1379181 九、發明說明： 【發明所屬之技術領域】 本發明係指-種用於-電源轉換器之回授控制裝置及相關方 法’尤指-種根雜電源轉換n之—次側之—伽繞阻的電壓準 位，產生一回授訊號的回授控制裝置及其相關方法。 【先前技術】 交換式電源供應器（SwitchPower Supply，SPS)主要用途乃是 將電力公司所提供的高壓、低穩定性的交流電源，轉換成適合各 種電子產品使用的低壓、穩定性較佳的直流電源，其廣泛地應用 在電腦、辦公室自動化設備、工業控制設備、通訊設備等。交換 式電源供應器的架構包含多種形式，常見如返馳式（Fly back)轉 換器、順向式（Forward)轉換器及推挽式（push_pun )轉換器等。 請參考第1圖’第1圖係一習知電源轉換器1〇的示意圖，電 源轉換器10係一返驰式電源轉換器，其包含有一變壓器1〇〇、一 開關電晶體 102、一脈寬調變（Pulse Width Modulation ’ PWM) 控制單元104、一光耦合器（Optocoupler) 106、一穩壓及誤差放 大單元108 (TL431為業界常用的型號，以下以TL431簡稱之） 及其他被動元件如電阻或電容等，在此不詳述。變壓器1〇〇包含 有 次側繞阻（Primary Winding ) NP --次側輔助繞阻 (AuxiliaryWinding) NA及一二次側繞阻（Secondary Winding)1379181 IX. Description of the invention: [Technical field of the invention] The present invention refers to a feedback control device for a power converter and a related method, which means that the hybrid power conversion n-the secondary side The voltage level of the winding generates a feedback control device for the feedback signal and related methods. [Prior Art] The main purpose of SwitchPower Supply (SPS) is to convert the high-voltage, low-stability AC power supply provided by the power company into a low-voltage, stable DC that is suitable for various electronic products. Power supply, which is widely used in computers, office automation equipment, industrial control equipment, communication equipment, etc. The architecture of the switched power supply can take many forms, such as flyback converters, forward converters, and push-pu converters. Please refer to FIG. 1 'FIG. 1 is a schematic diagram of a conventional power converter 1 ,. The power converter 10 is a flyback power converter, which comprises a transformer 1 〇〇, a switching transistor 102, and a pulse. Pulse Width Modulation 'PWM' control unit 104, an optocoupler 106, a voltage regulator and error amplifying unit 108 (TL431 is a commonly used model in the industry, hereinafter referred to as TL431) and other passive components such as Resistance or capacitance, etc., are not described in detail here. Transformer 1〇〇 includes Primary Winding NP - Auxiliary Winding NA and Secondary Winding
Ns，用來轉換能量並隔離輸入端與輸出端，以確保系統正常運作。 1379181 脈見調邊控制單70 104產生一脈波訊號，以控綱關電晶體102 的導通及關閉狀態。開關電晶體102控制變壓器100,以將整流後 之輸入電壓Vjn轉換成穩定的輪出電壓^。詳細來說，當開關 電晶體1〇2導通時’輸入電壓ViN的能量會儲存於變壓器1〇〇的一 次側繞阻Np_L ’接著，當開關電晶體1〇2關閉時，能量傳遞至二 人側、％阻Ns產生輸出電壓ν〇υτ。另外，當二次側繞阻上有 電流流動時’辅助繞阻Na會感應到輸出電壓Vqut之值。 此外’為了要穩定輸出電壓V贿，習知回授控制的作法係於 電源轉換器10的二次侧取輸出電壓ν〇υτ，經由TL431將誤差訊 號放大成為回授訊號，接著透過光耦合器106將回授訊號傳遞至 脈寬調變控制單元104以進行回授控制。當輸出電壓Vqut下降/ 上升時，脈寬調變控制單元104根據回授訊號，增大/降低控制 開關電晶體102之脈波訊號的工作週期（DutyCyde)，以增加/ 減少傳遞至二次侧負載的能量。 然而，習知透過光耦合器及TL431實現回授控制的方法，所 需要的7L件成本昂貴，亦增加電源轉換器的體積及功率消耗。因 此’習知技術另提出一一次側回授控制（primarysideFeedback C〇ntr〇1)的方法’以避免使用光耦合器及TL431。請參考第2圖， 第2圖係一習知電源轉換器2〇的示意圖。電源轉換器2〇類似於 電源轉換器1〇，其亦為一返馳式電源轉換器，包含有一變壓器 2〇〇、一開關電晶體202、一脈寬調變控制單元2〇4及其他被動元 1379181 〜 件如電阻或電容等，在此不詳述。不同的是，電源轉換器20係透 . 過輔助繞阻Na上的電壓來產生回授訊號，而不需使用光耦合器及Ns, used to convert energy and isolate the input and output to ensure the system is working properly. 1379181 The pulse-on-edge control unit 70 104 generates a pulse signal to control the turn-on and turn-off states of the transistor 102. Switching transistor 102 controls transformer 100 to convert the rectified input voltage Vjn to a stable turn-off voltage. In detail, when the switching transistor 1〇2 is turned on, the energy of the input voltage ViN is stored in the primary side winding of the transformer 1〇〇Np_L. Then, when the switching transistor 1〇2 is turned off, the energy is transferred to the two people. The side, % resistance Ns produces an output voltage ν 〇υ τ. In addition, when the current flows on the secondary winding, the auxiliary winding Na senses the value of the output voltage Vqut. In addition, in order to stabilize the output voltage V, the conventional feedback control method is based on the secondary side of the power converter 10 taking the output voltage ν 〇υ τ, and amplifying the error signal into a feedback signal via the TL431, and then transmitting the optical coupler. The feedback signal is passed to the pulse width modulation control unit 104 for feedback control. When the output voltage Vqut falls/rises, the pulse width modulation control unit 104 increases/decreases the duty cycle (DutyCyde) of the pulse signal of the control switch transistor 102 according to the feedback signal to increase/decrease the transmission to the secondary side. The energy of the load. However, it is known that the method of feedback control through the optical coupler and the TL431 requires a high cost of 7L parts and increases the size and power consumption of the power converter. Therefore, the prior art also proposes a method of primary side feedback control (primaryside feedback C〇ntr〇1) to avoid the use of an optical coupler and TL431. Please refer to FIG. 2, which is a schematic diagram of a conventional power converter 2A. The power converter 2 is similar to the power converter 1〇, which is also a flyback power converter, including a transformer 2〇〇, a switching transistor 202, a pulse width modulation control unit 2〇4, and other passive Yuan 1371181 ~ pieces such as resistors or capacitors, etc., are not detailed here. The difference is that the power converter 20 is permeable to the voltage on the auxiliary winding Na to generate the feedback signal without using an optocoupler and
TL431。當電源轉換器2〇的二次側有電流流動時，辅助繞阻NTL431. When there is current flowing on the secondary side of the power converter 2〇, the auxiliary winding N
A 會感應到輸出電壓νουτ之值，因此可據以控制脈寬調變控制單元 204，以調整控制開關電晶體202之脈波訊號的工作週期，進而調 節傳遞至二次側之負載的能量。然而，第2圖中的電源轉換器 僅為一次側回授控制的簡化示意圖，欲達成以辅助繞阻Να上的電 春壓產生回授訊號的功能，亦需要大量的元件；因此無法明顯改善 電源轉換器的體積及功率消耗。 【發明内容】 因此，本發明之主要目的即在於提供一種用於一電源轉換器之 一次側回授控制裝置及其相關方法。 本發明揭露一種用於一電源轉換器之一次側回授控制裝置，包 • 含有一控制單元，用來根據一回授訊號，產生一脈波訊號，以控 制該電源轉換器之一開關電晶體的導通及關閉狀態；一比較器， 耗接於該電源轉換器之一輔助繞阻，用來根據該輔助繞阻的電壓 準位，產生至少一控制訊號；以及一取樣保持單元，耦接於該輔 助繞阻、該比較器及該控制單元，用來根據該比較器所輸出之該 至少一控制訊號，產生該回授訊號。 本發明另揭露一種於一次側進行回授控制的電源轉換器，包含 iJ79l8l ' 有一輸入端，用來接收一輸入電壓；一輸出端，用來輸出一輸出 • 電壓，一變壓器，包含有—次側繞阻耦接於該輸入端，一輔助 繞阻耦接於該一次側繞阻，及一二次側繞阻耦接於該輸出端，用 來將該輸入電壓轉換成能量儲存於該一次側繞阻，並將該一次側 繞阻所儲存的能量傳遞至該二次側繞阻，以產生該輸出電壓；一 開關電晶體，耦接於該一次側繞阻，用來根據一脈波訊號，控制 該變壓器上的能量儲存與傳遞；以及一回授控制裝置。該回授控 φ 制裝置耦接於該開關電晶體，包含有一控制單元，用來根據一回 授訊號，產生該脈波訊號，以控制該開關電晶體的導通及關閉狀 態，一比較器，耗接於該輔助繞阻，用來根據該輔助繞阻的電壓 準位，產生至少一控制訊號；以及一取樣保持單元，耗接於該輔 助繞阻、該比較器及該控制單元，用來根據該比較器所輸出之該 至少一控制訊號，產生該回授訊號。 本發明另揭露一種用於一電源轉換器的回授控制方法，包含有 籲 根據該電源轉換器之一次側之一輔助繞阻的電壓準位，輸出一電 壓訊號；將該輔助繞阻的電壓準位與一參考電壓進行比較，以產 生一比較結果；根據該比較結果，產生至少一控制訊號；以及根 據該電壓訊號及該至少一控制訊號，產生一回授訊號，以控制該 電源轉換器之一開關電晶體。 【實施方式】 由上可知，習知透過光耦合器及TL431實現回授控制的方法， 1379181 無法節省電源轉換器的元件成本、體積及功率消耗。本發明提出 另一種一次側回授控制之電源轉換器，以節省電源轉換器的元件 成本、體積及功率消耗。 請參考第3圖，第3圖為本發明實施例一電源轉換器30之示 意圖。電源轉換器30係於一次侧進行回授控制，其包含有一輸入 端300、一輸出端3〇2、一變壓器3〇4、一開關電晶體3〇6及一回 授控制裝置308。電源轉換器30透過輸入端3〇〇接收一輸入電壓 Vin’並透過輸出端302輸出一輪出電壓ν〇υτ。變壓器304包含有 次側繞阻（Primary Winding) ΝΡ耦接於輸入端300，一輔助 繞阻（Auxiliary Winding) ΝΑ耦接於一次側繞阻νρ，以及一二次 側繞阻（Secondary Winding) Ns耦接於輸出端302，用來將輸入 電壓ViN轉換成能量儲存於一次側繞aNp，並將一次侧繞阻Np 所儲存的能量傳遞至二次側繞阻Ns，以產生輸出電壓ν〇υτ。開關 電晶體306耦接於一次側繞阻Νρ，用來根據一脈波訊號VpwM， 控制變壓器304上的能量儲存與傳遞。開關電晶體3〇6控制變壓 器304轉換能量的詳細動作，請參考前述之習知技術，在此不贅 述。回授控制裝置308耦接於開關電晶體3〇6，其包含有一分壓單 元310、一電壓隨耦器（v〇itageF〇u〇wer) 312、一比較器 (Comparator) 314、一取樣保持（Sample_and H〇w)單元 316、 一誤差放大器318及一控制單元32〇。回授控制裝置3〇8用來產生 一回授訊號，並根據回授訊號產生脈波訊號VpwM ,以控制開關電 晶體306的導通及關閉狀態。第3圖中之電壓Vc即回授訊號的電 11 1379181 壓準位。 詳細說明回授控制裝置308如下。一般來說，輔助繞阻的 電壓對其後級電路來說為高電壓，因此分壓單元31〇用來對輔助 繞阻1^八的電壓進行分壓。當輔助繞阻Να的電壓變化時，分壓單 元310所輸出的電壓vF也相應地變化。電壓隨耗器M2耗接於八 壓單元310，用來即時地根據分壓單元31〇所輪出的電壓Vf，= 出一電壓訊號至取樣保持單元316。由上可知，電壓訊號實係反應 輔助繞阻凡的電壓變化。比較器314耦接於分壓單元31〇，用來 即時地將分壓單元310所輸出的電壓Vf與一參考電壓…社進行比 較，以產生-比較結果，並根據比較結果輸出—第一控制訊號⑴ 及-第二控制訊號G2。取樣保持單元316_於電壓_器3i2 及比較S 314’用來根據電壓_器312所輸出之電壓訊號、第一 控制訊號CH及第二控制峨G2 ,產生回她號。誤差放大器318 输於取樣保持單元316及控制單元32〇之間，用來將取樣保持 單元316所輸出的回授訊號經過誤差放大，再輸出至控制單元 0控制單元32G輕接於誤差放大器318及開關電晶體獅之間， 用來根據回授5fi號產生脈波訊號VpwM，以控制開關電晶體％ 通及關閉狀態。 詳細來說’當輔助繞阻凡上的電鲜位達到—蚊電麗時， ^早兀3K)所輸出的翅％相應地達到參考糕醫。此時， 賴隨撼312將輕傳遞至取樣簡單，且比較器314 ί 12 1379181 '輸出第一控制訊號G1及第二控制訊號G2至取樣保持單元316。 ·-_取樣保持單元316根據第一控制訊號G1及第二控制訊號G2，對 電壓vF進行取樣，以產生回授訊號。換言之，回授控制裝置3⑽ 係根據辅助繞阻Να的電壓，產生回授訊號。接下來，誤差放大器 318將取樣保持單元316所輸出的回授訊號的誤差放大。最後，控 制皁το 320根據回授訊號產生脈波訊號VpwM，以控制開關電晶體 306導通及關閉狀態。 • 此外’第3圖中之分壓單元31〇包含有電阻幻、犯、一二極 體D1及一電容C3。電阻幻及幻對輔助繞阻a的電壓進行分 壓，產生電壓VF。電阻R1的一端輕接於輔助繞阻化，另一端耗 接於賴軸ϋ 312及比· 314。雜Μ的—端墟於電阻 R卜電壓隨箱器M2及比較器314，另一端輕接於一地端。二極 體D!及電容C3用來穩定電路。二極體切的負極墟於電阻幻、 電阻R2、電魏辆器312及比較器314，正極输於地端。電容 ’ C3的-端輕接於電阻R1、電阻幻、電壓隨輕器312及比較器⑽， 另一端輕接於地端。在此請注意，第3圖中之分壓單元31〇僅為 本發明之-實關，分鮮元31〇亦可财_元件組合實現。 本發明的主要目的在於根據獅触Na的賴產生浦訊號，因 =視需要蚊分壓單元31㈣存錢否及細含元件，不影響 本發明所保護的範圍。 。取樣保持單元316由至 進一步說明取樣保持單元316的運作 1379181 .:^ π關與至電容組成。請參考第4圖，第4圖亦為電源轉 •換器3〇之不意圖’與第3圖不同的是，第4圖之取樣保持單元316 進一步包含有« SW〗、SW2、電容C1及C2。關簡輕接於 電壓_器312及比較器314。開關撕輕接於比較器314、開 關SW1及誤差放大器318。電容C1的一端輕接於開關簡及撕2 之間，另一端雛於-地端。電容C2的一端輕接於開關隨及 誤差放大II 318之間’另-端祕於地端。當電源轉換器3〇的二 二欠侧繞阻①上有電流流動時，輔助繞阻na感應到輸出電壓ν〇υτ 之值，且分壓單元310對輔助繞阻乂的電壓進行分壓，產生電壓 VF。電壓馳器312即時地將電壓vF輸出至取樣保持單元316。 同時’當比較器314所產生的比較結果顯示電壓％大於參考電壓 Vref日夺’比較器314將輸出第一控制訊號⑺以控制開關隨導 通’且輸出第二控制靖;G2以控制開關SW2 _，進而將電壓 vF即時地記錄於電容c卜另-方面，當比較器314所產生的比較 結果顯示電壓VF小於或等於參考電塵Vref時，比較器训將輸出 # 第一控制訊號⑴以控制開關SW!關閉，且輸出第二控制訊號㈤ 以控制開關SW2導通’以將電容C1所儲存的電量傳遞至電容 C2。換句話說’電容C2的電壓將跟隨電容C1所記錄的電壓。由 於電容C1即時地記錄賴Vf，當開關SW1關閉且開關衝導 通時，電容C1所記錄的電磨即為膝點（Knee)電壓值。取樣保持 單元316將此膝點電壓值輸出，因此控制單元32〇可據以產生回 授訊號。 14 1379181 值付注意的疋’第3圖及第4圖中之回授控制裝置為本 '發明之實施例，本領域具通常知識者當可據以做適當的變化及修 飾。如前所述，分壓單元31G可科_元件組合實現。另一方 面’比較H 314實需触至少—控制喊。在本發明之其他實施 例中，比較器3i4可以僅輪出一控制訊號至取樣保持單元316，取 樣保持單元316透過其内部電路，自行產生所需數量的控制訊號， 如透過-反相器產生另-控制訊號。此外，取樣保持單元316所 # 包含的開關及電容可作不同的組合配置，以達成對輔助繞阻心之 膝點電壓取樣及保持的目的。因此，凡以取樣保持電路產生回授 訊號的裝置，皆應涵蓋在本發明的範圍之内。另一方面，電壓隨 耦器312及誤差放大器318可視需要決定其存在與否。請參考第5 圖至第7圖’第5圖至第7圖依序為本發明實施例電源轉換器5〇、 60及70之示意圖。電源轉換器50、60及7〇均類似於第3圖之電 源轉換器30，不同的是，電源轉換器50不包含電壓隨耦器312 及誤差放大裔318，電源轉換60不包含電壓隨輕器312 ;電源 春 轉換器不包含誤差放大器318。電源轉換器50、60及70中其 餘早元及運作皆與電源轉換器30相同，在此不贅述。 關於第4圖之電源轉換器30之相關訊號的時序波形，請同時 參考第4圖及第8圖。第8圖為電源轉換器30之相關訊號的時序 圖。第8圖中的各訊號分別為控制單元320所輸出的脈波訊號 VPWM、一次侧繞阻Np上的電流ILm、二次側繞阻Ns上的電流Is、 輔助繞阻NA的電壓VA、輔助繞，NA的電壓經過分壓單元31〇分A senses the value of the output voltage νουτ, so that the pulse width modulation control unit 204 can be controlled to adjust the duty cycle of the pulse signal for controlling the switching transistor 202, thereby adjusting the energy delivered to the secondary side load. However, the power converter in FIG. 2 is only a simplified schematic diagram of the primary side feedback control. To achieve the function of assisting the spring voltage on the winding Να to generate a feedback signal, a large number of components are also required; The volume and power consumption of the power converter. SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a primary side feedback control apparatus for a power converter and related methods. The present invention discloses a primary side feedback control device for a power converter, comprising: a control unit for generating a pulse signal according to a feedback signal to control a switching transistor of the power converter And a comparator, consuming one of the auxiliary windings of the power converter for generating at least one control signal according to the voltage level of the auxiliary winding; and a sample and hold unit coupled to the The auxiliary winding, the comparator and the control unit are configured to generate the feedback signal according to the at least one control signal output by the comparator. The invention further discloses a power converter for performing feedback control on a primary side, comprising an iJ79l8l 'having an input for receiving an input voltage; an output for outputting an output voltage, a transformer, including - The side winding is coupled to the input end, an auxiliary winding is coupled to the primary side winding, and a secondary side winding is coupled to the output end for converting the input voltage into energy for storage. a side winding, and transferring the energy stored in the primary side winding to the secondary side winding to generate the output voltage; a switching transistor coupled to the primary side winding for using a pulse wave A signal that controls the storage and transfer of energy on the transformer; and a feedback control device. The feedback control φ device is coupled to the switch transistor, and includes a control unit for generating the pulse signal according to a feedback signal to control the on and off states of the switch transistor, a comparator, The auxiliary winding is used to generate at least one control signal according to the voltage level of the auxiliary winding; and a sampling and holding unit is used for the auxiliary winding, the comparator and the control unit, and is used for The feedback signal is generated according to the at least one control signal output by the comparator. The present invention further discloses a feedback control method for a power converter, comprising: calling a voltage level according to one of the primary sides of the power converter to output a voltage signal; and outputting the voltage of the auxiliary winding Comparing a level with a reference voltage to generate a comparison result; generating at least one control signal according to the comparison result; and generating a feedback signal according to the voltage signal and the at least one control signal to control the power converter One of the switching transistors. [Embodiment] As can be seen from the above, the conventional method of implementing feedback control through the optical coupler and the TL431, 1379181 cannot save the component cost, volume, and power consumption of the power converter. The present invention proposes another power converter for primary side feedback control to save component cost, size and power consumption of the power converter. Please refer to FIG. 3, which is a schematic diagram of a power converter 30 according to an embodiment of the present invention. The power converter 30 is provided with feedback control on the primary side, and includes an input terminal 300, an output terminal 3, a transformer 3〇4, a switching transistor 3〇6, and a feedback control device 308. The power converter 30 receives an input voltage Vin' through the input terminal 3'' and outputs a round-out voltage ν〇υτ through the output terminal 302. The transformer 304 includes a primary winding (ΝΡ) coupled to the input terminal 300, an auxiliary winding (Auxiliary Winding) coupled to the primary winding νρ, and a secondary winding (Nedical Winding) Ns The output terminal 302 is coupled to convert the input voltage ViN into energy to be stored in the primary side winding aNp, and transfer the energy stored in the primary side winding Np to the secondary side winding Ns to generate an output voltage ν〇υτ . The switch transistor 306 is coupled to the primary side winding Νρ for controlling energy storage and transfer on the transformer 304 based on a pulse signal VpwM. The switching transistor 3〇6 controls the detailed operation of the transformer 304 to convert energy. Please refer to the above-mentioned prior art and will not be described here. The feedback control device 308 is coupled to the switching transistor 3〇6, and includes a voltage dividing unit 310, a voltage follower 312, a comparator 314, and a sample hold. (Sample_and H〇w) unit 316, an error amplifier 318, and a control unit 32A. The feedback control device 3〇8 is used to generate a feedback signal, and generates a pulse signal VpwM according to the feedback signal to control the on and off states of the switching transistor 306. The voltage Vc in Fig. 3 is the voltage of the feedback signal 11 1379181. The feedback control device 308 will be described in detail as follows. Generally, the voltage of the auxiliary winding is a high voltage for its subsequent stage circuit, so the voltage dividing unit 31 is used to divide the voltage of the auxiliary winding 1^8. When the voltage of the auxiliary winding Να changes, the voltage vF output from the voltage dividing unit 310 also changes accordingly. The voltage follower M2 is connected to the eight-voltage unit 310 for instantaneously outputting a voltage signal to the sample-and-hold unit 316 according to the voltage Vf rotated by the voltage dividing unit 31. As can be seen from the above, the voltage signal is actually a reaction that assists in the winding of the voltage change. The comparator 314 is coupled to the voltage dividing unit 31A for instantaneously comparing the voltage Vf outputted by the voltage dividing unit 310 with a reference voltage to generate a comparison result, and outputting according to the comparison result - the first control Signal (1) and - second control signal G2. The sample holding unit 316_ is used to generate the return number according to the voltage signal, the first control signal CH and the second control 峨G2 outputted by the voltage _ 312. The error amplifier 318 is input between the sample and hold unit 316 and the control unit 32A, and is used for error amplification of the feedback signal outputted by the sample and hold unit 316, and then outputted to the control unit 0. The control unit 32G is connected to the error amplifier 318 and Between the switching transistor lions, the pulse signal VpwM is generated according to the feedback 5fi to control the switching transistor % pass and off state. In detail, when the auxiliary electric winding reaches the electric fresh position, the mosquito output is as follows. At this time, the Lai 撼 312 transfers the light to the sampling is simple, and the comparator 314 ί 12 1379181 ' outputs the first control signal G1 and the second control signal G2 to the sample holding unit 316. The sample holding unit 316 samples the voltage vF based on the first control signal G1 and the second control signal G2 to generate a feedback signal. In other words, the feedback control device 3 (10) generates a feedback signal based on the voltage of the auxiliary winding Να. Next, the error amplifier 318 amplifies the error of the feedback signal output from the sample holding unit 316. Finally, the control soap το 320 generates a pulse signal VpwM according to the feedback signal to control the switching transistor 306 to be turned on and off. • In addition, the voltage dividing unit 31〇 in Fig. 3 includes a resistor illusion, a dyad, a diode D1, and a capacitor C3. The resistor phantoms and phantoms divide the voltage of the auxiliary winding a to generate a voltage VF. One end of the resistor R1 is lightly connected to the auxiliary winding, and the other end is consumed by the yaw axis 312 and the ratio 314. The chowder-end-end is in the resistance R Bu voltage with the box M2 and the comparator 314, and the other end is lightly connected to a ground end. Diode D! and capacitor C3 are used to stabilize the circuit. The negative electrode cut by the diode is in the resistor phantom, the resistor R2, the electric Wei 312 and the comparator 314, and the anode is sent to the ground. The end of the capacitor 'C3 is lightly connected to the resistor R1, the resistor phantom, the voltage follower 312 and the comparator (10), and the other end is lightly connected to the ground. Please note that the voltage dividing unit 31 in Fig. 3 is only the real-time of the present invention, and the new unit 31 can also be realized by a combination of components. The main object of the present invention is to generate a Pu signal according to the lion's touch, because the mosquito-removing unit 31 (4) saves money and contains components, and does not affect the scope of protection of the present invention. . The sample-and-hold unit 316 is further configured to further describe the operation of the sample-and-hold unit 316 1379181 . Please refer to FIG. 4, and FIG. 4 is also a schematic diagram of the power converter 3'. In contrast to FIG. 3, the sample-and-hold unit 316 of FIG. 4 further includes «SW〗, SW2, and capacitor C1. C2. The switch is lightly connected to the voltage _ 312 and the comparator 314. The switch is lightly connected to the comparator 314, the switch SW1 and the error amplifier 318. One end of the capacitor C1 is lightly connected between the switch and the tear 2, and the other end is at the ground end. One end of the capacitor C2 is lightly connected to the switch and the error amplification II 318 is between the other end and the end is secret. When a current flows through the two-side under-side winding 1 of the power converter 3〇, the auxiliary winding na induces a value of the output voltage ν〇υτ, and the voltage dividing unit 310 divides the voltage of the auxiliary winding 乂, A voltage VF is generated. The voltage hopper 312 instantaneously outputs the voltage vF to the sample hold unit 316. At the same time, when the comparison result generated by the comparator 314 shows that the voltage % is greater than the reference voltage Vref, the comparator 314 will output the first control signal (7) to control the switch to conduct and output the second control; G2 to control the switch SW2 _ And in turn, the voltage vF is recorded in the capacitor c. In other words, when the comparison result generated by the comparator 314 indicates that the voltage VF is less than or equal to the reference electric dust Vref, the comparator trains the output #1 control signal (1) to control The switch SW! is turned off, and the second control signal (5) is output to control the switch SW2 to conduct 'to transfer the amount of power stored by the capacitor C1 to the capacitor C2. In other words, the voltage of capacitor C2 will follow the voltage recorded by capacitor C1. Since the capacitor C1 records the Vf immediately, when the switch SW1 is turned off and the switch is turned on, the electric grinder recorded by the capacitor C1 is the Knee voltage value. The sample hold unit 316 outputs the knee voltage value, so that the control unit 32 can generate a feedback signal accordingly. 14 1379181 Value-paying 疋 'The feedback control device in Figures 3 and 4 is an embodiment of the invention, and those of ordinary skill in the art can make appropriate changes and modifications as appropriate. As described above, the voltage dividing unit 31G can be implemented in a combination of components. On the other hand, 'Comparative H 314 needs to touch at least—control shouts. In other embodiments of the present invention, the comparator 3i4 may only rotate a control signal to the sample and hold unit 316. The sample and hold unit 316 generates a desired number of control signals through its internal circuit, such as a trans-inverter. Another - control signal. In addition, the switches and capacitors included in the sample holding unit 316 can be configured in different combinations to achieve the purpose of sampling and maintaining the knee voltage of the auxiliary winding. Therefore, any device that generates a feedback signal by the sample and hold circuit should be covered by the scope of the present invention. On the other hand, voltage coupler 312 and error amplifier 318 can determine their presence or absence as needed. Please refer to FIG. 5 to FIG. 7 ' FIGS. 5 to 7 for a schematic diagram of power converters 5 〇 , 60 and 70 according to an embodiment of the present invention. The power converters 50, 60, and 7 are similar to the power converter 30 of FIG. 3, except that the power converter 50 does not include the voltage follower 312 and the error amplification 318, and the power conversion 60 does not include voltage with light. The power spring converter does not include an error amplifier 318. The rest of the power converters 50, 60, and 70 are the same as the power converter 30, and will not be described here. For the timing waveform of the related signal of the power converter 30 of Fig. 4, please refer to Fig. 4 and Fig. 8 at the same time. Figure 8 is a timing diagram of the associated signals of power converter 30. The signals in FIG. 8 are respectively the pulse signal VPWM outputted by the control unit 320, the current ILm on the primary side winding Np, the current Is on the secondary side winding Ns, the voltage VA of the auxiliary winding NA, and the auxiliary. Winding, the voltage of NA is divided by the voltage dividing unit 31
15 1379181 壓之後的電壓vF、第一控制訊號⑴、第二控制訊號G2、電愿隨 ' 耦器312所輸出的電壓訊號Va、電容C1的電壓％以及電容€2 的電壓Vc。由第8圖可知，輔助繞阻Na的電壓Va的膝點電壓為 VOUTx(Ns/NA) ’分壓單元31〇所輪出之電壓％的膝點電壓為v⑽ x(Ns/Na)xR2/(R1+R2)(如第8圖中箭頭所示位置），且電容α記 錄電壓VF，電容C2記錄電壓VF的膝點電壓，以達成對電壓 的膝點電壓進行取樣及保持的目的。各訊號的動作參考前述可 _ 知，於此不贅述。 除此之外’睛參考第9圖’第9圖本發明之實施例一流程9〇 之示意圖。流程90為第3圖中電源轉換器3〇之操作流程，其包 含下列步驟： 步驟900 :開始。 步驟902 :分壓單元310將該電源轉換器之一次側之一輔助繞 阻的電壓進行分壓，以產生一分壓訊號。 • 步驟904:電壓隨耦器312根據該分壓訊號，輸出一電壓訊號。 步驟906 :比較器314將該分壓訊號的電壓與一參考電壓進行 比較，以產生一比較結果。 步驟908 :比較器314根據該比較結果，產生一第一控制訊號 及一第二控制訊號。 步驟910 :取樣持單元316根據該電壓訊號、該第一控制訊號 及該第二控制訊號，產生一回授訊號。 步驟912 :誤差放大器318將該回授訊號的誤差放大。 1379181 :^驟914控制單元320根據該回授訊號，產生一脈波訊號， ' 以控制該電源轉換器之一開關電晶體的導通及關閉 狀態。 步驟916 :結束。 關於流程90的詳細運作，請參考前述之電源轉換器3〇，在此 不贅述。值得注意的是，流程9〇為本發明之一實施例，本領域具 ^ 通常知識者當可據以做不同的變化及修飾。舉例來說，若電源轉 換器30不包含電壓隨耦器312，則步驟904可省略；若電源轉換 器30不包含誤差放大器318，則步驟912可省略。除此之外第 4圖之取樣保持單元316包含之開關SW卜SW2、電容C1及C2， 其僅為本發明之一實施例，流程9〇的應用不受限於取樣持單元 316所包含之元件。另一方面，由於比較器314實需產生至少一控 制訊號，在本發明之其他實施例中，比較器314可以根據比較結 果，僅產生一控制訊號。取樣保持單元316透過其内部電路自 鲁 行產生所需數量的控制訊號。 綜上所述，本發明之回授控制裝置係位於電源轉換器之一次 側，透過比較ϋ及取樣保持單元’記_助繞阻之膝點電獅為 回授訊號。@此，本發明不光耦合^及^^即可實現回 授控制，進而節省電源轉換器的元件成本、體積及功率消耗。 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範 17 1379181 圍所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第1圖及第2圖為習知電源轉換器之示意圖。 第3圖至第7圖為本發明實施例電源轉換器之示意圖。 第8圖為第4圖之電源轉換器的相關訊號之時序圖。 第9圖為本發明實施例一流程之示意圖。 【主要元件符號說明】 10、20、30、50、60、70 電源轉換器 100、200、304 變壓器 . 102、202、306 開關電晶體 104、204 脈寬調變控制單元 106 光耦合器 108 穩壓及誤差放大單元 300 輸入端 302 輸出端 308 回授控制裝置 310 分壓單元 312 電壓隨耦器 314 比較器 316 取樣保持單元 318 誤差放大器 18 137918115 1379181 The voltage vF after the voltage, the first control signal (1), the second control signal G2, the voltage signal Va outputted by the 'coupler 312, the voltage % of the capacitor C1, and the voltage Vc of the capacitor €2. As can be seen from Fig. 8, the knee voltage of the voltage Va of the auxiliary winding Na is VOUTx (Ns/NA). The knee voltage of the voltage % which is divided by the voltage dividing unit 31 is v(10) x(Ns/Na)xR2/ (R1+R2) (as indicated by the arrow in Fig. 8), and the capacitance α records the voltage VF, and the capacitance C2 records the knee voltage of the voltage VF to achieve the purpose of sampling and holding the knee voltage of the voltage. The operation of each signal is referred to the foregoing, and will not be described here. In addition, the "eyes refer to Fig. 9" Fig. 9 is a schematic view of the flow of the first embodiment of the present invention. The process 90 is the operation flow of the power converter 3 in FIG. 3, which includes the following steps: Step 900: Start. Step 902: The voltage dividing unit 310 divides the voltage of the auxiliary winding of one of the primary sides of the power converter to generate a voltage dividing signal. • Step 904: The voltage follower 312 outputs a voltage signal according to the voltage dividing signal. Step 906: The comparator 314 compares the voltage of the voltage dividing signal with a reference voltage to generate a comparison result. Step 908: The comparator 314 generates a first control signal and a second control signal according to the comparison result. Step 910: The sampling holding unit 316 generates a feedback signal according to the voltage signal, the first control signal and the second control signal. Step 912: The error amplifier 318 amplifies the error of the feedback signal. 1379181: The control unit 320 generates a pulse signal according to the feedback signal, to control the on and off states of the switching transistor of the power converter. Step 916: End. For the detailed operation of the process 90, please refer to the aforementioned power converter 3〇, which will not be described here. It should be noted that the process 9 is an embodiment of the present invention, and those skilled in the art can generally make different changes and modifications. For example, if power converter 30 does not include voltage follower 312, step 904 may be omitted; if power converter 30 does not include error amplifier 318, step 912 may be omitted. In addition, the sample holding unit 316 of FIG. 4 includes the switch SW, the capacitors C1 and C2, which are only one embodiment of the present invention, and the application of the process 9〇 is not limited to the inclusion of the sample holding unit 316. element. On the other hand, since the comparator 314 is required to generate at least one control signal, in other embodiments of the present invention, the comparator 314 can generate only one control signal based on the comparison result. The sample and hold unit 316 generates the required number of control signals by its internal circuitry. In summary, the feedback control device of the present invention is located on the primary side of the power converter, and is a feedback signal through the comparison ϋ and the sample holding unit _ @This, the present invention can realize feedback control without optical coupling and ^^, thereby saving component cost, volume and power consumption of the power converter. The above is only the preferred embodiment of the present invention, and all changes and modifications made in accordance with the scope of the present application are subject to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are schematic views of a conventional power converter. 3 to 7 are schematic views of a power converter according to an embodiment of the present invention. Figure 8 is a timing diagram of the related signals of the power converter of Figure 4. FIG. 9 is a schematic diagram of a process of an embodiment of the present invention. [Main component symbol description] 10, 20, 30, 50, 60, 70 power converter 100, 200, 304 transformer. 102, 202, 306 switching transistor 104, 204 pulse width modulation control unit 106 optical coupler 108 stable Voltage and error amplifying unit 300 Input terminal 302 Output terminal 308 Feedback control device 310 Voltage dividing unit 312 Voltage follower 314 Comparator 316 Sample holding unit 318 Error amplifier 18 1379181
320 控制單元 NP 一次侧繞阻 Ns 二次側繞阻 Na 輔助繞阻 V,n 輸入電壓 V〇UT 輸出電壓 G1 第一控制訊號 G2 第二控制訊號 SW1 ' SW2 開關 Cl > C2 > C3 電容 R1 ' R2 電阻 D1 二極體 VpwM 脈波訊號 ILm、Is 電流 VA ' VF ' Va > Vb 'Vc 電壓 Vref 參考電壓 90 流程 900、902、904、906、908、910、912、914、916 步驟320 Control Unit NP Primary Side Winding Ns Secondary Side Winding Na Auxiliary Winding V, n Input Voltage V〇UT Output Voltage G1 First Control Signal G2 Second Control Signal SW1 'SW2 Switch Cl > C2 > C3 Capacitor R1 ' R2 Resistor D1 Diode VpwM Pulse Signal ILm, Is Current VA ' VF ' Va > Vb 'Vc Voltage Vref Reference Voltage 90 Flow 900, 902, 904, 906, 908, 910, 912, 914, 916 Steps