CN116978312A - Display device and display control method - Google Patents

Display device and display control method Download PDF

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Publication number
CN116978312A
CN116978312A CN202210421396.1A CN202210421396A CN116978312A CN 116978312 A CN116978312 A CN 116978312A CN 202210421396 A CN202210421396 A CN 202210421396A CN 116978312 A CN116978312 A CN 116978312A
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CN
China
Prior art keywords
voltage
module
switch
energy storage
backlight control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210421396.1A
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Chinese (zh)
Inventor
庞震华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hisense Visual Technology Co Ltd
Original Assignee
Hisense Visual Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hisense Visual Technology Co Ltd filed Critical Hisense Visual Technology Co Ltd
Priority to CN202210421396.1A priority Critical patent/CN116978312A/en
Priority to PCT/CN2022/114035 priority patent/WO2023109168A1/en
Priority to CN202280067560.1A priority patent/CN118076995A/en
Priority to PCT/CN2022/121412 priority patent/WO2023201988A1/en
Publication of CN116978312A publication Critical patent/CN116978312A/en
Pending legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
    • H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • H02M3/33523—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters with galvanic isolation between input and output of both the power stage and the feedback loop

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application provides a display device and a display control method, comprising the following steps: the backlight control module is used for controlling the light emitting diode to emit light; the power supply interface is used for receiving direct current input voltage provided by the external adapter; the first voltage conversion module is used for generating a first voltage according to the direct current input voltage; the energy storage element is used for storing the first voltage and outputting the first voltage alternately with the first voltage conversion module; the negative electrode of the backlight control module is connected with the first voltage, and the positive electrode is connected with the direct current input voltage; and the feedback module is used for sending a feedback signal to the first voltage conversion module so as to adjust the required voltage of the backlight control module. The application is suitable for a power supply mode of a power adapter, takes the first voltage as a negative reference voltage of the backlight control module, and forms stepped power supply with direct current input voltage connected with the positive electrode of the backlight control module, thereby reducing heat loss; continuous power supply is realized by using the energy storage element; the power supply voltage is timely adjusted through real-time feedback, so that the light-emitting diode works stably.

Description

Display device and display control method
Technical Field
The present application relates to the field of display technologies, and in particular, to a display device and a display control method.
Background
With the development of electronic technology, the integration level of electronic devices including display devices such as televisions is higher and higher, and thus, higher and higher requirements are being put on the power supply of the display devices. In the related art, a power supply architecture of a display device is directly connected with commercial power alternating current, a special power supply circuit is configured in a power panel of the display device to perform treatments such as transformation and direct current conversion on the alternating current, and the display device at least comprises the following modules: a rectifier bridge, a power factor correction (Power Factor Correction, abbreviated as PFC) module and a resonant conversion circuit (LLC) module. The resonant conversion circuit (LLC) module is utilized to generate a plurality of direct current voltages, so that the power supply requirement of loads in the display device is met.
Along with the rising of power adapters and the popularization of gallium nitride devices, the power supply of the display device gradually develops into an external form, namely, the external power adapter is utilized to finish the treatments of transforming the alternating current, converting the alternating current into the direct current and the like, and a fixed direct current voltage is output. The display device is connected with a single fixed direct current input voltage provided by the power adapter.
Therefore, the power architecture of the display device based on alternating current is not suitable for the external adapter power supply mode. How to use the direct current voltage output by the external adapter to meet the power supply requirement of the load in the display device is a problem to be solved.
Disclosure of Invention
The application provides a display device and a display control method, which are used for meeting the power supply requirement of a load in the display device by utilizing direct-current voltage output by an external adapter.
In a first aspect, the present application provides a display device comprising: the backlight control module is used for controlling the light emitting diode to emit light, and the light emitting diode is used for lighting the screen of the display device; the power supply interface is used for receiving direct current input voltage provided by the external adapter; the first voltage conversion module is used for generating a first voltage according to the direct current input voltage; the energy storage element is connected with the first voltage conversion module and is used for storing first voltage; the energy storage element and the first voltage conversion module alternately output a first voltage; the negative electrode of the backlight control module is connected with a first voltage which is used as a negative reference voltage of the backlight control module; the positive electrode of the backlight control module is connected with the direct current input voltage; the sum of the absolute value of the direct current input voltage and the absolute value of the first voltage is equal to the required voltage of the backlight control module; and the feedback module is used for sending a feedback signal generated by the backlight control module to the first voltage conversion module, and the feedback signal is used for indicating the first voltage conversion module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
In some embodiments, the first voltage conversion module comprises: a charge pump module; a charge pump module for generating a first voltage in a charged state; and in a discharge state, providing a first voltage to the negative electrode of the backlight control module; the first end of the energy storage element is connected with the positive output end of the charge pump module and grounded; the second end of the energy storage element is connected with the negative output end of the charge pump module; the energy storage element is used for storing a first voltage when the charge pump module discharges; and providing a first voltage to the negative electrode of the backlight control module when the charge pump module is charged; the feedback signal is used for indicating the charge pump module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
In some embodiments, the first voltage conversion module comprises: a flyback isolation transformer module; the flyback isolation transformer module is used for generating a first voltage by the secondary winding when the primary winding is conducted and transmitting the first voltage to the negative electrode of the backlight control module; the first end of the energy storage element is connected with the forward output end of the flyback isolation transformer module and grounded; the second end of the energy storage element is connected with the negative output end of the flyback isolation transformer module; the energy storage element is used for storing a first voltage when the primary winding is conducted; and when the primary winding is cut off, providing a first voltage to the negative electrode of the backlight control module; the feedback signal is used for indicating the flyback isolation voltage transformation module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
In some embodiments, the charge pump module includes: the first controller, the first energy storage capacitor, the first switch, the second switch, the third switch and the fourth switch; the first end of the first switch is connected with the direct-current input voltage, and the second end of the first switch is connected with the first end of the second switch; the second end of the second switch is used as a positive output end of the charge pump module, is connected with the first end of the energy storage element and is grounded; the first end of the first energy storage capacitor is connected with the second end of the first switch and the first end of the second switch, and the second end of the first energy storage capacitor is connected with the first end of the third switch and the first end of the fourth switch; the second end of the fourth switch is grounded; the second end of the third switch is used as a negative output end of the charge pump module, is connected with the second end of the energy storage element and outputs a first voltage; the first controller is connected with control ends of the first switch, the second switch, the third switch and the fourth switch and is used for adjusting the first voltage by controlling the switching frequencies of the first switch, the second switch, the third switch and the fourth switch according to the feedback signal; the first switch and the fourth switch are simultaneously disconnected or connected; the second switch is turned off or on simultaneously with the third switch.
In some embodiments, the flyback isolation transformer module comprises: a primary winding, a secondary winding, a first diode, a second controller and a fifth switch; the first end of the primary winding is connected with the direct-current input voltage, the second end of the primary winding is connected with the first end of the fifth switch, and the second end of the fifth switch is grounded; the secondary winding is coupled with the primary winding, and the first end of the secondary winding is connected with the positive electrode of the first diode; the negative electrode of the first diode is used as a positive output end of the flyback isolation voltage transformation module, is connected with the first end of the energy storage element and is grounded; the second end of the secondary winding is used as a negative output end of the flyback isolation transformer module, is connected with the second end of the energy storage element and outputs a first voltage; and the second controller is connected with the control end of the fifth switch and is used for adjusting the first voltage by controlling the switching frequency of the fifth switch according to the feedback signal.
In some embodiments, the feedback module includes a level shifting circuit; the level conversion circuit receives the first feedback signal output by the backlight control module, converts the first feedback signal into a second feedback signal, and outputs the second feedback signal to the first voltage conversion module; wherein the reference voltages of the first feedback signal and the second feedback signal are different.
In some embodiments, the display device further comprises: a second diode; the positive pole of the second diode is connected with the second end of the energy storage element, and the negative pole of the second diode is connected with the first end of the energy storage element.
In some embodiments, the display device further comprises: a main board; the main board is connected with the power supply interface, and the direct current input voltage is used for supplying power to the main board.
In some embodiments, the display device further comprises a second voltage conversion module; the second voltage conversion module is connected with the power supply interface and the main board and is used for outputting second voltage according to the direct current input voltage, wherein the second voltage is the required voltage of the main board.
In a second aspect, the present application provides a display control method applied to the display device as in the first aspect, the display control method comprising: receiving a feedback signal, wherein the feedback signal is generated by a backlight control module and is sent by the feedback module; based on the feedback signal, the first voltage is adjusted to adjust the required voltage of the backlight control module.
The application provides a display device and a display control method, comprising the following steps: the backlight control module is used for controlling the light emitting diode to emit light, and the light emitting diode is used for lighting the screen of the display device; the power supply interface is used for receiving direct current input voltage provided by the external adapter; the first voltage conversion module is used for generating a first voltage according to the direct current input voltage; the energy storage element is connected with the first voltage conversion module and is used for storing first voltage; the energy storage element and the first voltage conversion module alternately output a first voltage; the negative electrode of the backlight control module is connected with a first voltage which is used as a negative reference voltage of the backlight control module; the positive electrode of the backlight control module is connected with the direct current input voltage; the sum of the absolute value of the direct current input voltage and the absolute value of the first voltage is equal to the required voltage of the backlight control module; and the feedback module is used for sending a feedback signal generated by the backlight control module to the first voltage conversion module, and the feedback signal is used for indicating the first voltage conversion module to adjust the first voltage so as to adjust the required voltage of the backlight control module. The application is provided with a power supply interface connected with the external adapter, and receives direct-current input voltage so as to adapt to the power supply mode of the external adapter; the first voltage generated by the direct current input voltage is used as a negative reference voltage of the backlight control module, and the direct current input voltage connected with the positive electrode of the backlight control module forms stepped power supply, so that the heat loss is reduced; the energy storage element is utilized to realize continuous power supply for the backlight control module; the power supply voltage of the backlight control module is timely adjusted through real-time feedback, so that the light emitting diode works stably.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
FIG. 1 is a schematic diagram of a display device with a stand-alone power panel;
fig. 2 is a schematic diagram showing a connection relationship between a power panel and a load of the device;
FIG. 3 is a schematic diagram of a television power architecture;
FIG. 4 is a schematic diagram of a power supply circuit for supplying power to a motherboard and an LED string light;
FIG. 5 is a schematic diagram of another power supply circuit for supplying power to a motherboard and an LED string light;
FIG. 6 is a schematic diagram of a power supply circuit for supplying power to a motherboard and an LED string;
FIG. 7 is a schematic diagram of an external adapter power mode according to an embodiment of the present application;
fig. 8 is a schematic diagram of a power supply circuit of a display device according to an embodiment of the present application;
fig. 9 is a schematic diagram of a power supply circuit of another display device according to an embodiment of the present application;
fig. 10 is a schematic diagram of a power supply circuit of a charge pump module according to an embodiment of the present application;
fig. 11 is a schematic diagram of a power supply circuit of another display device according to an embodiment of the present application;
fig. 12 is a schematic diagram of a power supply circuit structure of a flyback isolation transformer module according to an embodiment of the present application;
Fig. 13 is a schematic structural diagram of a level shifter circuit according to an embodiment of the present application;
fig. 14 is a schematic structural diagram of a level shifter circuit based on a charge pump module power supply circuit according to an embodiment of the present application;
fig. 15 is a schematic structural diagram of a level conversion circuit based on a flyback isolation transformer module power supply circuit according to an embodiment of the present application;
fig. 16 is a schematic diagram of a circuit structure for supplying power to a motherboard according to an embodiment of the present application;
fig. 17 is a schematic diagram of another circuit structure for supplying power to a motherboard according to an embodiment of the present application.
Specific embodiments of the present application have been shown by way of the above drawings and will be described in more detail below. The drawings and the written description are not intended to limit the scope of the inventive concepts in any way, but rather to illustrate the inventive concepts to those skilled in the art by reference to the specific embodiments.
Detailed Description
Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples do not represent all implementations consistent with the application. Rather, they are merely examples of apparatus and methods consistent with aspects of the application.
The terms "first," "second," "third," "fourth" and the like in the description and in the claims and in the above drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the application described herein may be implemented, for example, in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The scene in which the present application is applied and the problems that exist will be described with reference to the drawings. As the demand for information is increasing, various types of display devices, such as computers, televisions, projectors, and the like, are being developed. The power supply circuit is one of the most important circuit structures in the display device, and can provide electric energy for the display device, so that the display device can normally operate. Some display devices are provided with independent power boards, and some display devices integrate the power boards and the main boards into one.
Taking a display device provided with an independent power panel as an example, the structure of the display device will be described, referring to fig. 1, fig. 1 is a schematic structural view of the display device provided with the independent power panel, and as shown in fig. 1, the display device includes a display panel 1, a backlight assembly 2, a main board 3, a power panel 4, a rear case 5, and a base 6. Wherein the display panel 1 is used for presenting pictures to a user; the backlight assembly 2 is located below the display panel 1, usually some optical assemblies, and is used for providing enough brightness and uniformly distributed light sources to enable the display panel 1 to display images normally, the backlight assembly 2 further comprises a back plate 20, the main plate 3 and the power panel 4 are arranged on the back plate 20, some convex hull structures are usually stamped and formed on the back plate 20, and the main plate 3 and the power panel 4 are fixed on the convex hulls through screws or hooks; the rear shell 5 is arranged on the panel 1 in a covering way so as to hide parts of the display device such as the backlight assembly 2, the main board 3, the power panel 4 and the like, thereby having an attractive effect; and a base 6 for supporting the display device.
In some embodiments, fig. 2 is a schematic diagram of connection between a power panel and a load of a display device, as shown in fig. 2, the power panel 4 includes an input terminal 41 and an output terminal 42 (a first output terminal 421, a second output terminal 422, and a third output terminal 423 are shown in the figure), where the input terminal 41 is connected to a mains supply, the output terminal 42 is connected to the load, for example, the first output terminal 421 is connected to an LED light string for lighting a display screen, the second output terminal 422 is connected to an audio device, and the third output terminal 423 is connected to a motherboard. The power panel 4 needs to convert ac mains to dc power required by a load, and the dc power generally has different specifications, for example, 18V for sound, 12V for a panel, and the like.
In some embodiments, taking a television as an example to describe a power architecture of a display device, fig. 3 is a schematic diagram of the power architecture of the television, and as shown in fig. 3, a power panel may specifically include: a rectifier bridge, a power factor correction (Power Factor Correction, PFC) module and a resonant converter (LLC) module, the LLC module including a synchronous rectifier circuit (not shown in fig. 3), the PFC module being connected to the LLC module, the LLC module being connected to a load.
The rectifier bridge is used for rectifying input commercial alternating current and inputting full-wave signals to the PFC module. An electromagnetic interference (Electromagnetic Interference, EMI) filter (not shown in fig. 3) may be connected to the ac power source before it is input to the PFC module, to high frequency filter the input ac power source.
The PFC module can comprise a PFC inductor, a switching power device and a PFC control chip, and mainly performs power factor correction on an input alternating current power supply to output stable direct current bus voltage (such as 380V) to the LLC module. The PFC module can effectively improve the power factor of the power supply and ensure the same phase of voltage and current. Alternatively, in some embodiments, the PFC module may not be provided in the power architecture shown in fig. 3.
The LLC module can adopt a double-MOS tube LLC resonant conversion circuit, and a synchronous rectification circuit is arranged in the LLC module generally and mainly comprises a transformer, a controller, two MOS tubes and a diode. In addition, the LLC module may also include pulse frequency adjustment (Pulse frequency modulation, PFM) circuits, capacitors, inductors, and other components. The LLC module can specifically step down or step up the direct current bus voltage input by the PFC module and output constant voltage to a load. Typically, the LLC module is capable of outputting a variety of different voltages to meet the demands of different loads. Alternatively, in other embodiments, an LLC module such as that shown in FIG. 3 may be replaced with a flyback voltage conversion module that steps down or up the voltage and outputs a constant voltage to the load.
More specifically, taking a display device as an example of a television, fig. 4 is a schematic diagram of a power supply circuit for supplying power to a motherboard and an LED string. After the commercial power alternating current (100V-240V, 50-60 Hz) acquired by the power supply circuit sequentially passes through the filtering rectification module (rectifier bridge), the PFC module and the LLC isolation voltage conversion module, the commercial power alternating current supplies power to a main board, a multi-path LED lamp string and other loads (not shown in fig. 4) of the display device. The first secondary winding in the LLC isolation voltage conversion module provides a first voltage (for example, 12V) to the main board, the second secondary winding provides a second voltage (for example, 18V) to the main board, and the third secondary winding simultaneously provides voltages to the multi-path LED lamp strings.
The multi-path LED lamp string is used for lighting a display screen of a television, LED components in the multi-path LED lamp string need to work within a certain voltage drop range to achieve rated current of the LED components, for example, the multi-path LED lamp string is a 16-path LED lamp string, and under the condition that each lamp string comprises 9 LED components, the required working voltage range of the multi-path LED lamp string is 51.3V-58.5V under the condition of 120mA, and the total current is 1.92A.
Because the voltage range required by the multi-path LED lamp string is related to the working environment of the multi-path LED lamp string, the hardware characteristics of the LED components, the service life and other factors, the adjustment needs to be performed in real time. Therefore, the secondary winding of the LLC isolated voltage conversion module for supplying power to the multi-path LED lamp string is additionally connected with a voltage adjustment module (for example, a buck circuit or a boost circuit, in fig. 4, the boost circuit is taken as an example), and the voltage adjustment module can adjust the voltage directly output by the third secondary winding according to the real-time current feedback result of the multi-path LED lamp string, so that the multi-path LED driving module controls the multi-path LED lamp string to work with rated current according to the received adjusted voltage, and damage to components caused by excessive current flowing through LED components in the multi-path LED lamp string is prevented.
However, in the power supply circuit shown in fig. 4, the voltage stress of the voltage adjustment module provided for the multi-path LED lamp string in the power supply circuit is large, for example, when the voltage range required by the multi-path LED lamp string is 51.3V-58.5V, the voltage adjustment module needs to adjust the voltage of more than 50V by boosting or reducing, which results in a higher withstand voltage value of elements such as a switch tube and a capacitor in the voltage adjustment module, and thus occupies a larger area of the PCB board where the power supply circuit is located, and finally increases the cost of the power supply circuit.
Fig. 5 is a schematic diagram of another power supply circuit for supplying power to a motherboard and an LED string, where, unlike the power supply circuit shown in fig. 4, the form of "step power supply" is adopted in fig. 5, and two different secondary windings in the LLC isolated voltage conversion module supply power to the LED string. Specifically, the power supply circuit includes three power supply branches, a first power supply branch includes a first secondary winding in the LLC isolated voltage conversion module configured to output a first voltage (e.g., 12V) to a motherboard, a second power supply branch includes a second secondary winding in the LLC isolated voltage conversion module configured to output a second voltage as a fixed voltage, a third power supply branch includes a third secondary winding in the LLC isolated voltage conversion module configured to output a third voltage (e.g., 16V or 18V), and then a voltage adjustment module (low voltage buck/boost) converts the third voltage to a fourth voltage, and then provides a sum of the third voltage and the fourth voltage to the LED string. In the power supply process of the LED lamp string, as two different voltages respectively output by the second secondary winding and the third secondary winding are flexibly arranged, the voltage regulation module only needs to regulate the voltage output by one secondary winding with smaller voltage, so that the requirement on the withstand voltage value of elements such as a switch tube and a capacitor in the voltage regulation module is reduced, the area of a PCB where a power supply circuit is located is further reduced, and the cost of the power supply circuit is finally reduced.
Fig. 6 shows a schematic diagram of a power supply circuit for supplying power to a motherboard and an LED string, in which ac mains power (100V-240V, 50-60 Hz) obtained by the power supply circuit is respectively input to two PFC modules after passing through a filtering rectifier module (rectifier bridge), and each PFC module is connected to an LLC isolated voltage conversion module. One LLC isolation voltage conversion module supplies power to the main board, provides 12V voltage, 18V voltage or 9.1V voltage in standby to the main board, and can provide different voltages to the main board by adjusting the switching frequency or duty ratio of transistors in the LLC isolation voltage conversion module. Another LLC isolated voltage conversion module provides a voltage of 10-15V, a constant current of 18A, to a multi-path or single-path LED load, and adjusts the output voltage of the LLC module based on a feedback circuit.
With the development of electronic technology, the integration level of electronic devices including display devices such as televisions is higher and higher, and thus, higher and higher requirements are being put on the power supply of the display devices. In fig. 4, 5 and 6, the power supply structure of the display device is directly connected with the ac power of the utility power, and a special power supply circuit is configured in the power panel of the display device to perform the treatments of transforming the ac power, converting the ac power into the dc power, and the like, and the power supply structure at least comprises the following modules: a rectifier bridge, a power factor correction (Power Factor Correction, abbreviated as PFC) module and a resonant conversion circuit (LLC) isolated voltage conversion module. The resonant conversion circuit (LLC) is utilized to isolate the voltage conversion module to generate a plurality of direct current voltages, so that the power supply requirement of loads in the display device is met. The power supply structure comprises at least one filtering rectification module, at least one PFC module and at least one LLC isolation voltage conversion module, and the LLC isolation voltage conversion module comprises at least one secondary winding, so that the circuit structure of the power supply is complex, and accordingly, the complex circuit is unfavorable for improving the integration level.
Along with the rising of power adapters and the popularization of gallium nitride devices, the power supply of the display device gradually develops into an external form, namely, the external power adapter is utilized to finish the treatments of transforming the alternating current, converting the alternating current into the direct current and the like, and a fixed direct current voltage is output. Fig. 7 is a schematic diagram of an external adapter power supply mode according to an embodiment of the present application, which shows a structure diagram of supplying power to a display device, for example, a television, in the external adapter power supply mode. It can be seen that the display device (television shown in fig. 7) is connected to a single fixed dc input voltage provided by the power adapter via a cable.
In the above-mentioned power supply architecture of the display device shown in fig. 4, 5 and 6, the use of the secondary windings of the LLC isolated voltage conversion module to output multiple voltages for powering the load of the display device is not suitable for the external adapter power supply mode shown in fig. 7. How to utilize a single fixed dc input voltage provided by an external adapter to power a load of a display device is a problem to be solved.
Based on the above problems, the display device and the display control method provided by the application are provided with a power supply interface connected with an external adapter, and are used for receiving direct current input voltage so as to adapt to the power supply mode of the external adapter; generating a superposition voltage by using the direct-current input voltage, and superposing the superposition voltage and the direct-current input voltage to realize step power supply, thereby being beneficial to reducing heat loss; the energy storage element is utilized to realize continuous power supply for the backlight control module; the power supply voltage of the backlight control module is timely adjusted through real-time feedback, so that the light emitting diode works stably.
The following describes the technical scheme of the present application and how the technical scheme of the present application solves the above technical problems in detail with specific embodiments. The following embodiments may be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.
Fig. 8 is a schematic diagram of a power supply circuit of a display device according to an embodiment of the present application, including: the device comprises a backlight control module, a power supply interface, a first voltage conversion module, an energy storage element and a feedback module.
The backlight control module is used for controlling the light emitting diode to emit light, and the light emitting diode is used for lighting the screen of the display device; the power supply interface is used for receiving direct current input voltage provided by the external adapter; the first voltage conversion module is used for generating a first voltage according to the direct current input voltage; the energy storage element is connected with the first voltage conversion module and is used for storing first voltage; the energy storage element and the first voltage conversion module alternately output a first voltage.
The negative electrode of the backlight control module is connected with a first voltage which is used as a negative reference voltage of the backlight control module; the positive pole of the backlight control module is connected with the direct current input voltage. And the feedback module is used for sending a feedback signal generated by the backlight control module to the first voltage conversion module, and the feedback signal is used for indicating the first voltage conversion module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
The voltage at two sides of the backlight control module is the sum of the absolute value of the direct current input voltage and the first voltage. The dc input voltage corresponds to a "fixed voltage", and the first voltage corresponds to a "variable voltage". The circuit structure for supplying power to the backlight control module by adopting the fixed voltage and the variable voltage is step power supply, so that the requirements of withstand voltage values and the like of electrical elements in the first voltage conversion module can be reduced, and the purposes of reducing cost and improving efficiency are achieved; and simultaneously, the heat loss on the electrical element can be reduced.
As shown in FIG. 8, the external adapter receives AC mains power (100V-240V, 50-60 Hz), and the internal circuit of the external adapter can at least comprise a filtering rectification module, a PFC module and an LLC isolation voltage conversion module as shown in FIG. 7. The external adapter outputs a fixed DC voltage. The display device is provided with a power supply interface connected with the external adapter and is used for receiving direct-current input voltage so as to adapt to the power supply mode of the external adapter shown in fig. 7. Compared with fig. 4 to 6, the filter rectifying module, the PFC module and the LLC isolated voltage conversion module are not required to be arranged on the power panel of the display device, which is beneficial to simplifying the circuit.
In some embodiments, the energy storage element shown in fig. 8 may be a single energy storage capacitor or other energy storage circuit. The energy storage element is matched with the first voltage conversion module together, and outputs first voltage alternately to continuously provide negative reference voltage for the backlight control module so that the light emitting diode emits light stably.
In some embodiments, the first voltage conversion module shown in fig. 8 may be in the form of a charge pump. Fig. 9 is a schematic diagram of a power supply circuit of another display device according to an embodiment of the present application. As shown in fig. 9, the first voltage conversion module includes: a charge pump module. A charge pump module for generating a first voltage in a charged state; and in a discharge state, providing a first voltage to the negative electrode of the backlight control module; the first end of the energy storage element is connected with the positive output end of the charge pump module and grounded; the second end of the energy storage element is connected with the negative output end of the charge pump module; the energy storage element is used for storing a first voltage when the charge pump module discharges; and providing a first voltage to the negative electrode of the backlight control module when the charge pump module is charged; the feedback signal is used for indicating the charge pump module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
The first voltage conversion module in the form of a charge pump in this embodiment is a non-inductive DC-DC power converter, i.e. there is no inductive element in the voltage conversion in the form of a charge pump, so that the voltage conversion principle does not involve high-speed conversion of magnetic fields, i.e. high-speed conversion of electric-magnetic and magnetic-electric, and the electromagnetic interference problem is almost negligible. The voltage conversion principle in the form of a charge pump is to utilize high-speed charge and discharge of the internal capacitive element, and thus has the advantage of low electromagnetic interference. Besides low electromagnetic interference, the power supply has the advantages of larger regulating range of output voltage, high efficiency, small volume, low quiescent current, low minimum working voltage, low noise and the like. In addition, the integration of the capacitor is easier and cheaper than the integration of the inductor, so that the first voltage conversion module in the form of a charge pump is also easier to realize a high integration and is also less costly for the whole application circuit.
In some embodiments, the energy storage element shown in fig. 9 may be a single energy storage capacitor or other energy storage circuit. The energy storage element is matched with the charge pump module together, and outputs a first voltage alternately to continuously supply power to the backlight control module, so that the light-emitting diode emits light stably.
The principle of power supply by matching the first voltage conversion module and the energy storage element is described below with reference to specific circuit structure schematic diagrams of the charge pump module and the energy storage element.
In some embodiments, fig. 10 is a schematic diagram of a power supply circuit structure of a charge pump module according to an embodiment of the present application, where the energy storage element Cn is exemplified by a single energy storage capacitor. The charge pump module includes: the first controller, the first energy storage capacitor C1, the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4.
The first end of the first switch S1 is connected with the direct-current input voltage Vin, and the second end of the first switch S1 is connected with the first end of the second switch S2; the second end of the second switch S2 is used as a positive output end of the charge pump module, is connected with the first end of the energy storage element Cn and is grounded; the first end of the first energy storage capacitor C1 is connected with the second end of the first switch S1 and the first end of the second switch S2, and the second end of the first energy storage capacitor C1 is connected with the first end of the third switch S3 and the first end of the fourth switch S4; the second end of the fourth switch S4 is grounded; the second end of the third switch S3 is used as a negative output end of the charge pump module, and is connected with the second end of the energy storage element Cn to output the first voltage-Vo.
The first controller is connected with the control ends of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 and is used for adjusting the first voltage-Vo by controlling the switching frequencies of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 according to feedback signals; the first switch S1 and the second switch S2 have different switch states, and the first switch S1 and the fourth switch S4 are turned off or turned on at the same time; the second switch S2 is turned off or on simultaneously with the third switch S3.
Based on the power supply circuit shown in fig. 10, the principle that the charge pump module and the energy storage element cooperate to provide a negative reference voltage for the negative electrode of the backlight control module is as follows:
step (1): the first controller controls the first switch S1 and the fourth switch S4 to be simultaneously closed, and the second switch S2 and the third switch S3 to be simultaneously opened. At this time, the dc input voltage Vin charges the first energy storage capacitor C1 through the closed first switch S1, and controls the charging time of the first energy storage capacitor C1 by controlling the opening time of the second switch S2 and the third switch S3 and the closing time of the first switch S1 and the fourth switch S4, so as to control the energy storage voltage of the first energy storage capacitor C1. Let the storage voltage of the first storage capacitor C1 after charging be Vo, at this time, since the second end of the first storage capacitor C1 is grounded, the first end voltage of the first storage capacitor C1 is Vo.
Step (2): the first controller controls the first switch S1 and the fourth switch S4 to be opened simultaneously, and the second switch S2 and the third switch S3 to be closed simultaneously. At this time, the first end of the first energy storage capacitor C1 is grounded, so the second end voltage of the first energy storage capacitor C1 is-Vo (i.e., the first voltage), which is used to provide the negative reference voltage to the negative electrode of the backlight control module. Meanwhile, the first energy storage capacitor C1 charges the energy storage element Cn, so that the energy storage voltage of the charged energy storage element Cn is Vo. Since the first terminal of the energy storage element Cn is also grounded, the second terminal of the energy storage element Cn is-Vo (i.e., the first voltage).
Step (3): the first controller controls the first switch S1 and the fourth switch S4 to be simultaneously closed, and the second switch S2 and the third switch S3 to be simultaneously opened. And (3) repeating the charging process of the first energy storage capacitor C1 in the step (1). At this time, the first end of the energy storage element Cn is grounded, and the second end of the energy storage element Cn provides a negative reference voltage, i.e., the first voltage-Vo, to the negative electrode of the backlight control module.
The power supply circuit shown in fig. 10 generates the first voltage-Vo based on the dc input voltage Vin, and connects the first voltage-Vo to the negative electrode of the backlight control module to serve as the negative reference voltage of the backlight control module; the direct current input voltage Vin input by the positive electrode of the backlight control module is combined, so that the voltage at two ends of the backlight control module is the sum of the absolute value Vo of the direct current input voltage Vin and the first voltage, namely the required voltage Vled of the backlight control module is equal to vin+vo.
With the power supply circuit shown in fig. 10, only the magnitude of the first voltage Vo needs to be controlled to control the variation of the required voltage Vled of the backlight control module. The first controller controls the quantity of the electric charges transmitted by controlling the switching frequency or the duty ratio of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 based on the feedback signal, thereby achieving the purpose of controlling the required voltage Vled of the backlight control module.
The direct current input voltage Vin is relatively stable and is equivalent to a fixed voltage; the first voltage Vo corresponds to "fluctuating voltage". Since the dc input voltage Vin is relatively stable, the output voltage variation range of the first voltage Vo depends on the variation range required by the required voltage Vled of the backlight control module. The circuit structure for supplying power to the backlight control module by adopting the fixed voltage and the variable voltage is step power supply, so that the requirements of withstand voltage values and the like of electrical elements in the first voltage conversion module can be reduced, and the purposes of reducing cost and improving efficiency are achieved; and simultaneously, the heat loss on the electrical element can be reduced.
In some embodiments, the first voltage conversion module shown in fig. 8 may be in flyback isolated form. Fig. 11 is a schematic diagram of a power supply circuit of a display device according to another embodiment of the present application. As shown in fig. 11, the first voltage conversion module includes: and the flyback isolation transformer module.
The flyback isolation transformer module is used for generating a first voltage by the secondary winding when the primary winding is conducted and transmitting the first voltage to the negative electrode of the backlight control module; the first end of the energy storage element is connected with the forward output end of the flyback isolation transformer module and grounded; the second end of the energy storage element is connected with the negative output end of the flyback isolation transformer module; the energy storage element is used for storing a first voltage when the primary winding is conducted; and when the primary winding is cut off, providing a first voltage to the negative electrode of the backlight control module; the feedback signal is used for indicating the flyback isolation voltage transformation module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
Specifically, the flyback isolation type voltage conversion module adopted in the embodiment is electrically isolated through the primary winding and the secondary winding. The flyback specifically means that when the switching tube is switched on, the secondary winding transformer acts as an inductor, electric energy is converted into magnetic energy, and at the moment, an output loop has no current; in contrast, when the switching tube is turned off, the secondary winding transformer releases energy, magnetic energy is converted into electric energy, and current exists in the output loop. In the flyback voltage conversion module, the secondary winding transformer simultaneously serves as an energy storage inductor, and has the characteristics of fewer components, simple circuit, low cost, small volume and the like, and meanwhile, the use safety is improved through electrical isolation.
In some embodiments, the energy storage element shown in fig. 11 may be a single energy storage capacitor or other energy storage circuit. The energy storage element is matched with the flyback isolation voltage transformation module together, and alternately outputs a first voltage to continuously provide a negative reference voltage for the backlight control module so that the light-emitting diode emits light stably.
The principle of power supply by matching the first voltage conversion module and the energy storage element is described below by combining a specific circuit structure schematic diagram of the flyback isolation voltage conversion module and the energy storage element.
In some embodiments, fig. 12 is a schematic diagram of a power supply circuit structure of a flyback isolation transformer module according to an embodiment of the present application. The flyback isolation transformer module comprises: primary winding, secondary winding, first diode D1, second controller and fifth switch S5.
The first end of the primary winding is connected with the direct-current input voltage Vin, the second end of the primary winding is connected with the first end of the fifth switch S5, and the second end of the fifth switch S5 is grounded; the secondary winding is coupled with the primary winding, and the first end of the secondary winding is connected with the anode of the first diode D1; the negative electrode of the first diode D1 is used as a positive output end of the flyback isolation voltage transformation module, is connected with the first end of the energy storage element Cn and is grounded; the second end of the secondary winding is used as a negative output end of the flyback isolation voltage transformation module, is connected with the second end of the energy storage element Cn, and outputs a first voltage-Vo.
The second controller is connected with the control end of the fifth switch S5 and is used for adjusting the first voltage-Vo by controlling the switching frequency of the fifth switch S5 according to the feedback signal.
Based on the power supply circuit shown in fig. 12, the principle that the flyback isolation transformer module and the energy storage element cooperate with each other to provide negative reference voltage for the negative electrode of the backlight control module is as follows:
step (1): the second controller controls the fifth switch S5 to be turned on, the current of the primary winding linearly increases, and the inductance energy storage increases; the first diode D1 is non-conductive. The stored voltage of the primary winding can be controlled by controlling the switching frequency of the fifth switch S5.
Step (2): the second controller controls the fifth switch S5 to be turned off, the primary winding current is cut off, and the first diode D1 is turned on. The first end of the secondary winding is grounded through a first diode D1, and the second end of the secondary winding can output a first voltage-Vo by setting the turn ratio of the primary winding to the secondary winding, so as to provide a negative reference voltage for the negative electrode of the backlight control module. Meanwhile, the secondary winding charges the energy storage element Cn, so that the energy storage voltage of the energy storage element Cn after charging is Vo. Since the first terminal of the energy storage element Cn is also grounded, the second terminal of the energy storage element Cn is-Vo (i.e., the first voltage).
Step (3): the second controller controls the fifth switch S5 to be turned on, and the energy storage process of the primary winding in the step (1) is repeated. At this time, the first end of the energy storage element Cn is grounded, and the second end of the energy storage element Cn provides a negative reference voltage, i.e., the first voltage-Vo, to the negative electrode of the backlight control module.
The power supply circuit shown in fig. 12 generates the first voltage-Vo based on the dc input voltage Vin, and connects the first voltage-Vo to the negative electrode of the backlight control module to serve as the negative reference voltage of the backlight control module; the direct current input voltage Vin input by the positive electrode of the backlight control module is combined, so that the voltage at two ends of the backlight control module is the sum of the absolute value Vo of the direct current input voltage Vin and the first voltage, namely the required voltage Vled of the backlight control module is equal to vin+vo.
With the power supply circuit shown in fig. 12, only the magnitude of the first voltage Vo needs to be controlled to control the variation of the required voltage Vled of the backlight control module. The second controller controls the quantity of the electric charges transmitted by controlling the switching frequency or the duty ratio of the fifth switch S5 based on the feedback signal, thereby achieving the purpose of controlling the required voltage Vled of the backlight control module.
The direct current input voltage Vin is relatively stable and is equivalent to a fixed voltage; the first voltage Vo corresponds to "fluctuating voltage". Since the dc input voltage Vin is relatively stable, the output voltage variation range of the first voltage Vo depends on the variation range required by the required voltage Vled of the backlight control module. The circuit structure for supplying power to the backlight control module by adopting the fixed voltage and the variable voltage is step power supply, so that the requirements of withstand voltage values and the like of electrical elements in the first voltage conversion module can be reduced, and the purposes of reducing cost and improving efficiency are achieved; and simultaneously, the heat loss on the electrical element can be reduced.
Fig. 13 is a schematic structural diagram of a level shifter circuit according to an embodiment of the present application. In some embodiments, the feedback module includes a level shifting circuit. The level conversion circuit receives the first feedback signal output by the backlight control module, converts the first feedback signal into a second feedback signal, and outputs the second feedback signal to the first voltage conversion module; wherein the reference voltages of the first feedback signal and the second feedback signal are different.
Since the reference voltage of the backlight control module is-Vo and the reference voltage of the first voltage conversion module is 0, the first feedback signal generated by the backlight control module cannot be directly transmitted to the first voltage conversion module, and therefore the first feedback signal with the reference low level-Vo is converted into the second feedback signal with the reference voltage of 0 by using the level conversion circuit. Wherein the level shift circuit can refer to the related art.
In some embodiments, the display device further includes a first filtering module; the first filtering module is connected with the power supply interface and the first voltage conversion module and is used for filtering direct-current input voltage. The first filtering module can be a filtering circuit formed by one or more grounded capacitances or a filtering circuit formed by a capacitor and an inductor. As shown in fig. 13, the first filter module takes the first filter capacitor C3 as an example, and the first filter capacitor C3 is connected in parallel between the dc input voltage of the power supply interface and the ground. The power supply is used for filtering clutter and alternating current components of a power supply, smoothing the pulsating direct current voltage and storing electric energy. The capacitance capacity of the filter capacitor is related to the purity of the load current and the power supply, and a filter capacitor with larger capacity is usually selected.
In some embodiments, the first filter capacitor C3 may be an electrolytic capacitor as shown in fig. 13. The electrolytic capacitor is one kind of capacitor, the metal foil is the positive electrode (aluminum or tantalum), the oxide film (aluminum oxide or tantalum pentoxide) closely attached to the metal with the positive electrode is the dielectric, and the cathode is composed of conductive material, electrolyte (electrolyte can be liquid or solid) and other materials, because the electrolyte is the main part of the cathode. The capacitance per unit volume is very large, and the preparation process is common industrial equipment because the preparation material is common industrial material, so that the preparation process can be used for mass production, and the cost is relatively low. It should be noted that the positive and negative of the electrolytic capacitor cannot be connected by mistake.
In some embodiments, the first filter capacitor C3 may also be other types of capacitors, such as ceramic band content, film capacitors, mica capacitors, and the like. In an actual circuit, the selection can be made according to the capacitance requirement.
In some embodiments, the display device further comprises a second filtering module; the second filtering module is arranged between the anode and the cathode of the backlight control module. The second filter module can be a filter circuit formed by one or more grounded capacitances or a filter circuit formed by a capacitor and an inductor. As shown in fig. 13, the second filter module is exemplified by a second filter capacitor C4, and is used for stabilizing the voltage across the backlight control module.
In some embodiments of the display device, a third filtering module is further provided for filtering noise in the dc input voltage Vin input to the positive electrode of the backlight control module. As shown in fig. 13, the third filter module takes the third filter capacitor C5 as an example, one end of the third filter capacitor C5 is connected to the dc input voltage Vin, and the other end of the third filter capacitor C5 is grounded.
In some embodiments, the display device further includes a second diode Dn; the positive pole of the second diode Dn is connected with the second end of the energy storage element Cn, and the negative pole of the second diode Dn is connected with the first end of the energy storage element Cn. The fourth diode Dn is used for enabling the backlight control module and the negative electrode of the power supply interface to form a current loop, so that the situation that when the first voltage conversion module does not work, current flows through the first voltage conversion module to cause system misoperation or other abnormal conditions is prevented, and the effect of protecting the first voltage conversion module is achieved.
In some embodiments, fig. 14 is a schematic structural diagram of a level shifter circuit based on a power supply circuit of a charge pump module according to an embodiment of the present application. The charge pump module takes fig. 10 as an example, and the power supply principle is not described again. In some embodiments, fig. 15 is a schematic structural diagram of a level conversion circuit based on a flyback isolation transformer module power supply circuit according to an embodiment of the present application, where the flyback isolation transformer module uses fig. 12 as an example, and the power supply principle is not described again.
In some embodiments, the display device provided in this embodiment further includes: a main board; the main board is connected with the power supply interface, and the direct current input voltage is used for supplying power to the main board. Fig. 16 is a schematic diagram of a circuit structure for supplying power to a motherboard according to an embodiment of the present application. When the direct current input voltage is equal to the demand voltage of the main board, the direct current input voltage can be selected to directly supply power for the main board.
In some embodiments, the display device further comprises a second voltage conversion module; the second voltage conversion module is connected with the power supply interface and the main board and is used for outputting second voltage according to the direct current input voltage, wherein the second voltage is the required voltage of the main board. Fig. 17 is a schematic diagram of another circuit structure for supplying power to a motherboard according to an embodiment of the present application. When the direct current input voltage does not meet the requirement voltage of the main board, the second voltage conversion module can be used for carrying out DC-DC voltage conversion on the direct current input voltage. When the television power is high, in order to reduce the cable loss, the current can be reduced by increasing the voltage, so that the dc input voltage is higher than the required voltage of the motherboard. In some embodiments, the second voltage conversion module may employ buck, boost-buck, etc. circuits, since a motherboard typically requires a fixed voltage.
The embodiment of the application also provides a display control method which is applied to the display device and comprises the following steps: receiving a feedback signal, wherein the feedback signal is generated by a backlight control module and is sent by the feedback module; based on the feedback signal, the first voltage is adjusted to adjust the required voltage of the backlight control module. In this embodiment, according to the feedback signal of the real-time current output by the backlight control module, the first voltage generated by the first voltage conversion module is adjusted, so as to adjust the required voltage of the backlight control module, so that the backlight control module works with rated current, and damage to components caused by excessive current flowing through the LED assemblies in the LED string is prevented.
The display device and the display control method provided by the embodiment of the application comprise the following steps: the backlight control module is used for controlling the light emitting diode to emit light, and the light emitting diode is used for lighting the screen of the display device; the power supply interface is used for receiving direct current input voltage provided by the external adapter; the first voltage conversion module is used for generating a first voltage according to the direct current input voltage; the energy storage element is connected with the first voltage conversion module and is used for storing first voltage; the energy storage element and the first voltage conversion module alternately output a first voltage; the negative electrode of the backlight control module is connected with a first voltage which is used as a negative reference voltage of the backlight control module; the positive electrode of the backlight control module is connected with the direct current input voltage; the sum of the absolute value of the direct current input voltage and the absolute value of the first voltage is equal to the required voltage of the backlight control module; and the feedback module is used for sending a feedback signal generated by the backlight control module to the first voltage conversion module, and the feedback signal is used for indicating the first voltage conversion module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
The embodiment of the application is provided with a power supply interface connected with the external adapter, and receives direct-current input voltage so as to adapt to the power supply mode of the external adapter; the first voltage generated by the direct current input voltage is used as a negative reference voltage of the backlight control module, and the direct current input voltage connected with the positive electrode of the backlight control module forms stepped power supply, so that the heat loss is reduced; the energy storage element is utilized to realize continuous power supply for the backlight control module; the power supply voltage of the backlight control module is timely adjusted through real-time feedback, so that the light emitting diode works stably.
Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.
It is to be understood that the application is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims (10)

1. A display device, comprising:
the backlight control module is used for controlling the light emitting diode to emit light, and the light emitting diode is used for lighting the screen of the display device;
the power supply interface is used for receiving direct current input voltage provided by the external adapter;
the first voltage conversion module is used for generating a first voltage according to the direct current input voltage; the energy storage element is connected with the first voltage conversion module and is used for storing the first voltage; the energy storage element and the first voltage conversion module alternately output the first voltage;
the negative electrode of the backlight control module is connected with the first voltage, and the first voltage is used as a negative reference voltage of the backlight control module; the positive electrode of the backlight control module is connected with the direct-current input voltage; the sum of the absolute value of the direct current input voltage and the absolute value of the first voltage is equal to the required voltage of the backlight control module;
and the feedback module is used for sending a feedback signal generated by the backlight control module to the first voltage conversion module, and the feedback signal is used for indicating the first voltage conversion module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
2. The apparatus of claim 1, wherein the first voltage conversion module comprises: a charge pump module;
the charge pump module is used for generating the first voltage in a charging state; and in a discharge state, providing the first voltage to a negative electrode of the backlight control module;
the first end of the energy storage element is connected with the positive output end of the charge pump module and grounded; the second end of the energy storage element is connected with the negative output end of the charge pump module; the energy storage element is used for storing the first voltage when the charge pump module discharges; and providing the first voltage to a negative electrode of the backlight control module when the charge pump module is charged;
the feedback signal is used for indicating the charge pump module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
3. The apparatus of claim 1, wherein the first voltage conversion module comprises: a flyback isolation transformer module;
the flyback isolation voltage transformation module is used for generating the first voltage by the secondary winding when the primary winding is conducted and transmitting the first voltage to the negative electrode of the backlight control module;
The first end of the energy storage element is connected with the forward output end of the flyback isolation transformer module and grounded; the second end of the energy storage element is connected with the negative output end of the flyback isolation transformer module; the energy storage element is used for storing the first voltage when the primary winding is conducted; and when the primary winding is cut off, providing the first voltage to the negative electrode of the backlight control module;
the feedback signal is used for indicating the flyback isolation voltage transformation module to adjust the first voltage so as to adjust the required voltage of the backlight control module.
4. The apparatus of claim 2, wherein the charge pump module comprises: the first controller, the first energy storage capacitor, the first switch, the second switch, the third switch and the fourth switch;
the first end of the first switch is connected with the direct-current input voltage, and the second end of the first switch is connected with the first end of the second switch; the second end of the second switch is used as a forward output end of the charge pump module, is connected with the first end of the energy storage element and is grounded;
the first end of the first energy storage capacitor is connected with the second end of the first switch and the first end of the second switch, and the second end of the first energy storage capacitor is connected with the first end of the third switch and the first end of the fourth switch; the second end of the fourth switch is grounded;
The second end of the third switch is used as a negative output end of the charge pump module, is connected with the second end of the energy storage element and outputs the first voltage;
the first controller is connected with the control ends of the first switch, the second switch, the third switch and the fourth switch and is used for adjusting the first voltage by controlling the switching frequencies of the first switch, the second switch, the third switch and the fourth switch according to the feedback signal;
the first switch and the second switch are different in switch state, and the first switch and the fourth switch are simultaneously disconnected or connected; the second switch and the third switch are simultaneously opened or closed.
5. The apparatus of claim 3, wherein the flyback isolation transformer module comprises: a primary winding, a secondary winding, a first diode, a second controller and a fifth switch;
the first end of the primary winding is connected with the direct current input voltage, the second end of the primary winding is connected with the first end of the fifth switch, and the second end of the fifth switch is grounded;
the secondary winding is coupled with the primary winding, and a first end of the secondary winding is connected with the positive electrode of the first diode; the negative electrode of the first diode is used as a positive output end of the flyback isolation transformer module, is connected with the first end of the energy storage element and is grounded;
The second end of the secondary winding is used as a negative output end of the flyback isolation transformer module, is connected with the second end of the energy storage element and outputs the first voltage;
the second controller is connected with the control end of the fifth switch and is used for adjusting the first voltage by controlling the switching frequency of the fifth switch according to the feedback signal.
6. The apparatus of any of claims 2-5, wherein the feedback module comprises a level shifting circuit;
the level conversion circuit receives a first feedback signal output by the backlight control module, converts the first feedback signal into a second feedback signal, and outputs the second feedback signal to the first voltage conversion module; wherein the reference voltages of the first feedback signal and the second feedback signal are different.
7. The apparatus of claim 1, wherein the apparatus further comprises: a second diode;
the positive pole of the second diode is connected with the second end of the energy storage element, and the negative pole of the second diode is connected with the first end of the energy storage element.
8. The apparatus of claim 1, wherein the apparatus further comprises: a main board;
The main board is connected with the power supply interface, and the direct current input voltage is used for supplying power to the main board.
9. The apparatus of claim 8, further comprising a second voltage conversion module;
the second voltage conversion module is connected with the power supply interface and the main board and is used for outputting a second voltage according to the direct current input voltage, wherein the second voltage is the required voltage of the main board.
10. A display control method, applied to the display device according to any one of claims 1 to 9,
the display control method includes:
receiving a feedback signal, wherein the feedback signal is generated by the backlight control module and is sent by the feedback module;
and adjusting the first voltage based on the feedback signal to adjust the required voltage of the backlight control module.
CN202210421396.1A 2021-12-14 2022-04-21 Display device and display control method Pending CN116978312A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CN202210421396.1A CN116978312A (en) 2022-04-21 2022-04-21 Display device and display control method
PCT/CN2022/114035 WO2023109168A1 (en) 2021-12-14 2022-08-22 Display device and display control method
CN202280067560.1A CN118076995A (en) 2021-12-14 2022-08-22 Display device and display control method
PCT/CN2022/121412 WO2023201988A1 (en) 2022-04-19 2022-09-26 Display apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210421396.1A CN116978312A (en) 2022-04-21 2022-04-21 Display device and display control method

Publications (1)

Publication Number Publication Date
CN116978312A true CN116978312A (en) 2023-10-31

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210421396.1A Pending CN116978312A (en) 2021-12-14 2022-04-21 Display device and display control method

Country Status (1)

Country Link
CN (1) CN116978312A (en)

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