201228476 六、發明說明： 【發明所屬之技術領域】 本揭示内容是有關於一種電路結構及其運作方法，且 特別是有關於一種具有發光二極體驅動電路之發光二極體 電路及其運作方法。 【先前技術】 發光二極體（light emitting diode ; LED)與傳統的燈 泡照明工具相較下，估計效率約為傳統燈泡的四倍。並且， 發光二極體並沒有傳統的燈泡含有有毒的水銀，更擁有較 燈泡更長的使用壽命。種種因素下，發光二極體已經成為 現代照明科技最新的主流技術。 電流汲取電路常應用於發光二極體電路中的發光二極 體串中，以提供一個穩流穩壓的機制。當與發光二極體串 其中之一的輸出端電壓相關的迴授電壓被用來與一個固定 的參考電壓做比較，以達到迴授控制的機制時，這個輸出 端電壓的電壓值常因而被維持在參考電壓的大小附近。當 發光二極體串的運作模式改變而使發光二極體串的電流變 小時，電流汲取電路所產生的熱卻由於固定的參考電壓的 存在，而不會因為電流變小而下降，因此將在小電流運作 模式下造成額外的功率損耗。 因此，如何設計一個具有發光二極體驅動電路之發光 二極體電路及其運作方法，以克服上述的問題，乃為此一 業界亟待解決的問題。 201228476 【發明内容】 因此，本揭示内容之一態樣是在提供一種發光二極體 (light emitting diode ; LED)驅動電路，用以驅動複數個 發光二極體串（channel)，該發光二極體驅動電路包含：複 數個電流汲取模組、電流鏡以及直流至直流轉換器。電流 汲取模組分別連接至發光二極體串其中之一以及輸出負 載，以將輸出負載之電壓栓鎖於設定電壓準位。電流鏡包 含：輸入分支以及輸出分支。輸入分支根據可變設定負載 ^ 產生輸入設定電流。輸出分支產生輸出設定電流’輸出分 支包含相串聯之第一負載以及第二負載，以分別根據輸出 設定電流產生可變參考電壓以及設定電壓。直流至直流轉 換器包含控制模組以及連接於發光二極體串之功率放大 器，其中控制模組用以根據可變參考電壓以及自發光二極 體串之複數個輸出端其中之一之迴授電壓產生驅動電壓， 以控制功率放大器之閘極，以進一步控制發光二極體串之 運作。 φ 依據本揭示内容一實施例，當可變設定負載之阻值改 變以使輸入設定電流改變，進一步使輸出設定電流根據輸 入設定電流改變時，可變參考電壓產生變動。 依據本揭示内容另一實施例，各電流汲取模組包含： 開關金氧半電晶體以及運算放大器。開關金氧半電晶體連 接於發光二極體串其中之一以及輸出負載。運算放大器包 含：正輸入端、負輸入端以及輸出端。正輸入端接收設定 電壓。負輸入端連接至輸出負載以及開關金氧半電晶體， 以將輸出負載之電壓栓鎖於設定電壓準位。輸出端連接至 201228476 開關金氧半電晶體之閘極。 依據本揭示内容又一實施例，輸出設定電流以及各發 光二極體電流串之發光二極體電流間之電流比值，與第二 負載以及輸出負載間之電阻比值相同。 依據本揭示内容再一實施例，其中第一負載為電阻或 二極體。 依據本揭示内容更具有之一實施例，其中直流至直流 轉換器更包含：電感、二極體以及電容。電感使供應電壓 • 耦合至第一端。二極體連接於第一端以及發光二極體串 間。電容連接於發光二極體串，其中功率放大器實質上連 接於第一端以根據驅動電壓對電容進行充放電。二極體之 陽極端（anode)連接至第一端，二極體之陰極端（cathode) 連接至電容。 本揭示内容之另一態樣是在提供一種發光二極體電 路，包含：複數個發光二極體串以及發光二極體驅動電路。 發光二極體驅動電路包含：複數個電流汲取模組、電流鏡 • 以及直流至直流轉換器。電流汲取模組分別連接至發光二 極體串其中之一以及輸出負載，以將輸出負載之電壓栓鎖 於設定電壓準位。電流鏡包含：輸入分支以及輸出分支。 輸入分支根據可變設定負載產生輸入設定電流。輸出分支 產生輸出設定電流，輸出分支包含相串聯之第一負載以及 第二負載，以分別根據輸出設定電流產生可變參考電壓以 及設定電壓。直流至直流轉換器包含控制模組以及連接於 發光二極體串之功率放大器，其中控制模組用以根據可變 參考電壓以及自發光二極體串之複數個輸出端其中之一之 201228476 迴授電壓產生驅動電壓，以控制功率放大器之閘極，以進 一步控制發光一極體串之運作。 依據本揭示内容一實施例，當可變設定負载之阻值改 變以使輸入设定電流改變，進一步使輸出設定電流根據輸 入設定電流改變時，可變參考電壓產生變動。 依據本揭示内容另一實施例，各電流汲取模組包含： 開關金氧半電晶體以及運算放大器。開關金氧半電晶體連 接於發光二極體串其中之一以及輸出負載其中之一。運算 # 放大器包含：正輸入端、負輸入端以及輸出端。正輸入端 接收設定電壓。負輸入端連接至輸出負載以及開關金氧半 電晶體，以將輸出負載之電壓栓鎖於設定電壓準位。輸出 端連接至開關金氧半電晶體之閘極。 依據本揭示内容又一實施例，輸出設定電流以及各發 光二極體電流串之發光二極體電流間之電流比值，與第二 負載以及輸出負載間之電阻比值相同。 依據本揭示内容再一實施例，其中第一負載為電阻或 • 二極體。 依據本揭示内容更具有之一實施例，其中直流至直流 轉換器更包含：電感、二極體以及電容。電感使供應電壓 輕合至第一端。二極體連接於第一端以及發光二極體串 間。電容連接於發光二極體串，其中功率放大器實質上連 接於第一端以根據驅動電壓對電容進行充放電。二極體之 陽極端（anode)連接至第一端，二極體之陰極端（cathode) 連接至電容。 本揭示内容之再一態樣是在提供一種發光二極體電路 201228476 運作方法，應用於發光二極體電路中，發光一極體電路包 含複數發光二極體串，發光二極體電路運作方法包含下列 步驟。根據可變設定負載於電流鏡之輸入分支產生輸入設 定電流；根據輸入設定電流於電流鏡之輸出分支產生輸出 設定電流，其中輸出分支包含相串聯之第一負載以及第二201228476 VI. Description of the Invention: [Technical Field] The present disclosure relates to a circuit structure and a method for operating the same, and more particularly to a light-emitting diode circuit having a light-emitting diode driving circuit and an operating method thereof . [Prior Art] Light emitting diodes (LEDs) are estimated to be four times more efficient than conventional bulbs compared to conventional bulb lighting tools. Moreover, the light-emitting diode does not have a conventional light bulb containing toxic mercury, and has a longer service life than the light bulb. Under various factors, the light-emitting diode has become the latest mainstream technology of modern lighting technology. The current sink circuit is often used in a light-emitting diode string in a light-emitting diode circuit to provide a stable current regulation mechanism. When the feedback voltage associated with the output voltage of one of the LED strings is used to compare with a fixed reference voltage to achieve the feedback control mechanism, the voltage of the output voltage is often Maintained near the size of the reference voltage. When the operation mode of the LED string is changed and the current of the LED string is reduced, the heat generated by the current extraction circuit is not due to the presence of a fixed reference voltage, and the current does not decrease due to the current becoming smaller. In the low current mode of operation, it causes additional power loss. Therefore, how to design a light-emitting diode circuit having a light-emitting diode driving circuit and a method for operating the same to overcome the above problems is an urgent problem to be solved in the industry. 201228476 SUMMARY OF THE INVENTION Accordingly, one aspect of the present disclosure is to provide a light emitting diode (LED) driving circuit for driving a plurality of light emitting diodes, the light emitting diode The body drive circuit includes: a plurality of current capture modules, a current mirror, and a DC to DC converter. The current capture module is respectively connected to one of the LED strings and the output load to latch the voltage of the output load to the set voltage level. The current mirror contains: the input branch and the output branch. The input branch generates an input set current based on a variable set load ^. The output branch produces an output set current. The output branch includes a first load in series and a second load to generate a variable reference voltage and a set voltage based on the output set current, respectively. The DC-to-DC converter includes a control module and a power amplifier connected to the LED string, wherein the control module is configured to feed back according to the variable reference voltage and one of the plurality of outputs of the self-luminous diode string The voltage generates a drive voltage to control the gate of the power amplifier to further control the operation of the LED string. φ According to an embodiment of the present disclosure, the variable reference voltage varies when the resistance of the variable set load is changed to change the input set current, and further the output set current is changed according to the input set current. According to another embodiment of the present disclosure, each current extraction module includes: a switch MOS transistor and an operational amplifier. The switch MOS transistor is connected to one of the LED strings and the output load. The operational amplifier includes: a positive input, a negative input, and an output. The positive input receives the set voltage. The negative input is connected to the output load and the MOS transistor is switched to latch the voltage of the output load to a set voltage level. The output is connected to the gate of the 201228476 switch MOS transistor. According to still another embodiment of the present disclosure, the current ratio between the output current and the LED current of each of the light-emitting diode current strings is the same as the resistance ratio between the second load and the output load. According to still another embodiment of the present disclosure, the first load is a resistor or a diode. There is further an embodiment in accordance with the present disclosure, wherein the DC to DC converter further comprises: an inductor, a diode, and a capacitor. The inductor causes the supply voltage • to be coupled to the first end. The diode is connected to the first end and the string of light emitting diodes. The capacitor is connected to the LED string, wherein the power amplifier is substantially connected to the first terminal to charge and discharge the capacitor according to the driving voltage. The anode of the diode is connected to the first end, and the cathode of the diode is connected to the capacitor. Another aspect of the present disclosure is to provide a light emitting diode circuit comprising: a plurality of light emitting diode strings and a light emitting diode driving circuit. The LED driving circuit comprises: a plurality of current capturing modules, a current mirror, and a DC to DC converter. The current capture module is respectively connected to one of the LED strings and the output load to lock the voltage of the output load to a set voltage level. The current mirror contains: an input branch and an output branch. The input branch generates an input set current based on the variable set load. The output branch generates an output set current, and the output branch includes a first load connected in series and a second load to generate a variable reference voltage and a set voltage according to the output set current, respectively. The DC-to-DC converter includes a control module and a power amplifier connected to the LED string, wherein the control module is configured to return to the 201228476 according to the variable reference voltage and the plurality of outputs of the self-luminous diode string. The voltage is applied to generate a drive voltage to control the gate of the power amplifier to further control the operation of the light-emitting diode string. According to an embodiment of the present disclosure, the variable reference voltage varies when the resistance of the variable set load is changed to change the input set current, and further the output set current is changed according to the input set current. According to another embodiment of the present disclosure, each current extraction module includes: a switch MOS transistor and an operational amplifier. The switch MOS transistor is connected to one of the LED strings and one of the output loads. Operation # Amplifier contains: positive input, negative input and output. The positive input receives the set voltage. The negative input is connected to the output load and the MOS transistor is switched to latch the voltage of the output load to a set voltage level. The output is connected to the gate of the switch MOS transistor. According to still another embodiment of the present disclosure, the current ratio between the output current and the LED current of each of the light-emitting diode current strings is the same as the resistance ratio between the second load and the output load. According to still another embodiment of the present disclosure, the first load is a resistor or a diode. There is further an embodiment in accordance with the present disclosure, wherein the DC to DC converter further comprises: an inductor, a diode, and a capacitor. The inductor causes the supply voltage to be lightly coupled to the first end. The diode is connected to the first end and the string of light emitting diodes. The capacitor is connected to the LED string, wherein the power amplifier is substantially connected to the first terminal to charge and discharge the capacitor according to the driving voltage. The anode of the diode is connected to the first end, and the cathode of the diode is connected to the capacitor. A further aspect of the present disclosure is to provide a method for operating a light-emitting diode circuit 201228476, which is applied to a light-emitting diode circuit, the light-emitting one-pole circuit includes a plurality of light-emitting diode strings, and the light-emitting diode circuit operation method Contains the following steps. The input set current is generated according to the variable setting load on the input branch of the current mirror; the output set current is generated at the output branch of the current mirror according to the input set current, wherein the output branch includes the first load connected in series and the second
負載，以分別根據輸出設定電流產生可變參考電壓以及設 定電壓；將連接於發光二極體串其中之一之輸出負載之電 壓检鎖於設定電壓準位；以及由發光二極體電路之控制模 組接收可變參考電壓以及自發光二極體串之複數個輸出端 其中之一之迴授電壓，以控制功率放大器之閘極，以進一 步控制發光二極體串之運作。 依據本揭示内容另一實施例，發光二極體電路運作方 士更包含下列步驟：改變可變設定負載之阻值以使輸入設 、電改變，以及根據輸入設定電流改變輸出設定電流， 以使可變參考電壓產生變動。 依據本揭示内谷又一實施例，輸出設定電流以及各4 :極體電流串之發光二極體電流間之電流比值，與第_ 、以及輪出負載間之電阻比值相同。 電^用本揭示内容之優點絲於藉由可變設定負載I 壓:二iff，建立一個可隨運作模式改變的可變沖 制的2 ΐ至不同的運作模式時動態地調整迴授嫌 $作’達到降低功率消耗的功效，而 到上; 【實施方式】 201228476 請參照第1圖。第1圖為本揭示内容之一實施例中， 發光二極體電路1之示意圖。發光二極體電路1包含：複 數發光二極體串10以及發光二極體驅動電路。發光二極體 驅動電路包含：複數個電流汲取模組12 (於第1圖以一個 方塊繪示）、直流至直流轉換器以及電流鏡16。 ~ 直流至直流轉換器包含電感140、二極體142、電容 144、控制模組146以及功率放大器148。 電感140用以將供應電壓Vp耦合至第一端P。二極體 φ 142連接於第一端P以及發光二極體串10之間。其中，二 極體142之陽極端連接至第一端P，而二極體142之陰極 端則連接至電容144以及發光二極體串10。需注意的是， 此些發光二極體串10的所具有的串數以及各發光二極體 串中包含的發光二極體的數目於不同實施例中，可視情況 進行調整。 於一實施例中，控制模組146包含誤差放大器及波寬 調變器（未繪示），其中誤差放大器根據一個參考電壓Vr • 以及一個與此些發光二極體串10的電壓相關的迴授電壓a load to respectively generate a variable reference voltage and a set voltage according to the output set current; to lock a voltage connected to one of the output loads of the LED string to a set voltage level; and to be controlled by the LED circuit The module receives the variable reference voltage and the feedback voltage of one of the plurality of outputs of the self-luminous diode string to control the gate of the power amplifier to further control the operation of the LED string. According to another embodiment of the present disclosure, the operating diode of the LED circuit further includes the steps of: changing the resistance of the variable setting load to change the input setting, the electric power, and changing the output setting current according to the input setting current, so as to enable The variable reference voltage changes. According to still another embodiment of the present disclosure, the current ratio between the output current and the LED current of each of the 4: pole current strings is the same as the resistance ratio between the _ and the wheel load. The advantage of the present disclosure is to dynamically adjust the back-up cost by dynamically setting the load I pressure: two iff, creating a variable punchable 2 ΐ to different operating modes that can change with the operating mode. "To achieve the effect of reducing power consumption, and to get on; [Embodiment] 201228476 Please refer to Figure 1. FIG. 1 is a schematic diagram of a light-emitting diode circuit 1 in an embodiment of the present disclosure. The light emitting diode circuit 1 includes a plurality of light emitting diode strings 10 and a light emitting diode driving circuit. The LED driving circuit comprises: a plurality of current capturing modules 12 (shown in a block in FIG. 1), a DC to DC converter, and a current mirror 16. ~ The DC to DC converter includes an inductor 140, a diode 142, a capacitor 144, a control module 146, and a power amplifier 148. The inductor 140 is used to couple the supply voltage Vp to the first terminal P. The diode φ 142 is connected between the first terminal P and the light emitting diode string 10. The anode end of the diode 142 is connected to the first end P, and the cathode end of the diode 142 is connected to the capacitor 144 and the LED string 10. It should be noted that the number of strings of the light-emitting diode strings 10 and the number of light-emitting diodes included in each of the light-emitting diode strings are adjusted in different embodiments as appropriate. In one embodiment, the control module 146 includes an error amplifier and a bandwidth modulator (not shown), wherein the error amplifier is based on a reference voltage Vr and a voltage associated with the voltages of the LED strings 10. Voltage
Vfb產生一個比較結果。波寬調變器進一步根據比較結果 與一個振盪訊號產生驅動電壓Vd。當驅動電壓Vd為高態 時，功率放大器148將被導通。而當驅動電壓Vd為低態 時，功率放大器148將關閉。功率放大器148因此可以在 導通及關閉間切換，以對電容144進行充放電。電容144 的充放電過程則可使發光二極體串10據以導通或關閉。 此些電流汲取模組12分別連接於這些發光二極體串 10其中之一，以提供一穩壓或穩流機制。請同時參照第2 201228476 圖。第2圖為本揭示内容一實施例中，第j圖之電流鏡 兩個發光二極體串1〇〇、102以及兩個電流汲取模組12〇、 122之不意圖。 電流汲取模組120連接於發光二極體串1〇〇以及輸出 負載20間。電流汲取模組122連接於發光二極體串1〇2以 及輸出負載22間。請再同時參照第3圖。第3圖為電流汲 取模組120以及輸出負載2〇更詳細之示意圖。電流没取模 組120包含運算放大器30以及開關金氧半電晶體32。開 φ 關金氧半電晶體32連接於所對應的發光二極體串100以及 輸出負載20。運算放大器30具有正輸入端（標記為+ )、 負輸入端（標記為_)以及輸出端。正輸入端用以接收設定 電壓Vset。負輸入端連接至輸出負載20以及開關金氧半電 晶體32,以將輸出負載20之電壓，亦即第3圖中標記為N 點之電壓，栓鎖於設定電壓準位Vset。運算放大器30的輸 出端連接至開關金氧半電晶體32之閘極。 電流鏡16包含：輸入分支160以及輸出分支162。輸 φ 入分支160根據可變設定負載161產生輸入設定電流 Isetl。換句話說，可變設定負載161可為一可變電阻，以 讓使用者可以藉由調整其阻值而改變輸入設定電流1setl 的大小。由於為電流鏡16之形式，輸出分支162可以依據 輸入設定電流Isetl產生輸出設定電流Iset2。 輸出分支162包含相串聯之第一負載163以及第二負 載165。於本實施例中，第一負載163以及第二負載165 均為電阻。於一實施例中，第一負載163亦可為一個二極 體以於其兩端得到一個電壓差。因此，在第一負載163以 201228476 及第二負載165上可根據輸出設定電流Iset2產生兩個電 壓。 於第二負載165上產生的電壓是做為前述之設定電壓 Vset ’並傳送至各電流汲取模組丨2〇及122的運算放大器 的正輸入端，以提供電壓栓鎖之機制。由於電壓栓鎖之機 制，輸出設定電流Iset2以及各個發光二極體串的發光二極 體電流（如第2圖及第3圖中繪示的發光二極體電流Id) 間具有之電流比值，與第二負載165以及輸出負載20間之 •電阻比值相同。舉例來說’當輸出負載20的阻值為IU， 且第二負載165之阻值為2〇〇*Rl，則輸出設定電流iset2 及發光二極體電流Id間的電流比值亦為2〇〇。 第一負載163上的電壓則做為可變參考電壓Vr，以傳 送至第1圖中所繪示的控制模組146。因此，控制模組146 實質上根據可變參考電壓Vr以及迴授電壓Vfb產生驅動電 壓Vd。需注意的是，迴授電壓vfb是根據此些發光二極體 串10其中之一的輸出端產生，如發光二極體串1〇〇的輸出 φ 端0。於一實施例中，迴授電壓Vfb可從這些輸出端的電 壓中，經由一個最小值選擇機制選擇出。 因此，當可變設定負載161的之阻值被改變，以使輸 入設定電流Isetl改變，輸出設定電流iset2將根據輸入設 定電流Isetl改變。而改變的設定電流iset2，將進一步使 可變參考電壓Vr以及發光二極體電流Id產生變動。 在一個例子中，於初始的運作模式下，發光二極體電 流Id為40毫安培，且可變參考電壓Vr為0.8伏特《當發 光二極體電路1的運作模式由於可變設定負載161被調整 201228476 至較小的值而改變，進一步使得發光二極體電流Id降至20 毫安培時，如控制模組146仍採用固定的參考電壓實現迴 授機制，則電流汲取模組將由於迴授機制將發光二極體串 的輸出端電壓栓鎖在固定的參考電壓值（即0.8V)附近， 而無法隨著降低發光二極體電流Id之調整而大幅降低其功 率消耗。 若控制模組146採用上述實施例中的可變參考電壓 Vr，則迴授控制機制將在運作模式改變（如發光二極體電 φ 流Id由40毫安培變為20毫安培）時，將由可變設定負載 161的變化，而調整可變參考電壓Vr至一個較小的值。因 此，發光二極體串的輸出端電壓將隨運作模式的改變而栓 鎖在較低的電壓值（如0.6伏特），功率可因此達到大幅下 降的效果。 舉例來說，在原運作模式下，迴授控制機制使發光二 極體串的輸出端電壓栓鎖在0.8伏特，則功率消耗將為0.8 伏特*40毫安培。如果採用固定參考電壓的方式，改變後 φ 的運作模式之功率消耗將為0.8伏特*20毫安培。另一方 面，如果採用可變參考電壓的方式，改變後的運作模式之 功率消耗將下降為0.6伏特*20毫安培。當發光二極體電路 中與所有的發光二極體串相連接的電流汲取模組均由於可 變參考電壓的設計而大幅降低功率消耗，則整體發光二極 體電路的功率消耗降低的量是非常可觀的。 需注意的是，第2圖中是以兩個發光二極體串為例進 行說。實質上，在不同的情形中，發光二極體串之數目可 進行不同之調整。Vfb produces a comparison result. The wave width modulator further generates a driving voltage Vd according to the comparison result and an oscillation signal. When the drive voltage Vd is high, the power amplifier 148 will be turned on. When the drive voltage Vd is low, the power amplifier 148 will be turned off. Power amplifier 148 can therefore be switched between on and off to charge and discharge capacitor 144. The charging and discharging process of the capacitor 144 allows the LED string 10 to be turned on or off. The current extraction modules 12 are respectively connected to one of the LED strings 10 to provide a voltage stabilization or current stabilization mechanism. Please also refer to the 2nd 201228476 chart. FIG. 2 is a schematic diagram of the current mirror of the jth diagram, the two LED arrays 1 and 102, and the two current extraction modules 12A and 122 in the embodiment of the disclosure. The current extraction module 120 is connected between the LED array 1 and the output load 20. The current extraction module 122 is connected between the LED array 1〇2 and the output load 22. Please refer to Figure 3 at the same time. Figure 3 is a more detailed schematic diagram of the current draw module 120 and the output load 2〇. The current modulo group 120 includes an operational amplifier 30 and a switching MOS transistor 32. The open φ-turned gold-oxygen semiconductor 32 is connected to the corresponding light-emitting diode string 100 and the output load 20. The operational amplifier 30 has a positive input (labeled as +), a negative input (labeled _), and an output. The positive input terminal is used to receive the set voltage Vset. The negative input is coupled to the output load 20 and the switching MOS transistor 32 to latch the voltage of the output load 20, i.e., the voltage labeled N at the third level, to the set voltage level Vset. The output of operational amplifier 30 is coupled to the gate of switching MOS transistor 32. Current mirror 16 includes an input branch 160 and an output branch 162. The input φ into branch 160 generates an input set current Iset1 in accordance with the variable set load 161. In other words, the variable set load 161 can be a variable resistor so that the user can change the magnitude of the input set current 1set1 by adjusting its resistance. Since it is in the form of a current mirror 16, the output branch 162 can generate an output set current Iset2 in accordance with the input set current Iset1. Output branch 162 includes a first load 163 and a second load 165 that are in series. In this embodiment, the first load 163 and the second load 165 are both resistors. In one embodiment, the first load 163 can also be a diode to obtain a voltage difference across its ends. Therefore, two voltages can be generated according to the output set current Iset2 at the first load 163 at 201228476 and the second load 165. The voltage generated at the second load 165 is the positive input of the operational amplifier that is supplied to the respective set voltages Vset' and transmitted to the current sinking modules 丨2 and 122 to provide a voltage latching mechanism. Due to the voltage latching mechanism, the output set current Iset2 and the LED current of each of the LED strings (such as the LED current Id shown in FIGS. 2 and 3) have a current ratio. The resistance ratio between the second load 165 and the output load 20 is the same. For example, when the resistance of the output load 20 is IU, and the resistance of the second load 165 is 2〇〇*R1, the current ratio between the output set current iset2 and the LED current Id is also 2〇〇. . The voltage on the first load 163 is then used as a variable reference voltage Vr for transmission to the control module 146 depicted in FIG. Therefore, the control module 146 generates the driving voltage Vd substantially based on the variable reference voltage Vr and the feedback voltage Vfb. It should be noted that the feedback voltage vfb is generated according to the output end of one of the light-emitting diode strings 10, such as the output φ terminal 0 of the light-emitting diode string 1〇〇. In one embodiment, the feedback voltage Vfb can be selected from the voltages at these outputs via a minimum selection mechanism. Therefore, when the resistance value of the variable set load 161 is changed so that the input set current Iset1 is changed, the output set current iset2 will be changed in accordance with the input set current Iset1. The changed set current iset2 will further vary the variable reference voltage Vr and the light-emitting diode current Id. In one example, in the initial mode of operation, the LED current Id is 40 milliamperes and the variable reference voltage Vr is 0.8 volts. "When the operating mode of the LED circuit 1 is changed due to the variable set load 161 Adjusting 201228476 to a smaller value and changing, further reducing the LED current Id to 20 mA. If the control module 146 still uses a fixed reference voltage to implement the feedback mechanism, the current capture module will be fed back. The mechanism latches the output voltage of the LED string near a fixed reference voltage value (ie, 0.8V), and cannot significantly reduce its power consumption as the LED dipole current Id is adjusted. If the control module 146 adopts the variable reference voltage Vr in the above embodiment, the feedback control mechanism will be changed when the operation mode is changed (for example, the LED φ current Id is changed from 40 mA to 20 mA). The change of the load 161 is variably set, and the variable reference voltage Vr is adjusted to a smaller value. Therefore, the output voltage of the LED string will be latched at a lower voltage value (e.g., 0.6 volts) as the operating mode changes, and the power can be drastically reduced. For example, in the original mode of operation, the feedback control mechanism causes the output voltage of the LED string to be latched at 0.8 volts, and the power consumption will be 0.8 volts * 40 milliamps. If a fixed reference voltage is used, the power consumption of the operating mode after the change of φ will be 0.8 volts * 20 mA. On the other hand, if a variable reference voltage is used, the power consumption of the changed operating mode will drop to 0.6 volts * 20 mA. When the current extraction module connected to all the LED strings in the LED circuit greatly reduces the power consumption due to the design of the variable reference voltage, the power consumption of the overall LED circuit is reduced. Very impressive. It should be noted that in the second figure, two LED strings are taken as an example. In essence, the number of LED strings can be adjusted differently in different situations.
12 201228476 請參照第4圖。第4圖為本揭示内容一實施例中，一 種發光二極體電路運作方法之流程圖。發光二極體電路運 作方法可應用於如第1圖所繪示的發光二極體電路1中。 發光二極體電路運作方法包含下列步驟（應瞭解到’在本 實施方式中所提及的步驟’除特別敘明其順序者外，均可 依實際需要調整其前後順序’甚至可同時或部分同時執 行）。12 201228476 Please refer to Figure 4. FIG. 4 is a flow chart of a method for operating a light emitting diode circuit according to an embodiment of the disclosure. The illuminating diode circuit operation method can be applied to the illuminating diode circuit 1 as shown in Fig. 1. The operation method of the LED circuit includes the following steps (it should be understood that the steps mentioned in the present embodiment can be adjusted according to actual needs, except for the order in which the sequence is specifically described, 'even simultaneously or partially Simultaneous execution).
於步驟401，根據可變設定負載161於電流鏡16之輸 入分支160產生輸入設定電流1setl。接著於步驟402 ’根 據輸入設定電流Isetl於電流鏡16之輸出分支162產生輸 出設定電流Iset2，其中輸出分支丨62包含相串聯之第一負 載163以及第二負載165 ’以分別根據輸出設定電流iset2 產生可變參考電壓Vr以及設定電壓Vset。於步驟403，將 連接於發光二極體串10其中之一之輸出負載之電壓栓鎖 於設定電壓準位Vset。於步驟404，由發光二極體電路1 之控制模組146接收可變參考電壓Vr以及自發光二極體串 10之複數個輸出端其中之一之迴授電壓Vfb，以控制功率 放大器148之閘極’以進一步控制發光二極體串1〇之運作。 應用本揭示内容之優點在於藉由可變設定負載以及電 抓鏡之设置，建立一個可隨運作模式改變的可變參考電 麗以在切換至不同的運作模式時動態地調整迴授控制機 制的運作，達到降低功率消耗的功效。 雖然本揭示内容已以實施方式揭露如上，缺直並非用 二定：揭示内容’任何熟習此技藝者，在不脫離本揭示 内谷之精神和範_，當可作各種之更動與潤飾，因此本In step 401, an input set current 1set1 is generated in the input branch 160 of the current mirror 16 based on the variable set load 161. Next, in step 402', an output set current Iset2 is generated in the output branch 162 of the current mirror 16 according to the input set current Iset1, wherein the output branch 62 includes a first load 163 and a second load 165' connected in series to respectively set the current iset2 according to the output. A variable reference voltage Vr and a set voltage Vset are generated. In step 403, the voltage of the output load connected to one of the LED strings 10 is latched to the set voltage level Vset. In step 404, the control module 146 of the LED circuit 1 receives the variable reference voltage Vr and the feedback voltage Vfb of one of the plurality of outputs of the self-luminous diode string 10 to control the power amplifier 148. The gate 'to further control the operation of the LED string 1〇. The advantage of the application of the present disclosure is that a variable reference voltage that can be changed with the operation mode is established by the variable setting load and the setting of the electric lens to dynamically adjust the feedback control mechanism when switching to different operation modes. Operate to achieve the effect of reducing power consumption. Although the present disclosure has been disclosed in the above embodiments, the lack of straightness is not intended to be inconsistent: the disclosure of the content of any person skilled in the art, without departing from the spirit and scope of the present disclosure, can be used for various changes and retouching, therefore
13 201228476 揭示内容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】 為讓本揭示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圖為本揭示内容之一實施例中，發光二極體電路 之示意圖； 第2圖為本揭示内容一實施例中，第1圖中的電流鏡、 兩個發光二極體串以及兩個電流汲取模組之示意圖； 第3圖本揭示内容一實施例中，第2圖中的電流汲取 模組以及輸出負載更詳細之示意圖；以及 第4圖為本揭示内容一實施例中，一種發光二極體電 路運作方法之流程圖。 【主要元件符號說明】 1 :發光二極體電路 100、102 :發光二極體串 120、122 :電流汲取模組 142 :二極體 146 :控制模組 16 :電流鏡 161 :可變設定負載 163 :第一負載 20、22 :輸出負載 10 :複數發光二極體串 12 :複數電流汲取模組 140 :電感 144 :電容 148 :功率放大器 160 :輸入分支 162 :輸出分支 165 :第二負載 30 :運算放大器 14 201228476 32 :開關金氧半電晶體 401-404 :步驟13 201228476 The scope of protection of the disclosure is subject to the definition of the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, advantages and embodiments of the present disclosure will become more apparent and understood. 2 is a schematic diagram of a current mirror, two LED strings, and two current capture modules in FIG. 1 according to an embodiment of the disclosure; In one embodiment, the current extraction module and the output load in FIG. 2 are more detailed; and FIG. 4 is a flow chart of a method for operating the LED circuit according to an embodiment of the disclosure. [Main component symbol description] 1 : LED circuit 100, 102: LED series 120, 122: Current extraction module 142: Diode 146: Control module 16: Current mirror 161: Variable setting load 163: first load 20, 22: output load 10: complex light-emitting diode string 12: complex current extraction module 140: inductor 144: capacitor 148: power amplifier 160: input branch 162: output branch 165: second load 30 : Operational Amplifier 14 201228476 32 : Switching MOS Half-Transistor 401-404: Steps
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