M413298 五、新型說明： 【新型所屬之技術領域】 本創作是有關於一種發光二極體電路，且特別是有關於一種發光二極 體媒動電路。 【先前技術】 請參考第1圖，第1圖是習知之發光二極體驅動電路的電路圖。第i 圖中，發光二極體驅動電路包括一電晶體回授保護電路1〇〇、一發光二極體 •負載110、一脈波寬度調變電路120、一過壓控制電路130及一低壓控制電 路 140 〇 具體而、言，電晶體回授保護電路1〇〇通常是利用一個pNp雙載子接面 電晶體來實現；其係用以取樣通過發光二極體負載11〇的工作電流大小， 進而驅動過壓控制電路130及低壓控制電路14〇。藉此，過壓控制電路13〇 及低壓控制電路140復能進一步控制脈波寬度調變電路12〇，進而達到調節 發光二極體負載110之電流的目的。 瞻 然而，習知的電晶體回授保護電路100至少有兩個缺陷。第一是因為 其係利用PNP雙載子接面電晶體來實現之，故須工作在口仲雙載子接面電 晶體的線性區。所以，電晶體回授保護電路1〇〇天生容易受環境溫度影響 而飄移。溫度-但飄移’則會使誤差變大，甚至無法達到保護發光二極體 負載110的初始設計目的H以PNP雙載子接面電晶體來實現的電晶 體回授保4電路1GG ’對於低電壓之偵測功能十分有限，尤其是其流控的本 質，可謂幾乎沒辦法偵測到發光二極體負載11〇低電壓的狀況。 【新型内容】 3 M413298 因此，本創作之一目的是在提供一種發光二極體驅動保護裝置，其係 可提高過電壓偵測的準確度，並同時增加低電壓偵測的功能，以解決習知 之電晶體回授保護電路對於低電壓幾乎沒辦法偵測的缺陷。 根據本創作之一實施方式，提出一種發光二極體驅動保護裝置，係用 以驅動一發光二極體負載。發光二極體驅動保護裝置包括一發光二極體驅 動電路及一回授保護電路，回授保護電路係根據發光二極體負載的工作電 壓，回授控制發光二極體驅動電路。發光二極體驅動電路包括一脈波寬度 調變電路、一過壓控制電路及一低壓控制電路。脈波寬度調變電路係用以 控制發光二極體負載的工作電流大小；過壓控制電路係用以於發光二極體 負載的工作電壓高於一上限值時，控制脈波寬度調變電路，以減低發光二 極體負載的工作電流；低壓控制電路係用以於發光二極體負載的工作電壓 低於一下限值時，控制脈波寬度調變電路，以增加發光二極體負載的工作 電流。回授保護電路包括一取樣電路及一電流鏡電路。取樣電路係用以取 樣發光二極體負載的工作電壓大小，進而產生一取樣電流；電流鏡電路係 用以根據取樣電流，產生一控制電壓以驅動發光二極體驅動電路。 本創作之另一目的是在提供一種回授保護電路，以克服習知之電晶體 回授保護電路易受溫度飄移的缺陷。 根據本創作之另一實施方式，提出一種回授保護電路，其係用以控制 一發光二極體驅動電路；發光二極體驅動電路則係用以驅動一發光二極體 負載。回授保護電路包括一取樣電路及一電流鏡電路。取樣電路係用以取 樣發光二極體負載的工作電壓大小，進而產生一取樣電流；電流鏡電路係 用以根據取樣電流’產生一控制電壓以驅動發光二極體驅動電路。值得注 M413298 i 意的是’電流鏡電路使發光二極體駆動電路與發光二極體負載形成非共地 結構。 種回授保護電路，以提升對低電壓债測 本創作之又一目的是在提供— 的靈敏度® 本創作之再目的疋在提供—種發光二極體驅動保護裝置以提升對 過電壓偵測的準禮度。 根據本創作之再Λ〜方式’提出—種發光二極體驅祕護裝置豆 包括-發光二極體驅動電路；發光二極體驅動電路係用以驅動—發光二極 體負載。特徵在於發光二極體驅動保護裝置更包括-取樣電路及一電流鏡 電路。取樣電路伽以取樣贱二極體貞載駐作電壓大小，進而產生一 取樣電流；電流鏡電路侧以根據取魏流，產生—㈣龍以驅動發光 -極體驅動電路。值得—提的是，電流鏡電路使發光二極體驅動電路與發 光一極體負載形成非共地結構。 具體而言，在本創作其他實施方射，上述諸實施方射的取樣電路 可並聯於負載，亦即發光二極體負載。另_方面，上述諸實施方式中的電 流鏡電路可利用一運算放大器來實現之。 藉此，本創作前述諸實施方式中的發光二極體驅動保護裝置及其回授 保護電路不僅克服了習知之電晶體回授保護電路易受溫度飄移及對低電壓 不靈敏的缺陷，更提升了對高電壓醉確度及整體的強健性。 【實施方式】 請參考第2圖，第2圖是本創作一 實施方式之發光二極體驅動保護裝 置的電路圖。第2圖中 發光二極體驅動保護裝置除發光二極體負載11〇、 5 M413298 脈波寬度調變電路12〇、過壓控制電路13〇及低壓控制電路14〇外更具有 一回授保護電路200。 回授保護電路200的設計理念包括基於發光二極體負載11〇本身受工 作電流控制其亮度的本質，將習知以流控元件執行的電流偵測機制，改設 U十為電壓偵測機制，以提升準確度；另一方面，回授保護電路的設計 理念更包括電路區塊間分級獨立的思維，以電流鏡結構達成非共地的發光 二極體負载110與發光二極體驅動電路，亦即脈波寬度調變電路12〇、過壓 控制電路130及低壓控制電路14〇，進而提升電路強健性。 回授保護電路200在具體設計上是利用電流鏡電路將發光二極體負載 110與發光二極體驅動電路隔離開來，使兩者非共地。另一方面，因為習知 的電晶體回授保護電路1()〇是用流控元件，亦即pNp雙載子接面電晶體來 實現，所以當電流太小時，很難使PNP雙載子接面電晶體正常工作， 更遑論使其工作在線錄好眺倾。鼠，本實财式將傳統的電流取 樣方式更改為電壓取樣方式，既考量了發光二極體負載ιι〇的特性，也解 決了習知的電晶體回授保護電路100隨溫度飄移又對低電壓不靈敏的缺陷。 因此’在電路貫現上，以第2圖為例’回授保護電路包括取樣電 路210及電晶體電路220。舉例來說，取樣電路21〇並聯於發光二極體負載 110 ’而電晶體電路220則可_運算放大器内部的電流鏡來實現。第2圖 中’取樣電路210所取樣的電壓Vrs為發光二極體負載ιι〇之工作電壓心 的分壓，具體計算如下：M413298 V. New description: [New technical field] This creation is related to a light-emitting diode circuit, and in particular to a light-emitting diode dielectric circuit. [Prior Art] Please refer to Fig. 1, which is a circuit diagram of a conventional LED driving circuit. In the first embodiment, the LED driving circuit includes a transistor feedback protection circuit 1 , a light emitting diode load 110 , a pulse width modulation circuit 120 , an over voltage control circuit 130 , and a Low-voltage control circuit 140 〇 Specifically, the transistor feedback protection circuit 1 is usually implemented by using a pNp dual-carrier junction transistor; it is used to sample the operating current through the LED load 11〇 The size, in turn, drives the overvoltage control circuit 130 and the low voltage control circuit 14A. Thereby, the overvoltage control circuit 13A and the low voltage control circuit 140 can further control the pulse width modulation circuit 12A to achieve the purpose of adjusting the current of the LED load 110. However, the conventional transistor feedback protection circuit 100 has at least two drawbacks. The first is because it is implemented using a PNP bipolar junction junction transistor, so it must operate in the linear region of the inter-secondary bipolar junction transistor. Therefore, the transistor feedback protection circuit 1 is naturally susceptible to drift due to ambient temperature. Temperature-but drifting will make the error larger, even failing to achieve the initial design objective of protecting the LED load 110. The transistor back-protected 4 circuit 1GG' is implemented with a PNP bipolar junction transistor. The detection function of the voltage is very limited, especially the nature of its flow control, which means that there is almost no way to detect the low voltage of the LED load 11〇. [New Content] 3 M413298 Therefore, one of the purposes of this creation is to provide a light-emitting diode driving protection device that can improve the accuracy of over-voltage detection and simultaneously increase the function of low-voltage detection to solve the problem. Knowing that the crystal feedback protection circuit has almost no way to detect defects with low voltage. According to one embodiment of the present invention, a light-emitting diode driving protection device is provided for driving a light-emitting diode load. The LED driving protection device comprises a light emitting diode driving circuit and a feedback protection circuit, and the feedback protection circuit is controlled to control the LED driving circuit according to the working voltage of the LED load. The LED driving circuit comprises a pulse width modulation circuit, an overvoltage control circuit and a low voltage control circuit. The pulse width modulation circuit is used to control the working current of the LED load; the overvoltage control circuit is used to control the pulse width adjustment when the operating voltage of the LED load is higher than an upper limit. The circuit is changed to reduce the operating current of the LED load; the low-voltage control circuit is used to control the pulse width modulation circuit to increase the illumination when the operating voltage of the LED load is lower than the lower limit. The operating current of the pole load. The feedback protection circuit includes a sampling circuit and a current mirror circuit. The sampling circuit is configured to sample the operating voltage of the LED load to generate a sampling current; the current mirror circuit is configured to generate a control voltage to drive the LED driving circuit according to the sampling current. Another object of the present invention is to provide a feedback protection circuit that overcomes the drawbacks of conventional transistor feedback protection circuits that are susceptible to temperature drift. According to another embodiment of the present invention, a feedback protection circuit for controlling a light emitting diode driving circuit is provided, and a light emitting diode driving circuit is used for driving a light emitting diode load. The feedback protection circuit includes a sampling circuit and a current mirror circuit. The sampling circuit is configured to sample the operating voltage of the LED load to generate a sampling current; the current mirror circuit is configured to generate a control voltage according to the sampling current ' to drive the LED driving circuit. It is worth noting that M413298 i means that the current mirror circuit makes the LED dipole circuit and the LED load form a non-co-structure. Another kind of feedback protection circuit to enhance the creation of low-voltage debt test is to provide the sensitivity of the product. The purpose of this creation is to provide a light-emitting diode drive protection device to improve over-voltage detection. The standard of courtesy. According to the re-enactment of the present invention, a light-emitting diode driving device includes a light-emitting diode driving circuit, and a light-emitting diode driving circuit is used to drive the light-emitting diode load. The feature is that the LED driving protection device further comprises a sampling circuit and a current mirror circuit. The sampling circuit is tuned to sample the voltage of the diode, and then generate a sampling current; the current mirror circuit side generates a (four) dragon to drive the light-emitting body driving circuit according to the Wei flow. It is worth mentioning that the current mirror circuit forms a non-co-structure of the LED driving circuit and the light-emitting diode load. Specifically, in other embodiments of the present invention, the sampling circuits of the above-described embodiments may be connected in parallel to the load, that is, the LED load. On the other hand, the current mirror circuit in the above embodiments can be realized by an operational amplifier. Therefore, the LED driving protection device and the feedback protection circuit thereof in the foregoing embodiments of the present invention not only overcome the defects that the conventional transistor feedback protection circuit is susceptible to temperature drift and low voltage, but also improve The high voltage drunkness and overall robustness. [Embodiment] Please refer to Fig. 2, which is a circuit diagram of a light-emitting diode driving protection device according to an embodiment of the present invention. In the second figure, the LED driving protection device has a feedback function except for the LED load 11〇, 5 M413298 pulse width modulation circuit 12〇, the overvoltage control circuit 13〇 and the low voltage control circuit 14〇. Protection circuit 200. The design concept of the feedback protection circuit 200 includes the essence of controlling the brightness of the light-emitting diode load 11 〇 itself by the working current, and the current detection mechanism implemented by the flow control element is changed to a voltage detection mechanism. In order to improve the accuracy; on the other hand, the design concept of the feedback protection circuit further includes the grading and independent thinking between the circuit blocks, and the non-common light-emitting diode load 110 and the light-emitting diode driving circuit are realized by the current mirror structure. That is, the pulse width modulation circuit 12〇, the overvoltage control circuit 130, and the low voltage control circuit 14〇, thereby improving circuit robustness. The feedback protection circuit 200 is specifically designed to isolate the LED load 110 from the LED driver circuit by means of a current mirror circuit so that the two are non-common. On the other hand, since the conventional transistor feedback protection circuit 1() is implemented by a flow control element, that is, a pNp bipolar junction transistor, when the current is too small, it is difficult to make the PNP double carrier. The junction transistor works normally, let alone make it work online. The mouse, the real money type changes the traditional current sampling mode to the voltage sampling mode, which not only considers the characteristics of the light-emitting diode load ιι〇, but also solves the conventional transistor feedback protection circuit 100 with temperature drifting and low A voltage insensitive defect. Therefore, the feedback protection circuit includes a sampling circuit 210 and a transistor circuit 220 in the circuit diagram. For example, the sampling circuit 21 is connected in parallel to the LED load 110' and the transistor circuit 220 can be implemented as a current mirror inside the operational amplifier. In Fig. 2, the voltage Vrs sampled by the sampling circuit 210 is the partial voltage of the working voltage center of the light-emitting diode load ιι〇, and the specific calculation is as follows:
Irs=Vled/(Rl +RS+R2)Irs=Vled/(Rl +RS+R2)
Vrs=Irs*RS M413298 接下來’對電晶體電路220而言，取樣電流i=Vrs/RG，則控制電壓 Vrl-i*RL。藉此，控制電壓vri便可進一步驅動過壓控制電路go及低壓 控制電路140。過壓控制電路13〇及低壓控制電路14〇依其電路設計與阻抗 匹配，設有上限值與下限值來間接對應發光二極體負載11〇的工作電壓 Vied，當工作電壓Vied高於上限值時’則過壓控制電路13〇控制脈波寬度 調變電路120，將電晶體qi的開啟脈寬調低，以減低發光二極體負載 的工作電流，同理，當工作電壓vled低於下限值時，則低壓控制電路 •控制脈波寬度調變電路120，將電晶體Q1的開啟脈寬調高，以增加發光二 極體負載110的工作電流。 因此，藉由回授保護電路200的上述諸般特徵，本實施方式之發光二 極體驅動保護裝置可以實現電性分級隔離與精準的電壓回授機制，進而克 服習知之電晶體回授保護電路100的諸多缺陷。 雖然本創作已以諸實施方式揭露如上，然其並非用以限定本創作，任 何熟習此技藝者，在不脫離本創作之精神和範圍内，當可作各種之更動與 _潤飾’因此本創作之保護範圍當視後附之申請專利範圍所界定者為準。 '【圖式簡單說明】 為讓本揭不内容之上述和其他目的、特徵、優點與實施例能更明顯易懂， 所附圖式之說明如下： 第1圖是習知之發光二極體驅動電路的電路示意圖。 第2圖是本鑛-實施方式之發光二極體驅動保護裝置喊路示意圖。 【主要元件符號說明】 100 電晶體回授保護電路 7 M413298 110 發光二極體負載 120 脈波寬度調變電路 130 過壓控制電路 140 低壓控制電路 200 回授保護電路 210 取樣電路 220 電流鏡電路Vrs = Irs * RS M413298 Next, for the transistor circuit 220, the sampling current i = Vrs / RG, the control voltage Vrl - i * RL. Thereby, the control voltage vri can further drive the overvoltage control circuit go and the low voltage control circuit 140. The overvoltage control circuit 13〇 and the low voltage control circuit 14 are matched with the impedance according to their circuit design, and have an upper limit value and a lower limit value to indirectly correspond to the operating voltage Vied of the light emitting diode load 11〇, when the operating voltage Vied is higher than At the upper limit value, the overvoltage control circuit 13 controls the pulse width modulation circuit 120 to lower the turn-on pulse width of the transistor qi to reduce the operating current of the light-emitting diode load. Similarly, when the operating voltage is When vled is lower than the lower limit value, the low voltage control circuit controls the pulse width modulation circuit 120 to increase the opening pulse width of the transistor Q1 to increase the operating current of the light emitting diode load 110. Therefore, by the above-mentioned features of the feedback protection circuit 200, the LED driving protection device of the present embodiment can realize electrical hierarchical isolation and accurate voltage feedback mechanism, thereby overcoming the conventional transistor feedback protection circuit 100. Many defects. Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and anyone skilled in the art can make various changes and refinements without departing from the spirit and scope of the present invention. The scope of protection is subject to the definition of the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The above and other objects, features, advantages and embodiments of the present invention will be more apparent and understood. The description of the drawings is as follows: Figure 1 is a conventional light-emitting diode drive. Circuit diagram of the circuit. Fig. 2 is a schematic diagram of the shouting of the light-emitting diode driving protection device of the present mine-implementation mode. [Main component symbol description] 100 Transistor feedback protection circuit 7 M413298 110 LED load 120 Pulse width modulation circuit 130 Overvoltage control circuit 140 Low voltage control circuit 200 Feedback protection circuit 210 Sampling circuit 220 Current mirror circuit