M391707 五、新型說明： 【新型所屬之技術領域】 [〇〇〇1]本創作係有關一種均流式背光源軀動系統’尤指一種具 有適應性控制功能之均流式背光滹驅動系統° [先前技術3 [0002]發光二極體（light emitting di〇de，LED)應用於可 攜式電子產品之背光源的地位已經不可動搖。在照明領 域，LED作為半導體照明最關鍵的部件’更是有許多的優 點，如節能、環保、長壽命、免維護…等等。而LED驅動 電路是LED產品的重要組成部分，無論在照明、背光源還 是顯示板領域，驅動電路技術架構的選擇都應與具體的 應用相匹配。 [0003] 利用脈衝寬度調變技術（puise Width Modulation， PWM)做為LED亮度（又稱為灰階绸光）的控制方法，係利 用簡單的數位脈衝，反覆開關LED#動器，系統只需要提 供寬、窄不同的數位式脈衝，透過開啟和關閉LED來改變 順向電流導通時間以達到亮度調參效果，如此能降低亮 度，又能產生數千種亮度階數，使色彩明暗變化更細緻 ’畫質呈現也更完美。M391707 V. New description: [New technology field] [〇〇〇1] This creation is about a current-flowing backlight body-moving system, especially a current-flowing backlight system with adaptive control function. [Prior Art 3 [0002] The position of a light emitting diode (LED) applied to a backlight of a portable electronic product has been unshakable. In the field of lighting, LEDs are the most critical components of semiconductor lighting. There are many advantages, such as energy saving, environmental protection, long life, maintenance-free...etc. The LED driver circuit is an important part of the LED product. Whether in the field of illumination, backlight or display panel, the choice of the driver circuit technology architecture should be matched with the specific application. [0003] Using pulse width modulation (PWM) as the control method of LED brightness (also known as grayscale silk), using a simple digital pulse, repeatedly switching LED# actuator, the system only needs Provide wide and narrow digital pulse, change the forward current conduction time by turning on and off the LED to achieve the brightness adjustment effect, which can reduce the brightness, and can generate thousands of brightness orders, making the color shades more detailed. 'The quality of the picture is also more perfect.
[0004] 請參見第一圖，係習知背光源驅動系統之電路方塊圖。 該背光源驅動系統基本上係包含一EMI濾波器10A、一整 流器20A、一功率因數校正器3〇A、一隔離式DC/DC轉換 器40A、複數個非隔離式dc/DC轉換器50A[0004] Referring to the first figure, it is a circuit block diagram of a conventional backlight driving system. The backlight driving system basically comprises an EMI filter 10A, a rectifier 20A, a power factor corrector 3A, an isolated DC/DC converter 40A, and a plurality of non-isolated dc/DC converters 50A.
(50A一卜50A_N)以及複數個發光二極體燈串60A 表單編號A0101 第4頁/共24頁 M391707 (60A_卜60A—N)。該£肘1濾波器10A係電性連接一交流電 源Vs，用以消除通過交流線路之雜訊，以防止與該背光 源驅動系統連接在同一電力系統的其他裝置，所產生的 傳導性電磁雜訊經由電源導線而彼此互相干擾。該整流 器20A係電性連接該EMI濾波器1〇A，用以將該EMI濾波器 10A之輸出交流電源轉換為直流電源。該功率因數校正器 30A係電性連接該整流器20A，用以改善該背光源驅動系 統輸入端之功率因數。該隔離式DC/DC轉換器4〇A係主要 包含複數個功率開關（未圖示）及一主變壓器.（未圖示）。 該隔離式DC/DC轉換器40A係電性連接該功率因數校正器 30A ’可藉由脈波寬度調變技術控制該些功率開關，以提 供該主變壓器一次側之電壓，使得該功率因數校正器3〇a 之輸出直流電源經由該主變Μ器做為一次柄輸入與二次 側輸出之間能量轉換。該些非隔離式DC/DC轉換器50Α係 分別電性連接該隔離式DC/DC轉換器40Α，以提供不同直 流電壓準位需求之裝置使用。該些發先體燈串6〇Α係 分別對應地電性連接該些非隔餘式DC?DC轉換器50A。其 中，該些發光二極體燈串60A之ϋ係與該些非隔離式 DC/DC轉換器50Α之數量相等。 [00〇5] 惟，因為每一該些發光二極體燈串60Α之順偏電壓有所差 異，因此，必須透過該些非隔離式DC/DC轉換器50Α針對 該些相異順偏電壓之該些發光二極體燈串60Α予以各別驅 動，以達成每一該些發光二極體燈串60AJ〜60Α_Ν分別 具有相同電壓或電流。由於每一該些發光二極體燈串60Α 需由一非隔離式DC/DC轉換器50Α對應控制，故此，將大 表單編號Α0101 第5頁/共24頁 M391707 大地增加使用該些非隔離式DC/DC轉換器50A之價格，特 別是在於中、大型以上之背光源驅動系統尤以明顯。 [0006] 因此，如何設計出一種能改善習知缺失之一種具有線性 電壓調整器之均流式背光源驅動系統，乃為本案創作人 所欲行克服並加以解決的一大課題。 【新型内容】 [0007] 為了達成上述目的，本創作係提供一種具有適應性控制 功能之均流式背光源驅動系統，係透過一外部之交流電 源，經電源交直流轉換後，對多組發光二極體燈串供電 ，以提供背光照明之應用。該均流式背光源驅動系統係 包含一EMI濾波器、一整流器、一功率因數校正器、一隔 離式DC/DC轉換器、複數個發光二極體燈串、複數個線性 電壓調整器、一定電流/定電壓補償器、一光耦合隔離器 以及一控制器。 [0008] 該Ε ΜI濾波器，係電性連接該交流電源。該整流器，係電 性連接該ΕΜΙ濾波器，以將該ΕΜΙ濾波器之輸出交流電源 轉換為直流電源。該功率因數校正器，係電性連接該整 流器，以改善該轉換後之直流電源之功率因數。該隔離 式DC/DC轉換器，係電性連接該功率因數校正器，以提供 不同直流電壓準位。每一該些發光二極體燈串係由複數 個發光二極體串聯組成，該些發光二極體燈串係為並聯 電性連接，並電性連接該隔離式DC/DC轉換器。每一該些 線性電壓調整器係對應電性連接該發光二極體燈串，以 調整每一該些發光二極體燈串具有相同電壓或電流。 表單編號Α0101 第6頁/共24頁 M391707 [0009] 該定電流/定電壓補償器，係電性連接該些發光二極體燈 串與該些線性電壓調整器，以偵測每一該些發光二極體 燈串之電壓與電流，以提供具有適應性控制之定電壓或 定電流補償，使每一該些發光二極體燈串分別具有相同 電壓或電流。 [0010] 該光耦合隔離器，係電性連接該定電流/定電壓補償器， 以接收該定電流/定電壓補償器所輸出之電壓或電流信號 ，並傳送該電壓或電流信號至另一隔離側，以達成電路 隔離效果。 [0011] 該控制器，係電性耦接該光耦合隔離器，以接收由該光 耦合隔離器所傳送之電壓或電流信號，以控制該功率因 數校正器與該隔離式DC/DC轉換器。 [0012] 藉此，利用該些線性電壓調整器調整該些發光二極體燈 串因不同支路阻抗，所造成之電壓與電流之差異，進而 提供均流控制，並透過該定電流/定電壓補償器所提供具 有適應性控制之定電壓或定電流補償，以提高該背光源 驅動系統之整體效率以及反應速度。。 [0013] 為了能更進一步瞭解本創作為達成預定目的所採取之技 術、手段及功效，請參閱以下有關本創作之詳細說明與 附圖，相信本創作之目的、特徵與特點，當可由此得一 深入且具體之瞭解，然而所附圖式僅提供參考與說明用 ，並非用來對本創作加以限制者。 【實施方式】 [0014] 有關本創作之技術内容及詳細說明，配合圖式說明如下 表單編號A0101 第7頁/共24頁 M391707 [0015] 請參見第二圖與第三圖，係分別為本創作均流式背光源 驅動系統之電路方塊圖以及具有線性電壓調整器之均流 式背光源驅動系統之電路方塊圖。該具有線性電壓調整 器之均流式背光源驅動系統，係透過一外部之交流電源 ，經電源交直流轉換後，對多組發光二極體燈串供電， 以提供背光照明之應用。該均流式背光源驅動系統係包 含一EMI濾波器10、一整流器20、一功率因數校正器30 、一隔離式DC/DC轉換器40、複數個發光二極體燈串60 (60_1~60_N)以及複數個線性電壓調整器50 (1 inear r egu 1 a t〇r ) (5 0_ 1 ~ 5 0_N )。該均流式背光源驅動系統 更包含一定電流/定電壓補償器70、一光耦合隔離器80以 及一控制器90。 [0016] 該EMI濾波器10係電性連接該交流電源Vs，以消除該交流 電源Vs之雜訊，並防止傳導性電磁雜訊之干擾。該整流 器20係電性連接該EMI濾波器10，以將該EMI濾波器10之 輸出交流電源轉換為直流電源。該功率因數校正器30係 電性連接該整流器20，以改善該轉換後之直流電源之功 率因數。該隔離式DC/DC轉換器40係主要包含複數個功率 開關（未圖示）及一主變壓器（未圖示）。該隔離式DC/DC 轉換器40係電性連接該功率因數校正器30，做為該主變 壓器一次侧輸入與二次侧輸出之間能量轉換，以提供不 同直流電壓準位。其中，該隔離式DC/DC轉換器40係可為 一返馳式（flyback)轉換器、一順向式（forward)轉換 器、一推挽式（push-pull)轉換器、一半橋式 表單編號A0101 第8頁/共24頁 M391707 (half-bridge)轉換器或一全橋式（full-bridge)轉換 器。(50A-Bu 50A_N) and a plurality of LED strings 60A Form No. A0101 Page 4 of 24 M391707 (60A_Bu 60A-N). The elbow 1 filter 10A is electrically connected to an alternating current power source Vs for eliminating noise passing through the alternating current line to prevent other devices connected to the backlight power supply system from being connected to the same power system, and generating conductive electromagnetic impurities. The signals interfere with each other via the power supply wires. The rectifier 20A is electrically connected to the EMI filter 1A for converting the output AC power of the EMI filter 10A into a DC power source. The power factor corrector 30A is electrically coupled to the rectifier 20A for improving the power factor of the input of the backlight drive system. The isolated DC/DC converter 4A includes a plurality of power switches (not shown) and a main transformer (not shown). The isolated DC/DC converter 40A is electrically connected to the power factor corrector 30A'. The power switches can be controlled by a pulse width modulation technique to provide a voltage on the primary side of the main transformer, so that the power factor correction The output DC power of the device 3〇a is used as the energy conversion between the primary handle input and the secondary side output via the primary converter. The non-isolated DC/DC converters 50 are electrically connected to the isolated DC/DC converters 40A to provide devices with different DC voltage levels. The precursor light strings 6 are electrically connected to the non-isolated DC/DC converters 50A, respectively. The illuminating diode strings 60A are equal in number to the non-isolated DC/DC converters 50A. [00〇5] However, since each of the LED strings 60 Α has a different bias voltage, it is necessary to pass the non-isolated DC/DC converters 50 Α for the different parasitic voltages. The light-emitting diode strings 60A are driven separately to achieve the same voltage or current for each of the LED strings 60AJ-60Α_Ν. Since each of the LED strings 60Α needs to be controlled by a non-isolated DC/DC converter 50Α, the large form number Α0101 5th page/24 pages M391707 is used to increase the non-isolated type. The price of the DC/DC converter 50A is particularly evident in backlight drive systems of medium and large size. [0006] Therefore, how to design a current-sharing backlight driving system with a linear voltage regulator that can improve the conventional knowledge is a major problem that the creator of the present invention has to overcome and solve. [New Content] [0007] In order to achieve the above objectives, the present invention provides a current-sequence backlight driving system with adaptive control function, which is an external AC power source, and is converted into multiple groups after being converted by AC and DC power. The diode string is powered to provide backlighting applications. The current sharing backlight driving system comprises an EMI filter, a rectifier, a power factor corrector, an isolated DC/DC converter, a plurality of LED strings, a plurality of linear voltage regulators, and a certain A current/constant voltage compensator, an optically coupled isolator, and a controller. [0008] The ΜI filter is electrically connected to the AC power source. The rectifier is electrically connected to the ΕΜΙ filter to convert the output AC power of the ΕΜΙ filter into a DC power source. The power factor corrector is electrically connected to the rectifier to improve the power factor of the converted DC power source. The isolated DC/DC converter is electrically coupled to the power factor corrector to provide different DC voltage levels. Each of the light-emitting diode strings is composed of a plurality of light-emitting diodes connected in series, and the light-emitting diode strings are electrically connected in parallel and electrically connected to the isolated DC/DC converter. Each of the linear voltage regulators is electrically connected to the LED string to adjust each of the LED strings to have the same voltage or current. Form No. Α0101 Page 6 of 24 M391707 [0009] The constant current/constant voltage compensator electrically connects the LED strings and the linear voltage regulators to detect each of these The voltage and current of the LED string are provided to provide a constant voltage or constant current compensation with adaptive control such that each of the LED strings has the same voltage or current. [0010] the optically coupled isolator is electrically connected to the constant current/constant voltage compensator to receive a voltage or current signal output by the constant current/constant voltage compensator, and transmit the voltage or current signal to another Isolation side to achieve circuit isolation. [0011] the controller is electrically coupled to the optical coupling isolator to receive a voltage or current signal transmitted by the optical coupling isolator to control the power factor corrector and the isolated DC/DC converter . [0012] Thereby, the linear voltage regulators are used to adjust the difference between the voltage and the current caused by the different branch impedances of the light-emitting diode strings, thereby providing current sharing control and transmitting the constant current/determination The voltage compensator provides constant voltage or constant current compensation with adaptive control to improve the overall efficiency and reaction speed of the backlight drive system. . [0013] In order to further understand the techniques, means and effects of this creation in order to achieve the intended purpose, please refer to the following detailed description and drawings of the creation, and believe that the purpose, characteristics and characteristics of the creation can be obtained therefrom. The in-depth and specific understanding of the present invention is provided by way of illustration and description. [Embodiment] [0014] The technical content and detailed description of the creation, with the following description, the form number A0101, page 7 / total 24 pages M391707 [0015] Please refer to the second and third figures, respectively A block diagram of a circuit diagram of a current-sharing backlight drive system and a current-sequence backlight drive system with a linear voltage regulator. The current-collecting backlight driving system with a linear voltage regulator supplies power to a plurality of groups of LED strings through an external AC power source through AC/DC conversion to provide backlighting applications. The current sharing backlight driving system comprises an EMI filter 10, a rectifier 20, a power factor corrector 30, an isolated DC/DC converter 40, and a plurality of LED strings 60 (60_1~60_N). And a plurality of linear voltage regulators 50 (1 inear r egu 1 at〇r ) (5 0_ 1 ~ 5 0_N ). The current sharing backlight drive system further includes a constant current/constant voltage compensator 70, an optical coupling isolator 80, and a controller 90. [0016] The EMI filter 10 is electrically connected to the AC power source Vs to eliminate noise of the AC power source Vs and prevent interference of conductive electromagnetic noise. The rectifier 20 is electrically connected to the EMI filter 10 to convert the output AC power of the EMI filter 10 into a DC power source. The power factor corrector 30 is electrically connected to the rectifier 20 to improve the power factor of the converted DC power source. The isolated DC/DC converter 40 mainly includes a plurality of power switches (not shown) and a main transformer (not shown). The isolated DC/DC converter 40 is electrically coupled to the power factor corrector 30 as an energy conversion between the primary side input and the secondary side output of the primary transformer to provide different DC voltage levels. The isolated DC/DC converter 40 can be a flyback converter, a forward converter, a push-pull converter, and a half bridge form. No. A0101 Page 8 of 24 M391707 (half-bridge) converter or a full-bridge converter.
[0017] 每一該些發光二極體燈串60_h60_N係由複數個發光二 極體（未標示）串聯組成，該些發光二極體燈串60係為並 聯電性連接，並電性連接該隔離式DC/DC轉換器40。其中 該些線性電壓調整器50之數量係可以與該些發光二極體 燈串60之數量相等，但不以此為限。每一該些線性電壓 調整器50_1~50_N係對應電性連接該發光二極體燈串 60_1〜60_N，以細微地調整每一該些發光二極體燈串 60_卜60_N具有相同電壓或電流。值得一提，當該均流 式背光源驅動系統開始動作（啟動）時，該隔離式DC/DC轉 換器40逐漸地增加其輸出電麈，當該隔離式DC/DC轉換器 40所提供之輸出電壓未達到該些發光二極體燈串60之門 檻電壓，則該些發光二極體燈串60係以定電壓 (constant voltage)控制。舉例說明：若每一該些發 V ' : i ' . 光二極體燈串60_1~60_1^之:順偏電壓介於100伏特~120 1，- f -5 ： /[0017] Each of the light-emitting diode strings 60_h60_N is composed of a plurality of light-emitting diodes (not labeled) connected in series, and the light-emitting diode strings 60 are electrically connected in parallel and electrically connected to the light-emitting diodes 60. Isolated DC/DC converter 40. The number of the linear voltage regulators 50 may be equal to the number of the LED strings 60, but not limited thereto. Each of the linear voltage regulators 50_1~50_N is electrically connected to the LED arrays 60_1~60_N to finely adjust each of the LED strings 60_b 60_N to have the same voltage or current. . It is worth mentioning that when the current sharing backlight driving system starts to operate (start), the isolated DC/DC converter 40 gradually increases its output power when the isolated DC/DC converter 40 provides When the output voltage does not reach the threshold voltage of the light-emitting diode strings 60, the light-emitting diode strings 60 are controlled by a constant voltage. For example: if each of these sends V ' : i ' . Light diode string 60_1~60_1^: the forward voltage is between 100 volts ~ 120 1, - f -5 : /
伏特之間，因此，若當該Rfr雜gDC/DC轉換器40所提供之 輸出電壓未達到該些發光二極體燈串60之門檻電壓（即為 120伏特），則該些發光二極體燈串60係以定電壓控制。 甚至於，若有任何一該發光二極體燈串60發生故障（異常 )而無法導通，則該些發光二極體燈串60係仍會以定電壓 控制。反之，當該隔離式DC/DC轉換器40提供之輸出電壓 達到該些發光二極體燈串60之門檻電壓，則該些發光二 極體燈串係以定電流（constant current)控制。 [0018] 該定電流/定電壓補償器70係電性連接該些發光二極體燈 表單编號A0101 第9頁/共24頁 M391707 串60與該些線性電壓調整器50，以偵測每一該些發光二 極體燈串60_h60_N之電壓與電流，以提供定電壓或定 電流之補償，使每一該些發光二極體燈串60_J〜60_N* 別具有相同電壓或電流。該光耦合隔離器80係電性連接 該定電流/定電壓補償器70，以接收該定電流/定電壓補 償器70所輸出之電壓或電流信號，並傳送該電壓或電流 信號至另一隔離側，以達成電路隔離效果。該控制器90 係電性耦接該光耦合隔離器80，以接收由該光耦合隔離 器80所傳送之電壓或電流信號，以控制該功率因數校正 器30與該隔離式DC/DC轉換器40。 [0019] 此外，該些線性電壓調整器5 0與該定電流/定電壓補償器 70係分別接收一外部PWM調光信號（未標示），以控制該些 線性電壓調整器50導通（turn-on)與關閉（turn-off)， 同時控制隔離轉換器之輸出，而對該些發光二極體燈串 60進行調光之控制。其中，該PWM調光信號（配合參見第 五圖B)係由一微控制器（microcontroller^未圖示）或 一 PWM調光信號產生電路（未圖示）提供，其為一低頻（約 100赫茲〜500赫茲）方波信號。 [0020] 請參見第四圖，係為本創作定電流/定電壓補償器之較佳 實施例之電路圖。如圖所示，該定電流/定電壓補償器70 係主要包含一定電壓補償電路702、一定電流補償電路 704、一穩壓電路706以及一保護電路708。其中，該定 電壓補償電路702與該定電流補償電路704係分別由一運 算放大器與一電阻電容網路所組成。該穩壓電路70 6係由 一 TL431穩壓器與一電阻電容網路所組成。該穩壓電路 表單編號A0101 第10頁/共24頁 M391707 706係分別提供該定電壓補償電路702與該定電流補償電 路704所需之一第一參考電壓Vrefl與一第二參考電壓 Vref2。該PWM調光信號係透過該保護電路708而被該定 電流/定電壓補償器70所接收。Between volts, therefore, if the output voltage provided by the Rfr hybrid gDC/DC converter 40 does not reach the threshold voltage of the LED strings 60 (ie, 120 volts), the LEDs are The string 60 is controlled at a constant voltage. Even if any of the light-emitting diode strings 60 fails (abnormally) and cannot be turned on, the light-emitting diode strings 60 are still controlled at a constant voltage. Conversely, when the output voltage provided by the isolated DC/DC converter 40 reaches the threshold voltage of the LED strings 60, the LED strings are controlled by a constant current. [0018] The constant current/constant voltage compensator 70 is electrically connected to the light emitting diode lamp form number A0101, page 9 / 24 pages M391707 string 60 and the linear voltage regulators 50 to detect each The voltage and current of the LED strings 60_h60_N are used to provide a constant voltage or a constant current compensation so that each of the LED strings 60_J~60_N* has the same voltage or current. The optically coupled isolator 80 is electrically connected to the constant current/constant voltage compensator 70 to receive the voltage or current signal output by the constant current/constant voltage compensator 70, and transmit the voltage or current signal to another isolation. Side to achieve circuit isolation. The controller 90 is electrically coupled to the optically coupled isolator 80 to receive a voltage or current signal transmitted by the optical coupling isolator 80 to control the power factor corrector 30 and the isolated DC/DC converter. 40. [0019] In addition, the linear voltage regulators 50 and the constant current/constant voltage compensator 70 respectively receive an external PWM dimming signal (not labeled) to control the linear voltage regulators 50 to be turned on (turn- On) and turn-off, while controlling the output of the isolated converter, and dimming the light-emitting diode strings 60. The PWM dimming signal (refer to FIG. 5B) is provided by a microcontroller (not shown) or a PWM dimming signal generating circuit (not shown), which is a low frequency (about 100). Hertz ~ 500 Hz) square wave signal. [0020] Referring to the fourth figure, it is a circuit diagram of a preferred embodiment of the present invention for a constant current/constant voltage compensator. As shown, the constant current/constant voltage compensator 70 mainly includes a certain voltage compensation circuit 702, a constant current compensation circuit 704, a voltage stabilization circuit 706, and a protection circuit 708. The constant voltage compensation circuit 702 and the constant current compensation circuit 704 are respectively composed of an operational amplifier and a resistor-capacitor network. The voltage stabilizing circuit 70 6 is composed of a TL431 voltage regulator and a resistor-capacitor network. The voltage stabilizing circuit Form No. A0101 Page 10 of 24 M391707 706 provides one of the first reference voltage Vref1 and a second reference voltage Vref2 required by the constant voltage compensation circuit 702 and the constant current compensation circuit 704, respectively. The PWM dimming signal is received by the constant current/constant voltage compensator 70 through the protection circuit 708.
[0021] 對該些發光二極體燈串60進行回授控制時，透過回授該 些發光二極體燈串60之輸出電壓Vout，利用該定電壓補 償電路702之一定電壓比較器Uv，與上述之該第一參考電 壓Vrefl進行比較。當該第一參考電壓Vrefl大於該輸出 電壓Vout時（即該定電壓比較器l)v之非反相端電壓大於反 相端電壓），該定電壓比較器Uv輸出為正，使得一串接二 極體Dv逆偏截止，因此該光離弟80不動作，相對 Γ ; .[0021] When the feedback control of the light-emitting diode strings 60 is performed, the output voltage Vout of the light-emitting diode strings 60 is fed back, and the constant voltage comparator Uv of the constant voltage compensation circuit 702 is used. The first reference voltage Vref1 is compared with the above. When the first reference voltage Vref1 is greater than the output voltage Vout (ie, the voltage of the non-inverting terminal of the constant voltage comparator l)v is greater than the voltage of the inverting terminal), the output of the constant voltage comparator Uv is positive, so that a series connection The diode Dv reverses the cutoff, so the light does not move from the younger brother 80, which is relatively embarrassing.
地該光耦合隔離器80之一次树則拳產生感應電流。此時 ，該PWM調光信號之責任週期（duty cycle)增加，使得 該些發光二極體燈串60之外加電壓（即該隔離式DC/DC轉 換器之輸出電壓）逐漸增大。當荜外加電壓尚未達到其順 向導通電壓（forward voltage)時，則該些發光二極體 燈串60採以定電壓操作模式(.constant vol tage, CV) : ；r r - [0022] 一旦該些發光二極體燈串60之外加電壓逐漸增大，流經 該些發光二極體燈串60之電流逐漸增大，因此，透過偵 測並回授串聯於該些發光二極體燈串60之電阻上之跨壓 Vres，利用該定電流補償電路704之一定電流比較器Uc ，與上述之該第二參考電壓Vrefl進行比較。當該第二參 考電壓Vref 2小於該電阻上之跨壓Vres時（即該定電流比 較器Uc之非反相端電壓小於反相端電壓），該定電流比較 表單編號A0101 第11頁/共24頁 M391707 器Uc輸出為負，使得一串接二極體Dc順偏導通，因此該 光耦合隔離器80動作，相對地該光耦合隔離器80之一次 側則產生感應電流。當該外加電壓達到該些發光二極體 燈串60之順向導通電壓時，則該些發光二極體燈串60進 入定電流操作模式（constant current，CC)。 [0023] 惟，為了維持該些發光二極體燈串60之定電流操作，並 抑制該些發光二極體燈串60之外加電壓持續增大，亦即 ，當該PWM調光信號之責任週期（duty cycle)足夠大到 能維持定電流操作時，此時，該些發光二極體燈串60之 輸出電壓Vout大於該第一參考電壓Vrefl(即該定電壓比 較器Uv之反相端電壓大於非反相端電壓），該定電壓比較 器Uv輸出為負，使得該串接二極體Dv順偏通通，因此該 光耦合隔離器80動作，相對地該光耦合隔離器80之一次 側則產生感應電流。此時，該PWM調光信號之責任週期 (duty cycle)減小。如此，該定電流/定電壓補償器70 之操作將進入重複之回授調整。另外，該保護電路708係 用以防止在調光控制過程中，因高低準位轉態時所造成 瞬間電流增大之抑制。 [0024] 值得一提，請參見第五圖A與第五圖B，係分別為習知定 電流/定電壓補償器控制之波形圖以及本創作定電流/定 電壓補償器具有適應性控制之波形圖。在習知之調光控 制技術中，在高亮度調光（高責任週期）控制或在低亮度 調光（低責任週期）時，該些發光二極體燈串60A之輸出電 壓Vout分別受一上臨界電壓Vth與一下臨界電壓Vpri所 控制。由第五圖A可明顯看出，所提供該PWM調光信號之 表單编號A0101 第12頁/共24頁 導通時間Ton係為當該輸出電壓Vout由該下臨界電壓 Vpri上升至該略大於該上臨界電壓Vth所需之時間；同樣 地，該截止時間Toff係為當該輸出電壓Vout由略大於該 上臨界電壓Vth下降至該下臨界電壓Vpri所需之時間。 [0025] 然而，在本創作所提出之該定電流/定電壓補償器具有適 應性控制技術，請參見第五圖B，可明顯看出，在高亮度 調光（高責任週期）控制時，該輸出電壓Vout係被控制在 高準位，所提供該PWM調光信號之導通時間Ton係為當該 輸出電壓Vout由該略低於該上臨界電壓Vth上升至該略大 於該上臨界電壓Vth所需之時間；同樣地，該截止時間 Toff係為當該輸出電壓Vou t由略大於·該上臨界電壓Vth 下降至略小於該上臨界電壓Vth所需之時間.。此外，在低 亮度調光（低責任週期）控制時，該輸出電壓Vout係被控 制在低準位，亦即該輸出電壓Vout可受控於低於該下臨 界電壓Vpri。如此，當該PWM調光信號為高亮度調光時， 該輸出電壓係被控制在高準位，可提供該PWM調光信號之 快速響應，同時降低電壓應力；當該PWM調光信號為低亮 度調光時，該輸出電壓係被控制在低準位，可減少控制 迴路之功率損耗。 [0026] 簡而言之，本創作利用該些線性電壓調整器50取代習知 背光源驅動系統所使用之該些非隔離式DC/DC轉換器 50A(參見第一圖）。藉此，利用該些線性電壓調整器50調 整該些發光二極體燈串60因不同支路阻抗，所造成之電 壓與電流之差異，進而提供均流控制，提高該些發光二 極體燈串60之電流平衡能力，而提高發光效率並維持背 表單編號A0101 第13頁/共24頁 M391707 光照明輸出免度之均勻度。此外，由於該些線性電壓調 整器50取代該些非隔離式DC/DC轉換器50A之使用，依不 同之DC/DC轉換器電路結構（topology)，而能以降低該 些非隔離式DC/DC轉換器50A之使用數量與成本達 50%~90%。並且，透過具有適應性控制之該定電流/定電 壓補償器70，可在高亮度調光與低亮度調光時，分別控 制該輸出電壓Vout在高準位與低準位，以提供該ρψΜ調光 信號之快速響應並且減少控制迴路之功率損耗。 [0027] 惟’以上所述，僅為本創作較佳具體實施例之詳細說明 與圖式，惟本創作之特徵並不侷限於此，並非用以限制 本創作，本創作之所有範圍應以卞述之申請專利範圍為 準’凡合於本創作申請專利範面之精神與其類似變化之 實施例，皆應包含於本創作之範疇令，任何熟悉該項技 藝者在本創作之領域内，可輕易思及之變化或修飾皆可 涵蓋在以下本案之專利範圍。 【圖式簡單說明】 [0028] [0029] [0030] [0031] [0032] 第一圖係習知背光源驅動系滅之電路方塊圖； 第二圖係本創作均流式背光源驅動系統之電路方塊圖； 第三圖係本創作具有線性電壓調整器之均流式背光源驅 動系統之電路方塊圖； 第四圖係本創作定電流/定電壓補償器之較佳實施例之電 路圖； 第五圖A係習知定電流/定電壓補償器控制之波形圖；及 表單編號A0101 第14頁/共24頁 M391707The first tree of the optically coupled isolator 80 generates an induced current. At this time, the duty cycle of the PWM dimming signal is increased, so that the applied voltage of the LED strings 60 (i.e., the output voltage of the isolated DC/DC converter) is gradually increased. When the applied voltage has not reached its forward voltage, the light-emitting diode strings 60 are subjected to a constant voltage operation mode (.constant vol tage, CV): ; rr - [0022] The applied voltage of the LED array 60 is gradually increased, and the current flowing through the LED strings 60 is gradually increased. Therefore, the detection and feedback are performed in series with the LED strings. The voltage across the resistor Vres of 60 is compared with the second reference voltage Vref1 described above by a certain current comparator Uc of the constant current compensation circuit 704. When the second reference voltage Vref 2 is less than the voltage across the resistor Vres (ie, the voltage of the non-inverting terminal of the constant current comparator Uc is less than the voltage of the inverting terminal), the constant current comparison form number A0101 page 11 / total On page 24, the M391707 Uc output is negative, so that a series of diodes Dc are turned on, so that the optical coupling isolator 80 operates, and the primary side of the optical coupling isolator 80 generates an induced current. When the applied voltage reaches the forward voltage of the light-emitting diode strings 60, the light-emitting diode strings 60 enter a constant current (CC) mode. [0023] However, in order to maintain the constant current operation of the light-emitting diode strings 60, and suppress the voltages of the light-emitting diode strings 60 from increasing continuously, that is, when the PWM dimming signal is responsible When the duty cycle is large enough to maintain the constant current operation, the output voltage Vout of the LED strings 60 is greater than the first reference voltage Vref1 (ie, the inverting terminal of the constant voltage comparator Uv) The voltage is greater than the non-inverting terminal voltage, and the output of the constant voltage comparator Uv is negative, so that the series diode Dv is normally turned on, so the optical coupling isolator 80 operates, and the optical coupling isolator 80 is relatively The side generates an induced current. At this time, the duty cycle of the PWM dimming signal is reduced. As such, operation of the constant current/constant voltage compensator 70 will enter repeated feedback adjustments. In addition, the protection circuit 708 is used to prevent the suppression of the instantaneous current increase caused by the high and low level transitions during the dimming control. [0024] It is worth mentioning, please refer to the fifth figure A and the fifth figure B, which are waveform diagrams of the conventional constant current/fixed voltage compensator control and the adaptive control of the current constant current/fixed voltage compensator. Waveform diagram. In the conventional dimming control technology, in the high-brightness dimming (high duty cycle) control or in the low-brightness dimming (low duty cycle), the output voltages Vout of the LED strings 60A are respectively subjected to an upper limit. The threshold voltage Vth is controlled by the lower threshold voltage Vpri. As is apparent from the fifth diagram A, the form number A0101 of the PWM dimming signal is provided, and the on-time Ton is when the output voltage Vout rises from the lower threshold voltage Vpri to be slightly larger than The time required for the upper threshold voltage Vth; likewise, the off time Toff is the time required for the output voltage Vout to fall slightly above the upper threshold voltage Vth to the lower threshold voltage Vpri. [0025] However, the constant current/constant voltage compensator proposed in the present application has adaptive control technology, please refer to FIG. 5B, and it is apparent that during high-brightness dimming (high duty cycle) control, The output voltage Vout is controlled at a high level, and the on-time Ton of the PWM dimming signal is provided when the output voltage Vout rises slightly below the upper threshold voltage Vth to be slightly larger than the upper threshold voltage Vth. The required time; likewise, the off time Toff is the time required for the output voltage Vou t to decrease slightly from the upper threshold voltage Vth to be slightly smaller than the upper threshold voltage Vth. Moreover, during low brightness dimming (low duty cycle) control, the output voltage Vout is controlled at a low level, i.e., the output voltage Vout can be controlled below the lower critical voltage Vpri. Thus, when the PWM dimming signal is high-brightness dimming, the output voltage is controlled at a high level to provide a fast response of the PWM dimming signal while reducing voltage stress; when the PWM dimming signal is low When the brightness is dimmed, the output voltage is controlled at a low level, which reduces the power loss of the control loop. In short, the present invention utilizes the linear voltage regulators 50 to replace the non-isolated DC/DC converters 50A used in conventional backlight drive systems (see the first figure). Thereby, the linear voltage regulators 50 are used to adjust the difference between the voltage and the current caused by the different branch impedances of the light-emitting diode strings 60, thereby providing current sharing control and improving the light-emitting diode lamps. String 60's current balance capability, while improving luminous efficiency and maintaining the uniformity of the back-form number A0101 page 13 / 24 pages M391707 light illumination output. In addition, since the linear voltage regulators 50 replace the use of the non-isolated DC/DC converters 50A, depending on the DC/DC converter circuit topology, the non-isolated DC/ The number and cost of the DC converter 50A is 50% to 90%. Moreover, through the constant current/constant voltage compensator 70 with adaptive control, the output voltage Vout can be respectively controlled at a high level and a low level during high-brightness dimming and low-brightness dimming to provide the ρψΜ. The fast response of the dimming signal and reducing the power loss of the control loop. [0027] However, the above description is only for the detailed description and drawings of the preferred embodiments of the present invention, but the features of the present invention are not limited thereto, and are not intended to limit the creation, and all the scope of the creation should be The scope of the patent application is as follows: the embodiment of the patent application and the similar changes in the scope of this patent application should be included in the scope of this creation. Anyone familiar with the artist can easily use it in the field of creation. Any changes or modifications considered may be covered by the patents in this case below. [0028] [0032] [0032] The first figure is a block diagram of a conventional backlight driving system; the second picture is a current sharing type backlight driving system The block diagram of the circuit; the third diagram is a circuit block diagram of the current-sharing backlight drive system with linear voltage regulator; the fourth diagram is a circuit diagram of a preferred embodiment of the present constant current/fixed voltage compensator; Figure 5 is a waveform diagram of the conventional constant current/constant voltage compensator control; and form number A0101 Page 14 of 24 M391707
[0033] 第五圖B係本創作定電流/定電壓補償器具有適應性控制 之波形圖。 【主要元件符號說明】 [0034] 〔習知技術〕 [0035] Vs 交流電源 [0036] 10A EM I濾波器 [0037] 20A 整流器 [0038] 30A 功率因數校正器 [0039] 40A 隔離式DC/DC轉換器 [0040] 50A 非隔離式DC/DC轉換器 [0041] 60A 發光二極體燈串 [0042] 〔本創作〕 [0043] Vs 交流電源 [0044] 10 EMI濾波器 [0045] 20 整流器 [0046] 30 功率因數校正器 [0047] 40 隔離式DC/DC轉換器 [0048] 50 線性電壓調整器 [0049] 60 發光二極體燈串 [0050] 70 定電流/定電壓補償器 表單編號A0101 第15頁/共24頁 M391707 [0051] 702 定電壓補償電路 [0052] 704 定電流補償電路 [0053] 706 穩壓電路706 [0054] 708 保護電路708 [0055] 80 光耦合隔離器 [0056] 90 控制器 [0057] Vrefl第一參考電壓 [0058] Vref2第二參考電壓 [0059] Vout輸出電壓 [0060] Vres電阻跨壓 [0061] Dv 二極體 [0062] Dc 二極體 [0063] Uv 定電壓比較器 [0064] Uc 定電流比較器 [0065] Vth 上臨界電壓 [0066] Vpri下臨界電壓 [0067] Ton 導通時間 [0068] Toff截止時間 表單編號A0101 第16頁/共24頁[0033] FIG. 5B is a waveform diagram of the adaptive current/constant voltage compensator with adaptive control. [Main Component Symbol Description] [0010] Vs AC Power Supply [0036] 10A EM I Filter [0037] 20A Rectifier [0038] 30A Power Factor Corrector [0039] 40A Isolated DC/DC Converter [0040] 50A Non-Isolated DC/DC Converter [0041] 60A LED Diode String [0042] [This Creation] [0043] Vs AC Power [0044] 10 EMI Filter [0045] 20 Rectifier [ 0046] 30 Power Factor Corrector [0047] 40 Isolated DC/DC Converter [0048] 50 Linear Voltage Regulator [0049] 60 LED String Light [0050] 70 Constant Current / Constant Voltage Compensator Form No. A0101 Page 15 of 24 M391707 [0051] 702 Constant Voltage Compensation Circuit [0052] 704 Constant Current Compensation Circuit [0053] 706 Voltage Regulation Circuit 706 [0054] 708 Protection Circuit 708 [0055] 80 Optically Coupled Isolator [0056] 90 Controller [0057] Vrefl first reference voltage [0058] Vref2 second reference voltage [0059] Vout output voltage [0060] Vres resistance across voltage [0061] Dv diode [0062] Dc diode [0063] Uv Constant Voltage Comparator [0064] Uc Constant Current Comparator [0065] Vth Upper Critical Voltage [0066] Vpri Lower Threshold [0067] Ton On Time [0068] Toff Cutoff Time Form No. A0101 Page 16 of 24