WO2014075326A1 - 实现led灯条电流倍增的方法及其对应的驱动电路 - Google Patents

实现led灯条电流倍增的方法及其对应的驱动电路 Download PDF

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Publication number
WO2014075326A1
WO2014075326A1 PCT/CN2012/084996 CN2012084996W WO2014075326A1 WO 2014075326 A1 WO2014075326 A1 WO 2014075326A1 CN 2012084996 W CN2012084996 W CN 2012084996W WO 2014075326 A1 WO2014075326 A1 WO 2014075326A1
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Prior art keywords
constant current
pin
led light
electrically connected
source
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PCT/CN2012/084996
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English (en)
French (fr)
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张华�
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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 US13/807,717 priority Critical patent/US9538593B2/en
Publication of WO2014075326A1 publication Critical patent/WO2014075326A1/zh

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    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/40Details of LED load circuits
    • H05B45/44Details of LED load circuits with an active control inside an LED matrix

Definitions

  • the present invention relates to the field of liquid crystal displays, and in particular, to a method for multiplying current of LED strips of a backlight in a backlight module and a corresponding driving circuit thereof. Background technique
  • LED Light Emitting Diode
  • the color emitted by each LED depends on the energy of the photon, and the energy of the photon is also produced. Material varies. The same material has a very close illuminating wavelength, so each LED is pure in color. The most common LEDs of general brightness are red and grass green. The LED has a small grain size and a wide variety of colors. The arrangement is very flexible in use, which is superior to the general light source. In addition, the LED has higher light efficiency and higher efficiency than other light sources. Reliability, the method of power supply is also relatively simple. Therefore, LEDs are particularly suitable for use as display light sources, such as backlights in liquid crystal displays.
  • the forward voltage drop of the LED does not change much with the on current, generally about 3.5V, and its illuminance increases as the current it passes increases.
  • the current is large, the light output And the illumination is also large. Therefore, the LED requires a series power supply, and is a constant current power supply.
  • the current flowing through the tube is constant to maintain a stable light output.
  • the output is required to have a constant current characteristic, and the series LED is required. Power supply, therefore, the use of LED constant current drive chip to drive LED strips came into being.
  • the LED constant current driving chip 200 is powered on, a constant voltage is generated internally, and this voltage is determined together with the external resistance value R100 of the constant current driving chip 200 current setting pin pin.
  • the current value flowing in the LED light bar 100 is subject to the semiconductor process and the heat generation problem.
  • the maximum current of a single channel of the LED constant current driving chip 200 of each manufacturer can be set to 300 mA.
  • the size of liquid crystal display panels is getting larger and larger, and the backlight brightness of liquid crystal display panels required is getting higher and higher.
  • the existing LED backlight driving circuits are all using LED constant current driving chips.
  • the single constant current driving module drives an LED light bar, and the current through the LED light bar cannot reach 300 mA or more.
  • the LED light bar is unable to provide a higher brightness light source due to the limitation of the driving current, and is difficult to satisfy the large size liquid crystal display. Demand.
  • Summary of the invention is to provide a method for realizing current multiplication of LED strips, which can increase the current flowing through the LED strips, improve the brightness of the LED strips, and produce a backlight with higher brightness to meet the requirements of large-size liquid crystal displays.
  • Another object of the present invention is to provide an LED light bar driving circuit, which has a simple circuit structure, improves the current flowing through the LED light bar, thereby improving the brightness of the LED light bar, and generating a higher brightness backlight to meet the large size.
  • the present invention provides a method for realizing current multiplication of LED strips, comprising the following steps:
  • Step 1 Providing a constant current driving chip and a plurality of resistors, the constant current driving chip having a plurality of constant current driving modules, wherein each constant current driving module includes first to third pins;
  • Step 2 providing an LED light bar, a power source and a PWM control source, wherein the LED light bar has a positive pole and a negative pole;
  • Step 3 Connect one end of a resistor to the third pin of a constant current driving module, and connect the other end to the ground. Connect the first pin of the constant current driving module to the negative pole of the LED strip.
  • the second pin of the stream drive module is connected to the PWM control source, and connects the anode of the LED strip to the power source;
  • Step 4 repeating step 3 several times as needed, so that a plurality of constant current driving modules are electrically connected to the LED light bar, the plurality of resistors, the power source, and the PWM control source;
  • Step 5 Turn on the power and PWM control source, and use multiple constant current driving modules to simultaneously drive the same LED strip to emit light.
  • the constant current driving chip has a number of constant current driving modules greater than two, and the number of the resistors corresponds to the number of constant current driving modules of the constant current driving chip.
  • Each of the constant current driving modules includes: a field effect transistor and a voltage comparator electrically connected to the field effect transistor, the FET comprising: a gate, a source, and a drain, the drain The pole is electrically connected to the negative pole of the LED strip, the gate is electrically connected to the voltage comparator, and the source is electrically connected to the resistor on the third pin of the constant current driving module.
  • the voltage comparator includes: a positive pin, a negative pin, and an output pin, wherein the positive pin is electrically connected to a PWM control source, and the negative pin is electrically connected to a source of the FET, The output pin is electrically connected to the gate of the FET.
  • the PWM control source outputs a high level and a low level, the high level being greater than a voltage on a source when the FET is normally turned on, and the low level is less than a source when the FET is normally turned on
  • the voltage on the voltage comparator is greater than the threshold voltage of the FET.
  • the invention also provides an LED light bar driving circuit, comprising: a constant current driving chip, a plurality of resistors, an LED light bar, a power source and a PWM control source, the constant current driving chip having a plurality of constant currents a driving module, each of the constant current driving modules includes first to third pins, the LED light bar has a positive electrode and a negative electrode, and a positive pole of the LED light bar is electrically connected to a power source, and each of the resistors One end is connected to the third pin of a constant current driving module, and the other end is connected to the ground line, and the first pin of the constant current driving module connected with the resistor is connected to the negative pole of the LED strip, the second lead The feet are connected to the PWM control source.
  • the number of the resistors is not less than two, and the constant current driving chip has not less than two constant current driving modules.
  • Each of the constant current driving modules includes: a field effect transistor and a voltage comparator electrically connected to the field effect transistor, the FET comprising: a gate, a source, and a drain, the drain The pole is electrically connected to the negative pole of the LED strip, the gate is electrically connected to the voltage comparator, and the source is electrically connected to the resistor on the third pin of the constant current driving module.
  • the voltage comparator includes: a positive pin, a negative pin, and an output pin, wherein the positive pin is electrically connected to a PWM control source, and the negative pin is electrically connected to a source of the FET, The output pin is electrically connected to the gate of the FET.
  • the PWM control source outputs a high level and a low level, the high level being greater than a voltage on a source when the FET is normally turned on, and the low level is less than a source when the FET is normally turned on
  • the voltage on the voltage comparator is greater than the threshold voltage of the FET.
  • the invention also provides a method for realizing current multiplication of LED strips, comprising the following steps: Step 1. Providing a constant current driving chip and a plurality of resistors, the constant current driving chip having a plurality of constant current driving modules, each of The constant current driving module includes first to third pins;
  • Step 2 providing an LED light bar, a power source and a PWM control source, wherein the LED light bar has a positive pole and a negative pole;
  • Step 3 Connect one end of a resistor to the third pin of a constant current driving module, and connect the other end to the ground. Connect the first pin of the constant current driving module to the negative pole of the LED strip.
  • the second pin of the stream drive module is connected to the PWM control source, and connects the anode of the LED strip to the power source;
  • Step 4 repeating step 3 several times as needed, so that a plurality of constant current driving modules are electrically connected to the LED light bar, the plurality of resistors, the power source, and the PWM control source;
  • Step 5 Turn on the power supply and the PWM control source, and use a plurality of constant current driving modules to simultaneously drive the same LED strip to emit light;
  • the constant current driving chip has a number of constant current driving modules greater than two, and the number of the resistors corresponds to the number of constant current driving modules of the constant current driving chip;
  • Each of the constant current driving modules includes: a field effect transistor and a voltage comparator electrically connected to the FET, the FET comprising: a gate, a source, and a drain, Description The drain is electrically connected to the negative electrode of the LED strip, the gate is electrically connected to the voltage comparator, and the source is electrically connected to the resistor on the third pin of the constant current driving module;
  • the voltage comparator includes: a positive pin, a negative pin, and an output pin, wherein the positive pin is electrically connected to a PWM control source, and the negative pin is electrically connected to a source of the FET The output pin is electrically connected to a gate of the FET;
  • the PWM control source outputs a high level and a low level, and the high level is greater than a voltage on the source when the FET is normally turned on, and the low level is less than when the FET is normally turned on.
  • the voltage on the source, the voltage output by the voltage comparator is greater than the threshold voltage of the FET.
  • the method for realizing LED current double multiplication of the present invention uses two or more constant current driving modules to simultaneously drive the same LED light bar, which can increase the current flowing through the LED light bar and improve the LED light bar.
  • the LED light bar driving circuit of the invention has a simple structure, improves the current flowing through the LED strips, thereby improving the brightness of the LED strips and generating higher brightness
  • the backlight meets the needs of large-size LCD monitors.
  • FIG. 3 is a circuit diagram of a plurality of constant current driving modules simultaneously driving the same LED strip in the present invention. detailed description
  • the present invention provides a method for realizing current multiplication of LED strips, including the following steps:
  • Step 1 A constant current driving chip 30 and a plurality of resistors R are provided.
  • the constant current driving chip 30 has a plurality of constant current driving modules 32, and each of the constant current driving modules 32 includes first to third leads. Fees 1 to 3;
  • the PWM control source 40 outputs a high level and a low level, the high level being greater than a voltage on the source s when the FET Q is normally turned on, the low level being less than the normal conduction of the FET Q
  • the voltage on the source s is ensured that the voltage comparator D outputs a high-level drive FET Q when the positive pin of the voltage comparator D is input high, and is positive at the voltage comparator D.
  • the voltage comparator can output a low level, and the low level cannot turn on the FET Q; the voltage output by the voltage comparator D is greater than the threshold of the FET Q.
  • the voltage ensures that the voltage output from the voltage comparator can normally drive the FET Q, causing the FET Q to switch between the on and off states.
  • Step 3 Connect a resistor R-terminal to the third pin of a constant current driving module 32, and connect the other end to the ground, and connect the first pin 1 of the constant current driving module 32 to the LED strip 10
  • the negative pole, the second pin of the constant current driving module 32 is connected to the PWM control source 40, and the anode of the LED light bar 10 is connected to the power source 20;
  • the voltage comparator D includes: a positive pin, a negative pin and an output pin, the positive pin is electrically connected to the PWM control source 40, and the negative pin is electrically connected to the source s of the FET Q.
  • the output pin is electrically connected to the gate g of the FET Q, and the voltage comparator D outputs a stable voltage to drive the FET.
  • the plurality of constant current driving modules 32 can simultaneously drive the same LED light bar 10, and the plurality of constant current driving modules 32 divide the current flowing through the LED light bar 10, thereby causing the LED light bar to flow.
  • the magnitude of the current of 10 is not limited by the maximum current of a single constant current drive module 32.
  • Step 5 Turn on the power source 20 and the PWM control source 40, and simultaneously drive the same LED strip 10 to emit light by using a plurality of constant current driving modules 32.
  • the invention uses two or more constant current driving modules 32 to simultaneously drive the same LED light bar 10, which can increase the current flowing through the LED light bar 10, is not limited by the maximum current of the single constant current driving module 32, and improves the LED.
  • the brightness of the light bar 10 produces a higher brightness backlight that meets the needs of large size liquid crystal displays.
  • the present invention further provides an LED light bar driving circuit, comprising: a constant current driving chip 30, a plurality of resistors R, an LED light bar 10, a power source 20, and a PWM control source 40.
  • the constant current driving chip 30 There are a plurality of constant current driving modules 32, each of the constant current driving modules 32 includes first to third pins 1 to 3, the LED light bar 10 has a positive electrode and a negative electrode, and the LED light bar 10
  • the positive pole is electrically connected to the power source 20, and the R- terminal of each resistor is connected to the third pin 3 of a constant current driving module 32, and the other end is connected to the ground, and the constant current driving module connected with the resistor R is connected.
  • the first pin 1 of 32 is connected to the negative pole of the LED strip 10, and the second pin 2 is connected to the PWM control source 40.
  • Each of the constant current driving modules 32 includes: a field effect transistor Q and a voltage comparator D electrically connected to the field effect transistor Q.
  • the FET Q includes: a gate g, a source s, and a drain d, the drain d is electrically connected to the cathode of the LED strip 10, the gate g is electrically connected to the voltage comparator D, and the source s and the constant current driving module 32 are The resistor R on the three pins 3 is electrically connected.
  • the conduction or disconnection of the LED strip 10 is controlled by the on or off of the FET Q, which is safe and reliable, and has a long switch life.
  • the voltage comparator D includes: a positive pin, a negative pin and an output pin, wherein the positive pin is electrically connected to the PWM control source 40, and the negative pin and the source of the FET Q s electrical connection, the output pin and the FET The gate g of Q is electrically connected, and the voltage comparator D outputs a stable voltage to drive the field effect transistor Q.
  • the PWM control source 40 outputs a high level and a low level, the high level being greater than a voltage on the source s when the FET Q is normally turned on, the low level being less than the normal conduction of the FET Q
  • the voltage on the source S of the pass ensures that when the positive pin is input high, the voltage comparator D can output a high level to drive the FET Q, and when the positive pin is input low, the The voltage comparator outputs a low level, and the low level cannot turn on the FET Q; the voltage outputted by the voltage comparator D is greater than the threshold voltage of the FET Q, and the voltage output by the voltage comparator is ensured.
  • the field effect transistor Q can be normally driven such that the field effect transistor Q is switched between an on state and an off state.
  • the LED light bar driving circuit working process of the invention turns on the PWM control source 40 and the power source 10, the PWM control source 10 outputs a high level according to actual needs, and the voltage comparator D outputs a high level driving field effect transistor Q
  • the FET Q is turned from the off state to the on state, and the LED strip 10 forms a loop with the plurality of constant current driving modules 32 to drive the LED strip 10 to emit light, wherein the plurality of constant current driving Module 32 splits the current flowing through the LED strip 10.
  • the present invention provides a method for realizing current multiplication of LED strips by using two or more constant current driving modules to simultaneously drive the same LED strip, which can increase the current flowing through the LED strips and improve the LED lights.
  • the brightness of the strips produces a higher brightness backlight, which satisfies the requirements of large-size liquid crystal displays.
  • the LED strip driving circuit of the invention has a simple structure, improves the current flowing through the LED strips, and thereby improves the brightness of the LED strips, thereby generating more High-brightness backlight for large-size LCD displays.

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Abstract

本发明提供一种实现LED灯条电流倍增的方法及其对应的驱动电路,该方法包括以下步骤:步骤1、提供一恒流驱动芯片及数个电阻,该恒流驱动芯片具有数个恒流驱动模块,该每一恒流驱动模块包括第一至第三引脚;步骤2、提供一LED灯条、电源及PWM控制源;步骤3、将一电阻一端连接于一恒流驱动模块的第三引脚,另一端连接于地线,将该恒流驱动模块的第一引脚连接于该LED灯条的负极,将该流驱动模块的第二引脚连接于PWM控制源,并将LED灯条的正极连接于电源;步骤4、根据需要重复步骤3数次,使得数个恒流驱动模块与该LED灯条电性连接;步骤5、接通电源及PWM控制源,利用多个恒流驱动模块同时驱动同一LED灯条进行发光。

Description

实现 LED灯条电流倍增的方法及其对应的驱动电路 技术领域
本发明涉及液晶显示器领域, 尤其涉及一种背光模组中背光源的 LED 灯条电流倍增的方法及其对应的驱动电路。 背景技术
发光二极管 (LED, Light Emitting Diode )是一种固态光源, 利用半 导体中的电子和空穴相结合而发出光子, 每种 LED 所发出的颜色取决于 光子的能量, 而光子的能量又因其制造材料而异。 同一种材料的发光波长 很接近, 因此每颗 LED的颜色都很纯正, 最常见的一般亮度的 LED多是 红色和草绿色。 LED 晶粒尺寸小, 颜色种类多, 使用时排列方式又有很大 的灵活, 这是它比一般光源优越的地方; 另外, LED与其他光源相比还具 有较高的光效和更高的可靠性, 供电的方法也比较简单。 因而 LED 特别 适合用作显示光源, 如: 液晶显示器中的背光源等。
与一般的半导体 PN结一样, LED的正向导通压降随导通电流的变化 并不大, 一般为 3.5V 左右, 其照度是随着其通过的电流增加而增加的, 电流大, 光输出及照度也大。 所以, LED要求采用串联供电, 而且是恒流 的电源, 流经管子的电流为定值, 以保持稳定的光输出, 作为 LED 的驱 动芯片, 要求其输出具有恒流特性, 对串联的 LED 进行供电, 因此, 采 用 LED恒流驱动芯片驱动 LED灯条则应运而生。
请参阅图 1 , 但在现有技术中, LED 恒流驱动芯片通电后, 内部会产 生一个恒定的电压, 此电压与恒流驱动芯片 200 电流设置引脚 pin上外接 的电阻值 R100共同决定了 LED灯条 100中流过的电流值, 但是受制于半 导体制程以及发热问题, 目前各个厂家的 LED 恒流驱动芯片 200 的单个 通道能设置的最大值电流为 300mA。 但随着科技的发展, 现今液晶显示面 板的尺寸越来越大, 所需要的液晶显示面板的背光亮度也越来越高, 现有 的 LED背光驱动电路, 都是使用 LED恒流驱动芯片中的单个恒流驱动模 块来驱动一 LED灯条, 无法使得通过该 LED灯条的电流达到 300mA以 上, LED灯条因受到驱动电流的限制, 无法提供更高亮度的光源, 难于满 足大尺寸液晶显示器的需求。 发明内容 本发明的目的在于提供一种实现 LED 灯条电流倍增的方法, 可以增 加流过 LED 灯条的电流, 提高 LED 灯条的亮度, 产生更高亮度的背光 源, 满足大尺寸液晶显示器的需求。
本发明的另一目的还在于提供一种 LED 灯条驱动电路, 电路结构简 单, 提高了流过 LED灯条的电流, 进而提高 LED灯条的亮度, 产生更高 亮度的背光源, 满足大尺寸液晶显示器的需求。
为实现上述目的, 本发明提供一种实现 LED 灯条电流倍增的方法, 包括以下步骤:
步骤 1、 提供一恒流驱动芯片及数个电阻, 该恒流驱动芯片具有数个 恒流驱动模块, 所述每一恒流驱动模块包括第一至第三引脚;
步骤 2、 提供一 LED灯条、 电源及 PWM控制源, 所述 LED灯条具 有一正极及一负极;
步骤 3、 将一电阻一端连接于一恒流驱动模块的第三引脚, 另一端连 接于地线, 将该恒流驱动模块的第一引脚连接于该 LED 灯条的负极, 将 该恒流驱动模块的第二引脚连接于 PWM控制源, 并将 LED灯条的正极连 接于电源;
步骤 4、 根据需要重复步骤 3 数次, 使得数个恒流驱动模块分别与该 LED灯条、 该数个电阻、 该电源及该 PWM控制源电性连接;
步骤 5、 接通电源及 PWM控制源, 利用多个恒流驱动模块同时驱动 同一 LED灯条进行发光。
所述恒流驱动芯片具有恒流驱动模块的数量大于两个, 所述电阻的数 量对应所述恒流驱动芯片具有的恒流驱动模块的数量。
所述每一恒流驱动模块包括: 一场效应管及与该场效应管电性连接的 电压比较器, 所述场效应管包括: 一栅极、 一源极及一漏极, 所述漏极与 该 LED 灯条的负极电性连接, 所述栅极与电压比较器电性连接, 所述源 极与该恒流驱动模块的第三引脚上的电阻电性连接。
所述电压比较器包括: 正引脚、 负引脚及输出引脚, 所述正引脚与 PWM控制源电性连接, 所述负引脚与该场效应管的源极电性连接, 所述 输出引脚与该场效应管的栅极电性连接。
所述 PWM控制源输出高电平及低电平, 所述高电平大于该场效应管 正常导通时源极上的电压, 所述低电平小于该场效应管正常导通时源极上 的电压, 所述电压比较器输出的电压大于该场效应管的阔值电压。
本发明还提供一种 LED 灯条驱动电路, 包括: 恒流驱动芯片、 数个 电阻、 一 LED灯条、 电源及 PWM控制源, 该恒流驱动芯片具有数个恒流 驱动模块, 所述每一恒流驱动模块包括第一至第三引脚, 所述 LED 灯条 具有一正极及一负极, 所述 LED 灯条的正极与电源电性连接, 所述每一 电阻一端连接于一恒流驱动模块的第三引脚上, 另一端连接于地线, 所述 接有电阻的恒流驱动模块的第一引脚都连接于该 LED 灯条的负极, 第二 引脚都连接于 PWM控制源。
所述电阻的数量不少于两个, 所述恒流驱动芯片具有恒流驱动模块的 数量不少于两个。
所述每一恒流驱动模块包括: 一场效应管及与该场效应管电性连接的 电压比较器, 所述场效应管包括: 一栅极、 一源极及一漏极, 所述漏极与 该 LED 灯条的负极电性连接, 所述栅极与电压比较器电性连接, 所述源 极与该恒流驱动模块的第三引脚上的电阻电性连接。
所述电压比较器包括: 正引脚、 负引脚及输出引脚, 所述正引脚与 PWM控制源电性连接, 所述负引脚与该场效应管的源极电性连接, 所述 输出引脚与该场效应管的栅极电性连接。
所述 PWM控制源输出高电平及低电平, 所述高电平大于该场效应管 正常导通时源极上的电压, 所述低电平小于该场效应管正常导通时源极上 的电压, 所述电压比较器输出的电压大于该场效应管的阔值电压。
本发明还提供一种实现 LED灯条电流倍增的方法, 包括以下步骤: 步骤 1、 提供一恒流驱动芯片及数个电阻, 该恒流驱动芯片具有数个 恒流驱动模块, 所述每一恒流驱动模块包括第一至第三引脚;
步骤 2、 提供一 LED灯条、 电源及 PWM控制源, 所述 LED灯条具 有一正极及一负极;
步骤 3、 将一电阻一端连接于一恒流驱动模块的第三引脚, 另一端连 接于地线, 将该恒流驱动模块的第一引脚连接于该 LED 灯条的负极, 将 该恒流驱动模块的第二引脚连接于 PWM控制源, 并将 LED灯条的正极连 接于电源;
步骤 4、 根据需要重复步骤 3 数次, 使得数个恒流驱动模块分别与该 LED灯条、 该数个电阻、 该电源及该 PWM控制源电性连接;
步骤 5、 接通电源及 PWM控制源, 利用多个恒流驱动模块同时驱动 同一 LED灯条进行发光;
其中, 所述恒流驱动芯片具有恒流驱动模块的数量大于两个, 所述电 阻的数量对应所述恒流驱动芯片具有的恒流驱动模块的数量;
其中, 所述每一恒流驱动模块包括: 一场效应管及与该场效应管电性 连接的电压比较器, 所述场效应管包括: 一栅极、 一源极及一漏极, 所述 漏极与该 LED 灯条的负极电性连接, 所述栅极与电压比较器电性连接, 所述源极与该恒流驱动模块的第三引脚上的电阻电性连接;
其中, 所述电压比较器包括: 正引脚、 负引脚及输出引脚, 所述正引 脚与 PWM控制源电性连接, 所述负引脚与该场效应管的源极电性连接, 所述输出引脚与该场效应管的栅极电性连接;
其中, 所述 PWM控制源输出高电平及低电平, 所述高电平大于该场 效应管正常导通时源极上的电压, 所述低电平小于该场效应管正常导通时 源极上的电压, 所述电压比较器输出的电压大于该场效应管的阔值电压。
本发明的有益效果: 本发明实现 LED 灯条电流倍增的方法采用两个 或两个以上的恒流驱动模块同时驱动同一 LED 灯条, 可以增加流过 LED 灯条的电流, 提高 LED 灯条的亮度, 产生更高亮度的背光源, 满足大尺 寸液晶显示器的需求; 本发明 LED 灯条驱动电路结构简单, 提高了流过 LED 灯条的电流, 进而提高 LED 灯条的亮度, 产生更高亮度的背光源, 满足大尺寸液晶显示器的需求。
为了能更进一步了解本发明的特征以及技术内容, 请参阅以下有关本 发明的详细说明与附图, 然而附图仅提供参考与说明用, 并非用来对本发 明加以限制。 附图说明
下面结合附图, 通过对本发明的具体实施方式详细描述, 将使本发明 的技术方案及其它有益效果显而易见。
附图中,
图 1为现有技术中恒流驱动模块驱动 LED灯条的电路图;
图 2为本发明实现 LED灯条电流倍增的方法的流程图;
图 3 为本发明中多个恒流驱动模块同时驱动同一 LED 灯条的电路 图。 具体实施方式
为更进一步阐述本发明所采取的技术手段及其效果, 以下结合本发明 的优选实施例及其附图进行详细描述。
请参阅图 2及 3 , 本发明提供一种实现 LED灯条电流倍增的方法, 包 括以下步骤:
步骤 1、 提供一恒流驱动芯片 30及数个电阻 R, 该恒流驱动芯片 30 具有数个恒流驱动模块 32, 所述每一恒流驱动模块 32 包括第一至第三引 脚 1至 3;
所述电阻 R的阻值根据其对应的 LED灯条 10的所需的亮度来进行选 定, 即通过电阻 R的阻值选定可以调节流过 LED灯条 10的电流, 进而调 节该 LED灯条 10的发光亮度。 在本较佳实施例中, 所述恒流驱动芯片 30 具有恒流驱动模块 32 的数量大于两个, 所述电阻 R的数量对应所述恒流 驱动芯片 30具有的恒流驱动模块 32的数量, 可以保证至少有两个恒流驱 动模块 32同时驱动同一 LED灯条 10。
步骤 2、 提供一 LED灯条 10、 电源 20及 PWM控制源 40, 所述 LED 灯条 10具有一正极及一负极;
该 LED灯条 10包括: 一电路板及设于该电路板上且与该电路板电性 连接的数个 LED灯(未图示) 。
所述 PWM控制源 40输出高电平及低电平, 所述高电平大于该场效应 管 Q正常导通时源极 s上的电压, 所述低电平小于该场效应管 Q正常导通 时源极 s上的电压, 确保在电压比较器 D的正引脚输入高电平时, 可以使 得该电压比较器 D 输出一个高电平驱动场效应管 Q, 并在电压比较器 D 的正引脚输入低电平时, 可以使得该电压比较器输出一个低电平, 而且该 低电平不能导通场效应管 Q; 所述电压比较器 D输出的电压大于该场效应 管 Q的阔值电压, 确保该电压比较器输出的电压可以正常驱动该场效应管 Q, 使得该场效应管 Q在导通与截止状态之间进行转换。
步骤 3、 将一电阻 R—端连接于一恒流驱动模块 32 的第三引脚, 另 一端连接于地线, 将该恒流驱动模块 32的第一引脚 1连接于该 LED灯条 10的负极, 将该恒流驱动模块 32的第二引脚连接于 PWM控制源 40, 并 将 LED灯条 10的正极连接于电源 20;
所述每一恒流驱动模块 32包括: 一场效应管 Q及与该场效应管 Q电 性连接的电压比较器 D, 所述场效应管 Q包括: 一栅极 g、 一源极 s及一 漏极 d, 所述漏极 d与该 LED灯条 10的负极电性连接, 所述栅极 g与电 压比较器 D电性连接, 所述源极 s与该恒流驱动模块 32的第三引脚 3上 的电阻 R电性连接。 通过该场效应管 Q的导通或截止来控制 LED灯条 10 的导通或断开, 安全可靠, 开关寿命长。 所述电压比较器 D 包括: 正引 脚、 负引脚及输出引脚, 所述正引脚与 PWM控制源 40电性连接, 所述负 引脚与该场效应管 Q的源极 s电性连接, 所述输出引脚与该场效应管 Q的 栅极 g电性连接, 通过该电压比较器 D输出一稳定的电压来驱动场效应管
Q。
步骤 4、 根据需要重复步骤 3数次, 使得数个恒流驱动模块 32分别与 该 LED灯条 10、 该数个电阻 R、 该电源 20及该 PWM控制源 40电性连 接;
重复多次步骤 3 , 可以使得多个恒流驱动模块 32 同时驱动同一 LED 灯条 10, 所述多个恒流驱动模块 32对流过 LED 灯条 10 的电流进行分 流, 进而使得流过 LED灯条 10的电流大小不受单个恒流驱动模块 32 的 最大电流的限制。
步骤 5、 接通电源 20及 PWM控制源 40, 利用多个恒流驱动模块 32 同时驱动同一 LED灯条 10进行发光。
本发明采用两个或两个以上的恒流驱动模块 32 同时驱动同一 LED灯 条 10, 可以增加流过 LED灯条 10的电流, 不受单个恒流驱动模块 32的 最大电流的限制, 提高 LED灯条 10的亮度, 产生更高亮度的背光源, 满 足大尺寸液晶显示器的需求。
请参阅图 3 , 本发明还提供一种 LED灯条驱动电路, 包括: 恒流驱动 芯片 30、 数个电阻 R、 一 LED灯条 10、 电源 20及 PWM控制源 40, 该 恒流驱动芯片 30具有数个恒流驱动模块 32, 所述每一恒流驱动模块 32包 括第一至第三引脚 1至 3 , 所述 LED灯条 10具有一正极及一负极, 所述 LED灯条 10的正极与电源 20电性连接, 所述每一电阻 R—端连接于一恒 流驱动模块 32的第三引脚 3上, 另一端连接于地线, 所述接有电阻 R的 恒流驱动模块 32的第一引脚 1都连接于该 LED灯条 10的负极, 第二引 脚 2都连接于 PWM控制源 40。
所述电阻 R的阻值根据其对应的 LED灯条 10的所需的亮度来进行选 定, 即通过调节电阻 R的阻值可以调节流过 LED灯条 10的电流, 进而调 节该 LED灯条 10的发光亮度。 在本较佳实施例中, 所述恒流驱动芯片 30 具有恒流驱动模块 32 的数量大于两个, 所述电阻 R的数量对应所述恒流 驱动芯片 30具有的恒流驱动模块 32的数量, 可以保证至少有两个恒流驱 动模块 32同时驱动同一 LED灯条 10。
所述每一恒流驱动模块 32包括: 一场效应管 Q及与该场效应管 Q电 性连接的电压比较器 D, 所述场效应管 Q包括: 一栅极 g、 一源极 s及一 漏极 d, 所述漏极 d与该 LED灯条 10的负极电性连接, 所述栅极 g与电 压比较器 D电性连接, 所述源极 s与该恒流驱动模块 32的第三引脚 3上 的电阻 R电性连接。 通过该场效应管 Q的导通或截止来控制 LED灯条 10 的导通或断开, 安全可靠, 开关寿命长。 所述电压比较器 D 包括: 正引 脚、 负引脚及输出引脚, 所述正引脚用于与 PWM控制源 40电性连接, 所 述负引脚与该场效应管 Q的源极 s电性连接, 所述输出引脚与该场效应管 Q的栅极 g电性连接, 通过该电压比较器 D输出一稳定的电压来驱动场效 应管 Q。
所述 PWM控制源 40输出高电平及低电平, 所述高电平大于该场效应 管 Q正常导通时源极 s上的电压, 所述低电平小于该场效应管 Q正常导通 时源极 S 上的电压, 确保在正引脚输入高电平时, 可以使得该电压比较器 D输出一个高电平驱动场效应管 Q, 并在正引脚输入低电平时, 可以使得 该电压比较器输出一个低电平, 而且该低电平不能导通场效应管 Q; 所述 电压比较器 D输出的电压大于该场效应管 Q 的阔值电压, 确保该电压比 较器输出的电压可以正常驱动该场效应管 Q, 使得该场效应管 Q在导通与 截止状态之间进行转换。
本发明 LED 灯条驱动电路工作流程: 接通 PWM控制源 40及电源 10, 所述 PWM控制源 10根据实际需要输出高电平, 所述电压比较器 D 输出一高电平驱动场效应管 Q, 所述场效应管 Q由截止状态转变为导通状 态, 所述 LED灯条 10与数个恒流驱动模块 32形成一回路, 驱动 LED灯 条 10发光, 其中, 所述数个恒流驱动模块 32对流过该 LED灯条 10的电 流进行分流。
综上所述, 本发明提供一种实现 LED 灯条电流倍增的方法采用两个 或两个以上的恒流驱动模块同时驱动同一 LED 灯条, 可以增加流过 LED 灯条的电流, 提高 LED 灯条的亮度, 产生更高亮度的背光源, 满足大尺 寸液晶显示器的需求; 本发明 LED 灯条驱动电路结构简单, 提高了流过 LED 灯条的电流, 进而提高 LED 灯条的亮度, 产生更高亮度的背光源, 满足大尺寸液晶显示器的需求。
以上所述, 对于本领域的普通技术人员来说, 可以根据本发明的技术 方案和技术构思作出其他各种相应的改变和变形, 而所有这些改变和变形 都应属于本发明权利要求的保护范围。

Claims

权 利 要 求
1、 一种实现 LED灯条电流倍增的方法, 包括以下步骤:
步骤 1、 提供一恒流驱动芯片及数个电阻, 该恒流驱动芯片具有数个 恒流驱动模块, 所述每一恒流驱动模块包括第一至第三引脚;
步骤 2、 提供一 LED灯条、 电源及 PWM控制源, 所述 LED灯条具 有一正极及一负极;
步骤 3、 将一电阻一端连接于一恒流驱动模块的第三引脚, 另一端连 接于地线, 将该恒流驱动模块的第一引脚连接于该 LED 灯条的负极, 将 该恒流驱动模块的第二引脚连接于 PWM控制源, 并将 LED灯条的正极连 接于电源;
步骤 4、 根据需要重复步骤 3 数次, 使得数个恒流驱动模块分别与该 LED灯条、 该数个电阻、 该电源及该 PWM控制源电性连接;
步骤 5、 接通电源及 PWM控制源, 利用多个恒流驱动模块同时驱动 同一 LED灯条进行发光。
2、 如权利要求 1所述的实现 LED灯条电流倍增的方法, 其中, 所述 恒流驱动芯片具有恒流驱动模块的数量大于两个, 所述电阻的数量对应所 述恒流驱动芯片具有的恒流驱动模块的数量。
3、 如权利要求 2所述的实现 LED灯条电流倍增的方法, 其中, 所述 每一恒流驱动模块包括: 一场效应管及与该场效应管电性连接的电压比较 器, 所述场效应管包括: 一栅极、 一源极及一漏极, 所述漏极与该 LED 灯条的负极电性连接, 所述栅极与电压比较器电性连接, 所述源极与该恒 流驱动模块的第三引脚上的电阻电性连接。
4、 如权利要求 3所述的实现 LED灯条电流倍增的方法, 其中, 所述 电压比较器包括: 正引脚、 负引脚及输出引脚, 所述正引脚与 PWM控制 源电性连接, 所述负引脚与该场效应管的源极电性连接, 所述输出引脚与 该场效应管的栅极电性连接。
5、 如权利要求 4所述的实现 LED灯条电流倍增的方法, 其中, 所述 PWM控制源输出高电平及低电平, 所述高电平大于该场效应管正常导通 时源极上的电压, 所述低电平小于该场效应管正常导通时源极上的电压, 所述电压比较器输出的电压大于该场效应管的阔值电压。
6、 一种 LED 灯条驱动电路, 包括: 恒流驱动芯片、 数个电阻、 一 LED 灯条、 电源及 PWM控制源, 该恒流驱动芯片具有数个恒流驱动模 块, 所述每一恒流驱动模块包括第一至第三引脚, 所述 LED 灯条具有一 正极及一负极, 所述 LED 灯条的正极与电源电性连接, 所述每一电阻一 端连接于一恒流驱动模块的第三引脚上, 另一端连接于地线, 所述接有电 阻的恒流驱动模块的第一引脚都连接于该 LED 灯条的负极, 第二引脚都 连接于 PWM控制源。
7、 如权利要求 6所述的 LED灯条驱动电路, 其中, 所述恒流驱动芯 片具有恒流驱动模块的数量大于两个, 所述电阻的数量对应所述恒流驱动 芯片具有的恒流驱动模块的数量。
8、 如权利要求 6所述的 LED灯条驱动电路, 其中, 所述每一恒流驱 动模块包括: 一场效应管及与该场效应管电性连接的电压比较器, 所述场 效应管包括: 一栅极、 一源极及一漏极, 所述漏极与该 LED 灯条的负极 电性连接, 所述栅极与电压比较器电性连接, 所述源极与该恒流驱动模块 的第三引脚上的电阻电性连接。
9、 如权利要求 6所述的 LED灯条驱动电路, 其中, 所述电压比较器 包括: 正引脚、 负引脚及输出引脚, 所述正引脚与 PWM 控制源电性连 接, 所述负引脚与该场效应管的源极电性连接, 所述输出引脚与该场效应 管的栅极电性连接。
10、 如权利要求 6所述的 LED灯条驱动电路, 其中, 所述 PWM控制 源输出高电平及低电平, 所述高电平大于该场效应管正常导通时源极上的 电压, 所述低电平小于该场效应管正常导通时源极上的电压, 所述电压比 较器输出的电压大于该场效应管的阔值电压。
11、 一种实现 LED灯条电流倍增的方法, 包括以下步骤:
步骤 1、 提供一恒流驱动芯片及数个电阻, 该恒流驱动芯片具有数个 恒流驱动模块, 所述每一恒流驱动模块包括第一至第三引脚;
步骤 2、 提供一 LED灯条、 电源及 PWM控制源, 所述 LED灯条具 有一正极及一负极;
步骤 3、 将一电阻一端连接于一恒流驱动模块的第三引脚, 另一端连 接于地线, 将该恒流驱动模块的第一引脚连接于该 LED 灯条的负极, 将 该恒流驱动模块的第二引脚连接于 PWM控制源, 并将 LED灯条的正极连 接于电源;
步骤 4、 根据需要重复步骤 3 数次, 使得数个恒流驱动模块分别与该 LED灯条、 该数个电阻、 该电源及该 PWM控制源电性连接;
步骤 5、 接通电源及 PWM控制源, 利用多个恒流驱动模块同时驱动 同一 LED灯条进行发光; 其中, 所述恒流驱动芯片具有恒流驱动模块的数量大于两个, 所述电 阻的数量对应所述恒流驱动芯片具有的恒流驱动模块的数量;
其中, 所述每一恒流驱动模块包括: 一场效应管及与该场效应管电性 连接的电压比较器, 所述场效应管包括: 一栅极、 一源极及一漏极, 所述 漏极与该 LED 灯条的负极电性连接, 所述栅极与电压比较器电性连接, 所述源极与该恒流驱动模块的第三引脚上的电阻电性连接;
其中, 所述电压比较器包括: 正引脚、 负引脚及输出引脚, 所述正引 脚与 PWM控制源电性连接, 所述负引脚与该场效应管的源极电性连接, 所述输出引脚与该场效应管的栅极电性连接;
其中, 所述 PWM控制源输出高电平及低电平, 所述高电平大于该场 效应管正常导通时源极上的电压, 所述低电平小于该场效应管正常导通时 源极上的电压, 所述电压比较器输出的电压大于该场效应管的阔值电压。
PCT/CN2012/084996 2012-11-14 2012-11-22 实现led灯条电流倍增的方法及其对应的驱动电路 WO2014075326A1 (zh)

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