TWM441132U - Liquid crystal display product and flyback power conversion device thereof - Google Patents
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M441132 五、新型說明： 【新型所屬之技術領域】 本新型是有關於一種產品及裝置，特別是指一種液晶 顯示產品及其反激式電源轉換裝置。 【先前技術】 現有中小尺寸的液晶顯示產品所使用的電源，基本採 用反激式開關電源，反激式開關電源具有設計成本低、產 品架構穩定的優點，但其因採用肖特基二極體做輸出整流 而使電源轉換效率通常較低，現有輸出功率小於75W以内馨 的液晶顯示產品所採用的反激式開關電源通常具有一第一 輸出鈿及一第一輸出端，且該第一輸出端是提供一 5V直流 電壓’該第二輸出端是提供一 16V直流電壓。 該5V直流電壓用以提供給該液晶顯示產品内部用以處 理影像的一主基板電路（Main board circuit);該16V直流 電壓用以提供給該液晶顯示產品的二極體燈管的一驅動電 路0 該反激式開關電源的第一及第二輸出端的兩電流n、I2 _ 會隨著負載增加而增加，例如：該反激式開關電源應用於 22忖的液晶顯示產品時，該兩個f流分別為ii=2a及 12=1 A，則此時該反激式開關電源的轉換效率通常只有 82〇/〇〜85%;若同樣的該反激式開關電源應用於24 β寸的液晶 顯示產品時，該兩個電流η、12則分別增加為η=3 5Α及 Ι2=1.5Α，則此時該轉換效率通常降低為78%〜。 目前市面上的液晶顯示器產品’特別是銷售全球地區 4 M441132 的液晶顯示器產品，其整機在能效方面通常需要滿足美國 能源之星# EPA5.1標準，即不同尺寸、圖元的液晶顯示器 產品其整機的一功率消耗上限都有被規範，尤其到了 2〇13 年的第二季之後，這些銷售全球的液晶顯示器產品還必須 滿足美國能源之星的EPA6.0新標準，且EPA6.0標準相較 目前的EPA5.1標準對於功率消耗上限的規範將更嚴格這 意味著到時應用於該等多功能的液晶顯示產品的電源就需 要有更高的電源轉換效率。 目刖反激式開關電源的工作模式可分為連續電流模式 (continues inductor current mode, CCM)和不連續電流模 式（discontinues inductor current mode，DCM)兩種，且工 作在連續電流模式時的電源其整體轉換效率較工作在不連 續電流模式時來得高，i文電源工程師在設計應用於大尺时 的液晶顯示產品的反激式開關電源時，通常希望能設計在 連續電流模式。 而目剛反激式開關電源的大約有4〇%左右的功耗來自 用以次級側輸出整流的一肖特基二極體所以現今的電源 工程師已經開始嘗試使用一金氧半場效電晶體來取代該肖 特基一極體（即通常所說的同步整流技術），以降低功耗而 提升電源轉換效率》 現今反激式開關電源的同步整流技術主要有自驅式同 步整流技術和採用控制晶片控制的同步整流技術，但目前 不s疋電源工程師自已開發設計出來的自驅式同步整流技 術還是由晶片設計工程師開發出來的同步整流技術，一般 5 M441132 都只適合工作在不連續電流模式，而較難適合工作在連續 電流模式，即便目前有些控制晶片廠家聲稱新設計出來的 同步整流控制晶片可工作在連續及不連續電流模式，但實 際工作在連續電流模式時仍然會因該同步整流控制晶片需 要一反應時間而仍存在電流倒灌的問題。 上述該同步整流控制晶片工作在連續電流模式時，由 於該同步整流控制晶片從偵測到一用來做次級側同步整流 的金氧半場效電晶體漏極端的一關斷信號，到根據該關斷 信號輸出一關斷控制信號給該同步整流的金氧半場效電晶鲁 體的一控制端的過程令存在一定反應時間，使得該變壓器 的一次級側繞組容易形成電流倒灌問題，進而使得該同步 整流的金氧半場效電晶體在關斷之時，產生一施加於該同 V整"’L的金氧半％效電晶體的沒極與源極的尖峰電壓，且 該尖峰電壓很可能擊穿該同步整流金氧半場效電晶體的汲 極與源極，針對此問題，目前電源工程師只能採用具有較 高耐壓規格的金氧半場效電晶體作為同步整流之用但缺 點在於具有越高耐壓規格的金氧半場效電晶體就越昂貴。_ 此外，目前市面上的同步整流控制晶片因沒有普遍得 到應用所以價格往往較高，但液晶顯示器產品的市場價格 卻逐年下降’所以該液晶顯示器產品若採用該種具有同步 整流控制晶片的電源將不具市場競爭優勢。 【新型内容】 因此’本新型之-目的’即在提供一種可以解決上述 缺點的液晶顯示產品。 6 M441132 於是，本新型液晶顯示產品，包含一液晶螢幕及一反 激式電源轉換裝置。 該液晶螢幕用於顯示畫面並接收一呈直流的輸出電壓 以作為電力來源。 該反激式電源轉換裝置可以工作於連續及不連續電流 模式’並包括一整流濾波模組、一變壓器、一初級側開關 電路、一第一輸出據波電路、一次級側開關電路及一電位 極性偵測電路。 該整流濾波模組用以接收一交流電壓，並將該交流電 壓進行整流濾波以得到一呈直流的濾波電壓。 β亥變壓器具有一初級側繞組、一第一次級側繞組及一 次級側偵測繞組，每一繞組具有一打點端及一非打點端， 該初級側繞組的非打點端電連接於該整流濾波模組以接收 該濾波電壓。 該初級侧開關電路電連接於一初級側接地與該初級側 繞組的打點端之間，且根據一脈波信號控制以在導通與不 導通間切換’以對應地改變該初級側繞組的二端的電位極 性，而使該第一次級側繞組與該次級側偵測繞組的二端的 電位極性對應改變’且於該第一次級側繞組產生一呈交流 的感應電壓。 該第一輸出濾波電路電連接於該第一次級側繞組以接 收該感應電壓，並進行;慮波以得到該第一輸出電廢。 該次級侧開關電路電連接於該第一輸出濾波電路與該 第一次級侧繞組之間，且受控制切換於導通與不導通之 7 M441132 間，以提供或中斷該第一輸出濾波電路與該第一次級側繞 組之間的電流傳遞路徑。 該電位極性偵測電路電連接於該次級侧偵測繞組與該 次級側開關電路之間，並根據該次級側偵測繞組的二端的 電位極性來偵測該初級側開關電路是否導通，以決定是否 將該次級側開關電路設定成不導通。 更詳細地說明’該電位極性偵測電路是在偵測到該初 級側開關電路導通時’將該次級侧開關電路設定成不導 通0 而本新型之另一目的，即在提供一種可以解決上述缺 點的反激式電源轉換裝置。 δ亥反激式電源轉換裝置，包括一整流滤波模組、一變 壓器、一初級側開關電路、一第一輸出濾波電路、一次級 側開關電路及一電位極性偵測電路。 該整流濾波模組用以接收一交流電壓，並將該交流電 壓進行整流濾波以得到一呈直流的濾波電壓。 該變壓器具有一初級側繞組、一第一次級側繞組及一 次級侧偵測繞組，每一繞組具有一打點端及一非打點端， 該初級側繞組的非打點端電連接於該整流濾波模組以接收 該濾波電壓。 該初級侧開關電路電連接於一初級側接地與該初級側 繞組的打點端之間，且根據一脈波信號控制以在導通與不 導通間切換，以對應地改變該初級侧繞組的二端的電位極 性，而使該第一次級側繞組與該次級側偵測繞組的二端的 8 M441132 電位極性對應改變，且於該第—次級㈣組產生—呈交流 的感應電壓。 該第一輸出濾波電路電連接於該第一次級側繞組以接 收該感應電I，並進行m得龍第-輸出電壓。 該次級側開關電路電連接於該第一輸出渡波電路與該 第一次級側繞組之間，且受控制切換於導通與不導通之 間，以提供或中斷該第一輸出遽波電路與該第一次級側繞 組之間的電流傳遞路徑。 該電位極性偵測電路電連接於該次級側偵測繞組與該 次級侧開關m，並根據該线側偵職組的二端的 電位極性來偵測該初級侧開關電路是否導通，以決定是否 將該次級側開關電路設定成不導通。 更詳細地說明，該電位極性偵測電路是在谓測到該初 級侧開關電路導通時，將該次級侧開關電路設定成不導 通。 【實施方式】 有關本新型之前述及其他技術内容、特點與功效，在 以下配合參考圖式之二個較佳實施例的詳細說明中將可 清楚的呈現》 在本新型被詳細描述之前，要注意的是，在以下的說 明内容中，類似的元件是以相同的編號來表示。 參閱圖1，本新型液晶顯示產品之第一較佳實施例包含 -液晶螢I 1及-具有同步整流功能且可王作在連續及不 連續電流模式的反激式電轉換裝置100。 9 M441132 該液晶螢幕1用於顯示畫面並接收一呈直流的第一輸 出電壓以作為電力來源。 該反激式電源轉換裝置100包括一整流濾波模組3、一 變壓器4、一初級側開關電路5、一第一輸出濾波電路6、 一次級侧開關電路7、電位極性偵測電路8及一次級侧電流 偵測電路9。 该整流濾波模組3用以接收一交流電壓，並將該交流 電壓進行整流渡波以得到一呈直流的遽波電壓。更詳細的 說明，該整流濾波模組3具有一 EMI濾波電路3 1及一橋式· 整流及工頻濾波電路32 ^該EMI濾波電路31用以接收來 自外界一電網（圖未示）的一交流電壓，並對該交流電壓 進行濾波以產生一輸出’且該反激式電源轉換裝置1〇〇利 用自身的該EMI濾波電路31避免將自身所產生的一高頻雜 訊幹擾該電網，也避免被來自該電網的一高頻雜訊所幹 擾。該橋式整流及工頻濾波電路32電連接該EMI濾波電路 31以接收該輸出，並將所接收到的該輸出進行全波整流及 電容濾波後產生具有一定電壓波紋的該濾波電壓。 · 該變壓器4具有一初級側繞組Np、一第一次級侧繞組 Ns及一次級側偵測繞組Ndet。每一繞組Np、Ns、具 有一打點端及一非打點端，且該初級側繞組Np的打點端、 該第一次級侧繞組Ns的打點端及該次級側偵測繞組Ndet 的打點端具有相同的電位極性，該等繞阻Np、Ns、Ndet的 非打點端也具有相同的電位極性並與該等打點端的電位極 性相反。該初級侧繞組Np的非打點端電連接於該橋式整流 10 M441132 及工頻濾波電路32以接收該濾波電壓。 該初級側開關電路5電連接於一初級側接地GND1與 該初級側繞組Np的打點端之間，且根據一脈波信號控制以 在導通與不導通間切換，以對應地改變該初級側繞組NP的 二端的電位極性’而使該第一次級側繞組Ns與該次級侧偵 測繞組Ndet的二端的電位極性對應改變，而於該第一次級 側繞組Ns產生一呈交流的感應電壓。 該初級侧開關電路5具有一初級侧開關51及一電阻 52。該初級側開關51具有一電連接該初級侧繞組Np的打 點端的第一端、一第二端，及一接收該脈波信號的控制 端。該電阻52具有一電連接該初級側開關η的第二端的 第一端，及一電連接該初級側接地GND1的第二端。該電 阻52主要作用是採樣流過該初級側開關51的第二端的一 開關電流，並利用該開關電流於自身的第一端產生一回饋 到一調變控制晶片（圖未示）的初級回饋電壓該調變控 制晶片還採樣該變壓器4的第一次級側繞組Ns的打點及非 打點端的一個次級側輸出電壓，並根據該次級側輸出電壓 經採樣回饋給該調變控制晶片的次級回饋電壓與該初級回 饋電壓進行比較的結果調整該調變控制晶片所輸出的該脈 波k號的一責任導通比（duty )，以使相對應的反激式電源 轉換裝置100輸出穩定直流的第一輸出電壓。 在該第一較佳實施例中，該初級侧開關51是N型金氧 半場效電晶體（MOSFET)，且第一端是汲極（drain)，第二 端是源極（source)，控制端是閘極（gate)。 11 該第-輸出渡波電路6電連接於該第一 以接收該錢電壓，並進行較Μ到直流㈣ 電壓。該第—輸出濾波電路6具有-第-電感61、一=出 電容62及一第二電容63。 , „ ^ a 第— 該第一電感61具有一電遠 級側繞組Ns的打點端的第一端， 接-人 62具有一電連接該第一電 一。以一電容 电迚丧^電感61的第一端的第一端，及 連接該次級側接地GND2的第u第二電容63 = 電連接該第一電感61的第二端的第-端，及-電連接 級側接地G臟的第二端，且該第二電容63的第一端：： 該第一輸出電壓。 該次級側開關電路7電連接於該第一輸出濾波電路6 與該第-次級側繞組Ns之間，且受控制切換於導通與不導 通之間，以提供或中斷該第一輸出濾波電路6與該第一次 級側繞組Ns之間的電流傳遞路徑。 该次級側開關電路7具有一第一整流電晶體71，該第 一整流電晶體71具有一電連接該第一次級側繞組Ns的非 打點端的第一端、一電連接該次級側接地GND2的第二 % ’及—控制端。在該第一較佳實施例中，該第一整流電 晶體71是N型金氧半場效電晶體，且第一端是汲極，第二 端是源極，控制端是閘極。 該電位極性偵測電路8電連接於該次級側偵測繞組 Ndet與該次級側開關電路7之間，並根據該次級側偵測繞 組Ndet的二端的電位極性來偵測該初級側開關電路（5)是否 導通’以決定是否將該次級側開關電路7設定成不導通° 12 M441132 更評細地說 側開關電路（5)導通時，將兮4級二*" 〇疋 初級 吁將。亥-人級側開關電路7設定成不導 通。該電位極性偵測電路8具有―_電晶體Η、—電阻 82及一齊納二極體83。 該4貞測電晶體81具有一雷造社从斗松 八男電連接於該第一整流電晶體71 的控制端的第一端、—電連接該次級側接地GND2的第二M441132 V. New description: [New technical field] The present invention relates to a product and device, in particular to a liquid crystal display product and a flyback power conversion device thereof. [Prior Art] The power supply used in the small and medium-sized liquid crystal display products basically adopts a flyback switching power supply. The flyback switching power supply has the advantages of low design cost and stable product architecture, but it adopts a Schottky diode. The output rectification makes the power conversion efficiency generally low. The flyback switching power supply used in the existing liquid crystal display products with an output power less than 75 W usually has a first output port and a first output terminal, and the first output is The terminal is supplied with a 5V DC voltage. The second output terminal provides a 16V DC voltage. The 5V DC voltage is used to provide a main board circuit for processing images in the liquid crystal display product; the 16V DC voltage is used to provide a driving circuit for the diode lamp of the liquid crystal display product. 0 The two currents n and I2 _ of the first and second output terminals of the flyback switching power supply increase as the load increases. For example, when the flyback switching power supply is applied to a 22-inch liquid crystal display product, the two The f-flow is ii=2a and 12=1A respectively, then the conversion efficiency of the flyback switching power supply is usually only 82〇/〇~85%; if the same flyback switching power supply is applied to the 24β inch In the liquid crystal display product, the two currents η and 12 are respectively increased to η=3 5Α and Ι2=1.5Α, and the conversion efficiency is usually reduced to 78%~. Currently, liquid crystal display products on the market 'especially sell liquid crystal display products of 4 M441132 in the world. The whole machine needs to meet the US Energy Star # EPA5.1 standard in terms of energy efficiency, that is, liquid crystal display products of different sizes and primitives. The upper limit of the power consumption of the whole machine has been regulated, especially after the second quarter of 2002. These global LCD products must also meet the new EPA6.0 standard of the US Energy Star, and the EPA6.0 standard. Compared with the current EPA 5.1 standard, the specification of the upper limit of power consumption will be stricter, which means that the power supply applied to these multifunctional liquid crystal display products needs higher power conversion efficiency. The operating mode of the flyback switching power supply can be divided into two types: continuous inductor mode (CCM) and discontinuous inductor mode (DCM), and the power supply operates in continuous current mode. The overall conversion efficiency is higher than when working in the discontinuous current mode. When designing a flyback switching power supply for liquid crystal display products used in large scales, it is usually desirable to design in continuous current mode. About 4% of the power of the flyback switching power supply comes from a Schottky diode used for secondary side output rectification. So today's power engineers have begun to try a gold oxide half field effect transistor. To replace the Schottky one-pole (known as synchronous rectification technology) to reduce power consumption and improve power conversion efficiency. The synchronous rectification technology of today's flyback switching power supply mainly has self-driven synchronous rectification technology and adoption. Synchronous rectification technology for controlling wafer control, but at present, the self-driven synchronous rectification technology developed and designed by the power supply engineer is also a synchronous rectification technology developed by the chip design engineer. Generally, the 5 M441132 is only suitable for working in the discontinuous current mode. It is more difficult to work in continuous current mode. Even though some control chip manufacturers claim that the newly designed synchronous rectification control chip can work in continuous and discontinuous current mode, the actual operation in continuous current mode will still be due to the synchronous rectification. Controlling the wafer requires a reaction time while still having the problem of current backflow. When the synchronous rectification control chip is operated in the continuous current mode, the synchronous rectification control chip detects a turn-off signal from the drain terminal of the MOS half-effect transistor used for the secondary side synchronous rectification, according to the The process of turning off the signal output and turning off the control signal to a control terminal of the synchronously rectified metal oxide half field effect crystal body has a certain reaction time, so that the primary side winding of the transformer is easy to form a current backflow problem, thereby making the The synchronous rectification of the gold-oxygen half-field effect transistor generates a spike voltage of the gate and the source of the gold-oxygen half-effect transistor applied to the same V<'L, and the peak voltage is very high. It is possible to break down the drain and source of the synchronous rectification MOS field-effect transistor. For this problem, power supply engineers can only use the MOS field-effect transistor with higher withstand voltage specifications for synchronous rectification. The more expensive the gold oxide half field effect transistor with higher withstand voltage specifications. _ In addition, the current synchronous rectification control chips on the market are often expensive because they are not widely used, but the market price of liquid crystal display products has been decreasing year by year. Therefore, if the liquid crystal display product adopts the power supply with the synchronous rectification control chip, Does not have a competitive advantage in the market. [New content] Therefore, the present invention aims to provide a liquid crystal display product which can solve the above disadvantages. 6 M441132 Thus, the novel liquid crystal display product comprises a liquid crystal screen and a flyback power conversion device. The LCD screen is used to display a picture and receive a DC output voltage as a source of power. The flyback power conversion device can operate in a continuous and discontinuous current mode' and includes a rectifying filter module, a transformer, a primary side switching circuit, a first output data circuit, a primary side switching circuit, and a potential Polarity detection circuit. The rectifying filter module is configured to receive an alternating current voltage and rectify and filter the alternating current voltage to obtain a DC filtered voltage. The β-hai transformer has a primary side winding, a first secondary side winding and a primary side detection winding, each winding has a dot end and a non-doping end, and the non-doped end of the primary side winding is electrically connected to the rectification The filter module receives the filtered voltage. The primary side switch circuit is electrically connected between a primary side ground and a dot end of the primary side winding, and is controlled according to a pulse signal to switch between conducting and non-conducting to correspondingly change the two ends of the primary side winding. The polarity of the potential changes such that the polarity of the potential of the first secondary side winding and the second side of the secondary side detecting winding change and generates an induced voltage of alternating current in the first secondary side winding. The first output filter circuit is electrically connected to the first secondary side winding to receive the induced voltage, and is performed; the wave is waved to obtain the first output power waste. The secondary side switching circuit is electrically connected between the first output filter circuit and the first secondary side winding, and is controlled to be switched between the conduction and non-conduction 7 M441132 to provide or interrupt the first output filter circuit. A current transfer path between the first secondary side winding. The potential polarity detecting circuit is electrically connected between the secondary side detecting winding and the secondary side switching circuit, and detects whether the primary side switching circuit is turned on according to the polarity of the potential of the two ends of the secondary side detecting winding. To determine whether to set the secondary side switching circuit to be non-conductive. Explain in more detail that 'the potential polarity detecting circuit is configured to set the secondary side switching circuit to be non-conducting 0 when detecting the conduction of the primary side switching circuit, and another object of the present invention is to provide a solution A flyback power conversion device of the above disadvantages. The delta-hai flyback power conversion device comprises a rectifying filter module, a transformer, a primary side switching circuit, a first output filtering circuit, a primary-stage side switching circuit and a potential polarity detecting circuit. The rectifying filter module is configured to receive an alternating current voltage and rectify and filter the alternating current voltage to obtain a DC filtered voltage. The transformer has a primary side winding, a first secondary side winding and a primary side detection winding, each winding has a dot end and a non-doping end, and the non-doped end of the primary side winding is electrically connected to the rectification filter The module receives the filtered voltage. The primary side switch circuit is electrically connected between a primary side ground and a dot end of the primary side winding, and is controlled according to a pulse signal to switch between conduction and non-conduction to correspondingly change the two ends of the primary side winding. The potential polarity is such that the polarity of the potential of the first secondary side winding and the 8 M441132 of the two ends of the secondary side detecting winding are changed, and the induced voltage of the alternating current is generated in the first (second) group. The first output filter circuit is electrically connected to the first secondary side winding to receive the induced current I, and performs a m-dragon-output voltage. The secondary side switching circuit is electrically connected between the first output wave circuit and the first secondary side winding, and is controlled to be switched between conducting and non-conducting to provide or interrupt the first output chopper circuit and A current transfer path between the first secondary side windings. The potential polarity detecting circuit is electrically connected to the secondary side detecting winding and the secondary side switch m, and detects whether the primary side switching circuit is turned on according to the potential polarity of the two ends of the line side Detective Group to determine whether the primary side switching circuit is turned on. Whether to set the secondary side switching circuit to be non-conductive. More specifically, the potential polarity detecting circuit sets the secondary side switching circuit to be non-conductive when it is detected that the primary side switching circuit is turned on. [Embodiment] The foregoing and other technical contents, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the accompanying drawings. Note that, in the following description, like elements are denoted by the same reference numerals. Referring to Fig. 1, a first preferred embodiment of the novel liquid crystal display product comprises a liquid crystal display I1 and a flyback type electrical conversion device 100 having a synchronous rectification function and capable of operating in continuous and discontinuous current modes. 9 M441132 This LCD screen 1 is used to display the picture and receive a DC output voltage as a source of power. The flyback power conversion device 100 includes a rectification filter module 3, a transformer 4, a primary side switch circuit 5, a first output filter circuit 6, a secondary side switch circuit 7, and a potential polarity detection circuit 8 Stage side current detecting circuit 9. The rectifying and filtering module 3 is configured to receive an AC voltage and rectify the AC voltage to obtain a DC chopping voltage. In more detail, the rectification filter module 3 has an EMI filter circuit 31 and a bridge type rectification and power frequency filter circuit 32. The EMI filter circuit 31 is configured to receive an AC from an external network (not shown). Voltage, and filtering the alternating voltage to generate an output' and the flyback power conversion device 1 uses its own EMI filter circuit 31 to avoid interfering with a high frequency noise generated by itself, and also avoiding Interfered with a high frequency noise from the grid. The bridge rectification and power frequency filter circuit 32 is electrically connected to the EMI filter circuit 31 to receive the output, and the received output is subjected to full-wave rectification and capacitance filtering to generate the filter voltage having a certain voltage ripple. The transformer 4 has a primary side winding Np, a first secondary side winding Ns, and a primary side detecting winding Ndet. Each of the windings Np, Ns has a striking end and a non-tapping end, and the striking end of the primary side winding Np, the striking end of the first secondary side winding Ns, and the striking end of the secondary side detecting winding Ndet Having the same potential polarity, the non-tapping ends of the windings Np, Ns, Ndet also have the same potential polarity and are opposite in polarity to the potentials of the terminals. The non-tapped end of the primary side winding Np is electrically connected to the bridge rectification 10 M441132 and the power frequency filter circuit 32 to receive the filtered voltage. The primary side switch circuit 5 is electrically connected between a primary side ground GND1 and a dot end of the primary side winding Np, and is controlled according to a pulse signal to switch between conduction and non-conduction to correspondingly change the primary side winding. The potential polarity of the two ends of the NP changes the polarity of the potential of the two ends of the first secondary winding Ns and the secondary detection winding Ndet, and generates an alternating current induction in the first secondary winding Ns. Voltage. The primary side switching circuit 5 has a primary side switch 51 and a resistor 52. The primary side switch 51 has a first end electrically connected to the dot end of the primary side winding Np, a second end, and a control terminal for receiving the pulse wave signal. The resistor 52 has a first end electrically connected to the second end of the primary side switch η and a second end electrically connected to the primary side ground GND1. The main function of the resistor 52 is to sample a switching current flowing through the second end of the primary side switch 51, and use the switching current to generate a primary feedback fed back to a modulation control chip (not shown) at its first end. The modulation control chip also samples the secondary side output voltage of the first secondary side winding Ns of the transformer 4 and the non-input end of the transformer 4, and is sampled and fed back to the modulation control chip according to the secondary side output voltage. The result of comparing the secondary feedback voltage with the primary feedback voltage adjusts a duty conduction ratio of the pulse wave k outputted by the modulation control chip to stabilize the output of the corresponding flyback power conversion device 100 The first output voltage of the DC. In the first preferred embodiment, the primary side switch 51 is an N-type metal oxide half field effect transistor (MOSFET), and the first end is a drain and the second end is a source. The end is the gate. 11 The first-output wave circuit 6 is electrically connected to the first to receive the money voltage, and is subjected to a DC (four) voltage. The first output filter circuit 6 has a -first inductance 61, an = output capacitor 62 and a second capacitor 63. , „ ^ a first—the first inductor 61 has a first end of a striking end of an electric remote side winding Ns, and the connecting person 62 has an electrical connection with the first electric one. The first end of the first end, and the second u capacitor 63 connected to the secondary side ground GND2 are electrically connected to the first end of the second end of the first inductor 61, and the second side of the electrical connection stage side is grounded G dirty The second end, and the first end of the second capacitor 63: the first output voltage. The secondary side switching circuit 7 is electrically connected between the first output filter circuit 6 and the first-second side winding Ns. And controlled to switch between conduction and non-conduction to provide or interrupt a current transmission path between the first output filter circuit 6 and the first secondary side winding Ns. The secondary side switch circuit 7 has a first The rectifying transistor 71 has a first end electrically connected to the non-tapping end of the first secondary side winding Ns, and a second % ' and a control end electrically connected to the secondary side ground GND2 In the first preferred embodiment, the first rectifying transistor 71 is an N-type MOS field-effect transistor, and One end is a drain, the second end is a source, and the control end is a gate. The potential polarity detecting circuit 8 is electrically connected between the secondary side detecting winding Ndet and the secondary side switching circuit 7, and according to the The polarity of the potential of the two ends of the secondary side detecting winding Ndet is used to detect whether the primary side switching circuit (5) is turned on to determine whether the secondary side switching circuit 7 is set to be non-conducting. 12 M441132 When the switching circuit (5) is turned on, the 兮4 level two*" 〇疋 primary 将. The hai-human-level side switching circuit 7 is set to be non-conducting. The potential polarity detecting circuit 8 has a __ transistor Η, a resistor 82 and a Zener diode 83. The 4-electrode 81 has a first end connected to the control end of the first rectifying transistor 71 from the Doosan, and electrically connected to the secondary Side ground GND2 second
端，及-控制端。在該第一較佳實施例中，該價測電晶體 8】是層雙載子接面電晶體，且第—端是射極（_㈣，End, and - control end. In the first preferred embodiment, the price measuring transistor 8] is a layer double-carrier junction transistor, and the first end is an emitter (_(four),
孩電位極性偵測電路 第二端是集極（collector) ’控制端是基極（base)<>並且為 了便於示圖，該領測電晶體81的第一端與該第一整流電晶 體71的控制端都各標示一個符號G，用以表示標有相同符 號G的該等端點是電連接在―起。 該電阻82具有一電連接該次級側偵測繞組Ndet的打點 端的第一端，及一電連接該偵測電晶體81的控制端的第二 端。該齊納一極體8 3具有一電連接該次級侧接地GND2的 陽極’及一電連接該電阻82的第二端的陰極。 該次級侧電流债測電路9電連接於該第一次級側繞組 Ns與該次級側開關電路7之間，並偵測流經該第一次級側 繞組Ns的一個次級側電流的大小，以決定將該次級側開關 電路7設定成導通或不導通。該次級側電流由該次級側地 GND2依序流經該第一整流電晶體71的第二端到第一端、 該第一次級侧繞組Ns的非打點端到打點端，最後流至該第 一電容62的第一端。 該次級侧電流偵測電路9具有一電流偵測互感器91、 13 M441132 一電容92、一第一電阻93' —齊納二極體94、一第二電阻 95、一第一開關96、一第三電阻97、一第二開關98及一 第三開關99。 該電流偵測互感器91具有一第一繞組N1及一第二繞 組N2。該第一繞組N1及第二繞組N2分別具有一打點端及 一非打點端，該第一繞組N1的打點端電連接該第一整流電 晶體71的第一端，該第一繞組N1的非打點端電連接該第 一次級侧繞組Ns的非打點端，且該第一繞組N1的打點端 與該第二繞組N2的打點端極性相同，該第一繞組m的非 打點端與該第二繞組N2的非打點端極性也相同，當有變化 的電流流過該第一繞組N1時，該第一及第二繞組则、N2 的該等打點端與該等非打點端的電位極性相反。 s電谷92八有電連接該第二繞組N2的打點端的第 端及電連接該第二繞組N2的非打點端的第二端。該 =電阻93具有-電連接該第二繞組N2的打點端的第— 端及-電連接該第二繞組N2的非打點端的第二端。兮齊 ，二極體94具有一電連接該第二繞组N2的打點端的陽 5及電連接該第二繞組N2的非打點端的陰極。 該第二電阻95具有一電連接該第二繞組 端的第-端，及-第二端。該第一開關96具有一電= ^ ^出遽波電路6的第—電感61的第二端的第—端、— 電：接該齊納二極體94的陽極的第二端， 二電阻95的坌山认仏*, 疋按及第 接第-門關j 該第三電阻97具有-電連 接第開關％的第二端的第-端’及一電連接該次級側接 14 M441132 地GND2的第二端。該第二開關 具有—電連接該第一輸 出山濾波料6的第一電感61的第二端的第一端一第二 端，及-電連接該齊納二極體94的陽極的控制端。該第三 開關"具有一電連接該次級侧接地GND2的第一端、一電 連接該第二開關98的第二端的第二端，及一電連接該第二 開關98的控制端的控制端。 在該第-較佳實施例中，該第__ 96及該第二開關The second end of the potential detecting circuit of the child potential is a collector's control terminal is a base <> and for convenience of illustration, the first end of the pilot transistor 81 and the first rectifying current The control terminals of the crystal 71 are each marked with a symbol G to indicate that the terminals marked with the same symbol G are electrically connected. The resistor 82 has a first end electrically connected to the striking end of the secondary side detecting winding Ndet, and a second end electrically connected to the control end of the detecting transistor 81. The Zener diode 8 3 has an anode electrically connected to the secondary side ground GND2 and a cathode electrically connected to the second end of the resistor 82. The secondary side current debt measuring circuit 9 is electrically connected between the first secondary side winding Ns and the secondary side switching circuit 7, and detects a secondary side current flowing through the first secondary side winding Ns The size is determined to set the secondary side switching circuit 7 to be either conductive or non-conductive. The secondary side current flows from the second side of the first rectifying transistor 71 to the first end, the non-tapping end of the first secondary side winding Ns to the striking end, and finally flows from the secondary side ground GND2. To the first end of the first capacitor 62. The secondary side current detecting circuit 9 has a current detecting transformer 91, 13 M441132, a capacitor 92, a first resistor 93' - a Zener diode 94, a second resistor 95, a first switch 96, A third resistor 97, a second switch 98 and a third switch 99. The current detecting transformer 91 has a first winding N1 and a second winding N2. The first winding N1 and the second winding N2 respectively have a dot end and a non-dip end. The dot end of the first winding N1 is electrically connected to the first end of the first rectifying transistor 71, and the first winding N1 is non- The dot end is electrically connected to the non-tapping end of the first secondary side winding Ns, and the dot end of the first winding N1 and the dot end of the second winding N2 have the same polarity, and the non-tapping end of the first winding m and the first The polarity of the non-tapping end of the two windings N2 is also the same. When a varying current flows through the first winding N1, the potentials of the first and second windings, N2, and the non-injecting ends are opposite in polarity. The electric valley 92 has a first end electrically connected to the striking end of the second winding N2 and a second end electrically connected to the non-tapping end of the second winding N2. The = resistance 93 has a first end electrically connected to the striking end of the second winding N2 and a second end electrically connected to the non-tapping end of the second winding N2. The diode 94 has a cathode 5 electrically connected to the dot end of the second winding N2 and a cathode electrically connected to the non-doping end of the second winding N2. The second resistor 95 has a first end electrically connected to the second winding end, and a second end. The first switch 96 has a first end of the second end of the first inductor 61 of the chopper circuit 6, and a second end of the anode of the Zener diode 94. The third resistor 97 has a first end that electrically connects the second end of the switch % and an electrical connection that connects the secondary side 14 M441132 to the ground GND2 The second end. The second switch has a first end and a second end electrically connected to the second end of the first inductor 61 of the first output mountain filter 6, and a control terminal electrically connected to the anode of the Zener diode 94. The third switch has a first end electrically connected to the secondary side ground GND2, a second end electrically connected to the second end of the second switch 98, and a control terminal electrically connected to the second switch 98. end. In the first preferred embodiment, the __96 and the second switch
98疋NPN雙裁子接面電晶體，且各自的第一端是集極，第 二端是射極，控制端是基極；該第三開關99是PNP雙載子 接面電晶體，且第一端是集極，第二端是射極，控制端是 基極。 、，閱® 1及gj 2，該第-較佳實施例操作於連續電流模 式（CCM)時的動作原理詳述如下。 (1)田該脈波彳s號為從高準位切換到低準位時：98疋NPN double-cut junction transistor, and each of the first ends is a collector, the second end is an emitter, and the control end is a base; the third switch 99 is a PNP bipolar junction transistor, and The first end is the collector, the second end is the emitter, and the control end is the base. The operation principle of the first preferred embodiment operating in continuous current mode (CCM) is detailed below. (1) When the pulse 彳s number is switched from the high level to the low level:
/初級側開關51由導通士刀換成不導通，該初級側繞組 Np的非打點端的電極性由正變負，該打點端的電位極性由 負殳正。由於該第一次級側繞組Ns的打點端、該次級侧偵 XJ、’堯、’且Ndet的打點端與該初級侧繞組Np的打點端的電位 極性均相肖’所以該第一次級側繞组Ns及該次級側傾測繞 組Ndet的打點端的電位極性追隨該初級側繞組Np的打點 端的電位極性而由負變正，該第一次級側繞組Ns及該次級 側偵測繞組Ndet的非打點端的電位極性均由正變負，且該 第一次級侧繞組Ns的打點端的該感應電壓的大小實質地為 該第一輸出濾波電路6輸出的該第一輸出電壓的大小。 15 M441132 同時，該第一整流電晶體71的第一端接收到該苐一次 級側繞組Ns的非打點端的負電位，該第一整流電晶體71 的第二端的電位是該次級側地GND2的0V電位，使得該第 一整流電晶體71的一寄生二極體711的陽極的電位高於陰 極的電位而先導通。 接著’該寄生二極體711導通後的該次級側電流經過該 偵測電流的互感器91的第一繞組N1而使該第二繞組N2產 生一感應電流通過該第一電阻93轉變成一控制電壓，當該 控制電壓達到並超過該第一開關96的一導通電壓時，該第 一開關96導通，從而使該第二開關98導通且該第三開關 99不導通，使得該第一輸出濾波電路6輸出的該第一直流 輸出電壓通過該第二開關98的第一及第二端快速地輸出到 5亥第一整流電晶體71的控制端，也就是Vgs(7 一The primary side switch 51 is replaced by a conduction knife which is non-conducting, and the polarity of the non-tapping end of the primary side winding Np is positively negative, and the polarity of the potential of the switching end is negatively positive. Since the striking end of the first secondary side winding Ns, the secondary side detecting XJ, '尧, ' and the dot end of the Ndet and the tapping end of the primary side winding Np are in the same polarity, the first secondary The potential polarity of the side winding Ns and the striking end of the secondary side detecting winding Ndet changes from negative to positive with the polarity of the potential of the striking end of the primary side winding Np, and the first secondary side winding Ns and the secondary side detection The potential polarity of the non-tapping end of the winding Ndet is positively negative, and the magnitude of the induced voltage of the striking end of the first secondary side winding Ns is substantially the magnitude of the first output voltage output by the first output filter circuit 6. . 15 M441132 At the same time, the first end of the first rectifying transistor 71 receives the negative potential of the non-injecting end of the first-stage winding Ns, and the potential of the second end of the first rectifying transistor 71 is the secondary side GND2 The potential of 0 V is such that the potential of the anode of a parasitic diode 711 of the first rectifying transistor 71 is higher than the potential of the cathode. Then, the secondary side current after the parasitic diode 711 is turned on passes through the first winding N1 of the current detecting current transformer 91, so that the second winding N2 generates an induced current through the first resistor 93 to be converted into a control. a voltage, when the control voltage reaches and exceeds a turn-on voltage of the first switch 96, the first switch 96 is turned on, so that the second switch 98 is turned on and the third switch 99 is not turned on, so that the first output is filtered. The first DC output voltage outputted by the circuit 6 is quickly outputted through the first and second ends of the second switch 98 to the control end of the 5th first rectifying transistor 71, that is, Vgs (7
VcepspVgWh)，參數Vgs(71)為該第一整流電晶體71的 拇極與源極之間的電壓、Vout為該第一輸出濾波電路6輪 出的該第一輸出電壓、Vce(98)為該第二開關98的集極與射 極間的飽合導通電壓、Vgs⑽為該第一整流電晶體71的柵 極與源極之間的開啟電壓，進而驅動該第一整流電晶體71 導通’並且該第-整流電晶體71導通後的一次級側電流傳 輸路徑依序經由該次極侧地GND2 &、該第一整流電晶體 的源極収極、該變壓器4的第—次級側繞組Ns的非打 點端到打點端’最後到達該第一輸出濾波電路6的第一及 第二電容62、63的第一端及該電感61進行儲能。 當該第一整流電晶體71導通時，該變壓器4的氣隙 16 M441132 (gap)中在初級側開關51導通期間所儲存的能量依序透過 該第一次級側繞組Ns及該第一整流電晶體71釋放給該第 一輸出濾波電路6，以提供給該液晶螢幕1。 由於該第一整流電晶體71的源極與沒極之間的阻抗很 小，故當電流流過該第一整流電晶體71的源極與汲極時， 所產生的功耗也很小，達到利用該第一整流電晶體71作同 步整流以提升電源轉換效率，而避免現有液晶顯示器產品 的反激式開關電源因採用肖特基二極體做整流而使電源轉 換效率低的缺點。 (2)當該脈波信號從低準位切換到高準位時： 該初級側開關51由不導通切換成導通，該初級側繞組VcepspVgWh), the parameter Vgs(71) is the voltage between the thumb and the source of the first rectifying transistor 71, and Vout is the first output voltage of the first output filter circuit 6, and Vce(98) is The saturation conduction voltage between the collector and the emitter of the second switch 98, Vgs (10) is the turn-on voltage between the gate and the source of the first rectifying transistor 71, thereby driving the first rectifying transistor 71 to conduct ' And the primary-stage current transmission path after the first rectifying transistor 71 is turned on sequentially passes through the sub-pole side ground GND2 &, the source of the first rectifying transistor, and the first-second side of the transformer 4 The non-tapping end of the winding Ns to the striking end 'finally reaches the first end of the first and second capacitors 62, 63 of the first output filter circuit 6 and the inductor 61 for energy storage. When the first rectifying transistor 71 is turned on, the energy stored in the air gap 16 M441132 (gap) of the transformer 4 during the conduction of the primary side switch 51 sequentially passes through the first secondary side winding Ns and the first rectification. The transistor 71 is discharged to the first output filter circuit 6 to be supplied to the liquid crystal screen 1. Since the impedance between the source and the gate of the first rectifying transistor 71 is small, when the current flows through the source and the drain of the first rectifying transistor 71, the power consumption is small. The use of the first rectifying transistor 71 for synchronous rectification to improve the power conversion efficiency, and avoiding the disadvantage of the power conversion efficiency of the flyback switching power supply of the existing liquid crystal display product by using the Schottky diode for rectification. (2) When the pulse wave signal is switched from the low level to the high level: the primary side switch 51 is switched from non-conducting to conducting, the primary side winding
Np的非打點端的電位極性由負變正，打點端的電位極性由 正變負。由於該第一次級側繞組Ns的打點端、該次級側偵 ’貝J ’、堯組Ndet的打點端與該初級側繞組Np的打點端極性均 相同，所以該第一次級侧繞組Ns及該次級側偵測繞組Ndet 的打點端的電位極性均追隨該初級側繞組Np的打點端的電 極!生由正變負，該第一次級侧繞组Ns丨該次級侧伯測繞組The polarity of the potential of the non-tap end of Np is changed from negative to positive, and the polarity of the potential at the end of the tap is positively negative. Since the striking end of the first secondary side winding Ns, the secondary side detecting end, and the striking end of the first side winding Np are the same polarity, the first secondary side winding The polarity of the potential of the Ns and the secondary side detecting winding Ndet follow the electrode of the striking end of the primary side winding Np! The positive secondary negative winding Ns 丨 the secondary side secondary winding
Ndet的非打點端的電極性均由負變正，且該次級側偵測繞 汲Ndet的非打點端的電位是該次級側地的電 位0 由於該齊納二極體83的陽極電連接〇v電位的該次級 ’i接地GND2，陰極經由該電阻82電連接到該次級侧谓測 、堯組Ndet的打點端（負電位），所以此時該齊納二極體83 正向導通’在該齊納二極體83的陰極產生_Q 7v的電塵， 17 M441132 並施加於PNP的該偵測電晶體81的控制端，該偵測電晶體 81迅速導通’該第一整流電晶體71的該控制端的電荷經由 該偵測電晶體81的第一端、第二端導至該次級側接地 GND2被迅速地泄放掉，該第一整流電晶體71迅速地由導 通切換成不導通狀態，從而避免在該初級側開關51由不導 通切換為導通時’該第一整流電晶體71未即時被切換成不 導通而造成該第一輸出濾波電路6的電能被倒灌回該變壓 器4中，因此產生一逆向電流由該第一整流電晶體71的汲 極流向源極最後到達該次級側地GND2，使得該第一整流電 晶體71在做關斷時在自身的汲極與源極間產生該較高的尖 峰電壓，且該尖峰電壓最終.可能導到先前技術中所述的該 同步整流金氧半％效電晶體的沒極與源極之間，而導致該 同步整流金氧半場效電晶體因耐壓不足而被擊穿的問題。 該第一較佳實施例操作於不連續電流模式（DCM ) 時，其動作模式與工作在連續電流模式的差異在於：該初 級側開關51不導通期間Toff，該變壓器4在該初級側開關 51導通時所儲存在該變壓器4的氣隙中的能量從該第一次 級側繞組Ns釋放給該第一輸出濾波電路6，該變壓器4氣 隙中的能量於一釋能期間toff<T〇ff全部釋放完畢，此時該 電流偵測互感器91的該第一繞組N1因沒有電流流過使 得該第二繞阻N2的打點端與非打點端之間無感應電壓，該 NPN的第一開關96由導通切換為不導通狀態，該pNp的第 三開關99由不導通變為導通狀態，該第一整流電晶體η 的控制端（栅極）的電荷被快速泄放掉，:當該初級側 18 M441132 開關51由導通變為不導通時，經過該釋能期間耐後，該 第正流電體71就會被該次級側電流侦測電路9關斷， 以防止該初級側開關51不導通期間醫的剩餘時間 (△ toff Toff toff)出現該第—輪出滤波電路6中的電能 倒灌到該變Μ器4中引起該第—整流電晶體71的汲極與源 極因耐壓不足而被該尖峰電壓鑿穿的問題。The polarity of the non-doped end of the Ndet is positively changed from negative, and the potential of the secondary side detecting the non-doped end of the Ndet is the potential of the secondary side. 0. The anode electrical connection of the Zener diode 83. The secondary potential of the v potential is grounded to the ground GND2, and the cathode is electrically connected to the secondary side of the secondary side, the n-point of the Ndet (negative potential), so that the Zener diode 83 is forwarded. 'The electric dust of _Q 7v is generated at the cathode of the Zener diode 83, and 17 M441132 is applied to the control end of the detecting transistor 81 of the PNP, and the detecting transistor 81 is quickly turned on 'the first rectifying electric current The charge of the control terminal of the crystal 71 is rapidly discharged through the first end and the second end of the detecting transistor 81 to the secondary side ground GND2, and the first rectifying transistor 71 is rapidly switched from conduction to a non-conducting state, thereby preventing the first rectifying transistor 71 from being switched to non-conducting when the primary side switch 51 is switched from non-conducting to conducting, causing the electric energy of the first output filter circuit 6 to be poured back to the transformer. 4, thus generating a reverse current from the first rectified current The drain of the body 71 flows to the source and finally reaches the secondary side ground GND2, so that the first rectifying transistor 71 generates the higher peak voltage between its own drain and source when it is turned off, and the peak The voltage may eventually lead to the between the non-polar and the source of the synchronous rectification MOS half-effect transistor described in the prior art, causing the synchronous rectification MOS field-effect transistor to be broken down due to insufficient withstand voltage. The problem. When the first preferred embodiment operates in the discontinuous current mode (DCM), the difference between the operation mode and the operation in the continuous current mode is that the primary side switch 51 is not conducting the period Toff, and the transformer 4 is at the primary side switch 51. The energy stored in the air gap of the transformer 4 during the conduction is released from the first secondary side winding Ns to the first output filter circuit 6, and the energy in the air gap of the transformer 4 is during a release period toff<T〇 The ff is completely released. At this time, the first winding N1 of the current detecting transformer 91 has no current flowing, so that there is no induced voltage between the striking end and the non-tapping end of the second winding N2, and the first of the NPN is The switch 96 is switched from the conduction state to the non-conduction state, the third switch 99 of the pNp is changed from the non-conduction state to the conduction state, and the charge of the control terminal (gate) of the first rectifying transistor η is quickly discharged. When the primary side 18 M441132 switch 51 is turned off from conduction, after the release period, the first positive current body 71 is turned off by the secondary side current detecting circuit 9 to prevent the primary side switch 51 time remaining during the period of non-conduction ( △ toff Toff to ff) the electric energy in the first-out filter circuit 6 is poured into the damper 4, causing the drain and the source of the first rectifying transistor 71 to be punctured by the peak voltage due to insufficient withstand voltage. The problem.
參閱圖3’是本新型液晶顯示產品之第二較佳實施例， 其與該第-較佳實施例類似，差異在於：該第二較佳實施 例的該變1器4相較於該第—較佳實施例（見圖υ還具有 第一次級侧繞組Ns2,且該第二較佳實施例還包含一提供 -直流的第二輸出電壓的輸出模组1〇，及一主基板電路 2〇,且該第-及第二開關96、98的第—端是電連接該輸出 模、’且10輸出該第一輸出電壓的一輸出端 該主基板電路20主要功能為圖像處理，並電連接該第3 is a second preferred embodiment of the liquid crystal display product of the present invention, which is similar to the first preferred embodiment. The difference is that the variable device 4 of the second preferred embodiment is compared to the first a preferred embodiment (see also a first secondary side winding Ns2, and the second preferred embodiment further comprises an output module 1A for providing a second output voltage of -DC, and a main substrate circuit 2〇, and the first end of the first and second switches 96, 98 is electrically connected to the output mode, and 10 outputs an output end of the first output voltage. The main substrate circuit 20 is mainly used for image processing. And electrically connected to the first
一輸出遽波電路6以接收該第— 晶螢幕1是電連接該輸出模組1〇 如：16V 〇 輸出電壓，如：5V。該液 以接收該第二輸出電壓， 該第二次級側繞組Ns2具有一打點端及一非打點端， 且該第一次級側繞组Ns2的兩端的電位極性對應該初級側 繞組Np的兩端的電位極性作改變，並於該第二次級側繞組 Ns2產生-呈交流的第二感應電壓。在該第二較佳實施例， 該初級側繞組Np的打點端與該第二次級侧繞組脱的打點 端具有相同的電位純，該初級側繞組Np的非打點端與該 第二次級侧繞組Ns2的非打點端也具有相㈣電位極性。 19 M441132 該輸出模組ίο包括一第二輸出渡波電路13、—第二次 級側開關電路14及一準位移位（level-shift)電路15。 該第二輸出濾波電路13電連接於該第二次級側繞組 Ns2以接收該第—感應電壓，並進行遽波以得到從該輸出端 101輸出的該第二輸出電壓。在該第二較佳實施例中，該第 一輸出濾波電路13與該第一輪出濾波電路6的設計方式相 同，所以相關實施方式可以參閱圖丨的說明而不再贅述。 該第二次級侧開關電路14電連接於該第一次級側繞組 Ns與該第二次級側繞組Ns2之間，且受控制切換於導通與 不導通之間，以提供或中斷該第二輸出濾波電路13與該第 一次級側繞組Ns之間的電流傳遞路徑。 該第二次級側開關電路丨4具有一第二整流電晶體 141 ’且該第二整流電晶體ι41具有一寄生二極體1411。該 第二整流電晶體141具有一電連接該第二次級侧繞組ns2 的非打點端的第一端、一電連接該第一次級側繞組Ns的打 點端的第二端’及一控制端。在該第二較佳實施例中，該 第二整流電晶體141是N型金氧半場效電晶體，且第一端 是汲極’第二端是源極，控制端是閘極。 該準位移位電路15電連接於該電位極性偵測電路8與 該第二次級側開關電珞14之間，並根據該電位極性偵測電 路8偵測該初級側開關電路5是否導通，以決定是否將該 第二次級側開關電路14設定成不導通。該電位極性偵測電 路8是在偵測到該初級侧開關電路5導通時，將該第二次 級側開關電路14的第二整流電晶體141設定成不導通。 20 M441132 —該準位移位電路15具有一電阻151、一電容⑸及一 體153。β亥電阻151具有一電連接該價測電晶體^的 端的第一端，及一電連接該第二整流電晶體141的控 制端的第—端。該電容152的兩端分別電連接於該電阻⑸ 、第端及第一端。該二極體153具有一電連接該第二整 =電阳體141 #第二端的陽極’及—電連接該第二整流電 晶體141的控制端的陰極。 該第二較佳實施例提供該第一輸出電麼的方式相同於 該第7較佳實施例’故可參考上述該第一較佳實施例的說 明’以下僅就該第二較佳實施例提供該第二輸出電壓的動 作原理作說明。 ⑴當該反激式電源轉換裝置100工作在連續或不連續 電流模式且該脈波信號為從高準位切換到低準位時： 該變！器4開始釋放能量且該第—次極側繞組吣、該 第二次極侧繞組Ns2、該次極㈣測繞组_的電位極性 均反轉，該等繞組Ns、Ns2、Ndet的非打點端的電位極性 由正變為負，該等繞組Ns、Ns2、Ndet的打點端的電位極 性由負變為正，此時該第一整流電晶體71的寄生二極體 711、該第二整流電晶！| 141的寄生二極體ΐ4ιι正向導通， 同時該電流偵測互感_ 91 #該第一繞組N1得到一實質呈 線性下降的電流，使得該電流_互感器91的第二繞植N2 的非打點端相對打點端感應-正電壓，進而使得該第一開 關96導通’該第二開關98導通，該第—整流電晶體乃的 控制端所接收到的一電壓由低電位VL變為高電位VH,而 21 M441132 使該第一整流電晶體71切換成導通。 舉例說明，該低電位νΐ^=να81=νπ99=0·2ν，參數 Vec81為該偵測電晶體81的射極與集極之間的飽合導通壓 降（如：0.2V)，參數Vec99為第三開關99的射極與集極之 間的飽合導通壓降（如：0.2V );該高電位vH=Vout2 —An output chopper circuit 6 for receiving the first crystal screen 1 is electrically connected to the output module 1 such as: 16V 〇 output voltage, such as: 5V. The liquid receives the second output voltage, the second secondary side winding Ns2 has a punctual end and a non-tapping end, and the potential polarity of the two ends of the first secondary side winding Ns2 corresponds to the primary side winding Np The polarity of the potential at both ends is changed, and a second induced voltage of alternating current is generated in the second secondary side winding Ns2. In the second preferred embodiment, the striking end of the primary side winding Np and the striking end of the second secondary side winding have the same potential purity, and the non-tapping end of the primary side winding Np and the second sub The non-tapped end of the side winding Ns2 also has a phase (four) potential polarity. 19 M441132 The output module ίο includes a second output wave circuit 13, a second stage side switch circuit 14, and a level-shift circuit 15. The second output filter circuit 13 is electrically connected to the second secondary side winding Ns2 to receive the first induced voltage, and is chopped to obtain the second output voltage outputted from the output terminal 101. In the second preferred embodiment, the first output filter circuit 13 is designed in the same manner as the first output filter circuit 6. Therefore, the related embodiments may be referred to the description of the drawings and will not be described again. The second secondary side switch circuit 14 is electrically connected between the first secondary side winding Ns and the second secondary side winding Ns2, and is controlled to be switched between conducting and non-conducting to provide or interrupt the first A current transfer path between the second output filter circuit 13 and the first secondary side winding Ns. The second secondary side switching circuit 丨4 has a second rectifying transistor 141' and the second rectifying transistor ι41 has a parasitic diode 1411. The second rectifying transistor 141 has a first end electrically connected to the non-tapping end of the second secondary side winding ns2, a second end electrically connected to the striking end of the first secondary side winding Ns, and a control end. In the second preferred embodiment, the second rectifying transistor 141 is an N-type MOS field effect transistor, and the first end is a drain. The second end is a source and the control end is a gate. The quasi-displacement circuit 15 is electrically connected between the potential polarity detecting circuit 8 and the second secondary side switch unit 14 , and detects whether the primary side switching circuit 5 is turned on according to the potential polarity detecting circuit 8 . To determine whether to set the second secondary side switching circuit 14 to be non-conductive. The potential polarity detecting circuit 8 sets the second rectifying transistor 141 of the second-stage side switching circuit 14 to be non-conductive when detecting that the primary side switching circuit 5 is turned on. 20 M441132 - The quasi-displacement circuit 15 has a resistor 151, a capacitor (5) and a body 153. The ?-resistance resistor 151 has a first end electrically connected to the end of the price measuring transistor, and a first end electrically connected to the control end of the second rectifying transistor 141. The two ends of the capacitor 152 are electrically connected to the resistor (5), the first end and the first end, respectively. The diode 153 has an anode electrically connected to the second end of the second positive electrode 141 # and a cathode electrically connected to the control end of the second rectifying transistor 141. The second preferred embodiment provides the first output power in the same manner as the seventh preferred embodiment. Therefore, reference may be made to the description of the first preferred embodiment. The following is only the second preferred embodiment. The principle of operation of providing the second output voltage is explained. (1) When the flyback power conversion device 100 operates in a continuous or discontinuous current mode and the pulse signal is switched from a high level to a low level: the change! The device 4 starts to release energy and the polarity of the potential of the first-stage side winding 吣, the second-stage side winding Ns2, and the second-pole (four) measuring winding _ are reversed, and the non-dots of the windings Ns, Ns2, and Ndet are reversed. The potential polarity of the terminal changes from positive to negative, and the polarity of the potential of the winding ends of the windings Ns, Ns2, and Ndet changes from negative to positive. At this time, the parasitic diode 711 of the first rectifying transistor 71, the second rectifying electric crystal ! The parasitic diode 141 of the 141 is forwarded, and the current detecting mutual inductance _ 91 # the first winding N1 obtains a substantially linearly decreasing current, so that the second current of the current _ transformer 91 is non-N2 The striking end senses a positive voltage with respect to the striking end, thereby causing the first switch 96 to be turned on. The second switch 98 is turned on, and a voltage received by the control terminal of the first rectifying transistor is changed from a low potential VL to a high potential. VH, and 21 M441132 switches the first rectifying transistor 71 to be turned on. For example, the low potential νΐ^=να81=νπ99=0·2ν, the parameter Vec81 is the saturation conduction voltage drop between the emitter and the collector of the detecting transistor 81 (for example, 0.2V), and the parameter Vec99 is a saturation conduction voltage drop between the emitter and the collector of the third switch 99 (eg, 0.2V); the high potential vH=Vout2 —
Vce98=16V—0.2V=15.8V，參數v〇ut2為該第二輸出電壓 (如：16V)’參數Vce98為該第二開關98飽合導通時集極 與射極間的壓降（如：〇·2ν);該第一整流電晶體71的基極 與射極間的壓差為該低電位VL=0.2V時不導通，且該第一 整流電晶體71的基極與射極間的壓差為該高電位 VH=15.8V時為導通。 同時根據電容兩端電壓不能突變的原理，該第二整流 電晶體141的控制端被施加的一電壓vg141 = (V61-Vfl53 + VH— VL)> Vgs(th)，故此時該第二整流電晶體141也開 始導通。參數V61為該第一電感61的第一端的電壓，參數 Vfl53為該二極體153的正向導通電壓，參數vgs(th)為該 第二整流電晶體141的柵極與源極之間的開啟電壓。 舉例說明 ’ V61 = 15.8V、Vfl53 = 0.7V、VH = 15.8、 VL = 0.2V、Vgs(th) = 3 5V，則施加於該第二整流電晶體 141的柵極與源極之間的電壓¥85141 = ¥8141 — 乂61 = ¥11 — VL-Vfl53= 15.8V —0.2V—〇.7V= 14.9V> Vgs(th)，該第二 整流電晶體141導通》 該第—整流電晶體71及該第二整流電晶體141均導 通’該變遷器4的氣隙中的能量除了透過該第一次級側繞 22 M441132 組Ns釋放給該第一輪出濾波電路6，還透過該第一次級側 繞組Ns及該第二次級側繞組Ns2釋放給該第二輪出濾波電 路13。 (2)當該反激式電源轉換裝置1〇〇工作在連續或不連續 電流模式且該脈波信號為從低準位切換到高準位時： 該變1器4開始儲能且該等繞組NS、Ns2、Ndet的電 位極性反轉，該等繞組Ns、Ns2、Ndet的非打點端的電位 極性由負變正’該等繞組Ns、Ns2、Ndet的打點端的電位 極性由正變負，該變壓器4的該次級側偵測繞組Ndet的非 打點端電連接該次級側地GND2，故此時該齊納二極體Μ 正向導通並於陰極產生一約為—〇7v的電壓使該偵測電晶 體81導通，該第一整流電晶體71的控制端由高電位變 為低電位VL=Vec81=0.2V，參數Vec81為PNp的該偵測電 晶體81飽合導通時射極與集極之間的壓降（例如〇2)，該 第一整流電晶體71切換為不導通，同時根據電容兩端電壓 不能突變的原S，該第二整流電晶體⑷&控制端與源極 端產生一電壓 Vgsl41，，= Vgsl41 — (VH — VL)= vh — VL — Vfl53 — (VH - VL) = 一 Vfl53 二—〇 7V < Vgs(th)，參數 Vgs(th)為該第二整流電晶體141的栅極與源極之間的開啟 電壓（例如3.5V)，故此時該第二整流電晶體141也開始停 止導通。 (3)田忒反激式電源轉換裝置1〇〇工作在不連續電流 模式且該變屡器4全部的能量都釋放給該第一輸出遽波電 路6與該第二輸出遽波電路13日夺，該電流伯測互感器w 23 M441132 的第-繞阻N丨因沒有電流流過而最終使得該第三開關99 導通，該第-整流電晶體71的控制端由高電位VH變為低 電位VL=Vec99 = 0.2V，參數Vec99為該第三開關％飽合 導通時射極與集極之間的壓降，例如〇2v，該第一整流電 拍體71停止通導，同時根據電容兩端電壓不能突變的原 理’該第二整流電晶體141的控制端與源極端產生一電壓 Vgsl41» = Vgsl41 - (VH - VL) = VH^ VL - Vfl53 - (VH -VL)=-Vfl53=-〇.7V<Vgs(th)’ 參數 Vgs⑽為該第二整 流電晶體141的柵極與源極之間的開啟電壓，例如3 5v， 故此時該第二整流電晶體141也開始停止導通。 而該電阻151作用是當該反激式電源轉換裝置1〇〇輸 入的交流電壓被移除時，用來泄放該第二整流電晶體141 控制端殘餘的電荷，以便能讓下一次該反激式電源轉換裝 置100輸入交流電壓（即為市電）時，該第二整流電晶體 141能按正常的時序動作。 综上所述’上述實施例具有以下優點： 1.能操作於連續電流模式，上述的較佳實施例採用該電 位極性偵測電路8偵測該次級侧偵測繞組Ndet 的兩端的電 位極性以判斷該初級側開關電路（5)是否導通，並於該初級 側開關電路（5)導通時控制該第一及第二整流電晶體71、141 由導通快速地設定成不導通，故可避免前述該第一及第二 整流電晶體71、141可能因漏極與源極間耐壓不足而被擊 穿的問題，因此不需採用耐高壓規格的電晶體而得以降低 產品成本。 24 M441132 2.能操作在電源轉換效率較高的連續電流模式，故能符 合高負載之大尺寸面板等多功能的液晶顯示產品的應用需 求。 3. 可同時以多個電晶體（例如該第一及第二整流電晶體 71、141 )做同步整流以分別提供多個不同準位的輸出電壓 (例如第一及第二輸出電壓），以分別供應給不同的負載。 4. 該苐一及第二整流電晶體7丨、丨4丨做整流的損失相較Vce98=16V—0.2V=15.8V, the parameter v〇ut2 is the second output voltage (eg: 16V)' The parameter Vce98 is the voltage drop between the collector and the emitter when the second switch 98 is fully turned on (eg: 〇·2ν); the voltage difference between the base and the emitter of the first rectifying transistor 71 is non-conducting when the low potential VL=0.2V, and between the base and the emitter of the first rectifying transistor 71 The voltage difference is turned on when the high potential VH = 15.8V. At the same time, according to the principle that the voltage across the capacitor cannot be abrupt, a voltage vg141 = (V61-Vfl53 + VH - VL) > Vgs(th) is applied to the control terminal of the second rectifying transistor 141, so the second rectification at this time The transistor 141 also begins to conduct. The parameter V61 is the voltage of the first end of the first inductor 61, the parameter Vfl53 is the forward voltage of the diode 153, and the parameter vgs(th) is between the gate and the source of the second rectifying transistor 141. Turn-on voltage. For example, 'V61 = 15.8V, Vfl53 = 0.7V, VH = 15.8, VL = 0.2V, Vgs(th) = 3 5V, the voltage applied between the gate and the source of the second rectifying transistor 141 ¥85141 = ¥8141 — 乂61 = ¥11 — VL-Vfl53= 15.8V —0.2V—〇.7V= 14.9V> Vgs(th), the second rectifying transistor 141 is turned on” The first rectifying transistor 71 And the second rectifying transistor 141 is both turned on. The energy in the air gap of the changer 4 is released to the first output filter circuit 6 through the first secondary side winding 22 M441132 group Ns, and is also transmitted through the first The secondary side winding Ns and the second secondary side winding Ns2 are discharged to the second output filter circuit 13. (2) When the flyback power conversion device 1 〇〇 operates in a continuous or discontinuous current mode and the pulse signal is switched from a low level to a high level: the variable unit 4 starts to store energy and these The potential polarities of the windings NS, Ns2, and Ndet are reversed, and the potential polarities of the non-tapped ends of the windings Ns, Ns2, and Ndet are positively changed from positive to positive, and the polarity of the potential of the winding ends of the windings Ns, Ns2, and Ndet is positively negative. The non-injecting end of the secondary side detecting winding Ndet of the transformer 4 is electrically connected to the secondary side ground GND2, so that the Zener diode is forwardly conducting and generating a voltage of about 〇7v at the cathode. The detecting transistor 81 is turned on, and the control terminal of the first rectifying transistor 71 is changed from a high potential to a low potential VL=Vec81=0.2V, and the detecting transistor 81 whose parameter Vec81 is PNp is fully turned on and the emitter and the set are turned on. The voltage drop between the poles (for example, 〇2), the first rectifying transistor 71 is switched to be non-conducting, and the second rectifying transistor (4) & the control terminal and the source terminal are generated according to the original S whose voltage across the capacitor cannot be abruptly changed. A voltage Vgsl41,, = Vgsl41 — (VH — VL) = vh — VL — Vfl53 — (VH - VL) = Vfl53 〇7V < Vgs(th), the parameter Vgs(th) is the turn-on voltage (for example, 3.5V) between the gate and the source of the second rectifying transistor 141, so the second rectification at this time The transistor 141 also begins to stop conducting. (3) The field flyback power conversion device 1 〇〇 operates in the discontinuous current mode and all the energy of the repeater 4 is released to the first output chopper circuit 6 and the second output chopper circuit 13 The first winding switch N of the current measuring transformer w 23 M441132 finally turns on the third switch 99 because no current flows, and the control terminal of the first rectifying transistor 71 is changed from the high potential VH to the low The potential VL=Vec99=0.2V, the parameter Vec99 is the voltage drop between the emitter and the collector when the third switch is satisfactorily turned on, for example 〇2v, the first rectifying galvanic body 71 stops the conduction, and according to the capacitance The principle that the voltage at both ends cannot be abruptly 'The voltage between the control terminal and the source terminal of the second rectifying transistor 141 generates a voltage Vgsl41» = Vgsl41 - (VH - VL) = VH^ VL - Vfl53 - (VH - VL) = -Vfl53= - 〇.7V < Vgs(th)' The parameter Vgs(10) is the turn-on voltage between the gate and the source of the second rectifying transistor 141, for example, 3 5v, so that the second rectifying transistor 141 also starts to stop conducting at this time. The resistor 151 functions to discharge the residual charge of the control terminal of the second rectifying transistor 141 when the AC voltage input by the flyback power conversion device 1 is removed, so that the next reversal can be made. When the excitation power conversion device 100 inputs an AC voltage (that is, mains), the second rectifying transistor 141 can operate in a normal timing. In summary, the above embodiment has the following advantages: 1. It can operate in a continuous current mode, and the preferred embodiment uses the potential polarity detecting circuit 8 to detect the potential polarity of both ends of the secondary side detecting winding Ndet. To determine whether the primary side switching circuit (5) is turned on, and to control the first and second rectifying transistors 71, 141 to be quickly set to be non-conducting when the primary side switching circuit (5) is turned on, thereby avoiding The first and second rectifying transistors 71 and 141 may be broken due to insufficient withstand voltage between the drain and the source. Therefore, it is not necessary to use a high-voltage-resistant transistor to reduce the product cost. 24 M441132 2. It can operate in the continuous current mode with high power conversion efficiency, so it can meet the application requirements of multi-function liquid crystal display products such as large-size panels with high load. 3. Simultaneous rectification with a plurality of transistors (eg, the first and second rectifying transistors 71, 141) to respectively provide a plurality of output voltages of different levels (eg, first and second output voltages) to Supply to different loads separately. 4. Compared with the loss of rectification of the first and second rectifying transistors 7丨 and 丨4丨
I知以肖特基二極體做整流的功耗損失小得多，因而使上 述較佳實施例的該反激式電源轉換裝置1〇〇具有較高的電 源轉換效率。 綜上所述，上述較佳實施例確實能達成本新型之目 的。 惟以上所述者，僅為本新型之較佳實施例而已，當不 能以此限;t本新㈣施之範圍，即大凡依本新型巾請專利It is known that the power loss of rectification by the Schottky diode is much smaller, so that the flyback power conversion device 1 of the above preferred embodiment has higher power conversion efficiency. In summary, the above preferred embodiment can achieve the object of the present invention. However, the above is only the preferred embodiment of the present invention, and when it is not possible to limit it; t the scope of the new (four) application, that is, the patent of the new type of towel
範圍及新型說明内容所作之簡單的#效變化與修飾皆仍 屬本新型專利涵蓋之範圍内。 【圖式簡單說明】 圖1是本新型液晶顯示產品之第一較佳實施例的一示 圖 圖 意圖。 2是該第一較佳實施例的一 3是本新型液晶顯示產品 時序圖；及 之第二較佳實施例的—示 25 M441132 【主要元件符號說明】 1 .......... 100....... 反激式電源轉換 裝置 101 ....... 輸出端 3 .......... 整流濾波模組 31......... EMI濾波電路 32......... 橋式整流及工頻 濾波電路 4 .......... 變壓器 Np........ 初級側繞組 Ns ........ 第一次級侧繞組 Ns2....... 第二次級側繞組 Ndet…… 次級側偵測繞組 GND1···· 初級側接地 GND2·... 次級側接地 5 .......... 初級側開關電路 51......... 初級側開關 52......... 電阻 6 .......... 第一輸出濾波電 路 61......... 第一電感 62......... 第一電容 63......... 第二電容 7 ..........次級側開關電路 71.........第一整流電晶體 711 .......寄生二極體 8 ..........電位極性偵測電 路 81 .........偵測電晶體 82 .........電阻 83 .........齊納二極體 9 ..........次級側電流偵測 電路 N1 ........第一繞組 N2........第二繞組 91 .........電流偵測互感器 92 .........電容 93 .........第一電阻 94 .........齊納二極體 95 .........第二電阻 96 .........第一開關 97 .........第三電阻 98 .........第二開關 99 .........第三開關 10 .........輸出模組 13.........第二輸出濾波電 26 M441132 路 15…… •…準位移位電路 14…… …第二次極側開關 151… •…電阻 電路 152… •…電容 141 ·.·· …第二整流電晶體 153… •…二極體 1411 .· …寄生二極體 20…… •…主基板電路The simple changes and modifications made by the scope and new descriptions are still covered by this new patent. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a first preferred embodiment of the novel liquid crystal display product. 2 is a timing diagram of the liquid crystal display product of the first preferred embodiment; and 25 M441132 of the second preferred embodiment. [Description of main component symbols] 1 ......... 100....... Flyback power conversion device 101....... Output terminal 3 ..... Rectifier filter module 31... EMI filter circuit 32......... Bridge rectifier and power frequency filter circuit 4 .......... Transformer Np........ Primary side winding Ns .... .... First secondary side winding Ns2....... Second secondary side winding Ndet... Secondary side detection winding GND1···· Primary side ground GND2·... Secondary side ground 5 .......... Primary side switching circuit 51......... Primary side switch 52......... Resistor 6 .......... The first output filter circuit 61...the first inductor 62...the first capacitor 63...the second capacitor 7 ..... ..... secondary side switching circuit 71 .... first rectifying transistor 711 .... parasitic diode 8 ..... potential polarity Detection circuit 81 ... ... detection transistor 82 ... ... resistance 83 ... ... Zener diode 9 ... .... secondary side electricity Detection circuit N1 ........first winding N2........second winding 91 .... current detecting transformer 92 .... .. capacitance 93 .... first resistance 94 ... ... Zener diode 95 ... ... second resistance 96 ..... ....the first switch 97 ....the third resistor 98 ... the second switch 99 ... the third switch 10 ... ...output module 13.........second output filter power 26 M441132 way 15... •...quasi-bit shift circuit 14......second pole side switch 151... ...resistance circuit 152... •...capacitor 141 ····...second rectifying transistor 153...•...diode 1411 .·...parasitic diode 20...•...main substrate circuit
2727
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| TW101213569U TWM441132U (en) | 2012-07-13 | 2012-07-13 | Liquid crystal display product and flyback power conversion device thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI491160B (en) * | 2013-06-25 | 2015-07-01 | Top Victory Invest Ltd | Power supply without high-voltage electrolytic capacitor |
| TWI497892B (en) * | 2012-07-13 | 2015-08-21 | Tpv Electronics Fujian Co Ltd | Liquid crystal display products and its flyback power conversion device |
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2012
- 2012-07-13 TW TW101213569U patent/TWM441132U/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI497892B (en) * | 2012-07-13 | 2015-08-21 | Tpv Electronics Fujian Co Ltd | Liquid crystal display products and its flyback power conversion device |
| TWI491160B (en) * | 2013-06-25 | 2015-07-01 | Top Victory Invest Ltd | Power supply without high-voltage electrolytic capacitor |
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