the current value of the dual redundant lamp group and the constant current value of the backlight drive comprises: summing the first back-measured current value and the second back-measured current value; If the sum of the first back-measured current value and the second back-measured current value is not equal to the backlight driving constant current value, it is determined that the dual redundant lamp group has a fault.

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