WO2014146308A1 - 背光驱动板以及液晶显示器 - Google Patents

背光驱动板以及液晶显示器 Download PDF

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Publication number
WO2014146308A1
WO2014146308A1 PCT/CN2013/073252 CN2013073252W WO2014146308A1 WO 2014146308 A1 WO2014146308 A1 WO 2014146308A1 CN 2013073252 W CN2013073252 W CN 2013073252W WO 2014146308 A1 WO2014146308 A1 WO 2014146308A1
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WIPO (PCT)
Prior art keywords
backlight
controlled switch
driving board
mode switching
liquid crystal
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PCT/CN2013/073252
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English (en)
French (fr)
Inventor
张华�
张先明
杨翔
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深圳市华星光电技术有限公司
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Application filed by 深圳市华星光电技术有限公司 filed Critical 深圳市华星光电技术有限公司
Priority to DE112013006696.3T priority Critical patent/DE112013006696B4/de
Priority to US13/877,334 priority patent/US9207458B2/en
Priority to JP2015560517A priority patent/JP6122568B2/ja
Priority to GB1513064.4A priority patent/GB2524213B/en
Publication of WO2014146308A1 publication Critical patent/WO2014146308A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/20—Controlling the colour of the light
    • 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
    • G09G3/34—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 by control of light from an independent source
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/46—Details of LED load circuits with an active control inside an LED matrix having LEDs disposed in parallel lines

Definitions

  • the present invention relates to the field of liquid crystal display, and in particular to a backlight driving board and a liquid crystal display including the same.
  • Such a liquid crystal display includes a liquid crystal driving board and a backlight driving board, and the liquid crystal driving board controls the backlight to emit light through the backlight driving board.
  • the backlight driver board and the liquid crystal driver board need strict synchronization to ensure good viewing performance.
  • the backlight driving board of the prior art comprises a constant current driving chip, and the constant current driving chip needs to receive multiple control signals from the liquid crystal driving board, and the multi-channel control signal must include: a chip selection signal, a clock signal, a data signal, a synchronization signal, The common ground signal and the 3D/2D switching signal, the prior art backlight driving board has too many controlled signals, and is easy to work poorly due to external interference.
  • the technical problem to be solved by the present invention is to provide a backlight driving board and a liquid crystal display, which can reduce the signal line between the backlight driving board and the liquid crystal driving board, thereby preventing the backlight driving board from being easily interfered by the outside due to excessive signal lines.
  • the operational stability of the liquid crystal display can be improved.
  • a technical solution adopted by the present invention is to provide a backlight driving board for driving a plurality of backlights, wherein the backlight driving board comprises: a microprocessor and a constant current driving chip.
  • the microprocessor is configured to receive a display mode switching signal and a synchronization signal from the liquid crystal driving board, and generate a first pulse width modulation signal respectively corresponding to the backlight according to the display mode switching signal and the synchronization signal, and the backlight driving board and the liquid crystal driving board are collectively Ground connection.
  • the constant current driving chip is configured to control a duty ratio of a current flowing through the backlight according to the first pulse width modulation signal.
  • the constant current driving chip further receives the display mode switching signal, and controls the amplitude of the current flowing through the backlight according to the display mode switching signal.
  • the constant current driving chip includes a comparator corresponding to the backlight and a first controlled switch respectively, and the non-inverting input end of the comparator is connected to the display mode switching signal, and the inverting input end of the comparator is connected to the first controlled switch.
  • One end is grounded via a resistor, and the output end of the comparator is connected to the control end of the first controlled switch, and the second end of the first controlled switch is connected to one end of the backlight, and the control end of the first controlled switch is connected to the first pulse
  • the wide modulation signal, the display mode switching signal produces different voltage values at the non-inverting input of the comparator in different display modes to control the magnitude of the current flowing through the backlight.
  • the backlight driving board further includes a power module, and the power module is connected to the other end of the backlight to supply power to the backlight.
  • the backlight driving board includes a microprocessor and a constant current driving chip.
  • the microprocessor is configured to receive the display mode switching signal and the synchronization signal from the liquid crystal driving board, and generate a first pulse width modulation signal respectively corresponding to the backlight according to the display mode switching signal and the synchronization signal.
  • the constant current driving chip is configured to control an operating state of the corresponding backlight according to the first pulse width modulation signal.
  • the constant current driving chip controls the duty ratio of the current flowing through the backlight according to the first pulse width modulation signal.
  • the constant current driving chip further receives the display mode switching signal, and controls the amplitude of the current flowing through the backlight according to the display mode switching signal.
  • the constant current driving chip includes a comparator corresponding to the backlight and a first controlled switch respectively, and the non-inverting input end of the comparator is connected to the display mode switching signal, and the inverting input end of the comparator is connected to the first controlled switch.
  • One end is grounded via a resistor, and the output end of the comparator is connected to the control end of the first controlled switch, and the second end of the first controlled switch is connected to one end of the backlight, and the control end of the first controlled switch is connected to the first pulse
  • the wide modulation signal, the display mode switching signal produces different voltage values at the non-inverting input of the comparator in different display modes to control the magnitude of the current flowing through the backlight.
  • the backlight driving board further includes a power module, and the power module is connected to the other end of the backlight to supply power to the backlight.
  • the power module includes an inductor, a second controlled switch, a rectifier diode, and a capacitor.
  • One end of the inductor is connected to the power voltage, and the first end of the second controlled switch is connected to the other end of the inductor, and the second end of the second controlled switch.
  • Grounding the positive pole of the rectifier diode is connected to the other end of the inductor, the cathode of the rectifier diode is connected to the other end of the backlight, one end of the capacitor is connected between the rectifier diode and the backlight, and the other end of the capacitor is grounded, and the second controlled switch is The control terminal is connected to the second pulse width modulation signal.
  • the backlight is an LED string, and the anode of the LED string is connected to the power module, and the cathode of the LED string is connected to the second end of the first controlled switch.
  • the backlight driving board and the liquid crystal driving board are connected in common.
  • the display mode switching signal is a 2D/3D switching signal.
  • a liquid crystal display including a liquid crystal driving board, a plurality of backlights, and a backlight driving board
  • the backlight driving board includes: a microprocessor and a constant current driving chip.
  • the microprocessor is configured to receive the display mode switching signal and the synchronization signal from the liquid crystal driving board, and generate a first pulse width modulation signal respectively corresponding to the backlight according to the display mode switching signal and the synchronization signal.
  • the constant current driving chip is configured to control an operating state of the corresponding backlight according to the first pulse width modulation signal.
  • the constant current driving chip controls the duty ratio of the current flowing through the backlight according to the first pulse width modulation signal.
  • the constant current driving chip further receives the display mode switching signal, and controls the amplitude of the current flowing through the backlight according to the display mode switching signal.
  • the constant current driving chip includes a comparator corresponding to the backlight and a first controlled switch respectively, and the non-inverting input end of the comparator is connected to the display mode switching signal, and the inverting input end of the comparator is connected to the first controlled switch.
  • One end is grounded via a resistor, and the output end of the comparator is connected to the control end of the first controlled switch, and the second end of the first controlled switch is connected to one end of the backlight, and the control end of the first controlled switch is connected to the first pulse
  • the wide modulation signal, the display mode switching signal produces different voltage values at the non-inverting input of the comparator in different display modes to control the magnitude of the current flowing through the backlight.
  • the backlight driving board further includes a power module, and the power module is connected to the other end of the backlight to supply power to the backlight.
  • the power module includes an inductor, a second controlled switch, a rectifier diode, and a capacitor.
  • One end of the inductor is connected to the power voltage, and the first end of the second controlled switch is connected to the other end of the inductor, and the second end of the second controlled switch.
  • Grounding the positive pole of the rectifier diode is connected to the other end of the inductor, the cathode of the rectifier diode is connected to the other end of the backlight, one end of the capacitor is connected between the rectifier diode and the backlight, and the other end of the capacitor is grounded, and the second controlled switch is The control terminal is connected to the second pulse width modulation signal.
  • the backlight is an LED string, and the anode of the LED string is connected to the power module, and the cathode of the LED string is connected to the second end of the first controlled switch.
  • the backlight driving board of the present invention can generate a pulse width modulation signal to control the illumination of the backlight by providing a microprocessor, and can reduce the between the backlight driving board and the liquid crystal driving board.
  • the signal line can avoid the backlight driver board from being easily interfered by the outside due to too many signal lines, thereby improving the stability of the operation of the liquid crystal display.
  • FIG. 1 is a schematic block diagram of a liquid crystal display according to an embodiment of the present invention.
  • FIG. 2 is a schematic block diagram of a backlight driving board of an embodiment of the present invention.
  • FIG. 1 is a schematic block diagram of a liquid crystal display according to an embodiment of the present invention.
  • the liquid crystal display preferably includes a liquid crystal driving board 10, a backlight driving board 11, and a backlight 12.
  • the liquid crystal driving board 10 is configured to control the liquid crystal molecules in the liquid crystal panel (not shown) to be deflected according to the display content
  • the backlight driving board 11 is used to control the backlight 12 to emit light and cooperate with the liquid crystal panel driven by the liquid crystal driving board 10 to complete different operations. display effect.
  • the liquid crystal display requires the liquid crystal driving board 10 and the backlight driving board 11 to be strictly synchronized to achieve a better display effect. At the same time, it is necessary to control the backlight 12 to perform different actions according to different display modes.
  • the liquid crystal driving board 10 controls the backlight 12 to emit light to meet various display requirements by outputting the synchronization signal Vsync and the display mode switching signal T to the backlight driving board 11. Further, the liquid crystal driving board 10 and the backlight driving board 11 are commonly connected by a common ground GND. It should be understood that in the embodiment, the number of the backlights 12 is plural, and the backlight 12 is preferably a LED string. In other embodiments, the backlight 12 may also be other light-emitting elements.
  • the display mode switching signal T is a 2D/3D switching signal.
  • FIG. 2 is a schematic block diagram of a backlight driving board according to an embodiment of the present invention.
  • the backlight driving board 11 preferably includes a microprocessor 111, a constant current driving chip 112, a power supply module 114, and a resistor R.
  • the microprocessor 111 is configured to receive the display mode switching signal T and the synchronization signal Vsync from the liquid crystal driving board 10, and generate first pulse width modulation signals PWM1-PWMn corresponding to the backlight 12 respectively according to the display mode switching signal T and the synchronization signal Vsync. . After receiving the display mode switching signal T, the microprocessor 111 calls the internal encoding program to output different first pulse width modulation signals PWM1 in the 2D and 3D display modes, respectively.
  • the microprocessor 111 is connected to the liquid crystal driving board 10 through two signal lines. A common ground line GND is also connected between the microprocessor 111 and the liquid crystal drive board 10. Therefore, there are only three connections between the liquid crystal driving board 10 and the microprocessor 111, that is, between the liquid crystal driving board 10 and the backlight driving board 11, which can avoid being easily disturbed by the outside due to too many wiring lines.
  • the constant current driving chip 112 includes a comparator A and a first controlled switch M1 respectively corresponding to the backlight 12.
  • the non-inverting input of the comparator A is connected to the display mode switching signal T, and the inverting input of the comparator A is connected to the first end of the first controlled switch M1 and is grounded via the resistor R.
  • the output end of the comparator A is connected to the control end of the first controlled switch M1, the second end of the first controlled switch M1 is connected to the cathode of the backlight 12, and the control end of the first controlled switch M1 is connected to the first pulse width modulation signal.
  • the display mode switching signal T produces different voltage values at the non-inverting input of comparator A in different display modes to control the magnitude of the current flowing through the backlight 12.
  • the magnitude of the current flowing through the backlight 12 is adjusted in the manner described above.
  • the amplitude of the current flowing through the backlight 12 in the 2D display mode is different from that in the 3D display mode, and the display mode switching signal T can satisfy the different amplitudes of the current of the backlight 12 by changing the voltage value.
  • the first controlled switch M1 is preferably an NMOS transistor, the first end of the first controlled switch M1 is a drain, the second end is a source, and the control end is a gate. In other embodiments, The first controlled switch M1 can also be other components.
  • the constant current driving chip 112 also controls the duty ratio of the current flowing through the backlight 12 in accordance with the first pulse width modulation signals PWM1-PWMn.
  • the first pulse width modulation signal PWM1-PWMn is a square wave digital signal generated by the microprocessor 111 according to the display mode switching signal T and the synchronization signal Vsync.
  • the first pulse width signal PWM1-PWMn controls the first end and the second end of the first controlled switch M1 connected thereto to be turned on when the level is high, and is turned off when the level is low. In the above manner, the first pulse width modulation signal PWM1-PWMn controls the duty ratio of the current flowing through the backlight 12.
  • the duty ratio of the current of the backlight 12 is fixed to 20% in the 3D mode, and the duty ratio of the current can be arbitrarily adjusted in the 2D display mode. In other embodiments, the current of the backlight 12 is occupied.
  • the adjustment range of the air ratio can also be other values.
  • the power module 113 preferably includes an inductor L, a second controlled switch M2, a rectifier diode D, and a capacitor C.
  • One end of the inductor L is connected to the power supply voltage
  • the first end of the second controlled switch M2 is connected to the other end of the inductor L
  • the second end of the second controlled switch M2 is grounded.
  • the anode of the rectifier diode D is connected to the other end of the inductor L
  • the cathode of the rectifier diode D is connected to the anode of the backlight 12.
  • the power module 113 is used to power the backlight 12 . It should be noted that the power module 113 may also be composed of other components, and other components may be connected. In this embodiment, the power supply voltage is preferably 24V. In other embodiments, the power supply voltage may also be other voltage values. In this embodiment, the second controlled switch M2 is an NMOS transistor. In other embodiments, the second controlled switch M2 may also be other components.
  • the backlight driving board of the present invention can generate a pulse width modulation signal to control the illumination of the backlight, and can reduce the signal line between the backlight driving board and the liquid crystal driving board, thereby avoiding the backlight driving board. Due to excessive signal lines, it is susceptible to external interference, which in turn improves the operational stability of the liquid crystal display.

Abstract

一种用于驱动多个背光源（12）的背光驱动板（11）包括微处理器（111）和恒流驱动芯片（112）。微处理器（111）用于从液晶驱动板（10）接收显示模式切换信号（Vsync）和同步信号（T），并根据显示模式切换信号（Vsync）和同步信号（T）产生分别对应于背光源（12）的第一脉宽调制信号（PWMl-PWMn）。恒流驱动芯片（112）用于根据第一脉宽调制信号（PWM1-PWMn）控制对应的背光源（12）的工作状态。由此减少背光驱动板（11）与液晶驱动板（10）之间的信号线，进而提升工作稳定性。

Description

背光驱动板以及液晶显示器
【技术领域】
本发明涉及液晶显示领域，特别是涉及一种背光驱动板以及包括该背光驱动板的液晶显示器。
【背景技术】
随着科学技术的发展，同时具备3D和2D显示功能的液晶显示器在人们日常生活中越来越常见。此类液晶显示器包括液晶驱动板和背光驱动板，液晶驱动板通过背光驱动板控制背光源发光。背光驱动板与液晶驱动板需要严格的同步才能保证良好的观看效果。现有技术的背光驱动板包括恒流驱动芯片，恒流驱动芯片需要接收来至液晶驱动板的多路控制信号，多路控制信号必须包括：片选信号、时钟信号、数据信号、同步信号、共地信号以及3D/2D切换信号，现有技术的背光驱动板受控信号过多，容易因外界的干扰而造成工作稳定性差。
因此，需要提供一种背光驱动板以及液晶显示器，以解决上述问题。
【发明内容】
本发明主要解决的技术问题是提供一种背光驱动板以及液晶显示器，能够减少背光驱动板与液晶驱动板之间的信号线，从而能够避免背光驱动板因信号线过多而容易受外界干扰，进而能够提升液晶显示器的工作稳定性。
为解决上述技术问题，本发明采用的一个技术方案是：提供一种背光驱动板，用于驱动多个背光源，其中，背光驱动板包括：微处理器和恒流驱动芯片。微处理器用于从液晶驱动板接收显示模式切换信号和同步信号，并根据显示模式切换信号和同步信号产生分别对应于背光源的第一脉宽调制信号，背光驱动板与液晶驱动板之间共地连接。恒流驱动芯片用于根据第一脉宽调制信号控制流经背光源的电流的占空比。
其中，恒流驱动芯片进一步接收显示模式切换信号，并根据显示模式切换信号控制流经背光源的电流的幅值。
其中，恒流驱动芯片包括分别对应于背光源的比较器和第一受控开关，比较器的正相输入端连接显示模式切换信号，比较器的反相输入端连接第一受控开关的第一端并经一电阻接地，比较器的输出端连接第一受控开关的控制端，第一受控开关的第二端连接背光源的一端，第一受控开关的控制端连接第一脉宽调制信号，显示模式切换信号在不同显示模式于比较器的正相输入端产生不同的电压值，以控制流经背光源的电流的幅值。
其中，背光驱动板还包括电源模块，电源模块连接背光源的另一端，以对背光源进行供电。
为解决上述技术问题，本发明采用的另一个技术方案是：提供一种背光驱动板，用于驱动多个背光源。该背光驱动板包括微处理器和恒流驱动芯片。微处理器用于从液晶驱动板接收显示模式切换信号和同步信号，并根据显示模式切换信号和同步信号产生分别对应于背光源的第一脉宽调制信号。恒流驱动芯片用于根据第一脉宽调制信号控制对应的背光源的工作状态。
其中，恒流驱动芯片根据第一脉宽调制信号控制流经背光源的电流的占空比。
其中，恒流驱动芯片进一步接收显示模式切换信号，并根据显示模式切换信号控制流经背光源的电流的幅值。
其中，恒流驱动芯片包括分别对应于背光源的比较器和第一受控开关，比较器的正相输入端连接显示模式切换信号，比较器的反相输入端连接第一受控开关的第一端并经一电阻接地，比较器的输出端连接第一受控开关的控制端，第一受控开关的第二端连接背光源的一端，第一受控开关的控制端连接第一脉宽调制信号，显示模式切换信号在不同显示模式下于比较器的正相输入端产生不同的电压值，以控制流经背光源的电流的幅值。
其中，背光驱动板还包括电源模块，电源模块连接背光源的另一端，以对背光源进行供电。
其中，电源模块包括电感、第二受控开关、整流二极管以及电容，电感的一端连接电源电压，第二受控开关的第一端与电感的另一端连接，第二受控开关的第二端接地，整流二极管的正极与电感的另一端连接，整流二极管的负极与背光源的另一端连接，电容的一端接入整流二极管和背光源之间，电容的另一端接地，第二受控开关的控制端连接第二脉宽调制信号。
其中，背光源为LED串，LED串的正极与电源模块连接，LED串的负极与第一受控开关的第二端连接。
其中，背光驱动板与液晶驱动板之间共地连接。
其中，显示模式切换信号为2D/3D切换信号。
为解决上述技术问题，本发明采用的又一个技术方案是：提供一种液晶显示器，包括液晶驱动板、多个背光源以及背光驱动板，背光驱动板包括：微处理器和恒流驱动芯片，微处理器用于从液晶驱动板接收显示模式切换信号和同步信号，并根据显示模式切换信号和同步信号产生分别对应于背光源的第一脉宽调制信号。恒流驱动芯片用于根据第一脉宽调制信号控制对应的背光源的工作状态。
其中，恒流驱动芯片根据第一脉宽调制信号控制流经背光源的电流的占空比。
其中，恒流驱动芯片进一步接收显示模式切换信号，并根据显示模式切换信号控制流经背光源的电流的幅值。
其中，恒流驱动芯片包括分别对应于背光源的比较器和第一受控开关，比较器的正相输入端连接显示模式切换信号，比较器的反相输入端连接第一受控开关的第一端并经一电阻接地，比较器的输出端连接第一受控开关的控制端，第一受控开关的第二端连接背光源的一端，第一受控开关的控制端连接第一脉宽调制信号，显示模式切换信号在不同显示模式于比较器的正相输入端产生不同的电压值，以控制流经背光源的电流的幅值。
其中，背光驱动板还包括电源模块，电源模块连接背光源的另一端，以对背光源进行供电。
其中，电源模块包括电感、第二受控开关、整流二极管以及电容，电感的一端连接电源电压，第二受控开关的第一端与电感的另一端连接，第二受控开关的第二端接地，整流二极管的正极与电感的另一端连接，整流二极管的负极与背光源的另一端连接，电容的一端接入整流二极管和背光源之间，电容的另一端接地，第二受控开关的控制端连接第二脉宽调制信号。
其中，背光源为LED串，LED串的正极与电源模块连接，LED串的负极与第一受控开关的第二端连接。
本发明的有益效果是：区别于现有技术的情况，本发明的背光驱动板通过设置微处理器来产生脉宽调制信号控制背光源的发光，能够减少背光驱动板与液晶驱动板之间的信号线，从而能够避免背光驱动板因信号线过多而容易受外界干扰，进而能够提升液晶显示器工作的稳定性。
【附图说明】
图1是本发明实施例的液晶显示器的示意框图；
图2是本发明实施例的背光驱动板的示意框图。
【具体实施方式】
下面结合附图和实施例对本发明进行详细说明。
请参阅图1，图1是本发明实施例的液晶显示器的示意框图。在本实施例中，液晶显示器优选地包括：液晶驱动板10、背光驱动板11以及背光源12。液晶驱动板10用于根据显示内容控制液晶面板（未图示）中的液晶分子进行偏转，背光驱动板11用于控制背光源12发光并配合液晶驱动板10所驱动的液晶面板共同完成不同的显示效果。液晶显示器需要液晶驱动板10和背光驱动板11严格同步，才能达到较好的显示效果。同时，需要根据不同的显示模式控制背光源12进行不同的动作。
在本实施例中，液晶驱动板10通过输出同步信号Vsync和显示模式切换信号T至背光驱动板11，进而控制背光源12发光以满足各种显示需求。进一步，液晶驱动板10与背光驱动板11通过共地线GND进行共地连接。应理解，在本实施例中，背光源12数量为多个，背光源12优选为LED串，在其他实施例中，背光源12也可以是其他发光元件。在本实施例中，显示模式切换信号T为2D/3D切换信号。
请进一步参阅图2，图2是本发明实施例的背光驱动板的示意框图。背光驱动板11优选地包括：微处理器111、恒流驱动芯片112、电源模块114以及电阻R。
微处理器111用于从液晶驱动板10接收显示模式切换信号T和同步信号Vsync，并根据显示模式切换信号T和同步信号Vsync产生分别对应于背光源12的第一脉宽调制信号PWM1-PWMn。微处理器111接收到显示模式切换信号T后，调用内部编码程序，分别在2D和3D显示模式下输出不同的第一脉宽调制信号PWM1。微处理器111通过两根信号线连接液晶驱动板10。微处理器111和液晶驱动板10之间还连接有共地线GND。因此，液晶驱动板10与微处理器111之间，即液晶驱动板10与背光驱动板11之间只有三根连线，可以避免因连线过多而导致容易被外界干扰。
恒流驱动芯片112包括分别数量对应于背光源12的比较器A和第一受控开关M1。比较器A的正相输入端连接显示模式切换信号T，比较器A的反相输入端连接第一受控开关M1的第一端并经电阻R接地。比较器A的输出端连接第一受控开关M1的控制端，第一受控开关M1的第二端连接背光源12的阴极，第一受控开关M1的控制端连接第一脉宽调制信号PWM1-PWMn中的对应一个。显示模式切换信号T在不同显示模式下于比较器A的正相输入端产生不同电压值，以控制流经背光源12的电流的幅值。比较器A的反相输入端反馈R上电压V1，比较器A对正相输出端的显示模式切换信号产生的电压V2与电压V1进行多次比较，输出不同结果至第一受控开关M1，达到稳定状态时，V1=V2。通过上述方式调节流经背光源12的电流的幅值。2D显示模式与3D显示模式下流过背光源12的电流的幅值不同，显示模式切换信号T通过改变电压值可以满足背光源12的电流不同幅值的要求。在本实施例中，第一受控开关M1优选为NMOS管，第一受控开关M1的第一端为漏极，第二端为源极，控制端为栅极，在其他实施例中，第一受控开关M1也可以是其他的元器件。
恒流驱动芯片112还根据第一脉宽调制信号PWM1-PWMn控制流经背光源12的电流的占空比。第一脉宽调制信号PWM1-PWMn为微处理器111根据显示模式切换信号T和同步信号Vsync产生的方波数字信号。第一脉宽信号PWM1-PWMn在高电平时控制与其连接的第一受控开关M1的第一端与第二端导通，低电平时截止。通过上述方式，第一脉宽调制信号PWM1-PWMn控制流经背光源12的电流的占空比，占空比越大，流经背光源12的平均电流越大，占空比越小，流过背光源12的平均电流越小，从而达到控制背光源12亮暗的目的。在本实施例中，在3D模式下背光源12的电流的占空比固定为20%，在2D显示模式下电流的占空比能够任意调节，在其他实施例中，背光源12的电流占空比的调节范围也可以是其他值。
电源模块113优选地包括电感L、第二受控开关M2、整流二极管D以及电容C。电感L的一端连接电源电压，第二受控开关M2的第一端与电感L的另一端连接，第二受控开关M2的第二端接地。整流二极管D的正极与电感L的另一端连接，整流二极管D的负极与背光源12的阳极连接。电容C的一端接入整流二极管D和背光源12之间，电容C的另一端接地，第二受控开关M2的控制端连接第二脉宽调制信号P。第二脉宽调制信号P由恒流驱动芯片112产生。电源模块113用于为背光源12供电。值得注意的是电源模块113也可以由其他的元器件组成，元器件之间也可以是其他的连接关系。在本实施例中，电源电压优选为24V，在其他实施例中，电源电压也可以是其他的电压值。在本实施例中，第二受控开关M2为NMOS管，在其他实施例中，第二受控开关M2也可以是其他元器件。
区别于现有技术，本发明的背光驱动板通过设置微处理器来产生脉宽调制信号控制背光源的发光，能够减少背光驱动板与液晶驱动板之间的信号线，从而能够避免背光驱动板因信号线过多而容易受外界干扰，进而能够提升液晶显示器的工作稳定性。
以上所述仅为本发明的实施方式，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (20)

  1. 一种背光驱动板，用于驱动多个背光源，其中，所述背光驱动板包括：
    微处理器，用于从液晶驱动板接收显示模式切换信号和同步信号，并根据所述显示模式切换信号和所述同步信号产生分别对应于所述背光源的第一脉宽调制信号，所述背光驱动板与所述液晶驱动板之间共地连接；
    恒流驱动芯片，用于根据所述第一脉宽调制信号控制流经所述背光源的电流的占空比。
  2. 根据权利要求1所述的背光驱动板，其中，所述恒流驱动芯片进一步接收所述显示模式切换信号，并根据所述显示模式切换信号控制流经所述背光源的电流的幅值。
  3. 根据权利要求2所述的背光驱动板，其中，所述恒流驱动芯片包括分别对应于所述背光源的比较器和第一受控开关，所述比较器的正相输入端连接所述显示模式切换信号，所述比较器的反相输入端连接所述第一受控开关的第一端并经一电阻接地，所述比较器的输出端连接所述第一受控开关的控制端，所述第一受控开关的第二端连接所述背光源的一端，所述第一受控开关的控制端连接所述第一脉宽调制信号，所述显示模式切换信号在不同显示模式于所述比较器的正相输入端产生不同的电压值，以控制流经所述背光源的电流的幅值。
  4. 根据权利要求3所述的背光驱动板，其中，所述背光驱动板还包括电源模块，所述电源模块连接所述背光源的另一端，以对所述背光源进行供电。
  5. 一种背光驱动板，用于驱动多个背光源，其中，所述背光驱动板包括：
    微处理器，用于从液晶驱动板接收显示模式切换信号和同步信号，并根据所述显示模式切换信号和所述同步信号产生分别对应于所述背光源的第一脉宽调制信号；
    恒流驱动芯片，用于根据所述第一脉宽调制信号控制对应的所述背光源的工作状态。
  6. 根据权利要求5所述的背光驱动板，其中，所述恒流驱动芯片根据所述第一脉宽调制信号控制流经所述背光源的电流的占空比。
  7. 根据权利要求6所述的背光驱动板，其中，所述恒流驱动芯片进一步接收所述显示模式切换信号，并根据所述显示模式切换信号控制流经所述背光源的电流的幅值。
  8. 根据权利要求7所述的背光驱动板，其中，所述恒流驱动芯片包括分别对应于所述背光源的比较器和第一受控开关，所述比较器的正相输入端连接所述显示模式切换信号，所述比较器的反相输入端连接所述第一受控开关的第一端并经一电阻接地，所述比较器的输出端连接所述第一受控开关的控制端，所述第一受控开关的第二端连接所述背光源的一端，所述第一受控开关的控制端连接所述第一脉宽调制信号，所述显示模式切换信号在不同显示模式于所述比较器的正相输入端产生不同的电压值，以控制流经所述背光源的电流的幅值。
  9. 根据权利要求8所述的背光驱动板，其中，所述背光驱动板还包括电源模块，所述电源模块连接所述背光源的另一端，以对所述背光源进行供电。
  10. 根据权利要求9所述的背光驱动板，其中，所述电源模块包括电感、第二受控开关、整流二极管以及电容，所述电感的一端连接电源电压，所述第二受控开关的第一端与所述电感的另一端连接，所述第二受控开关的第二端接地，所述整流二极管的正极与所述电感的另一端连接，所述整流二极管的负极与所述背光源的另一端连接，所述电容的一端接入所述整流二极管和所述背光源之间，所述电容的另一端接地，所述第二受控开关的控制端连接第二脉宽调制信号。
  11. 根据权利要求9所述的背光驱动板，其中，所述背光源为LED串，所述LED串的正极与所述电源模块连接，所述LED串的负极与所述第一受控开关的第二端连接。
  12. 根据权利要求5所述的背光驱动板，其中，所述背光驱动板与所述液晶驱动板之间共地连接。
  13. 根据权利要求5所述的背光驱动板，其中，所述显示模式切换信号为2D/3D切换信号。
  14. 一种液晶显示器，其中，所述液晶显示器包括液晶驱动板、多个背光源以及背光驱动板，所述背光驱动板包括：
    微处理器，用于从液晶驱动板接收显示模式切换信号和同步信号，并根据所述显示模式切换信号和所述同步信号产生分别对应于所述背光源的第一脉宽调制信号；
    恒流驱动芯片，用于根据所述第一脉宽调制信号控制对应的所述背光源的工作状态。
  15. 根据权利要求14所述的液晶显示器，其中，所述恒流驱动芯片根据所述第一脉宽调制信号控制流经所述背光源的电流的占空比。
  16. 根据权利要求15所述的液晶显示器，其中，所述恒流驱动芯片进一步接收所述显示模式切换信号，并根据所述显示模式切换信号控制流经所述背光源的电流的幅值。
  17. 根据权利要求16所述的液晶显示器，其中，所述恒流驱动芯片包括分别对应于所述背光源的比较器和第一受控开关，所述比较器的正相输入端连接所述显示模式切换信号，所述比较器的反相输入端连接所述第一受控开关的第一端并经一电阻接地，所述比较器的输出端连接所述第一受控开关的控制端，所述第一受控开关的第二端连接所述背光源的一端，所述第一受控开关的控制端连接所述第一脉宽调制信号，所述显示模式切换信号在不同显示模式于所述比较器的正相输入端产生不同的电压值，以控制流经所述背光源的电流的幅值。
  18. 根据权利要求17所述的液晶显示器，其中，所述背光驱动板还包括电源模块，所述电源模块连接所述背光源的另一端，以对所述背光源进行供电。
  19. 根据权利要求18所述的液晶显示器，其中，所述电源模块包括电感、第二受控开关、整流二极管以及电容，所述电感的一端连接电源电压，所述第二受控开关的第一端与所述电感的另一端连接，所述第二受控开关的第二端接地，所述整流二极管的正极与所述电感的另一端连接，所述整流二极管的负极与所述背光源的另一端连接，所述电容的一端接入所述整流二极管和所述背光源之间，所述电容的另一端接地，所述第二受控开关的控制端连接第二脉宽调制信号。
  20. 根据权利要求18所述的液晶显示器，其中，所述背光源为LED串，所述LED串的正极与所述电源模块连接，所述LED串的负极与所述第一受控开关的第二端连接。
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