M405705 五、新型說明： 【新型所屬之技術領域】 [0001] 本新型涉及電源供應系統，尤其涉及一種發光二極體驅 動系統。 【先前技術】 [0002] 在高對比與環保要求下，發光二極體取代冷陰極螢光燈 成為液晶顯示幕背光源技術是時下的發展趨勢。在液晶 顯示幕中，發光二極體一般採用多串並聯的架構。在此 架構下，為保證各串發光二極體的電流平衡，每_發光 二極體均需連接一組電壓和/或電流偵測電路及開關，來 偵測電壓和/或電流並迴授至赢衝寬度調變控制器，由脈 衝寬度調變控制器控制輸出至各串發光二極體的電壓並 調整各串發光二極體的開關，以調整電流。此架構及控 制方法較為複雜，且造成產品成本的增加。 【新型内容】 [0003] 有鑑於此，需提供一種發光二極體驅動系統，控制簡單 且具有較低的成本。 [0004] 一種發光二極體驅動系統，用於驅動複數發光二極體串 ，包括轉換器、控制器、複數主動限流電路及複數過壓 保護電路。轉換器用於將外部電源訊號轉換為直流電源 訊號，驅動該等發光二極體_。控制器用於控制該轉換 器。該等主動限流電路與該等發光二極體串一一對應相 連，分別包括第一開關元件及第二開關元件。第一開關 元件包括控制極、第一電極及第二電極，該控制極接收 表單編號A0101 第3頁/共18頁 M405705 參考電壓，該第一電極連接對應的發光二極體串，該第 二電極經由第一電阻接地。第二開關元件包括控制極、 第电極及第二電極，該第二開關元件的控制極經由第 二電阻連接該第一開關元件的第二電極，該第二開關元 [0005] [0006] [0007] [0008] 件的第一電極接收該參考電壓 ________ 電極接地。該等過壓保護電路與該等發光二極體串 對應相連，分別包括稽納二極體、第三開關元件及第一 電谷。稽納二極體的陰極連接對應的發光二極體串，陽 極連接第三電阻包括控制極、第 一電極及第二電極^ 三電阻的另二_，該第 考電壓，該蒙主開關元件的| 一端連接該第三電阻的另 優選地，魅祕料路還包括減^:與該第一 阻並聯。 举’ ? i Ϊ'nipfiprii in? 優選地，該熱敏元件為負遠敏慮阻。 ：' r i- ^ 優選地，1¾第一開關元件“㉝讲$第二開關元件的 第一電極及該第三開關元件的第_電極經由第四電阻接 收該參考電壓。 該第二開關元件的第M405705 V. New Description: [New Technology Field] [0001] The present invention relates to a power supply system, and more particularly to a light-emitting diode driving system. [Prior Art] [0002] Under the high contrast and environmental protection requirements, the replacement of cold cathode fluorescent lamps by light-emitting diodes has become the current development trend of liquid crystal display backlight technology. In the liquid crystal display, the light-emitting diodes generally adopt a multi-parallel connection structure. Under this architecture, in order to ensure the current balance of each string of LEDs, a set of voltage and / or current detection circuits and switches are connected to each of the LEDs to detect voltage and / or current and feedback To the win width modulation controller, the pulse width modulation controller controls the voltage output to each string of LEDs and adjusts the switches of each string of LEDs to adjust the current. This architecture and control method are complex and result in an increase in product cost. [New content] [0003] In view of the above, it is necessary to provide a light-emitting diode driving system with simple control and low cost. [0004] A light emitting diode driving system for driving a plurality of LED strings, including a converter, a controller, a plurality of active current limiting circuits, and a plurality of overvoltage protection circuits. The converter is used to convert the external power signal into a DC power signal to drive the LEDs _. The controller is used to control the converter. The active current limiting circuits are connected in one-to-one correspondence with the LED strings, and respectively include a first switching element and a second switching element. The first switching element includes a control electrode, a first electrode and a second electrode, and the control electrode receives the reference voltage of the form number A0101, page 3/18, M405705, the first electrode is connected to the corresponding LED string, the second The electrode is grounded via a first resistor. The second switching element includes a control electrode, a first electrode and a second electrode, and a control electrode of the second switching element is connected to the second electrode of the first switching element via a second resistor, the second switching element [0005] [0008] The first electrode of the device receives the reference voltage ________ electrode grounded. The overvoltage protection circuits are connected to the LED strings, and respectively comprise a Zener diode, a third switching element and a first valley. The anode of the second diode is connected to the corresponding LED string, and the third resistor of the anode is connected to the second electrode of the control electrode, the first electrode and the second electrode, and the first test voltage, the main switch element Further preferably, the one end is connected to the third resistor, and the charm path further comprises a subtraction: in parallel with the first resistor. Preferably, the thermal element is negatively sensitive. : ' r i- ^ Preferably, the first switching element "33" indicates that the first electrode of the second switching element and the _ electrode of the third switching element receive the reference voltage via the fourth resistor. The second switching element First
1極連接該第 接收該參 一電容的 電 優選地’該第一開關元件及該第二開關元件均為雙載子 接面電晶體，該第三開關元件為電晶體，該第—開關元 件、該第二開關元件及該第三開關元件的控制極均為基 極，該第一開關元件、該第二開關元件及該第三開關元 件的第一電極均為集極，該第一開關元件、該第二開關 表單編號A0101 第4頁/共18頁 M405705 元件及該第三開關元件的第二電極均為射極。 闺優選地，該轉換器包括電感、苐四開關元件及整流遽波 電路。電感的一端接收該外部電源訊號。第四開關元件 與垓電感的另一端相連，用於轉換該外部電源訊號’包 括控制極。整流濾波電路與該第四開關元件相連並連接 於該電感的另一端與該等發光二極體串之間，用於將該 轉換後的外部電源訊號整流濾波為該直流電源訊號。 [0010] 優選地，該整流濾波電路包括第一二極體及第二電容。 第一二極體的陽極連接該電感的另一端，陰極連接該等 發光二極體串。第二電容的一端連接該第一二極體的陰 極，另一端接地® [0011] 上述發光二極體驅動系統利用兩個開關元件進行電流限 制，利用稽納二極體及開關元件進行過壓保護，無需控 制器進行控制，控制簡單，實現容易，且成本較低。 【實施方式】 [0012]圖1為本新型一實施方式中發光二極體驅動系統10的示意 圖。在本實施方式中’發光二極體驅動系統10用於驅動 複數發光二極體串S1，其包括控制器100、轉換器110、 複數主動限流電路120及複數過壓保護電路130。其中， 主動限流電路120、過壓保護電路130及發光二極體串si 的數目相同，且主動限流電路12〇及過壓保護電路130與 發光二極體串S1--對應連接。轉換器110用於將外部電 源訊號Vin轉換為直流電源訊號，驅動發光二極體串si » 在本實施方式中，外部電源訊號V i η為直流電源訊號，轉 表單編號Α0101 第5頁/共18頁 M405705 換器110將外部直流電源訊號Vi η轉換為合適驅動發光二 極體串S1的直流電源訊號，並輸出至發光二極體串S1的 第一個發光二極體的陽極，其包括升壓（boost)、降壓 (buck)、隔離型、非隔離型、半橋及全橋等架構。控 制器100用於控制轉換器110。 [0013] 主動限流電路120、過壓保護電路130分別與發光二極體 串S1--對應相連。在本實施方式中，一個主動限流電 路120、一個過壓保護電路130分別連接一個發光二極體 串S1的最後一個發光二槔.韓_璣#，,穩*2為本新型一實施 方式中發光二極g 如圖2所示 ，每個主動限P電路120包_^^^^、第二開關 元件Q2、第一電阻R1及第元件Q1包 括控制極、第一電極及第二電極，該接收參考電 翁’ 壓Vcc，該第一電極連接對應的發光二串S1，該第二 電極經由第一電阻R1接地。， μ ，The first pole is connected to the first capacitor and the second switching component is a bipolar junction transistor, and the third switching component is a transistor, and the first switching component is a transistor The second switching element and the control electrode of the third switching element are both bases, and the first switching element, the second switching element and the first electrode of the third switching element are collectors, and the first switch The component, the second switch form number A0101, the fourth electrode, the M405705 component, and the second electrode of the third switching component are both emitters. Preferably, the converter comprises an inductor, a quadrupole switching element and a rectifying chopper circuit. One end of the inductor receives the external power signal. The fourth switching element is coupled to the other end of the germanium inductor for converting the external power signal 'including the gate. The rectifying and filtering circuit is connected to the fourth switching element and connected between the other end of the inductor and the LED strings for rectifying and filtering the converted external power signal into the DC power signal. [0010] Preferably, the rectifying and filtering circuit comprises a first diode and a second capacitor. The anode of the first diode is connected to the other end of the inductor, and the cathode is connected to the string of the LEDs. One end of the second capacitor is connected to the cathode of the first diode, and the other end is grounded. [0011] The above-mentioned LED driving system utilizes two switching elements for current limiting, and overvoltage is performed by using the Zener diode and the switching element. Protection, no need for controller control, simple control, easy implementation, and low cost. [Embodiment] FIG. 1 is a schematic view of a light-emitting diode driving system 10 according to an embodiment of the present invention. In the present embodiment, the LED driving system 10 is used to drive the complex LED string S1, which includes the controller 100, the converter 110, the complex active current limiting circuit 120, and the complex overvoltage protection circuit 130. The number of the active current limiting circuit 120, the overvoltage protection circuit 130, and the LED string si is the same, and the active current limiting circuit 12 and the overvoltage protection circuit 130 are connected to the LED string S1--. The converter 110 is configured to convert the external power signal Vin into a DC power signal to drive the LED string si » In the embodiment, the external power signal V i η is a DC power signal, and the form number is Α0101. The M405705 converter 110 on page 18 converts the external DC power signal Vi η into a DC power signal suitable for driving the LED string S1 and outputs it to the anode of the first LED of the LED string S1, which includes Boost, buck, isolated, non-isolated, half-bridge, and full-bridge architectures. Controller 100 is used to control converter 110. [0013] The active current limiting circuit 120 and the overvoltage protection circuit 130 are respectively connected to the LED array S1--. In the present embodiment, an active current limiting circuit 120 and an overvoltage protection circuit 130 are respectively connected to the last one of the LED strings S1. Han_玑#, and the stable *2 is an embodiment of the present invention. The middle light-emitting diodes g, as shown in FIG. 2, each active-limit P circuit 120 includes a control electrode, a first electrode, and a second electrode. The second switching element Q2, the first resistor R1, and the second element Q1 include a control electrode, a first electrode, and a second electrode. The receiving reference voltage is Vcc, the first electrode is connected to the corresponding two strings S1, and the second electrode is grounded via the first resistor R1. , μ ,
Intellectual [0014] 第二開關元件Q2包括控制#f、r第摩择/及第二電極，第 " s·- . · - 裊}j 〜** 二開關元件Q2的控制極經二$便^2連接第一開關元 件Q1的第二電極，第二開關元件Q2的第一電極接收參考 電壓Vcc，第二開關元件Q2的第二電極接地。 [0015] 過壓保護電路130包括稽納二極體ZD1、第三電阻R3、第 三開關元件Q3及第一電容C1。稽納二極體ZD1的陰極連接 對應的發光二極體串S1，陽極連接第三電阻R3的一端。 第三開關元件Q3包括控制極、第一電極及第二電極，第 三開關元件Q3的控制極連接第三電阻R3的另一端，第三 開關元件Q3的第一電極接收參考電壓Vcc，第三開關元件 表單編號A0101 第6頁/共18頁 電谷C1 一端連接第三電阻R3的 Q3的第二電極接地。第 另—端，另一端接地。 [0016]在本實施方式中，第-灿λ 元件Q2的第心 控制極、第二開關 電極經由第 辑Q2的第-電極及第三開關元件们的第一 四電阻R4接收參考電壓vCc。 [0017] ’第-開關元_及第二開關元㈣均 t載子接㈣體，第一 2疋侧、第二開關科Q2及第三開關元件Q3的控制 極均為基極，第-開__ '第二_元件⑽及第三 開關几件_第-電極均為集極，第—開關元·、第 二開關.元件Q2及第三開關元件Q3的第二電極均為射極。 在本新型的另~~實施方式中H關it_及第二開 關7L件Q2為電晶體或金屬氧化物半導體場效應電 晶體， 第二開關元件Q3為雙載子接面電晶體或金屬氧化物半導 體場效應電晶體。 [0018]在本實施方式中，當流經發光二極體串S1的電流正常時 ，第一開關元件Q1導通，第二開關元件Q2截止。當流經 發光二極雜串S1的電流增大’第一電阻以上的分壓增大 ，當增大到Λ於第二開關元件Q2的導通電壓時’第二開 關元件Q2導通。因而，參考電壓Vcc經由第四電阻R4接地 ，從而第〆開關元件Q1的基極電壓降低，使得第一開關 元件Q1载土，從而切斷發光二極體串S1的回路，以限制 電流。如此，無需控制器1 00，即可限制增大的電流’保 護發光二極艏串以。 表單煸號A0101 第7頁/共18頁 [0019]Μ4ϋ^ 當發光二極體_S1正常工作時，第三開關元件Q3截止。 當過壓時’稽納二極體ZD1反向擊穿，且第三電阻R3及第 -電容C1上的分壓增加，使得第三關元⑽導通。因 而’參考電壓Vcc經由第四電阻R4接地，從而第一開關元 件Q1的基極電壓降低，使得第—開關元件Ql截止。如此 ’無需控制器1GG，即可進行過壓保護，保護發光二極體 串S1。 [0020] 圖3所示為本新型另一實施方式中發光二極雜驅動系統2〇 的具體電路®。在本實|挤增_極體㈣系統 20與圖2中發光主動限流電 路具體電路’其餘架;詳述。圖3 中的主動限流電路220與圖的區別 在於還包括熱敏元件Rtl，與第一電阻聯。因為第一 開關元件Q1與第二開丽元件Q2的導通隨溫度增加而 降低，因而，在第一電阻丰聯熱敏元件Rtl進行溫度 補償。在本實施方式中，溫度係數熱敏 Γ ·*'Γ.ί'；*' )<：ΐΓ|ν 電阻，其電阻隨温度升高一電阻R1並聯後 . λ t ；·λ 必W· ‘ ，總電阻減小。從而流經發光二極體串Si的電流超過預 定值時’才使第二開關元件Q2導通，進行限流，避免流 經發光二極體串S1的電流未達到預定值時，第二開關元 件Q2即導通，產生誤動作。 [0021] 在圖1至圖3中’參考電壓Vcc由額外的電壓源提供。在另 一實施方式中，參考電壓Vcc也可直接由轉換器110提供 [0022] 圖4所示為本新型一實施方式中轉換器11〇的具體電路圖 表單編號A0101 第8頁/共18頁 M405705 。在本實施方式中，轉換器110為升壓架構，包括電感L 、第四開關元件Q4及整流濾波電路。整流濾波電路包括 第一二極體D及第二電容C2。電感L一端接收外部電源訊 號Vin，另一端連接整流濾波電路的第一二極體D的陽極 。第四開關元件Q4與電感L的另一端相連，用於轉換外部 電源訊號Vin，包括控制極、第一電極及第二電極。第四 開關元件Q4的控制極連接控制器100，第一電極連接電感 L的另一端，第二電極接地。在本實施方式中，第四開關 元件Q4為金屬氧化物半導體場效應管，控制極為閘極， 第一電極為汲極，第二電極為源極。 [0023] 整流濾波電路與第四開關元件Q4相連並連接於電感L的另 一端與發光二極體串S1之間，用於將轉換後的外部電源 訊號整流濾波為該直流電源訊號。第一二極體D1陽極連 接電感L的另一端，陰極連接發光二極體串S1。第二電容 C2—端連接第一二極體D1的陰極，另一端接地。在本新 型的另一實施方式中，轉換器110還包括降壓、隔離型、 非隔離型、半橋及全橋等架構。控制器100用於產生並輸 出控制訊號至轉換器110的第四開關元件Q4的控制極，以 控制第四開關元件Q4的開關，從而進行外部電源訊號的 轉換。 [0024] 發光二極體驅動系統10利用兩個開關元件Q1及Q2進行電 流限制，利用稽納二極體ZD1及開關元件Q3進行過壓保護 ，無需控制器進行控制，控制簡單，實現容易，且成本 較低。 [0025] 綜上所述，本新型符合新型專利要件，爰依法提出專利 表單編號A0101 第9頁/共18頁 M405705 申請。惟，以上所述者僅為本新型之較佳實施例，舉凡 熟悉本案技藝之人士，在菱依本案新型精神所作之等效 修飾或變化，皆應包含於以下之申請專利範圍内。 【圖式簡單說明】 [0026]圖1為本新型一實施方式中發光二極體驅動系統的示意圖 [0027]圖2為本新型一實施方式中發光二極體驅動系統的具體電 路圖； ν'»Intellectual [0014] The second switching element Q2 includes a control #f, a second selection/and a second electrode, and a " s·-. - - 袅}j ** ** control element of the second switching element Q2 ^2 connects the second electrode of the first switching element Q1, the first electrode of the second switching element Q2 receives the reference voltage Vcc, and the second electrode of the second switching element Q2 is grounded. [0015] The overvoltage protection circuit 130 includes a Zener diode ZD1, a third resistor R3, a third switching element Q3, and a first capacitor C1. The cathode of the Zener diode ZD1 is connected to the corresponding LED string S1, and the anode is connected to one end of the third resistor R3. The third switching element Q3 includes a control electrode, a first electrode and a second electrode, the control electrode of the third switching element Q3 is connected to the other end of the third resistor R3, and the first electrode of the third switching element Q3 receives the reference voltage Vcc, and the third Switching element form No. A0101 Page 6 of 18 Electric Valley C1 One end of Q3 connected to the third resistor R3 is grounded. The other end is grounded at the other end. In the present embodiment, the first center control electrode and the second switching electrode of the first-thickness λ element Q2 receive the reference voltage vCc via the first electrode of the first Q2 and the first four-resistor R4 of the third switching element. [0017] 'The first switch element _ and the second switch element (four) are both t-sub-connected (four) body, the control poles of the first 2 疋 side, the second switch section Q2 and the third switching element Q3 are bases, the first - __ 'The second_element (10) and the third switch _ the first electrode are collectors, the first switch element, the second switch. The second electrode of the element Q2 and the third switching element Q3 are both emitters . In another embodiment of the present invention, the H off it_ and the second switch 7L Q2 are transistors or metal oxide semiconductor field effect transistors, and the second switching element Q3 is a bipolar junction transistor or metal oxide. Semiconductor field effect transistor. In the present embodiment, when the current flowing through the light-emitting diode string S1 is normal, the first switching element Q1 is turned on, and the second switching element Q2 is turned off. When the current flowing through the light-emitting diode string S1 increases, the partial pressure above the first resistance increases, and when it increases to the ON voltage of the second switching element Q2, the second switching element Q2 is turned on. Thus, the reference voltage Vcc is grounded via the fourth resistor R4, so that the base voltage of the second switching element Q1 is lowered, so that the first switching element Q1 is loaded, thereby cutting off the loop of the LED string S1 to limit the current. Thus, without the controller 100, the increased current can be limited to protect the LED array. Form nickname A0101 Page 7 of 18 [0019] Μ 4 ϋ ^ When the light-emitting diode _S1 is operating normally, the third switching element Q3 is turned off. When overvoltage occurs, the output voltage of the Zener diode ZD1 is reversed, and the voltage division across the third resistor R3 and the first capacitor C1 is increased, so that the third gate (10) is turned on. Therefore, the reference voltage Vcc is grounded via the fourth resistor R4, so that the base voltage of the first switching element Q1 is lowered, so that the first switching element Q1 is turned off. Thus, the overvoltage protection can be performed without the controller 1GG, and the light-emitting diode string S1 is protected. [0020] FIG. 3 shows a specific circuit® of the illuminating two-pole hybrid driving system 2〇 according to another embodiment of the present invention. In the actual | squeezed _ polar body (four) system 20 and the illuminating active current limiting circuit specific circuit in Figure 2 'the rest of the frame; detailed. The active current limiting circuit 220 of Figure 3 differs from the Figure in that it further includes a thermal element Rtl coupled to the first resistor. Since the conduction between the first switching element Q1 and the second opening element Q2 decreases as the temperature increases, temperature compensation is performed at the first resistance-cobalced element Rtl. In the present embodiment, the temperature coefficient is sensitive Γ ·*'Γ.ί';*' )<:ΐΓ|ν resistance, whose resistance increases with temperature and a resistor R1 is connected in parallel. λ t ;·λ must be W· ', the total resistance is reduced. Therefore, when the current flowing through the light-emitting diode string Si exceeds a predetermined value, the second switching element Q2 is turned on to perform current limiting to prevent the current flowing through the light-emitting diode string S1 from reaching a predetermined value, and the second switching element Q2 is turned on, causing malfunction. [0021] In FIGS. 1 through 3, the reference voltage Vcc is provided by an additional voltage source. In another embodiment, the reference voltage Vcc can also be directly provided by the converter 110. [0022] FIG. 4 is a specific circuit diagram of the converter 11A according to an embodiment of the present invention. Form No. A0101 Page 8 of 18 M405705 . In the present embodiment, the converter 110 is a boosting architecture including an inductor L, a fourth switching element Q4, and a rectifying and filtering circuit. The rectifying and filtering circuit includes a first diode D and a second capacitor C2. One end of the inductor L receives the external power signal Vin, and the other end is connected to the anode of the first diode D of the rectifying and filtering circuit. The fourth switching element Q4 is connected to the other end of the inductor L for converting the external power signal Vin, including the control electrode, the first electrode and the second electrode. The control electrode of the fourth switching element Q4 is connected to the controller 100, the first electrode is connected to the other end of the inductor L, and the second electrode is grounded. In the present embodiment, the fourth switching element Q4 is a metal oxide semiconductor field effect transistor, and the gate electrode is controlled, the first electrode is a drain, and the second electrode is a source. [0023] The rectifying and filtering circuit is connected to the fourth switching element Q4 and connected between the other end of the inductor L and the LED string S1 for rectifying and filtering the converted external power signal into the DC power signal. The anode of the first diode D1 is connected to the other end of the inductor L, and the cathode is connected to the LED string S1. The second capacitor C2 is connected to the cathode of the first diode D1 and the other end is grounded. In another embodiment of the new type, converter 110 also includes buck, isolated, non-isolated, half bridge, and full bridge architectures. The controller 100 is configured to generate and output a control signal to the gate of the fourth switching element Q4 of the converter 110 to control the switching of the fourth switching element Q4 to perform conversion of the external power signal. [0024] The LED driving system 10 uses two switching elements Q1 and Q2 for current limiting, and uses the Zener diode ZD1 and the switching element Q3 for overvoltage protection, which does not require control by the controller, and the control is simple and easy to implement. And the cost is lower. [0025] In summary, the present invention conforms to the new patent requirements, and is filed according to law. Form No. A0101 Page 9 of 18 M405705 Application. However, the above-mentioned ones are only preferred embodiments of the present invention, and those skilled in the art, which are equivalent to the novelty of the present invention, should be included in the following claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a light emitting diode driving system according to an embodiment of the present invention. FIG. 2 is a specific circuit diagram of a light emitting diode driving system according to an embodiment of the present invention; »
統的轉換器 [。_ 為本新型另一娜觸統的具體 電路圖；及。 ’ [0029] 圖4為本新型一實施方式中 的具體電路圖。 【主要元件符號說明】 [0030] [0031] [0032] [0033] [0034] [0035] [0036] [0037] 發光二極體驅動系統：10礙ectua ·'、· 控制器：100 Ρ i ·1·!. · 轉換器：110 主動限流電路：120、220 過壓保護電路：130 第一至第四開關元件：Ql、Q2、Q3、Q4 第一至第四電阻：Rl、R2、R3、R4 稽納二極體：ZD1 表單編號Α0101 第丨0頁/共18頁 M405705System converter [. _ This is the specific circuit diagram of another new type of touch system; and. [0029] FIG. 4 is a specific circuit diagram of an embodiment of the present invention. [0010] [0037] [0037] [0037] [0037] Light-emitting diode drive system: 10 ectua · ', · Controller: 100 Ρ i ·1·!. · Converter: 110 Active current limiting circuit: 120, 220 Overvoltage protection circuit: 130 First to fourth switching components: Ql, Q2, Q3, Q4 First to fourth resistors: Rl, R2 R3, R4 Jenus diode: ZD1 Form number Α 0101 Page 0 of 18 M405705
[0038] 第一及第二 電容 ：Cl ' C2 [0039] 熱敏元件： Rtl [0040] 電感：L [0041] 二極體：D [0042] 外部電源訊號： Vin [0043] 參考電壓： Vcc [0044] 發光二極體串： SI 表單編號A0101 第11頁/共18頁[0038] First and second capacitors: Cl ' C2 [0039] Thermal element: Rtl [0040] Inductance: L [0041] Diode: D [0042] External power supply signal: Vin [0043] Reference voltage: Vcc [0044] LED String: SI Form No. A0101 Page 11 of 18