1358970 九、發明說明： 【發明所屬之技術領域】 為一種用於一螢光燈之電流監測系統（current monitoring system)，尤指一種具一偵測電路（detecting circuit)與一判斷電路(judging circuit)之電流監測系統。 【先前技術】 φ 今日螢光燈之運用日益普遍，為提高其安全性，並保 榮光燈系統在發生開路（open-circuited status)、短路 (short-circuited status)及跳火（arcing status)等異常狀態時， • 其零組件不致損毀’今提出一種可用於監控一螢光燈之燈 管電流的電流監測系統’以在其發生開路、短路及跳火時 將該螢光燈予以即時關斷。 前此在習知技藝中，並未針對螢光燈系統因發生跳火 狀態而引致之損毁提出預防電路或保護裝置；但若螢光燈 φ 系統處於跳火之不穩定情況，久而久之，亦將造成其零組 件之損毀，所以螢光燈系統發生跳火之不穩定情況也是應 當要積極預防因應的。 如前所述，若能提出一種監控螢光燈之燈管電流的電 流監測系統，且可分別因應其開路、短路及跳火等異常狀 態，而將該螢光燈予以即時關斷，以防止任何元件因此損 毀，同時具有相對較簡單之結構，可達成具有相對較高之 效益性與相對較低之總成本等優點，此即為本發明所亟於 6 1358970 達成之目標。 職是之故，發明人鑒於習知技術之缺失，乃思及改良 發明之意念，終能發明出本案之「螢光燈之電流監測系統 及其控制方法」。 【發明内容】 本案之主要目的在於提供一種用於一螢光燈之電流監 測系統，將該螢光燈之一燈組電流做一整流，藉由一偵測 • 電路將該經整流之電流信號轉變為一方波信號，並透過一 判斷電路以判斷該方波信號是否發生變化，以及當該方波 信號發生變化時，由該判斷電路產生一控制信號以關斷該 螢光燈。該電流監測系統可運用於監測該螢光燈發生開 路、短路及跳火等不同之異常狀態，且其電路結構相對較 簡單，故其具有一相對較佳之效益與一相對較低之總成本 等優點。 本案之又一主要目的在於提供一種用於一螢光燈之電 • 流監測系統，包含一整流器，接收該螢光燈之一燈組電流， 用以產生一經整流之正弦波週期信號，一偵測電路，接收 該經整流之正弦波週期信號，用於與一預設之高準位及一 預設之低準位比較，以產生一方波週期信號，以及一判斷 電路，接收該方波週期信號，用以產生一鋸齒波週期信號， 其中當該鋸齒波週期信號之一信號值超過一預設之判斷準 位時，該螢光燈係處於一異常狀態，此時該判斷電路將產 生一控制信號，以關斷該螢光燈。 7 1358970 根據上述之構想，該整流器係為一全波整流器。 根據上述之構想，該整流器具一輸出端，且該偵測電 路包含一比較器，具一反相端、一非反相端與一 ， 一第一電’具一第—端與一第二端，其令該帛一端耦合 於參考電壓，且该第二端耦合於該比較器之該輸出端， -第一電阻’具一第一端與一第二端，其中該第一端耦合 於该比較器之該輸出端 第二電阻，具一第一端與一第二端，其中該第 相端1358970 IX. Description of the Invention: [Technical Field] The present invention relates to a current monitoring system for a fluorescent lamp, and more particularly to a detecting circuit and a judging circuit. ) Current monitoring system. [Prior Art] φ Today's fluorescent lamps are increasingly used, to improve their safety, and to open-circuited status, short-circuited status, and arcing status. In the abnormal state, • its components are not damaged. A current monitoring system that can be used to monitor the lamp current of a fluorescent lamp is proposed to immediately turn off the fluorescent lamp when it is open, shorted and hopped. . In the prior art, there is no prevention circuit or protection device for the damage caused by the flashover state of the fluorescent lamp system; however, if the fluorescent lamp φ system is in an unstable situation of jumping fire, over time, it will also As a result of the damage of its components, the instability of the flashlight system flashover should also be actively prevented. As mentioned above, if a current monitoring system for monitoring the lamp current of a fluorescent lamp can be proposed, and the abnormal state such as open circuit, short circuit and flashover can be respectively turned off, the fluorescent lamp can be immediately turned off to prevent Any component is thus destroyed, and at the same time has a relatively simple structure, which can achieve the advantages of relatively high efficiency and relatively low total cost, which is the goal achieved by the invention in 6 1358970. As a result of the job, the inventor, in view of the lack of prior art, thought of and improved the idea of invention, and finally invented the "current monitoring system for fluorescent lamps and its control method" in this case. SUMMARY OF THE INVENTION The main object of the present invention is to provide a current monitoring system for a fluorescent lamp, the current of one of the fluorescent lamps is rectified, and the rectified current signal is detected by a detecting circuit. The signal is converted into a square wave, and is judged by a judging circuit to determine whether the square wave signal changes, and when the square wave signal changes, the determining circuit generates a control signal to turn off the fluorescent lamp. The current monitoring system can be used to monitor different abnormal states such as open circuit, short circuit and flashover of the fluorescent lamp, and the circuit structure thereof is relatively simple, so that it has a relatively good benefit and a relatively low total cost. advantage. Another main object of the present invention is to provide an electric current monitoring system for a fluorescent lamp, comprising a rectifier for receiving a lamp current of the fluorescent lamp for generating a rectified sinusoidal periodic signal, The measuring circuit receives the rectified sine wave periodic signal for comparison with a predetermined high level and a predetermined low level to generate a square wave periodic signal, and a determining circuit for receiving the square wave period a signal for generating a sawtooth periodic signal, wherein when the signal value of one of the sawtooth periodic signals exceeds a predetermined judgment level, the fluorescent lamp is in an abnormal state, and the determining circuit generates a Control signal to turn off the fluorescent light. 7 1358970 According to the above concept, the rectifier is a full-wave rectifier. According to the above concept, the rectifier device has an output end, and the detecting circuit comprises a comparator having an inverting terminal, a non-inverting terminal and a first electric device having a first end and a second end. The first end is coupled to the reference voltage, and the second end is coupled to the output end of the comparator, the first resistor has a first end and a second end, wherein the first end is coupled to a second resistor of the output of the comparator, having a first end and a second end, wherein the first end
^ π—响，丹τ琢第一 端耦合於該第二電阻之該第二端，且該第二端接地，一第 四電阻，具一第一端與一第二端’其中該第一端耦合於該 第三電阻之該第一端，且該第二端耦合於該參考電壓，以 及-第五電阻，具一第一端與一第二端，其中該第一端耦 合於該比較器反相端，且該第二端Μ合於該整流器之該輸 出端。 根據上述之構想，該判斷電路包含一正半週判斷裝 置在遠燈官電流之-正半週時接收該方波週期信號，用 以在該正半週時產线_波週期信號，—貞半週_裝 置，在該燈管電流之-貞半週時純該方波㈣信號，用 以在該負半週時產生該鑛齒波週期信號，H具 、端、-第—端與-輸出端，其中該第—端接收在該正 ，時所產生之該鋸齒波週期信號，且該第二端接收在該 “週時所產生之該鑛齒波週期信號，以及—比 反相端、一非反相端與一輪出嫂.具— 齡淮Α ^ , 輸出柒，其中該反相端接收該列 準位，該非反相仙合於該或閘之該輸出端，且該輪出 8 1358970 應 · 端用以在該異常狀態時產生該控制信號。 根據上述之構想，該正半週判斷裝置包含一充電器， 具-電流源與-電阻兩者其中之_，且接收一參考電壓， 用以產生-充電電流，一電容，具一第一端與一第二端， :、中》亥第糕接收该充電電流，用以產生該鋸齒波週期作 號’且耦合於該或閘之該第-端，而該第二端接地，1 具-第-端、-第二端與一控制端，其中該第一端麵 二於該電谷之該第一端，該第二端耦合於該電容之該第二 端，且該控制端接收該方波週期信號。 根據上述之構想，該負半週判斷裝置包含一反相器， 具-第-端與一第二端，其中該第一端接收該方波週期信 唬’一充電器，具―電流源與一電阻兩者其中之…且接 收參考電塵，用以產生一充電電流，一電容，且—第— 端與一第二端，其中該第—端接收該充電電流，用、以產生 该鋸齒波週期信號，且耦合於該或閘之該第二端，而該第 二端接地’ -開關，具一第一端、一第二端與一控制端， ςΓϊ第—輪合於該電容之該第—端，該第二端輕合於 h -今之該第二端，且該控制端耦合於該反相器該第二端。 根據上述之構想，該異常狀態係選自該螢光燈之一開 =狀態、一短路狀態與一跳火狀態（arcing status)其中之ς _2之次一主要目的在於提供一種用於一榮光燈之電 --測糸統之控制方法’其中該電流監測系 電路與-判斷電路，該方法包含下列之步驟:⑷將該= 9 1358970 燈之一燈組電流做一全波整流以產生一經整流之正弦波週 期信號；（b)藉由該偵測電路將該經整流之正弦波週期信號 轉變為一方波週期信號；（c)藉由該判斷電路以判斷該方波 週期信號是否發生變化；以及(d)當該方波週期信號發生變 化時，由該判斷電路產生一控制信號以關斷該螢光燈。 根據上述之構想，該步驟（c)更包括下列之步驟：（cl) 該判斷電路將該方波週期信號轉變為一鋸齒波週期信號； 以及（c 2)當該鋸齒波週期信號之一信號值大於一判斷準位 • 時，則該方波週期信號發生變化。 為了讓本發明之上述目的、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】 請參看第一圖，其係顯示一依據本發明構想之用於一 螢光燈的電流監測系統之方塊圖。此一依據本發明構想之 • 用於一螢光燈的電流監測系統1包含：一整流器11，其接收 該螢光燈之一燈管電流，用以產生一經整流之正弦波週期 信號，其中OC為位於該整流器11之一輸出端的一過電流節 點（over-current node)，一彳貞測電路12，其接收該經整流之 正弦波週期信號，用以產生一方波週期信號，以及一判斷 電路13，其接收該方波週期信號，並於該方波週期信號產 生變化時，由該判斷電路產生一控制信號，將該控制信號 輸入該螢光燈之一驅動電路，藉以關斷該螢光燈。 1358970 在第二圖中所示，係為一螢光燈系統，其包含一依據 本發明構想之第一較佳實施例中的整流器11之電路示意 圖。該螢光燈系統包括一變壓器TR、一第一安定器電容 Cbl、一第二安定器電容Cb2、一燈組(lamp set)與該整流器 11。其中該整流器11係為一全波整流器，其包括四個二極 體D1-D4，其輸出端連接到該OC節點。該第一安定器電容 Cbl與該變壓器連接於一節點B。 參閱第三圖，其係顯示一依據本發明構想之第一較佳 • 實施例中的偵測電路12之電路示意圖。該偵測電路12包含 一比較器，該比較器具一反相端、一非反相端與一輸出端 (其電連接一節點A)，一第一電阻R1，具一第一端與一第二 端，其中該第一端耦合於一參考電壓Vref，且該第二端耦 合於該比較器之該輸出端之該節點A，一第二電阻R2，具 一第一端與一第二端，其中該第一端耦合於該比較器之該 輸出端，且該第二端耦合於該比較器非反相端，一第三電 阻R3，具一第一端與一第二端，其中該第一端耦合於該第 • 二電阻R2之該第二端，且該第二端接地，一第四電阻R4， 具一第一端與一第二端，其中該第一端耦合於該第三電阻 R3之該第一端，且該第二端耦合於該參考電壓Vref，以及 一第五電阻R5，具一第一端與一第二端，其中該第一端耦 合於該反相端，且該第二端耦合於該整流器11之該輸出端 (該OC節點）。此處，該偵測電路12之一預定之高準位(B準 位）與一預定之低準位(A準位），可由其與該比較器電連接 之分壓電路所產生’且熟知本領域者皆知，其中. 1358970 A準位=Vref x (R2 II R3)/(R4+(R2 丨I R3))...(i);且 B準位==Vref x R3/(R3+(R4 丨丨（R1+R2)))…（2)。 第四圖（a)表示的是一依據本發明構想之第一較佳實施 例中的判斷電路13之電路示意圖。該判斷電路13包括一 正半週判斷裝置131，在該燈管電流之一正半週時接收該 。方波週期信號’用以在該正半週時產生該㈣波週期信Λ 號，一負半週判斷裝置132,在該燈管電流之一負半週時 接收該方波信號，用以在該負半週時產生_齒波週 期信號，-或閘133’具一第一端、一第二端與一輸出端， 其中該第-端接收在該正半週時所產生之_齒波週期信 號，且該第二端接收在該負半週時所產生之該鑛齒波週期 信號，以及-比較g 134,具—反相端、—非反相端與: 輪出端’其中該反相端接收該判斷準位(Vfef)，該非反相端 輕合於該或閘133之該輪出端，且該比較器134之該輸出 端用以在該異常狀態時產线㈣㈣，並透過—榮光燈 驅動電路以關斷該螢光燈。 且 上述之該正半週判斷裝置131包含：一充電器（其包含 一電流源nn，接收該參考電壓％〇，帛以產生一 流’ 一電容C1’具一第一端與一第二端’其中該第一端接 收該充電電流，用以產生該鑛齒波週期信號，且輕合於該 或閘133之該第一端’而該第二端接地，一開關，具一第 -端、-第二端與一控制端，其中該第一端輕合於該電容 之該第-端’該第二輪合於該電容之該第二端，且該控 制端接收該方波週期信號。 12 1358970 上述之該負半週判斷裝置132包含：一反相器1322， 具一第一端與一第二端，其中該第一端接收該方波週期信 號，一充電器（其包含一電流源1321，接收該參考電壓 Vrei)，用以產生一充電電流，一電容C2，具一第一端與一 第厂端，其中該第-端接收該充電電流，用以產生該鑛齒 波週期信號’且輕合於該或閘133之該第二端，而該第二 端接地’ -開關，具一第一端、一第二端與一控制端，盆 2第-端耗合於該電容C2之該第—端，該第二端輕合於 糾之該第二端，且該控制端搞合於該反相器⑽ f四圖（b)表示的是—依據本發明構想之第二較佳實 二依路13之電路示意圖。其與第四圖⑷所顯示 之^路-立'明構想之第—較佳實施例中的判斷電路13 源在於第四圖⑷中原有之該第一電流 則夂所取代’其餘部分以及其運作原理 相同:而斷電路丨3的電路示意圖 鑛齒波之上T域咖 ^ 13 i<j. 〜又較第一較佳實施例中之判斷電 路13 “緩和（在第二較佳實施 之：：電 之上升邊略呈圓弧狀，知甲之狀電路，其波形 電容之串聯電路.n 一父佳實施例中之電流源與 升形）。聯電路.1311與C1或助與C2，則呈直線上 13 1358970 在第五圖中，其係顯示一依據本發明構想之第一較佳 實施例，在正常運作時，其OC節點處之經整流的正弦波、 A節點處之方波與判斷電路所產生之判斷信號未超過判斷 準位等等的波形圖，因為是正常運作，在OC節點處之經 整流之正弦波形，其電流並無任何之異常變化，故其判斷 信號（亦即所產生之鋸齒波）並未超過一預定之判斷準位， 而其高準位(B準位）與低準位(A準位），係依據上述之公式 (1)與(2)計算而得者。 • 請參看第六圖，其係顯示一依據本發明構想之第一較 佳實施例在B節點開路時，其OC節點處之經整流的正弦 波、A節點處之方波與判斷電路所產生之判斷信號已超過 判斷準位等的波形圖。由圖中所示，因為B節點呈現開路 之狀態，以致OC節點之經整流的正弦波之波形已發生異 常之變化，有兩個負半週期之正弦波形消失了，故其相對 應之第二與第三方波波形亦產生變化，而較原有之幅度為 寬，其所產生之判斷信號的鋸齒波已超過了判斷準位（如第 • 六圖中之圈示處），如第四圖（a)所示之該比較器134的該輸 出端即產生該控制信號，並透過該螢光燈驅動電路以關斷 該螢光燈。 在第七圖中，其係顯示一依據本發明構想之第一較佳 實施例在B節點短路時，其OC節點處之經整流的正弦波、 A節點處之方波與判斷電路所產生之判斷信號已超過判斷 準位等的波形圖。由圖中所示，因為B節點呈現短路之狀 態，以致OC節點處之經整流的正弦波之波形已發生異常 14 1358970 之交化#兩個負半週期之正弦波形的幅度明顯地降低 了故其相對應之第二與第三方波波形亦產生變化，而較 原有之幅度為寬，其所產生之判斷信號的鑛齒波已超過了 判斷準位（如第七圖中之圈示處），如第四_所示之該比 較裔134的該輸出端即產生該控制信號 驅動電路以關斷該螢光燈。 蛍尤且 >閲第八圖’其係顯示—依據本發明構想之第一較佳 實施例在B節點跳火時其〇c節點處之經整流的正弦波、A 即點處之方波與騎電路難生之_錢已超過判斷準 位等的波形圖。由圖中所示，因為B節點呈現跳火之狀態， 以致OC節點處之經整流的正弦波之波形已發生異常之變 化，，有兩個負半週期之正弦波形各自與相對應之前一個正 半週期之正弦波形重疊，故其相對應之第二與第三 形消失’其所產生之相對應之判斷錢的㈣波㈣過/了 判斷準位（如第八圖中之圈示處），如第四圖⑷所示之該比 較器m的該輸出端即產生該控制信號，並透過該螢光燈 驅動電路以關斷該螢光燈。 由上述的說明可知，本發明在於提供-種用於-螢光 燈之電流監測系統’將該f光燈之—燈組電流做一整流， 藉由-偵測電路將該經整流之f流信號轉變為—方好 號，，藉由-判斷電路以判斷該方波信號是否發生變化，以 及當该方波彳§號發錢化時，由該輯電路產生—控制信 號以關斷該螢光燈。該電流監測系統可運用於監測^榮^ 燈發生開路、短路及跳火等不同之異常狀態，且其電路之 1358970 結構相對較簡單，故其具有一相對較佳之效益與一相對較 低之總成本等優點。 是以，縱使本案已由上述之實施例所詳細敘述而可由 熟悉本技藝之人士任施匠思而為諸般修飾，然皆不脫如附 申請專利範圍所欲保護者。 【圖式簡單說明】 第一圖：其係顯示一依據本發明構想之用於一螢光燈的電 • 流監測系統之方塊圖； 第二圖：其係顯示一螢光燈系統包含一依據本發明構想之 第一較佳實施例中的整流器之電路示意圖； 第三圖：其係顯示一依據本發明構想之第一較佳實施例中 的偵測電路之電路示意圖； 第四圖（a):其係顯示一依據本發明構想之第一較佳實施例 中的判斷電路之電路示意圖； 第四圖（b):其係顯示一依據本發明構想之第二較佳實施例 • 中的判斷電路之電路示意圖； 第五圖：其係顯示一依據本發明構想之第一較佳實施例在 正常運作時其OC節點處之經整流的正弦波、A節點處之 方波與判斷電路所產生之判斷信號未超過判斷準位等的波 形圖， 第六圖：其係顯示一依據本發明構想之第一較佳實施例在 B節點開路時其OC節點處之經整流的正弦波、A節點處之 方波與判斷電路所產生之判斷信號已超過判斷準位等的波 16 1358970 « 形圖； 第七圖：其係顯示-依據本發明構想之第 短路時其0C節點處之經整流的正弦波、A節點:之 形圖ΓΓ路職生之騎信號已超過⑽準位等的波 第八圖.其係顯示—依據本發明構想之第-較佳實施例在 B節點跳火時其OC節點處之經整流的正弦波、a節點處之^π-ring, the first end of the dan 琢 is coupled to the second end of the second resistor, and the second end is grounded, and a fourth resistor has a first end and a second end, wherein the first The first end is coupled to the first end of the third resistor, and the second end is coupled to the reference voltage, and the fifth resistor has a first end and a second end, wherein the first end is coupled to the comparison The inverting terminal is coupled to the output of the rectifier. According to the above concept, the judging circuit comprises a positive half-cycle judging device receiving the square wave period signal during the positive half cycle of the headlight current for generating the line_wave period signal during the positive half cycle, The half-cycle_device, purely the square wave (four) signal at the half-cycle of the lamp current, used to generate the periodic signal of the ore wave during the negative half cycle, H, end, - end - and An output end, wherein the first end receives the sawtooth periodic signal generated during the positive period, and the second end receives the mineral tooth wave periodic signal generated during the “week”, and the −inverting end a non-inverting end and a round out 嫂. — 龄 Α , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , 8 1358970 The terminal is used to generate the control signal in the abnormal state. According to the above concept, the positive half-cycle judging device includes a charger having a current source and a resistor, and receiving a reference. a voltage for generating a charging current, a capacitor having a first end and a second end, :, The Haidi cake receives the charging current for generating the sawtooth period and is coupled to the first end of the gate, and the second end is grounded, and the first end is connected to the second end. a control terminal, wherein the first end face is at the first end of the electric valley, the second end is coupled to the second end of the capacitor, and the control end receives the square wave periodic signal. The negative half-cycle judging device includes an inverter having a first end and a second end, wherein the first end receives the square wave periodic signal 'a charger, having both a current source and a current And receiving a reference electric dust for generating a charging current, a capacitor, and a first end and a second end, wherein the first end receives the charging current, to generate the sawtooth periodic signal, And coupled to the second end of the gate, and the second end is grounded to a switch having a first end, a second end and a control end, and the first wheel is coupled to the first end of the capacitor The second end is coupled to the second end of h-present, and the control end is coupled to the second end of the inverter. In the above concept, the abnormal state is selected from one of the fluorescent lamp's open state, a short circuit state, and an arcing state, the second of which is to provide a glory light. The control method of the electric system--the current monitoring system circuit and the judging circuit, the method comprises the following steps: (4) performing a full-wave rectification of one of the lamps of the = 9 1358970 lamp to generate a rectified a sinusoidal periodic signal; (b) converting the rectified sinusoidal periodic signal into a square wave periodic signal by the detecting circuit; (c) determining, by the determining circuit, whether the square wave periodic signal changes; (d) When the square wave periodic signal changes, a control signal is generated by the determining circuit to turn off the fluorescent lamp. According to the above concept, the step (c) further includes the following steps: (cl) the determining The circuit converts the square wave periodic signal into a sawtooth periodic signal; and (c 2) when the signal value of one of the sawtooth periodic signals is greater than a judgment level, the square wave periodic signal changes. The above described objects, features and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the invention. A block diagram of a current monitoring system for a fluorescent lamp in accordance with the teachings of the present invention is shown. The current monitoring system 1 for a fluorescent lamp according to the present invention comprises: a rectifier 11 that receives a lamp current of the fluorescent lamp for generating a rectified sinusoidal periodic signal, wherein OC An over-current node located at an output end of the rectifier 11, a sensing circuit 12 receiving the rectified sine wave periodic signal for generating a square wave periodic signal and a determining circuit 13. Receiving the square wave periodic signal, and when the square wave periodic signal changes, the determining circuit generates a control signal, and the control signal is input to a driving circuit of the fluorescent lamp, thereby turning off the fluorescent light. light. 1358970 is shown in the second figure as a fluorescent lamp system comprising a schematic circuit diagram of a rectifier 11 in accordance with a first preferred embodiment of the present invention. The fluorescent lamp system includes a transformer TR, a first ballast capacitor Cbl, a second ballast capacitor Cb2, a lamp set, and the rectifier 11. The rectifier 11 is a full-wave rectifier comprising four diodes D1-D4, the output of which is connected to the OC node. The first ballast capacitor Cbl is coupled to the transformer to a node B. Referring to the third figure, there is shown a circuit diagram of a detection circuit 12 in a first preferred embodiment in accordance with the teachings of the present invention. The detecting circuit 12 includes a comparator, an inverting terminal, a non-inverting terminal and an output terminal (which are electrically connected to a node A), and a first resistor R1 having a first end and a first a second end, wherein the first end is coupled to a reference voltage Vref, and the second end is coupled to the node A of the output end of the comparator, a second resistor R2 having a first end and a second end The first end is coupled to the output end of the comparator, and the second end is coupled to the non-inverting terminal of the comparator, and a third resistor R3 has a first end and a second end, wherein the first end The first end is coupled to the second end of the second resistor R2, and the second end is grounded, and the fourth resistor R4 has a first end and a second end, wherein the first end is coupled to the first end The first end of the three resistors R3, the second end is coupled to the reference voltage Vref, and a fifth resistor R5 having a first end and a second end, wherein the first end is coupled to the inverting end And the second end is coupled to the output of the rectifier 11 (the OC node). Here, a predetermined high level (B level) of the detecting circuit 12 and a predetermined low level (A level) can be generated by a voltage dividing circuit electrically connected to the comparator. It is well known in the art, wherein 1358970 A level = Vref x (R2 II R3) / (R4 + (R2 丨 I R3)) (i); and B level == Vref x R3 / (R3+ (R4 丨丨(R1+R2)))...(2). The fourth diagram (a) shows a circuit diagram of the judging circuit 13 in the first preferred embodiment in accordance with the teachings of the present invention. The judging circuit 13 includes a positive half cycle judging means 131 which receives the positive half cycle of the lamp current. The square wave periodic signal 'is used to generate the (four) wave period signal 在 at the positive half cycle, and the negative half cycle determining means 132 receives the square wave signal at one negative half cycle of the lamp current for The negative half cycle generates a _ tooth wave periodic signal, and the gate 133 ′ has a first end, a second end and an output end, wherein the first end receives the _ tooth wave generated during the positive half cycle a periodic signal, and the second end receives the orthodontic period signal generated during the negative half cycle, and - compares g 134, has an inverting end, a non-inverting end, and a: a round end The inverting terminal receives the determining level (Vfef), the non-inverting terminal is lightly coupled to the rounding end of the OR gate 133, and the output end of the comparator 134 is used to produce a line (4) (4) in the abnormal state, and Pass the glory drive circuit to turn off the fluorescent light. And the positive half-cycle judging device 131 includes: a charger (including a current source nn, receiving the reference voltage % 〇, to generate a first-class 'one capacitor C1' having a first end and a second end' The first end receives the charging current for generating the mineral tooth wave periodic signal, and is lightly coupled to the first end of the OR gate 133 and the second end is grounded, and a switch has a first end, a second end and a control end, wherein the first end is lightly coupled to the first end of the capacitor. The second end is coupled to the second end of the capacitor, and the control end receives the square wave periodic signal. 12 1358970 The negative half-cycle determining device 132 includes: an inverter 1322 having a first end and a second end, wherein the first end receives the square wave periodic signal, and a charger (which includes a current) The source 1321 receives the reference voltage Vrei) for generating a charging current, and the capacitor C2 has a first end and a first factory end, wherein the first end receives the charging current for generating the ore wave period The signal 'and is lightly coupled to the second end of the OR gate 133, and the second end is grounded' - The switch has a first end, a second end and a control end, the first end of the basin 2 is coupled to the first end of the capacitor C2, and the second end is lightly coupled to the second end, and the second end The control terminal is engaged with the inverter (10). FIG. 4(b) shows a circuit diagram of the second preferred real two-way circuit 13 according to the present invention, which is shown in the fourth figure (4). The judgment circuit 13 in the preferred embodiment is based on the fact that the first current in the fourth diagram (4) is replaced by the 'other part' and the operation principle is the same: the circuit of the circuit 丨3 is broken. The T-domain coffee on the schematic orthodontic wave is further relaxed than the determination circuit 13 in the first preferred embodiment (in the second preferred embodiment: the rising edge of the electric is slightly arcuate) , the circuit of the Zhijia, its series circuit of waveform capacitors. n The current source and the ascending shape in a parent's embodiment. The circuit. 1311 and C1 or the help of C2, in a straight line 13 1358970 In the fifth picture , which shows a rectified sine wave at its OC node during normal operation, in accordance with a first preferred embodiment of the present invention. The square wave at the A node and the judgment signal generated by the judgment circuit do not exceed the waveform of the judgment level, etc., because it is normal operation, the rectified sinusoidal waveform at the OC node does not have any abnormal change in current. Therefore, the judgment signal (that is, the generated sawtooth wave) does not exceed a predetermined judgment level, and the high level (B level) and the low level (A level) are based on the above formula (1). And (2) calculated. • Please refer to the sixth figure, which shows a rectified sine wave at the OC node when the Node B is opened in accordance with the first preferred embodiment of the present invention. The square wave of the node and the judgment signal generated by the judgment circuit have exceeded the waveform of the judgment level, etc. As shown in the figure, since the B node exhibits an open state, the waveform of the rectified sine wave of the OC node has occurred. The abnormality changes, the sinusoidal waveform with two negative half cycles disappears, so the corresponding second and third-party waveforms also change, and the amplitude is wider than the original one, and the sawtooth wave of the judgment signal generated is Has exceeded the judgment level (such as the first • The circle shown in the sixth figure), the output terminal of the comparator 134 shown in the fourth figure (a) generates the control signal and passes through the fluorescent lamp driving circuit to turn off the fluorescent lamp. In the seventh figure, a rectified sine wave at the OC node, a square wave at the A node, and a judging circuit are generated when the B node is short-circuited according to the first preferred embodiment of the present invention. The waveform of the judgment signal has exceeded the judgment level. As shown in the figure, because the B-node exhibits a short-circuit state, the waveform of the rectified sine wave at the OC node has an abnormality. 14 1358970 Intersection # The amplitude of the two negative half-cycle sinusoidal waveforms is significantly reduced. The corresponding second and third-party wave waveforms also change, and the amplitude is wider than the original one. The detected tooth wave of the judgment signal has exceeded the judgment level (as shown in the seventh figure). The output terminal of the comparator 134, as shown in the fourth embodiment, generates the control signal driving circuit to turn off the fluorescent lamp.尤尤和> Read the eighth figure's display - a rectified sine wave at the 〇c node and a square wave at the point A in the B-node flashover according to the first preferred embodiment of the present invention It is difficult to ride the circuit. The money has exceeded the waveform of the judgment level. As shown in the figure, since the B node exhibits a state of flashover, so that the waveform of the rectified sine wave at the OC node has abnormally changed, there are two negative half cycles of the sinusoidal waveforms respectively corresponding to the previous one. The sinusoidal waveforms of the half cycle overlap, so the corresponding second and third shapes disappear. 'The corresponding (4) wave (four) of the judgment money (the fourth) is over/the judgment level (as shown in the eighth figure) The output of the comparator m as shown in the fourth figure (4) generates the control signal and passes through the fluorescent lamp driving circuit to turn off the fluorescent lamp. It can be seen from the above description that the present invention provides a current monitoring system for a fluorescent lamp to rectify the lamp current of the f-light, and the rectified f-flow is performed by a detecting circuit. The signal is converted to a square good, and the determining circuit determines whether the square wave signal changes, and when the square wave 彳§ is issued, the control circuit generates a control signal to turn off the firefly. Lights. The current monitoring system can be used to monitor different abnormal states such as open circuit, short circuit and flashover of the ^^^ lamp, and the structure of the circuit 1358970 is relatively simple, so it has a relatively good benefit and a relatively low total. Cost and other advantages. Therefore, even if the present invention has been described in detail by the above-described embodiments, it can be modified by those skilled in the art, and is not intended to be protected by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an electric current monitoring system for a fluorescent lamp according to the present invention; FIG. 2 is a diagram showing a fluorescent lamp system including a basis. A circuit diagram of a rectifier in a first preferred embodiment of the present invention; FIG. 3 is a circuit diagram showing a detection circuit in accordance with a first preferred embodiment of the present invention; The following is a circuit diagram showing a judging circuit in a first preferred embodiment of the present invention; and FIG. 4(b) is a second preferred embodiment in accordance with the teachings of the present invention. Circuit diagram of the judgment circuit; FIG. 5 is a diagram showing a rectified sine wave at the OC node, a square wave at the A node, and a judgment circuit in a normal operation according to the first preferred embodiment of the present invention. The generated determination signal does not exceed the waveform of the judgment level, etc., and the sixth figure shows a rectified sine wave at the OC node when the Node B is opened according to the first preferred embodiment of the present invention. At the node The wave and the judgment signal generated by the judgment circuit have exceeded the wave of the judgment level, etc. 16 1358970 «Chart; seventh diagram: the display shows - the rectified sine wave at the 0C node when the short circuit is according to the present invention, A node: the figure of the road has a riding signal that exceeds the (10) level and the like. The figure shows that the OC node at the B node jumps fire according to the first preferred embodiment of the present invention. Rectified sine wave, at node a
方波與判斷電路所產生之騎信號已超過麟準位等的波 形圖。 【主要元件符號說明】 :依據本發明構想之螢光燈的電流監測系統 Π :整流器 13 :判斷電路 1311 :第一電流源 1321 :第二電流源 133 :或閘 12 :偵測電路 131 :正半週判斷裝置 132 :負半週判斷装置 1322 :反相器 134 :比較器 17The riding signal generated by the square wave and the judging circuit has exceeded the waveform diagram of the lining level. [Main component symbol description]: Current monitoring system of fluorescent lamp according to the present invention: Rectifier 13: Judging circuit 1311: First current source 1321: Second current source 133: or Gate 12: Detection circuit 131: Positive Half-cycle judging device 132: negative half-cycle judging device 1322: inverter 134: comparator 17