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WO2015089924A1 - Led backlight driving circuit and liquid crystal television set - Google Patents

Led backlight driving circuit and liquid crystal television set Download PDF

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Publication number
WO2015089924A1
WO2015089924A1 PCT/CN2014/070523 CN2014070523W WO2015089924A1 WO 2015089924 A1 WO2015089924 A1 WO 2015089924A1 CN 2014070523 W CN2014070523 W CN 2014070523W WO 2015089924 A1 WO2015089924 A1 WO 2015089924A1
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Prior art keywords
bjt
mos
field effect
resistor
effect transistor
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French (fr)
Chinese (zh)
Inventor
张先明
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TCL China Star Optoelectronics Technology Co Ltd
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Shenzhen China Star Optoelectronics Technology Co Ltd
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Publication of WO2015089924A1 publication Critical patent/WO2015089924A1/en
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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
    • G09G3/34—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
    • G09G3/3406—Control of illumination 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]
    • H05B45/30—Driver circuits
    • H05B45/395—Linear regulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

  • the present invention relates to the field of electronic technologies, and in particular, to an LED backlight driving circuit and a liquid crystal television. Background technique
  • the LED driver integrated circuit In the current LCD backlight driver, the LED driver integrated circuit generally needs to detect the voltage at the negative end of the Light Bar, but the backlight is dimmed during PWM (Pulse Width Modulation) dimming or 3D.
  • the voltage at the negative end of the source Light Bar is generally large, generally 30 ⁇ 50V. If the output voltage is high, the voltage at the negative end of the Light Bar may even reach 70 to 80 volts, but the general LED Driver IC detects the Pin.
  • the withstand voltage is generally 30V ⁇ 40V, so it is common to add an isolated FET MOS at the negative end of the Light Bar to turn off the MOS when the negative voltage of the Light Bar is large, to prevent damage to the IC.
  • the invention provides an LED backlight driving circuit and a liquid crystal television set, wherein the LED backlight driving circuit comprises: a backlight source, in order to solve the technical problem that the efficiency of the MOS tube in the prior art LED backlight driving circuit is reduced and the loss is increased.
  • a negative terminal a driving IC, a bipolar junction transistor BJT, a field effect transistor MOS, a resistor; a control output of the driving IC is connected to a source of the field effect transistor MOS; and a gate connection of the field effect transistor MOS Turning off the reference voltage, the drain of which is connected to the base of the bipolar junction transistor BJT; the emitter of the BJT is connected to the feedback input of the driver IC Connected to and grounded via the resistor; the collector of the BJT is connected to the negative terminal of the backlight.
  • the bipolar junction transistor BJT transistor is a PNP transistor.
  • the field effect transistor MOS is an N-channel MOS transistor.
  • the turn-off reference voltage is 12V.
  • the resistor is a first resistor and a second resistor connected in parallel.
  • the present invention also provides a liquid crystal television set comprising: a backlight negative terminal, a driving IC, a bipolar junction transistor BJT, a field effect transistor MOS, a resistor; a control output terminal of the driving IC and the field effect transistor MOS a source connection; a gate of the field effect transistor MOS is connected to turn off a reference voltage, a drain thereof is connected to a base of the bipolar junction transistor BJT; and a feedback input of the emitter of the BJT and the driving IC The terminal is connected and grounded via the resistor; the collector of the BJT is connected to the negative terminal of the backlight.
  • the bipolar junction transistor BJT transistor is a PNP transistor.
  • the field effect transistor MOS is an N-channel MOS transistor.
  • the turn-off reference voltage is 12V.
  • the resistor is a first resistor and a second resistor connected in parallel.
  • an isolation MOS is disposed between the B pole of the BJT and the driving IC, and the feedback voltage is not conducted to the IC during normal operation, and during the dimming process, the backlight module BLU is turned off, and the backlight is negative.
  • the voltage of VLED- will be relatively high.
  • the PN transistor in the BJT tube of the bipolar junction transistor is turned on to the MOS transistor to turn off the MOS transistor, thereby preventing the high voltage of the VLED- terminal from breaking down the driving IC.
  • FIG. 1 is a circuit diagram of an LED backlight driving circuit of the present invention. detailed description
  • the present invention provides an LED backlight driving circuit including a backlight negative terminal, a driving IC, a bipolar junction transistor BJT, a field effect transistor MOS, a resistor; a control output terminal of the driving IC and the a source of the field effect transistor MOS is connected; a gate of the field effect transistor MOS is connected to turn off a reference voltage, a drain thereof is connected to a base of the bipolar junction transistor BJT; and an emitter of the BJT is The feedback input of the driver IC is connected and grounded via the resistor; the collector of the BJT is connected to the negative terminal of the backlight.
  • the turn-off reference voltage is 12V, which is merely an example.
  • the resistor connected to the emitter of the BJT is specifically a first resistor R1 and a second resistor R2.
  • FIG. 1 which is a specific circuit diagram of the LED backlight driving circuit of the present invention, the technical solution of the present invention will be described in detail below with reference to FIG. 1 and specific embodiments.
  • the LED backlight driving circuit of the invention comprises: a backlight negative terminal VLED -, a driving IC, a bipolar junction transistor BJT (Bipolar Junction Transistor), a field effect transistor MOS (a MOS transistor), a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2; a control output end of the driving IC is connected to a source (S pole) of the MOS transistor; a gate (G pole) of the MOS transistor is connected to a turn-off reference voltage Specifically, the 12V power supply has a drain (D pole) connected to the base (B pole) of the BJT; the emitter (E pole) of the BJT is connected to the feedback input end of the driving IC, and is connected in parallel The first resistor R1 and the second resistor R2 are grounded; the collector (C pole) of the BJT is connected to the backlight negative terminal VLED-.
  • BJT Bipolar Junction Transistor
  • MOS field effect transistor MOS
  • the bipolar junction transistor BJT transistor is a PNP transistor
  • the MOS transistor is an N-channel MOS transistor.
  • the invention places the isolation MOS tube on the B pole of the BJT bipolar junction transistor, and does not affect the feedback voltage V2 to conduct to the driving IC during normal operation, but in the dimming process, the backlight module BLU closes the P interface.
  • the voltage of the negative terminal VLED- of the backlight will be relatively high.
  • the PN transistor is turned on to the MOS transistor through the PNP tube to turn off the MOS transistor, which prevents the high voltage of the VLED- terminal from puncturing the driving IC.
  • the present invention also provides a liquid crystal television set, and the structure of the LED backlight driving circuit is the same as that of the LED backlight driving circuit described above, and details are not described herein again. It should be noted that the present invention describes an LED backlight driving circuit and a product form of a liquid crystal television. Other products satisfying the structure of the present invention, even if the material, device name, appearance, device placement order, etc., do not affect the product. The factors of the characteristics are different and still fall within the scope of protection of the present invention.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Led Devices (AREA)

Abstract

The present invention provides an LED backlight driving circuit and a liquid crystal television set. The LED backlight driving circuit comprises a backlight source negative end, a driving IC, a bipolar junction transistor (BJT), a field effect transistor MOS, and a resistor. A control output end of the driving IC is connected to the source of the field effect transistor MOS. The gate of the field effect transistor MOS is connected to a switch-off reference voltage, and the drain of the field effect transistor MOS is connected to the base of the bipolar junction transistor (BJT). The emitter of the BJT is connected to a feedback input end of the driving IC, and is grounded by means of the resistor. The collector of the BJT is connected to the backlight source negative end. By implementing the present invention, the loss at a plate end can be reduced, and the efficiency can be improved.

Description

一种 LED背光驱动电路及液晶电视机 本申请要求于 2013年 12月 20日提交中国专利局、申请号为 201320846221.1 LED backlight driving circuit and liquid crystal television The application is submitted to the Chinese Patent Office on December 20, 2013, and the application number is 201320846221.1

、 发明名称为 "一种 LED背光驱动电路及液晶电视机" 的中国专利申请的优先 权， 上述专利的全部内容通过引用结合在本申请中。 The invention is entitled to the priority of a Chinese patent application entitled "An LED Backlight Driving Circuit and a Liquid Crystal Television", the entire contents of which are incorporated herein by reference.

技术领域 Technical field

本发明涉及电子技术领域，尤其涉及一种 LED背光驱动电路及液晶电视机。 背景技术  The present invention relates to the field of electronic technologies, and in particular, to an LED backlight driving circuit and a liquid crystal television. Background technique

在现在的 LCD 背光驱动中， LED 驱动集成电路 ( LED Driver integrated circuit )一般都需要侦测 Light Bar负端的电压， 但是背光在 PWM ( Pulse Width Modulation, 脉沖宽带调制）调光时或者 3D时， 背光源 Light Bar负端的电压一 般都比较大， 一般都在 30~50V, 如果输出电压很高， 那么 Light Bar的负端的电 压甚至可能达到七八十伏， 但是一般的 LED Driver IC的侦测 Pin的耐压值一般 都为 30V~40V, 所以一般都是在 Light Bar 负端增加一颗隔离场效应晶体管 MOS, 使其在 Light Bar负端电压大时， 关闭 MOS, 防止损坏 IC。  In the current LCD backlight driver, the LED driver integrated circuit generally needs to detect the voltage at the negative end of the Light Bar, but the backlight is dimmed during PWM (Pulse Width Modulation) dimming or 3D. The voltage at the negative end of the source Light Bar is generally large, generally 30~50V. If the output voltage is high, the voltage at the negative end of the Light Bar may even reach 70 to 80 volts, but the general LED Driver IC detects the Pin. The withstand voltage is generally 30V~40V, so it is common to add an isolated FET MOS at the negative end of the Light Bar to turn off the MOS when the negative voltage of the Light Bar is large, to prevent damage to the IC.

现有技术存在如下缺陷：  The prior art has the following drawbacks:

现有技术中 Light Bar的电流都要流过金属 (metal)—氧化物 (oxid)—半导体 (semiconductor)场效应晶体管 MOS, 这时就要选择一颗大封装的 MOS, 防止 MOS过热， 同时也会降低效率， 并且 MOS上的损耗增加。 发明内容  In the prior art, the current of the Light Bar flows through the metal-oxide-semiconductor field-effect transistor MOS. In this case, a large package MOS is selected to prevent the MOS from overheating. This will reduce efficiency and increase the loss on the MOS. Summary of the invention

为解决现有技术的 LED背光驱动电路中存在的 MOS管发热导致效率降低， 损耗增加的技术问题， 本发明提供一种 LED背光驱动电路及液晶电视机， 所述 LED背光驱动电路包括： 背光源负端、 驱动 IC, 双极结型晶体管 BJT, 场效应 晶体管 MOS, 电阻； 所述驱动 IC的控制输出端与所述场效应晶体管 MOS的源 极连接； 所述场效应晶体管 MOS的栅极连接关断参考电压， 其漏极与所述双极 结型晶体管 BJT的基极连接；所述 BJT的发射极与所述驱动 IC的反馈输入端连 接， 且经所述电阻接地； 所述 BJT的集电极与背光源负端连接。 The invention provides an LED backlight driving circuit and a liquid crystal television set, wherein the LED backlight driving circuit comprises: a backlight source, in order to solve the technical problem that the efficiency of the MOS tube in the prior art LED backlight driving circuit is reduced and the loss is increased. a negative terminal, a driving IC, a bipolar junction transistor BJT, a field effect transistor MOS, a resistor; a control output of the driving IC is connected to a source of the field effect transistor MOS; and a gate connection of the field effect transistor MOS Turning off the reference voltage, the drain of which is connected to the base of the bipolar junction transistor BJT; the emitter of the BJT is connected to the feedback input of the driver IC Connected to and grounded via the resistor; the collector of the BJT is connected to the negative terminal of the backlight.

其中， 所述双极结型晶体管 BJT管为 PNP型晶体管。  Wherein, the bipolar junction transistor BJT transistor is a PNP transistor.

其中， 所述场效应晶体管 MOS为 N沟道 MOS管。  The field effect transistor MOS is an N-channel MOS transistor.

其中， 所述关断参考电压为 12V。  The turn-off reference voltage is 12V.

其中， 所述电阻为并联的第一电阻和第二电阻。  Wherein, the resistor is a first resistor and a second resistor connected in parallel.

本发明还提供一种液晶电视机， 包括： 背光源负端、 驱动 IC, 双极结型晶 体管 BJT, 场效应晶体管 MOS, 电阻； 所述驱动 IC的控制输出端与所述场效应 晶体管 MOS的源极连接； 所述场效应晶体管 MOS的栅极连接关断参考电压， 其漏极与所述双极结型晶体管 BJT的基极连接； 所述 BJT的发射极与所述驱动 IC的反馈输入端连接， 且经所述电阻接地； 所述 BJT的集电极与背光源负端连 接。  The present invention also provides a liquid crystal television set comprising: a backlight negative terminal, a driving IC, a bipolar junction transistor BJT, a field effect transistor MOS, a resistor; a control output terminal of the driving IC and the field effect transistor MOS a source connection; a gate of the field effect transistor MOS is connected to turn off a reference voltage, a drain thereof is connected to a base of the bipolar junction transistor BJT; and a feedback input of the emitter of the BJT and the driving IC The terminal is connected and grounded via the resistor; the collector of the BJT is connected to the negative terminal of the backlight.

其中， 所述双极结型晶体管 BJT管为 PNP型晶体管。  Wherein, the bipolar junction transistor BJT transistor is a PNP transistor.

其中， 所述场效应晶体管 MOS为 N沟道 MOS管。  The field effect transistor MOS is an N-channel MOS transistor.

其中， 所述关断参考电压为 12V。  The turn-off reference voltage is 12V.

其中， 所述电阻为并联的第一电阻和第二电阻。  Wherein, the resistor is a first resistor and a second resistor connected in parallel.

实施本发明， 在 BJT的 B极与驱动 IC之间设置一隔离 MOS, 正常工作时 不会影响反馈电压导通至 IC, 且在调光过程中， 背光模组 BLU关闭阶段， 背光 源负端 VLED-的电压会比较高， 这时通过双极结型晶体管 BJT管中 PN节导通 至 MOS管， 使 MOS管关闭， 即可防止 VLED-端的高压将驱动 IC击穿。 同时， 由于 MOS设置在 BJT的基极（ B极）， 流过此极的电流极小， 因此可以不用考 虑其在 MOS上的损耗， 即使选用一颗较小封装的 MOS, 也可以降低在板端的 损耗， 提高效率。 附图说明 例或现有技术描述中所需要使用的附图作筒单地介绍， 显而易见地， 下面描述 中的附图仅仅是本发明的一些实施例， 对于本领域普通技术人员来讲， 在不付 出创造性劳动性的前提下， 还可以根据这些附图获得其他的附图。  By implementing the invention, an isolation MOS is disposed between the B pole of the BJT and the driving IC, and the feedback voltage is not conducted to the IC during normal operation, and during the dimming process, the backlight module BLU is turned off, and the backlight is negative. The voltage of VLED- will be relatively high. At this time, the PN transistor in the BJT tube of the bipolar junction transistor is turned on to the MOS transistor to turn off the MOS transistor, thereby preventing the high voltage of the VLED- terminal from breaking down the driving IC. At the same time, since the MOS is set at the base (B pole) of the BJT, the current flowing through this pole is extremely small, so that the loss on the MOS can be ignored, even if a smaller package MOS is used, the board can be lowered. End loss, improve efficiency. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in the claims Other drawings may also be obtained from these drawings without the inventive labor.

图 1是本发明 LED背光驱动电路的电路示意图。 具体实施方式 1 is a circuit diagram of an LED backlight driving circuit of the present invention. detailed description

为解决上述技术问题， 本发明提供一种 LED背光驱动电路， 包括背光源负 端、 驱动 IC, 双极结型晶体管 BJT, 场效应晶体管 MOS, 电阻； 所述驱动 IC 的控制输出端与所述场效应晶体管 MOS的源极连接； 所述场效应晶体管 MOS 的栅极连接关断参考电压， 其漏极与所述双极结型晶体管 BJT的基极连接； 所 述 BJT的发射极与所述驱动 IC的反馈输入端连接， 且经所述电阻接地； 所述 BJT的集电极与背光源负端连接。  In order to solve the above technical problem, the present invention provides an LED backlight driving circuit including a backlight negative terminal, a driving IC, a bipolar junction transistor BJT, a field effect transistor MOS, a resistor; a control output terminal of the driving IC and the a source of the field effect transistor MOS is connected; a gate of the field effect transistor MOS is connected to turn off a reference voltage, a drain thereof is connected to a base of the bipolar junction transistor BJT; and an emitter of the BJT is The feedback input of the driver IC is connected and grounded via the resistor; the collector of the BJT is connected to the negative terminal of the backlight.

在具体实现中， 所述关断参考电压为 12V, 此处仅为举例。 另外， 与 BJT 的发射极连接的电阻具体为第一电阻 R1和第二电阻 R2。 具体的， 参见图 1 , 其 是本发明 LED背光驱动电路的具体电路示意图， 下面结合图 1及具体实施例详 细说明本发明的技术方案。  In a specific implementation, the turn-off reference voltage is 12V, which is merely an example. In addition, the resistor connected to the emitter of the BJT is specifically a first resistor R1 and a second resistor R2. Specifically, referring to FIG. 1 , which is a specific circuit diagram of the LED backlight driving circuit of the present invention, the technical solution of the present invention will be described in detail below with reference to FIG. 1 and specific embodiments.

本发明的 LED背光驱动电路包括： 背光源负端 VLED -、 驱动 IC, 双极结 型晶体管 BJT ( Bipolar Junction Transistor ), 场效应晶体管 MOS (筒称 MOS 管）， 第一电容 C1 , 第二电容 C2, 第一电阻 R1 , 第二电阻 R2; 所述驱动 IC的 控制输出端与所述 MOS管的源极（ S极）连接； 所述 MOS管的栅极（ G极） 连接关断参考电压， 具体为 12V电源， 其漏极（D极）与所述 BJT的基极 ( B 极 )连接； 所述 BJT的发射极（ E极）与所述驱动 IC的反馈输入端连接， 且经 并联的第一电阻 R1和第二电阻 R2接地； 所述 BJT的集电极（C极）与所述背 光源负端 VLED-连接。  The LED backlight driving circuit of the invention comprises: a backlight negative terminal VLED -, a driving IC, a bipolar junction transistor BJT (Bipolar Junction Transistor), a field effect transistor MOS (a MOS transistor), a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2; a control output end of the driving IC is connected to a source (S pole) of the MOS transistor; a gate (G pole) of the MOS transistor is connected to a turn-off reference voltage Specifically, the 12V power supply has a drain (D pole) connected to the base (B pole) of the BJT; the emitter (E pole) of the BJT is connected to the feedback input end of the driving IC, and is connected in parallel The first resistor R1 and the second resistor R2 are grounded; the collector (C pole) of the BJT is connected to the backlight negative terminal VLED-.

在具体实现中， 所述双极结型晶体管 BJT管为 PNP型晶体管， 所述 MOS 管为 N沟道 MOS管。  In a specific implementation, the bipolar junction transistor BJT transistor is a PNP transistor, and the MOS transistor is an N-channel MOS transistor.

本发明将隔离 MOS管放置在 BJT双极结型晶体管的 B极， 正常工作时 不会影响到反馈电压 V2导通至驱动 IC, 但是在调光过程中， 背光模组 BLU关 闭 P介段， 背光源负端 VLED-的电压会比较高， 这时候通过 PNP管中 PN节导通 至 MOS管， 使 MOS管关闭， 就可防止 VLED-端的高压将驱动 IC击穿。 同时， 由于 MOS管是使用在 BJT的 B极， 流过此极的电流极小， 所以可以不用考虑 其在 MOS上的损耗， 可以选用一颗较小封装的 MOS, 也可以降低在板端的损 耗， 提高效率。  The invention places the isolation MOS tube on the B pole of the BJT bipolar junction transistor, and does not affect the feedback voltage V2 to conduct to the driving IC during normal operation, but in the dimming process, the backlight module BLU closes the P interface. The voltage of the negative terminal VLED- of the backlight will be relatively high. At this time, the PN transistor is turned on to the MOS transistor through the PNP tube to turn off the MOS transistor, which prevents the high voltage of the VLED- terminal from puncturing the driving IC. At the same time, since the MOS transistor is used in the B pole of the BJT, the current flowing through this pole is extremely small, so that the loss on the MOS can be ignored, and a smaller package MOS can be selected, and the loss at the board end can also be reduced. , Improve efficiency.

本发明还提供一种液晶电视机，其 LED背光驱动电路的结构与上述的 LED 背光驱动电路的结构相同， 在此不再赘述。 值得注意的是， 本发明描述的是 LED背光驱动电路以及液晶电视机的一种 产品形式， 其它满足本发明所述结构的产品， 即使材质、 器件名称、 外观、 器 件摆放顺序等不影响产品特性的因素不相同， 仍然属于本发明保护的范围。 The present invention also provides a liquid crystal television set, and the structure of the LED backlight driving circuit is the same as that of the LED backlight driving circuit described above, and details are not described herein again. It should be noted that the present invention describes an LED backlight driving circuit and a product form of a liquid crystal television. Other products satisfying the structure of the present invention, even if the material, device name, appearance, device placement order, etc., do not affect the product. The factors of the characteristics are different and still fall within the scope of protection of the present invention.

以上内容是结合具体的优选实施方式对本发明所作的进一步详细说明， 不 能认定本发明的具体实施只局限于这些说明。 对于本发明所属技术领域的普通 技术人员来说， 在不脱离本发明构思的前提下， 还可以做出若干筒单推演或替 换， 都应当视为属于本发明的保护范围。  The above is a further detailed description of the present invention in connection with the specific preferred embodiments. It is not intended that the specific embodiments of the invention are limited to the description. It will be apparent to those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention.

Claims

权利 要 求 Rights request 1、 一种 LED背光驱动电路， 其中， 包括： 背光源负端、 驱动 IC, 双极 结型晶体管 BJT, 场效应晶体管 MOS, 电阻； 所述驱动 IC的控制输出端与 所述场效应晶体管 MOS的源极连接；所述场效应晶体管 MOS的栅极连接关 断参考电压，其漏极与所述双极结型晶体管 BJT的基极连接； 所述 BJT的发 射极与所述驱动 IC的反馈输入端连接， 且经所述电阻接地； 所述 BJT的集 电极与背光源负端连接。 1. An LED backlight drive circuit, which includes: a backlight negative terminal, a drive IC, a bipolar junction transistor BJT, a field effect transistor MOS, and a resistor; the control output end of the drive IC and the field effect transistor MOS The source electrode is connected; the gate electrode of the field effect transistor MOS is connected to the turn-off reference voltage, and its drain electrode is connected to the base electrode of the bipolar junction transistor BJT; the emitter electrode of the BJT is connected to the feedback of the driver IC The input end is connected and grounded through the resistor; the collector of the BJT is connected to the negative end of the backlight. 2、 如权利要求 1所述的 LED背光驱动电路， 其中， 所述双极结型晶体 管 BJT管为 PNP型晶体管。 2. The LED backlight drive circuit as claimed in claim 1, wherein the bipolar junction transistor (BJT) is a PNP transistor. 3、 如权利要求 2所述的 LED背光驱动电路， 其中， 所述场效应晶体管 MOS为 N沟道 MOS管。 3. The LED backlight drive circuit of claim 2, wherein the field effect transistor MOS is an N-channel MOS transistor. 4、 如权利要求 3所述的 LED背光驱动电路， 其中， 所述关断参考电压 为 12V。 4. The LED backlight drive circuit as claimed in claim 3, wherein the turn-off reference voltage is 12V. 5、 如权利要求 4所述的 LED背光驱动电路， 其中， 所述电阻为并联的 第一电阻和第二电阻。 5. The LED backlight driving circuit of claim 4, wherein the resistor is a first resistor and a second resistor connected in parallel. 6、 一种 LED背光驱动电路， 其中， 包括： 背光源负端、 驱动 IC, 双极 结型晶体管 BJT, 场效应晶体管 MOS, 电阻； 所述驱动 IC的控制输出端与 所述场效应晶体管 MOS的源极连接；所述场效应晶体管 MOS的栅极连接关 断参考电压，其漏极与所述双极结型晶体管 BJT的基极连接； 所述 BJT的发 射极与所述驱动 IC的反馈输入端连接， 且经所述电阻接地； 所述 BJT的集 电极与背光源负端连接； 6. An LED backlight drive circuit, which includes: a backlight negative terminal, a drive IC, a bipolar junction transistor BJT, a field effect transistor MOS, and a resistor; the control output end of the drive IC and the field effect transistor MOS The source electrode is connected; the gate electrode of the field effect transistor MOS is connected to the turn-off reference voltage, and its drain electrode is connected to the base electrode of the bipolar junction transistor BJT; the emitter electrode of the BJT is connected to the feedback of the driver IC The input end is connected and grounded through the resistor; the collector of the BJT is connected to the negative end of the backlight; 其中， 所述双极结型晶体管 BJT管为 PNP型晶体管。 Wherein, the bipolar junction transistor BJT transistor is a PNP transistor. 其中， 所述场效应晶体管 MOS为 N沟道 MOS管。 Wherein, the field effect transistor MOS is an N-channel MOS transistor. 7、 一种液晶电视机， 其中， 包括： 背光源负端、 驱动 IC, 双极结型晶 体管 BJT, 场效应晶体管 MOS, 电阻； 所述驱动 IC的控制输出端与所述场 效应晶体管 MOS的源极连接；所述场效应晶体管 MOS的栅极连接关断参考 电压，其漏极与所述双极结型晶体管 BJT的基极连接； 所述 BJT的发射极与 所述驱动 IC的反馈输入端连接， 且经所述电阻接地； 所述 BJT的集电极与 背光源负端连接。 7. An LCD TV, including: negative terminal of backlight, driver IC, bipolar crystal BJT, field effect transistor MOS, resistor; the control output terminal of the driver IC is connected to the source of the field effect transistor MOS; the gate of the field effect transistor MOS is connected to the shutdown reference voltage, and its drain is connected to the source of the field effect transistor MOS. The base of the bipolar junction transistor BJT is connected; the emitter of the BJT is connected to the feedback input terminal of the driver IC and is grounded through the resistor; and the collector of the BJT is connected to the negative terminal of the backlight source. 8、 如权利要求 7所述的液晶电视机， 其中， 所述双极结型晶体管 BJT 管为 PNP型晶体管。 8. The liquid crystal television set according to claim 7, wherein the bipolar junction transistor (BJT) is a PNP transistor. 9、 如权利要求 8所述的液晶电视机， 其中， 所述场效应晶体管 MOS为 N沟道 MOS管。 9. The liquid crystal television set according to claim 8, wherein the field effect transistor MOS is an N-channel MOS transistor. 10、如权利要求 9所述的液晶电视机， 其中，所述关断参考电压为 12V。 10. The liquid crystal television set of claim 9, wherein the turn-off reference voltage is 12V. 11、 如权利要求 10所述的液晶电视机， 其中， 所述电阻为并联的第一 电阻和第二电阻。 11. The liquid crystal television set according to claim 10, wherein the resistor is a first resistor and a second resistor connected in parallel.
PCT/CN2014/070523 2013-12-20 2014-01-13 Led backlight driving circuit and liquid crystal television set Ceased WO2015089924A1 (en)

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