:BQ2053 九、發明說明： 【發明所屬之技術領域】 本發明係有關於一種功率晶體MOS的驅動方法及其電 路，尤指一種功率晶體MOS的驅動電路可運用各種切換電 路（如切換式電源供應器、轉換器等），解決習用功率晶體 MOS在切換損失或增加雜訊之相互依存的問題。 【先前技術】 關於線性電源供應器早在電子技術剛開始的時代即已 廣範地使用，這種型式的電源供應器之製作，不管其構件係 使用真空管或半導體，基本上結構都是相同的。 第1圖中顯示上述簡單的線性穩壓電源供應器之方塊 圖，其中該電源供應器可使用在低頻50hz或60hz之變壓 器，主要功能係將交流輸入電壓予以降低至低電壓之範圍， 當然其頻率還是保持與原來相同。再者，較低的二次側電壓 經由整流濾波之後，可以得到一直流的電壓，接著，此電壓 會饋入串聯通過（s e r i e s - p a s s)的主動元件中。此時在輸出端 所產生的輸出電壓會被取樣，並與固定的參考電壓做比較， 接者，串聯通過的主動元件如一可變電阻一般，可將輸出的 電壓控制並達到穩壓的目的，然而此種結構的操作方式，大 部份的能量損耗都以熱的形式散逸，因此，電源供應器的效 率會隨之降低至40%〜50%左右。 雖然此種線性電源供應器通常具有非常好的穩壓率、低 的輸出雜訊與漣波，不過仍有一些缺失，例如因爲較低的效 率，必須使用到面積較大且熱傳係數高的價昂散熱片及冷卻 ；1302053 用風扇；再者，爲了將交流輸入電壓降下來’另需配置較大 又笨重的功率隔離變壓裝置；另外’隨著高階電腦技術的快 速發展，電源供應器所能提供的單位體積功率密度的需求也 越來越高，相對也需要更高的效率。因此，爲符合上述需求， 應用在高頻操作下的切換式電源供應器’目前幾乎完全取代 了傳統的線性電源供應器。目前高頻切換式電源供應器規格 通常在20kHz以上，甚至可高達MHz(百萬）級的頻率範圍。 於第1圖中，高頻切換式電源供應器所使用之轉換元 件，係常用一種金屬氧化物半導體場效電晶體（Metal Oxide Semiconductor Field Effect Transistor MOSFET，以下簡稱 爲MOS)，原因在於MOS元件可於100kHz〜1MHz以上工作， 且此種轉換元件具有高速度、高功率、高電壓與高增益，且 幾乎沒有儲存時間等優點。 參閱第2圖式，當開啓MOS 200時，一般MOS驅動電 路係將輸入信號的驅動能力加以放大，並搭配一串聯電阻R 對MOS 200的輸入電容C充電，以達到導通MOS 200的需 求；當關閉MOS 200時，原先儲存在MOS 200輸入電容C 的能量，經由此電阻R，可被驅動電路所吸收。 然而，這類以MO S爲轉換電路元件之驅動電路，其最 大的缺點在於產生雜訊大小和驅動電路切換速度，這兩者之 間係具有依存性的關係，亦即，當提高切換頻率時，高頻化 會產生較高的切換損失及切換雜訊干擾，而造成轉換效率無 法有效地提升；但當降低切換頻率時，卻會造成線路尺寸無 法降低而無法符合高階電腦技術得需要。因此，如何在提 :1302053 高切換頻率之時，又能減少切換損失及抑制雜訊干擾， 成爲高頻MOS的驅動電路技術與硏究的重大課題。 【發明內容】 本發明針對電子產品薄輕化之需求，對於一般常以 爲切換元件之切換式電源轉換器（converter)或換 (inventer)，爲達到高頻切換而開啓/關閉M0S時，會導 高頻切換電源轉換器損失的現象，包括導通損失、切換 以及週邊控制電路之等損耗，而提供具體之解決辦法 置。 本發明的主要目的在於提供一種功率晶體Μ Ο S的 方法，用以在 M0S在快速導通初期時，使其動作在飽禾丨 三極體區兩段式斜率，以控制導通電流斜率、降低雜訊 解決先前功率晶體M0S驅動電路於產生雜訊大小和驅 路的切換速度兩者間依存性的問題。 本發明的另一目的是在提供一種功率晶體M0S的 電路，用以一 RC高通濾波器充、放電之動作所使M0S 動信號波形處於兩段式的工作區。 根據本發明之上述目的，功率晶體Μ 0 S的驅動方 係採用其在原舊有高頻切換式電源供應器之驅動M0S 間之一 Μ 0 S驅動放大電路與所須一輸入電容中並聯一 塑造電路波形塑造電路，及利用單顆電晶體作爲所使用 換元件，其特徵在於：切換元件的電晶體初期導通時， 在飽和區（saturation)，並拉高其曲線之斜率，以因應供 流變化時，降低切換雜訊。 顯然 M0S 流器 致該 損失 與裝 驅動 ]區、 ，以 動電 驅動 的驅 法， 電路 波形 之切 操作 應電 ;1302053 根據本發明之上述目的，提出一種功率晶體M0S的驅 動電路’其在原舊有高頻切換式電源供應器之驅動M0S電 路間之一 MOS驅動放大電路與所須一輸入電容中並聯一波 形塑造電路，其中該波形塑造電路至少包含··一 RC高通濾 波器、以及一小信號MOS。該RC高通濾波器，爲一第一電 阻與一第一電容串聯所組成，其中該第一電阻之一端接地及 該第一電容之一端分別連接一電壓源與一第二電阻器。該小 信號MOS之閘極連接該RC高通濾波器之分壓點，及用以作 爲一切換元件。 【實施方式】 以下詳細地討論目前較佳的實施例。然而應被理解的 是’本發明提供許多可適用的發明觀念，而這些觀念能被體 現於很寬廣多樣的特定具體背景中。所討論的特定具體的實 施例僅是說明使用本發明的特定方式，而且不會限制本發明 的範圍。 一般習用MOS切換式電源轉換器在要求快速開啓/關閉 (turn on /off)狀態下，以便降低切換損失（switching loss)， 結果會導至雜訊（noise)增加，但若要降低雜訊，則要將驅動 電路速度放慢，但這樣又會導至切換損失增加。 再者，在一般驅動電路因快速導電晶體（transistor)所以 都會有最短時間上的要求，假若所需導通的時間少於最短時 間的要求，則驅動電路會呈不穩定的狀態。 根據前述所言及針對習用M0S驅動電路（請參閱第2圖） 之電路予以改良，本發明提供一種功率晶體M0S的驅動方 13,02053 s Ε 0在路 Μ:電 在於造 可在塑 ， 徵形 法特波 其該通 ，, 導 率路期 斜電初 流造體 電塑晶 通形電 導波當 其 一， 制聯件 控並元 ， 路換 期線切 初大爲 通放作 導動體 速驅晶 L、 一· 快 S ΐ 時，使將在飽和區（saturation)拉高該電晶體驅動信號曲線之 斜率，使供應電流變化之切換雜訊降低。 以下爲本發明之MOS的驅動方法搭配之一功率晶體 M0S的驅動電路，來解釋本發明所運用的工作原理。 如第3圖所示，在原舊有高頻切換式電源供應器之驅動 M0S電路間之一 M0S驅動放大電路與所須一輸入電容CG 中並聯一波形塑造電路3 00，其中該波形塑造電路300至少 包含：一 RC高通濾波器310及一小信號M0S 3 20 (以此實施 例中前述提及的電晶體以小信號M0S爲切換開關元件）。RC 高通濾波器310爲一第一電阻R!與一第一電容C!串聯所組 成，其中第一電阻R!之一端接地及第一電容C!之一端分別 連接一電壓源（Vin)與一第二電阻器R2，其用以輸出一電 壓，小信號M0S 320之閘極（Gate)與連接RC高通濾波器310 之分壓點，用以接收該RC高通濾波器3 1 0所輸出的電壓。 如第3圖所示，於此實施例中，當驅動電路信號由M0S 驅動放大線路送出後（Vin) ，RC高通濾波器310會產生一 個電壓（Vrc)，此電壓會使小信號M0S 3 20導通，而將原先 應供己輸入電容CG的電壓拉到〇V，且RC高通濾波器310 的波形會以常數R i C !的指數函數隨時間常數下降，其內部 靜態信號部分被濾掉，只留下動態信號，而時間常數是由第 一電阻R!和第一電容C!所産生的。此時，小信號M0S 320 ；1302053 慢慢關閉，從而使小信號M0S 3 20的汲極（drain)端電壓慢慢 上升，此電壓會反映在輸入電容CG端（Vo)，使實際的驅動 線路呈上升的斜率，一旦小信號MOS 3 2 0完全關閉後，整 體線路的動作就如傳統的驅動線路’可以較快斜率上升。 如第4圖所示，當小信號MO S導通時，會經過第一段 信號所主宰的飽和區（saturation)，因爲此區段的斜率較低 緩，所以可以使小信號MOS穩定的停留在飽和區，可應付 極小導通比（導通比；MOS在一個工作周期（duty cycle)內， 其導通時間所佔的百分比率）的狀態，並降低切換雜訊，而 當實際的導通比比前述飽和區的時間長時，該小信號MOS 動作進入第二段信號所主宰的三極體區（tri ode)，以極快的 斜率上升，使MOS完全導通（爲第3圖中，所繪製M0S等 效電路），可降低切換損失。 新的電路由於會短暫的停留在飽和區，所以會有較大的 損失，但因此時間是可以調整的，所以可以將導通損失抑制 在合理的範圍內，整體效率略差於當舊電路以極快速度上升 之效率，但遠優於當舊電路爲考慮雜訊而以較緩的斜率上升 時的效率。 由上述本發明較佳實施例可知，本發明的技術特點是利 用驅動電路之RC高通濾波器之充、放電之動作，使MOS 處於兩段式的工作區，一倂解決如：在一低導通比的狀態， MO S所帶來的頻率無法再加快的瓶頸，又如另一降低切換頻 率狀態下，會使線路的尺寸無法降低等相依存的問題。 【圖式簡單說明】 -10- :1302053 第1圖 繪示簡單的線性穩壓電源供應器之方塊圖。 第2圖 繪示習用MOS驅動電路示意圖。 第3圖 繪示本發明功率晶體MOS的驅動電路示意圖。 第4圖 繪示本發明功率晶體MOS的驅動電路之驅動 信號波形圖。 【主要元件符號說明】 200 : MOS，即金屬氧化物半導體場效電晶體 3 0 0 :波形塑造電路 3 10 : RC高通瀘波器 320 :小信號MOS R ·· 電阻 C : 輸入電容 Ri · 第一電阻 Ci ： 第一電容 CG ·· 輸入電容BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving method of a power crystal MOS and a circuit thereof, and more particularly to a driving circuit of a power crystal MOS capable of using various switching circuits (such as a switching power supply). , converters, etc.), to solve the problem of the conventional power crystal MOS in switching losses or increasing the interdependence of noise. [Prior Art] Linear power supplies have been widely used since the beginning of electronic technology. The manufacture of this type of power supply, regardless of the components used in vacuum tubes or semiconductors, basically has the same structure. . Figure 1 shows a block diagram of the above simple linear regulated power supply. The power supply can be used in a low-frequency 50hz or 60hz transformer. The main function is to reduce the AC input voltage to a low voltage range. The frequency remains the same as before. Furthermore, after the lower secondary voltage is rectified and filtered, a constant current voltage can be obtained, which is then fed into the active component in series (s e r i e s - p a s s). At this time, the output voltage generated at the output will be sampled and compared with a fixed reference voltage. The active component connected in series, such as a variable resistor, can control the output voltage and achieve the purpose of voltage regulation. However, in the operation of this structure, most of the energy loss is dissipated in the form of heat, so the efficiency of the power supply will be reduced to about 40% to 50%. Although such a linear power supply usually has very good regulation rate, low output noise and chopping, there are still some shortcomings, for example, because of lower efficiency, it is necessary to use a large area and a high heat transfer coefficient. The price of the heat sink and cooling; 1302053 with a fan; in addition, in order to reduce the AC input voltage, 'the need to configure a large and cumbersome power isolation transformer; in addition to the rapid development of high-end computer technology, power supply The demand for unit volume power density that can be provided is also increasing, and relatively higher efficiency is required. Therefore, in order to meet the above requirements, the switching power supply unit applied under high frequency operation has almost completely replaced the conventional linear power supply. Currently, high-frequency switching power supply specifications are usually above 20 kHz, and even up to the MHz (million) frequency range. In the first figure, the conversion element used in the high-frequency switching power supply is a metal oxide semiconductor field effect transistor (hereinafter referred to as MOS) because the MOS device can be used. It operates above 100 kHz to 1 MHz, and this conversion element has high speed, high power, high voltage and high gain, and has almost no storage time. Referring to FIG. 2, when the MOS 200 is turned on, the general MOS driving circuit amplifies the driving capability of the input signal, and charges the input capacitor C of the MOS 200 with a series resistor R to achieve the requirement of turning on the MOS 200; When the MOS 200 is turned off, the energy originally stored in the input capacitance C of the MOS 200 can be absorbed by the driving circuit via the resistor R. However, such a driving circuit using MO S as a switching circuit element has the greatest disadvantage in that it generates a noise level and a switching speed of the driving circuit, and the relationship between the two has a dependency relationship, that is, when the switching frequency is increased. High frequency will generate high switching loss and switch noise interference, which will not effectively improve the conversion efficiency. However, when the switching frequency is lowered, the line size cannot be reduced and it cannot meet the needs of high-end computer technology. Therefore, how to reduce the switching loss and suppress the noise interference when raising the high switching frequency of 1302053 becomes a major issue of the driving circuit technology and research of high frequency MOS. SUMMARY OF THE INVENTION The present invention is directed to the demand for thinning and lightening of electronic products. For a switching power converter or an inverter that is generally considered to be a switching element, when the MIMO is turned on/off to achieve high frequency switching, The phenomenon of high-frequency switching power converter loss, including conduction loss, switching, and peripheral control circuit losses, provides a specific solution. The main object of the present invention is to provide a power crystal Ο 的 S method for controlling the slope of the conduction current and reducing the impurity when the MOS is in the early stage of fast conduction, in the two-stage slope of the saturation region. The problem solves the problem of the dependence of the previous power crystal MOS drive circuit on the generation of the noise size and the switching speed of the drive. Another object of the present invention is to provide a power crystal MOS circuit for charging and discharging an RC high-pass filter to cause the MOS signal waveform to be in a two-stage operation area. According to the above object of the present invention, the driving mode of the power crystal Μ 0 S is formed by using a Μ 0 S driving amplifying circuit between the driving MOS of the old high-frequency switching power supply and the input capacitor. The circuit waveform shaping circuit and the use of a single transistor as the replacement component used are characterized in that: when the transistor of the switching element is initially turned on, in the saturation region, the slope of the curve is raised to respond to the change of the supply current. When switching, reduce the switching noise. Obviously, the M0S streamer causes the loss and the drive area, and the electrokinetic drive method, the circuit waveform is cut and operated; 1302053 According to the above object of the present invention, a drive circuit of the power crystal MOS is proposed. A MOS drive amplifying circuit between the driving MOS circuits of the high frequency switching power supply and a waveform shaping circuit connected in parallel with an input capacitor, wherein the waveform shaping circuit at least comprises an RC high pass filter and a small Signal MOS. The RC high-pass filter is composed of a first resistor connected in series with a first capacitor, wherein one end of the first resistor is grounded and one end of the first capacitor is connected to a voltage source and a second resistor, respectively. The gate of the small signal MOS is connected to the voltage dividing point of the RC high-pass filter and used as a switching element. [Embodiment] The presently preferred embodiment will be discussed in detail below. It should be understood, however, that the present invention provides a number of applicable inventive concepts which can be embodied in a wide variety of specific specific contexts. The specific embodiments discussed are merely illustrative of specific ways of using the invention and are not intended to limit the scope of the invention. Generally, the conventional MOS switching power converter requires a fast turn on/off state to reduce the switching loss, and the result is an increase in noise, but to reduce noise, The drive circuit speed is slowed down, but this leads to an increase in switching losses. Furthermore, in general drive circuits, there is a minimum time requirement due to a fast conductive transistor. If the required turn-on time is less than the minimum time requirement, the drive circuit will be unstable. According to the foregoing description, the circuit for the conventional MOS driving circuit (refer to FIG. 2) is improved, and the present invention provides a driving side of the power crystal MOS 13,02053 s Ε 0 in the path: the electric is in the plastic, the shape The French wave of the pass, the conductivity of the road, the electric current, the electric current, the electric current, the electric wave, the electric current, the electric current, the electric current, the electric current, the electric current, the electric current, the electric current, the electric current When the crystal L, a fast S ΐ is pulled, the slope of the transistor driving signal curve is pulled high in the saturation region, so that the switching noise of the supply current change is lowered. The following is a driving circuit of the MOS of the present invention, which is combined with a driving circuit of a power crystal MOS to explain the working principle of the present invention. As shown in FIG. 3, a waveform shaping circuit 300 is connected in parallel with a required input capacitance CG between one of the driving MOS circuits of the original high-frequency switching power supply, and the waveform shaping circuit 300. At least: an RC high-pass filter 310 and a small signal M0S 3 20 (the transistor mentioned in the foregoing embodiment uses the small signal M0S as the switching element). The RC high-pass filter 310 is composed of a first resistor R! and a first capacitor C!, wherein one end of the first resistor R! is grounded and one end of the first capacitor C! is connected to a voltage source (Vin) and a a second resistor R2 for outputting a voltage, a gate of the small signal MOS 320 and a voltage dividing point connected to the RC high-pass filter 310 for receiving the voltage output by the RC high-pass filter 3 1 0 . As shown in FIG. 3, in this embodiment, when the driving circuit signal is sent out by the MOS driving amplifier circuit (Vin), the RC high-pass filter 310 generates a voltage (Vrc) which causes the small signal M0S 3 20 Turning on, and pulling the voltage originally supplied to the input capacitor CG to 〇V, and the waveform of the RC high-pass filter 310 is decreased with the time constant by the exponential function of the constant R i C ! , and the internal static signal portion is filtered out. Only the dynamic signal is left, and the time constant is generated by the first resistor R! and the first capacitor C!. At this time, the small signal M0S 320 ; 1302053 is slowly turned off, so that the drain voltage of the small signal M0S 3 20 is slowly increased, and this voltage is reflected in the input capacitor CG terminal (Vo), so that the actual driving circuit With a rising slope, once the small signal MOS 3 2 0 is completely turned off, the overall line action can be as fast as the conventional drive line'. As shown in Figure 4, when the small signal MO S is turned on, it will pass through the saturation of the first segment of the signal. Because the slope of this segment is relatively slow, the small signal MOS can be stably stayed at The saturation region can cope with the state of minimum conduction ratio (conduction ratio; MOS in a duty cycle, the percentage of its on-time), and reduce switching noise, while the actual conduction ratio is lower than the aforementioned saturation region For a long time, the small signal MOS action enters the triode of the second segment of the signal, and rises with a very fast slope to make the MOS fully conductive (for the M0S equivalent in Figure 3) Circuit) to reduce switching losses. The new circuit will have a large loss because it will stay in the saturation zone for a short time, but the time can be adjusted, so the conduction loss can be suppressed within a reasonable range, and the overall efficiency is slightly worse than that of the old circuit. The efficiency of rapid rise, but much better than when the old circuit rises with a gentle slope in consideration of noise. According to the preferred embodiment of the present invention, the technical feature of the present invention is that the charging and discharging operations of the RC high-pass filter of the driving circuit are used to make the MOS in a two-stage working area, such as: a low conduction. The ratio of the state, the frequency of the MO S can no longer accelerate the bottleneck, and another way to reduce the size of the line, the size of the line can not be reduced and so on. [Simple description of the diagram] -10-:1302053 Figure 1 shows a block diagram of a simple linear regulated power supply. Figure 2 shows a schematic diagram of a conventional MOS drive circuit. FIG. 3 is a schematic diagram showing a driving circuit of the power crystal MOS of the present invention. Fig. 4 is a view showing a waveform of a driving signal of a driving circuit of the power crystal MOS of the present invention. [Main component symbol description] 200 : MOS, metal oxide semiconductor field effect transistor 3 0 0 : waveform shaping circuit 3 10 : RC high-pass chopper 320 : small signal MOS R · · resistance C : input capacitance Ri · a resistor Ci: a first capacitor CG ·· an input capacitor