Display device and backlight adjustment method

Abstract

The present invention discloses a display device and a backlight adjustment method. The display device includes: a plurality of lamp boards, a driving chip on each lamp board being electrically connected to a backlight partition; a power module for providing a backlight supply voltage to the backlight partition; and a controller for supplying power to each backlight partition according to the backlight supply voltage, and sending the converted brightness information to the driving chip. The driving chip is used to drive the LED lamps in the backlight partition according to the brightness information, and to send the voltage data of the backlight partition to the controller. The controller is also used to control the power module to adjust the backlight supply voltage according to all the voltage data until the voltage value of the LED lamp with the lowest voltage reaches a preset voltage value. The present application collects the voltage data of the backlight partition and adjusts the backlight supply voltage in real time according to the voltage data, so that the voltage of all LED lamps meets the requirements, while avoiding a large amount of energy waste, thereby improving the energy efficiency of the display device.

Description

Technical Field

[0001] The present invention relates to the field of LED technology, and in particular to a display device and a backlight adjustment method. Background Art

[0002] The backlight source of Mini-LED (Mini Light-emitting Diode) display device is composed of tens of thousands of LED lights. In order to facilitate production and design, the backlight source is generally evenly divided into several pieces. In order to facilitate wiring and reduce cost interference, the LED chip is directly placed on the light board, and the driver chip and LED chip are on the same side. Each light board can adopt the same design and share the same PCB.

[0003] Please refer to Figure 4 The Mini-LED display device mainly includes: power module, mainboard, controller, T-CON (screen drive circuit) and lamp board with integrated driver chip. The main function of the controller is to generate a drive signal to the driver chip on the corresponding lamp board according to the brightness information sent by the mainboard. The driver chip controls the current size of the corresponding partition LED according to the drive signal to achieve the corresponding brightness. Please refer to Figure 1 and Figure 2 Generally, the power module outputs a fixed voltage to the controller, and the controller then supplies the voltage to each light board. Therefore, all partitioned LEDs are common anodes, that is, they are all powered by one voltage.

[0004] When each backlight partition is powered by the same voltage, due to line loss, the controller needs to provide 3A or even higher current to each light board. Figure 3 , the voltage of the partitions near points A, B, C, and D, which are far from the power module, is inevitably lower than the voltage of the partition near point E, which is close to the power module. In order to ensure that the Mini-LED in each partition can be turned on normally, the output voltage of the power module used to supply power to the light board has to be increased, so that the LED lights at points A, B, C, and D, where the voltage at both ends of the lamp beads is low due to line loss, can be fully lit. At this time, the voltage is too high for the partition near point E close to the power module, and the excess voltage has to be wasted on the drive circuit and wiring, which will generate a lot of heat and cause low energy efficiency.

[0005] In addition to line loss, there are also differences in voltage between Mini-LED lamps. In order to ensure that all Mini-LED lamps are fully lit, for systems with fixed power supply voltage output, the voltage has to be increased to ensure that the high-voltage Mini-LED can be fully lit. For low-voltage Mini-LED, the output voltage is too high, and the excess voltage needs to be lost in the circuit. Therefore, for the Mini-LED fixed voltage power supply drive system, its energy efficiency ratio will be very poor, which leads to a waste of power supply power. In addition to affecting the reliability of Mini-LED backlight and drive, it also increases the power supply cost. At the same time, it also increases the difficulty of power supply design due to power supply reasons.

[0006] It can be seen that the current display devices have voltage differences between different lamp beads, and line losses will inevitably lead to voltage differences between different partitions, resulting in the traditional Mini-LED driving fixed voltage power supply system can only output a higher voltage to meet all situations. This voltage is too high for some Mini LED lamps, and the excess voltage can only be lost in the circuit, causing a large amount of energy loss. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a display device and a backlight adjustment method to solve the problem of low energy efficiency of existing display devices.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] A display device, comprising:

[0010] A plurality of light boards, each light board being provided with a driver chip, and the driver chip being electrically connected to at least one backlight partition corresponding to the light board;

[0011] A power supply module, used for providing a backlight power supply voltage to the backlight partition; and

[0012] A controller, the controller is electrically connected to the light board and the power module, and is used to supply power to each of the backlight partitions according to the backlight power supply voltage, receive brightness information sent by the main board, and send a driving signal to the driving chip according to the brightness information;

[0013] The driver chip is used to drive the LED lamp in the backlight partition according to the drive signal, and send voltage data of the backlight partition to the controller;

[0014] The controller is also used to control the power module to adjust the backlight supply voltage according to all the voltage data until the voltage value of the LED lamp with the minimum voltage reaches a preset voltage value.

[0015] Furthermore, the driver chip includes:

[0016] a driving unit, the driving unit being electrically connected to the controller, the PWM control unit and the current control unit respectively, and being configured to receive the driving signal and drive the PWM control unit and the current control unit according to the driving signal;

[0017] The PWM control unit is electrically connected to the control end of the switch unit and is used to send a first PWM signal to the control end of the switch unit to control the switch unit to be turned on and off;

[0018] The switch unit, wherein the input end of the switch unit is connected to the negative terminal of the backlight partition, and the output end of the switch unit is grounded;

[0019] The current control unit is electrically connected to the output ends of the driving unit and the switching unit respectively, and is used to detect and adjust the current flowing through the corresponding backlight partition, and enable the voltage detection unit through the driving unit when the switching unit is turned on and the current flowing through the switching unit is stable; and

[0020] The voltage detection unit is electrically connected to the input terminals of the driving unit and the switching unit respectively, and is used to collect the voltage value of the negative terminal of the backlight partition and send the voltage value to the driving unit;

[0021] The driving unit is further configured to send the voltage data to the controller according to the voltage value.

[0022] Furthermore, the display device also includes a feedback module, which is electrically connected to the controller and the power module respectively. The controller sends an adjustment signal to the feedback module according to the voltage signal. The feedback module is used to adjust the voltage of the feedback receiving end of the power module according to the voltage signal. The power module adjusts the backlight power supply voltage accordingly according to the voltage change of the feedback receiving end.

[0023] Further, the regulating signal is a second PWM signal, and the feedback module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor and a first diode;

[0024] One end of the first resistor is connected to the adjustment signal output end of the controller, and the other end of the first resistor is connected to the cathode of the first diode;

[0025] The anode of the first diode is connected to one end of the second resistor, and the other end of the second resistor is connected to the feedback receiving end of the power module;

[0026] One end of the first capacitor is connected to the cathode of the first diode, and the other end of the first capacitor is grounded;

[0027] One end of the third resistor is connected to the other end of the first resistor, and the other end of the third resistor is connected to the other end of the first capacitor;

[0028] One end of the fourth resistor is connected to the other end of the second resistor, and the other end of the fourth resistor is connected to the backlight power supply voltage;

[0029] One end of the fifth resistor is connected to the other end of the second resistor, and the other end of the fifth resistor is grounded.

[0030] Further, the adjustment signal is a DAC signal, and the feedback module includes: a second capacitor, a second diode, a sixth resistor, a seventh resistor and an eighth resistor;

[0031] The cathode of the second diode is connected to the regulating signal output terminal of the controller, the anode of the second diode is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the feedback receiving terminal of the power module;

[0032] One end of the second capacitor is connected to the cathode of the second diode, and the other end of the second capacitor is grounded;

[0033] One end of the seventh resistor is connected to the other end of the sixth resistor, and the other end of the seventh resistor is connected to the backlight power supply voltage;

[0034] One end of the eighth resistor is connected to the other end of the sixth resistor, and the other end of the eighth resistor is grounded.

[0035] A backlight adjustment method, applied to any of the above-mentioned display devices, comprises the steps of:

[0036] The power module provides the backlight power supply voltage to the controller;

[0037] The controller supplies power to each backlight partition according to the backlight power supply voltage, receives brightness information sent by the mainboard, and sends a driving signal to the driving chip according to the brightness information;

[0038] The driver chip drives the LED lamp in the backlight partition according to the drive signal, and sends voltage data of the backlight partition to the controller;

[0039] The controller controls the power module to adjust the backlight supply voltage according to all the voltage data until the voltage of the LED lamp with the lowest voltage reaches a preset voltage threshold.

[0040] Further, the step of the driver chip driving the LED lamp in the backlight partition according to the drive signal, and sending the voltage data of the backlight partition to the controller includes:

[0041] The driving unit receives the driving signal, and drives the PWM control unit and the current control unit according to the driving signal;

[0042] The PWM unit sends a first PWM signal to the switch unit to turn the switch unit on or off;

[0043] The current control unit detects and adjusts the current flowing through the corresponding backlight partition, and enables the driving unit to enable the voltage detection unit when the switch unit is turned on and the current flowing through the switch unit is stable;

[0044] The voltage detection unit collects the voltage value of the negative terminal of the backlight partition and sends the voltage value to the driving unit;

[0045] The driving unit sends voltage data to the controller according to the voltage value.

[0046] Furthermore, the lamp board is provided with a single or multiple drive links, each of the drive links includes multiple drive chips connected in series, and the drive chip sends the voltage data to the controller through the drive link.

[0047] Further, the controller controls the power module to adjust the backlight power supply voltage according to all the voltage data, comprising:

[0048] Obtaining a minimum voltage value among the voltage data sent by each drive link;

[0049] Compare the minimum voltage value with a first maximum voltage preset threshold and a minimum voltage preset threshold respectively;

[0050] The backlight power supply voltage is adjusted according to the comparison result until the minimum voltage value sent by each of the driving links is between the first maximum voltage preset threshold value and the minimum voltage preset threshold value.

[0051] Further, the controller controls the power module to adjust the backlight power supply voltage according to all the voltage data, comprising:

[0052] Obtaining a minimum voltage value among the voltage data sent by all the drive links, and obtaining the minimum voltage value with the smallest value;

[0053] Compare the minimum voltage value with the first maximum voltage preset threshold and the minimum voltage preset threshold respectively;

[0054] The backlight power supply voltage is adjusted according to the comparison result until the minimum voltage value with the smallest value is between the first maximum voltage preset threshold value and the minimum voltage preset threshold value.

[0055] The beneficial effect of the present invention is that while driving the LED lights in the backlight partition through the driving chip, the voltage data of the backlight partition is collected and sent to the controller. The controller controls the power module in real time to adjust the backlight supply voltage according to the voltage data, forming a closed-loop control, so that the voltage of all LED lights meets the requirements, while avoiding a large amount of energy waste, thereby reducing the power consumption of the Mini-LED backlight, thereby improving the energy efficiency of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 A schematic diagram of installing a light panel of a display device in the prior art;

[0057] Figure 2 It is a schematic diagram of the structure of a display device in the prior art;

[0058] Figure 3 is another structural schematic diagram of a display device in the prior art;

[0059] Figure 4 It is a principle block diagram of a display device in the prior art;

[0060] Figure 5 is a principle block diagram of a display device according to an embodiment of the present invention;

[0061] Figure 6 This is the corresponding relationship diagram between the forward current If and the forward voltage Vf of Mini-LED;

[0062] Figure 7 is a principle block diagram of a driver chip according to an embodiment of the present invention;

[0063] Figure 8 Another principle block diagram of a driver chip according to an embodiment of the present invention;

[0064] Fig. 9 is a schematic diagram of a feedback module according to an embodiment of the present invention;

[0065] Fig.10 is another principle diagram of a feedback module according to an embodiment of the present invention;

[0066] Fig.11 is another principle block diagram of a display device according to an embodiment of the present invention;

[0067] Fig.12 This is a first flow chart of a backlight adjustment method according to a second embodiment of the present invention;

[0068] Fig.13is a second flow chart of the backlight adjustment method according to the second embodiment of the present invention;

[0069] Fig.14 is a third flow chart of the backlight adjustment method according to the second embodiment of the present invention;

[0070] Fig.15 is a fourth flow chart of the backlight adjustment method according to the second embodiment of the present invention;

[0071] Fig.16 is a fifth flow chart of the backlight adjustment method according to the second embodiment of the present invention;

[0072] Fig.17 This is a schematic diagram of backlight power supply voltage adjustment during the SDR and HDR switching process of the third embodiment of the present invention.

[0073] Description of labels:

[0074] 100, light board; 110, backlight partition; 120, driver chip; 130, driver link; 121, driver unit; 122, PWM control unit; 123, switch unit; 124, current control unit; 125, voltage detection unit; 200, power module; 300, controller; 400, main board; 500, feedback module. DETAILED DESCRIPTION

[0075] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0076] Embodiment 1

[0077] Please refer to Figures 5 to 10 , Embodiment 1 of the present invention is:

[0078] A display device includes a housing, in which a light board 100, a main board 400, a controller 300 and a power module 200 are installed. Figure 5, the light board 100 is set to be several, the light board 100 is provided with a driving chip 120, the driving chip 120 is electrically connected to at least one backlight partition 110 corresponding to the light board 100; a power module 200, used to provide a backlight power supply voltage to the backlight partition 110; and a controller 300, the controller 300 is electrically connected to the light board 100 and the power module 200, used to supply power to each of the backlight partitions according to the backlight power supply voltage, and receive brightness information sent by the main board 400, and send a driving signal to the driving chip 120 according to the brightness information; the driving chip 120 is used to drive the LED lamp in the backlight partition 110 according to the driving signal, and send voltage data of the backlight partition 110 to the controller 300; the controller 300 is also used to control the power module 200 to adjust the backlight power supply voltage according to all the voltage data until the voltage value of the LED lamp with the smallest voltage reaches a preset voltage value. The mainboard 400 is electrically connected to the power module 200 and the controller 300, and provides control signals to the power module 200 and the controller 300. Each driver chip 120 can drive a single or multiple backlight partitions 110, and a LED light string or a single LED light is set in a single backlight partition 110.

[0079] The working principle of the display device in this embodiment is as follows: after the display device is powered on, the mainboard 400 sends control signals to the power module 200 and the controller 300 respectively, so that the power module 200 and the controller 300 start working. The power module 200 provides the backlight supply voltage to the controller 300. Since each backlight partition 110 has a common anode, the controller 300 outputs the same backlight supply voltage to each backlight partition 110 respectively to provide power for all LED lights. The mainboard 400 also sends brightness information to the controller 300. The controller 300 obtains a driving signal based on the brightness information and sends the driving signal to each driving chip 120. Each driving chip 120 on the light board 100 drives the LED lights in the corresponding backlight partition 110 according to the driving signal to light up the LED lights. In addition, each driving chip 120 also obtains the voltage data of the corresponding driven backlight partition 110 and sends it to the controller 300. The controller 300 controls the power module 200 to adjust the backlight supply voltage according to the voltage data sent by all the driver chips 120 until the voltage value of the LED lamp with the lowest voltage reaches a preset voltage value, wherein the preset voltage value can be set to a suitable voltage range according to the required backlight power range.

[0080] For easier understanding, please refer to Figure 6Different currents If on the Mini LED lamp correspond to different voltages Vf. The larger the current If, the larger the voltage Vf required. When the voltage provided by the power module 200 cannot reach the Vf required by the Mini-LED lamp, the Mini-LED current cannot reach the set value If. Therefore, it can be determined whether the voltage of the power module 200 is appropriate by judging whether the current If reaches the set value.

[0081] Since there are thousands or tens of thousands of LED lamps in the Mini-LED backlight system, if the current of each lamp is detected, the system design will be large and complicated. For example, the total current of a certain line on each lamp board 100 can be selected as the basis for judgment, or the current of the Mini-LED lamp of a certain backlight partition 110 can be selected as the basis for judgment. Although this method has a simple circuit, it does not take into account the current of all Mini-LED lamps, and there may be missed judgments or over-judgments. In practice, some Mini-LED lamps may have currents that do not reach the set value, or the output voltage of the power module 200 exceeds the required set value.

[0082] In this embodiment, the voltage data of the backlight partition 110 is obtained to obtain the current value of the LED lamp or LED lamp string in the backlight partition 110, thereby obtaining the voltage value of each LED lamp. It can be understood that since the voltage data of all backlight partitions 110 are obtained, the controller 300 can obtain the voltage conditions of all LED lamps according to all voltage data, and control the power module 200 to adjust the backlight supply voltage in real time to achieve the purpose of adjusting the voltage of the LED lamp.

[0083] Specifically, when the voltage of one or more LED lamps among the voltages of the LED lamps obtained from the voltage data is less than the preset voltage value, the controller 300 controls the power module 200 to increase the backlight supply voltage, and accordingly, the voltage of each LED lamp is increased until the voltage of all LED lamps reaches the preset voltage value. In addition, when the voltage of the LED lamp with the lowest voltage is higher than the preset voltage value, the controller 300 controls the power module 200 to reduce the backlight supply voltage, and accordingly, the voltage of each LED lamp is reduced until the voltage of the LED lamp with the lowest voltage reaches the preset voltage value, so that all LED lamps can reduce unnecessary power consumption while meeting the voltage requirements, which is beneficial to improving the energy efficiency of the display device. In addition, since the voltage data is obtained and adjusted in real time, the backlight supply voltage adjustment is efficient and responsive.

[0084] Please refer to Figure 7Specifically, the driving chip 120 includes: a driving unit 121, a PWM (Pulse width modulation) control unit 122, a current control unit 124, a switch unit 123 and a voltage detection unit 125. The driving unit 121 is electrically connected to the controller 300, the PWM control unit 122 and the current control unit 124 respectively, and is used to receive the driving signal and drive the PWM control unit 122 and the current control unit 124 according to the driving signal. The PWM control unit 122 is electrically connected to the control end of the switch unit 123, and is used to send a first PWM signal to the control end of the switch unit 123 to control the opening and closing of the switch unit 123. The input end of the switch unit 123 is connected to the negative terminal of the backlight partition 110, and the output end of the switch unit 123 is grounded. The current control unit 124 is electrically connected to the output ends of the driving unit 121 and the switch unit 123, respectively, and is used to detect and adjust the current flowing through the corresponding backlight partition 110, and when the switch unit 123 is turned on and the current flowing through the switch unit 123 is stable, the voltage detection unit 125 is enabled through the driving unit 121. The voltage detection unit 125 is electrically connected to the input ends of the driving unit 121 and the switch unit 123, respectively, and is used to collect the voltage value of the negative terminal of the backlight partition 110, and send the voltage value to the driving unit 121. The driving unit 121 is also used to send the voltage data to the controller 300 according to the voltage value.

[0085] The working principle of the driver chip 120 in this embodiment is as follows: after receiving the driving signal, the driver unit 121 drives the PWM control unit 122 and the current control unit 124. The PWM control unit 122 outputs a first PWM signal according to the instruction of the driver unit 121 to control the switch unit 123 to be turned on or off. When the switch unit 123 is turned on, the corresponding backlight partition 110 forms a power-on circuit; when it is turned off, the corresponding backlight partition 110 forms a circuit break, thereby performing PWM dimming on the display device. The current control unit 124 detects the current at the output end of the switch unit 123 and adjusts the current size, thereby adjusting the current size of the corresponding LED lamp.

[0086] Please continue to refer to Figure 7, when the first PWM signal is at a high level, after a delay, the switch unit 123 is fully turned on and the current flowing through the switch unit 123 is stable, and the current control unit 124 sets the enable signal of the voltage detection unit 125 to high through the driving unit 121, enabling the voltage detection unit 125 to detect the negative terminal voltage of the backlight partition 110. When the voltage detection is completed, when the first PWM signal is at a low level, the current control unit 124 sets the enable signal of the voltage detection unit 125 to low through the driving unit 121, so that the voltage detection unit 125 stops working. In this embodiment, the driving chip 120 also includes a ninth resistor R9, the switch unit 123 is an NMOS tube, the gate of the NMOS tube is connected to the PWM control unit 122; the source of the NMOS tube is respectively connected to the current control unit 124 and one end of the ninth resistor R9, and the other end of the ninth resistor R9 is grounded; the drain of the NMOS tube is respectively connected to the negative terminal of the backlight partition 110 and the voltage detection unit 125. In other embodiments, the switch unit 123 can also be an electronic component such as a triode.

[0087] It can be understood that this embodiment realizes PWM dimming, voltage detection, return voltage data and driving of the corresponding LED lamp of the corresponding backlight partition 110 by setting various units on the driver chip 120, thereby improving the integration of the driver chip 120, avoiding the setting of separate functional components on the lamp board 100, and facilitating the optimization of the circuit structure.

[0088] For easier understanding, please continue to refer to Figure 7 , taking one of the driver chips 120 and the corresponding backlight partition 110 as an example, when the Mini LED in the backlight partition 110 is just turned on, the negative terminal voltage of the backlight partition 110 detected by the voltage detection unit 125 is V_LED-, and the current flowing through the backlight partition 110 is I_LED, which is equal to the current Isen output by the source of the NMOS tube. Figure 7 It can be seen that V_LED-=V_NMOS_ds+V_Isen, V_Isen=Isen*R9. When the NMOS tube is turned on, the voltage is V_NMOS_ds. When the NMOS tube is fully turned on, V_NMOS_ds=Isen*Rds, where Rds is the on-state internal resistance of the NMOS tube. Therefore, V_LED-=Isen*Rds+Isen*R9=Isen*(Rds+R9), where Rds is determined by the NMOS tube, and Rds and R9 are both fixed values. Therefore, when the hardware is fixed, it is possible to detect whether the current of the LED lamp reaches the set value by detecting the negative terminal voltage V_LED- of each backlight partition 110.

[0089] Please refer to Figures 9 to 11Specifically, the display device also includes a feedback module 500, and the feedback module 500 is electrically connected to the controller 300 and the power module 200 respectively. The controller 300 sends an adjustment signal to the feedback module 500 according to the voltage signal. The feedback module 500 is used to adjust the voltage of the feedback receiving end of the power module 200 according to the adjustment. The power module 200 adjusts the backlight supply voltage accordingly according to the voltage change of the feedback receiving end.

[0090] Please refer to Fig. 9 , Optionally, in this embodiment, the adjustment signal is a second PWM signal, and the feedback module 500 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1 and a first diode D1; one end of the first resistor R1 is connected to the adjustment signal output end of the controller 300, and the other end of the first resistor R1 is connected to the cathode of the first diode D1; the anode of the first diode D1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to the feedback receiving end of the power module 200; one end of the first capacitor C1 is connected to the cathode of the first diode D1, and the other end of the first capacitor C1 is grounded; one end of the third resistor R3 is connected to the other end of the first resistor R1, and the other end of the third resistor R3 is connected to the other end of the first capacitor C1; one end of the fourth resistor R4 is connected to the other end of the second resistor R2, and the other end of the four resistors is connected to the backlight power supply voltage; one end of the fifth resistor R5 is connected to the other end of the second resistor R2, and the other end of the fifth resistor R5 is grounded.

[0091] It can be understood that the controller 300 adjusts the voltage of the feedback receiving end of the power module 200 by outputting the second PWM signal and adjusting the voltage of the feedback receiving end of the power module 200 through the feedback module 500 to adjust the backlight power supply voltage. In this embodiment, the second PWM signal passes through the first resistor R1, the second resistor R2 and the first capacitor C1 to form a stable DC voltage V1 at the negative terminal of the first diode D1. Fig. 9 , V_LED=R4*(V_Rf / R5+(V_Rf-V_D1-V1) / R2)+V_Rf, where V_LED is the backlight power supply voltage, V_Rf is the common point voltage of the second resistor R2, the fourth resistor R4 and the fifth resistor R5, V_D1 is the voltage across the first diode D1, and R4, R5, V_D1 and R2 are all fixed values. Therefore, the voltage at point V1 is changed by the second PWM signal, thereby changing V_Rf, and the power module 200 monitors V_Rf in real time through the feedback receiving end, and in order to maintain V_Rf unchanged, the size of the backlight power supply voltage V_LED is adjusted in real time.

[0092] Please refer to Fig.10 , Optionally, in another embodiment, the adjustment signal is a DAC (Digital to analog converter) signal, and the feedback module 500 includes: a second capacitor C2, a second diode D2, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8. The cathode of the second diode D2 is connected to the adjustment signal output terminal of the controller 300, the anode of the second diode D2 is connected to one end of the sixth resistor R6, and the other end of the sixth resistor R6 is connected to the feedback receiving terminal of the power module 200; one end of the second capacitor C2 is connected to the cathode of the second diode D2, and the other end of the second capacitor C2 is grounded; one end of the seventh resistor R7 is connected to the other end of the sixth resistor R6, and the other end of the seventh resistor R7 is connected to the backlight power supply voltage; one end of the eighth resistor R8 is connected to the other end of the sixth resistor R6, and the other end of the eighth resistor R8 is grounded.

[0093] It can be understood that the control panel adjusts the voltage of the feedback receiving end of the power module 200 by outputting a DAC signal through the feedback module 500. The DAC signal passes through the second capacitor C2 and forms a stable DC voltage V2 at the negative terminal of the second diode D2. Fig.10 , V_LED=R7*(V_Rf / R8+

[0094] (V_Rf-V_D2-V2) / R6)+V_Rf, where V_LED is the backlight power supply voltage, V_Rf is the common point voltage of the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8, V_D2 is the voltage across the second diode D2, and R6, R7, V_D2 and R8 are all fixed values. Therefore, the voltage at point V2 is changed through the DAC signal, thereby changing V_Rf, and the power module 200 monitors V_Rf in real time through the feedback receiving end, and in order to maintain V_Rf unchanged, the size of the backlight power supply voltage V_LED is adjusted in real time.

[0095] Optionally, the feedback module 500 may be disposed on the same circuit board as the controller 300 or the power module 200, or may be disposed on the display device as a separate module.

[0096] Embodiment 2

[0097] Please refer to Figure 7 , Figure 8 , Figures 11 to 16 , Embodiment 2 provides a backlight adjustment method, which is applied to the display device described in the above embodiment.

[0098] Please refer to Fig.12 , the backlight adjustment method comprises the steps of:

[0099] S1, the power module 200 provides a backlight power supply voltage to the controller 300;

[0100] S2, the controller 300 supplies power to each backlight partition 110 according to the backlight power supply voltage, receives brightness information sent by the mainboard 400, and sends a driving signal to the driving chip 120 according to the brightness information;

[0101] S3, the driver chip 120 drives the LED lights in the backlight partition 110 according to the drive signal, and sends the voltage data of the backlight partition 110 to the controller 300;

[0102] S4. The controller 300 controls the power module 200 to adjust the backlight supply voltage according to all the voltage data until the voltage of the LED lamp with the lowest voltage reaches a preset voltage threshold.

[0103] The principle of the backlight adjustment method is that the power module 200 in the display device provides a backlight supply voltage to the controller 300. Since each backlight partition 110 has a common anode, the controller 300 outputs the same backlight supply voltage to each backlight partition 110 to provide power for all LED lamps. The controller 300 receives the brightness information sent by the mainboard 400, and sends a driving signal to each driving chip 120 according to the brightness information. The driving chip 120 drives the LED lamp in the corresponding backlight partition 110 according to the driving signal to light up the LED lamp. In addition, the controller 300 obtains the voltage data of the corresponding backlight partition 110 through the driving chip 120, and then controls the power module 200 to adjust the backlight supply voltage according to all the voltage data until the voltage value of the LED lamp with the smallest voltage reaches the preset voltage value.

[0104] It can be understood that the backlight power supply voltage of the display device is adjusted in real time and in a closed loop, and the power module 200 outputs the most suitable backlight power supply voltage. While all LED lamps can meet the voltage requirements, the LED lamp with the lowest voltage reaches the preset voltage value, which greatly reduces the overall loss of the display device and improves the reliability of the display device.

[0105] Please refer to Figure 7 and Figure 8In this embodiment, the driver chip 120 includes: a driver unit 121, a PWM control unit 122, a current control unit 124, a switch unit 123 and a voltage detection unit 125. The driver unit 121 is electrically connected to the controller 300, the PWM control unit 122 and the current control unit 124 respectively; the PWM control unit 122 is electrically connected to the control end of the switch unit 123; the input end of the switch unit 123 is connected to the negative end of the backlight partition 110, and the output end of the switch unit 123 is grounded; the current control unit 124 is electrically connected to the output ends of the driver unit 121 and the switch unit 123 respectively; the voltage detection unit 125 is electrically connected to the input ends of the driver unit 121 and the switch unit 123 respectively.

[0106] Please refer to Fig.13 Specifically, step S3 includes:

[0107] S31, the driving unit 121 receives a driving signal, and drives the PWM control unit 122 and the current control unit 124 according to the driving signal;

[0108] S32, the PWM unit sends a first PWM signal to the switch unit 123 to turn the switch unit 123 on or off;

[0109] S33, the current control unit 124 detects and adjusts the current flowing through the corresponding backlight partition 110, and enables the driving unit 121 to enable the voltage detection unit 125 when the switch unit 123 is turned on and the current flowing through the switch unit 123 is stable;

[0110] S34, the voltage detection unit 125 collects the voltage value of the negative terminal of the backlight partition 110, and sends the voltage value to the driving unit 121;

[0111] S35 . The driving unit 121 sends voltage data to the controller 300 according to the voltage value.

[0112] Among them, when the first PWM signal is at a high level, after a delay, the switch unit 123 is fully turned on and the current flowing through the switch unit 123 is stable, and the current control unit 124 sets the enable signal of the voltage detection unit 125 to high through the driving unit 121, enabling the voltage detection unit 125 to detect the negative terminal voltage of the backlight partition 110. When the voltage detection is completed, when the first PWM signal is at a low level, the current control unit 124 sets the enable signal of the voltage detection unit 125 to low through the driving unit 121, thereby stopping the voltage detection unit 125 from working.

[0113] Since the current of each lamp is detected and compared, the control system processing time will be very long, resulting in serious backlight tailing. Therefore, it is necessary to simplify the processing time of voltage data so that the controller 300 has more time to process the reception and distribution of brightness information and achieve a one-to-one correspondence between the Mini-LED backlight and the display screen.

[0114] Therefore, in this embodiment, the lamp board 100 is provided with a single or multiple drive links 130 , each of the drive links 130 includes a plurality of drive chips 120 connected in series, and the drive chip 120 sends the voltage data to the controller 300 through the drive link 130 .

[0115] Please refer to Fig.14 Optionally, a first implementation of step S4 includes:

[0116] S411, obtaining a minimum voltage value in the voltage data sent by one of the driving links 130;

[0117] S412, comparing the minimum voltage value with a first maximum voltage preset threshold and a minimum voltage preset threshold respectively;

[0118] S413, adjusting the backlight power supply voltage according to the comparison result until the minimum voltage value sent by the driving link 130 of this path is between the first maximum voltage preset threshold value and the minimum voltage preset threshold value.

[0119] Specifically, when the minimum voltage value is less than the minimum voltage preset threshold, the backlight power supply voltage is increased until the minimum voltage value is greater than the minimum voltage preset threshold. When the minimum voltage value is greater than the first maximum voltage preset threshold, the backlight power supply voltage is reduced so that the minimum voltage value is reduced to between the first maximum voltage preset threshold and the minimum voltage preset threshold. When the minimum voltage value is between the first maximum voltage preset threshold and the minimum voltage preset threshold, the backlight power supply voltage is not adjusted.

[0120] It can be understood that the drive link 130 only provides the minimum voltage value of the negative end of the backlight partition 110 and compares it with the preset voltage threshold, which can effectively reduce the processing time of the controller 300 and improve the efficiency and response speed of the backlight power supply voltage regulation. This solution only applies the voltage data returned by one of the drive links 130 as a reference for the voltage regulation of the power module 200. Since multiple driver chips 120 are connected in series in one drive link 130, the overall situation can be roughly reflected. The advantage is that the time for reading data can be reduced exponentially, the processing time of the controller 300 can be further reduced, and the efficiency and response speed of the backlight power supply voltage regulation can be improved. However, due to line loss or Mini-LED lamp voltage difference, it is impossible to determine whether the voltage of the LED lamps in other paths has reached the preset voltage value.

[0121] Please refer to Fig.15 , a second implementation of step S4 includes:

[0122] S421, obtaining a minimum voltage value in the voltage data sent by each driving link 130;

[0123] S422, comparing the minimum voltage value with a first maximum voltage preset threshold and a minimum voltage preset threshold respectively;

[0124] S423 , adjusting the backlight power supply voltage according to the comparison result until the minimum voltage value sent by each of the driving links 130 is between the first maximum voltage preset threshold and the minimum voltage preset threshold.

[0125] Specifically, when the minimum voltage value is less than the minimum voltage preset threshold, the backlight power supply voltage is increased until the minimum voltage value is greater than the minimum voltage preset threshold. When the minimum voltage value is greater than the first maximum voltage preset threshold, the backlight power supply voltage is reduced so that the minimum voltage value is reduced to between the first maximum voltage preset threshold and the minimum voltage preset threshold. When the minimum voltage value is between the first maximum voltage preset threshold and the minimum voltage preset threshold, the backlight power supply voltage is not adjusted until the minimum voltage value sent by each of the drive links 130 is between the first maximum voltage preset threshold and the minimum voltage preset threshold.

[0126] Through this method, this embodiment can keep the minimum voltage value of each driving link 130 within the threshold range, so that the voltage of all LED lamps meets the voltage requirements while reducing unnecessary power consumption. It can also appropriately reduce the processing time of the controller 300 and improve the efficiency and response speed of backlight power supply voltage regulation.

[0127] Please refer to Fig.16 , a third implementation of step S4 includes:

[0128] S431, obtaining a minimum voltage value among the voltage data sent by all the drive links 130, and obtaining the minimum voltage value with the smallest value;

[0129] S432, comparing the minimum voltage value with the first maximum voltage preset threshold and the minimum voltage preset threshold respectively;

[0130] S433: Adjust the backlight power supply voltage according to the comparison result until the minimum voltage value with the smallest value is between the first maximum voltage preset threshold and the minimum voltage preset threshold.

[0131] Specifically, when the minimum voltage value with the smallest numerical value is less than the minimum voltage preset threshold, the backlight power supply voltage is increased until the minimum voltage value with the smallest numerical value is greater than the minimum voltage preset threshold. When the minimum voltage value with the smallest numerical value is greater than the first maximum voltage preset threshold, the backlight power supply voltage is reduced so that the minimum voltage value with the smallest numerical value is reduced to between the first maximum voltage preset threshold and the minimum voltage preset threshold. When the minimum voltage value with the smallest numerical value is between the first maximum voltage preset threshold and the minimum voltage preset threshold, the backlight power supply voltage is not adjusted.

[0132] In order to avoid excessive voltage output, the fourth implementation of step S4 includes: based on one of the above three implementations, the maximum voltage value of each drive link 130 is also obtained. The maximum voltage value is compared with the second maximum voltage preset threshold; wherein the second maximum voltage preset threshold is greater than the first maximum voltage preset threshold. When the maximum voltage value of one of the drive links 130 is greater than the second maximum voltage preset threshold, the backlight power supply voltage is reduced until the maximum voltage value is reduced to the second maximum voltage preset threshold, even if the minimum voltage value is not within the preset range at this time. In the actual process, the second maximum voltage preset threshold can be set larger than the first maximum preset threshold to avoid the minimum voltage value being extremely less than the minimum voltage preset threshold, thereby causing the corresponding LED lamp to have too low brightness.

[0133] Embodiment 3

[0134] Embodiment 3 provides a method for switching between SDR (Standard Dynamic Range) and HDR (High Dynamic Range Imaging) applied to a display device.

[0135] There are currently two SDR and HDR switching solutions on the market. In the first solution, the current amplitude of the LED lamp is fixed. In the SDR state, the maximum duty cycle of the PWM signal in the PWM dimming process is 50%; in the HDR state, the PWM signal can reach 100%, doubling the HDR brightness. In this solution, the current amplitude of the LED lamp in the SDR and HDR states is the same, so the required backlight supply voltage is the same, and the switching between the two does not require the backlight supply voltage to be adjusted.

[0136] In the second solution, the current amplitude of the LED lamp is not fixed. The current of the LED lamp in the HDR state is several times that in the SDR state. Therefore, the backlight power supply voltage required in the two states is different, and the backlight power supply voltage needs to be adjusted.

[0137] Please refer to Fig.17 , in the time from 0 to T1: starting from the enable signal given by the mainboard 400, the controller 300 completes its own initialization and constant current initialization. At this time, the backlight is not controlled by the mainboard 400, and the controller 300 gives a default voltage to the power module 200, so that the power module 200 outputs a default initial voltage V_sdr (set according to the actual backlight effect), and the initial voltage V_sdr is used as the default value of the backlight power supply voltage. The controller 300 controls the power module 200 to adjust the backlight power supply voltage according to the V_LED-voltage returned by the reading, until the backlight power supply voltage reaches the appropriate voltage, and records the FB of the corresponding power module 200 (FB is the feedback of the power module 200, and the size of the backlight power supply voltage can be adjusted by adjusting the voltage at this point), and assigns this value to the FB of the power module 200 initialized by V_sdr. The controller 300 controls the power module 200 to adjust the backlight power supply voltage in real time according to the returned V_LED-data.

[0138] During the time period T1 to T2: When the controller 300 receives the instruction to switch to the HDR state, in order to prevent the brightness from changing suddenly, the current of the LED lamp gradually increases through several cycles during the time period T1 to T2 for smoothing. When the current of the LED lamp does not reach the HDR preset current value, the controller 300 controls the power module 200 to increase the backlight supply voltage (if the voltage is not increased at this time, the LED lamp current cannot reach the preset current value due to insufficient voltage), and the backlight supply voltage gradually increases to the default initial voltage V_hdr (set according to the actual backlight effect).

[0139] At time T2: the backlight supply voltage gradually rises to the default initial voltage V_hdr. Although the set current reaches the maximum value, the currents of all LED lamps collected at this time may not all reach the HDR preset current value (the voltage is not enough to make the currents of all LED lamps reach the HDR preset current value), and the backlight supply voltage of the power module 200 needs to be further increased.

[0140] During the time period from T2 to T3: the current reaches the HDR preset current value, and the controller 300 adjusts the voltage of the power module 200 according to the returned V_LED- voltage, so that at time T3, the backlight power supply voltage reaches the appropriate voltage, and records the corresponding FB, assigns this value to the V_hdr to initialize the default FB of the power module 200, and adjusts the FB of the power module 200 to this value when entering the HDR state next time. The SDR state switches to the HDR state, and the controller 300 controls the power module 200 to adjust the backlight power supply voltage in real time according to the returned V_LED- data.

[0141] During the time period from T4 to T5: when the controller 300 receives the signal to switch to the SDR state, the current of the LED lamp decreases to the initial value (the current value of T5 to T6) in sequence, and the controller 300 controls the power module 200 to reduce the backlight supply voltage, gradually reducing it to the backlight supply voltage corresponding to the FB saved in the SDR state, completing the switch from the HDR state to the SDR state. At the same time, the backlight supply voltage is adjusted in real time according to the returned V_LED-.

[0142] In order to reduce the complexity of the control system and improve efficiency, the controller 300 determines whether the current of the Mini LED lamp in the corresponding area reaches the preset current value based on the maximum and minimum values ​​of the voltage data returned by each driving link 130. This embodiment adopts this method to improve the energy efficiency of the entire display device. At the same time, the control board obtains the current value of the LED lamp based on the returned voltage data, and compares the current value of the LED lamp with the HDR preset current value, thereby adjusting the backlight power supply voltage, realizing the state switching between SDR and HDR. Compared with the power module 200 outputting a fixed backlight power supply voltage, the energy efficiency will be greatly improved.

[0143] In summary, the present invention provides a display device and a backlight adjustment method. A driver chip drives the LED lights in the backlight partition while collecting the voltage data of the backlight partition and sending it to the controller. The controller controls the power supply to adjust the backlight supply voltage in real time according to the voltage data to form a closed-loop control, so that the voltage of all LED lights meets the requirements while avoiding a large amount of energy waste, thereby reducing the power consumption of the Mini-LED backlight and improving the energy efficiency of the display device.

[0144] In addition, the driver chip is equipped with multiple units to complete PWM dimming, negative voltage acquisition of backlight partitions, etc., which optimizes the circuit structure and reduces the space occupied on the light board. In the backlight adjustment method, the maximum and minimum voltage values ​​of the voltage data are obtained and compared with the preset thresholds of each voltage, which effectively reduces the processing time and resource occupation of the controller, and is conducive to improving the adjustment efficiency and response speed of the backlight power supply voltage.

[0145] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A display device, characterized in that: include: A plurality of light boards, each light board being provided with a driver chip, and the driver chip being electrically connected to at least one backlight partition corresponding to the light board; A power module, used for providing backlight power supply voltage to the backlight partition; as well as A controller, the controller is electrically connected to the light board and the power module, and is used to supply power to each of the backlight partitions according to the backlight power supply voltage, receive brightness information sent by the main board, and send a driving signal to the driving chip according to the brightness information; The driver chip is used to drive the LED lamps in the backlight partition according to the drive signal, and send the voltage data of the backlight partition to the controller; the current value of the LED lamp or LED lamp string in the backlight partition is obtained by acquiring the voltage data of the backlight partition, thereby obtaining the voltage value of each LED lamp; The controller obtains the voltage conditions of all LED lamps according to all voltage data, and controls the power supply module to adjust the backlight supply voltage in real time; The driver chip comprises: a driving unit, the driving unit being electrically connected to the controller, the PWM control unit and the current control unit respectively, and being configured to receive the driving signal and drive the PWM control unit and the current control unit according to the driving signal; The PWM control unit is electrically connected to the control end of the switch unit and is used to send a first PWM signal to the control end of the switch unit to control the switch unit to be turned on and off; The switch unit, wherein the input end of the switch unit is connected to the negative terminal of the backlight partition, and the output end of the switch unit is grounded; The current control unit is electrically connected to the output ends of the driving unit and the switching unit respectively, and is used to detect and adjust the current flowing through the corresponding backlight partition, and enable the voltage detection unit through the driving unit when the switching unit is turned on and the current flowing through the switching unit is stable; and, the voltage detection unit, the voltage detection unit being electrically connected to the input ends of the driving unit and the switching unit respectively, for collecting the voltage value of the negative terminal of the backlight partition and sending the voltage value to the driving unit; The driving unit is further used to send the voltage data to the controller according to the voltage value; The controller is also used to control the power module to adjust the backlight supply voltage according to all the voltage data until the voltage value of the LED lamp with the minimum voltage reaches a preset voltage value.

2. The display device according to claim 1, characterized in that It also includes a feedback module, which is electrically connected to the controller and the power module respectively. The controller sends an adjustment signal to the feedback module according to the voltage data. The feedback module is used to adjust the voltage of the feedback receiving end of the power module according to the voltage data. The power module adjusts the backlight power supply voltage accordingly according to the voltage change of the feedback receiving end.

3. The display device according to claim 2, characterized in that: The regulating signal is a second PWM signal, and the feedback module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor and a first diode; One end of the first resistor is connected to the adjustment signal output end of the controller, and the other end of the first resistor is connected to the cathode of the first diode; The anode of the first diode is connected to one end of the second resistor, and the other end of the second resistor is connected to the feedback receiving end of the power module; One end of the first capacitor is connected to the cathode of the first diode, and the other end of the first capacitor is grounded; One end of the third resistor is connected to the other end of the first resistor, and the other end of the third resistor is connected to the other end of the first capacitor; One end of the fourth resistor is connected to the other end of the second resistor, and the other end of the fourth resistor is connected to the backlight power supply voltage; One end of the fifth resistor is connected to the other end of the second resistor, and the other end of the fifth resistor is grounded.

4. The display device according to claim 2, characterized in that: The adjustment signal is a DAC signal, and the feedback module includes: a second capacitor, a second diode, a sixth resistor, a seventh resistor, and an eighth resistor; The cathode of the second diode is connected to the regulating signal output terminal of the controller, the anode of the second diode is connected to one end of the sixth resistor, and the other end of the sixth resistor is connected to the feedback receiving terminal of the power module; One end of the second capacitor is connected to the cathode of the second diode, and the other end of the second capacitor is grounded; One end of the seventh resistor is connected to the other end of the sixth resistor, and the other end of the seventh resistor is connected to the backlight power supply voltage; One end of the eighth resistor is connected to the other end of the sixth resistor, and the other end of the eighth resistor is grounded.

5. A backlight adjustment method, applied to the display device according to any one of claims 1 to 4, characterized in that: Includes steps: The power module provides the backlight power supply voltage to the controller; The controller supplies power to each backlight partition according to the backlight power supply voltage, receives brightness information sent by the mainboard, and sends a driving signal to the driving chip according to the brightness information; The driver chip drives the LED lamp in the backlight partition according to the drive signal, and sends voltage data of the backlight partition to the controller; The controller controls the power module to adjust the backlight supply voltage according to all the voltage data until the voltage of the LED lamp with the lowest voltage reaches a preset voltage threshold.

6. The backlight adjustment method according to claim 5, characterized in that: The step of the driver chip driving the LED lamp in the backlight partition according to the drive signal, and sending the voltage data of the backlight partition to the controller comprises: The driving unit receives the driving signal, and drives the PWM control unit and the current control unit according to the driving signal; The PWM unit sends a first PWM signal to the switch unit to turn the switch unit on or off; The current control unit detects and adjusts the current flowing through the corresponding backlight partition, and enables the driving unit to enable the voltage detection unit when the switch unit is turned on and the current flowing through the switch unit is stable; The voltage detection unit collects the voltage value of the negative terminal of the backlight partition and sends the voltage value to the driving unit; The driving unit sends voltage data to the controller according to the voltage value.

7. The backlight adjustment method according to claim 5, characterized in that: The lamp board is provided with a single or multiple driving links, each of which includes multiple driving chips connected in series, and the driving chip sends the voltage data to the controller through the driving link.

8. The backlight adjustment method according to claim 7, characterized in that: The step of the controller controlling the power module to adjust the backlight power supply voltage according to all the voltage data comprises: Obtaining a minimum voltage value among the voltage data sent by each drive link; Compare the minimum voltage value with a first maximum voltage preset threshold and a minimum voltage preset threshold respectively; The backlight power supply voltage is adjusted according to the comparison result until the minimum voltage value sent by each of the driving links is between the first maximum voltage preset threshold value and the minimum voltage preset threshold value.

9. The backlight adjustment method according to claim 7, characterized in that: The step of the controller controlling the power module to adjust the backlight power supply voltage according to all the voltage data comprises: Obtaining a minimum voltage value among the voltage data sent by all the drive links, and obtaining the minimum voltage value with the smallest value; Compare the minimum voltage value with the first maximum voltage preset threshold and the minimum voltage preset threshold respectively; The backlight power supply voltage is adjusted according to the comparison result until the minimum voltage value with the smallest value is between the first maximum voltage preset threshold value and the minimum voltage preset threshold value.

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