200938007 九、發明說明： 【發明所屬之技術領域】 本發明係有關短路保護電路技術，特別是關於一種發光二極體 列之短路保護電路及其方法。 串 【先前技術】 由於LED技術的進步’ LED應用亦日漸多元化，以led作為顯 示器的背光源、照明設備等，更是近來熱門的話題，主要是不同種類 的LED背光源技術分別在色彩、亮度、壽命、耗電度及環保訴求等约 比傳統冷陰極管（CCFL)更具優勢’因而應用日漸廣泛。 二 以發光二極體作為顯示面板之背光源為例，主要係包含有複數條 發光二極體串列，每一發光二極體串列係由複數個發光二極體組成' 並利用一控制積體電路（Control 1C)來控制該等發光二極體串列之作 動，以有效作為顯示面板之背光源。然而，由於發光二極體皆是以串 列方式存在，當串列中有其中一發光二極體損毀而發生短路時，即會 造成高電流、高電壓降聚集在控制積體電路上，而造成整個串列燒毀。 由於現有技術無法偵測有單一顆發光二極體短路的電壓，因此， 現有作法係在控制積體電路中設定一固定電壓，一旦偵測到的電壓大 ❹於此固定電壓時大於此固定電壓時，會將其關機（Sh〇utdown)，以保 護發光二極體串列；然因發光二極體之順向電壓（Vf)範圍大，自2 8V 〜3.6V，使得保護之固定電壓點難以決定，若設定太高，容易發生偵 測不到的問題，若設定太低則易發生誤判的問題；再者，由於發光二 極體之順向電壓易受溫度影響而飄動，進而導致誤判，此現象亦會使 發光二極體在正常運作下被關機。 有鑑於此，本發明遂提出一種發光二極體串列之短路保護電路及 其方法，以改善存在於先前技術中之該些問題點。 【發明内容】 本發明之主要目的係在提供一種發光二極體串列之短路保護電路 5 200938007 ^其^法，其係利用發光二極體串列中的至少一發光二極趙之回授作 為保護電壓之調整基準，以動_整保護職之順向基準電應，避免 誤判之情事發生。 本發批另-目的係錢供—種發光二紐_狀祕保護電路 、方法，其係可在發光二極體發生短路時，立即反應而關避免 造成電路燒毁。 Ο200938007 IX. Description of the Invention: [Technical Field] The present invention relates to a short circuit protection circuit technology, and more particularly to a short circuit protection circuit for a light emitting diode and a method thereof. String [Prior Art] Due to the advancement of LED technology' LED applications are increasingly diversified, with LED as the backlight of the display, lighting equipment, etc., is a hot topic recently, mainly different types of LED backlight technology in color, Brightness, longevity, power consumption, and environmental appeal are more advantageous than traditional cold cathode tubes (CCFLs). Taking the light-emitting diode as the backlight of the display panel as an example, the main system includes a plurality of light-emitting diodes, and each of the light-emitting diodes is composed of a plurality of light-emitting diodes. The integrated circuit (Control 1C) controls the operation of the LED arrays to effectively serve as a backlight for the display panel. However, since the light-emitting diodes are present in a series manner, when one of the series of light-emitting diodes is damaged and a short circuit occurs, high current and high voltage drop are concentrated on the control integrated circuit. Caused the entire series to burn out. Since the prior art cannot detect the voltage of a single LED short circuit, the existing method sets a fixed voltage in the control integrated circuit, and the detected voltage is greater than the fixed voltage when the detected voltage is greater than the fixed voltage. When it is turned off (Sh〇utdown) to protect the LED series; however, because the forward voltage (Vf) range of the LED is large, from 28 V to 3.6 V, so that the fixed voltage point of protection It is difficult to decide. If the setting is too high, it is easy to cause undetectable problems. If the setting is too low, the problem of misjudgment is easy to occur. Furthermore, since the forward voltage of the light-emitting diode is easily affected by temperature, it causes misjudgment. This phenomenon also causes the light-emitting diode to be turned off under normal operation. In view of the above, the present invention proposes a short circuit protection circuit for a light emitting diode series and a method thereof to improve the problems existing in the prior art. SUMMARY OF THE INVENTION The main object of the present invention is to provide a short circuit protection circuit for a light-emitting diode series 5 200938007, which utilizes at least one of the light-emitting diodes in the series of light-emitting diodes. As a basis for the adjustment of the protection voltage, the forward reference should be used to prevent the occurrence of misjudgment. The other part of the present invention is for the purpose of protecting the circuit and method, and the method can be used to prevent the circuit from burning when the short circuit of the light-emitting diode is short-circuited. Ο
輯本發日月’係提出-種發光二贿串列之短路保護電路，包括 ^至少-發光二極趙串列或是複數發光二極趙串列，每—串列係由複 數個發光二極想組成控解元係_並提供每—發光二極禮串列 ^所需之工作電屋；以及—短路保護單元，其係電性連接至每一發光 極體串列之發光—極體二端，以得到該發光二極體之—量測電壓， 並根據此量測電壓與-順向基準電壓之大小，鑛是否發生短路。詳 舌之’若此量測雜上升’並超職順向基準電壓時，即表示對應之 該串發光二極體串列中之其中之—發生短路，此時，旋即使此發光二 極體串列開路，以有效避免燒毀整個電路。 再者’本發明亦提出一種發光二極艘串列之短路保護方法，首先， 驅動至少-發光二極體串列作動發光，且發光二極體串舰包含複數 發光二極體；再持續細此發光二極體串列中的其中之—發光二極體 的電麗’以得到-量測電壓；並判斷此量測電壓是否大於—順向基準 電壓若是，則使此發光二極體串列開路，若否，則重複回到偵測量 測電壓之步驟。 當然，上述所使用之順向基準電壓可依發光二極髏溫度上升或下 降來動態調整更新，以提高判斷準確性，並有效避免誤判斷發生。 底下藉由具體實施例配合所附的圖式詳加說明，當更容易瞭解本 發明之目的、技術内容、特點及其所達成之功效。 【實施方式】 本發明提出之發光二極體串列（Ledlightbar)之短路保護電路及 6 200938007 其方法’其係利用發光二極艘串列中的至少—發光二極艘之回授作為 保護電壓之調整基準，如此即可依據顯示面板選㈣發光二極艘之順 向電壓（VF)來決定保護電壓之順向基準電壓，再者，更可依據溫度 上升或下降自動動態調整順向基準電壓。 請參閱第1圖所示，此發S二極财列之短路保護電路，係包含 有一條或數條發光二極鱧串列10、控制單元20和短路保護單元3〇三 大部分，圖中所示之數條發光二極體串列1〇係作為液晶顯示面板之背 光源，每一發光二極體串列1〇係由複數個發光二極體1〇2串接而成； 控元20 接至該些發光二極體iq，帛以驅動並提供發光二 ©極體串列10所需之工作電壓；以及短路保護單元3〇之二熬接點係連 接至每-發光二極體串列10之發光二極體1〇4之二端，且短路保護 單元30係内設有一順向基準電壓，且此順向基準電壓係每隔一段時間 即進行更新（refresh)動作，以根據耦接點之量測電壓與順向基準電 麼來判斷疋否有任何發光二極體串列1〇發生短路情況；當量測電壓上 升，並超過順向基準電壓時，即表示該等發光二極體之其中之一發生 短路，旋即打開其所屬之發光二極體串列10 ^其中，上述之控制單元 20及短路保護單元30係可整合至同一發光二極體積體電路中。 請參閱第2圖，同時配合第1圖所示’控制單元係可使用-脈波 寬度調變（PWM)單元202，以提供足夠電位給發光二極體串列。在 短路保護單元30中更包括有一記錄電位單元3〇2，其係連接至發光二 極體104二端之耦接點，且為所有發光二極體串列1〇所共用，用以 記錄前述之順向基準電壓VF ’並依耦接點D1〜Dn之量測電麼vD來 做為判斷短路之參考點電壓。 接續以第2圖為例，配合第3圖之流程圖來詳細說明本發明之短 路保護方法，如圖所示，首先如步驟S10所示，在系統初職時，驅 動發光二極體串列10發光，此時記錄電位單元302立即記錄順向基 準電壓VD後，即可切斷記錄電位單元與發光二極體之連線。初開機時 200938007 之詳細作動原理為（以Ch1為例）：輸入至短路保護單元3〇之致能 (enable)訊號EN為1，此時電晶體qi為on，chi=〇，使得電晶 體Q1保持為ON。 接續步驟S12所示，短路保護單元30持續偵測發光二極體串列 1〇中之發光二極體104的量測電壓vD ;此時為開機後系統穩定時， 其詳細作動原理為（以〇h1為例）：輸入之致能訊號為〇(EN=〇)，此 時電壓V-大於電壓v+，電壓V1=0，Ch1=0，使得電晶體⑴為on， 持續供電給發光二極體串列1〇。 最後如步驟S14所示，判斷量測電壓Vd是否大於該順向基準電 ©壓VF ’若否’則回到上一步驟S12，若是，表示量測電壓ν〇超過順 向基準電壓VF，代表有其中一個發光二極體發生短路了，此時即進行 步驟S16，使該發光二極體串列1〇開路。此時為發光二極體發生短 路，其詳細作動原理為（以Chl為例）：輸入之致能訊號為〇，此時量 測電壓Vd1上升，電壓V+大於電壓v_，電壓Vl=Hh Ch1=Hh使得 電晶體Q1為OFF，使發光二極體串列Ch1開路（〇pen)。 其中，為使組成發光二極體串列之發光二極體具有極為接近之順 向基準電壓Vf，同一液晶顯示面板係可選用同一批次（Bin)之發光 鵪二極體(現有方式即採用此法），使其順向基準電sVf相差在大約〇 w 之，。再者，前面所舉之實施例，在短路保護單元中係以-個記錄電 位單元給各發光二極體㈣糾，除此之外，此短職護單元更包括 複數記錄電位單元，使每-發光二極體串列之输點分別連接有一個 記錄電位單元，分別用以記錄各自串列的順向基準電壓。 再者，由於發光二極體之順向電壓易受溫度影響而飄動，因此上 述之順向基準電壓係每隔-段時間即進行更新（refresh)動作，以達 到準確判斷，避免誤判之情況發生。 因此，本發明係利用發光二極鳢串列中的至少一發光二極體之回 授作為保護f壓之調整基準，可有效避免_之情事發生，且在在發 8 200938007 光二極體發生短路時，立即反應而關機，避免造成電路燒毀。 以上所述之實施例僅係為說明本發明之技術思想及特點，其目的 在使熟習此項技藝之人士能夠瞭解本發明之内容並據以實施，當不能 以之限定本發明之專利範圍，即大凡依本發明所揭示之精神所作之均 等變化或修飾，仍應涵蓋在本發明之專利範圍内。 【圖式簡單說明】 第1圖為本發明之短路保護電路的方塊示意圖。 第2圖為本發明之短路保護電路的具體電路示意圖。 第3圖為本發明之短路保護方法之流程圖。 © 【主要元件符號說明】 10發光二極體串列 102發光二極體 104發光二極體 20控制單元 202脈波寬度調變單元 30短路保護單元 302記錄電位單元The series of short-term protection circuits, including the at least-lighting dipole Zhao series or the complex luminous dipole Zhao series, each string is composed of a plurality of light-emitting diodes. I want to form a control system _ and provide a working electric house for each light-emitting diode string; and a short-circuit protection unit that is electrically connected to the illuminating body of each illuminating body string. The two ends are used to obtain the measured voltage of the light-emitting diode, and according to the measured voltage and the forward reference voltage, whether the mine is short-circuited. If the reference 'if this amount is increased,' and the over-the-go forward reference voltage, it means that one of the series of LEDs in the string is short-circuited. At this time, even the light-emitting diode is rotated. Serial open circuit to effectively avoid burning the entire circuit. Furthermore, the present invention also proposes a short-circuit protection method for a series of light-emitting diodes. First, the at least-light-emitting diodes are driven in series, and the light-emitting diodes comprise a plurality of light-emitting diodes; The light-emitting diode of the light-emitting diode is obtained by measuring the voltage of the light-emitting diode; and determining whether the measured voltage is greater than - the forward reference voltage is such that the light-emitting diode string is Open the column, if not, repeat the step back to the detection voltage. Of course, the forward reference voltage used above can be dynamically adjusted and updated according to the rising or falling of the temperature of the LED, so as to improve the accuracy of the judgment and effectively avoid the occurrence of misjudgment. The purpose, technical contents, features, and effects achieved by the present invention will become more apparent from the detailed description of the embodiments and the accompanying drawings. [Embodiment] The short circuit protection circuit of the LED light emitting diode (Ledlightbar) proposed by the present invention and 6 200938007, the method thereof uses the feedback of at least the light-emitting diode in the series of light-emitting diodes as the protection voltage Adjusting the reference, so that the forward voltage of the protection voltage can be determined according to the forward voltage (VF) of the light-emitting diode of the display panel, and the forward reference voltage can be automatically dynamically adjusted according to the temperature rise or fall. . Please refer to FIG. 1 , the short circuit protection circuit of the S pole and the second pole, including one or several light emitting diodes, the control unit 20 and the short circuit protection unit 3, in the figure, The plurality of light-emitting diodes are arranged as a backlight of the liquid crystal display panel, and each of the light-emitting diodes is connected in series by a plurality of light-emitting diodes 1〇2; 20 is connected to the light-emitting diodes iq to drive and provide the operating voltage required for the light-emitting diode series 10; and the short-circuit protection unit 3 is connected to each of the light-emitting diodes The two ends of the light-emitting diodes 1〇4 of the series 10, and the short-circuit protection unit 30 is provided with a forward reference voltage, and the forward reference voltage is refreshed at intervals to be The measurement voltage of the coupling point and the forward reference voltage determine whether there is any short circuit of the LED series 1〇; when the equivalent voltage rises and exceeds the forward reference voltage, it indicates the illumination A short circuit occurs in one of the diodes, and immediately turns on the light-emitting diode to which it belongs. Tandem 10 ^ wherein the control unit 20 and the short circuit protection unit 30 may be integrated into the same based light-emitting diode circuits in volume. Referring to Figure 2, in conjunction with Figure 1, the control unit can use a pulse width modulation (PWM) unit 202 to provide sufficient potential for the LED array. The short circuit protection unit 30 further includes a recording potential unit 3〇2 connected to the coupling point of the two ends of the light emitting diode 104, and shared by all the LED series 1〇 for recording the foregoing The forward reference voltage VF′ is measured by the amount of the coupling points D1 to Dn, and the vD is used as a reference point voltage for judging the short circuit. Referring to FIG. 2 as an example, the short circuit protection method of the present invention will be described in detail in conjunction with the flowchart of FIG. 3. As shown in the figure, first, as shown in step S10, the LED array is driven in the initial stage of the system. When the recording potential unit 302 immediately records the forward reference voltage VD, the connection between the recording potential unit and the light-emitting diode can be cut off. The detailed operation principle of 200938007 at the initial startup is (taking Ch1 as an example): the enable signal EN input to the short-circuit protection unit 3 is 1, and the transistor qi is on, chi=〇, so that the transistor Q1 Keep it ON. In the subsequent step S12, the short-circuit protection unit 30 continuously detects the measurement voltage vD of the light-emitting diode 104 in the LED array 1; at this time, when the system is stable after power-on, the detailed operation principle is 〇h1 is an example): The input enable signal is 〇(EN=〇). At this time, the voltage V- is greater than the voltage v+, the voltage V1=0, and the Ch1=0, so that the transistor (1) is on, and the power supply is continuously supplied to the light-emitting diode. The body string is 1〇. Finally, as shown in step S14, it is determined whether the measurement voltage Vd is greater than the forward reference voltage VF 'if no' to return to the previous step S12, and if so, the measurement voltage ν 〇 exceeds the forward reference voltage VF, representing If one of the light-emitting diodes is short-circuited, step S16 is performed to open the light-emitting diodes in series. At this time, the light-emitting diode is short-circuited, and the detailed operation principle is (taking Chl as an example): the input signal is 〇, at which time the measurement voltage Vd1 rises, the voltage V+ is greater than the voltage v_, and the voltage Vl=Hh Ch1= Hh turns the transistor Q1 OFF, causing the light-emitting diode string Ch1 to open. In order to make the light-emitting diodes constituting the light-emitting diode series have a very close forward reference voltage Vf, the same liquid crystal display panel can use the same batch (Bin) light-emitting diode (the existing method is adopted) This method) is such that the forward reference electric sVf differs by approximately 〇w. Furthermore, in the above-mentioned embodiment, in the short-circuit protection unit, each of the light-emitting diodes (four) is corrected by a recording potential unit, and in addition, the short-working unit further includes a plurality of recording potential units, so that each - The input points of the LED array are respectively connected with a recording potential unit for respectively recording the forward reference voltages of the respective series. Furthermore, since the forward voltage of the light-emitting diode is easily affected by the temperature, the forward reference voltage is refreshed every other time to achieve accurate judgment and avoid misjudgment. . Therefore, the present invention utilizes feedback of at least one of the light-emitting diodes as a reference for adjusting the f-voltage, which can effectively avoid the occurrence of the situation, and is short-circuited in the light source of the 200938007 light-emitting diode. When it is immediately reacted and shut down to avoid causing the circuit to burn out. The embodiments described above are merely illustrative of the technical spirit and the features of the present invention, and the objects of the present invention can be understood by those skilled in the art, and the scope of the present invention cannot be limited thereto. That is, the equivalent variations or modifications made by the spirit of the present invention should still be included in the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing the short circuit protection circuit of the present invention. FIG. 2 is a schematic diagram of a specific circuit of the short circuit protection circuit of the present invention. Figure 3 is a flow chart of the short circuit protection method of the present invention. © [Main component symbol description] 10 light-emitting diode series 102 light-emitting diode 104 light-emitting diode 20 control unit 202 pulse width modulation unit 30 short-circuit protection unit 302 recording potential unit
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