1259034 14807twf.doc/g 九、發明說明： 【發明所屬之技術領域】 本毛月疋有關於-種螢光燈驅動裝置及方法，且特別是有 關於一種液晶顯示震置所使用之螢光燈驅動裝置及方法。 【先前技術】 、隨著而科技之發展，視訊或影像裝置已經成為一般曰常生 活中常見的產品。在這些視訊或影像裝置中，顯示器是一個不 可或缺的構件’使用者可由顯示器讀取資訊，或進而控制裝置 的運作。其中，液晶顯示器crystal display，LCD)以其體 和小、耗電低、低電壓驅動以及應用範圍廣等優點，有逐漸取 代傳統陰極射線管(cath〇de ray㈣，⑽)顯示器的趨勢。 液晶顯示器的操作原理係利用液晶材料的旋光性(叩咖 acuity)和電絲特性，麵邱像和文字資訊的-種平面顯 :器、。液晶材料本身並不具備發光的特性，因此需要一外加的 背光源及其驅動電路作為辅助，而常用的背光源為營光燈，例 > 陰極螢光燈(c〇ld cath〇de f[u〇rescent iamp，ccfl)。 在白知的螢光燈驅動電路中，由於驅動螢光燈的電流波形 之對％性會影響到螢光燈的壽命，因此，大部分的設計採用全 橋式的直机/父流轉換電路來驅動螢光燈。而且，全橋式直流/ 轉換電路_般需配合變壓器’將輸人的直流電壓轉換成高 壓的交流電壓’關練光燈，這種直流/交流轉換的驅動電 路般亦稱為變流器(inverter)。為了使螢光燈的光源穩定，並 1259034 14807twf.doc/g 且党度不會隨著輸入電壓的變動而改變，因此變流器在設計上 大都搭配著負回授控制電路，以穩定營光燈的操作電流。 Θ係、、、a示4知的種全橋式螢光燈驅動電路。請參照圖 1，此全橋式螢光燈驅動電路包括直流電壓源11〇、橋式直流/ 交流轉換器120、變壓器13〇、螢光燈14〇、電流偵测器15〇、 電壓偵測器以及回授控制單元170。其中，橋式直流/交流 轉換器120包含四個開關121、123、125以及127，而回授控 >制單元170包含誤差放大器及控制電路17卜驅動單元以 及脈波寬度調_ 175，此外，螢光燈14〇係配置於液晶顯示 裝置145中。 此習知的螢光燈驅動電路之操作方式，係以橋式直流/交 流轉換裔120中開關121與127為一組，開關丨23與125為另 一組，兩組根據驅動單元173提供的脈波訊號輪流地導通，將 直流電壓源110所輸出的直流電壓轉換成高頻的交流方波輸 >出，再利用變壓器Π0與電容c卜C2進行升壓與濾波，最後 將南頻的父流方波轉換成高頻高壓的交流弦波，以驅動螢光燈 140 ° 然後，利用電流偵測器150取得螢光燈14〇之電流訊號， 以及利用電壓偵測器160取得變壓器13〇送入螢光燈14〇之電 壓訊號，最後，由回授控制單元根據這兩個訊號進行負回授控 制。由於螢光燈的亮度是由通過燈管的電流所決定，因此在誤 7 1259034 14807twf.doc/g 差放大器及控制電路171判斷螢光燈140的狀況後，藉著脈波 寬度調變器175以及驅動單元173調整橋式直流/交流轉換器 120之輸出的脈波寬度，可以在變壓器13〇 一次側得到不同脈 波寬度之電壓訊號，這樣相當於調整螢光燈通過電流之時間， 以達到穩定及調整螢光燈亮度的目的。 圖2A、2B係繪示習知的一種全橋式螢光燈驅動電路之變 震為一次側電壓訊號。如圖2A、2B所示，pi點為橋式直流/ 交流轉換器120中開關121與123之耦接點，而？2點則為開 關125與127之耦接點，因此，變壓器13〇 一次側之電壓訊號 即為Η與P2兩點之電壓差。所以，藉著脈波寬度調變器175 以及驅動單元173，調整橋式直流/交流轉換器12〇在 兩=的電壓之脈波寬度，可以在變壓器13G—次側得到不同脈 波寬度的電壓訊號’如圖2A中變壓器一次側之電壓訊號與圖 :中變次側之電壓訊號減，兩者具有相同的最高電 ^位V卜但是不同的脈波寬度。利用回授機制以不同脈波 j的電壓訊號職螢光燈，即可達義定及調錢光燈亮度 的目的。 【發明内容】 本發明的目的就是在提供 壓调節器調整提供給變壓器一 一種螢光燈驅動裝置，係利用電 次侧的交流電壓，藉由螢光燈電 1259034 14807twf.doc/g .............-------------------------------------------------__________ — 為’形成一個負回授電路，用以達 目的。 流的回授再去控制電壓調節 到穩定及調整螢光燈亮度的 〜本發明的再-目的就是在提供—種榮光燈驅動方法，其調 即螢光k宂度的方法係提供—交流訊號驅動螢光燈，再债測勞 級的電流’姻回授機制調整驅動螢光燈的交流訊號，用以 達到穩定及調整螢光燈亮度的目的。 鲁 *發明提出一種螢光燈驅動裝置，包括直流電壓源、電壓 調節器、橋式直流/交流難器、變壓器、螢紐、電流偵測 器以及回授控制單元。直流電壓源輸出第一直流電壓到電壓調 節器，而電壓調節器則根據從回授控制單元接收的回授控制訊 就-周整第-直流電壓，然後輸出第二直流電屋到橋式直流/ 交流轉換器。再來，橋式直流/交流轉換器根據從回授控制單 疋接收的驅動訊號，將第二直流電壓轉換成第一交流電壓，其 鲁 中驅動訊號皆為固定脈寬之脈波串，因此第一交流電壓亦具有 ®定脈寬’不過’第-交流電壓之電壓準㈣受第二直流電壓 之電壓準位所控制。換句話說，就是利用電壓調節器輸出調整 過的電源電壓（即第二直流電壓），再經過橋式直流/交流轉換器 可以得到具有固定脈寬的第一交流電壓，由於調整第二直流電 壓相當於調整第一交流電壓的電壓準位，藉不同電壓準位的第 一交流電壓來調整及穩定螢光燈亮度。 9 1259034 14807twf.doc/g '' —-......—一 _ 不過’需要顏^之—賴接收第—交流電壓，用以升壓 以及濾波，再從變壓器之二次側輸出第二交流電壓到營光燈之 第接著電流债測器從螢光燈之第二端取得通過該榮光燈 之電流訊號’並輸入該電流訊號到回授控制單丨，回授控制單 元則根據這個電流訊號輸出回授控制訊號給電壓調節器，形成 -個負回授控制的迴路。此外，回授控财元提供固定脈寬的 驅動訊號給橋式直流/交流轉換器，用以驅動橋式直流/交流轉 換為將將第二直流電壓轉換成具固定脈寬的第—交流電壓。 依照本發明的較佳實施例所述之螢光燈驅動裝置，其中電 壓調節器可叹線性電壓調節器，亦可以是切換式電壓^ 器m錢/交鱗換料以是全橋式錢/交祕換器， 此外，螢光燈可以是冷陰極螢光燈。 依照本發明的較佳實施例所述之螢光燈驅動裝置，其中回 私授控制單元包括誤差放大器及控制電路、驅動單元。此誤差放 大器及控制電路，用以接收電流侧器所偵測的榮光燈之電流 訊號，並輸出回授控制訊號給電壓調節器。驅動單元則是用以 輸出驅動訊號給橋式直流/交流轉換器。 依照本發明的較佳實施例所述之螢光燈驅動裝置，更包括 電壓债測器。此電壓_器墟變壓器之二次侧以及驅動單 元，用以偵測第二交流電壓，並利用第二交流電墨控制驅動單 元’達到保護螢光燈驅動裝置的目的。 1259034 14807twf.doc/g 依照本發明的較佳實施例所述之螢光燈驅動裝置，其中回 授控制單元更包括保遵單元。此保護單元轉接於電壓彳貞測哭、 電流制ϋ以及驅動單元之間，係根據第二交流電壓以及營光 燈之電流訊號控制驅動單元。 本發明提出-種螢光燈驅動方法，包括：以交流訊號驅動 螢光燈，其中交流訊號具有固定脈寬；偵測螢光燈之電流；根 據螢光垃之兒流，產生回授訊號；以及利用回授訊號，調整用 > 以驅動螢光燈之交流訊號的電壓準位。 為讓本發明之上述和其他目的、特徵和優點能更明顯易 懂，下文特舉較佳實施例，並配合所附圖式，作詳細說明如下。 【實施方式】 為使本發明之實施說明能更加清楚，以下橋式直流/交流 轉換器以全橋式直流/交流轉換器為例，並且全橋式直流/交流 .轉換器中之開關以由Ν型金氧半(NM〇s)電晶體組成的開關為 例’凡熟悉此藝者應可輕易類推至其他橋式直流/交流轉換器 和開關。 圖3係依照本發明較佳實施例所繪示之螢光燈驅動電 路。請參照目3，此螢光燈驅動電路包括直流電壓源、31〇、橋 式直流/交流轉換器320、變壓器33〇、$光燈34〇、電流债; 器350、t壓偵測器36〇、回授控制單元37〇卩及電壓調節器 380。其中，橋式直流/交流轉換器32〇包含四個開關m'Μ]、 11 1259034 14807twf.doc/g 325以及327，回授控制單元370包含誤差放大器及控制電路 371、驅動單元373以及保護單元377，而螢光燈340係配置 於液晶顯示裝置345中。另外，電壓調節器380可以是線性電 壓調節器（linear regulator)，亦可以是切換式電壓調節器（switch power regulator) ° 橋式直流/交流轉換器320可以將開關分成兩組，即開關 321與327 —組，開關323與325為另一組。兩組開關根據驅 I 動早元373提供固定脈見之驅動訊號輪流地導通，例如：開關 321與327皆導通時，開關323與325則皆不導通；反之，開 關321與327皆不導通時，開關323與325則皆導通，如此一 .來，電壓調節器380輸出的第二直流電壓經過橋式直流/交流 轉換器320會變成第一交流電壓，係一交流方波。第一交流電 壓在經過變壓器330與電容C3、C4進行升壓與濾波後，變成 第一父流電壓’係為一高壓的交流弦波，用以驅動螢光燈34〇。 .然後，利用電流偵測器350取得螢光燈34〇之電流訊號， 由回授控制單元巾的誤差放大n及控制電路371根據這個電 流訊號，送出迴授控制訊號給電壓調節器38〇進行負回授控 制’以達到穩定及調整營光燈亮度的目的。至於回授控制單元 中的驅動單元373部分，因為只需要給橋式直流/交流轉換器 320固定脈寬的驅動訊號’因此，不必如圖i習知技術中需要 用到脈波寬度調變器173。但是，為了保護勞光燈驅動裝置， 12 1259034 14807twf.doc/g 377 , ^ 360 ^#，li 動螢光燈340的第二交流電壓，以及利用電流偵測器35〇測得 流經螢光燈340的電流訊號，根據螢光燈34〇電壓、電流的情 形來控制驅動單元373，藉以保護螢光燈驅動裝置。 目4A、4B係依照本發日她佳實施例所繪示之榮光燈驅動 . 電路的變壓器一次側電壓訊號。如圖4A、4B所示，Q1點為 • 橋式直流/交流轉換器320中開關321與323之耗接點，而Q2 j則為開關325與327之|馬接點，因此，變壓器33〇 一次侧之 號(即第一交流電壓)為w與q2兩點之電壓差。所以， '著包壓凋節态380，調整橋式直流/交流轉換器32〇在以、 ^兩點的電壓之電壓準位，可以在變壓器33〇 一次側得到不 ^ %左準位的第一交流電壓，如圖2A中變壓器-次側之第-^流電壓與圖2B中變壓器一次側之第一交流電壓相比，兩者 • 1相同的脈波寬度，但是不同的電壓準位V卜V2。利用回 ^機制以不同電壓準位之第一交流電壓經過變壓器33〇升壓 1去_螢光燈’即可達到穩定及調整螢光燈亮度的目的。 圖5係依照本發明所繪示之螢光燈驅動方法的流程圖。首 先’在步驟SSin ^ iU ’以具有固定脈寬交流訊號驅動螢光燈，使 发光燈發光。；^ ^ . 安者’在步驟S520偵測螢光燈之電流，並且在 S53D 士P i会 才乂據此螢光燈電流產生回授訊號。最後，在步驟S540 13 1259034 I4807twf.doc/g 利用此回授訊號回去調整原先用來驅動料 電壓準位，使得螢光燈的亮度可以穩定。 & 一综上所述，本發賴供—種螢光燈,鶴裝置及方法，係提 供交流電壓驅動螢光燈發光，再利用勞光燈的電流進行回授# 制，調整驅動螢光燈的交流電壓，用以達到穩定 _ 亮度的機制。 愛光且 雖然本發明已以較佳實施例揭露如 …、具亚非用以限定 柄月’任何熟習此技藝者’在不麟本發明之精神和範圍 内，當可作些許之更動與潤飾，因此本發明之保護 附之申請專纖者鱗。 ^視後 【圖式簡單說明】 圖1係繪不習知的一種全橋式螢光燈驅動電路。 圖2八、犯係繪示習知的一種全橋式榮光燈驅動 壓器-次側電壓訊號。 电路之交 圖3係依照本發明較佳實施例所繪示之 忠冗x且驅動電路。 圖4A、4B係依照本發明較佳實施例所绔 丛 電路的變壓次側電壓訊號。 光燈驅動 。圖5係依照本發明輯示之螢咏_方法的步驟流程 圖0 【主要元件符號說明】 14 1259034 14807twf.doc/g S510〜S540:依照本發明所繪示之螢光燈驅動方法的各個 步驟流程 110、310 :直流電壓源 120、 320 :橋式直流/交流轉換器 121、 123、125、127、321、323、325、327 :開關 130、330 :變壓器 140、340 :螢光燈 • 145、345 :液晶顯示裝置 150、350 :電流偵測器 160、360 :電壓偵測器 . 170、370 :回授控制單元 171、371 :誤差放大器及控制電路 173、373 :驅動單元 175 :脈波寬度調變器 ® 377 :保護單元 * 380 :電壓調節器1259034 14807twf.doc/g IX. Description of the Invention: [Technical Fields of the Invention] The present invention relates to a fluorescent lamp driving device and method, and more particularly to a fluorescent lamp used for a liquid crystal display. Drive device and method. [Prior Art] With the development of technology, video or video devices have become common products in common life. In these video or imaging devices, the display is an indispensable component. The user can read information from the display or, in turn, control the operation of the device. Among them, the liquid crystal display (LCD) has a tendency to gradually replace the conventional cathode ray tube (cath〇de ray (4), (10)) display with its advantages of small size, low power consumption, low voltage driving and wide application range. The operating principle of the liquid crystal display utilizes the optical rotation of the liquid crystal material and the characteristics of the wire, the surface image and the text information. The liquid crystal material itself does not have the characteristics of light emission, so an additional backlight and its driving circuit are needed as an aid, and the commonly used backlight is a camping light, for example, a cathode fluorescent lamp (c〇ld cath〇de f[ U〇rescent iamp, ccfl). In Baizhi's fluorescent lamp driving circuit, since the % of the current waveform of the driving fluorescent lamp affects the life of the fluorescent lamp, most of the designs adopt a full-bridge straight/parent conversion circuit. To drive the fluorescent light. Moreover, the full-bridge DC/conversion circuit _ is generally required to cooperate with the transformer to convert the input DC voltage into a high-voltage AC voltage. This DC/AC conversion drive circuit is also called a converter ( Inverter). In order to stabilize the light source of the fluorescent lamp, and 1259034 14807twf.doc/g and the party degree does not change with the change of the input voltage, the converter is mostly designed with a negative feedback control circuit to stabilize the camp light. The operating current of the lamp. A full-bridge fluorescent lamp driving circuit of the four types is known. Referring to FIG. 1, the full-bridge fluorescent lamp driving circuit includes a DC voltage source 11〇, a bridge DC/AC converter 120, a transformer 13〇, a fluorescent lamp 14〇, a current detector 15〇, and a voltage detection. And feedback control unit 170. The bridge DC/AC converter 120 includes four switches 121, 123, 125, and 127, and the feedback control unit 170 includes an error amplifier and a control circuit 17 and a pulse width modulation _175. The fluorescent lamp 14 is disposed in the liquid crystal display device 145. The operation mode of the conventional fluorescent lamp driving circuit is a group of switches DC and AC switches 120 and 127, and switches 丨23 and 125 are another group, and the two groups are provided according to the driving unit 173. The pulse signal is turned on in turn, converting the DC voltage outputted by the DC voltage source 110 into a high-frequency AC square wave transmission > output, and then using the transformer Π0 and the capacitor cBu C2 for boosting and filtering, and finally the south frequency The parent square wave is converted into a high frequency and high voltage AC sine wave to drive the fluorescent lamp 140 °, then the current detector 150 is used to obtain the current signal of the fluorescent lamp 14 ,, and the voltage detector 160 is used to obtain the transformer 13 〇 The voltage signal of the fluorescent lamp 14 is sent, and finally, the feedback control unit performs negative feedback control based on the two signals. Since the brightness of the fluorescent lamp is determined by the current passing through the lamp tube, after the error amplifier and control circuit 171 determines the condition of the fluorescent lamp 140 by the error 7 1259034 14807 twf.doc/g, the pulse width modulator 175 is used. And the driving unit 173 adjusts the pulse width of the output of the bridge DC/AC converter 120, and can obtain voltage signals of different pulse widths on the primary side of the transformer 13〇, which is equivalent to adjusting the time of passing the current of the fluorescent lamp to Stabilize and adjust the brightness of the fluorescent lamp. 2A and 2B are diagrams showing a variation of a conventional full-bridge fluorescent lamp driving circuit as a primary side voltage signal. As shown in FIGS. 2A and 2B, the pi point is the coupling point of the switches 121 and 123 in the bridge DC/AC converter 120, and ? 2 points are the coupling points of the switches 125 and 127. Therefore, the voltage signal of the primary side of the transformer 13 即 is the voltage difference between the two points of Η and P2. Therefore, by adjusting the pulse width of the bridge DC/AC converter 12 at two voltages by the pulse width modulator 175 and the driving unit 173, voltages of different pulse widths can be obtained on the transformer 13G-second side. The signal 'as shown in Fig. 2A, the voltage signal on the primary side of the transformer and the voltage signal on the middle side of the transformer are reduced. Both have the same highest voltage V but different pulse widths. Using the feedback mechanism to use the voltage signal of the different pulse waves, the fluorescent light can be used to achieve the purpose of adjusting the brightness of the light. SUMMARY OF THE INVENTION The object of the present invention is to provide a pressure regulator adjustment to a transformer, a fluorescent lamp driving device, which utilizes an alternating current voltage on the secondary side, by means of a fluorescent lamp 1259034 14807twf.doc/g. ............-------------------------------------- -----------__________ — To form a negative feedback circuit for the purpose. The feedback of the flow is then controlled to adjust the voltage to stabilize and adjust the brightness of the fluorescent lamp. The second objective of the present invention is to provide a method for driving a glory lamp, the method of which is to provide a method of illuminating k-degrees. Drive the fluorescent lamp, and then adjust the current signal of the fluorescent lamp to adjust and control the brightness of the fluorescent lamp. Lu* invented a fluorescent lamp driver that includes a DC voltage source, a voltage regulator, a bridge DC/AC converter, a transformer, a flashlight, a current detector, and a feedback control unit. The DC voltage source outputs the first DC voltage to the voltage regulator, and the voltage regulator controls the first DC voltage according to the feedback control received from the feedback control unit, and then outputs the second DC house to the bridge DC/ AC converter. Then, the bridge DC/AC converter converts the second DC voltage into a first AC voltage according to the driving signal received from the feedback control unit, and the driving signals of the Lu are driven by a pulse width of a fixed pulse width. The first alternating voltage also has a constant pulse width 'but 'the voltage of the first alternating current voltage (four) is controlled by the voltage level of the second direct current voltage. In other words, the voltage regulator is used to output the adjusted power supply voltage (ie, the second DC voltage), and then the bridge DC/AC converter can obtain the first AC voltage with a fixed pulse width, because the second DC voltage is adjusted. It is equivalent to adjusting the voltage level of the first AC voltage, and adjusting and stabilizing the brightness of the fluorescent lamp by the first AC voltage of different voltage levels. 9 1259034 14807twf.doc/g '' —-......—一_ However, 'requires the color ^ depends on receiving the first - AC voltage for boosting and filtering, and then outputting from the secondary side of the transformer Second, the AC voltage to the camping light, the current current detector, obtains the current signal passing through the glory light from the second end of the fluorescent lamp and inputs the current signal to the feedback control unit, and the feedback control unit according to the The current signal outputs a feedback control signal to the voltage regulator to form a negative feedback control loop. In addition, the feedback control unit provides a fixed pulse width driving signal to the bridge DC/AC converter for driving the bridge DC/AC conversion to convert the second DC voltage into a first AC voltage having a fixed pulse width. . A fluorescent lamp driving device according to a preferred embodiment of the present invention, wherein the voltage regulator is sinable linear voltage regulator, or can be a switching voltage device, m money/crossing refueling to be full bridge type money/ In addition, the fluorescent lamp can be a cold cathode fluorescent lamp. A fluorescent lamp driving apparatus according to a preferred embodiment of the present invention, wherein the feedback control unit comprises an error amplifier and a control circuit, and a driving unit. The error amplifier and the control circuit are configured to receive the current signal of the glory light detected by the current side device, and output a feedback control signal to the voltage regulator. The drive unit is used to output the drive signal to the bridge DC/AC converter. A fluorescent lamp driving apparatus according to a preferred embodiment of the present invention further includes a voltage debt detector. The secondary side of the voltage transformer and the driving unit are used to detect the second alternating voltage, and the second alternating current ink is used to control the driving unit to achieve the purpose of protecting the fluorescent lamp driving device. 1259034 14807 twf.doc/g A fluorescent lamp driving apparatus according to a preferred embodiment of the present invention, wherein the feedback control unit further comprises a compliance unit. The protection unit is connected between the voltage detection crying, the current system and the driving unit, and controls the driving unit according to the second alternating voltage and the current signal of the camping light. The invention provides a method for driving a fluorescent lamp, comprising: driving a fluorescent lamp with an alternating current signal, wherein the alternating signal has a fixed pulse width; detecting a current of the fluorescent lamp; and generating a feedback signal according to the flow of the fluorescent light; And using the feedback signal, adjusting > to drive the voltage level of the AC signal of the fluorescent lamp. The above and other objects, features and advantages of the present invention will become more <RTIgt; [Embodiment] In order to make the implementation description of the present invention clearer, the following bridge DC/AC converters are exemplified by a full-bridge DC/AC converter, and the switches in the full-bridge DC/AC converter are For example, a switch composed of a 金-type MOS transistor can be easily analogized to other bridge DC/AC converters and switches. Figure 3 is a diagram of a fluorescent lamp driving circuit in accordance with a preferred embodiment of the present invention. Please refer to item 3. The fluorescent lamp driving circuit includes a DC voltage source, a 31 〇, a bridge DC/AC converter 320, a transformer 33 〇, a light 34 〇, a current debt, a device 350, and a t-voltage detector 36.回, feedback control unit 37〇卩 and voltage regulator 380. The bridge DC/AC converter 32A includes four switches m'Μ], 11 1259034 14807twf.doc/g 325 and 327, and the feedback control unit 370 includes an error amplifier and control circuit 371, a driving unit 373, and a protection unit. 377, and the fluorescent lamp 340 is disposed in the liquid crystal display device 345. In addition, the voltage regulator 380 can be a linear regulator or a switch power regulator. The bridge DC/AC converter 320 can divide the switches into two groups, namely, the switch 321 and 327 - Group, switches 323 and 325 are another group. The two sets of switches are turned on according to the drive signal provided by the fixed pulse 370. For example, when the switches 321 and 327 are both turned on, the switches 323 and 325 are not turned on; otherwise, the switches 321 and 327 are not turned on. The switches 323 and 325 are both turned on. As a result, the second DC voltage outputted by the voltage regulator 380 passes through the bridge DC/AC converter 320 to become the first AC voltage, which is an AC square wave. After the first AC voltage is boosted and filtered by the transformer 330 and the capacitors C3 and C4, the first parent voltage is a high-voltage AC sine wave for driving the fluorescent lamp 34 〇. Then, the current detector 350 is used to obtain the current signal of the fluorescent lamp 34, and the error amplification of the feedback control unit towel and the control circuit 371 send the feedback control signal to the voltage regulator 38 according to the current signal. Negative feedback control 'to achieve the purpose of stabilizing and adjusting the brightness of the camp light. As for the portion of the driving unit 373 in the feedback control unit, since only the driving signal of the pulse width is fixed to the bridge DC/AC converter 320, it is not necessary to use the pulse width modulator as in the prior art. 173. However, in order to protect the lamp driver, 12 1259034 14807 twf.doc/g 377 , ^ 360 ^#, the second AC voltage of the fluorescent lamp 340, and the flow through the fluorescent detector 〇 The current signal of the lamp 340 controls the driving unit 373 according to the voltage and current of the fluorescent lamp 34, thereby protecting the fluorescent lamp driving device. Heads 4A, 4B are the glory light drive according to her preferred embodiment of the present day. The transformer primary side voltage signal of the circuit. As shown in FIGS. 4A and 4B, the Q1 point is the contact point of the switches 321 and 323 in the bridge DC/AC converter 320, and the Q2 j is the contact point of the switches 325 and 327. Therefore, the transformer 33〇 The number of the primary side (ie, the first alternating voltage) is the voltage difference between two points w and q2. Therefore, 'the package voltage 380 is adjusted, and the bridge DC/AC converter 32 is adjusted to the voltage level of the voltage at two points, and the left side of the transformer 33 can be obtained. The first AC voltage, as shown in Fig. 2A, is the same as the first AC voltage on the primary side of the transformer in Fig. 2B, and the same pulse width, but different voltage levels. V Bu V2. The first AC voltage with different voltage levels can be stabilized and the brightness of the fluorescent lamp can be adjusted by using the return mechanism to boost the brightness of the fluorescent lamp through the transformer 33. FIG. 5 is a flow chart of a method of driving a fluorescent lamp according to the present invention. First, in the step SSin ^ iU ', the fluorescent lamp is driven by a fixed pulse width alternating current signal to cause the light to emit light. ; ^ ^ . The security device detects the current of the fluorescent lamp in step S520, and generates a feedback signal according to the current of the fluorescent lamp at S53D. Finally, in step S540 13 1259034 I4807twf.doc/g, the feedback signal is used to adjust the voltage level originally used to drive the material so that the brightness of the fluorescent lamp can be stabilized. & In summary, the present invention provides a fluorescent lamp, a crane device and a method, which provide an AC voltage to drive a fluorescent lamp to emit light, and then use the current of the work light lamp to perform feedback control, and adjust the driving fluorescence. The AC voltage of the lamp is used to achieve a stable _ brightness mechanism. AI LIGHT and although the present invention has been disclosed in the preferred embodiments, such as the use of the Asian and African to define the stalking 'any skilled in the art', within the spirit and scope of the present invention, when some changes and refinements can be made, Therefore, the protection of the present invention is attached to the application of the special fiber scale. [After the drawing] [Fig. 1] A conventional full-bridge fluorescent lamp driving circuit is shown. Figure 2 is a full-bridge glory lamp driver-secondary voltage signal. Intersection of Circuitry Figure 3 is a diagram of a loyalty x and drive circuit in accordance with a preferred embodiment of the present invention. 4A and 4B are diagrams showing a voltage-changing secondary side voltage signal of a sinusoidal circuit in accordance with a preferred embodiment of the present invention. Light drive. 5 is a flow chart of a method for displaying a 咏 咏 method according to the present invention. [Main element symbol description] 14 1259034 14807 twf.doc/g S510~S540: steps of a fluorescent lamp driving method according to the present invention Flows 110, 310: DC voltage sources 120, 320: Bridge DC/AC converters 121, 123, 125, 127, 321, 323, 325, 327: Switches 130, 330: Transformers 140, 340: Fluorescent lamps • 145 345: liquid crystal display device 150, 350: current detector 160, 360: voltage detector. 170, 370: feedback control unit 171, 371: error amplifier and control circuit 173, 373: drive unit 175: pulse wave Width Modulator® 377: Protection Unit* 380: Voltage Regulator
Cl、C2、C3、C4 :電容 15Cl, C2, C3, C4: Capacitor 15