Backlight source driving circuit, driving method and display screen

Abstract

The invention provides a backlight source driving circuit, a driving method and a display screen, and a control unit is used for outputting a PWM signal, controlling a pixel array through the PWM signal, and sending communication information to a driving unit; wherein the number of the PWM signals is X, X is smaller than or equal to N, and the initial phases of the X PWM signals are sequentially delayed by a preset period; the driving unit is used for generating M control signals according to the communication information and controlling the pixel array through the M control signals; wherein M, N and X are all positive integers. The control unit can output the X PWM signals with the initial phases sequentially delayed by the preset period and send the PWM signals to the first end of the pixel array to control the pixel array, so that only the pixel units with the number smaller than N in the pixel array can be driven at the same time instead of driving the N pixel units at the same time, and the driving efficiency is improved. Therefore, the impact current generated when the backlight drive circuit drives the pixel array can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of backlight source driving, and in particular to a backlight source driving circuit, a driving method and a display screen. Background Art

[0002] With respect to the current backlight driving technology, taking driving a pixel array of 4 rows and 16 columns as an example, a common control scheme is row-by-row driving, that is, driving the pixel units of each row and 16 columns in sequence.

[0003] Taking the 4*16 matrix Mini-LED backlight circuit as an example, the common control scheme currently uses one 8-channel driver chip to control the anode of Mini-LED, and two 8-channel driver chips to control the cathode of Mini-LED. When in use, the first to fourth rows are lit up in sequence through a time-sharing scanning scheme. Due to the influence of the parasitic inductance of Mini-LED, when multiple Mini-LEDs are switched on and off at the same time, a large impact current will be generated, affecting the stability of the system and reducing the service life of Mini-LED. In addition, the production cost of the backlight driver circuit is relatively high. Summary of the invention

[0004] The embodiments of the present application provide a backlight driving circuit, a driving method and a display screen, which are used to reduce the impact current generated by the backlight driving circuit when driving a pixel array.

[0005] In a first aspect, an embodiment of the present application provides a backlight source driving circuit, which is applied to a pixel array of M rows and N columns, including: a control unit and a driving unit;

[0006] The control unit is connected to the first end of the pixel array and the driving unit respectively; the driving unit is also connected to the second end of the pixel array;

[0007] The control unit is used to output a PWM signal, control the pixel array through the PWM signal, and send communication information to the driving unit; wherein the PWM signal is X, X is less than or equal to N, and the initial phases of the X PWM signals are delayed by a preset period in sequence;

[0008] The driving unit is used to generate M control signals according to the communication information, and control the pixel array through the M control signals; wherein M, N, and X are all positive integers.

[0009] In some embodiments, the driving unit includes a driving chip and M switch subunits;

[0010] The SPI interface end of the driving chip is connected to the SPI interface end of the control unit; the M first signal output ends of the driving chip are respectively connected to the control ends of the M switch subunits, the M second signal output ends of the driving chip are respectively connected to the first ends of the M switch subunits, and the M second signal output ends of the driving chip are also respectively connected to the second ends of the pixel array; the second ends of the M switch subunits are respectively connected to the power supply end;

[0011] The driving chip is used to receive the communication information sent by the control unit, generate M first pulse signals and M second pulse signals according to the communication information, and send the M first pulse signals and the M second pulse signals to the M switch sub-units;

[0012] The M switch sub-units are used to generate the M control signals according to the M first pulse signals and the M second pulse signals, and control the pixel array through the M control signals.

[0013] In some embodiments, the control unit is further used to send a synchronization signal to the driving chip so that the PWM signal output by the control unit is synchronized with the output time of the M first pulse signals and the M second pulse signals generated by the driving chip.

[0014] In some embodiments, the M switch subunits include M switch tubes;

[0015] The control ends of the M switch tubes serve as the control ends of the M switch sub-units, the first ends of the M switch tubes serve as the first ends of the M switch sub-units, and the second ends of the M switch tubes serve as the second ends of the M switch sub-units.

[0016] In some embodiments, the M switch tubes are all MOS tubes;

[0017] The gates of the M MOS tubes serve as the control ends of the M switch tubes, the drains of the M MOS tubes serve as the first ends of the M switch tubes, and the sources of the M MOS tubes serve as the second ends of the M switch tubes; or

[0018] The gates of the M MOS tubes serve as control ends of the M switch tubes, the sources of the M MOS tubes serve as first ends of the M switch tubes, and the drains of the M MOS tubes serve as second ends of the M switch tubes.

[0019] In some embodiments, an isolation chip is also included;

[0020] The control unit is connected to the first end of the pixel array through the isolation chip;

[0021] The isolation chip is used to perform signal isolation between the first end of the pixel array and the control unit.

[0022] In some embodiments, each pixel unit of the pixel array is an LED lamp;

[0023] The cathodes of the M*N LED lamps serve as the first end of the pixel array, and the anodes of the M*N LED lamps serve as the second end of the pixel array;

[0024] The control unit is further used to output a PWM signal, control the LED lights in the pixel array through the PWM signal, and send communication information to the driving unit;

[0025] The driving unit is further used to generate M control signals according to the communication information, and control the M*N LED lights in the pixel array through the M control signals.

[0026] In some embodiments, the M switch sub-units are further used to generate M control signals according to the M first pulse signals and the M second pulse signals, and control the M*N LED lights in the pixel array through the M control signals.

[0027] In a second aspect, the embodiment of the present application further provides a backlight source driving method, comprising:

[0028] The control unit outputs a PWM signal, controls the pixel array through the PWM signal, and sends communication information to the driving unit; wherein the number of the PWM signals is X, X is less than or equal to N, and the initial phases of the X PWM signals are sequentially delayed by a preset period;

[0029] The driving unit generates M control signals according to the communication information, and controls the pixel array through the M control signals; wherein M, N, and X are all positive integers.

[0030] In a third aspect, an embodiment of the present application further provides a display screen, comprising a pixel array of M rows and N columns and a backlight source driving circuit as described in any one of the first aspects.

[0031] The embodiment of the present application provides a backlight driving circuit, a driving method and a display screen, the backlight driving circuit is applied to a pixel array of M rows and N columns, and includes a control unit and a driving unit; the control unit is connected to the first end of the pixel array and the driving unit respectively; the driving unit is also connected to the second end of the pixel array; the control unit is used to output a PWM signal, control the pixel array through the PWM signal, and send communication information to the driving unit; wherein the PWM signal is X, X is less than or equal to N, and the initial phases of the X PWM signals are sequentially delayed by a preset period; the driving unit is used to generate M control signals according to the communication information, and control the pixel array through the M control signals; wherein M, N, and X are all positive integers. Since the control unit can output X PWM signals with initial phases sequentially delayed by a preset period, and send the PWM signal to the first end of the pixel array to control the pixel array, it is possible to drive only the pixel units less than N in the pixel array at the same time, instead of driving N pixel units at the same time, thereby reducing the impact current generated by the backlight driving circuit when driving the pixel array. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of the structure of a backlight source driving circuit provided in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of another backlight source driving circuit provided in an embodiment of the present application;

[0035] Figure 3 A schematic diagram of the structure of another backlight source driving circuit provided in an embodiment of the present application;

[0036] Figure 4 A schematic diagram of the structure of another backlight source driving circuit provided in an embodiment of the present application;

[0037] Figure 5 A schematic diagram of the structure of another backlight source driving circuit provided in an embodiment of the present application;

[0038] Figure 6 A schematic diagram of the structure of another backlight source driving circuit provided in an embodiment of the present application;

[0039] Figure 7 A schematic diagram of a 4*16 matrix Mini-LED backlight source circuit provided in an embodiment of the present application;

[0040] Figure 8 A schematic diagram of a 4*16 matrix Mini-LED backlight source driving circuit provided in an embodiment of the present application;

[0041] Fig. 9 A waveform diagram of a driver chip output provided in an embodiment of the present application;

[0042] Fig.10 A waveform diagram of an MCU output provided in an embodiment of the present application;

[0043] Fig.11 A schematic diagram of a Mini-LED working waveform provided in an embodiment of the present application;

[0044] Fig.12 A schematic flow chart of a backlight source driving method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0046] In order to reduce the impact current generated by the backlight driving circuit when driving the pixel array, the embodiment of the present application provides a backlight driving circuit, which is applied to the pixel array of M rows and N columns, such as Figure 1 As shown, the backlight source driving circuit includes: a control unit 101 and a driving unit 102;

[0047] The control unit 101 is connected to the first end of the pixel array and the driving unit 102 respectively; the driving unit 102 is also connected to the second end of the pixel array;

[0048] The control unit 101 is used to output a PWM signal, control the pixel array through the PWM signal, and send communication information to the driving unit 102; wherein the PWM signal is X, X is less than or equal to N, and the initial phases of the X PWM signals are delayed by a preset period in sequence;

[0049] The driving unit 102 is used to generate M control signals according to the communication information, and control the pixel array through the M control signals; wherein M, N, and X are all positive integers.

[0050] It is worth noting that each pixel unit in the pixel array is controlled by a PWM signal and a control signal at the same time. Only when the levels of the PWM signal and the control signal meet the preset conditions can the corresponding pixel unit be driven successfully.

[0051] The backlight source driving circuit provided in the embodiment of the present application has a control unit that can output PWM signals with X initial phases sequentially delayed by a preset period, and send the PWM signals to the first end of the pixel array to control the pixel array. Therefore, only pixel units less than N in the pixel array can be driven at the same time, rather than driving N pixel units at the same time, thereby reducing the impact current generated by the backlight source driving circuit when driving the pixel array.

[0052] In the specific implementation, Figure 2 As shown, the control unit 101 may be a micro control unit 101 (Micro Control Unit, MCU), and the driving unit 102 may include a driving chip 1021 and M switch subunits 1022;

[0053] The SPI interface end of the driving chip 1021 is connected to the SPI interface end of the control unit 101; the M first signal output ends of the driving chip 1021 are respectively connected to the control ends of the M switch subunits 1022, the M second signal output ends of the driving chip 1021 are respectively connected to the first ends of the M switch subunits 1022, and the M second signal output ends of the driving chip 1021 are also respectively connected to the second ends of the pixel array; the second ends of the M switch subunits 1022 are respectively connected to the power supply end VCC;

[0054] The driving chip 1021 is used to receive the communication information sent by the control unit 101, generate M first pulse signals and M second pulse signals according to the communication information, and send the M first pulse signals and the M second pulse signals to the M switch sub-units 1022;

[0055] The M switch sub-units 1022 are used to generate M control signals according to the M first pulse signals and the M second pulse signals, and control the pixel array through the M control signals.

[0056] The above structure uses only one driver chip, which is lower in cost than the circuit structure using three driver chips in the prior art.

[0057] In the specific implementation, Figure 3As shown, the SPI interface may specifically include three interfaces: CLK, MOSI, and MISO. The MCU communicates with the driver chip 1021 through these three interfaces. In the embodiment of the present application, the MCU acts as a host and sends communication information to the driver chip 1021 through the MOSI interface. The communication information can be parsed by the driver chip 1021, so that the driver chip 1021 outputs a first pulse signal and a second pulse signal, and generates a control signal based on the first pulse signal and the second pulse signal.

[0058] In the specific implementation, Figure 4 As shown, the control unit 101 is also used to send a synchronization signal VSYN to the driving chip 1021 to synchronize the output time of the PWM signal output by the control unit 101 with the output time of the M first pulse signals and the M second pulse signals generated by the driving chip 1021 to avoid disorder in the output signal timing.

[0059] In the specific implementation, Figure 5 As shown, the backlight source driving circuit may further include an isolation chip; the control unit 101 is connected to the first end of the pixel array via the isolation chip;

[0060] The isolation chip is used to perform signal isolation between the first end of the pixel array and the control unit 101, thereby avoiding damage to the control unit 101, that is, avoiding damage to the MCU.

[0061] In the specific implementation, Figure 6 As shown, the M switch subunits 1022 may include M switch tubes;

[0062] The control ends of the M switch tubes serve as the control ends of the M switch sub-units 1022 , the first ends of the M switch tubes serve as the first ends of the M switch sub-units 1022 , and the second ends of the M switch tubes serve as the second ends of the M switch sub-units 1022 .

[0063] Specifically, the M switch tubes may all be MOS tubes, and may be PMOS tubes or NMOS tubes;

[0064] The gates of the M MOS tubes serve as the control terminals of the M switch tubes, the drains of the M MOS tubes serve as the first terminals of the M switch tubes, and the sources of the M MOS tubes serve as the second terminals of the M switch tubes; or

[0065] The gates of the M MOS tubes serve as control terminals of the M switch tubes, the sources of the M MOS tubes serve as first terminals of the M switch tubes, and the drains of the M MOS tubes serve as second terminals of the M switch tubes.

[0066] For ease of understanding, the following description is given by assuming that each pixel unit of the pixel array is an LED lamp.

[0067] Mini-LED is used as a backlight source, which mainly refers to the combination of Mini-LED and LCD (liquid crystal) display to realize the display product of "Mini-LED backlight + LCD". Compared with traditional LED backlight LCD, Mini-LED backlight has the characteristics of high color gamut, wide viewing angle, low power consumption, ultra-thin and energy-saving.

[0068] When each pixel unit of the pixel array is an LED lamp, the cathodes of the M*N LED lamps serve as the first end of the pixel array, and the anodes of the M*N LEDs serve as the second end of the pixel array;

[0069] The control unit 101 is further used to output a PWM signal, control the LED lights in the pixel array through the PWM signal, and send communication information to the driving unit 102;

[0070] The driving unit 102 is further used to generate M control signals according to the communication information, and control the M*N LED lights in the pixel array through the M control signals.

[0071] The M switch sub-units 1022 are further used to generate M control signals according to the M first pulse signals and the M second pulse signals, and control the M*N LED lamps in the pixel array through the M control signals.

[0072] Take the 4*16 matrix Mini-LED backlight circuit as an example. Figure 7 As shown, it is a schematic diagram of a 4*16 matrix Mini-LED backlight source circuit provided in an embodiment of the present application. In the figure, there are 4x16=64 Mini-LEDs in total, which are divided into 4 rows (L0~L3) and 16 columns (C0~C15).

[0073] like Figure 8 As shown, it is a 4*16 matrix Mini-LED backlight source driving circuit provided in an embodiment of the present application. The driving chip is used to drive the rows (L0~L3) of the Mini-LED backlight source circuit. The first signal output terminal of the driving chip outputs a first pulse signal to G0, G1, G2 and G3, and the second signal output terminal normally outputs a second pulse signal with a duty cycle of 50% to L0, L1, L2 and L3. Since G0~G4 are respectively connected to the gates (Gate) of 4 MOS tubes, taking the PMOS tube as an example, when the gate (Gate) voltage is set low, the MOS tube is turned on, and the power supply VCC forces the corresponding row Lx to be set high. The waveform diagram output by the driving chip 1021 is shown as follows: Fig. 9 shown.

[0074] like Fig.10The above is a PWM waveform diagram output by the MCU, where Base is the reference PWM waveform, which is only used for reference. The MCU sends out 4 PWM signals PWM0~PWM3 with a duty cycle of 50%, which are connected to the cathodes C0~C15 of the Mini-LED through the isolation chip. Here, PWM0 is the reference waveform, the initial phase of PWM1 is delayed by 1 / 8 cycle compared with PWM0, the initial phase of PWM2 is delayed by 1 / 4 cycle compared with PWM0, and the initial phase of PWM3 is delayed by 3 / 8 cycle compared with PWM0, that is, the initial phases of the four PWM signals are delayed by 1 / 8 cycle respectively.

[0075] like Fig.11 As shown in the figure, it is a schematic diagram of the Mini-LED working waveform. When the anode Lx of a Mini-LED is at a high potential and the cathode Cx is at a low potential, the Mini-LED lights up. Fig.11 It can be seen that at time T0, the driver chip sets G0 to low, VCC and L0 are turned on, L0 outputs a high level, and PWM0 is at a low level, so the four Mini-LEDs (L0, C0), (L0, C4), (L0, C8), and (L0, C12) light up first, and the other lights are not on. After a delay of 1 / 8 PWM cycle, the four Mini-LED lights (L0, C1), (L0, C5), (L0, C9), and (L0, C13) light up, and after a delay of 1 / 8 PWM cycle, the four Mini-LED lights (L0, C2), (L0, C6), (L0, C10), and (L0, C14) light up, and finally all lights light up after a delay of 1 / 8 PWM cycle.

[0076] At T1, the driver chip sets G0 high, VCC and L0 are not conducting, and L0 is still at a high level. As PWM0~PWM3 turn from low to high, the Mini-LED enters the shutdown process, and the shutdown is smooth in the same order as the startup.

[0077] At T2, all 16 Mini-LEDs of L0 are turned off, and the 16 Mini-LEDs of L1 are switched on and off in the same order as L0.

[0078] At time T4, after 4 PWM cycles, all Mini-LEDs from L0 to L3 have been switched on and off once, and the cycle starts again from T0.

[0079] Through the backlight source driving circuit of the present application, when the Mini-LED backlight is working, through the phase shift of PWM, only 4 Mini-LEDs are turned on or off at a certain moment, avoiding the impact of simultaneous switching of 16 Mini-LEDs of Lx on the power supply, extending the service life of the Mini-LED, and at the same time, since the total switching time of a single Mini-LED remains unchanged, the brightness requirement of the backlight is guaranteed.

[0080] In addition, compared with the traditional control scheme, this scheme uses only one driver chip, and the Mini-LED cathode adopts the solution of MCU output PWM and isolation chip, which reduces the number of driver chips and reduces production costs. The use of VSYN synchronization signal ensures that the initial phase of the driver chip 1021 and the MCU output PWM are the same.

[0081] It is worth noting that the above process is only described using a 4*16 matrix Mini-LED backlight circuit as an example, but it is also applicable to other matrix backlight circuits. The PWM0~PWM3 phase delay described above is in units of 1 / 8 PWM cycle, and can also be delayed by a preset cycle of 1 / 16, or by a preset cycle of 1 / 9, without any limitation. The preset delay cycle is 1 / 8 cycle, which can reduce the impact current while ensuring that the backlight brightness is not affected.

[0082] Based on the same concept, the embodiment of the present application also provides a backlight source driving method, the implementation of which can refer to the implementation of the above circuit, and the repeated parts will not be repeated. Fig.12 As shown, the backlight source driving method includes:

[0083] S1201, the control unit outputs a PWM signal, controls the pixel array through the PWM signal, and sends communication information to the driving unit; wherein the PWM signal is X, X is less than or equal to N, and the initial phases of the X PWM signals are delayed by a preset period in sequence;

[0084] S1202, the driving unit generates M control signals according to the communication information, and controls the pixel array through the M control signals; wherein M, N, and X are all positive integers.

[0085] Based on the same concept, an embodiment of the present application further provides a display screen, comprising a pixel array of M rows and N columns and a backlight source driving circuit as described above.

[0086] The embodiment of the present application provides a backlight driving circuit, a driving method and a display screen, the backlight driving circuit is applied to a pixel array of M rows and N columns, and includes a control unit and a driving unit; the control unit is connected to the first end of the pixel array and the driving unit respectively; the driving unit is also connected to the second end of the pixel array; the control unit is used to output a PWM signal, control the pixel array through the PWM signal, and send communication information to the driving unit; wherein the PWM signal is X, X is less than or equal to N, and the initial phases of the X PWM signals are sequentially delayed by a preset period; the driving unit is used to generate M control signals according to the communication information, and control the pixel array through the M control signals; wherein M, N, and X are all positive integers. Since the control unit can output X PWM signals with initial phases sequentially delayed by a preset period, and send the PWM signal to the first end of the pixel array to control the pixel array, it is possible to drive only the pixel units less than N in the pixel array at the same time, instead of driving N pixel units at the same time, thereby reducing the impact current generated by the backlight driving circuit when driving the pixel array.

[0087] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0088] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0089] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1A function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0091] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A backlight source driving circuit, applied to a pixel array of M rows and N columns, characterized in that: include: Control unit and drive unit; The control unit is connected to the first end of the pixel array and the driving unit respectively; the driving unit is also connected to the second end of the pixel array; The control unit is used to output a PWM signal, control the pixel array through the PWM signal, and send communication information to the driving unit; wherein the PWM signal is X, X is less than or equal to N, and the initial phases of the X PWM signals are delayed by a preset period in sequence; The driving unit is used to generate M control signals according to the communication information, and control the pixel array through the M control signals; wherein M, N, and X are all positive integers.

2. The circuit according to claim 1, characterized in that The driving unit includes a driving chip and M switch sub-units; The SPI interface end of the driving chip is connected to the SPI interface end of the control unit; the M first signal output ends of the driving chip are respectively connected to the control ends of the M switch subunits, the M second signal output ends of the driving chip are respectively connected to the first ends of the M switch subunits, and the M second signal output ends of the driving chip are also respectively connected to the second ends of the pixel array; the second ends of the M switch subunits are respectively connected to the power supply end; The driving chip is used to receive the communication information sent by the control unit, generate M first pulse signals and M second pulse signals according to the communication information, and send the M first pulse signals and the M second pulse signals to the M switch sub-units; The M switch sub-units are used to generate the M control signals according to the M first pulse signals and the M second pulse signals, and control the pixel array through the M control signals.

3. The circuit according to claim 2, characterized in that The control unit is further used to send a synchronization signal to the driving chip so that the PWM signal output by the control unit is synchronized with the output time of the M first pulse signals and the M second pulse signals generated by the driving chip.

4. The circuit according to claim 2, characterized in that The M switch sub-units include M switch tubes; The control ends of the M switch tubes serve as the control ends of the M switch sub-units, the first ends of the M switch tubes serve as the first ends of the M switch sub-units, and the second ends of the M switch tubes serve as the second ends of the M switch sub-units.

5. The circuit according to claim 4, characterized in that The M switch tubes are all MOS tubes; The gates of the M MOS tubes serve as the control ends of the M switch tubes, the drains of the M MOS tubes serve as the first ends of the M switch tubes, and the sources of the M MOS tubes serve as the second ends of the M switch tubes; or The gates of the M MOS tubes serve as control ends of the M switch tubes, the sources of the M MOS tubes serve as first ends of the M switch tubes, and the drains of the M MOS tubes serve as second ends of the M switch tubes.

6. The circuit according to claim 1, characterized in that Also includes isolation chips; The control unit is connected to the first end of the pixel array through the isolation chip; The isolation chip is used to perform signal isolation between the first end of the pixel array and the control unit.

7. The circuit according to claim 2, characterized in that Each pixel unit of the pixel array is an LED lamp; The cathodes of the M*N LED lamps serve as the first end of the pixel array, and the anodes of the M*N LED lamps serve as the second end of the pixel array; The control unit is further used to output a PWM signal, control the LED lights in the pixel array through the PWM signal, and send communication information to the driving unit; The driving unit is further used to generate M control signals according to the communication information, and control the M*N LED lights in the pixel array through the M control signals.

8. The circuit according to claim 7, characterized in that The M switch sub-units are further used to generate M control signals according to the M first pulse signals and the M second pulse signals, and control the M*N LED lamps in the pixel array through the M control signals.

9. A backlight driving method, characterized in that: include: The control unit outputs a PWM signal, controls the pixel array through the PWM signal, and sends communication information to the driving unit; wherein the number of the PWM signals is X, X is less than or equal to N, and the initial phases of the X PWM signals are sequentially delayed by a preset period; The driving unit generates M control signals according to the communication information, and controls the pixel array through the M control signals; wherein M, N, and X are all positive integers.

10. A display screen, characterized in that: The invention comprises a pixel array of M rows and N columns and a backlight source driving circuit as claimed in any one of claims 1 to 8.

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