TWM411067U

TWM411067U - Non-isolated flyback boost converter

Info

Publication number: TWM411067U
Application number: TW100206875U
Authority: TW
Inventors: Li-Wei Lin; Zuo-Shang Yu
Original assignee: Top Victory Invest Ltd
Priority date: 2011-04-20
Filing date: 2011-04-20
Publication date: 2011-09-01

Description

Μ411Ό67 五、新型說明：【新型所屬之技術領域】 [0001] 本創作是有關於一種用以驅動發光二極體 (Light-Emitting Diode，簡稱LED)光源的升壓轉換器，且特別是有關於一種用以驅動LED光源的非隔離型反驰式升壓轉換器。【先前技術】 [0002] 圖1為一種採用傳統升壓轉換器的LED驅動電路方塊圖。請參照圖1，LED驅動電路1用以驅動LED光源3，LED 光源3具有輸入端及輸出端。LED驅動電路1包括電磁干擾 (ElectroMagnetic Interference，簡稱EMI)遽波器 11、整流濾波器12、隔離型反驰式轉換器13、升壓轉換器14及控制器15。EMI濾波器11、整流濾波器12及隔離型反馳式轉換器1 3組成直流電源供應器以提供具有隔離特性的直流輸入電壓Vn。EMI濾波器11用以接收交流電源VAf^並濾除交流電源的電磁雜訊。整流濾波器12耦接EMI濾波器11，用以將濾除電磁雜訊後的交流電源Va 整流及濾波成直流電源VDe。隔離型反驰式轉換器13耦接整流濾波器12，用以接收直流電源VDe並將直流電源VDe 轉換成具有隔離特性的直流輸入電壓vu。 [0003] 傳統的升壓轉換器14包括電感器L1、功率開關Q1、二極體D1及電容器C1。升壓轉換器14耦接隔離型反馳式轉換器13，用以接收輸入電壓Vn並將輸入電壓Vn升壓成輸出電壓Vy以提供至LED光源3的輸入端。若忽略二極體D1的導通壓降，假設功率開關Q1的責任週期（duty 表單編號A0101 第3頁/共17頁 M411067 cycle)為Dd，則傳統的升壓轉換器14的電壓增益為Μ411Ό67 V. New Description: [New Technology Field] [0001] The present invention relates to a boost converter for driving a Light-Emitting Diode (LED) light source, and in particular A non-isolated fly-back boost converter for driving an LED light source. [Prior Art] [0002] Fig. 1 is a block diagram of an LED driving circuit using a conventional boost converter. Referring to FIG. 1 , the LED driving circuit 1 is used to drive the LED light source 3 , and the LED light source 3 has an input end and an output end. The LED drive circuit 1 includes an Electromagnetic Interference (EMI) chopper 11, a rectification filter 12, an isolated flyback converter 13, a boost converter 14, and a controller 15. The EMI filter 11, the rectifying filter 12, and the isolated flyback converter 13 constitute a DC power supply to provide a DC input voltage Vn having an isolation characteristic. The EMI filter 11 is for receiving the AC power source VAf^ and filtering out the electromagnetic noise of the AC power source. The rectifying filter 12 is coupled to the EMI filter 11 for rectifying and filtering the AC power source Va after filtering the electromagnetic noise into a DC power source VDe. The isolated flyback converter 13 is coupled to the rectification filter 12 for receiving the DC power source VDe and converting the DC power source VDe into a DC input voltage vu having an isolation characteristic. The conventional boost converter 14 includes an inductor L1, a power switch Q1, a diode D1, and a capacitor C1. The boost converter 14 is coupled to the isolated flyback converter 13 for receiving the input voltage Vn and boosting the input voltage Vn to the output voltage Vy for supply to the input of the LED light source 3. If the turn-on voltage drop of the diode D1 is ignored, assuming that the duty cycle of the power switch Q1 (duty form number A0101, page 3 / page 17 M411067 cycle) is Dd, the voltage gain of the conventional boost converter 14 is

DD

Vn l-DVn l-D

[0004] 控制器15採用脈寬調變（Pulse-Width Modula-tion，簡稱PWM)控制器，其耦接LED光源3的輸出端及升壓轉換器14的功率開關Q1，用以接收LED光源3的輸出電流1^，並根據輸出電流Im在其回饋端產生的回饋電壓輸出PWM形式的控制信號CTL，以控制功率開關Q1的責任週期，進而改變輸出電壓Vy。控制器15另接收致能信號EN 及調光信號DIM，其中致能信號EN用以決定LED光源3是否工作，調光信號DIM用以決定LED光源3的亮度。 [0005] 傳統的升壓轉換器14因受限於功率開關Q1的責任週期Dd及用於儲能的電感器L1的元件物理特性影響，在實 Ο 際的應用中，無法具有很高的電壓增益。當應用於低電壓輸入場合下，傳統的升壓轉換器存在著輸出電壓無法提升的問題。當應用於高電壓輸出場合下，往往需要串接兩個以上傳統的升壓轉換器來提供高輸出電壓的需求，如此將增加設計的成本及電路的複雜度。【新型内容】 [0006] 有鑑於此，本創作的目的在提出一種非隔離型反驰式升壓轉換器，與傳統的升壓轉換器相比，可在相同的功率開關責任週期下獲得更高的電壓增益或輸出電壓。為達到上述目的或其它目的，本創作提出一種非隔離型反驰式升壓轉換器，用以驅動LED光源，LED光源具表單編號A0101 第4頁/共17頁 [0007] M411.067 有輸入端及輸出端。LED光源可應用於顯示裝置的背光源，顯示裝置例如為電腦螢幕（monitor)、電視機或一體機電腦（all-in-one computer)。非隔離型反馳式升壓轉換器包括具有儲能特性的變壓器、功率開關、二極體以及電容器，其中功率開關例如為場效電晶體。變壓器具有初級繞組及次級繞組，初級繞組及次級繞組均具有打點端及非打點端，初級繞組的打點端接收輸入電壓。功率開關具有第一端、第二端及控制端，功率開關的第一端搞接初級繞組的非打點端及次級繞組的打點端，功率開關的第二端耦接地端，功率開關的控制端接收控制信號，功率開關根據控制信號進行切換。二極體具有陽極端及陰極端，二極體的陽極端耦接次級繞組的非打點端。電容器具有第一端及第二端，電容器的第一端耦接二極體的陰極端並提供輸出電壓至LED光源的輸入端，電容器的第二端耦接地端。 [0008] 在一實施例中，輸入電壓由直流電源供應器提供。[0004] The controller 15 uses a Pulse-Width Modulation (PWM) controller coupled to the output of the LED light source 3 and the power switch Q1 of the boost converter 14 for receiving the LED light source. The output current of 3 is outputted, and the control signal CTL in the form of PWM is output according to the feedback voltage generated by the output current Im at its feedback end to control the duty cycle of the power switch Q1, thereby changing the output voltage Vy. The controller 15 further receives the enable signal EN and the dimming signal DIM, wherein the enable signal EN is used to determine whether the LED light source 3 is working, and the dimming signal DIM is used to determine the brightness of the LED light source 3. [0005] The conventional boost converter 14 is limited by the duty cycle Dd of the power switch Q1 and the physical characteristics of the component of the inductor L1 for energy storage, and cannot be highly voltage-operated in practical applications. Gain. When applied to a low voltage input, the conventional boost converter has a problem that the output voltage cannot be increased. When applied to high voltage output applications, it is often necessary to connect more than two conventional boost converters to provide high output voltage requirements, which will increase the cost of the design and the complexity of the circuit. [New content] [0006] In view of this, the purpose of this creation is to propose a non-isolated fly-back boost converter that can be obtained under the same power switching duty cycle as compared with the conventional boost converter. High voltage gain or output voltage. In order to achieve the above purpose or other purposes, the present application proposes a non-isolated fly-back type boost converter for driving an LED light source. The LED light source has a form number A0101. Page 4 of 17 [0007] M411.067 With input End and output. The LED light source can be applied to a backlight of a display device such as a computer monitor, a television, or an all-in-one computer. The non-isolated fly-back boost converter includes a transformer having a stored energy characteristic, a power switch, a diode, and a capacitor, wherein the power switch is, for example, a field effect transistor. The transformer has a primary winding and a secondary winding, and both the primary winding and the secondary winding have a striking end and a non-injecting end, and the striking end of the primary winding receives the input voltage. The power switch has a first end, a second end and a control end, and the first end of the power switch is connected to the non-doped end of the primary winding and the striking end of the secondary winding, and the second end of the power switch is coupled to the ground end, and the power switch is controlled The terminal receives the control signal, and the power switch switches according to the control signal. The diode has a male terminal and a cathode terminal, and the anode end of the diode is coupled to the non-doped end of the secondary winding. The capacitor has a first end and a second end. The first end of the capacitor is coupled to the cathode end of the diode and provides an output voltage to the input end of the LED light source, and the second end of the capacitor is coupled to the ground. In an embodiment, the input voltage is provided by a DC power supply.

直流電源供應器包括EMI濾波器、整流濾波器以及隔離型直流至直流轉換器，其中隔離型直流至直流轉換器例如為隔離型反馳式轉換器。EMI濾波器用以接收交流電源並滤除父流電源的電磁雜訊。整流渡波麵接Ε ΜI渡波* 用以將濾除電磁雜訊後的交流電源整流及濾波成直流電源。隔離型直流至直流轉換器耦接整流濾波器，用以接收直流電源並將直流電源轉換成輸入電壓。 [0009] 在一實施例中，控制信號由控制器提供，其中控制器例如為PWM控制器。控制器耦接LED光源的輸出端及功表單編號A0101 第5頁/共17頁 [0010] 率開關的控制端，控制器接收輸出電流並根據輸出電流提供控制信號。本創作因使用具有儲能特性的變壓H來取代傳統升壓轉換器中用於儲能的電感器，變壓器在功率開關導通時^順㈣量’在功率關截止時除了釋放先前健存卜還兼具匝數比增益效果而有電位提升效果，再搭配升壓轉換器本身的升壓倍率，因此可在相同的功率開關責任週期下獲得更高的電壓增益或輸出電壓，適合應用於低電壓輪人、高電壓輸出的場合。 [0011] 為讓本創作之上述和其他目的、特徵和優點能更明易隱下文特舉較佳實施例，並配合所附圖式，作詳細說明如下。【實施方式】 [0012] 圖2為採用本創作非隔離型反驰式升壓轉換器的㈣驅動電路方塊圖。請參照圖2，LED驅動電路2用以驅動 LED光源3，LED光源3具有輸入端及輸出端。led光源_ 如由多個發光二極體組成，這些發光二極趙串聯搞接於 LED光源3的輸人端及輸出端之間。⑽光源3可應用於如液晶顯示器等顯示裝置中作為背光源，顯示裝置例如為電腦螢幕、電視機或-趙機電腦等用途的顯示裝置。 [0013] LED驅動電路2包括EMI濾波器n、整流濾波器12、隔離型反驰式轉換器13、非隔離型反驰式㈣轉換器24 及控制器15，但並非用以限制本創作，例如隔離型反驰式轉換器13還可為其它隔離型直流至直流轉換器。謝滤表單编號A0101 # 6貢/共17頁波器11、整流濾波器12及隔離型反驰式轉換器13組成直流電源供應器以提供具有隔離特性的直流輸入電壓V ，各元件耦接關係及功能已於先前技術中描述，在此不再贅述。非隔離型反驰式升壓轉換器24耦接隔離型反驰式轉換器13，用以接收輸入電壓v並將輸入電壓v升壓 12 12 成輸出電壓V〇2以提供至LED光源3的輸入端。控制器15例如為PWM控制器’其耦接LED光源3的輸出端及非隔離型反驰式升壓轉換器24，用以接收LED光源3的輸出電流I ， 02 並根據輸出電流1〇2在其回饋端產生的回饋電壓輸出形式的控制信號CTL，以控制非隔離型反驰式升壓轉換器 24改變輸出電壓V〇2。控制器15另接收致能信號EN及調光信號DIM，其中致能信號EN用以決定LED光源3是否工作，調光信號DIM用以決定LED光源3的亮度。 [0014] 本創作非隔離型反驰式升壓轉換器24包括具有儲能特性的變壓器T1、功率開關Q2、二極體D2及電容器C2，其中功率開關Q2例如為場效電晶體。變壓器π具有初級繞組Np及次級繞組%，初級繞組及次級繞組n均具有打點端及非打點端，初級繞組Np的打點端接收輸入電壓 V! 2。功率開關Q2具有第一端、第二端及控制端，功率開關Q2的第一端耦接初級繞組Np的非打點端及次級繞組N 的打點端，功率開關Q2的第二端耦接地端，功率開關的的控制端耦接控制器15以接收控制信號CTL，功率開關Q2 根據控制信號CTL進行切換。二極體D2具有陽極端及陰極端，二極髅D2的陽極端轉接次級繞組%的非打點端。電容器C2具有第一端及第二端，電容器㈡的第—端耦接二表單編號A0101 第7頁/共17頁 [0015]M411067 極體D2的陰極端並提供輸出電壓至LED光源3的輸入端，電容器C2的第二端耦接地端。下面將推導本創作非隔離型反馳式升壓轉換器24的電壓增益，推導過程中忽略二極體D2的導通壓降。假設功率開關Q2的切換週期為T，在一個切換週期中的導通時間為丁训且截止時間為'a，即+ ，則功率開關 Q2的責任週期為DFB=T〇N/T。換言之，T〇N = DFBxT， [0016] 根據能量守怪及伏特-秒平衡（voltage-second b a 1 a n c e)定律，在一個工作週期内存入的能量總和必須等於釋放的能量總和，如此才能確保輸出不存在變異性。因此，在一個功率開關Q2的切換週期中，變壓器T1在導通時的磁通變化量及在截止時的磁通變化量是相等的，亦即： φ, =φ, (2) ^ON ^OFT- ^ y [0017] 當功率開關Q2導通時，可在變壓器T1的初級繞組Np 上產生壓降為 VNp =NPx^= VI2 (3) aon [0018] 當功率開關Q2截止時，可在變壓器T1的初級繞組Np 及次級繞組Ns上產生壓降為 VNp + VNs = (NP + Ns)x = V02 - VI2 (4) aoff 將（3)、（4)兩式代入（2)式中，可得到表單編號A0101 第8頁/共17頁 M411067The DC power supply includes an EMI filter, a rectification filter, and an isolated DC to DC converter, wherein the isolated DC to DC converter is, for example, an isolated flyback converter. The EMI filter is used to receive AC power and filter out electromagnetic noise from the parent current source. Rectifier wave surface interface ΜI wave* is used to rectify and filter the AC power source after filtering electromagnetic noise into DC power. The isolated DC-to-DC converter is coupled to a rectification filter for receiving DC power and converting the DC power to an input voltage. In an embodiment, the control signal is provided by a controller, such as a PWM controller. The controller is coupled to the output of the LED light source and the power of the form number A0101 Page 5 of 17 [0010] The control end of the rate switch, the controller receives the output current and provides a control signal according to the output current. This creation replaces the inductor used for energy storage in a conventional boost converter by using a transformer H with energy storage characteristics. When the power switch is turned on, the voltage is shun (four) quantity. It also has a turns ratio gain effect and a potential boosting effect, together with the boosting ratio of the boost converter itself, so that higher voltage gain or output voltage can be obtained under the same power switching duty cycle, which is suitable for low application. Voltage wheel people, high voltage output occasions. The above and other objects, features, and advantages of the present invention will become more apparent from the description of the appended claims. [Embodiment] [0012] FIG. 2 is a block diagram of a (four) driving circuit using the present non-isolated fly-back type boost converter. Referring to FIG. 2, the LED driving circuit 2 is used to drive the LED light source 3. The LED light source 3 has an input end and an output end. The led light source _ is composed of a plurality of light-emitting diodes, and these light-emitting diodes are connected in series between the input end and the output end of the LED light source 3. (10) The light source 3 can be applied to a display device such as a liquid crystal display as a backlight, and the display device is, for example, a display device for use in a computer screen, a television, or a camera computer. [0013] The LED driving circuit 2 includes an EMI filter n, a rectifying filter 12, an isolated flyback converter 13, a non-isolated fly-back type (four) converter 24, and a controller 15, but is not intended to limit the creation. For example, the isolated flyback converter 13 can also be other isolated DC to DC converters. Xie filter form number A0101 #6 tribute / total 17 page wave device 11, rectifier filter 12 and isolated flyback converter 13 constitute a DC power supply to provide DC input voltage V with isolation characteristics, each component is coupled Relationships and functions have been described in the prior art and will not be described again here. The non-isolated fly-up converter 24 is coupled to the isolated flyback converter 13 for receiving the input voltage v and boosting the input voltage v 12 12 into an output voltage V 〇 2 for providing to the LED light source 3 Input. The controller 15 is, for example, a PWM controller that is coupled to the output of the LED light source 3 and the non-isolated fly-back boost converter 24 for receiving the output current I, 02 of the LED light source 3 and according to the output current 1〇2 The control signal CTL in the form of a feedback voltage output generated at its feedback end controls the non-isolated fly-back type boost converter 24 to change the output voltage V〇2. The controller 15 further receives the enable signal EN and the dimming signal DIM, wherein the enable signal EN is used to determine whether the LED light source 3 operates, and the dimming signal DIM is used to determine the brightness of the LED light source 3. [0014] The present non-isolated fly-in boost converter 24 includes a transformer T1 having a stored energy characteristic, a power switch Q2, a diode D2, and a capacitor C2, wherein the power switch Q2 is, for example, a field effect transistor. The transformer π has a primary winding Np and a secondary winding %, and both the primary winding and the secondary winding n have a striking end and a non-injecting end, and the striking end of the primary winding Np receives the input voltage V! The power switch Q2 has a first end, a second end and a control end. The first end of the power switch Q2 is coupled to the non-tapping end of the primary winding Np and the striking end of the secondary winding N, and the second end of the power switch Q2 is coupled to the ground end. The control end of the power switch is coupled to the controller 15 to receive the control signal CTL, and the power switch Q2 is switched according to the control signal CTL. The diode D2 has an anode end and a cathode end, and the anode end of the diode D2 is switched to the non-doped end of the secondary winding %. The capacitor C2 has a first end and a second end, and the first end of the capacitor (2) is coupled to the cathode terminal of the form body A0101, page 7 / page 17 [0015] M411067 body D2 and provides an output voltage to the input of the LED light source 3 The second end of the capacitor C2 is coupled to the ground. The voltage gain of the non-isolated fly-up converter 24 of the present invention will be derived below, and the turn-on voltage drop of the diode D2 is ignored during the derivation. Assuming that the switching period of the power switch Q2 is T, the conduction time in one switching period is D and the cut-off time is 'a, that is, +, then the duty cycle of the power switch Q2 is DFB=T〇N/T. In other words, T〇N = DFBxT, [0016] According to the law of energy and voltage-second ba ance, the sum of the energy stored in one working cycle must be equal to the sum of the released energy, so as to ensure the output. There is no variability. Therefore, in the switching period of one power switch Q2, the amount of change in the magnetic flux when the transformer T1 is turned on and the amount of change in the flux at the time of turning off are equal, that is, φ, =φ, (2) ^ON ^OFT - ^ y [0017] When the power switch Q2 is turned on, a voltage drop can be generated on the primary winding Np of the transformer T1 to be VNp = NPx^= VI2 (3) aon [0018] When the power switch Q2 is turned off, it can be in the transformer T1 The voltage drop across the primary winding Np and the secondary winding Ns is VNp + VNs = (NP + Ns)x = V02 - VI2 (4) aoff Substituting (3) and (4) into equation (2) Get Form Number A0101 Page 8 of 17 M411067

Yn^J〇E. = (VQ2 ~ Vt^xT^Yn^J〇E. = (VQ2 ~ Vt^xT^

Np Np +NS 再將Ton=DfbxT、T〇FF = (1-DFB)xT代入上式，整理可得本創作非隔離型反驰式升壓轉換器24的電壓增益為 ⑶ [0019] 比較（1)、（5)兩式，可知在相同的功率開關責任週期（Db = Dfb = D)條件下，本創作非隔離型反馳式升壓轉換器24的電壓增益為傳統升壓轉換器丨4的電壓增益的（1+D xNs/Np)倍，因此非隔離型反驰式升壓轉換器24可在相同的功率開關責任週期下獲得更高的電壓增益或輸出電壓 [0020] 從另一個觀點來看，本創作非隔離型反馳式升壓轉換器24使用具有儲能特性的變壓器T1取代傳統升壓轉換Np Np +NS then substitutes Ton=DfbxT, T〇FF = (1-DFB)xT into the above equation, and the voltage gain of the non-isolated fly-type boost converter 24 can be obtained as (3) [0019] 1), (5), it can be seen that under the same power switch duty cycle (Db = Dfb = D), the voltage gain of the non-isolated fly-type boost converter 24 is a conventional boost converter. The voltage gain of 4 is (1+D xNs/Np) times, so the non-isolated fly-back boost converter 24 can achieve higher voltage gain or output voltage under the same power switching duty cycle [0020] From a point of view, the present non-isolated fly-up converter 24 replaces the traditional boost converter with a transformer T1 with energy storage characteristics.

器14中用於儲能的電感器L1，變壓1T1在功率開關的導通時儲存順向能量，在功率開關Q2裁止時除了釋放先前儲存的能量外，還兼具阻數比增益效果（即Dx(Ns/Np))而有電位提升效果，再搭配升壓轉換器本身的升壓S倍率（即 "(l-D))，因此可在相同的功率開關責任週期下獲得更高的電壓增益或輸出電屋。 [0021] 12 II 第9頁/共17頁圖3為圖1所示傳統升麼轉換器14及圖2所示本創作非隔離型反馳式升㈣換n24在相同輸人電壓下的輸出電愿特性曲線圖《•請參照圖3，此特性曲線圖為⑴、（5)兩式在相同的輸入電虔(Vv v & 2 表單編號 M411067 =2)之條件下所繪製而成。從圖3可清楚看出，在相同的功率開關貴任週期下，本創作非隔離型反驰式升壓轉換器24的輸出電壓VQ2高於傳統升壓轉換器14的輸出電廢 Voi。 [0022] [0023] [0024] [0025] [0026] 綜上所述，本創作因使用具有儲能特性的變壓器來取代傳統升壓轉換器中用於儲能的電感器，變壓器在功率開關導通時儲存順向能量，在功率開關截止時除了釋放先前儲存的能量外，還兼具匝數比增益效果而有電位提升效果，再搭配升壓轉換器本身的升壓倍率，因此可在相同的功率開關責任週期下獲得更高的電壓增益或輸出電壓，適合應用於低電壓輸入、高電壓輸出的場合。雖然本創作已以較佳實施例揭露如上，然其並非用於限定本創作，任何熟習此技藝者，在不脫離本創作之精神和範圍内，當可作些許之更動與潤飾，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】圖1為一種採用傳統升壓轉換器的LED驅動電路方塊圖。圖2為採用本創作非隔離型反馳式升壓轉換器的led 驅動電路方塊圖。圖3為圖1所示傳統升壓轉換器及圖2所示本創作非隔離型反馳式升壓轉換器在相同輸入電壓下的輸出電壓特性曲線圖。【主要元件符號說明】表單編號A0101 第10頁/共17頁 M411067 [0027] [0028] [0029] [0030] [0031] [0032] [0033]In the inductor L1 for storing energy in the device 14, the transformer 1T1 stores the forward energy when the power switch is turned on, and in addition to releasing the previously stored energy when the power switch Q2 is cut, it also has the resistance ratio gain effect ( That is, Dx(Ns/Np)) has a potential boosting effect, and is matched with the boost S-rate of the boost converter itself (ie, "(lD)), so that a higher voltage can be obtained under the same power switching duty cycle. Gain or output electricity house. [0021] 12 II Page 9 of 17 Figure 3 is the output of the conventional converter 14 shown in Figure 1 and the output of the non-isolated reverse-speed (four) for n24 shown in Figure 2 at the same input voltage. Electric power characteristic graph "•Please refer to Figure 3, this characteristic graph is drawn under the conditions of the same input power (Vv v & 2 form number M411067 = 2). As is clear from Fig. 3, the output voltage VQ2 of the present non-isolated fly-type boost converter 24 is higher than the output power waste Voi of the conventional boost converter 14 under the same power switch duty cycle. [0022] [0025] In summary, the present invention replaces the inductor for energy storage in a conventional boost converter by using a transformer having energy storage characteristics, and the transformer is in the power switch. When the power switch is turned off, the forward energy is stored. When the power switch is turned off, in addition to releasing the previously stored energy, it also has a turns ratio gain effect and a potential boosting effect, and is matched with the boosting ratio of the boost converter itself, so that it can be the same. The power switch has a higher voltage gain or output voltage under the duty cycle, which is suitable for low voltage input and high voltage output. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention, and anyone skilled in the art can make some 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. [Simple diagram of the diagram] Figure 1 is a block diagram of an LED driver circuit using a conventional boost converter. FIG. 2 is a block diagram of a led driving circuit using the non-isolated fly-back type boost converter of the present invention. 3 is a graph showing output voltage characteristics of the conventional boost converter shown in FIG. 1 and the inventive non-isolated fly-back boost converter shown in FIG. 2 at the same input voltage. [Description of Main Component Symbols] Form No. A0101 Page 10 of 17 M411067 [0027] [0030] [0033] [0033]

[0034] [0035] [0036] [0037] [0038] [0039][0039] [0039] [0039]

[0040] [0041] [0042] [0043] [0044] [0045] 1、2 : LED驅動電路 11 : EMI濾波器 12 :整流濾波器 13 :隔離型反驰式轉換器 14 :升壓轉換器 15 :控制器 24 :非隔離型反馳式升壓轉換器 3 : L E D光源 Cl、C2 :電容器 Dl、D2 :二極體 L1 :電感器 Ql、Q2 :功率開關 T1 :變壓器 Np :初級繞組 Ns :次級繞組 k、I‘輸出電流 Va :交流電源 AC vDe :直流電源 νπ、VI2 :輸入電壓表單編號A0101 第11頁/共17頁 M411067 [0046] V01 [0047] CTL [0048] DIM [0049] ΕΝ : :輸出電壓 :控制信號 :調光信號致能信號表單編號A0101 第12頁/共17頁[0045] [0045] [0045] 1, 2: LED drive circuit 11: EMI filter 12: rectifier filter 13: isolated flyback converter 14: boost converter 15 : Controller 24 : Non-isolated fly-back boost converter 3 : LED light source Cl, C2 : Capacitor Dl, D2 : Diode L1 : Inductor Ql , Q2 : Power switch T1 : Transformer Np : Primary winding Ns : Secondary winding k, I' Output current Va : AC power supply AC vDe : DC power supply νπ, VI2 : Input voltage Form No. A0101 Page 11 / Total 17 pages M411067 [0046] V01 [0047] CTL [0048] DIM [0049] ] ΕΝ : : Output voltage: Control signal: Dimming signal enable signal Form No. A0101 Page 12 of 17

Claims

M411067 六、申請專利範圍： 1 . 一種非隔離型反馳式升壓轉換器，用以驅動一發光二極體光源，該發光二極體光源具有一輸入端及一輸出端，該非隔離型反驰式升壓轉換器包括：一變壓器，具有一初級繞組及一次級繞組，該初級繞組及該次級繞組均具有一打點端及一非打點端，該初級繞組的打點端接收一輸入電壓；一功率開關，具有一第一端'一第二端及一控制端，該功率開關的第一端耦接該初級繞組的非打點端及該次級繞組的打點端，該功率開關的第二端耦接一地端，該功率開關的控制端接收一控制信號，該功率開關根據該控制信號進行切換；一二極體，具有一陽極端及一陰極端，該二極體的陽極端耗接該次級繞組的非打點端；以及一電容器，具有一第一端及一第二端，該電容器的第一端耦接該二極體的陰極端並提供一輸出電壓至該發光二極體光源的輸入端，該電容器的第二端耦接該地端。 2 .如申請專利範圍第1項所述之非隔離型反馳式升壓轉換器，其中，該輸入電壓由一直流電源供應器提供，該直流電源供應器包括：一電磁干擾濾波器，用以接收一交流電源並濾除該交流電源的電磁雜訊；一整流濾波器，耦接該電磁干擾濾波器，用以將濾除電磁雜訊後的該交流電源整流及濾波成一直流電源；以及一隔離型直流至直流轉換器，耦接該整流濾波器，用以接 100206875 表單編號A0101 第13頁/共17頁 1002022741-0 M411067 收該直流電源並將該直流電源轉換成該輸入電壓。 3 .如申請專利範圍第2項所述之非隔離型反馳式升壓轉換器，其中，該隔離型直流至直流轉換器為一隔離型反驰式轉換器。 4 .如申請專利範圍第1項所述之非隔離型反驰式升壓轉換器，其中，該控制信號由一控制器提供，該控制器耦接該發光二極體光源的輸出端及該功率開關的控制端，該控制器接收該輸出電流並根據該輸出電流提供該控制信號。 5 .如申請專利範圍第4項所述之非隔離型反馳式升壓轉換器，其中，該控制器為一脈寬調變控制器。 6 .如申請專利範圍第1項所述之非隔離型反驰式升壓轉換器，其中，該功率開關為一場效電晶體。 7 .如申請專利範圍第1項所述之非隔離型反驰式升壓轉換器，其中，該發光二極體光源應用於一顯示裝置的一背光源〇 8 .如申請專利範圍第7項所述之非隔離型反馳式升壓轉換器，其中，該顯示裝置為一電腦螢幕、一電視機或——體機電腦。 100206875 表單編號A0101 第14頁/共17頁 1002022741-0M411067 VI. Patent application scope: 1. A non-isolated reverse-type boost converter for driving a light-emitting diode light source, the light-emitting diode light source has an input end and an output end, and the non-isolated type reverse The step-up converter includes: a transformer having a primary winding and a primary winding, the primary winding and the secondary winding each having a punctual end and a non-tapping end, the punctual end of the primary winding receiving an input voltage; a power switch having a first end 'a second end and a control end, the first end of the power switch being coupled to the non-tapping end of the primary winding and the striking end of the secondary winding, the second of the power switch The control end of the power switch receives a control signal, and the power switch switches according to the control signal; a diode has an anode end and a cathode end, and the anode end of the diode is consumed a non-tapping end of the secondary winding; and a capacitor having a first end and a second end, the first end of the capacitor being coupled to the cathode end of the diode and providing an output voltage to Input terminal of the light emitting diode light source, the second terminal of which is coupled to the ground terminal. 2. The non-isolated fly-back boost converter of claim 1, wherein the input voltage is provided by a DC power supply, the DC power supply comprising: an electromagnetic interference filter, Receiving an AC power source and filtering electromagnetic noise of the AC power source; a rectifying filter coupled to the electromagnetic interference filter for rectifying and filtering the AC power source after filtering electromagnetic noise into a DC power source; An isolated DC-to-DC converter coupled to the rectifier filter for receiving 100206875 Form No. A0101 Page 13 of 17 1002022741-0 M411067 receives the DC power and converts the DC power to the input voltage. 3. The non-isolated fly-back boost converter of claim 2, wherein the isolated DC-to-DC converter is an isolated flyback converter. 4. The non-isolated fly-back type boost converter according to claim 1, wherein the control signal is provided by a controller coupled to the output end of the light emitting diode light source and the A control terminal of the power switch, the controller receives the output current and provides the control signal based on the output current. 5. The non-isolated fly-back boost converter of claim 4, wherein the controller is a pulse width modulation controller. 6. The non-isolated fly-back boost converter of claim 1, wherein the power switch is a field effect transistor. 7. The non-isolated fly-back type boost converter according to claim 1, wherein the light-emitting diode light source is applied to a backlight 〇8 of a display device. The non-isolated fly-back type boost converter, wherein the display device is a computer screen, a television set or a body computer. 100206875 Form No. A0101 Page 14 of 17 1002022741-0