200807849 九、發明說明: t 明片斤屬 發明領域 本發明主要關於順向電力轉換器,更特別是關於共振 5不連續順向電力轉換器(RDFCs),以及關於用來操作這類轉 換器之改良式系統與方法,以及用來實施這些系統與方法 ^ 之控制器。 【先前技術3 發明背景 10 第1圖(取自美國專利第4688160號)顯示一範例順向電 力轉換器,其包含耦接至一變壓器110之主要繞組1〇9之一 直流輸入101、102。主要繞組109與一開關裝置1〇5串聯連 接,在此之開關裝置係一雙極電晶體,其導通與截止,在 一導通期增進主要繞組109中之磁通量,驅動變壓器之一次 15 級繞組111中的一電。不若一所謂的返馳式轉換器,在一順 向轉換器中主要和次級繞組極性匹配,如第1圖中繞組上之 點所表示者。變壓器110之輸出經一整流器114整流且被一 整平電容器119整平以提供一直流輸出121、122。當開關105 截止時變壓器之核心被「重設」而使得磁通量返回其初始 20 狀態。第1圖之範例中(美國專利第4688160號),此係藉由變 壓器110磁電感與一電容器113分流二極體114之間的共振 動作來實行,將能量傳回輸入電壓源。 第1圖之電路包括在整流器114與整平電容器119之間 的一大的輸出塞117、以及跨接塞子117與整平電容器Π9之 5 200807849 串連組的一自由輪轉或「返馳式」二極體115。這是因為當 開關105截止時,由於主要和次級繞組據有相同的感應,整 流器114馬上變成不導通。自由輪轉二極體115之功能係允 許塞子117在開關1〇5截止時藉由為電流提供一路徑而保持 5 —連續輸出電流進入輸出節點「X」。 第1圖顯示一傳統的連續順向轉換器。有許多前案文件 描述此類轉換器,譬如包括美國專利第4415959號、美國專 利第6760236號、美國專利第6304463號、美國專利第 6252781 號、EP0074399、EP0055064A、以及德儀UCC38C42 10 之參考設計SLUA276。這些前案中後端之電路次級端二極 體被取代以MOS電晶體態樣之同步整流器。其他背景之習 知技述可見於美國專利第4788634號中,其描述一種共振順 向轉換器,其中與變壓器並聯之變壓器自然自感提供一共 振「環」,使得開關電路可自共振;以及美國專利第 15 2005/0270809號(W02004/057745),其說明在一電流限制電 路中使用一輔助變壓器。 發明人確認本發明改良式之操作,諸如改良式的調節 和啟動可藉由利用一不連續電流模式下之開關控制而實 現。 20 【發明内容】 發明概要 依據举發明之第一層面,提供一種用來將一輸入DC電 壓轉換成一輸出DC電壓之不連續共振順向轉換器,該轉換 器包含:第一和第二直流輸入;一變壓器,其具有極性匹 6 200807849 配之主要與次要繞組;一可控制開關,用來切換來自該直 流輸入經過該變壓器之該主要繞組的電力,該可控制開關 與該變壓器之該主要繞組被串聯耦接於該第一與第二直济 電壓輸入之間;第一和第二直流電壓輸出;耦接至該變壓 5器之該次要繞組的一整流器,該整流器與該變壓器之該次 要繞組被串聯耦接於該第一和第二直流電壓輪出之間·,一 整平電容器’其具有被搞接來於一第一連接節點處接收來 自違整流态之直流電的一第一連接節點,該第一連接節點 被粞接至该弟一直流電壓輸出,該整平電容器具有福接至 10該第二直流電壓輸出之一第二連接;以及具有耦接至該可 控制開關且被組配來控制該開關之一輸出的一控制器,使 得該次要繞組上之一電壓波形在該開關導通且電流流入該 第一連接節點之期間具有一第一部份、以及在該開關截止 期間具有一第二實質共振部份;以及其中在該電壓波形之 15該第二部份期間實質上沒有電流流入該第一連接節點。 該整流器與該第一連接節點之間的一連接具有一感應 線圈,且其中實質上在該波形之該第二部份期間沒有電流 流進該感應線圈。然而不需要使用前述所提之大型塞子於 連續順向轉換器中。若具有一電感器,此可具有一小於變 20壓器之1%電感之值,或小於0.1%。順向轉換器之實施例沒 有耦接至次級繞組之一自由輪轉整流器。加上少量的輸出 電感可協助實施電流限制功能(之後將述),供轉換器保持不 連續。 如前所述’依據本發明之一實施例的一順向轉換器, 7 200807849 ”運用開關之$控i刀換而不是仰賴自我振蘯來直接地控制 電源開關。發明人肯認順向轉換器之實施例可容受構件來 數之變異,以特定變壓器之電感與共振電容器之電容,兩 $ 頻率之鞋。發明人肯認在—不連續共振順 ㈣了^ ’反直觀地,可運用-實㈣定頻率振盪器且 =相_構件值„之強健,此接著促進使用具有 二度之構件而因此降低成本。㈣是,大致上說來, :人:繞組上之順向轉換器電星波形之實務上將 個時期,前述中電壓波形之 成― )中的一時期,以及電壓::’其佔據這三個時期 這三個時期中的兩個軸。—貝質共振部份,其佔據 因此藉由控制開關之驅動 長的(在前的)導通期,開闕Μ 』至少將近兩倍 弦共振且波形將近零伏I到超過半周期之正 15 且在實施例中,利用、=(波形在主要端上被鉗制, 扪用之後會說 制,事實上是在二極體降Μ 的又極電晶體開關麵 邻一極俨,ρθ w 離零伏特時被鉗制,因為右 #-極體在開關中)。# U為有―内 時,是再次導通主电壓波形實質上為零伏牲 才疋丹人V通主要端開關 〜伙特 擾(麗)並達到良好的效益。古機’此時可減少電礙干 20 間此電波形保持在實㈣伏、—相對較長的時期,期 選擇以允許某些變異在半週期妓’且㈣振盈器頻率可被 電壓已在實質零伏特時導通二辰之持續時間。當變墨器 變化。因此,較佳地,這類固可顯著的電麼 2.0之-工作週期(導通期 具有小於15: .於 戬止期X另類地,百分比小 8 200807849 10 70%之總時期的-導通期 波形開始正弦 工 作週期)。最後,次級繞組電 期短得足U &再人23響’且21此較㈣卫作週期之截i 工”i避免此波形區域,因此較#地,譬如,《¥ 導通=得__均之比^5:2.G(另類地, ¥通期工作週期大於5%之總時· 另外地或另類地,脈波寬度調變(PWM)和脈波頻率調 變(p輸)之其—或兩者可用來保持料續共振。此促進順向 轉換器之輸ilj調節’特別是在變化的負触件下。然而較 佳地開關控制器係組配來界著運用一對控制信號來控制開 關’一第—控制信號用來令„導通,而—第二控制信號 用來令開義止。此有助於—制不同控制策略之實施, 選擇性地在PWM、及/或舰之背景下。特別是此有助於零 伏特切換(ZVS)之f務’以及-不連續共振順向轉換器背景 下之過電流保護(OCP)。 15 因此在一些較佳實施例中,一第一控制信號控制開關 導通而一第二控制信號控制開關截止。在實施例中,第_ 控制信號可響應於主要繞組電壓上檢测到的一實質零伏特 條件。此可用來另電源開關即刻導通,或經一延遲後導通。 另類地,可運用來自變壓器之一輔助繞組之一電壓。更一 20般的,所感測電壓可相較於以參考位準而不一定是零伏 特。在又另一類電源開關中可響應於流經主要繞組與開關 之一感測電流而導通,譬如藉由測量一電流感測電阻上之 一電壓降來感測。此可被用來,譬如,延遲電源開關之導 通。截止電源開關之第二控制信號,亦可響應於一或更多 9 200807849 不同的變因。譬如在一簡單實施例中,從第一控制信號控 制電源開關導通之一時間延遲後第二控制信號可控制開關 截止。選擇地此時間延遲可變化,且比此方式可實施脈波 寬度調變。脈波寬度可響應於,譬如,在變壓器之主要或 輔助繞組上的一電壓、及/或響應於順向轉換器之次級端上 的一感測電壓。理應瞭解的是,一般而言,變壓器之主要(或 次級)繞組上的電壓可直接或間接地被感測。通常,第二控 制信號可響應於任何主要或次級端電壓或電流。 10 15 在一些特定較佳實施例中,第二控制信號實施一過電 流保護(OCP)功能,藉由在檢測到一過電流條件時實質地即 刻切換電源開關截止,譬如經由一感測器(例如一電流感測 電阻)所感測之電壓。此可用來實施一週期間ocp並有助於 在檢測到一開關電流大於臨界時快速響應。 在-些較佳實施例中,控制器實施一電流限制模式, 其包括增加鮮操作。因此在實_巾,㈣器在電流限 制時增加驅動信號之i率。此有助於避免-控制不住的 處理(稱後將制),其對某種_之負載會造成輸出電壓連 續地下降。在實施财,電流限制之—臨界電流 動信號變化之頻率或脈浊f p A1 .、驅 飞版波見度而調整,且在特定臨界電产200807849 IX. INSTRUCTIONS: t FIELD OF THE INVENTION Field of the Invention The present invention relates generally to forward power converters, and more particularly to resonant 5 discontinuous forward power converters (RDFCs), and to operating such converters Improved systems and methods, and controllers for implementing these systems and methods. [Prior Art 3 Background of the Invention 10 Figure 1 (taken from U.S. Patent No. 4,688,160) shows an exemplary forward power converter comprising one of the primary windings 1 〇 9 of the transformer 110, DC input 101, 102. The main winding 109 is connected in series with a switching device 1〇5, wherein the switching device is a bipolar transistor which is turned on and off, and the magnetic flux in the main winding 109 is increased during an conducting period to drive the primary winding of the transformer. One of the electricity. Rather than a so-called flyback converter, the primary and secondary windings are polarity matched in a forward converter, as indicated by the point on the winding in Figure 1. The output of transformer 110 is rectified by a rectifier 114 and leveled by a leveling capacitor 119 to provide a DC output 121,122. When the switch 105 is turned off, the core of the transformer is "reset" to return the magnetic flux to its initial 20 state. In the example of Fig. 1 (U.S. Patent No. 4,688,160), this is carried out by a resonant action between the magnetic inductance of the transformer 110 and a shunt diode 114 of a capacitor 113, which returns energy to the input voltage source. The circuit of Fig. 1 includes a large output plug 117 between the rectifier 114 and the leveling capacitor 119, and a free-wheeling or "return-type" of the series connection of the plug 117 and the leveling capacitor Π9. Diode 115. This is because when the switch 105 is turned off, since the primary and secondary windings have the same induction, the rectifier 114 immediately becomes non-conductive. The function of the freewheeling diode 115 allows the plug 117 to maintain a continuous output current into the output node "X" by providing a path for the current when the switch 1〇5 is turned off. Figure 1 shows a conventional continuous forward converter. There are a number of prior documents describing such converters, including, for example, U.S. Patent No. 4,415,959, U.S. Patent No. 6,760,236, U.S. Patent No. 6,304,463, U.S. Patent No. 6,252,871, EP 0 074 399, EP 0055064 A, and Deutsche UCC 38 C42 10 Reference Design SLUA 276 . The secondary side diodes of the back end of these prior cases are replaced by synchronous rectifiers in the MOS transistor state. A further background of the prior art can be found in U.S. Patent No. 4,788,634, which describes a resonant forward converter in which a natural self-inductance of a transformer in parallel with a transformer provides a resonant "ring" that allows the switching circuit to self-resonate; Patent No. 15 2005/0270809 (W02004/057745), which describes the use of an auxiliary transformer in a current limiting circuit. The inventors have confirmed that the improved operation of the present invention, such as improved regulation and activation, can be achieved by utilizing switching control in a discontinuous current mode. 20 SUMMARY OF THE INVENTION In accordance with a first aspect of the invention, a discontinuous resonant forward converter for converting an input DC voltage to an output DC voltage is provided, the converter comprising: first and second DC inputs a transformer having a polarity of 6 200807849 with primary and secondary windings; a controllable switch for switching power from the DC input through the primary winding of the transformer, the controllable switch and the primary of the transformer a winding coupled in series between the first and second straight voltage inputs; first and second DC voltage outputs; a rectifier coupled to the secondary winding of the transformer 5, the rectifier and the transformer The secondary winding is coupled in series between the first and second DC voltage turns, and a leveling capacitor 'which has been coupled to receive DC current from the rectified state at a first connection node a first connection node, the first connection node is connected to the brother's DC voltage output, and the leveling capacitor has a second connection to the second DC voltage output And a controller coupled to the controllable switch and configured to control an output of one of the switches such that a voltage waveform on the secondary winding is turned on and current flows into the first connection node Having a first portion and having a second substantial resonant portion during the turn-off of the switch; and wherein substantially no current flows into the first connection node during the second portion of the voltage waveform. A connection between the rectifier and the first connection node has an inductive coil, and wherein no current flows into the inductive coil during substantially the second portion of the waveform. However, it is not necessary to use the aforementioned large plug in the continuous forward converter. If it has an inductor, this can have a value less than 1% of the inductance of the transformer, or less than 0.1%. The embodiment of the forward converter is not coupled to one of the secondary winding freewheeling rectifiers. A small number of output inductors can be used to assist in implementing the current limit function (described later) for the converter to remain discontinuous. As described above, a forward converter according to an embodiment of the present invention, 7 200807849 "uses the control of the switch instead of relying on self-vibration to directly control the power switch. The inventor will recognize the forward conversion The embodiment of the device can accommodate the variation of the number of components, the inductance of the specific transformer and the capacitance of the resonant capacitor, the two-frequency shoes. The inventor will recognize that - discontinuous resonance is smooth (four) ^ 'anti-intuitive, can be applied - Real (iv) constant frequency oscillator and = phase_component value „ robustness, which in turn facilitates the use of components with a second degree and thus reduces costs. (d) Yes, roughly speaking, : Man: The forward converter of the electric star waveform on the winding will be a period of time, the middle voltage waveform is formed into a period of -) and the voltage:: 'It occupies these three Two of the three periods of the period. a shellfish resonance portion that occupies a (previous) conduction period by which the control switch is driven, the opening is at least nearly twice the string resonance and the waveform is approximately zero volts I to more than half the positive period of 15 cycles and In the embodiment, the use, = (the waveform is clamped on the main end, after the use is said, in fact, the diode is lower than the pole of the transistor switch surface, ρθ w from zero volts It is clamped because the right #-pole is in the switch). # U is in the inner, is the main voltage waveform is turned on again, the voltage is essentially zero volts, then the dandan V-pass main end switch ~ gang special disturbance (Li) and achieve good benefits. The ancient machine 'can reduce the electric interference at this time. The electric waveform is kept at the real (four) volts, a relatively long period, the period is selected to allow some variation in the half cycle 且' and (4) the vibrator frequency can be voltage The duration of the second pass is turned on at substantially zero volts. When the ink changer changes. Therefore, preferably, such a solid can be significantly improved by 2.0 - duty cycle (the conduction period has less than 15: in the end period X is alternatively, the percentage is small 8 200807849 10 70% of the total period - the conduction period waveform Start the sine duty cycle). Finally, the secondary winding power period is short enough for U & second person 23 rings 'and 21 this is more than the (four) guard cycle interception i" avoid this waveform area, so compared to #地,如如, "¥通通=得_ _ even ratio ^5:2.G (alternatively, the total period of the working period of the period is more than 5% of the total time · additionally or alternatively, pulse width modulation (PWM) and pulse frequency modulation (p loss) It—or both—can be used to maintain the regenerative resonance. This facilitates the regulation of the forward converter's input ilj', especially under varying negative contacts. However, it is preferred that the switching controllers are configured to use a pair of controls. The signal is used to control the switch 'one--the control signal is used to make „ conduction, and the second control signal is used to stop the escrow. This helps to implement different control strategies, optionally in PWM, and/or In the context of the ship, in particular, this contributes to the zero-volt switching (ZVS) and the overcurrent protection (OCP) in the context of a discontinuous resonant forward converter. 15 Thus in some preferred embodiments, A first control signal controls the switch to be turned on and a second control signal controls the switch to be turned off. In an embodiment, the _th control signal can be Responding to a substantially zero volt condition detected on the primary winding voltage. This can be used to turn the power switch on immediately or after a delay. Alternatively, one of the auxiliary windings from one of the transformers can be used. Generally, the sensed voltage can be compared to a reference level and is not necessarily zero volts. In yet another type of power switch, it can be turned on in response to a current flowing through one of the main windings and the switch, such as by measuring one. A voltage drop across the current sense resistor is sensed. This can be used, for example, to delay the conduction of the power switch. The second control signal to turn off the power switch can also respond to one or more of the different causes of 200807849 For example, in a simple embodiment, the second control signal can control the switch to be turned off after the time delay of the power switch is turned on from the first control signal. Optionally, the time delay can be varied, and the pulse width modulation can be implemented in this manner. The pulse width may be responsive to, for example, a voltage on the primary or auxiliary winding of the transformer, and/or in response to a sense on the secondary side of the forward converter. Voltage. It should be understood that, in general, the voltage on the primary (or secondary) winding of the transformer can be sensed directly or indirectly. Typically, the second control signal can be responsive to any primary or secondary voltage or current. In some specific preferred embodiments, the second control signal implements an overcurrent protection (OCP) function to substantially instantaneously switch the power switch off when an overcurrent condition is detected, such as via a sensor. The voltage sensed (eg, a current sense resistor). This can be used to implement an ocp during a week and to help respond quickly when a switch current is detected that is greater than a critical value. In some preferred embodiments, the controller implements a current The limit mode, which includes adding fresh operation, is therefore used to increase the i-rate of the drive signal when the current is limited. This helps to avoid - uncontrollable processing (called post-production), which causes a constant drop in output voltage for a certain load. In the implementation of the financial, the current limit - the critical current dynamic signal change frequency or pulsation f p A1., the fly-off version of the wave is adjusted, and in a specific critical electricity
下可被隨驅動脈波寬度減少或驅動頻率增加而增加。如前L 所述,順向轉換器之輸出端可包.小«,且容_於 -不連續共振模式下,且包含此 ; 過負載之輸出電流,_是__節) 符別疋猎由促進輸出電流之調節, 前所述。在實施例中,此雷威 此電感可由電路中之洩露或寄生電 20 200807849 在實施例中,變壓 向轉換器貢獻一理 感來提供,特別是變壓器之⑽電感。 器可被組配來提高一洩露電感以針對順 想輸出電感值。 ' 2向電力轉換轉計上經常發生的-種_處再於確 保可罪的啟動。此是因為在啟動時順向轉換器輸出形同一 短路電路,這會潛在地損害一電流限制配置所在之電源開 關或會觸發電流限制,因㈣止輸出電壓達到其適當的 值。我們所述之順向轉換器實施例,運用一種配置以促進 一順向轉換器啟動之管理的-受控方式來令電源開關導通 10和截止,尤其是,致用一驅動信號之一頻率來令開關之電 源增加到啟動。此令轉換器啟動時離開其運作之共振模式 並致使更多電力轉移到輸出同時仍保護電源開關。啟動條 件可直接地在順向轉換器之主要端被檢測,或間接地藉由 使用順向轉換器中之一電流感測/限制系統。 15 在一些特定較佳實施例中,前述控制器係實施以一單 一積體電路。此1C可實施一或更多控制策略,如前所述。 然而在一些1C之較佳實施例中,電源開關為了適應性之考 量而不在晶片上。 因此在牟發明另一層面中提供一種用來控制一順向轉 20 換器之控制器,該順向轉換器用來將一輸入DC電壓轉換成 一輸出DC電壓,該轉換器包含:第一和第二直流輸入;具 有極性匹配之主要和次要繞組的一變壓器;用以切換來自 該直流輸入經過該變壓器之該主要繞組的電力的一可控制 開關,該可控制開關與該變壓器之該主要繞組被串聯耗接 11 200807849 於該第一和第二直流電壓輸入之間;第一和第二直流電壓 輸出;耦接至該變壓器之該次要繞組的一整流器,該整流 器與該變壓器之該次要繞組被串聯耦接於該第一和第二直 流電壓輸出之間;以及具有耦接來於一第一連接節點處接 5 收來自該整流器之直流電之一第一連接的一整平電容器, 該第一連接節點被耦接至該第一直流電壓輸出,該整平電 容器具有耦接至該第二直流電壓輸出之一第二連接;以及 其中該控制器具有耦接至該可控制開關且係組配來控制該 開關之一輸出,使得該次要繞組上之一電壓波形在該開關 10 導通以及電流流入該第一連接節點期間具有一第一部份、 以及在該開關截止期間具有一第二實質共振部份;以及其 中在該電壓波形之該第二部份期間實質上沒有電流流入該 第一連接節點;藉此該順向轉換器可被該控制器控制來操 作在一不連續順向電壓轉換模式下。 15 較佳地控制器係如前述實施於一單一積體電路上。 本發明更進一步之層面提供一種控制前述之在一不連 續共振模式下運作之一順向轉換器之方法,藉由控制可控 制(電力)開關使得次級繞組上之一電壓波形具有一第一部 份,其間開關導通且電流流入第一連接節點、以及一第二 20 實質共振部份,其間開關截止且在電壓波形之第二部份其 間實質上沒有電流流入第一連接節點。 依據本發明另一層面,提供一種用於一共振不連續順 向轉換器(RDFC)之一控制器,該順向轉換器包括具有極性 匹配之第一和第二繞組的一變壓器以及用來切換直流電至 12 200807849 該變壓器之該第一繞組的一開關,該轉換器更具有耦接至 忒、交壓器之該第二繞組之一直流輸出,其中該控制琴具有 兩種模式··-第-才喿作模式,其在該開關受控制期間用來 以實質上與操作該RDFC之一共振頻率同步之_頻率來切 5換戎直流電,使得該自該直流輸出供電,以及一第一 (減少電力)操作模式,其間該開關之驅動受控制以增加該開 關被截止期間之時間比例。 在一些較佳實施例中,開關驅動包含一脈波與脈波寬 度(持續的)被減少,在第二降低電力操作模式下。令外或另 1〇類地在降低電力操作模式下,開關之一或更多共振頻率週 期被跳過。在此之後的例子中,當開關接著被導通時,為 進一步增加RDFC導通之效率,計時以實質地與一導通點同 步,更特別地是在RDFC之一共振波形的波谷。 在一些較佳實施例中,控制器係組配來自動感測一降 15低的負載條件,且用來響應於此而選擇一第二降低電力操 作模式。譬如控制器可感測到一降低的負載條件,藉由感 測至控制态之一電源供應,其處控制器係以一積體電路之 型號貫施,至1C之一電壓源。另外或另類地控制器可選擇 降低電力模式藉由感測RDFC之操作時脈,尤其是在電源開 20關截止(一個週期以上之循環)期間檢測一個以上之共振。用 來識別降低負載條件之進一步操作包括在RDFC之一輸出 端上感測(譬如於順向轉換器之輸出端上利用一電流感測 電阻)及藉由變壓器上之一輔助繞組感測。 在一些特定較佳實施例中,控制器係組配來控制開關 13 200807849 之驅動,使得開關僅在開關上之電壓將近〇¥時被導通。(在 實化例中,開關上之電壓事實上可能永遠不會為〇v,因為, 如,可旎因為有一個二極體壓降);此特別地有用。 在一些較佳實施例中,第二降低電力操作模式包含一 5 RDFC待機模式。 依據本發明另一層面,提供一種用於一插電共振不連 續順向轉換器(RDFC)之控制器,該順向轉換器包括具有極 性匹配之第一和第二繞組的一變壓器、以及用來切換至該 k壓為之该第一繞組之直流電的一開關,該轉換器更具有 ίο耦接至該變壓器之該第二繞組的一直流輸出,且其中至該 第一繞組之該直流電係從一總電源供應衍生出,並包含總 漣波之一成份,該控制器包含:用來感測該總漣波之一漣 波感測輸入,以及輕接至該漣波感測輸入且具有用來控制 至该開關之一驅動信號之一輸出的一時脈控制模組,該驅 15動佗號包含具有用來驅動該開關導通之一脈波導通期以及 用來驅動該開關截止之一脈波截止期的一脈波;以及其中 該時脈控制模組係組配來響應於該第二總漣波變化該脈波 之一寬度與一頻率之其中一者或兩者,用以抑制該直流輸 出中該漣波之一成份。 20 漣波感測輸入可在多數點處感測家用或格狀總漣波, 包括,但不限為,RDFC之直流輸出、開關、及來自rdfC 之變壓态上的一輔助繞組。較佳地控制器亦包括一進一步 的感測輸入,用來調節轉換器之直流輸出。較佳地時脈控 制模組輸出包含第一和第二輸出線,用以分別控制開關導 14 200807849 通與截止;控制器較佳地進一步包含一開關控制模組,響 應於這些輸出線來控制開關導通或截止一 off。 在一牟發明相關層面中提供一種用來抑制一插電共振 不連續順向轉換器(RDFC)中之漣波的方法,該順向轉換器 5包括具有極性匹配之第一和第二繞組的一變壓器、以及用 以切換至該變壓器之該第一繞組之直流電的一開關,該轉 換器更具有耦接至該變壓器之該第二繞組之一直流輸出, 該方法包含:感測該RDFC之一信號中之總漣波的一成份; 以及控制至該開關之一驅動信號的一脈寬及一脈波頻率之 10 其中"者或兩者來抑制該連波。 在又另一丰發明層面中提供一種用於一共振不連續順 向轉換器(RDFC)之一控制器,該RDFc包括一變壓器及用 來切換至該變壓器之直流電的_電源開關,其中該控制器 係組配來在該RDFC啟動期間限制該開關中之一電流。 15 在實施例中,開關包含一電晶體,特別是一雙極電晶 體,電流限制可包含操作電晶體於一非線性區。另外或另 類地控制器可被組配來增加一控制信號之一頻率來在啟動 以在此時限制電流期間進行切換。頻率可以一因數,譬如, 2,5,10或以上被增加到一正常操作頻率之上。因此在實 2〇施例中,控制器可組配來控制虹直流使其在啟動時為非共 振的。啟動解可包含-固定頻率或視從卿⑽測到之_ 4吕號而疋之一頻率。 在又另一牟發明層面中,提供56. -種用於一共振不 連續順向轉換器(腳c)之一控制器,該rdfc包括一變壓 15 200807849 器以及用來切換至該變壓器之直流電的一電源開關,其中 該開關係組配來切換至該變壓器之一繞組之電力,其中該 控制器包含用來感測該變壓器之該繞組中之一電壓以及響 應於該感測控制該開關部份導通的一系統。 5 在此實施例中,變壓器包含一輸入繞組與一輸出繞 組,開關係組配來切換至變壓器之輸入繞組之電力。在開 關所連接之輸入繞組上之一節點,一急遽的壓升會發生於 開關截止時(一般響應於變壓器之輸入與輸出繞組端不一 致時),且此電壓過衝可藉由部份地導通開關而受到控制與 10 限制,在感測與補捉過衝之功效上。 因此在又另一丰發明層面提供一種控制一共振不連續 順向轉換器(RDFC)之方法,該RDFC包括一變壓器與一電 源開關來切換至該變壓器之直流電,此方法包含感測該變 壓器之該繞組上之一電壓及控制該開關響應於該感測而部 15 份地導通來限制電壓過衝之步驟。 在牟發明又另一層面中提供一種在一共振不連續順向 轉換器中之電流限制方法,該順向轉換器包括具有極性匹 配之第一和第二繞組之一變壓器、以及用來切換至該變壓 器之該第一繞組之直流電的一開關,該轉換器更具有耦接 20 至該變壓器之該第二繞組之一直流輸出,該方法包含檢測 一電流限制條件;以及響應於該檢測增加至該開關之一控 制信號的一頻率。 在举發明一相關層面中提供一種用於一共振不連續順 向轉換器(RDFC)之一控制器,具有極性匹配之第一和第二 16 200807849 繞組之一變壓器、以及用來切換至該變壓器之該第一繞組 之直流電的一開關,該轉換器更具有耦接至該變壓器之該 第二繞組之一直流輸出,該控制器包含:用於檢測一電流 限制條件之裝置;以及響應於該檢測增加至該開關之一控 5 制信號的一頻率的裝置。 本發明又進一步提供一種用於一共振不連續順向轉換 器(RDFC)之一控制器,該控制器具有用來感測來自該共振 不連續順向轉換器之一或更多信號的一或更多輸入,該控 制器其更包含用來分析該一或更多所感測信號之一系統, 10 用以為該RDFC之一電源開關判定導通與截止時間;以及一 輸出,用以依據該判定的導通與截止時間提供一驅動信號 給該開關。 在又另一相關牟發明層面中提供一種控制一共振不連 續順向轉換器之方法,該順向轉換器包括具有極性匹配之 15 第一和第二繞組的一變壓器、以及用來切換至該變壓器之 該第一繞組之直流電的一開關,該轉換器更具有耦接至該 變壓器之該第二繞組的一直流輸出,該方法包含利用具有 一或更多輸入之一控制器來感測來自該共振不連續順向轉 換器之一或更多信號,並分析該一或更多所感測信號來判 20 定該開關之導通和截止時間,以及依據該判定的導通與截 止時間提供一驅動信號給該開關。 在又另一举發明層面中提供一種操作一共振不連續順 向轉換器之方法,使得該共振不連續順向轉換器具有較低 的靈敏度並容忍該共振不連續順向轉換器之一或更多共振 17 200807849 該方法包含湘—自發錄器驅_共振不連續順 向轉換器之-電源開關,該振盪器之一實質固定頻率盥一 其中一者或兩者被選定,當該開關上實質i為 令伏特時使得該開關被導通。 10 15 20 “此方式在此只^例中,RDFC被組配來操作於一實 貝尽電壓切換模式下,針對—範圍之不同(共振)構件值。此 促使降低-現實具有低構件數且因此潛在地為 咖〇電縣減《業實務,㈣在此實㈣a , 節(主要)磁電感與共振電容器中之變異確保高效率之^凋 因此在一相關層面中又進一步提供70.-種用來呆作。 -共振不連續順向轉換器之控制器,使得該共振趣制 向轉換H具有較低的靈敏度並容料共振不連續 ^ 裔之-或更多共振構件,該控制器包含用來驅動該專攝 連續順向轉換器之-電源開關的—自發振盪器; 該振盡器之-實質固^頻率和—工作週期之苴中、中 =選定’ W關上實質上為 在又另-树明層面巾提供72·—則於— _順向轉換器之控制器,該川員向轉換器包括具有極性^ 之第-和第二繞組的—變壓器、以及用來切換至該變^ 之該第-繞組之直流電的—開關’該轉換器更具=11 該變壓器之該第二繞_—直流輸出,該控制器^ 控制該順向轉換器操作於一受控振逢模式下,盆中,配來 器具有-操作週期,其中包括電流流入該變壓器之:轉換 18 200807849 和第二繞組的一第一(導通)部份、以及一實質共振電壓波形 出現在該變壓器之該第一繞組與該開關間之一連接的一第 二(截止)部份,且其中該控制器具有用以感測來自該共振不 連續順向轉換器之一信號的至少一感測信號輸入、以及用 5 來響應於該所感測信號控制該開關操作該順向轉換器於該 受控振盪模式下之一輸出。 較佳實施例中所感測信號響應於該變壓器中之一能量 位準。較佳地控制器之實施係利用具有第一與第二開關控 制輸入之一開關控制模組來接收個別之導通與截止控制信 10 號。較佳地這些係由一比較器來驅動,該比較器比較所感 測信號與一參考;較佳地另一者亦由比較器輸出驅動,但 經延遲,特別是藉由一可變脈波寬度計時器。以此方式開 關可被控制導通,當在該開關上感測到之一電壓達到參考 電壓時,並在一預定或可變時間後被控制截止。在一些較 15 佳實施例中,截止控制信號亦以一過電流保護信號閘控使 得在檢測到一過電流條件時,開關可被控制馬上截止。在 其他配置中,開關之導通與截止可被分別控制;另類地, 開關之導通與截止各自可藉RDFC輸入端上感測之一電壓 及/或電流來控制。 20 在實施例中開關於一時間被導通(其可為一固定的時 期,或可為零)在電壓實質’上達零時、及/或響應於感測經 過變壓器之第一(輸入)繞組一電流的一電流感測信號(電 壓)。在實施例中,開關在一固定或可變導通時間之後截 止、及/或響應於在RDFC輸入端之所感測之一電壓及/或電 19 200807849 /瓜在貝施例中,控制器可響應於一個以上感測自RDFC之 信號。在實施例中,RDFC缺乏與輸出端整流器並聯之一電 谷器’反而RDFC係組配來達到共振而不需任何與整流器相 關聯之内部寄生電容之外的電容。 5 RDFC可併用於一總電源開關。這樣的實施例中,一高 κ電C可直接自柵狀總電源衍生,譬如藉由一橋接整流 器,此提供-輸入至RDFC,其係組配來產生一更低的直流 輸出電壓,譬如小於50V,4〇v,3〇v,2〇v或·。 在一些較佳實施例中,前述本發明控制器係實施於一 10單晶片積體電路中,選擇性地包括電源開關。 前述之一控制器可實施以類比或數位電路。因此,當 控制器主要或全部地以數為電路實施時,牟發明更提供一 種載體,用來載荷處理器控制碼,例如眺(暫存器轉移層) 或界定硬體之系統C來實施控制器。 15 依據本發明之又另一層面提供有-順向電力轉換器, 此電力轉換器包含:-輸入;具有一主要與一次要繞組之 -變壓器;組配來彻換來自該輪入之電力穿過該主要繞組 之一電源開關;耗接至該次要繞組之一輸出;以及一控制 系統,該控制系統具有-感測輪入,且被組配來控制該開 關之-切換時脈以響應於來自該感測輸入之一感測信號調 節來自該順向轉換器之電力輪出;以及其中該感測輸入被 連接來接收來自該順向轉換器之—主要端的該感測信號。 提供一輸人至控❹統之感測信號可包含-電壓及/ 或-電流感測信號。控制系統可調節順向電力轉換器之一 20 200807849 輸出電壓及/或一輸出電流。 本發明亦提供_種針對一主要端感測 之控制器,特別如前所述。 寻谀~ =於此技藝者可瞭解到前述之_不連續共振順 :::用::路拓樸範圍來實施,其中包括但不限為之後 所述者。譬如’變壓器可包含 圖式簡單說明 … 例之現ΓΓ:!Γ本發明之這些與其他層面,藉由範 ^方式,並參考所附圖式,其中·· 10 第1圖顯示習知之一順向轉換器範例。 第冰_分別顯示一不連續共振顺向轉換器之實施 卜:乂及第2a圖之轉換器之一範例時脈與控制配置; 第3a和3b圖顯示第2a圖之順向轉換器自_i7〇v直流輪 15 波形; 入供應提供分別為1 A和2 A之輸出電流操__之範例 说Μ · 第4圖顯不依據本發明之一實施例之一順向轉換器電 源供應之一等效電路模型; 。第5a_5d圖顯示依據本發明之—實施例之一順向轉換 器之另類拓樸; 第6a-6c圖顯示依據本發明之一實施例之利用一輔助 繞組來重設一順向轉換器之一變壓器之例子。 第7a和7b圖分別顯示一順向轉換器在啟動期間不具有 和具有高頻控制之波形; 第8a-8c圖分別顯示依據牟發明之一不連續共振順向 21 200807849 轉換器實施例的輸入感測連接組態以及在過負載與無負載 條件下之一順向轉換器; 第9a-9c圖分別顯示一順向轉換器之遲、早、及目標波 形時脈的範例; 5 第1 〇 a和10 b圖分別顯示利用次級端回授之一順向轉換 器與一多相順向轉換器電路之調節; 第11圖顯示共振不連續順向轉換器之波形,其運用脈 波跳過與共振波谷切換例說一開關驅動脈波、一開關(集極) 電流、及一開關(集極)電壓之範例波形;而 10 第12圖顯示示範性的一共振不連續順向轉換器之電壓 感測電路技術,特別是漣波減少。 L實施方式:J 較佳實施例之詳細說明 本說明書中,我們說明控制共振不連續順向轉換器。 15 在一範例RDFC中,至一變壓器之一主要或輸入繞組之電力 被切換,而與主要繞組極性匹配之變壓器之一次級或輸出 繞組被耦接至一整流器,其提供直流電至一整平電容器, 直流電自此連接節點被供至RDFC輸出。變壓器之次級繞組 上的一電壓波形具一第一部份,其間開關導通而電流流入 2〇 連接節點,以及第二實質共振部份,期間開關與整流器都 被截止。實質上在第二部份之電壓波形期間沒有電流流入 連接節點(除了來自整平電容器)。 在設計上,我們描述一種在整流器與連接節點之間的 連接,其可包括一小的電感器(譬如小於5%主要端磁電 22 200807849 感)’但實I上在波形之第二共振部份期間沒有電流流入此 電感中且不需要用在—連續順向轉換器中的那種大塞子。 不需連接-電容器跨過整流器來達到共振;在實施例中, 我們共振實質上只跨過開關,而不括跨過次級二極體。更 5 2職是在實施例中,我們使用在主要端上具有—附加電 谷器之變壓器之磁電感來在截止週期達到乓振。 在一些較佳實務中,RDFC針對交流—直流轉換而組 配,並因此包括一交流-直流轉換器,例如在主要端上之一 橋接式整流器。在某些特定較佳實務中,RDFC^^、插電式 10的,且主要端係由一咼直流電壓(譬如大於7(Wdc、l〇〇Vdc、 150V直流、或200Vdc)所供電,同時次級端直流電壓很低(譬 如,小於20V直流或lOVdc)。在實施例中,我們於主要端上 運用零電壓切換(即一主要端開關被在^一開關上之電壓接 近零伏特時被導通),但我們忽略切換時的次級二極體損 15 失。 我們亦將說明用來實施一共振不連續順向轉換器 (RDFC)之技術,其運用一控制系統來以一受控方式令 RDFC之一電源開關導通和截止。如前述,控制系統可操作 於一未受控之固定頻率模式下,或控制系統可感測來自一 20 或更多輸入並響應於此感測決定何時令電源開關導通和截 止,譬如來實施脈波寬度及/或頻率調變。此有助於RDFC 之調節,其細節上係可利用一演算法來實行。一種系統, 使用控制系統來操作RDFC補償電路變數及在一零電壓切 換(ZVS)模式下運作。轉換器亦可控制啟動及/或電流限制 23 200807849 期間之切換頻率來保護電源開關及增加轉移至負載之能 量。控制系統較佳地利用一控制1(:(積體電路)實施。 如前所述,腳c之操作不需一自由輪轉或返驰式二極 n,且具有或不具有一輸出電感器。然而,若此輸出電感 5器小得足以確保順向轉換器在一不連續模式下操作,且實 質上在或接近共振。 現在參考第2a圖,此顯示依據牟發明之不連續共振順 向轉換器2()()之-實施例。第2b圖顯示用於第以圖之順向轉 換器之一範例時脈和控制系統21〇。 10 I考第2a® ’此顯示—完全共振不連續模式順向轉換 器200 ’其具有耦接至串聯與一電源開關212之一變壓器2〇6 之主要繞組204的一直流輸入202。一共振電容器214被跨接 ^:壓器之主要繞組’而直流輸入2〇2備具一整平電容写 216。順向轉換器之輸出端上,變壓器之一次級繞組2〇8經 15由一整流器220提供電力至一對直流輸出端218。一整平電 容器222跨接直流輸出端218與在整流器220之接面的一輸 出節點,整平電容器222和至其中一直流輸出端218之一連 接被標為「X」。進入節點X之電流,其流入整平電容器222 或正平黾谷器222和輸出218兩者,係不連續的,相對於第1 20 圖所顯示之電路。 開關212可包含一雙極或MOS電晶體,例如一 MOSFET,或IGBT,或一些其他裝置。整流器22〇可實施為 一個二極體或藉由一MOS電晶體。共振電容器214可包含一 離散構件,或可完全由寄生電容提供,或可包含兩者之一 24 200807849 組合。 開關212被一控制器210所控制,開控制器21〇包含一時 脈控制模組210a及一開關控制模組210b,時脈控制模組提 供開關導通與開關截止信號210c至開關控制模組21〇b。時 5脈控制模組可具有一或更多感測輸入,例如一電壓感測輸 入以及所繪示之一電流感測輸入,或這樣的感測動作可被 省略,而時脈控制模組210a實質上可獨力於任何順向轉換 器電路之感測條件地操作。 在運用電壓感測之處,變壓器之主要繞組上的電壓可 10被感測,或直接或間接地。譬如電壓可如圖所示藉由至主 要繞組與開關間之一接面的一連接被感測;另類地,譬如, 一感測電壓可來自於變壓器之一輔助繞組(未顯示於第2a 圖)。在運用電流感測之處,此可方便地實施以感測跨接一 電流感測電阻器之電壓。 15 在第2&圖之電路操做中,將輸入直流電壓(典型上相對 地高)轉換成一輸出直流電壓(典型上在適用於消費型電子 裝置之範圍),譬如介於約5V和20V之間。在一些較佳實施 例中,直流輸出與直流輸入隔絕,如第2a圖中所顯示;其 他實施例♦可運用次級端回授,這樣的情況中可包括一組 2〇光器來提供顺向轉換器之主要與次級端之間的阻隔。 一般順向轉換器具有一些優勢,包括相對較小的尺寸 與低成本。然而傳統上它們難以調節,而構件,特別是開 關,在某些負載條件下及啟動時易於故障。理論上它們I 有良好的功效,因為它們可在共振模式下運作,僅管傳統 25 200807849 的自由輪轉或返馳式二極體會防止達到共振。再者,傳統 上二振之達成需小心的選擇允許自我共振之構件值,但此 定了構件之使用容限較吃緊,其較昂貴又增加了製造上 的困難度。 我們所述配置運用一控制器210來控制開關212之時脈 、截止,此亦允許一運用種種具有優勢之技術。因此 我們下面將說明第乃圖之順向轉換器如何能在一構件值範 圍下了罪地運作’電流限制和啟動控制如果被運作(這兩者 均有助於達到可靠的操作及保護開關212), 以及切換時脈 1〇如果控制在一不連續共振模式下來達到調節。 第2b圖繪示第2a圖之控制器21〇之一範例實施例。一比 較器250比較一感測電壓與一參考電壓,譬如零伏特,來提 供一控制信號252至一開關控制單元256以控制開關212導 通。比較裔250之輸出亦提供至一計時器258,其時脈始於 15 一導通脈波寬度。當計時器暫停時一信號被提供於一第二 控制線254上至開關控制單元256來控制開關212截止。開關 控制單元256可包含,譬如,一設定_重設閂以及一介面電 路來驅動一雙極電晶體之基極、及/或一 MOS電晶體之閘 極。較佳地電路亦包括一〇R閘260和來自一過電流保護線 20之一輸入262。此可藉由比較一電流感測輸入與界定一電流 限制臨界之一參考位準而產生。當過電流保護輸入262變成 主動,開關控制單元256馬上被控制開關212截止,因此實 施週期間電流限制控制 第3 a和3 b圖顯示例說第2圖之順向轉換器之操作的範 26 200807849 例波形。這些圖式中(及之後類似之圖式),波形300表示驅 動電壓導通一雙極電晶體開關之基極,波形3〇2顯示一集極 電流’其實質等於經由順向轉換器200之變壓器206之主要 繞組204之一電流。主要端電流因此控制變壓器2〇6中之通 5 量並因此亦控制次級端電流。波形304顯示雙極電晶體開關 之集極端上的一電壓,當開關導通,此等於變壓器2〇6之主 要繞組204上之電壓的電壓被反映於變壓器之次級繞組2〇8 上。當開關被關閉’變壓器主要端内之電流驅動次級端中 之一電流,因此經由整流器220充電整平電容器222 ;當開 10 關被打開,順向轉換器之主要端停止驅動次級端而電力從 整平電容器222被供應到輸出端218(而二極體220截止)。在 地3a和3b圖之波形中波形300的規模為每一部份500mv,波 形302為每一部份mA而波形304係每一部份100V。第3a圖中 之驅動波形頻率將近59KHz ;第3b圖中之驅動波形具有將 5 近48·4ΚΗζ之頻率。波形300之近觀察顯示驅動信號之截止 未完全清除,肇因於雙極開關之特性;波形302與3〇4相對 應0 在順向電力轉換器之較佳實施例中我們描述,在一能 里轉移之後週期變壓器被重設(故其不被磁化”在重設期 間,相位電流以當開關212(一般為一功率電晶體)被導通時 的反方向流入變壓器主要繞組。變壓器之電感共振動作和 包谷态214被用來執行此重設開關212 一旦被截止,有—半 4下波在電容器214(波形3〇4)之底盤。此底盤上之電壓藉電 感器之動作驅動電源供應電壓,使得在變壓器之示波電壓 27 200807849 頂部主要與順向能量轉移期間方向相反。(在此點時有一相 對較高的電壓在開關212上,第3a圖之範例波形304將近 550V,遠大於輸入電壓,而開關因此因能承受這樣的一電 壓不至崩潰)。在電容器放電而開關212上之電壓下回到0 5 時,變壓器中之電流主要與電源供應週期之一順向能量轉 移部份期間的電流方向相反,因此變壓器被重設。若開關 在此時不被導通,共振持續漸小共振峰串(見之後的第11 圖)。較佳地開關212在開關上之電壓實質上為小小時被導 通,即接近0V時(第3圖;第11圖)。 10 第4圖顯示用於第2a圖之不連續共振順向轉換器之一 等效電路。此顯示雙極電晶體開關、輸出整流器、與變壓 器之寄生電容(Cp)、以及共振電容器(Cr)、一磁化電感 (Lmag),其表示儲存在一變壓器之能量、以及一洩露電感 (Lleak),其表示在變壓器之主要與次級繞組之間的洩露電感 15 (由由一些通量線洩露鏈結到主要與次級繞組使得它們作 用如一電感器)。通常,但非必然,Cr遠大於Cp。在操作上 L m a g保持主要電流流入C r來造成共振,而次級電流將近匹配 主要電流。洩露電感提供一電流限制程度,特別有助於在 整平電容器呈一短路狀態時減少啟動時之過負載。 20 第5a至5d圖顯示共振不連續順向轉換器之另類拓樸結 構。第5a圖中之共振電容器被耦接至開關(在此例中,顯示 為一雙極電晶體開關)。第5b圖中之共振電容器係在轉換器 之輸出端上,更特別地是連接於變壓器之次級繞組。第5c 圖中明顯地包括與輸出整流器串聯之一小的電感器。第5d 28 200807849 圖繪示一順向轉換器結構,其中運用有一自動變壓器。 在實施例中,變壓器由變壓器波形之共振部份重設: 用以將磁化放電至共振電容器中之電流之變壓器去磁化並 共振地放電。另外或另類地變壓器可藉由與一整流器串聯 5耦接之一輔助繞纟且來重設。第6a圖顯示這種重設電路之一 範例,其中變壓器之一主要端輔助繞組與變壓器之主要與 次級繞組相較具有一相對或相反之極性。在開關之截止期 期間,與輔助繞組串聯之一個二極體變成順向偏壓且將電 力傳導回到直流輸入(使得此技術為不分散的)。第仍和6〇 10 圖顯示另類組配,其中輔助繞組係置於變壓器之次級端 上,且(再次)具有與主要與次級繞組相反之一極性(次級端 上二極體被連至繞組之相對側)。在這些範例中,辅助繞組 與一整流器串聯連接並跨接次級繞組和整流器,以及選擇 性地連接電感器於順向轉換器之輸出端。 15 再_人芩考第2和3圖,比較波形304和300可見波形304 之後在驅動信號300至雙極電晶體開關令開關導通之前有 -短的期間進如實質零伏特。若有充分的延驰,進一步的 共振最終可見於波形3〇4中,但仍然應瞭解開關可能再次被 mi ^有4期圍’因此開關之控制可藉由檢測到 20波形304之-實質零電壓位準且在其共振半期之後,然後在 令開關導通之前等待—延遲(其可為零)。此電路操作之容受 度根據零_電壓或共振波谷城,允許__(更特別地, 開關截止¥間)長件足以應付—共振解範圍及共振構件 值。 29 200807849 我們接下來考量順向轉換器之啟動。在啟動時電源供 應輸出呈現為短路。不像連續順向轉換器,其運用一返驰 式二極體’依據RDFC上出現之負載,不足量之能量可被轉 移到轉換裔之輪出來充電輸出電容器。這特別是運用電流 5限制的一個問題,因為超高電流會出現在變壓器之主要端 上,而電流限制可令開關截止驅動信號,利用特定負載可 使輸出電容器可被充電。 第7a圖繪示顯示藉由電流限制在啟動電源供應輸出 (電壓)期間可能上升不到正確值之困難。檢視集極電壓波形 1〇亦顯然出當開_止時(因為次級端輸出係逆向反射)有一 非令構件,且此非零集極電壓可被感測來識別此啟動條 件,以及電流限制、過負載、及短路,如果想要的話/、 15 20 、不連續共振順向轉換器之較佳實施例中,順向轉換器 被控制於啟動時在加頻率模式下操作,譬如操作以一 正b員率的5或1G倍。此可II由在啟動時選擇—簡單振盈器 ,可感測集極電壓並用來控制開關導通以致用-較高頻 板式之知作來實施。以—增加頻率操作·c會增加轉移 輸出之^*何同時仍倾電源卩。第%圖㈣此增加 操作(時間劃分較第_ 貝率 啟θ f的短),且可發現在此高頻率 的着。㈣電贿時間為 ㈣換為增加到-正常操作輸出電壓。 制系ΐ們接著說明用於—不連續共振順向轉換11之電流限 ,其操作在一共振模 RDFC—旦被啟動且達到穩態操作 30 200807849 式下,伴隨追著輸入(電壓)之-輸出(電堡)。然而若施加一 =栽¥ ’特別是㈣在_固定頻率時,輸出電流及開關 電流會大幅地增加而電路可能受損。因此較理想的是感測 我們所說明之RDFC與控制器中之開關電流,能縮短驅動來 5控制一過負載條件下之驅動電流。 第_顯示-RDFC之—實施例,其包括具有電流感測 端⑻以及集極電壓(Sc)以及直流輸入電壓(sdc)感測輸入 之-控制器。第8b圖繪示過負載期間—順向轉換器之波 形,其中可發現由於輸出電路負載使得集極電壓波形不再 Π)正確地共振(半期之第-部份被截形)。為了比較,第&圖顯 示在無負載條件下之一順向轉換器。 我們之前已說明如何實施過電流保護。然而有些情況 下一固定電流限制轉換器會降低轉移到輸出之功率,此接 著變降低輸出電壓而增加輸出電流,這會造成轉換器輸出 15電壓大幅下降,即使是在負載被移除時。在此情況下順向 轉換器可能無法復原。解決此等—或更多問題的策略可被 運用。譬如-增加頻率重新啟動技術可被運用,如前述般 有效地使輸出電壓回到其正常運作位準。另外或另類地一 輸出端電感可被運用、及/或變壓器之汽露電感可被控制卜 2〇般被允許提高)來提供-電流限制效果。又,電流限制可被 改變,隨脈波寬度減少增加電流限制。後者的方式會在之 後做更詳細的說明。 更5羊細地,在某些應用中,例如一定電流負載,輸出 電壓可進入-種連續下降的狀態,且此狀態下電源供應無 31 200807849 以類似於前述之方式在啟動期間増加 以此方至負载之電力可被增加,因而增加輪出電壓。 :'、可柄節同時限制電流於一減少輪出電 或-串連電感亦可用來丢掉一部份輸出電堡於此電 隻 10 脈波2向轉換器在一電流限制模式下運作時仍可能藉隨 =又之減少增加可允許的開關電流來調節輪出電流。 此I安全地實現於我們所說明的-RDFC類型,因為傷害轉 換風險隨著脈波寬度而降低。結合此技術與變壓器之 洩露電感及/或-串聯輸出電感能使輸出電流隨輸出電壓 下=被勒。因此,大致上說來,此技術之功效係增加脈 波見度來造成一減少的電流限制。 我們現在進-步討論可用來補償使用具有相對較廣容 忍度之構件的技術。製造具有較小容忍度主要磁化電感之 15 -變壓器是很困難的。其中—種技術係清除並緊附核心, 但這種技術很昂貴。一小容忍度共振電容器亦很昂貴。我 們之W已說明控制器中之一固定頻率振堡器能如何運用與 適合的工作週期選擇,來補償這些構件中增加的容忍 度。另一技術包含藉由控制開關使其在主要(電壓)波形之零 20電壓相位期間被導通來補償增加的容忍度 。如前述,在開 關电壓將近零伏特時有一最後限期(現實中,電壓可稍微低 於地電位)。在控制器之零電壓切換(ZFS)實施例中,電源開 關在此時期被導通。第知至允圖繪示不同的開關驅動有關 集極電壓波形之範例時脈。 32 200807849 參考第9a圖,此顯示一範例,复 但其中開_理想狀態晚導通。“此較佳^壓切換, 導通,如第9b圖所示,這可造成非 7開關太早 損失及電磁干擾綱。第知圖顯示開二:’造成切換 壓波形之-較佳時脈。 樣_有關於集極電 完美 10 15 20 第_讀⑽脈謂由下w錢行㈣來達到: 在集極電μ為料㈣並令開關響應於此而導冑 極電麼降至零時、或電壓到達零之後_小段_、^ = 集極電壓再次開始攀升時。第9c圖之時脈繪示_「完 共振開關之時脈,其開關只要集極電_達零就導^ 我們接著討論調節一 RDFC之輸出電壓。通;二效果 很貧乏,肇於相對較高的誠電感與構件(繞組)電阻。此結 果即輸出電魏著财的貞載抛㈣轉鮮町降。再 者,-RDFC在補償輸入電壓變異上可能有困難& ,且通常 輸出電壓追著輸人電壓。這會是流出_栅狀總電源之順向 轉換器中的—種狀的問題,因為總電壓會經常大幅地變 化。然而前述控制器實施適用於脈波寬度與脈波頻率控制 =貫務來調節-RDFC輸出電壓。更特別的是,在低輪入或 阿負载條件之—或^者顧增加脈波寬度及域增加頻率 可改良調節。 第l〇a圖顯示另-可用於輸出電壓調節之技術。在此配 置中’-輸人電壓轉·,無論是—交流轉纽或—直流 轉^轉換$,個來提供_直流輸人電源供應至順向轉 、且其係自順向轉換器之次級端回饋。為了調節輸出 33 200807849 電壓。輪入轉換器可包含-升壓或降壓或PFC(功率因數校 正)級。 第10b圖繪示在-多相位組配中使用兩個功率變壓哭 來改良輪出調節。在第i 〇 b圖之配置中開關受到控制,使得 5各開關僅在其他開關截止時被驅動,建立互補但不重疊之 驅動波形。此技術對於操作於相對高頻而調節貧乏之小型 順向轉換器很有用。 參考第11圖,我們現在說明-些用來實施一rdfc之低 負載及/或待機模式操作的技術。在一些較佳實施例中,我 10 們運用脈波-跳躍技術。 一工作於最大頻率之RDFC電源供應傳統上在低負載 時沒有效率且具有高待機功率損耗。因此當一rdfc上之負 載減少時,效率降低,尤其是在無負載時效能很低。此主 要是由高切換損失和高磁化電流等所造成。然而藉由控制 15導通和截止時間可以減少功率損耗,特別是藉由運用前述 之PWM和PFM技術,此外或另親,跳躍一週期的脈波到 等於許多倍的週期。亦較佳地控制這些脈波之時脈來與共 振波形中之波谷同步,使得RDFC開關在之後的波谷類共 振0 因此在我們系統之實務上,我們藉由在界定一更短的 脈波之前令開關截止來減小脈波之寬度,這樣可以降低負 載功率損耗。另外或另類地我們針對接下來的脈波引用一 延遲來令開關較慢導通,跳躍一或更多開關驅動脈波。此 亦繪於弟11圖’其中驅動脈波被延遲來跳過一或更多共振 34 200807849 週期’如圖例中開關(集極)電壓所表示者。導通時隨共振開 關波形麵制為零伏特開關(集極)電流中有 一突尖,而第11 圖亦、、曰不共振波谷切換,其中開關在共振波形之-波谷點 被V通來減少損失。這些技術可實施 以如前述之一控制 5 :言如藉由如第8a圖所示之一感測配置,或另類地利用 第12圖中所不之電壓感測,譬如,利用第2b圖顯示之一控 制配置。一降低電力模式,例如一脈波寬度調變(減少)或脈 波跳躍模式可被-事件觸發,譬如—或更多控制器(晶片) 電源供應降到低於一預設值;在一第二共振(見第_)之 10後,或在一預定時間(驅動脈波之間)之後。RDFC中之一脈 波跳躍技術,例如前述者,在低負載時或在待機時可增加 效率並降低電力損耗。脈波跳躍技術亦能在低負載時快速 地響應。 又另一技術中,我們運用之系統實務上,特別是在包 15含一(雙極)電晶體之開關,係用來限制開關電流而非操作電 晶體於-線性區域。此防止開關過熱。實務上當開關被截 止日寸,開關上之主要端電壓有一突升,此可被感測及控制, 4如藉由導通電晶體來限制過衝。因此,譬如,開關可在 啟動期間部份地導通來補捉及限制電壓過衝。 20 我們接著說明一些適用於一離線(插電)RDFC轉換器 之漣波去除技術。參考第12圖,此顯示一總漣波電壓可如 何在一共振不連續順向轉換器中被感測。如圖可見,輸入 電壓漣波可由許多點感測到,包括輸入直流匯流排、集極 電壓、一變壓器繞組電壓及/或輸出電壓。在實施例中少量 35 200807849The lower can be increased as the drive pulse width decreases or the drive frequency increases. As described in the previous L, the output of the forward converter can be packaged. Small «, and capacity _ in - discontinuous resonance mode, and including this; over load output current, _ is __ section) 疋 疋 由 by facilitating the adjustment of the output current, as described above. In an embodiment, this Rayaway inductance can be leaked or parasitic in the circuit. 20 200807849 In an embodiment, the transformer provides a sense of inductance to the converter, particularly the transformer (10) inductance. The device can be configured to increase a leakage inductance for a desired output inductance value. '2 to the power conversion transfer often occurs - the type of _ is then to ensure the guilty start. This is because the forward converter output forms the same short circuit at startup, which can potentially damage the power supply switch where a current limit configuration is located or trigger a current limit because (4) the output voltage reaches its proper value. The forward converter embodiment we describe employs a configuration to facilitate the management of a forward converter startup in a controlled manner to turn the power switch on and off, and in particular, to use one of the drive signals. Increase the power of the switch to start. This causes the converter to leave its operating resonant mode when it starts and causes more power to be transferred to the output while still protecting the power switch. The startup condition can be detected directly at the primary end of the forward converter or indirectly by using one of the forward converters. In some particularly preferred embodiments, the aforementioned controller is implemented as a single integrated circuit. This 1C can implement one or more control strategies as previously described. However, in some preferred embodiments of 1C, the power switch is not on the wafer for compatibility reasons. Therefore, in another aspect of the invention, a controller for controlling a forward converter is provided for converting an input DC voltage into an output DC voltage, the converter comprising: first and a DC input; a transformer having a polarity-matched primary and secondary winding; a controllable switch for switching power from the DC input through the primary winding of the transformer, the controllable switch and the primary winding of the transformer Between the first and second DC voltage inputs; the first and second DC voltage outputs; a rectifier coupled to the secondary winding of the transformer, the rectifier and the transformer The winding is coupled in series between the first and second DC voltage outputs; and has a leveling capacitor coupled to a first connection node for receiving a first connection of one of the DCs from the rectifier, The first connection node is coupled to the first DC voltage output, the leveling capacitor having a second connection coupled to the second DC voltage output; The controller has a control coupled to the controllable switch and is configured to control an output of the switch such that a voltage waveform on the secondary winding has a voltage during the switch 10 being turned on and current flowing into the first connection node a first portion, and having a second substantial resonance portion during the off period of the switch; and wherein substantially no current flows into the first connection node during the second portion of the voltage waveform; thereby the forward conversion The device can be controlled by the controller to operate in a discontinuous forward voltage conversion mode. Preferably, the controller is implemented as described above on a single integrated circuit. A still further aspect of the present invention provides a method of controlling a forward converter operating in a discontinuous resonant mode by controlling a controllable (power) switch such that a voltage waveform on the secondary winding has a first In part, the switch is turned on and current flows into the first connection node and a second 20 substantial resonance portion, during which the switch is turned off and substantially no current flows into the first connection node during the second portion of the voltage waveform. According to another aspect of the present invention, a controller for a resonant discontinuous forward converter (RDFC) is provided, the forward converter including a transformer having polarity-matched first and second windings and for switching DC to 12 200807849 A switch of the first winding of the transformer, the converter further having a DC output coupled to the second winding of the 忒, the voltage exchanger, wherein the control piano has two modes ··- a mode that is used to switch the DC power to a frequency that is substantially synchronized with the resonant frequency of one of the RDFCs during operation of the switch, such that the DC output is powered, and a first The reduced power mode of operation during which the drive of the switch is controlled to increase the proportion of time during which the switch is turned off. In some preferred embodiments, the switch drive includes a pulse and the pulse width (continuous) is reduced, in the second reduced power mode of operation. One or more of the resonant frequency cycles of the switch are skipped in the reduced power mode of operation. In the latter case, when the switch is subsequently turned on, to further increase the efficiency of the RDFC turn-on, the timing is substantially synchronized with a turn-on point, more specifically a valley of one of the resonant waveforms of the RDFC. In some preferred embodiments, the controller is configured to automatically sense a low load condition and to select a second reduced power mode of operation in response thereto. For example, the controller can sense a reduced load condition by sensing one of the power supplies to the control state, where the controller is applied as a one-piece circuit to one of the 1C voltage sources. Alternatively or additionally, the controller may select to reduce the power mode by sensing the operating clock of the RDFC, particularly during the power-on 20 off period (cycles above one cycle). Further operations for identifying reduced load conditions include sensing at one of the outputs of the RDFC (e.g., utilizing a current sense resistor at the output of the forward converter) and sensing by one of the auxiliary windings on the transformer. In some particularly preferred embodiments, the controller is configured to control the drive of switch 13 200807849 such that the switch is turned on only when the voltage on the switch is near 〇¥. (In a practical example, the voltage on the switch may in fact never be 〇v, because, for example, because there is a diode drop); this is especially useful. In some preferred embodiments, the second reduced power mode of operation includes a 5 RDFC standby mode. According to another aspect of the present invention, a controller for a plug-in resonant discontinuous forward converter (RDFC) is provided, the forward converter including a transformer having polarity-matched first and second windings, and Switching to a switch of the direct current of the first winding, wherein the converter further has a DC output coupled to the second winding of the transformer, and wherein the DC system to the first winding Deriving from a total power supply and including one component of total chopping, the controller includes: a chopper sensing input for sensing the total chopping, and lightly connecting to the chopping sensing input and having a clock control module for controlling an output of one of the drive signals of the switch, the drive 15 includes a pulse wave having a pass period for driving the switch to be turned on, and a pulse wave for driving the switch to cut off a pulse of a deadline; and wherein the clock control module is configured to responsive to the second total chopping to change one or both of a width and a frequency of the pulse to suppress the DC The chopping in the output One of the ingredients. 20 The chopper sensing input senses household or grid total chopping at most points, including, but not limited to, the DC output of the RDFC, the switch, and an auxiliary winding from the transformed state of rdfC. Preferably, the controller also includes a further sense input for adjusting the DC output of the converter. Preferably, the clock control module output includes first and second output lines for respectively controlling the switch guide 14 200807849 on and off; the controller preferably further includes a switch control module responsive to the output lines for controlling The switch turns on or off an off. A method for suppressing chopping in a plug-in resonant discontinuous forward converter (RDFC) including first and second windings having polarity matching is provided in a related aspect of the invention a transformer, and a switch for switching to a direct current of the first winding of the transformer, the converter further having a DC output coupled to the second winding of the transformer, the method comprising: sensing the RDFC a component of the total chopping wave in a signal; and a pulse width of one of the driving signals of the switch and a frequency of a pulse wave of 10 of which are either " or both to suppress the continuous wave. In another yet another aspect of the invention, a controller for a resonant discontinuous forward converter (RDFC) is provided, the RDFc comprising a transformer and a power switch for switching to the DC power of the transformer, wherein the control The system is configured to limit one of the currents in the switch during startup of the RDFC. In an embodiment, the switch comprises a transistor, particularly a bipolar transistor, and the current limit can comprise operating the transistor in a non-linear region. Additionally or alternatively, the controller can be configured to increase the frequency of one of the control signals to initiate switching to limit current during this time. The frequency can be increased by a factor, for example, 2, 5, 10 or more above a normal operating frequency. Therefore, in the actual implementation, the controller can be configured to control the rainbow DC to make it non-resonant at startup. The start-up solution can include a fixed frequency or a frequency that is determined by the _ 4 Lu number and 疋. In yet another aspect of the invention, 56. a controller for a resonant discontinuous forward converter (pin c), the rdfc comprising a transformer 15 200807849 and a power switch for switching to the DC power of the transformer, wherein the open relationship Switching to power to one of the windings of the transformer, wherein the controller includes a system for sensing a voltage in the winding of the transformer and controlling the portion of the switch to conduct in response to the sensing. 5 In this embodiment, the transformer includes an input winding and an output winding that are coupled to switch the power to the input winding of the transformer. At one of the nodes on the input winding to which the switch is connected, an imminent voltage rise occurs when the switch is turned off (generally in response to the input and output winding ends of the transformer being inconsistent), and this voltage overshoot can be partially turned on. The switch is controlled and limited by 10, in the effect of sensing and overshooting. Therefore, at another level of the invention, there is provided a method of controlling a resonant discontinuous forward converter (RDFC), the RDFC comprising a transformer and a power switch for switching to the DC power of the transformer, the method comprising sensing the transformer A voltage on the winding and a step of controlling the switch to be turned on 15 in response to the sensing to limit voltage overshoot. In another aspect of the invention, there is provided a current limiting method in a resonant discontinuous forward converter, the forward converter comprising a transformer having one of a polarity matched first and second windings, and for switching to a switch of the direct current of the first winding of the transformer, the converter further having a DC output coupled to one of the second windings of the transformer, the method comprising detecting a current limiting condition; and responsive to the detecting increasing to One of the switches controls a frequency of the signal. In a related aspect of the invention, a controller for a resonant discontinuous forward converter (RDFC), a transformer having a polarity-matched first and second 16 200807849 windings, and a switch for switching to the transformer are provided a switch of the direct current of the first winding, the converter further having a DC output coupled to the second winding of the transformer, the controller comprising: means for detecting a current limiting condition; and responsive to the A means of detecting a frequency that is added to one of the switches to control the 5-signal. The present invention still further provides a controller for a resonant discontinuous forward converter (RDFC) having one or more signals for sensing one or more signals from the resonant discontinuous forward converter a multi-input, the controller further comprising: a system for analyzing the one or more sensed signals, 10 for determining a turn-on and a turn-off time for one of the RDFC power switches; and an output for turning on the determination A drive signal is provided to the switch with the cutoff time. In yet another related aspect of the invention, a method of controlling a resonant discontinuous forward converter is provided, the forward converter comprising a transformer having 15 polarity-matched first and second windings, and for switching to the a switch of a direct current of the first winding of the transformer, the converter further having a direct current output coupled to the second winding of the transformer, the method comprising sensing a signal from one of the controllers having one or more inputs The resonant discontinuous forward converter converts one or more signals, and analyzes the one or more sensed signals to determine a turn-on and turn-off time of the switch, and provides a driving signal according to the determined turn-on and turn-off times Give the switch. In yet another aspect of the invention, a method of operating a resonant discontinuous forward converter is provided such that the resonant discontinuous forward converter has lower sensitivity and tolerates one or more of the resonant discontinuous forward converters Resonance 17 200807849 The method comprises a power switch of a Xiang-spontaneous recorder drive _ resonance discontinuous forward converter, one of which is substantially fixed frequency 盥 one or both of which are selected when the switch is substantially i In order for the volts to make the switch turned on. 10 15 20 "This method is only used in this case, the RDFC is configured to operate in a real-to-voltage switching mode, for - different (resonant) component values. This causes a reduction - reality has a low component count and Therefore, it is potentially for the Curry County to reduce the "industry practice, (4) in this (4) a, the (main) variation of the magnetic inductance and the resonance capacitor to ensure high efficiency, thus further providing 70. - Kind to stay. - a controller of the resonant discontinuous forward converter, such that the resonance has a lower sensitivity to the conversion H and accommodates a resonant discontinuity - or more resonant components, the controller is included to drive the Photographing the continuous forward converter - the power switch - the spontaneous oscillator; the vibrator - the substantial solid frequency and - the working period of the middle, the middle = the selected 'W off is essentially at the other - tree level The towel provides a controller for the forward converter, the transformer includes a transformer having a polarity of the first and second windings, and a switch for switching to the variable - The DC of the winding - the switch 'the converter is more = 11 the second winding of the transformer _ - DC output, the controller ^ controls the forward converter to operate in a controlled oscillation mode, in the basin, with The inverter has an operation cycle including current flowing into the transformer: a conversion 18200807849 and a first (conduction) portion of the second winding, and a substantial resonance voltage waveform appearing in the first winding of the transformer and the switch One of the second connections a portion, wherein the controller has at least one sensed signal input for sensing a signal from one of the resonant discontinuous forward converters, and 5 is responsive to the sensed signal to control the switch to operate the forward direction The converter is output in one of the controlled oscillation modes. The sensed signal in the preferred embodiment is responsive to one of the energy levels in the transformer. Preferably, the controller is implemented using a switch control module having one of the first and second switch control inputs to receive individual turn-on and turn-off control signals. Preferably, these are driven by a comparator which compares the sensed signal with a reference; preferably the other is also driven by the comparator output, but delayed, in particular by a variable pulse width Timer. In this manner, the switch can be controlled to conduct, when one of the voltages sensed on the switch reaches the reference voltage, and is controlled to be turned off after a predetermined or variable time. In some of the more preferred embodiments, the cut-off control signal is also gated with an overcurrent protection signal such that when an overcurrent condition is detected, the switch can be controlled to turn off immediately. In other configurations, the on and off of the switches can be separately controlled; alternatively, the on and off of the switches can each be controlled by sensing a voltage and/or current on the RDFC input. In the embodiment, the switch is turned on for a time (which may be a fixed period of time, or may be zero) when the voltage substantially reaches zero, and/or in response to sensing the first (input) winding through the transformer A current sensing signal (voltage) of the current. In an embodiment, the switch is turned off after a fixed or variable on-time, and/or in response to a voltage sensed at the input of the RDFC and/or electricity 19 200807849 / melon in the case, the controller may respond Signaling more than one from the RDFC. In an embodiment, the RDFC lacks one of the grids in parallel with the output rectifier and instead the RDFC is assembled to achieve resonance without any capacitance other than the internal parasitic capacitance associated with the rectifier. 5 RDFC can be used in conjunction with a total power switch. In such an embodiment, a high κ C can be derived directly from the grid-like total power source, such as by a bridge rectifier, which provides an input-to-RDFC that is combined to produce a lower DC output voltage, such as less than 50V, 4〇v, 3〇v, 2〇v or ·. In some preferred embodiments, the controller of the present invention is implemented in a 10 single-chip integrated circuit, optionally including a power switch. One of the aforementioned controllers can be implemented as an analog or digital circuit. Therefore, when the controller is mainly or entirely implemented in a number circuit, the invention further provides a carrier for carrying a control code, such as a buffer (scratch transfer layer) or a system C defining hardware to implement control. Device. According to still another aspect of the present invention, there is provided a forward-to-direct power converter comprising: - an input; a transformer having a primary and a primary winding; and a combination to replace power transmission from the wheel Passing through a power switch of the primary winding; consuming one of the output of the secondary winding; and a control system having a sense wheeling and being configured to control the switch-switching clock to respond Resisting power from the forward converter from a sensed signal from the sense input; and wherein the sense input is coupled to receive the sensed signal from a primary end of the forward converter. The sensing signal providing an input to the control system may include a voltage and/or current sensing signal. The control system can adjust one of the forward power converters. 20 200807849 Output voltage and / or an output current. The present invention also provides a controller for a primary end sensing, particularly as previously described. Looking for ~ = The skilled person can understand that the aforementioned _discontinuous resonance is ::: with:: road topology, including but not limited to those described later. For example, 'Transformer can contain a brief description of the diagram... Example: Γ 这些 这些 这些 Γ Γ Γ 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些 这些To the converter example. The first ice_shows the implementation of a discontinuous resonance forward converter, respectively, and the example clock and control configuration of one of the converters of Fig. 2a; the 3a and 3b diagrams show the forward converter of Fig. 2a from _ I7〇v DC wheel 15 waveform; input supply provides 1 A and 2 A output current operation __ Example Μ · Figure 4 shows a forward converter power supply according to one embodiment of the present invention An equivalent circuit model; 5a-5d shows an alternative topology of a forward converter in accordance with an embodiment of the present invention; FIGS. 6a-6c illustrate the use of an auxiliary winding to reset a forward converter in accordance with an embodiment of the present invention. An example of a transformer. Figures 7a and 7b respectively show a forward converter that does not have and has a high frequency control waveform during startup; Figures 8a-8c show an input of a discontinuous resonance forward 21 according to one of the inventions 2008 20084949 converter embodiment Sensing connection configuration and one of the forward converters under overload and no load conditions; Figures 9a-9c show examples of late, early, and target waveform clocks of a forward converter; 5 1st The a and 10 b diagrams show the adjustment of one of the forward converters and the multiphase forward converter circuit, respectively, using the secondary side feedback; Figure 11 shows the waveform of the resonant discontinuous forward converter, which uses the pulse jump An example waveform of a switching drive pulse, a switch (collector) current, and a switch (collector) voltage is illustrated for the transition to the resonant valley; and FIG. 12 shows an exemplary resonant discontinuous forward converter The voltage sensing circuit technology, especially the chopping reduction. L Embodiment: J Detailed Description of Preferred Embodiments In this specification, we describe controlling a resonant discontinuous forward converter. 15 In an example RDFC, the power to one of the primary or input windings of a transformer is switched, and one of the secondary or output windings of the transformer matching the polarity of the primary winding is coupled to a rectifier that provides DC to a leveling capacitor The DC power is supplied to the RDFC output from this connection node. A voltage waveform on the secondary winding of the transformer has a first portion during which the switch conducts and current flows into the junction node and the second substantial resonance portion during which both the switch and the rectifier are turned off. Substantially no current flows into the connection node during the voltage waveform of the second part (except from the leveling capacitor). In design, we describe a connection between the rectifier and the connection node, which can include a small inductor (such as less than 5% of the main end magneto 22 200807849 sense) 'but the actual resonance of the second resonance part of the waveform No current flows into this inductor during this period and does not require the use of a large plug in the continuous forward converter. There is no need to connect - the capacitor crosses the rectifier to reach resonance; in an embodiment, our resonance essentially spans only the switch, not including the secondary diode. In the second embodiment, we use the magnetic inductance of the transformer with the additional grid on the main end to achieve the pachining in the off period. In some preferred practices, the RDFC is configured for AC-to-DC conversion and thus includes an AC-to-DC converter, such as one of the bridge rectifiers on the primary side. In some specific preferred practices, the RDFC^^, plug-in type 10, and the main terminal is powered by a DC voltage (such as greater than 7 (Wdc, l〇〇Vdc, 150V DC, or 200Vdc), while The secondary side DC voltage is very low (for example, less than 20V DC or lOVdc). In the embodiment, we use zero voltage switching on the main terminal (ie, a main terminal switch is used when the voltage on the switch is close to zero volts). Turn on), but we ignore the loss of the secondary diode loss at the time of switching. We will also describe the technique used to implement a resonant discontinuous forward converter (RDFC) that uses a control system in a controlled manner. Turning one of the RDFC's power switches on and off. As mentioned above, the control system can operate in an uncontrolled fixed frequency mode, or the control system can sense from a 20 or more inputs and respond to this sensing to determine when The power switch is turned on and off, for example, to implement pulse width and/or frequency modulation. This facilitates the adjustment of the RDFC, and the details can be implemented using an algorithm. A system that uses a control system to operate the RDFC compensation circuit. change And operating in a zero voltage switching (ZVS) mode. The converter can also control the switching frequency during startup and/or current limiting 23 200807849 to protect the power switch and increase the energy transferred to the load. The control system preferably utilizes a control 1 (: (integrated circuit) implementation. As mentioned before, the operation of the foot c does not require a free rotation or flyback diode n with or without an output inductor. However, if the output inductor 5 Small enough to ensure that the forward converter operates in a discontinuous mode and is substantially at or near resonance. Referring now to Figure 2a, this shows a discontinuous resonant forward converter 2()() according to the invention. Example. Figure 2b shows an example clock and control system 21〇 for the forward converter of Figure 1. 10 I test 2a® 'This display—completely resonant discontinuous mode forward converter 200' There is a DC input 202 coupled to the main winding 204 of the transformer 2〇6 of one of the series and one of the power switches 212. A resonant capacitor 214 is connected across the main winding of the press and the DC input 2〇2 is provided. Leveling capacitor write 216. Forward conversion At the output of the converter, one of the secondary windings 2〇8 of the transformer is supplied with power from a rectifier 220 to a pair of DC output terminals 218. A leveling capacitor 222 is connected across the DC output terminal 218 to the junction of the rectifier 220. The output node, the leveling capacitor 222 and one of the connections to the direct current output 218 are labeled "X." The current entering the node X flows into the leveling capacitor 222 or the positive flattening 222 and the output 218. Discontinuous, relative to the circuit shown in Figure 20. Switch 212 can include a bipolar or MOS transistor, such as a MOSFET, or IGBT, or some other device. The rectifier 22 can be implemented as a diode or by a MOS transistor. Resonant capacitor 214 may comprise a discrete component, or may be provided entirely by parasitic capacitance, or may comprise either of the two 2008 200849 combinations. The switch 212 is controlled by a controller 210. The open controller 21 includes a clock control module 210a and a switch control module 210b. The clock control module provides a switch conduction and switch off signal 210c to the switch control module 21. b. The 5-pulse control module can have one or more sensing inputs, such as a voltage sensing input and one of the current sensing inputs, or such sensing action can be omitted, and the clock control module 210a It is essentially operable independently of the sensing conditions of any forward converter circuit. Where voltage sensing is applied, the voltage across the main winding of the transformer can be sensed, either directly or indirectly. For example, the voltage can be sensed by a connection to one of the junctions between the main winding and the switch as shown; alternatively, for example, a sense voltage can be derived from one of the auxiliary windings of the transformer (not shown in Figure 2a). ). Where current sensing is utilized, this can be conveniently implemented to sense the voltage across a current sensing resistor. 15 In the circuit operation of the 2& diagram, the input DC voltage (typically relatively high) is converted to an output DC voltage (typically in the range suitable for consumer electronics), such as between approximately 5V and 20V. between. In some preferred embodiments, the DC output is isolated from the DC input, as shown in Figure 2a; other embodiments ♦ may utilize secondary side feedback, in which case a set of 2 dimmers may be included to provide A barrier to the primary and secondary ends of the converter. General forward converters have several advantages, including relatively small size and low cost. Traditionally, however, they are difficult to adjust, and components, particularly switches, are prone to failure under certain load conditions and startup. In theory, they have good performance because they operate in resonant mode, and the freewheeling or flyback diode of the conventional 25 200807849 prevents resonance. Furthermore, the traditional strike-off must be carefully selected to allow self-resonant component values, but this limits the use tolerance of the components, which is more expensive and increases manufacturing difficulties. Our configuration utilizes a controller 210 to control the clock and cutoff of switch 212, which also allows for the use of a variety of advantageous techniques. Therefore, we will explain below how the forward converter of the first graph can operate under the sinus of a component value range. 'The current limit and start control are operated if both are helpful to achieve reliable operation and protection switch 212. ), and switching the clock 1〇 if the control is reached in a discontinuous resonance mode. Figure 2b illustrates an exemplary embodiment of the controller 21A of Figure 2a. A comparator 250 compares a sense voltage to a reference voltage, such as zero volts, to provide a control signal 252 to a switch control unit 256 to control the switch 212 to conduct. The output of the comparator 250 is also provided to a timer 258 whose clock begins at 15 a pulse width. A signal is provided on a second control line 254 to the switch control unit 256 to control the switch 212 to turn off when the timer is paused. Switch control unit 256 can include, for example, a set_reset latch and an interface circuit to drive the base of a bipolar transistor, and/or the gate of a MOS transistor. Preferably, the circuit also includes a R gate 260 and an input 262 from an overcurrent protection line 20. This can be produced by comparing a current sense input with a reference level defining a current limit threshold. When the overcurrent protection input 262 becomes active, the switch control unit 256 is immediately turned off by the control switch 212, so the implementation of the inter-period current limit control 3a and 3b shows the operation of the forward converter of the second diagram. 200807849 Example waveform. In these figures (and similar figures), waveform 300 indicates that the drive voltage turns on the base of a bipolar transistor switch, and waveform 3〇2 shows a collector current 'which is substantially equal to the transformer via forward converter 200 A current of one of the main windings 204 of 206. The main terminal current thus controls the amount of flux in the transformer 2〇6 and thus also the secondary side current. Waveform 304 shows a voltage at the collector extreme of the bipolar transistor switch. When the switch is turned on, the voltage equal to the voltage across the main winding 204 of transformer 2〇6 is reflected on the secondary winding 2〇8 of the transformer. When the switch is turned off, the current in the main terminal of the transformer drives one of the secondary ends, so the leveling capacitor 222 is charged via the rectifier 220; when the 10th opening is turned on, the main end of the forward converter stops driving the secondary side. Power is supplied from the leveling capacitor 222 to the output 218 (and the diode 220 is turned off). In the waveforms of the maps 3a and 3b, the scale of the waveform 300 is 500 mv for each portion, the waveform 302 is for each portion of the mA, and the waveform 304 is for each portion of 100 V. The driving waveform frequency in Fig. 3a is nearly 59 kHz; the driving waveform in Fig. 3b has a frequency of 5 4.8 ΚΗζ. The near observation of waveform 300 shows that the cutoff of the drive signal is not completely removed due to the characteristics of the bipolar switch; waveform 302 corresponds to 3〇4. In the preferred embodiment of the forward power converter, we describe After the transfer, the periodic transformer is reset (so it is not magnetized). During the reset period, the phase current flows into the main winding of the transformer in the opposite direction when the switch 212 (generally a power transistor) is turned on. The inductive resonance action of the transformer And the valley state 214 is used to perform the reset switch 212. Once turned off, there is a half-down wave in the chassis of the capacitor 214 (waveform 3〇4). The voltage on the chassis drives the power supply voltage by the action of the inductor. The top of the oscillometric voltage 27 200807849 of the transformer is mainly opposite to the direction of the forward energy transfer. (At this point a relatively high voltage is on the switch 212. The example waveform 304 of the 3a diagram is nearly 550V, which is much larger than the input voltage. And the switch is therefore able to withstand such a voltage without collapse.) When the capacitor discharges and the voltage on switch 212 returns to 0 5, the current in the transformer is mainly One of the source supply periods is reversed in the forward direction of the energy transfer portion, so the transformer is reset. If the switch is not turned on at this time, the resonance continues to decrease the formant string (see Figure 11 below). The ground switch 212 is turned on when the voltage on the switch is substantially small, that is, close to 0V (Fig. 3; Fig. 11). 10 Fig. 4 shows one of the discontinuous resonant forward converters for Fig. 2a. Equivalent circuit. This shows the bipolar transistor switch, the output rectifier, the parasitic capacitance (Cp) of the transformer, and the resonant capacitor (Cr), a magnetizing inductance (Lmag), which represents the energy stored in a transformer, and a leak. Inductance (Lleak), which represents the leakage inductance 15 between the primary and secondary windings of the transformer (from the leakage of some flux lines to the primary and secondary windings such that they act as an inductor). Usually, but not necessarily Cr is much larger than Cp. In operation, L mag keeps the main current flowing into C r to cause resonance, while the secondary current nearly matches the main current. The leakage inductance provides a current limit, which is especially helpful in leveling. When the container is in a short-circuit state, the overload at startup is reduced. 20 Figures 5a to 5d show an alternative topology of the resonant discontinuous forward converter. The resonant capacitor in Figure 5a is coupled to the switch (in this example) , shown as a bipolar transistor switch. The resonant capacitor in Figure 5b is at the output of the converter, more particularly the secondary winding connected to the transformer. Figure 5c clearly includes a series connection with the output rectifier. A small inductor. Figure 5d 28 200807849 shows a forward converter structure in which an automatic transformer is used. In an embodiment, the transformer is reset by the resonant portion of the transformer waveform: to discharge magnetization to resonance The transformer of the current in the capacitor is demagnetized and discharged resonantly. Alternatively or alternatively, the transformer can be reset by means of one of the couplings in series with a rectifier. Figure 6a shows an example of such a reset circuit in which one of the primary end auxiliary windings has a relative or opposite polarity to the primary and secondary windings of the transformer. During the off-period of the switch, a diode in series with the auxiliary winding becomes forward biased and conducts power back to the DC input (making the technique non-dispersive). The still and 6〇10 diagrams show alternative combinations in which the auxiliary winding is placed on the secondary side of the transformer and (again) has one polarity opposite the primary and secondary windings (the secondary side is connected to the diode) To the opposite side of the winding). In these examples, the auxiliary winding is connected in series with a rectifier and across the secondary winding and rectifier, and selectively connects the inductor to the output of the forward converter. 15 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ If there is sufficient delay, further resonance can finally be seen in waveform 3〇4, but it should be understood that the switch may be quadruple again by mi ^' so the control of the switch can be detected by the waveform 30 - substantially zero The voltage level and after its resonant half period, then wait - delay (which can be zero) before turning the switch on. The tolerance of this circuit operation is based on zero-voltage or resonant wave valleys, allowing __ (more specifically, switching off) to be long enough to cope with the resonance solution range and the resonant component value. 29 200807849 We next consider the start of the forward converter. The power supply output appears to be shorted at startup. Unlike a continuous forward converter, which uses a flyback diode' based on the load appearing on the RDFC, the insufficient amount of energy can be transferred to the converter's wheel to charge the output capacitor. This is especially a problem with the current 5 limit because ultra-high currents can occur at the main end of the transformer, while current limiting allows the switch to turn off the drive signal, allowing the output capacitor to be charged with a specific load. Figure 7a shows the difficulty of not being able to rise to the correct value during startup of the power supply output (voltage) by current limiting. The view of the collector voltage waveform 1 〇 also clearly shows that when the start-stop (because the secondary output is retroreflected) has a non-destructive component, and this non-zero collector voltage can be sensed to identify this start condition, as well as current limit , overload, and short circuit, if desired, in a preferred embodiment of the discontinuous resonant forward converter, the forward converter is controlled to operate in the frequency mode when activated, such as to operate 5 or 1G times the rate of positive b. This II can be implemented by selecting at the start-up - a simple vibrator that senses the collector voltage and is used to control the switch conductance to the higher-frequency board type. By - increasing the frequency of operation · c will increase the transfer output ^ * while still tilting the power supply. Figure IF (4) This increase operation (time division is shorter than the first _ Bay rate θ f), and can be found at this high frequency. (4) The time for bribery is (4) Change to the output voltage of normal operation. The system then describes the current limit for the discontinuous resonance forward transition 11, which operates in a resonant mode RDFC once it is activated and reaches steady state operation 30 200807849, with the accompanying input (voltage) - Output (electric castle). However, if a = planting is applied, especially (d) at a fixed frequency, the output current and switching current will increase significantly and the circuit may be damaged. Therefore, it is desirable to sense the switching current in the RDFC and the controller that we have described, which can shorten the drive current to control the drive current under an overload condition. The _display-RDFC-embodiment includes a controller having a current sense terminal (8) and a collector voltage (Sc) and a DC input voltage (sdc) sense input. Figure 8b shows the waveform of the forward converter during the load period, in which it can be found that the collector voltage waveform is no longer 由于 due to the output circuit load) correctly resonating (the first part of the half period is truncated). For comparison, the & graph shows one of the forward converters under no load conditions. We have previously explained how to implement overcurrent protection. In some cases, however, the next fixed current limit converter reduces the power transferred to the output, which in turn reduces the output voltage and increases the output current, which causes the converter output 15 voltage to drop significantly, even when the load is removed. In this case, the forward converter may not be able to recover. Strategies to address this or more issues can be applied. For example, the increased frequency restart technique can be used to effectively return the output voltage to its normal operating level as previously described. Alternatively or alternatively, an output inductor can be used, and/or the transformer's vapor inductance can be controlled to provide a current limiting effect. Again, the current limit can be varied to increase the current limit as the pulse width decreases. The latter approach will be explained in more detail later. More than 5 sheep, in some applications, such as a certain current load, the output voltage can enter a state of continuous decline, and the power supply in this state is not 31 200807849 In this way, in the same way as before, this is added during startup. The power to the load can be increased, thus increasing the turn-off voltage. : ', the shank can also limit the current at the same time to reduce the round-out or - series inductance can also be used to discard a part of the output of the electric power. This power is only 10 pulse 2-way converter when operating in a current limiting mode It is possible to adjust the wheel current by increasing the allowable switching current with the decrease. This I is safely implemented in the -RDFC type we have described, as the risk of injury conversion decreases with pulse width. Combined with this technology and the leakage inductance of the transformer and / or - series output inductance can make the output current with the output voltage = is pulled. Therefore, in general, the efficacy of this technique is to increase the pulse visibility to cause a reduced current limit. We now move forward to a technique that can be used to compensate for the use of components that have a relatively wide tolerance. It is very difficult to manufacture a 15 - transformer with a small tolerance for the main magnetizing inductance. One of these technologies removes and clings to the core, but this technique is expensive. A small tolerance resonant capacitor is also expensive. We have described how a fixed frequency vibrator in the controller can be used with the appropriate duty cycle selection to compensate for the increased tolerance in these components. Another technique involves compensating for increased tolerance by controlling the switch to be turned "on" during the zero (20) voltage phase of the primary (voltage) waveform. As mentioned above, there is a final time limit when the switching voltage is near zero volts (in reality, the voltage can be slightly lower than the ground potential). In the Zero Voltage Switching (ZFS) embodiment of the controller, the power switch is turned "on" during this time. The first to the present diagram shows the example clocks of different switch drive related collector voltage waveforms. 32 200807849 Referring to Figure 9a, this shows an example, but the open _ ideal state is turned on late. "This is better to switch, turn on, as shown in Figure 9b, which can cause too early loss of non-7 switch and electromagnetic interference. The first figure shows the second: 'The preferred clock that causes the switching voltage waveform. Sample_There is a set of poles perfect 10 15 20 The first reading (10) pulse is achieved by the next money line (four): In the collector pole μ material (four) and let the switch respond to this and lead to the pole power to zero , or after the voltage reaches zero _ small segment _, ^ = collector voltage starts to climb again. The clock of the 9th figure shows _ "the clock of the resonance switch, its switch as long as the collector power _ reaches zero, then we Next, we discuss the regulation of the output voltage of an RDFC. The effect is very poor, and it is relatively high in the inductance and the resistance of the component (winding). This result is the output of the electric power. - RDFC may have difficulty in compensating for input voltage variations, and usually the output voltage is chasing the input voltage. This is a problem in the forward converter that flows out of the grid-like total power supply because of the total voltage. Will vary greatly from time to time. However, the aforementioned controller implementation is suitable for pulse width and pulse wave frequency. Rate Control = Compliance to adjust the -RDFC output voltage. More specifically, the adjustment can be improved in the case of low wheeling or A-load conditions - or by increasing the pulse width and increasing the frequency of the field. Figure l〇a shows another - Can be used for output voltage regulation technology. In this configuration, '-input voltage transfer ·, whether it is - AC transfer or - DC transfer ^ conversion $, to provide _ DC input power supply to the forward direction, and It is fed back from the secondary side of the forward converter. To regulate the output 33 200807849 voltage, the wheel-in converter can include a - boost or buck or PFC (power factor correction) stage. Figure 10b shows the - multiphase Two power transformers are used in the assembly to improve the wheel-out adjustment. In the configuration of the i-th diagram, the switches are controlled so that the 5 switches are driven only when the other switches are off, creating complementary but non-overlapping drive waveforms. This technique is useful for small forward converters that operate at relatively high frequencies and are poorly regulated. Referring to Figure 11, we now describe some techniques for implementing low load and/or standby mode operation of an rdfc. In a preferred embodiment, I use pulse-hopping technology. A RDFC power supply operating at maximum frequency is traditionally inefficient at low loads and has high standby power loss. Therefore, when the load on an rdfc is reduced, the efficiency is reduced, especially in The performance is low at no load. This is mainly caused by high switching loss and high magnetizing current, etc. However, by controlling 15 turn-on and turn-off time, power loss can be reduced, especially by using the aforementioned PWM and PFM techniques, or In addition, the pulse of one cycle is jumped to a cycle equal to many times. It is also better to control the clock of these pulse waves to synchronize with the valleys in the resonance waveform, so that the RDFC switch after the trough resonance 0 is therefore in our system. In practice, we reduce the width of the pulse by limiting the switch before defining a shorter pulse, which reduces the load power loss. Additionally or alternatively, we cite a delay for the next pulse to make the switch turn on more slowly, skipping one or more switches to drive the pulse. This is also illustrated in Figure 11 where the drive pulse is delayed to skip one or more resonances. 34 200807849 Cycles As indicated by the switch (collector) voltage in the legend. When turned on, the zero-volt switch (collector) current has a sharp point in the zero-volt switch (collector) of the resonant switch waveform, and the eleventh figure also switches between the non-resonant valleys, wherein the switch is V-passed at the valley point of the resonant waveform to reduce the loss. . These techniques may be implemented to control 5 as in one of the foregoing: by a sensing configuration as shown in Figure 8a, or alternatively using voltage sensing as shown in Figure 12, for example, using Figure 2b. One of the control configurations. A reduced power mode, such as a pulse width modulation (decrease) or pulse skip mode, can be triggered by an event, such as - or more controller (wafer) power supply drops below a predetermined value; After the second resonance (see _) 10, or after a predetermined time (between the drive pulses). One of the pulse skipping techniques in the RDFC, such as the aforementioned, increases efficiency and reduces power loss at low loads or during standby. Pulse skipping technology also responds quickly at low loads. In yet another technique, the system practice we use, particularly in package 15 with a (bipolar) transistor switch, is used to limit the switching current rather than operating the transistor in the -linear region. This prevents the switch from overheating. In practice, when the switch is cut off, the main terminal voltage on the switch has a sudden rise, which can be sensed and controlled. 4 The overshoot is limited by the conduction of the crystal. Thus, for example, the switch can be partially turned on during startup to compensate for and limit voltage overshoot. 20 We next describe some of the chopping removal techniques that apply to an off-line (plug-in) RDFC converter. Referring to Fig. 12, this shows how a total chopping voltage can be sensed in a resonant discontinuous forward converter. As can be seen, the input voltage chopping can be sensed from a number of points, including the input DC bus, collector voltage, a transformer winding voltage, and/or output voltage. a small amount in the embodiment 35 200807849
的總漣波電壓被饋進時脈控制電路來變化^^“、及/或pFM 仏號,進而即日守调整輸入漣波電壓而實施漣波去除。rdfc 之操作頻率遠高於50ΗΖ*60Ηζ總漣波,且因此時脈控制電 路可以類似於控制直流輸出電壓之方式追縱與補償線連波 5 效應。 大致說來,我們已說明了運用一控制器來分析一或更 多輸入以及判定一電源開關之導通和截止時間而提供一驅 動信號的共振不連續順向轉換器(僅管是在簡單系統中亦 可運用一實質固定頻率/工作週期驅動)。脈波寬度及/或頻 10率可依據共振電路調整,或利用輸入至控制器之感測信號 或藉由一自發振盪器來減輕共振構件之容受問題。較佳 地,為確保最大能量通過RDFC而不妥協於共振作用及增加 損失,ΕΜΙ控制器係組配來實施零(開關)電壓切換。較佳地 控制裔係組配來在檢測到一過電流條件時終止一導通脈 15波,以保護電路(開關)、及/或負載。較佳地RDFC之實施例 在啟動及/或電流限制期間運用一增加頻率來協助輸出電 壓上升。PWM和PFM技術可運來改良負載與線調節。 【圖式簡單說明】 第1圖顯示習知之一順向轉換器範例。 20 第厶和沘圖分別顯示一不連續共振順向轉換器之實施 例,以及第2a圖之轉換器之一範例時脈與控制配置; 第3a和3b圖顯示第2a圖之順向轉換器自一17〇v直流輸 入供應提供分別為1A和2A之輸出電流操作期間的之範例 波形; 36 200807849 第4圖顯示依據本發明之一實施例之一順向轉換器電 源供應之一等效電路模型; 第5a-5d圖顯示依據本發明之一實施例之一順向轉換 器之另類拓樸; 5 第6a-6c圖顯示依據本發明之一實施例之利用一輔助 繞組來重設一順向轉換器之一變壓器之例子。 第7a和7b圖分別顯示一順向轉換器在啟動期間不具有 和具有南頻控制之波形, 第8a-8c圖分別顯示依據牟發明之一不連續共振順向 10 轉換器實施例的輸入感測連接組態以及在過負載與無負載 條件下之一順向轉換器; 第9a-9c圖分別顯示一順向轉換器之遲、早、及目標波 形時脈的範例; 第10a和10b圖分別顯示利用次級端回授之一順向轉換 15 器與一多相順向轉換器電路之調節; 第11圖顯示共振不連續順向轉換器之波形,其運用脈 波跳過與共振波谷切換例說一開關驅動脈波、一開關(集極) 電流、及一開關(集極)電壓之範例波形;而 第12圖顯示示範性的一共振不連續順向轉換器之電壓 20 感測電路技術,特別是漣波減少。 【主要元件符號說明】 101直流輸入 109主要繞組 102直流輸入 110變壓器 105開關裝置 111次級繞組 37 200807849 113 電容器 212 電源開關 114 整流器 214 共振電容器 115 二極體 216 整平電容器 117 輸出塞 218 直流輸出端 119 整平電容器 220 整流器 121 直流輸出 222 整平電容器 122 直流輸出 250 比較器 200 不連續共振順向轉換器 252 控制信號 202 直流輸入 254 第二控制線 204 主要繞組 256 開關控制單元 206 變壓器 258 計時器 208 次級繞組 260 OR閘 210 控制系統 262 輸入 210a 時脈控制模組 300 波形 210b 開關控制模組 302 波形 210c 開關導通與開關截止信 304 波形 號 38The total chopping voltage is fed into the clock control circuit to change the ^^", and / or pFM apostrophes, and then the chopping is performed by adjusting the input chopping voltage. The operating frequency of rdfc is much higher than 50ΗΖ*60Ηζ Chopping, and thus the clock control circuit can track the compensating line wave 5 effect in a manner similar to controlling the DC output voltage. Roughly speaking, we have illustrated the use of a controller to analyze one or more inputs and determine one A resonant discontinuous forward converter that provides a drive signal for the turn-on and turn-off times of the power switch (only a simple fixed frequency/duty cycle drive can be used in a simple system). Pulse width and/or frequency 10 rate It can be adjusted according to the resonance circuit, or the sensing signal input to the controller or by a spontaneous oscillator can be used to alleviate the problem of the resonance member. Preferably, the maximum energy is passed through the RDFC without compromising the resonance effect and increasing Loss, the controller is configured to implement zero (switching) voltage switching. Preferably, the control system is configured to terminate a 15 pulse of a conducting pulse when an overcurrent condition is detected. The protection circuit (switch), and/or the load. Preferably, the RDFC embodiment uses an increased frequency to assist in the rise of the output voltage during startup and/or current limiting. PWM and PFM techniques can be employed to improve load and line regulation. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows an example of a conventional forward converter. 20 The first and second figures show an embodiment of a discontinuous resonant forward converter, respectively, and an example of a converter of Figure 2a. Pulse and control configuration; Figures 3a and 3b show the example waveform of the forward converter of Figure 2a from a 17 〇v DC input supply during the output current operation of 1A and 2A respectively; 36 200807849 Figure 4 shows the basis One of the embodiments of the present invention is an equivalent circuit model of a forward converter power supply; Figures 5a-5d show an alternative topology of a forward converter in accordance with an embodiment of the present invention; 5 6a-6c The figure shows an example of resetting a transformer of a forward converter using an auxiliary winding according to an embodiment of the invention. Figures 7a and 7b respectively show that a forward converter does not have and has a south frequency control during startup. Waveforms, Figures 8a-8c show the input sense connection configuration of one embodiment of the discontinuous resonance forward 10 converter according to the invention and one of the forward converters under overload and no load conditions; 9a- Figure 9c shows an example of the late, early, and target waveform clocks of a forward converter; Figures 10a and 10b show one of the forward conversion 15 and the multiphase forward converter, respectively, using the secondary side feedback. Circuit adjustment; Figure 11 shows the waveform of the resonant discontinuous forward converter, which uses pulse skip and resonant valley switching to illustrate a switch drive pulse, a switch (collector) current, and a switch (collector Example waveform of voltage; and Fig. 12 shows an exemplary voltage sensing circuit technique of a resonant discontinuous forward converter, especially chopping reduction. [Main component symbol description] 101 DC input 109 main winding 102 DC input 110 transformer 105 switching device 111 secondary winding 37 200807849 113 capacitor 212 power switch 114 rectifier 214 resonant capacitor 115 diode 216 leveling capacitor 117 output plug 218 DC output Terminal 119 Leveling capacitor 220 Rectifier 121 DC output 222 Leveling capacitor 122 DC output 250 Comparator 200 Discontinuous resonance forward converter 252 Control signal 202 DC input 254 Second control line 204 Main winding 256 Switch control unit 206 Transformer 258 Timing 208 secondary winding 260 OR gate 210 control system 262 input 210a clock control module 300 waveform 210b switch control module 302 waveform 210c switch conduction and switch cutoff signal 304 waveform number 38