1355636 H猶明··:--------------· —~—— 【發明所屬之技術領域】 本發明係關於一種背光模組’特別係關於一種背光模組用的發光二 極體驅動-¾路。 【先前技術】 一般以發光二極體(LightEmittingDiodes ’ LED)作為光源的液晶顯 示裝置，其背面會設置三種不同的發光二極體，這三種發光二極體分 別發出紅、綠'、藍(RGB)三原色的光。將這三原色光混光後會形成一白 色光，該白光照射到液晶顯示裝置之一液晶顯示面板上再經過液晶粒 子的調整形成不同的色彩。該些發光二極體及其相關的驅動電路即設 置在該液晶顯示裝置的一背光模組中。 如第一圖1所示，習知的背光模組包括一驅動電路模組100和複數組 發光二極體ΚΠ。驅動電路模組100内部包括複數組相同之驅動電路。 每一組發光二極體101分別包括一列出射紅、綠、藍三種不同顏色光 線之發光二極體。每一列發光二極體並聯有一穩壓二極體106 *如第二 圖所示，係顯示驅動電路模組100之其中一組驅動電路1〇2驅動其對 應的紅、綠、藍發光二極體列之電路圖，其中每種顏色之發光二極體 列僅代表性地示出其中兩個發光二極體。該驅動電路102包括三個定 流源103,每個定流源103的輸出電流分別經過一對應的脈寬調變 (PWM)開關104，以分別驅動紅、綠、藍三種不同顏色的發光二極 體10卜每一種顏色之發光二極體列並聯有一穩壓二極體106以調節每 但因該驅動電路102採用三個定流源KB，故其效率不高，而且發 光二極體的色度分佈和表鱗度不易控制。此外，因 冷 源及三個脈寬㈣開關，會導_電路發散_量過高且耗電一量大^ 為均勻背光模㈣光的表面輝度分佈，中華民國專利公告第 225958號係在不同列發光二極體中加人不同限流電阻但該方式於實 現背光模組出光的色度控制上翻難，而且其驅動電路效率不高。 為提高驅動電路的效率，美國專利公告第逝1〇5號揭示了 一種驅 動電路，其中红色和綠色的發光二極體共用—個恒壓源，藍色發光二 極體單姻-個恒壓源，但該驅動電路中發光二極體的發光能量比例 不可調節，所以能夠達到的色域比較小。 因此，確有必要提供-觀良的驅動電路制時克服前述習知技術 中的眾多缺陷。 【發明内容】 本發明之-目的在於提供-種效率較高而且㈣調節發光二極體 輝度及色度的發光二極體驅動電路。 本發明之另-目的在於提供-種背光模組，其具有效率較高而且易 於調節發光二極體輝度及色度的發光二極體驅動電路。 為實現上述目的’本發明係提供-種發光二極體驅動電路，其設於 —背光模組中用以驅動發光二極體’該發光二極體驅動電路包括一定 流源及三個脈寬調變關。該定流源肋輪^具恒定電流值的電 1355636 流。三―個脈复讀髮開關分方丨連接1¾¾¾:源至土：種出射不1¾¾色光故爵 發光二極體。該三個脈寬調變開關依序進行閉合、斷開的切換，該定 流源輸出的電流經過被依序切換的三個脈寬調變開關，分時驅動該三 種出射不同顏色光線的發光二極體進行發光。 為實現上述目的，本發明一種背光模組，其包括三組分別出射不 同顏色光線的發光二極體以及一驅動電路，用以驅動發光二極體。該 驅動電路包括一定流源及三個脈寬調變開關。該定流源用以輸出一具 恒定電流值的電流。三個脈寬調變開關分別連接該定流源至三種出射 不同顏色光線的發光二極體。該三個脈寬調變開關依序進行閉合、斷 開的切換，該定流源輸出的電流經過被依序切換的三個脈寬調變開 關，分時驅動該三種出射不同顏色光線的發光二極體進行發光。 相較於習知技術，本發明僅採用一個定流源通過三個脈寬調變開 關’即能分時驅動三組不同顏色的發光二極體，使用的元件數量遠較 習知電路減少，故能節省成本；同時也能降低電路的發熱量。其中進 一步利用分時控制該三組發光二極體，可節省系統電力，故能大幅提 昇電路效率。另外由於脈寬調變開關可調整脈衝的寬度，所以可調節 背光的色度和控制背光的輝度β 【實施方式】 請參閱第三圖所示，本發明之以發光二極體(LED)作為光源的背光 模組，其包括一驅動電路模組30及複數組分別出射紅、綠、藍(Rgb) 三原色光的發光二極體光源17、18、19。每一驅動電路模組包括複數 組相同之發光二極體驅動電路1〇。以下舉其中一組發光二極體驅動電 7 10驅^-，4紅、綠、藍獅的私二猛體光廉為娜以說明，其中 每種顏色之發光二極體僅代表性地示出兩個。 。用參閱第四圖所示，本發明的發光二極體驅動電路1〇包括一定流 源11，當一外部電源的電流經過該定流源11整流後，自該定流源11 輸出-具恒定電流值的電流在本實施方式中該定流源u係採用一積 體電路模組12(本實施例中使用一型號為，’LM317T”的1C)，其中該積體 電路模組12的一訊號端2與一電源輸入端㈤相連，另 一訊號端3則 用於輸出電流，在兩訊號端1與3之間連接有-限流電阻13，用以調 即電流的大小。三個脈寬調變(PWM)開關14、15、16分別連接該定流 源11和紅、綠、藍(RGB)三組不同顏色的發光二極體17、18、19。該 -個脈寬調變_ 14、15、16依序進行閉合、斷開的切換，同一時刻 内最多只有其巾的—個Μ是閉合的 。經定流源11整流之後的輸出電 机分別經過被依序切換的三個脈寬調變開關14、15、16 ，以形成脈衝1355636 HJiumin··:--------------·-~—— [Technical Field of the Invention] The present invention relates to a backlight module, particularly for a backlight module The light-emitting diode drive -3⁄4 way. [Prior Art] Generally, a liquid crystal display device using a light emitting diode (LED) as a light source is provided with three different light emitting diodes on the back surface, and the three light emitting diodes respectively emit red, green, and blue (RGB). The light of the three primary colors. When the three primary colors are mixed, a white light is formed, which is irradiated onto one of the liquid crystal display panels of the liquid crystal display device and then adjusted to form different colors by the liquid crystal particles. The light emitting diodes and related driving circuits are disposed in a backlight module of the liquid crystal display device. As shown in FIG. 1 , the conventional backlight module includes a driving circuit module 100 and a complex array of LEDs. The driving circuit module 100 internally includes a driving circuit having the same complex array. Each of the groups of light-emitting diodes 101 respectively includes a light-emitting diode which lists three different color lines of red, green and blue. Each column of light-emitting diodes has a voltage stabilizing diode 106 connected in parallel. * As shown in the second figure, one of the driving circuit blocks 1 of the driving circuit module 100 drives the corresponding red, green and blue light-emitting diodes. A circuit diagram of a body array in which the column of light-emitting diodes of each color only representatively shows two of the light-emitting diodes. The driving circuit 102 includes three constant current sources 103, and the output current of each of the constant current sources 103 passes through a corresponding pulse width modulation (PWM) switch 104 to respectively drive three different colors of red, green and blue. The polar body 10 has a voltage stabilizing diode 106 connected in parallel with each color column to adjust each of the three fixed current sources KB of the driving circuit 102, so the efficiency is not high, and the light emitting diode is Chromaticity distribution and table scalarity are not easy to control. In addition, due to the cold source and three pulse width (four) switches, the conduction _ circuit divergence _ the amount is too high and the power consumption is large. ^ The surface luminance distribution of the uniform backlight mode (4) light, the Republic of China Patent Notice No. 225958 is different Different current limiting resistors are added to the column light-emitting diodes, but this method is difficult to achieve the chromaticity control of the backlight module, and the driving circuit is not efficient. In order to improve the efficiency of the driving circuit, U.S. Patent Publication No. 1〇5 discloses a driving circuit in which red and green light emitting diodes share a constant voltage source, and blue light emitting diodes are single marriage-one constant voltage. Source, but the ratio of the luminous energy of the light-emitting diode in the driving circuit is not adjustable, so the color gamut that can be achieved is relatively small. Therefore, it is indeed necessary to provide a good drive circuit to overcome many of the aforementioned drawbacks of the prior art. SUMMARY OF THE INVENTION The present invention has an object to provide a light-emitting diode driving circuit which has high efficiency and (4) adjusts luminance and chromaticity of a light-emitting diode. Another object of the present invention is to provide a backlight module which has a high efficiency and is easy to adjust the luminance and chromaticity of the LED. In order to achieve the above object, the present invention provides a light-emitting diode driving circuit, which is disposed in a backlight module for driving a light-emitting diode. The light-emitting diode driving circuit includes a certain current source and three pulse widths. Change the off. The constant current source rib wheel has a constant current value of 1355636 flow. Three - a pulse repeat switch switch 丨 connection 13⁄43⁄43⁄4: source to earth: the type of emission is not 13⁄43⁄4 color light, the light-emitting diode. The three pulse width modulation switches sequentially switch between closing and opening, and the current output by the constant current source passes through three pulse width modulation switches that are sequentially switched, and the three kinds of light emitting different colors of light are driven by time sharing. The diode emits light. In order to achieve the above object, a backlight module of the present invention comprises three sets of light emitting diodes respectively emitting light of different colors and a driving circuit for driving the light emitting diodes. The drive circuit includes a fixed current source and three pulse width modulation switches. The constant current source is used to output a current having a constant current value. Three pulse width modulation switches are respectively connected to the constant current source to three light emitting diodes that emit light of different colors. The three pulse width modulation switches sequentially switch between closing and opening, and the current output by the constant current source passes through three pulse width modulation switches that are sequentially switched, and the three kinds of light emitting different colors of light are driven by time sharing. The diode emits light. Compared with the prior art, the present invention uses only one constant current source to drive three sets of light-emitting diodes of different colors through three pulse width modulation switches, and the number of components used is much smaller than that of conventional circuits. Therefore, it can save costs; at the same time, it can also reduce the heat generation of the circuit. Further, by using the time-sharing control of the three groups of light-emitting diodes, system power can be saved, so that the circuit efficiency can be greatly improved. In addition, since the pulse width modulation switch can adjust the width of the pulse, the chromaticity of the backlight can be adjusted and the luminance of the backlight can be controlled. [Embodiment] Referring to the third figure, the present invention uses a light-emitting diode (LED) as a light-emitting diode. The backlight module of the light source comprises a driving circuit module 30 and a plurality of light emitting diode light sources 17, 18, 19 respectively emitting red, green and blue (Rgb) primary colors. Each of the driving circuit modules includes a plurality of identical LED driving circuits. The following is a set of light-emitting diode driving electric 7 10 drive ^ -, 4 red, green, blue lion's private two violent body light to illustrate, in which each color of the light-emitting diode is representatively shown Two. . As shown in the fourth figure, the LED driving circuit 1 of the present invention includes a constant current source 11. When the current of an external power source is rectified by the constant current source 11, the output from the constant current source 11 is constant. In the present embodiment, the current source u is an integrated circuit module 12 (1C used in the present embodiment, model 'LM317T'), wherein one of the integrated circuit modules 12 The signal terminal 2 is connected to a power input terminal (5), and the other signal terminal 3 is used for outputting current. A current limiting resistor 13 is connected between the two signal terminals 1 and 3 for adjusting the magnitude of the current. Wide-tuning (PWM) switches 14, 15, 16 are respectively connected to the constant current source 11 and red, green, and blue (RGB) three sets of different colors of the light-emitting diodes 17, 18, 19. The pulse width modulation _ 14, 15, 16 sequentially switch between closing and breaking. At the same time, at most, only one of the towels is closed. The output motor after rectification by the constant current source 11 passes through the three sequentially switched. Pulse width modulation switches 14, 15, 16 to form a pulse
Bfim、綠 '雖GB)三組不同顏色的發光二極體17、18、 19發光。在定流源11的輸出端的10埠和三組不同顏色發光二極體17、 18丨9的輸出端之間並聯有一穩壓二極體2〇，以調整該三組發光二極 體P、18、19的電壓。 明參閱第四及第五圖所示。經定流源n輸出的恒定電流在經過三 個脈寬調變開關14、15、16時，該三個脈寬調變開關i4、i5、16的 閉°和_的_依順序相互錯開。如第五®所示，在-特定時間週 期内按順序先使紅色發光二極體17的脈寬調變開關Μ閉合，產生 1355636 -驅動紅-色蘇g祖爾ψ函 色發光二極體18的脈寬調變開關15閉合，產生一驅動綠色發光二極 體18的脈衝電流之後該開關15斷開。再之後使藍色發光二極體19的 脈寬調變開關16閉合’產生-驅動藍色發光二極體19的脈衝電流之 後該開關16斷開。藉此’該三組不同顏色的發光二極體〗7、i8、i9 可達到分時點亮之目的。雖触、綠、藍三色發光二極體ΐ7、Μ、Μ 係分別點亮，但由於該脈衝的頻率很高，而加上人眼反應的情性，只 要紅、綠、藍三色的能量蘭搭配適#，人喊終看觸還是白光。 而且如第五圖所示，每組脈衝中，紅、綠、藍三色發光二極體的驅動 脈衝的前後沿之間仍間隔有-距離，並非緊密相連的連續的脈衝，這 樣可以產生-時間間隙，從而亦可根據需要通過控制脈寬調變開關 14、15、16的閉合和斷開的時間長度來調整脈衝的持續時間（即圖中 脈衝的寬度），從而使得脈衝的__可調，則發光二極體獲得的能 量也可調，因此可以根據需要來背光模組出光的色度和輝度。 如第六圖所示’為依據本發明另一較佳實施例的背光模組驅動方式 的示意圖。驅動電路模組30’用以驅動複數組紅綠藍三色發光二極體 17、18’、19’ ’並在某些顏色的發光二極體列中並聯適宜的分流電阻， 從而調節背光模組中不同顏色光線的能量的比例，以進一步控制和調 整背光模組出光的色度和輝度。例如第六圖中―藍色發光二極體⑼列 係並聯有-個分流電阻21，。藉由該脈寬調變開關控制脈衝的時間長短 再加上該分Μ阻，更枝控制不同發光二極_能量，以將發光二 極體的色度和輝度調整到需要^範圍Γ一 一…一——-- 本發明的驅動電路只使用-個定流源，因此能提高驅動電路的驅動 效率。且只有一個疋流源和一個穩壓二極體發熱，發熱量較小，使用 的元器件較少’從而可節省電能。另外，由於本發明驅動電路的輸出 脈衝的寬度可由脈寬調變開關控制，因此能方便的調節發光二極體的 能量，從而方便地調整和控制背光模組出光的色度和輝度。 綜上所述，本發明確已符合發明專利之要件，爰依法提出專利申 請。惟，以上所述者僅爲本發明之較佳實施方式，舉凡熟習本案技術 之人士援依本發明之精神所作之等效修飾或變化，皆涵蓋於後附之申 請專利範圍内。 【圖式簡單說明】 第一圖係習知的背光模組驅動方式示意圖》 第二圖係習知的背光模組中其中一組發光二極體驅動電路的示意 圖。 第三圖係本發明的背光模組驅動方式示意圖。 第四圖係本發明的背光模組中其中一組發光二極體驅動電路的示 意圖》 第五圖係本發明中驅動電路所發出的脈衝的示意圖。 第六圖係本發明另一實施例之背光模組驅動方式的示意圖。 【主要元件符號說明】 1355636 1,2,3 — 訊誕端 100 一 驅動電路模組 10, 102 驅動電路 101 發光二極體 103 定流源 104 脈寬調變開關 11 定流源 12 積體電路模組 13 限流電阻 14, 15, 16 脈寬調變開關 17,18, 19 發光二極體 14’，15，，16， 脈寬調變開關 17，，18’，19， 發光二極體 20, 106 穩壓二極體 21， 分流電阻 30, 30’ 驅動電路模組 11Bfim, green 'While GB', three sets of different color LEDs 17, 18, 19 emit light. A voltage stabilizing diode 2 is connected in parallel between the output terminal of the constant current source 11 and the output terminals of the three sets of different color light emitting diodes 17, 18丨9 to adjust the three sets of light emitting diodes P, 18, 19 voltage. See the fourth and fifth figures for clarity. When the constant current outputted from the constant current source n passes through the three pulse width modulation switches 14, 15, 16 , the closing degrees of the three pulse width modulation switches i4, i5, and 16 are sequentially shifted from each other. As shown in the fifth®, the pulse width modulation switch 红色 of the red light-emitting diode 17 is first closed in a specific time period to generate a 1355636-driven red-color Su-Gurzen light-emitting diode. The pulse width modulation switch 15 of 18 is closed, and the switch 15 is turned off after generating a pulse current for driving the green light emitting diode 18. Thereafter, the pulse width modulation switch 16 of the blue light-emitting diode 19 is closed. The switch 16 is turned off after the pulse current of the blue light-emitting diode 19 is generated. Therefore, the three sets of different color LEDs 7, i8, i9 can achieve the purpose of time-division lighting. Although the touch, green, and blue light-emitting diodes ΐ7, Μ, and Μ are respectively lit, but because of the high frequency of the pulse, and the emotional response of the human eye, as long as the red, green, and blue colors Energy Lan is suitable for #, people call it or white light. Moreover, as shown in the fifth figure, in each group of pulses, the front and rear edges of the driving pulses of the red, green and blue light-emitting diodes are still separated by a distance, which is not a continuous pulse which is closely connected, so that - The time gap, so that the duration of the pulse (ie the width of the pulse in the figure) can be adjusted by controlling the length of the closing and opening of the pulse width modulation switches 14, 15, 16 as needed, so that the pulse __ can be The energy obtained by the LED is also adjustable, so the chromaticity and luminance of the backlight module can be selected as needed. As shown in the sixth figure, a schematic diagram of a driving method of a backlight module according to another preferred embodiment of the present invention is shown. The driving circuit module 30' is configured to drive the complex array of red, green and blue three-color LEDs 17, 18', 19'' and connect appropriate shunt resistors in the LED array of certain colors to adjust the backlight mode. The ratio of the energy of the different color rays in the group to further control and adjust the chromaticity and luminance of the backlight module. For example, in the sixth figure, the blue light-emitting diode (9) has a shunt resistor 21 connected in parallel. By controlling the pulse length of the pulse width modulation switch and adding the branching resistance, the different light-emitting diodes are controlled to adjust the chromaticity and luminance of the light-emitting diode to the required range. ... one--- The driving circuit of the present invention uses only one constant current source, so that the driving efficiency of the driving circuit can be improved. Only one turbulent source and one regulated diode generate heat, generate less heat, and use fewer components' to save energy. In addition, since the width of the output pulse of the driving circuit of the present invention can be controlled by the pulse width modulation switch, the energy of the light emitting diode can be conveniently adjusted, thereby conveniently adjusting and controlling the chromaticity and luminance of the light emitted by the backlight module. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are included in the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The first figure is a schematic diagram of a conventional backlight module driving method. The second figure is a schematic diagram of one of the light-emitting diode driving circuits in the conventional backlight module. The third figure is a schematic diagram of the driving mode of the backlight module of the present invention. The fourth drawing is a schematic diagram of one of the light-emitting diode driving circuits in the backlight module of the present invention. The fifth drawing is a schematic diagram of pulses emitted by the driving circuit in the present invention. FIG. 6 is a schematic diagram of a driving method of a backlight module according to another embodiment of the present invention. [Main component symbol description] 1355636 1,2,3 — Signal terminal 100 A driver circuit module 10, 102 Drive circuit 101 Light-emitting diode 103 Current source 104 Pulse width modulation switch 11 Current source 12 Integrated circuit Module 13 Current limiting resistor 14, 15, 16 Pulse width modulation switch 17, 18, 19 Light-emitting diode 14', 15, 16, 16, Pulse width modulation switch 17, 18', 19, LED 20, 106 voltage regulator diode 21, shunt resistor 30, 30' drive circuit module 11