200810332 九、發明說明： 【發明所屬之技術領域】 本發明係關於脈寬調變的技術，尤指一種在脈寬調變 .控制器實現多功能腳位的電路。 5 【先前技術】 圖1係一習知之電壓轉換器20,其中脈寬調變控制器22 切換一對串聯在輸入電壓Vin及接地電位GND之間的電晶 體24及28，以導通一輸出電流I通過相節點26，控制器22具 10 有一多功能腳腳PH透過電阻Rs連接至相節點26，此外一電 晶體29連接在多功能腳位PH及接地電位GND之間，受控於 致能信號Ve。在控制器22中，雙電源感測器221與比較器222 組成一電源感測裝置，比較器223與電流源224組成過電流 保護裝置，而電晶體29與比較器225組成一致能裝置。在致 15 能裝置中，比較器225的非反相輸入端連接至多功能腳位 PH，而其反相輸入瑞則連接電壓Ven，當啟動電壓轉換器 20時，致能信號Ve關閉電晶體29，此時，如果多功能腳位 PH上的電壓高於電壓Ven，比較器225輸出一信號ENI致能 脈寬調變控制器22。在控制器22被致能後，輸出電壓Vout 20 仍為零，而驅動器226及227尚無信號輸入，此時雙電源感 測器221 —方面感測電源電壓Vccl，一方面輸出一確認信號 pre-check至驅動器226，以導通電晶體24，這時比較器222 比較多功能腳位PH上的電壓及參考電壓Vinp or，若多功能 腳位PH上的電壓高於參考電壓Vinpor，表示輸入電壓Vin 5 200810332 比較器轉出信號職至雙電源感測器22i，當 又電源感.221感測到電源電磨Vccl也被啟 號顺，使脈寬調變控制電路⑽產生信號Μ及W，以^ 別透過驅動器226及227切換電晶體24及28，而產生輸出二 =而在：知之電壓轉換器，中需增添一雙電源感測器 ☆不僅增加電Μ轉換器2G積體電路的成本200810332 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to a technique for pulse width modulation, and more particularly to a circuit for implementing a multi-function pin in a pulse width modulation. 5 [Prior Art] FIG. 1 is a conventional voltage converter 20 in which a pulse width modulation controller 22 switches a pair of transistors 24 and 28 connected in series between an input voltage Vin and a ground potential GND to turn on an output current. I pass through the phase node 26, the controller 22 has a multi-function foot PH connected to the phase node 26 through the resistor Rs, and a transistor 29 is connected between the multi-function pin PH and the ground potential GND, controlled by Can signal Ve. In the controller 22, the dual power sensor 221 and the comparator 222 constitute a power sensing device, the comparator 223 and the current source 224 constitute an overcurrent protection device, and the transistor 29 and the comparator 225 constitute a uniform energy device. In the 15-energy device, the non-inverting input of the comparator 225 is connected to the multi-function pin PH, and the inverting input R is connected to the voltage Ven. When the voltage converter 20 is activated, the enable signal Ve turns off the transistor 29 At this time, if the voltage on the multi-function pin PH is higher than the voltage Ven, the comparator 225 outputs a signal ENI to enable the pulse width modulation controller 22. After the controller 22 is enabled, the output voltage Vout 20 is still zero, and the drivers 226 and 227 have no signal input. At this time, the dual power sensor 221 senses the power supply voltage Vccl, and outputs an acknowledge signal pre. -check to the driver 226 to conduct the crystal 24, the comparator 222 compares the voltage on the multi-function pin PH and the reference voltage Vinp or, if the voltage on the multi-function pin PH is higher than the reference voltage Vinpor, the input voltage Vin 5 200810332 The comparator turns out the signal to the dual power sensor 22i, when the power sense 221 senses that the power supply grind Vccl is also turned on, so that the pulse width modulation control circuit (10) generates signals Μ and W, ^ Do not switch the transistors 24 and 28 through the drivers 226 and 227, and produce the output two = and in the: known voltage converter, need to add a pair of power sensors ☆ not only increase the cost of the 2G integrated circuit of the power converter
器221為類比電路，更增加電壓轉換器2。的積體 电路里產¥的失敗率。知之電㈣換器仍存有諸多: 缺失而有予以改進之必要。 10 【發明内容】 本發明之一目的係在提供一種在脈寬調變控制器實現 多功能腳位的電路，俾減少脈寬調變控制器之元件數目， 以減少脈寬調變控制器之成本。 15 纟發明之另—目的係在提供-種在脈寬調變控制器實 現多功能腳位的電路，俾減少脈寬調變 目’以增加電壓轉換器量產時的成功率。 本發明之再一目的係在提供一種在脈寬調變控制器實 現多功能腳位的電路，俾減少接腳數目，以降低電壓轉換 20 器量之成本。 ' *。依，本發明之-特色，本發明係提出—種在脈寬調變 控制器實現多功能腳位的電路，該脈寬調變控制器係用以 切換一連接在一輸入電壓及一相位節點之間的高位側開關 元件及連接在该相位節點及一接地電位之間的低位側開 200810332 關兀件’該電路包含一多功能接腳、一致能裝置、一脈 調，控制電路、一外部電源偵測器及一過電流保護裝置： 该多功能接腳連接該相位節點；該致能裝 =用，編多功能接腳上之電壓，俾致能該。 r':\ 10 又工制益’當該脈寬調變控制器被致能後，該脈寬調變 t制電路輸出-脈寬調變訊號，以導通該高位侧開關元 h該外部電源偵測器連接至該多功能接腳，用以偵測該 多功能接腳上之電壓’俾判斷該輸入電壓是否啟動；該過 電流保護裝置連接至該多功能接腳，用以伯測該多功能接 腳上之電壓，俾防止產生過大之輸出電流。 【實施方式】 圖2係本發明之在脈寬調變控制器3〇〇實現多功能腳位 的電路的方塊圖。該脈寬調變控制器300係用以切換一連接 15在-輸人電壓VIN2及-相位節點3G1之間的高位側開關元 件3 0 2及-連接在該相位節點3 Q i及—接地電位之間的低位 側開關元件303。 一多功能接腳310透過電阻尺連接該相位節點3〇1。一致 能開關304與-第三比較器32〇組成一致能裝置。該致能裝 置用以H亥夕功此接腳3 1 〇上之電壓，俾致能該脈寬調變 控制電路330。 致能開關3 0 4較佳為一電晶體3 〇 4，電晶體3 〇 4連接在該 々多功能接腳310及該接地電位之間，受控於—致能訊號犯。 第三比較器320之非反向輸入端連接至該多功能接聊㈣， 200810332 第三比較器320之反向輸入端連接至一第三參考電壓 VEN。第三比較器320比較第三參考電壓VEN及該多功能接 腳310上的電壓，俾產生一致能訊號εν，其中，該致能訊號 ΕΝ用以啟動脈寬調變控制器（Pwm)300。當要啓動脈寬調變 5 控制器（PWM)3 00以控制電壓轉換時，致能訊號SD電壓為低 電壓，此會關閉電晶體電晶體304。當多功能接腳310上的 電壓高於第三參考電壓VEN時，則致能訊號EN為高電位， 且PWM控制電路330便會被致能，於是PWM控制電路330開 始啓動並輸出其控制訊號P WM_OUT。 10 該脈寬調變控制電路330包含一誤差放大器331、一補 償電路332、及一第一比較器333。誤差放大器331的非反相 輸入端連接至第一參考電壓VREF而反相輸入端則連接至 脈寬調變控制電路330的回授輸入端FB。補償電路332連接 至該誤差放大器331的輸出端做為脈寬調變控制電路330的 15 補償之用，俾產生一誤差輸出電壓ERR—OUT。第一比較器 333的非反向輸入端連接至該補償電路332，第一比較器333 的反向輸入端接收一三角波訊號TRI-OSC。該第一比較器 333比較該誤差輸出電壓ERR-OUT及該三角波訊號 TRI-OSC，俾產生該脈寬調變訊號PWM—OUT。當該脈寬調 20 變控制器300被致能後，該脈寬調變控制電路330輸出_脈 寬調變訊號PWM—OUT，以導通一高位側開關元件3〇2。 外部電源偵測器340連接至該多功能接腳310，用以伯 測該多功能接腳3 10上之電壓，俾判斷該輸入電壓VIN2是否 啟動。外部電源偵測器340係由一第二比較器341所組成。 8 200810332 第二比較器341的非反向輸入端連接至該多功能接腳3丨〇， 第二比較器341的反向輸入端連接至一第二參考電壓 VIN2REF。第二比較器341比較該第二參考電壓VIN2REF及 該多功能接腳3 10上的電壓，俾產生一指示訊號νΙΝ2〇κ， 5 其中，該指示訊號VIN20K用以指示該輸入電壓νΐΝ2是否 啟動。 過電流保護裝置350連接至該多功能接腳3 1〇，用以偵 測該多功能接腳3 10上之電壓，俾防止產生過大之輸出電 流。過電流保護裝置350包含一電流源hi、及一第四比較 10 态3 52。電流源3 5 1連接至該多功能接腳3丨〇，以在該多功能 接腳3 10產生一偵測過電流之電壓。第四比較器3 52的反向 輸入端連接至該多功能接腳31〇，第四比較器352的非反向 輸入端連接至一第四參考電壓V0C。第四比較器352比較該 第四參考電壓VOC及該多功能接腳3 1〇上的偵測過電流之 15 電壓，俾產生一過電流訊號〇C，以防止輸出過大之電流。 當脈寬調變控制器300使得高位側開關元件3〇2截止且 低位側開關元件303導通時，相位節點3〇 1的電壓會等於 -IL*rd ’其中，rd為低位側開關元件3〇3導通時的電阻值。 當IL電流變大時，則相位節點3〇1的電壓也越低，相對多功 20能接腳310的電壓也會隨著降低。當多功能接腳310的電壓 低於voc電壓時，表示IL過大，第四比較器352輸出端輸出 高電位的過電流訊號〇C。 圖3係本發明之訊號波形的示意圖。當致能訊號^^^為 高電位時，誤差放大器331的軟啓動訊號SS為慢慢上升時， 9 200810332 誤差放大器331的誤差輸出電壓ERR_OUT會隨著軟啓動訊 號SS上升而上升。故如圖3所示，誤差輸出電壓ERR_〇UT 逐漸上升。在A點處，誤差輸出電壓ERR_OUT大於三角波 訊號TRI-OSC，故第一比較器333輸出脈寬調變訊號 5 PWM—OUT。當脈寬調變訊號PWM—OUT輸出為高電位時， 透過驅動器360使UGATE接腳也會輸出高電位，而造成高位 側開關元件302導通。此使得多功能接腳310的電壓會等於 VIN2+(IB*R)。若多功能接腳310的電壓高於外部電源偵測 器340的第二參考電壓VIN2REF，表示VIN2電壓己啓動。當 10 VIN2電壓己啓動時，該脈寬調變控制電路330則會持續輸出 脈寬調變訊號PWM_〇U丁或是將軟啓動訊號SS放電後再重 新啓動脈寬調變控制電路330。反之，則重複偵測或間隔一 段時間重複偵測，直到VIN2電壓啓動。本發明之外部電源 偵測器340相較於習知技術之雙電源感測器221減少了 15 pre-check的動作。 由上述說明可知，本發明技術使用脈寬調變控制器 (PWM)300既有的脈寬調變控制電路330，以取代習知的雙 電源感測器221，可減少脈寬調變控制器（pwM)300之元件 數目，而降低脈寬調變控制器之成本。又，本發明技術無 20 需使用類比電路的雙電源感測器221，可增加電壓轉換器量 產時的成功率。同時，本發明技術可減少接腳數目，以降 低電壓轉換器量之成本。 10 200810332 本發明所 而非僅限 上述實施例僅係為了方便說明而舉例而已， 主張之權利範圍自應以申請專利範圍所述為準， 於上述實施例。 5 【圖式簡單說明】 圖1係一習知之電壓轉換器的方塊圖。 能腳位的 圖2係本發明之在脈寬調變控制器實現多功 電路的方塊圖。 圖3係本發明之訊號波形的示意圖。 10 【主要元件符號說明】 電壓轉換器 20 脈寬調變控制器 電晶體 24 > 28 相節點 電晶體 29 雙電源感測器 15 比較器 222 比較器 電流源 224 比較器 ) 驅動器 226 、227 雙電源感測器 221 脈寬調變控制電路 228 20 脈寬調變控制器 300 多功能接腳 相位節點 301 高位側開關元件 低位側開關元件 303 致能開關 .第三比較器 320 脈寬調變控制電路 誤差放大器 331 補償電路 22 26 221 223 225 310 302 304 330 11 332 200810332 第一比較器 333 外部電源偵測器 340 第二比較器 341 過電流保護裝置 350 電流源 351 第四比較器 352 驅動器 360、 370The 221 is an analog circuit, and the voltage converter 2 is further added. The failure rate of the production of the circuit in the circuit. There are still many things to know about the electric (4) converter: missing and necessary to improve. [Embodiment] One object of the present invention is to provide a circuit for implementing a multi-function pin in a pulse width modulation controller, which reduces the number of components of the pulse width modulation controller to reduce the pulse width modulation controller. cost. 15 纟Inventive--The purpose is to provide a circuit for implementing a multi-function pin in a pulse width modulation controller, and to reduce the pulse width modulation to increase the success rate of the voltage converter during mass production. Still another object of the present invention is to provide a circuit for implementing a multi-function pin in a pulse width modulation controller, which reduces the number of pins to reduce the cost of the voltage conversion device. ' *. According to the present invention, the present invention provides a circuit for implementing a multi-function pin in a pulse width modulation controller for switching a connection to an input voltage and a phase node. The high-side switching element and the low-side side connected between the phase node and a ground potential are opened. The circuit includes a multi-function pin, a uniform device, a pulse, a control circuit, and an external portion. The power detector and an overcurrent protection device: the multi-function pin is connected to the phase node; the enable device is used, and the voltage on the multi-function pin is enabled. r':\10, and the system is beneficial. When the pulse width modulation controller is enabled, the pulse width modulation t system output-pulse width modulation signal is turned on to turn on the high side switch element h. The detector is connected to the multi-function pin for detecting the voltage on the multi-function pin', determining whether the input voltage is activated; the overcurrent protection device is connected to the multi-function pin for testing The voltage on the multi-function pin prevents excessive output current. [Embodiment] FIG. 2 is a block diagram showing a circuit for realizing a multi-function pin in the pulse width modulation controller 3 of the present invention. The pulse width modulation controller 300 is configured to switch a connection side 15 between the input voltage VIN2 and the -phase node 3G1, and to connect to the phase node 3 Q i and the ground potential Between the lower side switching elements 303. A multi-function pin 310 is connected to the phase node 3〇1 through a resistor. The uniformity switch 304 and the -third comparator 32 are combined to form a uniform energy device. The enabling means is operative to apply the voltage on the pin 3 1 俾 to enable the pulse width modulation control circuit 330. The enable switch 306 is preferably a transistor 3 〇 4, and the transistor 3 〇 4 is connected between the 々 multi-function pin 310 and the ground potential, controlled by the enable signal. The non-inverting input of the third comparator 320 is connected to the multi-function chat (4), and the inverting input of the third comparator 320 is connected to a third reference voltage VEN. The third comparator 320 compares the third reference voltage VEN with the voltage on the multi-function pin 310 to generate a uniform energy signal εν, wherein the enable signal 启动 is used to activate the pulse width modulation controller (Pwm) 300. When the pulse width modulation 5 controller (PWM) 3 00 is to be started to control the voltage conversion, the enable signal SD voltage is low, which turns off the transistor transistor 304. When the voltage on the multi-function pin 310 is higher than the third reference voltage VEN, the enable signal EN is high, and the PWM control circuit 330 is enabled, so the PWM control circuit 330 starts to start and outputs its control signal. P WM_OUT. The pulse width modulation control circuit 330 includes an error amplifier 331, a compensation circuit 332, and a first comparator 333. The non-inverting input of error amplifier 331 is coupled to a first reference voltage VREF and the inverting input is coupled to a feedback input FB of pulse width modulation control circuit 330. The compensation circuit 332 is connected to the output of the error amplifier 331 for compensation of the pulse width modulation control circuit 330, and generates an error output voltage ERR_OUT. The non-inverting input of the first comparator 333 is coupled to the compensation circuit 332, and the inverting input of the first comparator 333 receives a triangular wave signal TRI-OSC. The first comparator 333 compares the error output voltage ERR-OUT with the triangular wave signal TRI-OSC to generate the pulse width modulation signal PWM_OUT. When the pulse width modulation controller 300 is enabled, the pulse width modulation control circuit 330 outputs a pulse width modulation signal PWM_OUT to turn on a high side switching element 3〇2. The external power detector 340 is connected to the multi-function pin 310 for detecting the voltage on the multi-function pin 3 10 and determining whether the input voltage VIN2 is activated. The external power detector 340 is composed of a second comparator 341. 8 200810332 The non-inverting input of the second comparator 341 is connected to the multi-function pin 3, and the inverting input of the second comparator 341 is connected to a second reference voltage VIN2REF. The second comparator 341 compares the voltage between the second reference voltage VIN2REF and the multi-function pin 3 10 to generate an indication signal ν ΙΝ 2 〇 κ, 5 , wherein the indication signal VIN 20K is used to indicate whether the input voltage ν ΐΝ 2 is activated. The overcurrent protection device 350 is connected to the multi-function pin 3 1 〇 to detect the voltage on the multi-function pin 3 10 and prevent excessive output current from being generated. The overcurrent protection device 350 includes a current source hi and a fourth comparison state 3 52. A current source 3 5 1 is connected to the multi-function pin 3 以 to generate a voltage for detecting an overcurrent at the multi-function pin 3 10 . The inverting input of the fourth comparator 3 52 is coupled to the multi-function pin 31, and the non-inverting input of the fourth comparator 352 is coupled to a fourth reference voltage V0C. The fourth comparator 352 compares the voltage of the fourth reference voltage VOC and the detected overcurrent on the multi-function pin 3 1〇, and generates an overcurrent signal 〇C to prevent an excessive current from being output. When the pulse width modulation controller 300 turns off the high side switching element 3〇2 and the low side switching element 303 turns on, the voltage of the phase node 3〇1 will be equal to −IL*rd 'where rd is the low side switching element 3〇 3 resistance value when turned on. When the IL current becomes larger, the voltage of the phase node 3〇1 is also lower, and the voltage of the multi-function 20 pin 310 is also lowered. When the voltage of the multi-function pin 310 is lower than the voc voltage, it indicates that the IL is too large, and the output of the fourth comparator 352 outputs a high-potential overcurrent signal 〇C. Figure 3 is a schematic illustration of the signal waveform of the present invention. When the enable signal ^^^ is at a high level, the soft start signal SS of the error amplifier 331 is slowly rising, and the error output voltage ERR_OUT of the error amplifier 331 rises as the soft start signal SS rises. Therefore, as shown in FIG. 3, the error output voltage ERR_〇UT gradually rises. At point A, the error output voltage ERR_OUT is greater than the triangular wave signal TRI-OSC, so the first comparator 333 outputs the pulse width modulation signal 5 PWM_OUT. When the pulse width modulation signal PWM_OUT output is high, the UGATE pin is also outputted through the driver 360, and the high side switching element 302 is turned on. This causes the voltage of the multi-function pin 310 to be equal to VIN2+(IB*R). If the voltage of the multi-function pin 310 is higher than the second reference voltage VIN2REF of the external power detector 340, it indicates that the VIN2 voltage has been activated. When the voltage of the VIN2 is activated, the pulse width modulation control circuit 330 continues to output the pulse width modulation signal PWM_〇U or discharges the soft start signal SS and then restarts the pulse width modulation control circuit 330. Otherwise, the detection is repeated or repeated for a period of time until the VIN2 voltage is activated. The external power detector 340 of the present invention reduces the 15 pre-check action compared to the prior art dual power sensor 221. As can be seen from the above description, the present invention uses the pulse width modulation control circuit 330 of the pulse width modulation controller (PWM) 300 instead of the conventional dual power sensor 221 to reduce the pulse width modulation controller. (pwM) 300 the number of components, while reducing the cost of the pulse width modulation controller. Moreover, the present invention does not require a dual power sensor 221 that requires an analog circuit to increase the success rate of the voltage converter during mass production. At the same time, the technique of the present invention can reduce the number of pins to reduce the cost of the voltage converter. The present invention is not limited to the above-described embodiments, but is merely for the sake of convenience of description. The scope of the claims is based on the above-mentioned embodiments. 5 [Simple description of the drawing] Fig. 1 is a block diagram of a conventional voltage converter. Figure 2 is a block diagram of the multi-function circuit implemented by the pulse width modulation controller of the present invention. Figure 3 is a schematic illustration of the signal waveform of the present invention. 10 [Main component symbol description] Voltage converter 20 pulse width modulation controller transistor 24 > 28 phase node transistor 29 dual power sensor 15 comparator 222 comparator current source 224 comparator) driver 226, 227 double Power sensor 221 pulse width modulation control circuit 228 20 pulse width modulation controller 300 multi-function pin phase node 301 high-side switching element low-side switching element 303 enable switch. third comparator 320 pulse width modulation control Circuit error amplifier 331 compensation circuit 22 26 221 223 225 310 302 304 330 11 332 200810332 first comparator 333 external power detector 340 second comparator 341 overcurrent protection device 350 current source 351 fourth comparator 352 driver 360, 370
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