1380151 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H之可動態控制參考電壓之 -次側回授控制裝置及_方法’尤指—種根據該電轉換器之 一回授訊號，產生-參考電壓的-次侧回授控制裝置及其相關方 法。 【先前技術】 父換式電源供應器（Switch Power 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七ack)轉 換器、順向式（Forward )轉換器及推挽式（Push-Pull)轉換器等。 請參考第1圖，第1圖為一習知電源轉換器10的示意圖，電 源轉換器10係一返馳式電源轉換器，其包含有一變壓器1〇〇、一 開關電晶體 102、一脈寬調變（PulseWidthModulation，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100包含 有--次側繞阻（Primary Winding ) NP、一一次側輔助繞阻 (Auxiliary Winding ) NA 及一二次侧繞阻（Secondary Winding ) δ1380151 IX. Description of the invention: [Technical field of the invention] The present invention refers to a sub-back feedback control device and a method for dynamically controlling a reference voltage for power conversion H, and One of the converters returns a signal, a - reference voltage-sub-back feedback control device and related methods. [Prior Art] The main purpose of Switch Power Supply ' SPS is to convert the high voltage and low stability AC power provided by the power company into low voltage and good stability suitable for various electronic products. The DC power supply is widely used in computers, office automation equipment, industrial control equipment, communication equipment, and the like. The architecture of the switched power supply can take many forms, such as a flyback (Fly seven ack) converter, a forward converter, and a push-pull converter. Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a conventional power converter 10 . The power converter 10 is a flyback power converter including a transformer 1 , a switching transistor 102 , and a pulse width. Pulse Width Modulation (PWM) control unit 104, an optocoupler (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 resistors or capacitors Etc., not detailed here. The transformer 100 includes a Primary Winding NP, an Auxiliary Winding NA, and a Secondary Winding δ.
138UIM138UIM
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。 脈寬調變控制單7G 1G4產生—脈波訊號，以控糊關電晶體⑽ ，導通及關閉狀態1開關電晶體1G2導通時，輪人電壓〜的能 量會儲存於變麵1〇〇的-次側繞阻Np上；當開關電晶體1〇2關 閉時’能量傳遞至二次側繞阻Ns，產生輸出_ 。當二次侧 繞阻NS上有電流流動時’輔助繞阻乂會感應到輸㈣壓之 值。 此外’為了要穩錄出電壓V贿，f知回授控制的作法係於 電源轉換㈣的二次麻獅輕Vqut，_ TU3i將誤差訊 號放大成相授訊號，接著_紐合^ 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V〇UT下降/ 上升時脈寬調邊控制單元1〇4根據回授訊號增^^健綱 關電晶體102之脈波訊號的卫作職（DutyCyde)，以增加/減少 傳遞至一-人側負載的▲量。然而，習知透過光輕合器及几州實 見回授控制的方法’所需要的元件成本昂貴，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（PrimarySideNs ' is used to convert energy and isolate the input and output to ensure proper system operation. Pulse width modulation control 7G 1G4 generates pulse signal to control the paste transistor (10), turn on and off state 1 When the switch transistor 1G2 is turned on, the energy of the wheel voltage ~ will be stored in the variable surface 1〇〇- The secondary side is wound on Np; when the switching transistor 1〇2 is turned off, 'energy is transferred to the secondary side winding Ns, and an output _ is generated. When there is current flowing on the secondary side winding NS, the auxiliary winding resistance will sense the value of the input (four) voltage. In addition, in order to stably record the voltage V bribe, the method of feedback control is based on the secondary lion light Vqut of the power conversion (4), _ TU3i amplifies the error signal into a phase-coordinate signal, and then _ _ ^ will be feedback The signal is passed to the pulse width modulation control unit 104 for feedback control. When the output voltage V〇UT falls/rises, the pulse width adjustment control unit 1〇4 increases/decreases to the duty signal of the pulse signal of the transistor 102 according to the feedback signal (DutyCyde). One - the amount of ▲ of the human side load. However, it is known that the components required by the optical coupling and the method of feedback control in several states are expensive, and the volume and power consumption of the power converter are also increased. Therefore, the prior art also proposes a one-time feedback control (PrimarySide)
Feedbaek〇)ntr()1)的方法’以避免使用光搞合器及TL43卜請參 考第2圖’第2圖為-f知電源轉換H 2㈣示意圖。電源轉換器 2〇類似於電源轉換器10’其亦為一返馳式電源魏器，包含有一 變壓器200、-開關電晶體2〇2、一脈寬調變控制單元2〇4及其他 \%ί 9 1380151 被動元件如電阻或電容等，在此不詳述。不同的是，電源轉換器 20係透過輔助繞阻凡上的電壓來產生回授訊號，而不需使用光 耦合器及TL431。當電源轉換器2〇的二次侧有電流流動時，辅助 %阻>^會感應到輸出電廢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2〇2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20僅為一次側回授控制的簡化示意圖，欲達成以輔助繞 阻NA1的電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。 為了改善一次側回授控制需要大量元件的缺點，本案發明人 已提出一種具有易於實現的一次側回授控制裝置之電源轉換器， 請參考第3圖。第3圖為一電源轉換器3〇的示意圖。電源轉換器 30類似於前述之電源轉換器2〇，關於電源轉換器3〇之一次側中 的元件及回授控制的運作’請參考前述，在此不贅述。在此請注 意，電源轉換器30所包含之一回授控制裝置3〇8不同於習知回授 控制襄置。簡言之，回授控制裝置3〇8包含有一控制單元31〇、一 比較器312及一取樣保持單元314。比較器312搞接於電源轉換器 30之一辅助繞阻NA，用來根據輔助繞阻Na的電壓準位及一預先 設計之固定參考電壓Vref，產生控制訊號，以控制取樣保持單元 314輪出一回授訊號至控制單元310。控制單元31〇根據回授訊號 產生脈波訊號VPWM，以控制一開關電晶體306的導通及關閉狀 〜、進而調節傳遞至二次側之負載的能量。相較於習知技術，回 1380151 授控制裝置308具有實現簡單的優點。 值得注意岐…般電_換闕機時，f感電容效應會影 響輔助繞阻的電壓，產生電壓震盪現象。在電壓震盪大的情^ 下’若電源轉換器3G中的參考電壓Vrcf—開始即低於回授月訊號的 電壓準位且無法改變，取樣保持單元3〇6後續所輸出的回授訊號 將文電壓震if彡響而制降低。如此_來，根據回授訊號所產生 的脈波訊號VPWM可能無法驅動開關電晶體306。 由上可知，習知透過光耦合器及TL431實現回授控制的方法， 無法節省電職換器的元件成本、體積及功率消耗。另一方面， 本案發明人所提出之—次湘授控制之電轉換器雖可節省元件 成本及功率雜’但無法避免回授訊號受電源轉換關機時的電 壓震盪現象所影響。 【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 可動態控制參考電壓之-次_授控織置及其相關方法。 本發明揭露__於—電源轉換器之可祕控制參考電壓之 -次側回授控雛置’包含有—控制單元，用絲據—回授訊號， 產生-脈波職，啸繼魏轉換器之__電晶體的導通及 關閉狀態；-峨H 於該電源轉換器之—輔助繞阻，用來 11 1380151 根據該輔助繞阻的電壓準位及一參考電壓，產生至少一控制訊 號，-取樣鋪單TL ’轉於該獅繞阻、該味器及該控制單 元’絲根據該比較ϋ所輸出之該至少-㈣訊號，產生該回授 •訊號；以及一參考電壓產生器，搞接於該控制單元、該比較器及 .該取樣保持單元’用來根據該回授訊號，產生該比較器所使用之 . 該參考電壓。 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 有-輸入端，用來接收-輸入電漫；一輸出端，用來輸出一輸出 電壓，-變壓器，包含有一一次侧繞阻輕接於該輸入端，一輔助 繞阻搞接於該-次側繞阻，及一二次侧繞阻雛於該輸出端用 來將該輸人賴轉換成能量儲存於該—次纖阻，並將該一次側 繞阻所儲存的能量傳遞至該二次侧繞阻，以產生該輸出電壓；一 開關電晶體，墟於該-次側繞阻，用來根據—脈波訊號，控制 該變廢器上量儲存與傳遞；以及—可域控制參考電麼之回 籲授控制裝置。該可動態控制參考電壓之回授控制裝置稱接於該開 關電晶體’包含有-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；—比較器，耦 接於該輔助繞阻，用來根據該輔助繞阻的電壓準位及一參考電 壓’產生至少-控制訊號；一取樣保持單元，搞接於該輔助繞阻、 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，號’產生該回授訊號；以及一參考賴產生器，麵接於該^ 制單元、該比較器及該取樣保持單元，用來根據該回授訊號，產 12 1380151 生該比較器所使用之該參考電壓。 本發明另揭露-種祕—電轉換㈣回授鋪方法，包含 -根據該電源轉換11之—次側之-輔助繞阻的電壓準位，輸出一電 •壓訊號，根據-峨訊號，產生—參考電壓；將糊助繞阻的電 準位與該參考電壓進行比較，以產生一錄結果；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 鲁制=號產生回授訊號，以控制該電源轉換器之一開關電晶體。 【實施方式】 «月參考第4圖，第4圖為本發明實施例一電源轉換器4〇之示 意® °電源轉換H 4G係於-次側進行回授控制，其包含有一輸入 端400、一輸出端402 ' —變壓器4〇4、一開關電晶體406及一回 授控制裝置408。電源轉換器40透過輸入端400接收一輸入電壓 ViN ’並透過輸出端402輸出一輸出電壓ν〇υτ。變壓器304包含有 # 次側繞阻（Primary Winding ) ΝΡ耦接於輸入端4〇〇，一輔助 繞阻（Auxihaiy 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402，用來將輸入 電壓乂似轉換成能量儲存於一次側繞阻^^，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406耦接於一次側繞阻Νρ，用來根據一脈波訊號VpwM , 控制變壓器404上的能量儲存與傳遞。開關電晶體406控制變壓 器404轉換能量的詳細動作，請參考前述之習知技術，在此不贅 13 1380151 述。回授控制裝置408耦接於開關電晶體4〇6，其包含有一分壓單 元410 電屬隨搞器（V〇丨tage Follower) 412、一比較器 (C〇mparat〇r) 414、一取樣保持（Sample-and-Hold)單元 416、 -一誤差放大器418、一控制單元及-參考電壓產生器422。回 -授控制裝置408帛來產生-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406的導通及關閉狀態。 詳細說明回授控制裝置408如下。一般來說，辅助繞阻NA的 攀電壓對其後級電路來說為高電壓，因此分壓單元用來對輔助 繞阻na的賴進行分壓。當獅繞阻Na的職變化時，分壓單 兀410所輸出的電壓Vf也相應地變化。電壓隨耦器412耦接於分 壓單元410，用來即時地根據分壓單元41〇所輸出的電壓Vp，輸 出-電壓訊號至取樣保持單元416。由上可知，電壓訊號實係反應 輔助繞阻>^的電壓變化。比較器414耦接於分壓單元41〇，用來 即時地將分壓單元410所輸出的電壓Vf與一參考電壓Vref進行比 #較’以產生一比較結果，並根據比較結果輸出-第-控制訊號G1 及一第二控制訊號G2。取樣保持單元416耦接於電壓隨耦器4i2 及比較器414，用來根據電壓隨耦器412所輸出之電壓訊號、第一 控制訊號G1及第二控制訊號G2，產生回授訊號。同時，U回授訊 號回授至參考電壓產生器422。誤差放大器418 _接於取樣保持單 元仙及控制單元42〇之間，用來將取樣保持單元仙所輸出的 回授訊號經過誤差放大，再輸出至控制單元42〇。控制單元42〇 祕於誤差放大器4職開關電晶體406之間，用來根據回授訊 1380151 號產生脈波減vPWM ’以控制開關電晶體4〇6導通及關閉狀態。 參考電壓產生器422耦接於控制單元42〇、比較器414及取樣保持 單元416 ’用來根據回授訊號，產生比較器414所使用之參考電壓 Vref。 由上可知，參考電壓Vref不是固定的電壓，而是根據回授訊號 所產生。如此_來’於電轉換^職造成電壓震盪時，本發明 實施例彈性地樹細授概，控师考電壓醫社小，以避免 取樣保持單το 416後續產生之回授訊號的電壓，受震盪影響而持 續降低。更進-步地，本發明提出兩個實施例，一為參考電壓㈣ 等於回授喊之電鮮⑽—H]定倍數；另__為參考電壓醫等 於回授訊號之電壓準位的-可變倍數。換言之，若回授訊號之電 壓準位以Ve表示，參考Vref射相應表示細％，其中係 數α可為常數，亦可為變數。α為變數的應用將敘述如後。Feedbaek〇)ntr()1) method 'to avoid using the light combiner and TL43, please refer to Figure 2'. Figure 2 shows the -f power conversion H 2 (four) diagram. The power converter 2 is similar to the power converter 10'. It is also a flyback power transmitter, including a transformer 200, a switching transistor 2〇2, a pulse width modulation control unit 2〇4, and other \% ί 9 1380151 Passive components such as resistors or capacitors are not detailed here. The difference is that the power converter 20 generates a feedback signal by applying a voltage across the auxiliary winding without using an optical coupler and the TL431. When there is current flowing on the secondary side of the power converter 2, the auxiliary % resistance > will sense the value of the output power waste νουτ, so that the pulse width modulation control unit 204' can be controlled to adjust the control switch transistor. The duty cycle of the pulse signal of 2〇2, which in turn adjusts the energy delivered to the load on the secondary side. However, the power converter 20 in FIG. 2 is only a simplified schematic diagram of the primary side feedback control. To achieve the function of assisting the voltage of the winding NA1 to generate the feedback signal, a large number of components are also required, so that the power conversion cannot be significantly improved. Volume and power consumption. In order to improve the disadvantages of requiring a large number of components for the primary side feedback control, the inventors of the present invention have proposed a power converter having an easy-to-implement primary-side feedback control device, please refer to FIG. Figure 3 is a schematic diagram of a power converter 3〇. The power converter 30 is similar to the power converter 2〇 described above, and the operation of the components and the feedback control in the primary side of the power converter 3' is referred to the foregoing, and will not be described herein. It should be noted here that one of the feedback control devices 3〇8 included in the power converter 30 is different from the conventional feedback control device. In short, the feedback control device 〇8 includes a control unit 31, a comparator 312, and a sample hold unit 314. The comparator 312 is connected to an auxiliary winding NA of the power converter 30 for generating a control signal according to the voltage level of the auxiliary winding Na and a pre-designed fixed reference voltage Vref to control the sampling and holding unit 314 to rotate. A feedback signal is sent to the control unit 310. The control unit 31 generates a pulse signal VPWM according to the feedback signal to control the conduction and closing of a switching transistor 306, thereby adjusting the energy transmitted to the load on the secondary side. Compared to the prior art, the control device 308 is returned to the 1380151 with the advantage of being simple to implement. It is worth noting that...when the electric machine is changed, the capacitive effect of the f senses the voltage of the auxiliary winding and generates a voltage oscillation. In the case of a large voltage oscillation, if the reference voltage Vrcf in the power converter 3G is lower than the voltage level of the feedback monthly signal and cannot be changed, the subsequent feedback signals output by the sample and hold unit 3〇6 will be The voltage of the voltage is reduced and the system is reduced. Thus, the pulse signal VPWM generated according to the feedback signal may not be able to drive the switching transistor 306. It can be seen from the above that the method of implementing feedback control through the optical coupler and the TL431 can not save the component cost, volume and power consumption of the electric service. On the other hand, the electric converter controlled by the inventor of the present invention can save component cost and power miscellaneously, but cannot avoid the influence of the voltage oscillation phenomenon when the feedback signal is turned off by the power conversion. SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a sub-control woven and a related method for dynamically controlling a reference voltage for a power converter. The invention discloses the secret control reference voltage of the power converter - the secondary side feedback control mode includes the - control unit, uses the wire data - the feedback signal, generates the pulse wave, and the Wei Weiwei conversion __The transistor is turned on and off; -峨H is the auxiliary winding of the power converter, and 11 1380151 generates at least one control signal according to the voltage level of the auxiliary winding and a reference voltage. - the sampling shop TL 'transfers to the lion winding, the odour and the control unit's output the feedback signal according to the at least - (four) signal output by the comparison ;; and a reference voltage generator Connected to the control unit, the comparator, and the sample holding unit 'for generating the reference voltage used by the comparator according to the feedback signal. The invention further discloses a power converter for performing feedback control on a primary side, comprising an input terminal for receiving-input electric diffuser, an output terminal for outputting an output voltage, and a transformer comprising a primary side winding The light is connected to the input end, an auxiliary winding is connected to the secondary side winding, and a secondary side winding is used at the output end to convert the input to energy to be stored in the secondary fiber Resisting, and transferring the energy stored in the primary side winding to the secondary side winding to generate the output voltage; a switching transistor, in the secondary side winding, is used according to the pulse signal, Controlling the amount of storage and transfer of the waste device; and - the domain control reference device is returned to the control device. The feedback control device capable of dynamically controlling the reference voltage is connected 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. The comparator is coupled to the auxiliary winding for generating at least a control signal according to the voltage level of the auxiliary winding and a reference voltage; a sample holding unit that engages the auxiliary winding, the comparison And the control unit, configured to generate the feedback signal according to the at least one control output by the comparator; and a reference generator connected to the control unit, the comparator, and the sample hold The unit is configured to generate the reference voltage used by the comparator according to the feedback signal. The invention further discloses a secret-electrical conversion (four) feedback laying method, comprising: according to the voltage level of the secondary side-auxiliary winding of the power conversion 11, outputting an electric pressure signal, according to the -峨 signal, generating a reference voltage; comparing the electrical level of the paste-assisted winding with the reference voltage to generate a recorded result; generating at least one control signal according to the comparison result; and according to the voltage signal and the at least one control system= The number generates a feedback signal to control one of the switching transistors of the power converter. [Embodiment] «Monthly reference to FIG. 4, FIG. 4 is a schematic diagram of a power converter 4 ® according to the embodiment of the present invention. The power conversion H 4G is connected to the secondary side for feedback control, and includes an input terminal 400. An output terminal 402' - a transformer 4 〇 4, a switching transistor 406 and a feedback control device 408. The power converter 40 receives an input voltage ViN' through the input terminal 400 and outputs an output voltage ν〇υτ through the output terminal 402. The transformer 304 includes #Primary Winding ΝΡ coupled to the input terminal 4〇〇, an auxiliary winding (Auxihaiy Winding) ΝΑ coupled to the primary winding Νρ, and a secondary winding (Secondary) Winding) Ns is coupled to the output terminal 402 for converting the input voltage into energy and storing it on the primary side winding ^^, and transferring the energy stored by the primary side winding Np to the secondary side winding Ns. The output voltage ν 〇υ τ is generated. The switch transistor 406 is coupled to the primary side winding Νρ for controlling energy storage and transfer on the transformer 404 according to a pulse signal VpwM. The switching transistor 406 controls the detailed operation of the transformer 404 to convert energy. Please refer to the prior art described above, which is not described herein. The feedback control device 408 is coupled to the switching transistor 4〇6, and includes a voltage dividing unit 410, a V〇丨tage Follower 412, a comparator (C〇mparat〇r) 414, and a sampling. A Sample-and-Hold unit 416, an error amplifier 418, a control unit, and a reference voltage generator 422 are provided. The feedback control device 408 generates 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 406. The feedback control device 408 will be described in detail as follows. In general, the voltage of the auxiliary winding NA is high voltage for its subsequent stage circuit, so the voltage dividing unit is used to divide the auxiliary winding na. When the lion resistance Na changes, the voltage Vf outputted by the voltage dividing unit 410 also changes accordingly. The voltage follower 412 is coupled to the voltage dividing unit 410 for outputting the voltage signal to the sample and hold unit 416 according to the voltage Vp output from the voltage dividing unit 41. As can be seen from the above, the voltage signal actually reacts to the voltage change of the auxiliary winding > The comparator 414 is coupled to the voltage dividing unit 41A for instantaneously comparing the voltage Vf outputted by the voltage dividing unit 410 with a reference voltage Vref to generate a comparison result, and outputting the first result according to the comparison result. The control signal G1 and a second control signal G2. The sample-and-hold unit 416 is coupled to the voltage follower 4i2 and the comparator 414 for generating a feedback signal according to the voltage signal output by the voltage follower 412, the first control signal G1, and the second control signal G2. At the same time, the U feedback signal is fed back to the reference voltage generator 422. The error amplifier 418_ is connected between the sample-and-hold unit and the control unit 42A, and is used for error-amplifying the feedback signal outputted by the sample-and-hold unit and outputting to the control unit 42A. The control unit 42 is secreted between the error amplifier 4 and the switching transistor 406 for generating a pulse-reduction vPWM' according to the back-sending 1380151 to control the switching transistor 4〇6 to be turned on and off. The reference voltage generator 422 is coupled to the control unit 42A, the comparator 414, and the sample and hold unit 416' for generating a reference voltage Vref used by the comparator 414 according to the feedback signal. As can be seen from the above, the reference voltage Vref is not a fixed voltage but is generated based on the feedback signal. In this way, when the voltage is oscillated in the electrical conversion, the embodiment of the present invention is flexible and fine-tuned, and the voltage of the control doctor is small to avoid sampling and maintaining the voltage of the feedback signal generated by the single το 416. The impact of the shock continues to decrease. Further, the present invention proposes two embodiments, one is that the reference voltage (four) is equal to the multiple of the feedback power (10)-H]; the other is that the reference voltage is equal to the voltage level of the feedback signal - Variable multiple. In other words, if the voltage level of the feedback signal is represented by Ve, the reference Vref shot corresponds to the fine %, wherein the coefficient α can be a constant or a variable. The application of α as a variable will be described later.
先回到回授控制裝置408的運作說明。當輔助繞阻Να上的電 壓準位制_特定輕時，分壓單元·崎_縣^相應地 達到參考紐Vref。此時，賴_“12將電壓％傳遞至取樣 保持^ 416，且比較器414輸出第一控制訊號ω及第二控制訊 Π至取樣保持單元416 ^取樣保持單元416根據第一控制訊號 CH及第二控制訊號G2，對電壓％進行取樣，以產心_號。 換言之，回授控制裝置係根據輔助繞阻^的電壓產生回授 «。同時’回授訊號回授至參考賴產生器422，參考產生 1380151 器422將回授訊號的電壓乘以係數α，以產生參考電壓…技。因此， 參考電壓Vref係動態地隨著回授訊號的電壓準位而改變。接下 來，誤差放大器418將取樣保持單元416所輸出的回授訊號的誤 差放大。最後，控制單元420根據回授訊號產生脈波訊號VpwM， • 以控制開關電晶體406導通及關閉狀態。 此外’第4圖中之分壓單元410包含有電阻R1、幻、_二極 體D1及一電容C3。電阻R1及R2對輔助繞阻Na的電壓進行分 墨，產生電壓VF。電阻R1的一端輕接於輔助繞阻，另一端輕 接於電壓隨耦器412及比較器414。電阻犯的一端耦接於電阻 R1、電壓隨耦器312及比較器414，另一端耦接於一地端。二極 體D1及電谷C3用來穩疋電路。一極體di的負極麵接於電阻Ri、 電阻R2、電壓隨耦器412及比較器414，正極耦接於地端。電容 C3的一端耦接於電阻R1、電阻幻、電壓隨耦器412及比較器414, 另一端耦接於地端。在此請注意，第4圖中之分壓單元41〇僅為 #本發明之-實施例，分壓單元亦可用不同的元件組合實現。 本發明的主要目的在於根翻魏随a的電壓產生回授訊號，因 此可視需要決定分壓單元410的存在與否及其内含元件，不影響 本發明所保護的範圍。 進一步說明取樣保持單元416的運作。取樣保持單元416由至 少開關與至少-電容組成。請參考第5圖，第5圖亦為電源轉 換益40之不意圖’與第4圖不同的是，第5圖之取樣保持單元仙 16 1380151 進一步包含有開關SW卜SW2、電容Cl及C2。開關SW1福接於 電壓隨耦器412及比較器414。開關SW2耦接於比較器414、開 關SW1及誤差放大器418。電容C1的一端耦接於開關SW1及SW2 之間，另一端耦接於一地端。電容C2的一端耦接於開關SW2及 • 誤差放大器418之間，另一端柄接於地端。當電源轉換器的二 •次側繞阻NS上有電流流動時’辅助繞阻Na感應到輸出電壓ν〇υτ 之值，且分壓單元410對輔助繞阻ΝΑ的電壓進行分壓，產生電壓 VF。電壓隨耦器412即時地將電壓Vf輸出至取樣保持單元416。 •同時，當比較器414所產生的比較結果顯示電壓Vf大於參考電壓Returning to the operational description of feedback control device 408. When the voltage level on the auxiliary winding Να is _specifically light, the voltage dividing unit·Saki_County^ correspondingly reaches the reference ref. At this time, the __12 transmits the voltage % to the sample hold 416, and the comparator 414 outputs the first control signal ω and the second control signal to the sample hold unit 416. The sample hold unit 416 is based on the first control signal CH and The second control signal G2 samples the voltage % to generate the heart_number. In other words, the feedback control device generates a feedback « according to the voltage of the auxiliary winding ^. At the same time, the feedback signal is fed back to the reference generator 422. The reference generation 1380151 422 multiplies the voltage of the feedback signal by the coefficient α to generate a reference voltage. Therefore, the reference voltage Vref dynamically changes with the voltage level of the feedback signal. Next, the error amplifier 418 The error of the feedback signal outputted by the sample hold unit 416 is amplified. Finally, the control unit 420 generates the pulse signal VpwM according to the feedback signal, to control the on/off state of the switch transistor 406. The pressing unit 410 includes a resistor R1, a phantom, a diode D1 and a capacitor C3. The resistors R1 and R2 divide the voltage of the auxiliary winding Na to generate a voltage VF. One end of the resistor R1 is lightly assisted. The other end is connected to the resistor R1, the voltage follower 312 and the comparator 414, and the other end is coupled to a ground. The diode D1 is connected to the resistor 412 and the comparator 414. And the electric valley C3 is used to stabilize the circuit. The negative electrode surface of the pole body di is connected to the resistor Ri, the resistor R2, the voltage follower 412 and the comparator 414, and the anode is coupled to the ground. One end of the capacitor C3 is coupled to the resistor. R1, resistor phantom, voltage follower 412 and comparator 414, the other end is coupled to the ground end. Please note that the voltage dividing unit 41 in FIG. 4 is only the embodiment of the present invention, the voltage divider The unit can also be implemented by a combination of different components. The main purpose of the present invention is to generate a feedback signal with the voltage of a, so that the presence or absence of the voltage dividing unit 410 and its embedded components can be determined as needed, without affecting the present invention. The scope of protection. Further describes the operation of the sample-and-hold unit 416. The sample-and-hold unit 416 is composed of at least a switch and at least a capacitor. Please refer to Figure 5, and Figure 5 is also a schematic diagram of the power conversion benefit 40. The sample holding unit of Figure 5 is 16 1638015 1 further includes a switch SW SW2, a capacitor C1 and a C2. The switch SW1 is connected to the voltage follower 412 and the comparator 414. The switch SW2 is coupled to the comparator 414, the switch SW1 and the error amplifier 418. One end of the capacitor C1 is coupled. The switch is connected between the switches SW1 and SW2, and the other end is coupled to a ground end. One end of the capacitor C2 is coupled between the switch SW2 and the error amplifier 418, and the other end is connected to the ground. When the current flows in the secondary winding NS, the auxiliary winding Na induces a value of the output voltage ν 〇υ τ, and the voltage dividing unit 410 divides the voltage of the auxiliary winding , to generate a voltage VF. The voltage follower 412 instantaneously outputs the voltage Vf to the sample hold unit 416. • At the same time, when the comparison result generated by the comparator 414 shows that the voltage Vf is greater than the reference voltage
Vref時，比較器414將輸出第一控制訊號gi以控制開關swi導 通，且輸出第二控制訊號G2以控制開關SW2關閉，進而將電壓 VF即時地記錄於電容C1。另-方面’當比較器414所產生的比較 結果顯示電壓VF小於或等於參考電壓vref時，比較器414將輸出 第一控制訊號G1啸制開關SW1關閉，且輸出第二控制訊號 以控制開關SW2導通，以將電容C1所健存的電量傳遞至電容 # C2。換句話说’電容C2的電壓將跟隨電容C1所記錄的電壓。由 於電容C1即時地記錄電壓Vf，當開關SW1關閉且開關遞導 通時，電容C1所記錄的電壓即為膝點（Knee)電壓值。取樣保持 單元416將此膝點電壓值輸出，因此控制單元·可據以產生回 授訊號。 值件/主思的疋’第4圖及第5圖中之回授控制裝置4〇8為本 發明之實施例，本倾具通常知識者當可據雖適當的變化及修 1 1380151 飾。如前所述，分壓單元410可用不同的元件組合實現。另一方 面，比較器414實需輸出至少一控制訊號。在本發明之其他實施 例中，比較器414可以僅輸出一控制訊號至取樣保持單元416，取 樣保持單元416透過其内部電路’自行產生所需數量的控制訊號， •如透過一反相器產生另一控制訊號。此外，取樣保持單元416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1^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 丨訊號的裝置’皆應涵蓋在本發明的範圍之内。另一方面，電壓隨 耗器412及誤差放大器418可視需要決定其存在與否。請參考第& 圖至第8圖’第6圖至第8圖依序為本發明實施例電源轉換器6〇、 70及80之示意圖。電源轉換器60、70及8〇均類似於第4圖之電 源轉換器40，不同的是，電源轉換器6〇不包含電壓隨搞器412 及誤差放大器418，電源轉換器70不包含電壓隨輕器412 ;電源 轉換器80不包含誤差放大器418。電源轉換器60、70及80中其 餘單元及運作皆與電源轉換器40相同，在此不贅述。 ! 關於第5圖之電源轉換器40之相關訊號的時序波形，請同時 參考第5圖及第9圖。第9圖為電源轉換器40之相關訊號的時序 圖。第9圖令的各訊號分別為控制單元42〇所輸出的脈波訊號 vPWM、一次側繞阻Np上的電流ILm、二次側繞阻Ns上的電流is、 輔助繞阻^的電壓vA、輔助繞阻na的電壓經過分壓單元410分 左，後的電壓VF、第一控制訊號G1、第二控制訊號、電隨 耦器412所輪出之電壓訊號的電壓Va、電容C1的電壓％、以及 18 1380151 電容C2的電壓Vc。電壓vc即回授訊號的電壓準位。由第9圖可 知’輔助繞阻NA的電壓VA的膝點電壓為V0UTx(Ns/NA)，分壓單 元410所輸出之電壓Vf的膝點電壓Vknee為 VOUTx(Ns/NA)xR2/(Rl+R2)(如第9圖中箭頭所示），且電容C1記 錄電壓vF ’電容C2記錄電壓Vf的膝點電壓Vknee，以達成對膝點 電壓Vfcnee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。 零由前述可知，參考電壓Vref等於電壓Vc的α倍，QJ可為常數 或變數。值得注意的是，在電源轉換器處於不正常運作狀態或開 機狀態時，Of為變數之實施例對於穩定電壓Vc有明顯的功效。以 負載極輕的情況為例，當電源轉換器4〇進入保護模式，開關電晶 體406關閉’電壓vc下降，由於負載極輕，輸出電壓νουτ下 降緩慢。當電源轉換器40重新啟動且保麵式解除，瞒輸出電 壓V0UT因下降幅度小而接近正常值，電壓^由較低值或甚至 •接近0值往上升，此時QJ須大於卜使參考電壓财在每一個週 期皆大於電壓VC(制=咖〉％)，也使得電壓％逐漸往上升，When Vref, the comparator 414 will output the first control signal gi to control the switch swi to be turned on, and output the second control signal G2 to control the switch SW2 to be turned off, thereby recording the voltage VF instantaneously on the capacitor C1. In another aspect, when the comparison result generated by the comparator 414 indicates that the voltage VF is less than or equal to the reference voltage vref, the comparator 414 turns off the output of the first control signal G1, the switch SW1 is turned off, and outputs the second control signal to control the switch SW2. Turn on to transfer the amount of energy stored by capacitor C1 to capacitor # C2. In other words, the voltage of capacitor C2 will follow the voltage recorded by capacitor C1. Since the capacitor C1 instantaneously records the voltage Vf, when the switch SW1 is turned off and the switch is turned on, the voltage recorded by the capacitor C1 is the Knee voltage value. The sample hold unit 416 outputs the knee voltage value, so that the control unit can generate a feedback signal. The feedback/controlling device 4〇8 in the fourth and fifth figures of the present invention is an embodiment of the present invention, and the general knowledge of the present invention can be modified according to the appropriate changes and repairs 1 1380151. As previously mentioned, the voltage dividing unit 410 can be implemented with different combinations of components. On the other hand, the comparator 414 actually needs to output at least one control signal. In other embodiments of the present invention, the comparator 414 can output only a control signal to the sample and hold unit 416. The sample and hold unit 416 generates a desired number of control signals through its internal circuit. Another control signal. In addition, the switches and capacitors included in the sample and hold unit 416 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 consumer 412 and error amplifier 418 can determine their presence or absence as needed. Please refer to the & figure to FIG. 8 'Fig. 6 to FIG. 8 for a schematic diagram of the power converters 6 〇, 70 and 80 according to the embodiment of the present invention. The power converters 60, 70 and 8 are similar to the power converter 40 of FIG. 4, except that the power converter 6A does not include the voltage follower 412 and the error amplifier 418, and the power converter 70 does not include voltage Lighter 412; power converter 80 does not include error amplifier 418. The remaining units and operations of the power converters 60, 70, and 80 are the same as those of the power converter 40, and are not described herein. For the timing waveform of the related signal of the power converter 40 of Fig. 5, please refer to Fig. 5 and Fig. 9 at the same time. Figure 9 is a timing diagram of the associated signals of the power converter 40. The signals of the ninth figure are respectively the pulse signal vPWM outputted by the control unit 42〇, 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 resistance, The voltage of the auxiliary winding na is divided by the voltage dividing unit 410, the voltage VF, the first control signal G1, the second control signal, the voltage Va of the voltage signal rotated by the electrical follower 412, and the voltage % of the capacitor C1. And 18 1380151 capacitor C2 voltage Vc. The voltage vc is the voltage level of the feedback signal. It can be seen from Fig. 9 that the knee voltage of the voltage VA of the auxiliary winding NA is VOUTX (Ns/NA), and the knee voltage Vknee of the voltage Vf output from the voltage dividing unit 410 is VOUTx(Ns/NA)xR2/(Rl +R2) (as indicated by the arrow in Fig. 9), and the capacitor C1 records the voltage vF 'capacitance C2 to record the knee voltage Vknee of the voltage Vf for the purpose of sampling and holding the knee voltage Vfcnee. The operation of each signal can be referred to the above, and will not be described here. Zero is known from the foregoing, the reference voltage Vref is equal to α times the voltage Vc, and QJ can be a constant or a variable. It is worth noting that the embodiment where Of is a variable has a significant effect on the stable voltage Vc when the power converter is in an abnormal state or in an on state. Taking the case of extremely light load as an example, when the power converter 4〇 enters the protection mode, the switching transistor 406 is turned off, and the voltage vc drops. Since the load is extremely light, the output voltage νουτ drops slowly. When the power converter 40 is restarted and the surface protection is released, the output voltage VOUT is close to the normal value due to the small drop amplitude, and the voltage ^ is increased from a lower value or even a value close to 0, and the QJ must be greater than the reference voltage. The money is greater than the voltage VC (system = coffee >%) in each cycle, which also makes the voltage % gradually rise.
不受LC共振影響而趨近於〇 ’致使電壓％鎖死在〇值，導致錯 誤操作。 S 請參考第10圖，第10圖為第5圖之電源轉換器4〇處於不正 常運作狀態下，電壓VF、參考電壓Vref及電壓％之關係的波形 圖，且α為變數。如第10圖所示，為變數時，以改變的時間 1380151 點係根據電壓Vc與電壓VF之膝點電壓Vk^比較的結果而決定。 當電壓Vc小於膝點電壓Vknee或電壓VF位於震盪範圍時，本發明 實施例控制〇；>1，以避免錯誤判斷，且使電壓Vc加速接近膝點 電壓Vk„ee。接下來’當電壓Vc大於或等於膝點電壓乂^^時，本 - 發明實施例控制1，以控制電壓Vc趨近膝點電壓。 簡言之’若α為變數且根據電壓Vc與電壓Vf之膝點電壓Vknee 比較的結果而決定，參考電壓Vref即可幫助電壓Vc脫離到電壓 ® VF震盪的影響，同時可幫助電壓Vc穩定地接近膝點電壓Vknee。 此外’請參考第11圖，第11圖為第5圖之電源轉換器4〇開機時， 電壓VF、參考電壓Vref及電壓VC2關係的波形圖。因此，不論 電源轉換器40在不正常運作狀態或是剛開機時，οι為變數之參考 電壓Vref皆可幫助電壓Vc脫離電壓％震盪的影響。 除此之外’請參考第12圖，第12圖本發明之實施例一流程12〇 • 之示意圖。流程120為第4圖中電源轉換器40之操作流程，其包 含下列步驟： 步驟1200 :開始。 步驟1202 :分壓單元410將電源轉換器40之-次側之輔助繞 阻的電壓進行分壓，以產生一分壓訊號。 步驟1204 :電壓隨輕器412根據分壓訊號，輸出電壓訊號。 步驟12〇6 .參考電墨產生器422根據回授訊號，產生參考電壓 Vref 〇 20 1380151 步驟1208 :比較器414將分壓訊號的電壓與參考電壓％奸進 行比較，以產生一比較結果。 步驟1210.比較器414根據比較結果，產生第一控制訊號⑴ 及第一控制訊號G2。 步驟⑵2 :取樣持單元仙根據電壓訊號、第一控制訊號⑺ 及第二控制訊號G2，產生回授訊號。 步驟1214 :誤差放大^| 418將回授峨的誤差放大。 籲 倾1216:控制單元420根據回授訊號，產生脈波訊號VpwM， 以控制電源轉換器40之開關電晶體406的導通及 關閉狀態。 步驟1218 :結束。 關於流程120的詳細運作，請參考前述之電源轉換器4〇，在此 不贅述。值得注意的是，流程120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40不包含電壓隨耦器412，則步驟1204可省略；若電源轉 換器40不包含誤差放大器418，則步驟1212可省略。除此之外， 第5圖之取樣保持單元416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12〇的應用不受限於取樣持 單元416所包含之元件。另一方面，由於比較器414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414可以根據 比較結果’僅產生一控制訊號。取樣保持單元416透過其内部電 路’自行產生所需數量的控制訊號。此外，參考電壓產生器422Being close to 〇 ' without being affected by LC resonance causes the voltage % to lock up at a threshold, resulting in an erroneous operation. S Refer to Figure 10. Figure 10 is a waveform diagram of the relationship between voltage VF, reference voltage Vref, and voltage % when the power converter 4〇 of Figure 5 is in an abnormal operating state, and α is a variable. As shown in Fig. 10, in the case of a variable, the time of change 1380151 is determined based on the result of comparison of the voltage Vc with the knee voltage Vk^ of the voltage VF. When the voltage Vc is less than the knee voltage Vknee or the voltage VF is in the oscillation range, the embodiment of the present invention controls 〇; >1 to avoid erroneous determination, and accelerates the voltage Vc to approach the knee voltage Vk „ee. Next 'when the voltage When Vc is greater than or equal to the knee voltage 乂^^, the present invention controls 1 to control the voltage Vc to approach the knee voltage. Briefly, 'if α is a variable and the knee voltage Vknee according to the voltage Vc and the voltage Vf The result of the comparison determines that the reference voltage Vref can help the voltage Vc to escape the influence of the voltage VV oscillation, and at the same time help the voltage Vc to stably approach the knee voltage Vknee. In addition, please refer to Fig. 11, and Fig. 11 is the fifth. The waveform diagram of the relationship between the voltage VF, the reference voltage Vref and the voltage VC2 when the power converter 4 is turned on. Therefore, regardless of the abnormal operation of the power converter 40 or just after the power-on, the reference voltage Vref of the variable is It can help the voltage Vc to escape the influence of voltage % oscillation. Otherwise, please refer to Fig. 12, Fig. 12 is a schematic diagram of a flow chart 12 of the embodiment of the present invention. The flow 120 is the power converter 40 of Fig. 4. Fuck The process includes the following steps: Step 1200: Start. Step 1202: The voltage dividing unit 410 divides the voltage of the auxiliary winding of the secondary side of the power converter 40 to generate a voltage dividing signal. Step 1204: Voltage accompanying The lighter 412 outputs a voltage signal according to the voltage dividing signal. Step 12〇6. The reference ink generator 422 generates a reference voltage Vref according to the feedback signal. 120 1380151 Step 1208: The comparator 414 divides the voltage of the voltage dividing signal and the reference voltage. The comparison is performed to generate a comparison result. Step 1210. The comparator 414 generates the first control signal (1) and the first control signal G2 according to the comparison result. Step (2) 2: the sampling unit is based on the voltage signal and the first control signal (7) And the second control signal G2, the feedback signal is generated. Step 1214: The error amplification ^| 418 amplifies the error of the feedback 。. The tilting 1216: the control unit 420 generates the pulse signal VpwM according to the feedback signal to control the power conversion The switch transistor 406 of the device 40 is turned on and off. Step 1218: End. For detailed operation of the process 120, please refer to the aforementioned power converter 4〇, here It is to be noted that the process 120 is an embodiment of the present invention, and those skilled in the art can make various changes and modifications according to the knowledge. For example, if the power supply converter 40 does not include voltage-corresponding If the power converter 40 does not include the error amplifier 418, the step 1212 may be omitted. In addition, the sample and hold unit 416 of FIG. 5 includes the switch SW and the SW2 'capacitors C1 and C2. 'It is only one embodiment of the present invention, and the application of the flow 12〇 is not limited to the components included in the sample holding unit 416. On the other hand, since the comparator 414 is required to generate at least one control signal 'in other embodiments of the present invention, the comparator 414 can generate only one control signal based on the comparison result'. The sample and hold unit 416 generates its own required number of control signals through its internal circuitry. In addition, the reference voltage generator 422
21 1380151 所產生的參考電壓Vref等於回授訊號之電壓準位的以倍，α可為 常數或變數。根據流程12G，不論電源轉㈣4G在不正常運作狀 態或是剛開機時，α為變數之參考電壓Vref皆可幫助電壓Vc脫離 電壓vF震盪的影響。 綜上所述，本發明實施例之回授控制裝置係位於電源轉換器之 人側透過比較器及取樣保持單元，記錄輔助繞阻之膝點電壓 作為回授訊號’並且動態地㈣^授訊號的輕雜，產生比較 益所使用的參考龍。因此’本發明實補碰不_用光编合 态及TL431即可實現回授控制，並且可於電源轉換器處於不正常 運作狀態或是開機狀態時，穩定回授訊號的電壓，進而提升電源 轉換器之回授控制功能的效率。 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 圍所做之均等變化與修娜，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圖為本案發明人已提出之—電源轉換器之示意圖。 第4圖至第8圖為本發明實施例電源轉換器之示意圖。 第9圖為第5圖之電源轉換器的相關訊號之時序圖。 第10圖及第11圖為第5圖之電源轉換器之輔助繞阻之分壓、參 考電壓及回授訊號之電壓的波形圖。 22 1380151 第12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、40、50、60， >70、80 電源轉換器 100、200、304、404 變壓器 102、202、306、406 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、400 輸入端 302'402 輸出端 308、408 回授控制裝置 310、420 控制單元 312、414 比較器 314、416 取樣保持單元 410 分壓單元 412 電壓隨耦器 418 誤差放大器 422 參考電壓產生器 NP 一次側繞阻 Ns 二次側繞阻 Na 辅助繞阻 Vin 輸入電壓 23 1380151 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 Vknee 膝點電壓 Vref 參考電壓 120 流程 1200、1202、1204、1206、1208、1210、1212、1214、1216、1218 步驟21 1380151 The generated reference voltage Vref is equal to the voltage level of the feedback signal, and α can be a constant or a variable. According to the process 12G, the reference voltage Vref whose α is a variable can help the voltage Vc to escape the influence of the voltage vF oscillation regardless of whether the power supply (4) 4G is in an abnormal operating state or just after being turned on. In summary, the feedback control device of the embodiment of the present invention is located on the human side of the power converter through the comparator and the sample and hold unit, and records the knee voltage of the auxiliary winding as the feedback signal 'and dynamically (4) The lightness of the miscellaneous, resulting in a comparison of the use of the reference dragon. Therefore, the present invention can realize the feedback control by using the optical editing state and the TL431, and can stabilize the voltage of the feedback signal when the power converter is in an abnormal operating state or the power-on state, thereby improving the power supply. The efficiency of the feedback control function of the converter. The above are only the preferred embodiments of the present invention, and all variations and modifications made in accordance with the scope of the present invention should be within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are schematic views of a conventional power converter. Figure 3 is a schematic diagram of the power converter that has been proposed by the inventor of the present invention. 4 to 8 are schematic views of a power converter according to an embodiment of the present invention. Figure 9 is a timing diagram of the related signals of the power converter of Figure 5. Fig. 10 and Fig. 11 are waveform diagrams showing the voltage division of the auxiliary winding of the power converter of Fig. 5, the reference voltage, and the voltage of the feedback signal. 22 1380151 FIG. 12 is a schematic diagram of a process of an embodiment of the present invention. [Main component symbol description] 10, 20, 30, 40, 50, 60, > 70, 80 Power converter 100, 200, 304, 404 Transformer 102, 202, 306, 406 Switching transistor 104, 204 Pulse width adjustment Variable control unit 106 optical coupler 108 voltage regulation and error amplifying unit 300, 400 input terminal 302'402 output terminal 308, 408 feedback control device 310, 420 control unit 312, 414 comparator 314, 416 sample holding unit 410 partial pressure Unit 412 Voltage Dependent 418 Error Amplifier 422 Reference Voltage Generator NP Primary Side Winding Ns Secondary Side Winding Na Auxiliary Winding Vin Input Voltage 23 1380151 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 Vknee knee voltage Vref reference voltage 120 flow 1200, 1202, 1204, 1206, 1208, 1210, 1212, 1214, 1216, 1218 steps