200839709 九、發明說明： 【發明所屬之技術領域】 本發明係關於-種光源組，特別是關於—種利用一回 授電路產生保護機制之發光二極體(LED)光源組。 【先前技術】 非自％光性的顯不面板，例如液晶面板，通常需要^一 背光源才得以進行影像的顳示。在習知諸多種背光源技術 中，側端入光的背光模組傳符合於產品薄型化的需求。 〃 請參照圖一，圖一為習知背光模組中，光源組i與導 光板50的示意圖。所謂側端入光的背光模組，係將光源組 1設置在導光板50的一側端52,此側端52即為導光板50 的入光面。光源組1所發出之光線係由導光板5〇之侧端 52進入導光板50。光線在導光板5〇内因介面全反射而散 射其中，最後由一出光面51射出導光滅5〇，以便提供一 均勻约:句光源予一顯示面板(圖中未顯示)使用。 光源組1中具有複數個發光二極體11〗，且這些發光 一極體111係設置於一基板1〇上，用以提供入射到導光板 5〇之光線。其中，發光二極體m是一種將電能轉換成光 能的元件，目前最常使用的發光二極體為白光LED。另 外’在基板10的選用上，一般為散熱鋁基板。 圖一係為習知光源組之電路示意圖。光源組包括複數 組發光二極體串(LED string)21及一驅動晶片22。 每一發光二極體串21係由複數個發光二極體2U所串 6 200839709 聯而成。每—發光二極體串21之正極端連接至—輸入電承 Vm ’而負極端則以—導線與驅動晶片22連接。因此，二 =輸入電壓Vin與驅動晶片22的作用，可對各發光二極^ 知加電壓與電流，以達到發光的效果。在習知技術 中—個驅動晶片22可連接複數組發光二極體串21，且 可依貫際需求來增加發光二極體串21的數目。 —般來說’發光二極體串21係為並聯的型態，所以輪 入每一發光二極體串21的輸入電壓Vin亦皆相同。因此， 在任二發光二極體串21中，若有發光二極體211發生損壤 的情形，則原本應落在此發光二極體211的電壓，就必^ 由驅動22來承擔。也就是說，發光上極體211的損壤) 會使驅動晶片22產生額外的電壓負擔。 然]而，驅動晶片22所能負擔的電壓是有限的，若過多 的電壓落在驅動晶片22，則驅動晶片22會產生發熱，甚 至損壞的情形，更嚴重者，亦可能連帶造成其他正常發光 二極體211的損壞。 爰是’鑑於上述習知技術中不足之處，對此提供〜貧 際有效的方案，.係為當前技術所必需。 【發明内容】 本發明之一目的係在於藉由在每一發光二極體串增力π 一回授電路，來避免因為發光二極體損壞而造成驅動晶片 產生額外的電壓負擔的情形，以確保驅動晶片的正常運作。 本發明提供一種光源組，可應用於背光模組，包括〜 7 200839709 驅動晶片、至少一開關元件'至少一組發光二極體串及至 少一比較器。 其中，驅動晶片，設置於一基板上。關元件，具有 %/ 一第一端與一第二端，且第一端連接至驅動晶片。發光二 極體串(LED string)，係由複數個發光二極體(LED)串聯而 成，且發光二極體串的一端電性連接至開關元件之第二 端，並透過開關元件耦接至驅動晶片，另一端則是連接至 一輸入電壓Vin。 ⑩ 比車父态，係具有一第一輸入端、一第二輸入端。比較 器之第一輸入端電性連接至開關元件之第二端。一參考電 壓Vref透過第二輸入端輸入至比較器，使比較器輸出一比 較Λ號至驅動晶片，其中驅動晶片係藉由比較訊號使開關 元件接通/斷路。 當第一輸入端之電壓大於第二輸入端之參考電壓時， 比較器輸出至驅動晶片的比較訊號將驅使驅動晶片使開關 元件斷路，而使所連接之發光二極體串無法導通。 • 關於本發明之優點與精神，以及更詳細的實施方式可 以藉由以下的實施方式以及所附圖式得到進一步的瞭解。 【實施方式】 請參照圖三，圖三係為本發明光源組之電路示意圖。 ^ 光源組包括一驅動晶片32、一開關元件33、一組發光二極 ^ 體串31及一比較器34。 驅動晶片32 ’係設置於一基板(圖中未顯示)上。開關 8 200839709 兀件33，具有一第一端331與一第二端332，且第一端331 連接至驅動U 32。發光二極射(LEDString)31，係由複 數個^光_極體(LED)311 φ聯而成，且發光二極體串31 v 的端包性連接至開關元件33之第二端332，並透過開關 兀件33經由第一端331耦接至驅動晶片。而發光二極 體串31之另一端則是連接至一輸入電壓細。其中，發光 二極體串31連接至輸入電壓Vin之一端為正極端，連接至 開關=件33之第二端332之一端為負極端。另外，目前常 φ 用作背光源之發光二極體係為白光LED。 另外，開關元件33更具有一第三端333，用以連接至 接地端(GND)。其巾，第三端係透過一具有阻抗元件之線 路連接至接地端(GND)。在一較佳實施例中，此開關元件 33係為- M0S元件，第-端331 a閘極、第二端332為源 極及第三端333為沒極。 因此，光源組的發光係藉由驅動晶片22驅使開關元件 33導通，以及輸入電壓Vin的作用，對發光二極體串31 ⑩ 之所有發光二極體211施加電壓與電流，以達到發光的效 比較器34，係具有一第一輸入端341、一第二輸入端 342及一輸出端343。比較器34之第一輸入端341電性連 接至開關元件33之第二端332。其中，連接至第一輸入端 341之線路係透過一具有阻抗元件之電路連接至一節點 A’此師點A係位於發光二極體串31之負極端連接至開關 奢 元件33第二端332之線路上。 所以，發光二極體串31之負極端、節點a及開關元 9 200839709 件33之第二端332係具有相同的電壓位準，而比較器％ . 之第一輸入端341亦具有與上述電壓位準相同或等_ (經由節點A至第一輸入端341電路間的阻抗作用）之電壓 、 位準。值得注意的是，節點A之電壓位準亦即驅動晶片32 所負擔之電壓大小，也就是說第一輸入端341之電壓位準 亦即驅動晶片32所負擔之電壓的等比例縮放。 一參考電壓Vref透過第二輸入端342輸入至比較器 34。此日可比較态34係依照第二輸入端342之參考電壓vref _ 與第一輸入端341之電壓位準，而輸出一比較訊號至驅動 晶片32，而驅動晶片32即藉由此比較訊號使開關元件33 接通或斷路。 ' 在本發明之實施例中，當發光二極體串31中有發光二 極體311發生損壞的情況時，節點A的電壓位準會增加， 也就是驅動晶片32所負擔之電壓變大，而很有可能造成驅 動晶片32的毁損。 為了避免上述問題的產生，在本發明實施例中當第一 _ 輸入端341之電壓位準大於第二輸入端342之參考電壓BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source group, and more particularly to a light-emitting diode (LED) light source group that utilizes a feedback circuit to generate a protection mechanism. [Prior Art] A panel that is not self-lighting, such as a liquid crystal panel, usually requires a backlight to enable image display. Among the various backlight technologies known in the art, the backlight module of the side-end light is transmitted in accordance with the demand for thinning of the product. 〃 Referring to FIG. 1 , FIG. 1 is a schematic diagram of a light source group i and a light guide plate 50 in a conventional backlight module. The backlight module of the side end light is disposed on one side end 52 of the light guide plate 50, and the side end 52 is the light incident surface of the light guide plate 50. The light emitted by the light source group 1 enters the light guide plate 50 from the side end 52 of the light guide plate 5. The light is scattered in the light guide plate 5〇 by the total reflection of the interface, and finally the light guide 51 is emitted by the light exiting surface 51 to provide a uniform light source for use in a display panel (not shown). The light source group 1 has a plurality of light-emitting diodes 11 and the light-emitting diodes 111 are disposed on a substrate 1 to provide light incident on the light guide plate 5 . Among them, the light-emitting diode m is an element that converts electrical energy into light energy, and the most commonly used light-emitting diode is a white light LED. In addition, in the selection of the substrate 10, a heat dissipating aluminum substrate is generally used. Figure 1 is a schematic diagram of a circuit of a conventional light source group. The light source set includes a plurality of LED strings 21 and a drive wafer 22. Each of the light-emitting diode strings 21 is formed by a plurality of light-emitting diodes 2U string 6 200839709. The positive terminal of each of the LED strings 21 is connected to the input terminal Vm' and the negative terminal is connected to the driver wafer 22 by wires. Therefore, the voltage of the input voltage Vin and the driving wafer 22 can be applied to the respective light-emitting diodes to increase the voltage and current to achieve the effect of light emission. In the prior art, a driving chip 22 can be connected to the complex array of light emitting diode strings 21, and the number of light emitting diode strings 21 can be increased according to the requirements. In general, the light-emitting diode strings 21 are in a parallel configuration, so that the input voltage Vin of each of the light-emitting diode strings 21 is also the same. Therefore, in any of the two-light-emitting diode strings 21, if the light-emitting diode 211 is damaged, the voltage originally falling on the light-emitting diode 211 must be borne by the drive 22. That is to say, the damage of the illuminating upper body 211 causes an additional voltage load on the driving wafer 22. However, the voltage that the driving chip 22 can bear is limited. If too much voltage falls on the driving wafer 22, the driving of the wafer 22 may cause heat generation or even damage, and more serious, may cause other normal illumination. Damage to the diode 211. In view of the deficiencies in the above-mentioned prior art, it is necessary to provide a solution that is effective in the prior art. SUMMARY OF THE INVENTION One object of the present invention is to avoid the situation in which the driving chip generates an additional voltage burden due to the damage of the light emitting diode by increasing the force π a feedback circuit in each of the light emitting diode strings. Ensure the normal operation of the driver chip. The invention provides a light source set, which can be applied to a backlight module, comprising: ~ 7 200839709 driving chip, at least one switching element 'at least one set of LED strings and at least one comparator. The driving chip is disposed on a substrate. The off component has a %/first end and a second end, and the first end is connected to the drive wafer. The LED string is formed by connecting a plurality of LEDs in series, and one end of the LED string is electrically connected to the second end of the switching element and coupled through the switching element. To drive the chip, the other end is connected to an input voltage Vin. 10 has a first input end and a second input end than the parent state. The first input of the comparator is electrically connected to the second end of the switching element. A reference voltage Vref is input to the comparator through the second input terminal, so that the comparator outputs a comparison signal to the driving chip, wherein the driving chip is used to turn the switching element on/off by comparing signals. When the voltage at the first input is greater than the reference voltage at the second input, the comparison signal output by the comparator to the drive wafer will drive the drive wafer to open the switching element and disable the connected LED strings. The advantages and spirit of the present invention, as well as the more detailed embodiments, may be further understood by the following embodiments and the accompanying drawings. [Embodiment] Please refer to FIG. 3, which is a schematic circuit diagram of a light source group of the present invention. The light source group includes a driving chip 32, a switching element 33, a set of light emitting diode strings 31, and a comparator 34. The drive wafer 32' is disposed on a substrate (not shown). The switch 8 200839709 has a first end 331 and a second end 332, and the first end 331 is connected to the drive U 32. The LED string 31 is formed by a plurality of LEDs 311 φ, and the end of the LED string 31 v is connected to the second end 332 of the switching element 33. And coupled to the driving wafer via the first end 331 through the switch member 33. The other end of the LED string 31 is connected to an input voltage. The light-emitting diode string 31 is connected to one end of the input voltage Vin to be a positive terminal, and one end of the second terminal 332 connected to the switch=piece 33 is a negative terminal. In addition, the current φ system used as a backlight is a white LED. In addition, the switching element 33 further has a third end 333 for connection to the ground (GND). The third end of the towel is connected to the ground (GND) through a line having an impedance element. In a preferred embodiment, the switching element 33 is a - MOS element, the first end 331 a is a gate, the second end 332 is a source, and the third end 333 is a pole. Therefore, the illumination of the light source group is driven by the driving of the wafer 22 to drive the switching element 33 and the input voltage Vin to apply voltage and current to all of the LEDs 211 of the LED array 31 10 to achieve illumination efficiency. The comparator 34 has a first input terminal 341, a second input terminal 342 and an output terminal 343. The first input 341 of the comparator 34 is electrically coupled to the second terminal 332 of the switching element 33. Wherein, the circuit connected to the first input terminal 341 is connected to a node A' through a circuit having an impedance element. The point A is located at the negative end of the LED string 31 and connected to the second end 332 of the switch element 33. On the line. Therefore, the negative terminal of the LED string 31, the node a, and the second terminal 332 of the switch element 9 200839709 33 have the same voltage level, and the first input 341 of the comparator % also has the above voltage. The voltage or level of the same level or equal _ (impedance through the circuit between node A and the first input 341 circuit). It should be noted that the voltage level of the node A is also the voltage that the driving chip 32 bears, that is, the voltage level of the first input terminal 341, that is, the voltage proportional to the voltage that the driving chip 32 is burdened. A reference voltage Vref is input to the comparator 34 through the second input terminal 342. The comparable state 34 outputs a comparison signal to the driving chip 32 according to the voltage level of the reference voltage vref_ of the second input terminal 342 and the first input terminal 341, and the driving chip 32 is thereby compared by the signal. The switching element 33 is turned on or off. In the embodiment of the present invention, when the light-emitting diode 311 is damaged in the light-emitting diode string 31, the voltage level of the node A is increased, that is, the voltage applied to the driving chip 32 is increased. It is highly likely that the drive wafer 32 is damaged. In order to avoid the above problem, in the embodiment of the present invention, the voltage level of the first_input terminal 341 is greater than the reference voltage of the second input terminal 342.
Vref時，比較器34輸出至驅動晶片32的比較訊號將驅使 驅動晶片32使開關元件33斷路，以防止驅動晶片32所承 受的電壓過大。 當然，當第一輸入端341之電壓位準小於或等於第二 輸入端342之參考電壓Vref時，比較器34輸出至驅動晶 . 片32的比較訊號將驅使驅動晶片32使開關元件持續導通。 v 其中，比較器34第一輸入端341之電壓位準係對應於 200839709 驅動晶片32所負擔的電壓大小，而參考電壓yref係對鹿 於驅動晶片32所能負擔的電壓大小。 所以’上述的開關元件33、比較器34、節點A至比 較器34之第一輸入端341之電路結構即構成一回授電路， 用以保護驅動晶片32。一旦第一輸入端341之電壓位準大 於第二輸入端342之參考電壓Vref時，代表驅動晶片32 正承受大於其所能承擔的電壓大小。此時，比較器34隨即 輸出比較訊號驅使驅動晶片32使開關元件33斷路，以關 閉此開關元件33所連接之發光二極體串31。藉此，達到 保護驅動晶片32的功效。 在上述實施例中，雖僅以一組發光二極體串31來做介 I。但貫際應用上，光源組係具有複數組的發光二極體串 31連接至一個驅動晶片上32，同時每一組發光二極體串 31皆具有各自的回授電路，也就是分別連接至各自的開關 元件及比較器。 當任一組發光二極體串31内的發光二極體311損壞過 多二而造成驅動晶片32電壓負擔過大時，驅動晶片32就 έ藉由回授電路所提供的比較訊號，使連接至此發光二極 體串31之開關元件33斷路，以關閉此發光二極體串31。 然而此時，其他發光二極體串31仍·具續正常發亮中。 也就是說’本發明之光源组，雖可能因為關閉某些有 問題的發光二極體串，而造成亮度稍減。但卻可以有效避 免因為驅動晶片損毁，而造成整個光源組失效的風險。 11 200839709 綜上所述，本發明所提供之光源組中，係對每一發光 二極體串增加一回授電路。當某一發光二極體串中之發光 _ 二極體有損壞，而造成驅動晶片產生額外的電壓負擔的情 V 形時，回授電路會給予驅動晶片一比較訊號，使驅動晶片 關閉與此發光二極體串的連線狀態。藉此，避免驅動晶片 有過熱而損壞的情形，以確保驅動晶片的正常運作。 在貫際應用上’本發明之光源組不僅可應用於側端入 光的背光模組，亦可應用於直下式背光模組。在一實施例 • 中，直下式背光模組的背光源係可由複數個光源組並排且 整合而成。 本發明雖以較佳實例闡明如上，然其並非用以限定本 發明精神與發明實體僅止於上述實施例爾。對熟悉此項技 術者，，可輕易了解並利用其它元件或方式來產生相同的 功效。是以，在不脫離本發明之精神與範圍内所作之修改， 均應包含在下述之申請專利範圍内。 ® 【圖式簡單說明】 藉由以下詳細之描述結合所附圖示，將可輕易的了解 上述内容及此項發明之諸多優點，其中： 圖一係為f知背絲財，辆、轉導歧的示意圖； 圖一係為習知光源組之電路示意圖；及 " 圖二係為本發明光源組之電路示意圖。 【主要元件符號說明】· 200839709 光源組i 基板10 - 發光二極體串11、21、31 v 發光二極體1Π、211、311 導光板50 出光面51 侧端52 驅動晶片22、32 開關元件33 • 第一端331 第二端332 第三端333 比較器34 第一輸入端341 第二輸入端342 輸入電壓Vin 輸出電壓Vref 13At Vref, the comparison signal output by comparator 34 to drive die 32 will drive drive die 32 to open switch element 33 to prevent excessive voltages on drive die 32. Of course, when the voltage level of the first input terminal 341 is less than or equal to the reference voltage Vref of the second input terminal 342, the comparison signal output from the comparator 34 to the driving transistor 32 will drive the driving chip 32 to continuously turn on the switching element. v, wherein the voltage level of the first input terminal 341 of the comparator 34 corresponds to the voltage that the driver chip 32 is responsible for in 200839709, and the reference voltage yref is the voltage that the deer can afford to drive the chip 32. Therefore, the circuit structure of the above-mentioned switching element 33, comparator 34, node A to the first input terminal 341 of the comparator 34 constitutes a feedback circuit for protecting the driving chip 32. Once the voltage level of the first input 341 is greater than the reference voltage Vref of the second input 342, it is representative that the drive die 32 is being subjected to a voltage greater than it can. At this time, the comparator 34 outputs a comparison signal to drive the driving chip 32 to open the switching element 33 to turn off the LED string 31 to which the switching element 33 is connected. Thereby, the effect of protecting the driving chip 32 is achieved. In the above embodiment, only one set of the light-emitting diode strings 31 is used as the medium. However, in a continuous application, the light source group has a plurality of LED arrays 31 connected to a driving chip 32, and each group of LED strings 31 has its own feedback circuit, that is, respectively connected to Respective switching elements and comparators. When the light-emitting diodes 311 in any one of the LED strings 31 are damaged too much and the voltage burden of the driving chip 32 is too large, the driving chip 32 is connected to the light by the comparison signal provided by the feedback circuit. The switching element 33 of the diode string 31 is opened to close the LED string 31. At this time, however, the other LED strings 31 are still in normal illumination. That is to say, the light source group of the present invention may slightly reduce the brightness due to the shutdown of some problematic light-emitting diode strings. However, it can effectively avoid the risk of failure of the entire light source group due to damage to the drive wafer. 11 200839709 In summary, in the light source group provided by the present invention, a feedback circuit is added to each LED string. When the light-emitting diode in a string of LEDs is damaged, causing an additional V-shape to drive the wafer, the feedback circuit will give the driver a comparison signal to turn the driver wafer off. The wiring state of the LED string. Thereby, the situation in which the driving wafer is overheated and damaged is avoided to ensure the normal operation of the driving wafer. In a continuous application, the light source group of the present invention can be applied not only to a backlight module with a side entrance light but also to a direct backlight module. In an embodiment, the backlight of the direct type backlight module can be formed by a plurality of light source groups side by side and integrated. The present invention has been described above by way of a preferred embodiment, and is not intended to limit the spirit of the invention and the inventive subject matter. For those skilled in the art, other components or means can be easily understood and utilized to produce the same effect. Modifications made within the spirit and scope of the invention are intended to be included within the scope of the appended claims. ® [Simple Description of the Drawings] The above and other advantages of the invention can be easily understood by the following detailed description in conjunction with the accompanying drawings, in which: Fig. 1 is a fiction, vehicle, transduction Schematic diagram of the difference; Figure 1 is a circuit diagram of a conventional light source group; and " Figure 2 is a schematic circuit diagram of the light source group of the present invention. [Main component symbol description] · 200839709 Light source group i Substrate 10 - Light-emitting diode strings 11, 21, 31 v Light-emitting diodes 1, 211, 311 Light guide plate 50 Light-emitting surface 51 Side end 52 Driving wafers 22, 32 Switching elements 33 • First end 331 Second end 332 Third end 333 Comparator 34 First input 341 Second input 342 Input voltage Vin Output voltage Vref 13