TWI435518B - Power control circuit - Google Patents
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Description
本發明係關於一種電源控制電路,特別關於一種具脈寬調變之電源控制電路。The present invention relates to a power supply control circuit, and more particularly to a power supply control circuit with pulse width modulation.
脈寬調變(Pulse Width Modulation,PWM)為切換模式電源供應電路中的一種傳統技術,其方法為控制切換元件的導通時間以達到所需之負載需求。Pulse Width Modulation (PWM) is a conventional technique in switching mode power supply circuits by controlling the on-time of the switching elements to achieve the required load requirements.
請參照圖1所示,其為習知一種電源控制電路1的功能方塊圖。電源控制電路1具有一電源單元11、一轉換單元12、一電壓回授單元13及一控制單元14。電源單元11係輸出一電源訊號PS。轉換單元12係依據電源訊號PS輸出一驅動訊號DS,以驅動一負載裝置L。電壓回授單元13係依據驅動訊號DS的變化(即負載裝置L的負載變化)輸出回授訊號VC 以輸入控制單元14。而控制單元14係依據回授訊號VC 輸出一控制訊號CS,以控制轉換單元12之一切換開關(圖未顯示)導通或截止。其中,控制訊號CS可控制切換開關之責任週期(即控制導通時間)。藉由切換開關之不同責任週期的導通,可使轉換單元12產生之驅動訊號DS與負載裝置L達到平衡。Please refer to FIG. 1 , which is a functional block diagram of a conventional power supply control circuit 1 . The power control circuit 1 has a power supply unit 11, a conversion unit 12, a voltage feedback unit 13, and a control unit 14. The power supply unit 11 outputs a power signal PS. The converting unit 12 outputs a driving signal DS according to the power signal PS to drive a load device L. The voltage feedback unit 13 outputs the feedback signal V C to the control unit 14 according to the change of the driving signal DS (ie, the load change of the load device L). The control unit 14 outputs a control signal CS according to the feedback signal V C to control whether one of the switching switches (not shown) of the conversion unit 12 is turned on or off. The control signal CS can control the duty cycle of the switch (ie, control the on time). The driving signal DS generated by the converting unit 12 can be balanced with the load device L by the conduction of the different duty cycles of the switching switch.
例如,當負載裝置L為輕負載時,驅動訊號DS的電壓值將上升,電壓回授單元13感測驅動訊號DS的變化並輸出回授訊號VC ,以輸入控制單元14。控制單元14依據回授訊號VC 輸出控制訊號CS降低切換開關之責任週期(即降低切換訊號的導通時間),以減少轉換單元12的輸出功率,進而減少電源單元11之輸出功率而與負載裝置L達到平衡。For example, when the load device L is lightly loaded, the voltage value of the driving signal DS will rise, and the voltage feedback unit 13 senses the change of the driving signal DS and outputs the feedback signal V C to be input to the control unit 14. The control unit 14 outputs the control signal CS according to the feedback signal V C to reduce the duty cycle of the switch (ie, reduce the on-time of the switching signal) to reduce the output power of the conversion unit 12, thereby reducing the output power of the power unit 11 and the load device. L reaches equilibrium.
然而,上述之脈寬調變技術中,不論電源單元11輸出的電壓值有任何變化,控制單元14輸出之控制訊號CS控制轉換單元12之切換開關導通與截止的切換頻率卻是固定不變的。另外,為了減少電源控制電路1的元件體積及降低電路成本,切換開關的切換頻率均設計得相當高(例如可達1百萬赫兹),因此,將造成轉換單元12的切換損失也相當大,進而造成電源控制電路1的效率降低。However, in the pulse width modulation technique described above, regardless of any change in the voltage value outputted by the power supply unit 11, the switching frequency of the switching control of the switching signal controlled by the control unit 14 controlled by the control unit 14 is fixed. . In addition, in order to reduce the component volume of the power control circuit 1 and reduce the circuit cost, the switching frequency of the switching switch is designed to be relatively high (for example, up to 1 megahertz), and therefore, the switching loss of the switching unit 12 is also considerable. This in turn causes the efficiency of the power supply control circuit 1 to decrease.
因此,如何提供一種電源控制電路,可依據輸入電壓調整切換頻率,以降低切換損失,進而可提高電源控制電路的效率,已成為重要課題之一。Therefore, how to provide a power control circuit, which can adjust the switching frequency according to the input voltage to reduce the switching loss, thereby improving the efficiency of the power control circuit has become one of the important topics.
有鑑於上述課題,本發明之目的為提供一種可依據輸入電壓調整切換頻率,以降低切換損失,進而可提高效率之電源控制電路。In view of the above problems, an object of the present invention is to provide a power supply control circuit that can adjust a switching frequency according to an input voltage to reduce switching loss and thereby improve efficiency.
為達上述目的,依據本發明之電源控制電路包括一電源單元、一轉換單元、一控制單元以及一頻率線性調整單元。電源單元係輸出一電源訊號。轉換單元係與電源單元電性連接,並依據電源訊號產生一驅動訊號。控制單元係與轉換單元電性連接,並產生一控制訊號以控制轉換單元,控制單元具有一頻率調整電容。頻率線性調整單元係與電源單元及頻率調整電容電性連接,並依據電源訊號產生一頻率調整訊號,頻率調整訊號輸入頻率調整電容的第一端以降低頻率調整電容的充電電流,進而使控制訊號降低轉換單元之切換頻率。To achieve the above object, a power supply control circuit according to the present invention includes a power supply unit, a conversion unit, a control unit, and a frequency linear adjustment unit. The power unit outputs a power signal. The conversion unit is electrically connected to the power supply unit and generates a driving signal according to the power signal. The control unit is electrically connected to the conversion unit and generates a control signal to control the conversion unit. The control unit has a frequency adjustment capacitor. The frequency linear adjustment unit is electrically connected to the power supply unit and the frequency adjustment capacitor, and generates a frequency adjustment signal according to the power signal, and the frequency adjustment signal input frequency adjusts the first end of the capacitor to reduce the charging current of the frequency adjustment capacitor, thereby making the control signal Reduce the switching frequency of the conversion unit.
在本發明之一實施例中,轉換單元係為返馳式轉換器、或順向式轉換器、或升壓式轉換器、或降壓式轉換器、或升/降壓式轉換器、或邱克(Cuk)轉換器、或Sepic轉換器、或Zeta轉換器、或推挽式轉換器、或全橋式轉換器、或半橋式轉換器。In an embodiment of the invention, the conversion unit is a flyback converter, or a forward converter, or a boost converter, or a buck converter, or a step-up/down converter, or A Cuk converter, or a Sepic converter, or a Zeta converter, or a push-pull converter, or a full bridge converter, or a half bridge converter.
在本發明之一實施例中,轉換單元具有至少一切換元件,控制訊號係藉由降低切換元件之切換頻率,進而降低轉換單元之切換頻率。In an embodiment of the invention, the conversion unit has at least one switching element, and the control signal reduces the switching frequency of the conversion unit by reducing the switching frequency of the switching element.
在本發明之一實施例中,控制單元更具有一控制器,頻率調整訊號降低頻率調整電容之充電電流,進而降低控制器之振盪頻率。In an embodiment of the invention, the control unit further has a controller, and the frequency adjustment signal reduces the charging current of the frequency adjustment capacitor, thereby reducing the oscillation frequency of the controller.
在本發明之一實施例中,頻率線性調整單元具有一第一電阻及一第二電阻,第一電阻的第一端電性連接電源單元的輸出端,第一電阻的第二端與第二電阻的第一端電性連接,第二電阻的第二端係接地。In an embodiment of the invention, the frequency linear adjustment unit has a first resistor and a second resistor. The first end of the first resistor is electrically connected to the output end of the power unit, and the second end and the second end of the first resistor The first end of the resistor is electrically connected, and the second end of the second resistor is grounded.
在本發明之一實施例中,頻率線性調整單元更具有一開關元件,開關元件的第一端係電性連接第一電阻的第二端,開關元件的第二端係電性連接頻率調整電容之第一端,開關元件的第三端係電性接地。In an embodiment of the invention, the frequency linear adjustment unit further has a switching element, the first end of the switching element is electrically connected to the second end of the first resistor, and the second end of the switching element is electrically connected to the frequency adjusting capacitor At the first end, the third end of the switching element is electrically grounded.
在本發明之一實施例中,切換元件及開關元件係包含雙載子接面電晶體,或場效電晶體、或金屬氧化物半導體場效電晶體。In an embodiment of the invention, the switching element and the switching element comprise a bipolar junction transistor, or a field effect transistor, or a metal oxide semiconductor field effect transistor.
在本發明之一實施例中,電源控制電路更包括一電壓回授單元,其係與轉換單元及控制單元電性連接,並依據驅動訊號產生一電壓回授訊號。In an embodiment of the invention, the power control circuit further includes a voltage feedback unit electrically connected to the conversion unit and the control unit, and generating a voltage feedback signal according to the driving signal.
在本發明之一實施例中,電壓回授單元將驅動訊號之電壓轉換,並輸出電壓回授訊號,以使控制訊號改變切換元件的責任週期。In an embodiment of the invention, the voltage feedback unit converts the voltage of the driving signal and outputs a voltage feedback signal, so that the control signal changes the duty cycle of the switching element.
在本發明之一實施例中,控制單元係依據電壓回授訊號及頻率調整訊號輸出控制訊號。In an embodiment of the invention, the control unit outputs the control signal according to the voltage feedback signal and the frequency adjustment signal.
在本發明之一實施例中,電源控制電路更包括一電流回授單元,其係與轉換單元及控制單元電性連接,電流回授單元係依據轉換單元輸出一電流回授訊號,以輸入控制單元。In an embodiment of the invention, the power control circuit further includes a current feedback unit electrically connected to the conversion unit and the control unit, and the current feedback unit outputs a current feedback signal according to the conversion unit for input control. unit.
在本發明之一實施例中,控制單元係依據頻率調整訊號、電壓回授訊號及電流回授訊號產生控制訊號,以控制切換元件。In an embodiment of the invention, the control unit generates a control signal according to the frequency adjustment signal, the voltage feedback signal, and the current feedback signal to control the switching element.
在本發明之一實施例中,電源訊號之電壓值越高時,控制單元依據頻率調整訊號使頻率調整電容的充電電流越小,進而使控制訊號控制切換元件之切換頻率降低越多。In an embodiment of the invention, when the voltage value of the power signal is higher, the control unit adjusts the frequency of the frequency adjustment capacitor according to the frequency adjustment signal, thereby reducing the switching frequency of the control signal switching component.
承上所述,因依據本發明之電源控制電路的頻率線性調整單元係依據電源單元輸出之電源訊號產生一頻率調整訊號,而頻率調整訊號係輸入控制單元之頻率調整電容的第一端。藉此,可依據電源單元輸出之電源訊號的電壓準位降低控制單元之頻率調整電容的充電電流,進而增加頻率調整電容的充電時間,使控制單元內之控制IC的振盪頻率降低,進而降低轉換單元之切換元件的切換損失。與習知相較,本發明之電源控制電路可依據輸入電壓調整(降低)轉換單元之切換元件的切換頻率,故可減少切換元件切換時之暫態損失,進而可提高電源控制電路的效率。According to the above, the frequency linear adjustment unit of the power control circuit according to the present invention generates a frequency adjustment signal according to the power signal outputted by the power unit, and the frequency adjustment signal is input to the first end of the frequency adjustment capacitor of the control unit. Therefore, the charging current of the frequency adjustment capacitor of the control unit can be reduced according to the voltage level of the power signal output by the power unit, thereby increasing the charging time of the frequency adjusting capacitor, thereby reducing the oscillation frequency of the control IC in the control unit, thereby reducing the conversion. Switching loss of the switching elements of the unit. Compared with the conventional one, the power control circuit of the present invention can adjust (lower) the switching frequency of the switching element of the conversion unit according to the input voltage, thereby reducing the transient loss when the switching element is switched, thereby improving the efficiency of the power control circuit.
以下將參照相關圖式,說明依本發明較佳實施例之一種電源控制電路,其中相同的元件將以相同的參照符號加以說明。DETAILED DESCRIPTION OF THE INVENTION A power supply control circuit in accordance with a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein like elements will be described with the same reference numerals.
請同時參照圖2A及圖2B所示,其分別為本發明第一實施例之一種電源控制電路2的功能方塊示意圖及電路示意圖。電源控制電路2為一電源供應器,並可依據不同的負載狀況供應電力給一負載裝置L使用。其中,負載裝置L例如可為一家電產品、手機、電腦、全球定位系統(global position system,GPS)、個人行動助理(personal digital assistant,PDA)或其它電子產品。於此,並不加以限制。Please refer to FIG. 2A and FIG. 2B simultaneously, which are respectively a functional block diagram and a circuit diagram of a power control circuit 2 according to the first embodiment of the present invention. The power control circuit 2 is a power supply and can supply power to a load device L according to different load conditions. The load device L can be, for example, an electric product, a mobile phone, a computer, a global position system (GPS), a personal digital assistant (PDA), or other electronic products. Here, there is no limitation.
電源控制電路2包括一電源單元21、一轉換單元22、一控制單元23、一頻率線性調整單元24以及一電壓回授單元25。The power control circuit 2 includes a power supply unit 21, a conversion unit 22, a control unit 23, a frequency linear adjustment unit 24, and a voltage feedback unit 25.
電源單元21係輸出一電源訊號PS。於此,電源訊號PS係為一直流電壓訊號。其中,電源訊號P可具有固定電壓準位或可變電壓準位。若為可變電壓準位,其電壓準位例如可於36伏特至75伏特之間變動。另外,若使用交流電源來驅動負載裝置L,則電源單元21內係包含有整流電路,使輸出之電源訊號PS為直流電壓訊號。The power unit 21 outputs a power signal PS. Here, the power signal PS is a DC voltage signal. The power signal P may have a fixed voltage level or a variable voltage level. If it is a variable voltage level, its voltage level can vary, for example, between 36 volts and 75 volts. Further, when the load device L is driven by the AC power source, the power supply unit 21 includes a rectifier circuit for causing the output power signal PS to be a DC voltage signal.
轉換單元22係與電源單元21電性連接,轉換單元22係依據電源訊號PS產生一驅動訊號DS,以供應負載裝置L所需的電力。其中,轉換單元22係為一直流轉直流轉換器(DC-DC Converter),並例如可為返馳式轉換器、或順向式轉換器、或升壓式轉換器、或降壓式轉換器、或升/降壓式轉換器、或邱克(Cuk)轉換器、或Sepic轉換器、或Zeta轉換器、或推挽式轉換器、或全橋式轉換器、或半橋式轉換器。在本實施例中,轉換單元22係以一返馳式轉換器為例。The converting unit 22 is electrically connected to the power unit 21, and the converting unit 22 generates a driving signal DS according to the power signal PS to supply the power required by the load device L. The conversion unit 22 is a DC-DC converter, and may be, for example, a flyback converter, a forward converter, or a boost converter, or a buck converter. Or a boost/buck converter, or a Cuk converter, or a Sepic converter, or a Zeta converter, or a push-pull converter, or a full bridge converter, or a half bridge converter. In this embodiment, the conversion unit 22 is exemplified by a flyback converter.
另外,轉換單元22具有至少一切換元件221,而控制單元23係與轉換單元22之切換元件221電性連接。本實施例係以一切換元件221為例來說明。其中,控制單元23係產生一控制訊號CS以控制轉換單元22之切換元件221作動。控制訊號CS係為一脈寬調變訊號,並可控制切換元件221的導通與截止,以使轉換單元22依據電源訊號PS輸出驅動訊號DS。In addition, the conversion unit 22 has at least one switching element 221, and the control unit 23 is electrically connected to the switching element 221 of the conversion unit 22. This embodiment is described by taking a switching element 221 as an example. The control unit 23 generates a control signal CS to control the switching element 221 of the conversion unit 22 to operate. The control signal CS is a pulse width modulation signal, and can control the on and off of the switching element 221, so that the conversion unit 22 outputs the driving signal DS according to the power signal PS.
電壓回授單元25係與轉換單元22及控制單元23電性連接。電壓回授單元25係依據驅動訊號DS輸出一電壓回授訊號VC 。在本實施例中,電壓回授單元25具有兩串聯的電阻R3、R4,使得電壓回授訊號VC 為驅動訊號DS的分壓。換言之,電壓回授單元25係將驅動訊號DS之電壓進行分壓轉換,以輸出電壓回授訊號VC ,使控制訊號CS可改變切換元件221切換時的責任週期。於此,電壓回授訊號VC 係等於R4×DS/(R3+R4)。The voltage feedback unit 25 is electrically connected to the conversion unit 22 and the control unit 23. The voltage feedback unit 25 outputs a voltage feedback signal V C according to the driving signal DS. In this embodiment, the voltage feedback unit 25 has two resistors R3 and R4 connected in series such that the voltage feedback signal V C is a divided voltage of the driving signal DS. In other words, the voltage feedback unit 25 divides and converts the voltage of the driving signal DS to output the voltage feedback signal V C , so that the control signal CS can change the duty cycle when the switching element 221 is switched. Here, the voltage feedback signal V C is equal to R4 × DS / (R3 + R4).
若驅動訊號DS因負載變輕而其電壓準位上升時,電壓回授訊號VC 的電壓準位亦相同比例上升。換言之,當驅動訊號DS之電壓值因負載裝置L的負載變小而上升時,電壓回授單元25可依據上升之驅動訊號DS的電壓準位輸出一電壓回授訊號VC ,並輸入控制單元23,而控制單元23將依據電壓回授訊號VC 輸出控制訊號CS,以降低切換元件221的導通時間(即降低切換元件221的責任週期),以減少電源單元21的輸出功率,進而達到電源單元21的輸出與負載裝置L所需電力的平衡。If the driving signal DS becomes lighter and its voltage level rises, the voltage level of the voltage feedback signal V C also rises in the same proportion. In other words, when the voltage value of the driving signal DS rises due to the load of the load device L, the voltage feedback unit 25 can output a voltage feedback signal V C according to the voltage level of the rising driving signal DS, and input the control unit. 23, and the control unit 23 outputs the control signal CS according to the voltage feedback signal V C to reduce the conduction time of the switching element 221 (ie, reduce the duty cycle of the switching element 221) to reduce the output power of the power unit 21, thereby achieving the power supply. The output of unit 21 is balanced with the power required by load device L.
控制單元23係與轉換單元22及頻率線性調整單元24電性連接。其中,控制單元23係依據電壓回授訊號VC 及頻率線性調整單元24產生之一頻率調整訊號FS輸出控制訊號CS,以控制切換元件221。於此,控制單元23係整合電壓回授訊號VC 及頻率調整訊號FS並輸出控制訊號CS,以控制切換元件221。The control unit 23 is electrically connected to the conversion unit 22 and the frequency linear adjustment unit 24. The control unit 23 generates a frequency adjustment signal FS output control signal CS according to the voltage feedback signal V C and the frequency linear adjustment unit 24 to control the switching element 221. Here, the control unit 23 integrates the voltage feedback signal V C and the frequency adjustment signal FS and outputs a control signal CS to control the switching element 221.
控制單元23具有一頻率調整電容C1、一頻率調整電阻R5及一控制器231。其中,控制器231內具有控制IC(圖未顯示)及驅動切換元件221作動的電路。另外,頻率調整電容C1及一頻率調整電阻R5決定控制器231內之控制IC的振盪頻率。The control unit 23 has a frequency adjustment capacitor C1, a frequency adjustment resistor R5 and a controller 231. The controller 231 has a control IC (not shown) and a circuit for driving the switching element 221 to operate. Further, the frequency adjustment capacitor C1 and a frequency adjustment resistor R5 determine the oscillation frequency of the control IC in the controller 231.
頻率線性調整單元24係與電源單元21及控制單元23之頻率調整電容C1電性連接。頻率線性調整單元24係依據電源訊號PS產生頻率調整訊號FS。於此,頻率線性調整單元24係依據電源訊號PS的電壓準位產生頻率調整訊號FS。The frequency linearity adjustment unit 24 is electrically connected to the power supply unit 21 and the frequency adjustment capacitor C1 of the control unit 23. The frequency linearity adjusting unit 24 generates a frequency adjustment signal FS according to the power signal PS. Here, the frequency linearity adjusting unit 24 generates the frequency adjustment signal FS according to the voltage level of the power signal PS.
頻率線性調整單元24具有一第一電阻R1、一第二電阻R2及一開關元件S1。其中,第一電阻R1的第一端R11電性連接電源單元21的輸出端,第一電阻R1的第二端R12與第二電阻R2的第一端R21電性連接,第二電阻R2的第二端R22係接地。另外,第一電阻R1的第二端R12係藉由一限流電阻R6與開關元件S1的第一端S11電性連接。開關元件S1的第二端S12係電性連接頻率調整電容C1之第一端C11,而開關元件S1的第三端S13係電性接地。其中,開關元件S1的第二端S12係輸出頻率調整訊號FS,而頻率調整訊號FS係輸入頻率調整電容C1的第一端C11,以降低頻率調整電容C1的充電電流,使控制器231內之控制IC的振盪頻率降低,進而使控制訊號CS降低轉換單元22之切換頻率。The frequency linearity adjusting unit 24 has a first resistor R1, a second resistor R2, and a switching element S1. The first end R11 of the first resistor R1 is electrically connected to the output end of the power source unit 21, the second end R12 of the first resistor R1 is electrically connected to the first end R21 of the second resistor R2, and the second resistor R2 is The two ends R22 are grounded. In addition, the second end R12 of the first resistor R1 is electrically connected to the first end S11 of the switching element S1 via a current limiting resistor R6. The second end S12 of the switching element S1 is electrically connected to the first end C11 of the frequency adjusting capacitor C1, and the third end S13 of the switching element S1 is electrically grounded. The second end S12 of the switching element S1 outputs a frequency adjustment signal FS, and the frequency adjustment signal FS is input to the first end C11 of the frequency adjustment capacitor C1 to reduce the charging current of the frequency adjustment capacitor C1, so that the controller 231 is within the controller 231. The oscillation frequency of the control IC is lowered, thereby causing the control signal CS to lower the switching frequency of the conversion unit 22.
切換元件221及開關元件S1係可分別為雙載子接面電晶體(Bipolar Junction Transistor,BJT),或場效電晶體(Field Effect Transistor,FET)、或金屬氧化物半導體場效電晶體(Metal-Oxide-Semiconductor Field-Effect Transistor,MOSFET)。在本實施例中,切換元件221係以金屬氧化物半導體場效電晶體為例,而開關元件S1係以NPN型之雙載子接面電晶體為例。然並不以此為限制。The switching element 221 and the switching element S1 are respectively Bipolar Junction Transistor (BJT), Field Effect Transistor (FET), or Metal Oxide Semiconductor Field Effect Transistor (Metal) -Oxide-Semiconductor Field-Effect Transistor, MOSFET). In the present embodiment, the switching element 221 is exemplified by a metal oxide semiconductor field effect transistor, and the switching element S1 is exemplified by an NPN type double carrier junction transistor. However, this is not a limitation.
請再參照圖2B所示,以進一步說明頻率線性調整單元24係如何調整(降低)頻率調整電容C1的充電電流。Please refer to FIG. 2B again to further explain how the frequency linearity adjusting unit 24 adjusts (reduces) the charging current of the frequency adjusting capacitor C1.
由分壓定理可知,頻率線性調整單元24之節點A的電壓準位係等於R2×PS/(R1+R2)。換言之,節點A的電壓準位與電源訊號PS之電壓準位係成正比。若電源訊號PS之電壓準位升高,則節點A的電壓準位亦升高。反之亦然。It can be seen from the partial pressure theorem that the voltage level of the node A of the frequency linearity adjusting unit 24 is equal to R2 × PS / (R1 + R2). In other words, the voltage level of the node A is proportional to the voltage level of the power signal PS. If the voltage level of the power signal PS rises, the voltage level of the node A also rises. vice versa.
當節點A的電流經由限流電阻R6輸入開關元件S1的第一端S11時,可導通開關元件S1,使開關元件S1之第二端S12輸出頻率調整訊號FS。於此,輸入開關元件S1第一端S11之電流可控制開關元件S1的導通比例,使電流1經由開關元件S1的第二端S12流向第三端S13。因此,原本流入頻率調整電容C1的第一端C11之充電電流的一部分將被分流,並由開關元件S1的第二端S12流向第三端S13,使得流入頻率調整電容C1的充電電流減少。因此,頻率調整訊號FS可降低控制單元23之頻率調整電容C1的充電電流,使頻率調整電容C1的充電時間增加,進而可降低控制器231內之控制IC的振盪頻率。藉此,可透過控制單元23輸出之控制訊號CS降低切換元件221的切換頻率。降低切換元件221的切換頻率,即降低切換元件221導通與截止的切換次數,故可減少切換元件221切換時之暫態損失,進而降低電源控制電路2的損耗並提升效率。因此,電源控制電路2可依據電源單元21輸出之電源訊號PS調整(降低)轉換單元22之切換元件221的切換頻率,故可減少切換元件221切換時之暫態損失,進而可提高電源控制電路2的效率。When the current of the node A is input to the first terminal S11 of the switching element S1 via the current limiting resistor R6, the switching element S1 can be turned on, and the second terminal S12 of the switching element S1 outputs the frequency adjustment signal FS. Here, the current input to the first terminal S11 of the switching element S1 can control the conduction ratio of the switching element S1, so that the current 1 flows to the third terminal S13 via the second end S12 of the switching element S1. Therefore, a part of the charging current originally flowing into the first end C11 of the frequency adjusting capacitor C1 is shunted, and flows from the second end S12 of the switching element S1 to the third end S13, so that the charging current flowing into the frequency adjusting capacitor C1 is reduced. Therefore, the frequency adjustment signal FS can reduce the charging current of the frequency adjustment capacitor C1 of the control unit 23, increase the charging time of the frequency adjustment capacitor C1, and further reduce the oscillation frequency of the control IC in the controller 231. Thereby, the switching frequency of the switching element 221 can be reduced by the control signal CS outputted by the control unit 23. The switching frequency of the switching element 221 is lowered, that is, the number of switching of the switching element 221 is reduced, so that the transient loss when the switching element 221 is switched can be reduced, thereby reducing the loss of the power supply control circuit 2 and improving the efficiency. Therefore, the power control circuit 2 can adjust (lower) the switching frequency of the switching element 221 of the conversion unit 22 according to the power signal PS outputted by the power unit 21, so that the transient loss when the switching element 221 is switched can be reduced, thereby improving the power control circuit. 2 efficiency.
特別說明的是,因節點A的電壓準位與電源訊號PS之電壓準位係成正比,且輸入開關元件S1第一端S11之電流可控制開關元件S1的導通比例,使電流I經由開關元件S1的第二端S12流向第三端S13。因此,本發明之頻率線性調整單元24係可線性地調整切換元件221的切換頻率。另外,當電源訊號PS之電壓準位越高時,頻率線性調整單元24之節點A的電壓準位越高,使得輸入開關元件S1的第一端S11的電流亦越高,使開關元件S1導通比例越高,進而使頻率調整電容C1的充電電流越小,使控制訊號CS控制切換元件221之切換頻率降低越多。因此,電源控制電路2的切換的損耗將更低。當負載越低時,與習知電路相較,電源控制電路2的效率將可提升更多。Specifically, since the voltage level of the node A is proportional to the voltage level of the power signal PS, and the current of the first terminal S11 of the input switching element S1 can control the conduction ratio of the switching element S1, the current I is passed through the switching element. The second end S12 of S1 flows to the third end S13. Therefore, the frequency linear adjustment unit 24 of the present invention can linearly adjust the switching frequency of the switching element 221. In addition, when the voltage level of the power signal PS is higher, the voltage level of the node A of the frequency linearity adjusting unit 24 is higher, so that the current of the first terminal S11 of the input switching element S1 is higher, and the switching element S1 is turned on. The higher the ratio, the smaller the charging current of the frequency adjustment capacitor C1, and the more the switching frequency of the control signal CS control switching element 221 is lowered. Therefore, the loss of switching of the power supply control circuit 2 will be lower. When the load is lower, the efficiency of the power supply control circuit 2 can be improved more than the conventional circuit.
請同時參照圖3A及圖3B所示,其分別為本發明第二實施例之一種電源控制電路3的功能方塊示意圖及電路示意圖。Please refer to FIG. 3A and FIG. 3B simultaneously, which are respectively a functional block diagram and a circuit diagram of a power control circuit 3 according to a second embodiment of the present invention.
電源控制電路3包括一電源單元31、一轉換單元32、一控制單元33、一頻率線性調整單元34以及一電壓回授單元35。另外,本實施例之電源控制電路3與第一實施例之電源控制電路2主要的不同在於,電源控制電路3更可包括一電流回授單元36。其中,電流回授單元36係為一前饋回授電路。The power control circuit 3 includes a power supply unit 31, a conversion unit 32, a control unit 33, a frequency linear adjustment unit 34, and a voltage feedback unit 35. In addition, the main difference between the power supply control circuit 3 of the present embodiment and the power supply control circuit 2 of the first embodiment is that the power supply control circuit 3 further includes a current feedback unit 36. The current feedback unit 36 is a feedforward feedback circuit.
電流回授單元36係與轉換單元32及控制單元33電性連接。電流回授單元36係依據轉換單元32產生一電流回授訊號RS,並輸入控制單元33。其中,電流回授單元36係將轉換單元32之一次側輸入電流加以轉換,以輸出電流回授訊號RS,並輸入控制單元33。在本實施例中,電流回授單元36係為一電阻R7。電流回授單元36係將輸入轉換單元32一次側之電流藉由電阻R7轉換成電流回授訊號RS後輸入控制單元33。實際上,電流回授訊號RS亦為電壓訊號。The current feedback unit 36 is electrically connected to the conversion unit 32 and the control unit 33. The current feedback unit 36 generates a current feedback signal RS according to the conversion unit 32 and inputs it to the control unit 33. The current feedback unit 36 converts the primary side input current of the conversion unit 32 to output a current feedback signal RS and inputs it to the control unit 33. In the present embodiment, the current feedback unit 36 is a resistor R7. The current feedback unit 36 converts the current on the primary side of the input conversion unit 32 into a current feedback signal RS by the resistor R7 and inputs it to the control unit 33. In fact, the current feedback signal RS is also a voltage signal.
控制單元33係依據頻率調整訊號FS、電壓回授訊號VC 及電流回授訊號RS產生控制訊號CS,以控制切換元件321。換言之,在本實施例中,控制單元33係整合頻率調整訊號FS、電壓回授訊號VC 及電流回授訊號RS並輸出控制訊號CS,以控制切換元件321的之責任週期及切換頻率。其中,控制訊號CS係依據電壓回授訊號VC 及電流回授訊號RS控制切換元件321之責任週期,並依據頻率調整訊號FS控制切換元件321之切換頻率。The control unit 33 generates the control signal CS according to the frequency adjustment signal FS, the voltage feedback signal V C and the current feedback signal RS to control the switching element 321 . In other words, in the embodiment, the control unit 33 integrates the frequency adjustment signal FS, the voltage feedback signal V C and the current feedback signal RS and outputs the control signal CS to control the duty cycle and the switching frequency of the switching element 321 . The control signal CS controls the duty cycle of the switching component 321 according to the voltage feedback signal V C and the current feedback signal RS, and controls the switching frequency of the switching component 321 according to the frequency adjustment signal FS.
此外,電源控制電路3之電源單元31、轉換單元32、控制單元33、頻率線性調整單元34及電壓回授單元35的技術內容可參照電源控制電路之電源單元21、轉換單元22、控制單元23、頻率線性調整單元24及電壓回授單元25,於此不再贅述。In addition, the technical contents of the power supply unit 31, the conversion unit 32, the control unit 33, the frequency linear adjustment unit 34, and the voltage feedback unit 35 of the power supply control circuit 3 can refer to the power supply unit 21, the conversion unit 22, and the control unit 23 of the power supply control circuit. The frequency linearity adjusting unit 24 and the voltage feedback unit 25 are not described herein again.
因此,與第一實施例相同的是,本實施例之頻率調整訊號FS可降低頻率調整電容C1之充電電流,使頻率調整電容C1的充電時間增加,進而可降低控制器331內之控制IC的振盪頻率。藉此,可透過控制單元33輸出之控制訊號CS降低切換元件321的切換頻率,故可減少切換元件321切換時之暫態損失,進而可降低電源控制電路3損耗並提升效率。因此,本發明之電源控制電路3可依據電源單元31輸出之電源訊號PS降低轉換單元32之切換元件331的切換頻率,以降低轉換單元32的切換損失,進而可提升電源控制電路3的效率。Therefore, the same as the first embodiment, the frequency adjustment signal FS of the embodiment can reduce the charging current of the frequency adjustment capacitor C1, increase the charging time of the frequency adjustment capacitor C1, and further reduce the control IC in the controller 331. Oscillation frequency. Thereby, the switching frequency of the switching element 321 can be reduced by the control signal CS outputted by the control unit 33, so that the transient loss when the switching element 321 is switched can be reduced, and the power supply control circuit 3 can be reduced and the efficiency can be improved. Therefore, the power control circuit 3 of the present invention can reduce the switching frequency of the switching element 331 of the conversion unit 32 according to the power signal PS outputted by the power supply unit 31, so as to reduce the switching loss of the conversion unit 32, thereby improving the efficiency of the power supply control circuit 3.
綜上所述,因依據本發明之電源控制電路的頻率線性調整單元係依據電源單元輸出之電源訊號產生一頻率調整訊號,而頻率調整訊號係輸入控制單元之頻率調整電容的第一端。藉此,可依據電源單元輸出之電源訊號的電壓準位降低控制單元之頻率調整電容的充電電流,進而增加頻率調整電容的充電時間,使控制單元內之控制IC的振盪頻率降低,進而降低轉換單元之切換元件的切換損失。與習知相較,本發明之電源控制電路可依據輸入電壓調整(降低)轉換單元之切換元件的切換頻率,故可減少切換元件切換時之暫態損失,進而可提高電源控制電路的效率。In summary, the frequency linear adjustment unit of the power control circuit according to the present invention generates a frequency adjustment signal according to the power signal outputted by the power unit, and the frequency adjustment signal is input to the first end of the frequency adjustment capacitor of the control unit. Therefore, the charging current of the frequency adjustment capacitor of the control unit can be reduced according to the voltage level of the power signal output by the power unit, thereby increasing the charging time of the frequency adjusting capacitor, thereby reducing the oscillation frequency of the control IC in the control unit, thereby reducing the conversion. Switching loss of the switching elements of the unit. Compared with the conventional one, the power control circuit of the present invention can adjust (lower) the switching frequency of the switching element of the conversion unit according to the input voltage, thereby reducing the transient loss when the switching element is switched, thereby improving the efficiency of the power control circuit.
以上所述僅為舉例性,而非為限制性者。任何未脫離本發明之精神與範疇,而對其進行之等效修改或變更,均應包含於後附之申請專利範圍中。The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.
1、2、3...電源控制電路1, 2, 3. . . Power control circuit
11、21、31...電源單元11, 21, 31. . . Power unit
12、22、32...轉換單元12, 22, 32. . . Conversion unit
13、25、35...電壓回授單元13, 25, 35. . . Voltage feedback unit
14、23、33...控制單元14, 23, 33. . . control unit
221、321...切換元件221, 321. . . Switching element
231、331...控制器231, 331. . . Controller
24、34...頻率線性調整單元24, 34. . . Frequency linear adjustment unit
36...電流回授單元36. . . Current feedback unit
A...節點A. . . node
C1...頻率調整電容C1. . . Frequency adjustment capacitor
C11、R11、R12、R21、R22、S11、S12、S13...端C11, R11, R12, R21, R22, S11, S12, S13. . . end
CS...控制訊號CS. . . Control signal
DS...驅動訊號DS. . . Drive signal
FS...頻率調整訊號FS. . . Frequency adjustment signal
I...電流I. . . Current
L...負載裝置L. . . Load device
PS...電源訊號PS. . . Power signal
R1、R2、R3、R4、R5、R6、R7...電阻R1, R2, R3, R4, R5, R6, R7. . . resistance
RS...電流回授訊號RS. . . Current feedback signal
S1...開關元件S1. . . Switching element
V...電壓V. . . Voltage
VC ...電壓回授訊號V C . . . Voltage feedback signal
圖1習知一種電源控制電路的功能方塊圖;1 is a functional block diagram of a power control circuit;
圖2A為本發明第一實施例之一種電源控制電路的功能方塊示意圖;2A is a functional block diagram of a power control circuit according to a first embodiment of the present invention;
圖2B為本發明第一實施例之一種電源控制電路的電路示意圖;2B is a schematic circuit diagram of a power control circuit according to a first embodiment of the present invention;
圖3A為本發明第二實施例之一種電源控制電路的功能方塊示意圖;以及3A is a functional block diagram of a power control circuit according to a second embodiment of the present invention;
圖3B為本發明第二實施例之一種電源控制電路的電路示意圖。FIG. 3B is a schematic circuit diagram of a power control circuit according to a second embodiment of the present invention.
2...電源控制電路2. . . Power control circuit
21...電源單元twenty one. . . Power unit
22...轉換單元twenty two. . . Conversion unit
23...控制單元twenty three. . . control unit
24...頻率線性調整單元twenty four. . . Frequency linear adjustment unit
25...電壓回授單元25. . . Voltage feedback unit
C1...頻率調整電容C1. . . Frequency adjustment capacitor
C11...端C11. . . end
CS...控制訊號CS. . . Control signal
DS...驅動訊號DS. . . Drive signal
FS...頻率調整訊號FS. . . Frequency adjustment signal
L...負載裝置L. . . Load device
PS...電源訊號PS. . . Power signal
VC ...電壓回授訊號V C . . . Voltage feedback signal
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TWI756153B (en) * | 2021-07-06 | 2022-02-21 | 亞源科技股份有限公司 | Power supply device capable of saving power supply notification pin and method of operation the same |
CN113472221A (en) * | 2021-07-30 | 2021-10-01 | 亚瑞源科技(深圳)有限公司 | Power supply capable of omitting power supply informing pin and operation method thereof |
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2011
- 2011-01-06 TW TW100100520A patent/TWI435518B/en not_active IP Right Cessation
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TW201230627A (en) | 2012-07-16 |
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MM4A | Annulment or lapse of patent due to non-payment of fees |