JPH1116694A - Discharge lamp lighting device - Google Patents
Discharge lamp lighting deviceInfo
- Publication number
- JPH1116694A JPH1116694A JP16992997A JP16992997A JPH1116694A JP H1116694 A JPH1116694 A JP H1116694A JP 16992997 A JP16992997 A JP 16992997A JP 16992997 A JP16992997 A JP 16992997A JP H1116694 A JPH1116694 A JP H1116694A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- frequency
- ceramic transformer
- lighting device
- oscillator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Circuit Arrangements For Discharge Lamps (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は放電灯点灯装置に関
する。The present invention relates to a discharge lamp lighting device.
【０００２】[0002]
【従来の技術】従来の放電灯点灯装置は実開平6−16769
4 号公報に記載されているように、セラミックトランス
の駆動電圧を制御することによって冷陰極放電管を点灯
させる。つまり、セラミックトランスの昇圧比の周波数
特性を利用して得た高電圧によって冷陰極放電管を点灯
させるセラミックトランスを用いた冷陰極放電管点灯装
置において、発振器からの出力をセラミックトランスに
与え、前記出力の周波数を高い方から低い方に掃引し
て、周波数の減少に伴いセラミックトランスの昇圧比が
増加するといった昇圧比の周波数特性の急傾斜によって
冷陰極放電管を点灯させる。2. Description of the Related Art A conventional discharge lamp lighting device is disclosed in Japanese Utility Model Laid-Open No. 6-16769.
As described in Japanese Patent Publication No. 4 (1993), a cold cathode discharge tube is turned on by controlling a driving voltage of a ceramic transformer. That is, in a cold-cathode discharge tube lighting device using a ceramic transformer for lighting a cold-cathode discharge tube with a high voltage obtained by utilizing a frequency characteristic of a boost ratio of a ceramic transformer, an output from an oscillator is given to the ceramic transformer. The output frequency is swept from high to low, and the cold cathode discharge tube is turned on by the steep slope of the frequency characteristic of the boost ratio such that the boost ratio of the ceramic transformer increases as the frequency decreases.
【０００３】[0003]
【発明が解決しようとする課題】上記の方式では始動時
の動作を停止させる手段がない。すなわち、例えばセラ
ミックトランスを無負荷で動作させた場合、セラミック
トランスの共振点付近の周波数で動作させると、出力電
圧が上がり過ぎ、極端な場合には絶縁破壊を起こす可能
性がある。そのためセラミックトランスの２次側が、絶
縁破壊の発生しない電圧以下に抑えて使用する必要があ
る。このため周波数を高い方から低い方へ掃引させ、セ
ラミックトランスの出力電圧が所定の値以上になったと
きは、周波数を高い方へ戻してから再び低い方へ掃引す
る方法が考えられる。しかしこの場合、出力には高圧が
発生し続けるため、使用者が誤って出力部分に手を触
れ、感電する危険性があった。In the above method, there is no means for stopping the operation at the time of starting. That is, for example, when the ceramic transformer is operated with no load, when the ceramic transformer is operated at a frequency near the resonance point, the output voltage becomes excessively high, and in extreme cases, there is a possibility of causing dielectric breakdown. Therefore, the secondary side of the ceramic transformer must be used at a voltage lower than the voltage at which no dielectric breakdown occurs. For this reason, a method is considered in which the frequency is swept from the higher side to the lower side, and when the output voltage of the ceramic transformer exceeds a predetermined value, the frequency is returned to the higher side and then swept down again. However, in this case, since a high voltage continues to be generated in the output, there is a risk that the user may accidentally touch the output portion and receive an electric shock.
【０００４】[0004]
【課題を解決するための手段】上記の危険を防止するた
め、放電灯点灯装置において、トランス前段に設けた発
振器の出力をセラミックトランスに与え、前記出力の周
波数を高い方から低い方に掃引して、セラミックトラン
スの駆動周波数を制御することによって冷陰極放電管を
点灯させる際に、セラミックトランスの２次電圧が所定
値以上になったことを検出する手段とこれら検出手段の
出力により周波数を高い方にリセットして再点灯する手
段を具備し、前記の放電管の始動動作が予め定めた所定
時間以上行われたときに動作を停止する機能を設けるこ
とで長時間高圧を出力することを防止することができ
る。In order to prevent the above danger, in a discharge lamp lighting device, the output of an oscillator provided in the front stage of a transformer is supplied to a ceramic transformer, and the frequency of the output is swept from a higher frequency to a lower frequency. When the cold cathode discharge tube is turned on by controlling the driving frequency of the ceramic transformer, the frequency is increased by means for detecting that the secondary voltage of the ceramic transformer has exceeded a predetermined value and the output of these detecting means. To prevent the output of high voltage for a long time by providing a means for resetting and re-lighting, and a function of stopping the operation when the starting operation of the discharge tube is performed for a predetermined time or more. can do.
【０００５】[0005]
【発明の実施の形態】本発明の実施例を図１に示す放電
灯点灯装置の回路図を用いて説明する。図中、１は直流
電源、２は発振器、３はセラミックトランス、４は冷陰
極管、５は管電流検出器、６は誤差増幅器、７は基準電
圧源、８はＶ／Ｆコンバータ、９及び１０は抵抗、１１
は整流平滑用ダイオード、１２は誤差増幅器、１３は基
準電圧源、１４はリセット回路、１５はコンデンサ、１
６は判定回路、１７はコンデンサ、１８は遮断回路であ
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to a circuit diagram of a discharge lamp lighting device shown in FIG. In the figure, 1 is a DC power supply, 2 is an oscillator, 3 is a ceramic transformer, 4 is a cold cathode tube, 5 is a tube current detector, 6 is an error amplifier, 7 is a reference voltage source, 8 is a V / F converter, 9 and 10 is a resistor, 11
Is a rectifying / smoothing diode, 12 is an error amplifier, 13 is a reference voltage source, 14 is a reset circuit, 15 is a capacitor,
6 is a judgment circuit, 17 is a capacitor, and 18 is a cutoff circuit.
【０００６】図２はセラミックトランスの出力電圧の周
波数特性の例を負荷抵抗が大きい場合（冷陰極管の点灯
前の状態）を実線で、小さい場合（冷陰極管の点灯後）
を破線で示したものである。FIG. 2 shows an example of the frequency characteristics of the output voltage of the ceramic transformer when the load resistance is large (the state before the CCFL is turned on) and when it is small (after the CCFL is turned on).
Are indicated by broken lines.
【０００７】直流電源１の直流電圧は、発振器２によっ
て交流電圧に変換され、セラミックトランス３に入力さ
れる。このとき発振器２の出力はＶ／Ｆコンバータ８に
よって決められた周波数によって動作する。冷陰極ラン
プ４の点灯前は、図２の周波数ｆａにて駆動し始め、低
い周波数へと掃引される。周波数が下がってきて、セラ
ミックトランスの出力電圧が冷陰極ランプ４の放電開始
電圧Ｖｂよりも高くなると冷陰極ランプ４は点灯する。
冷陰極ランプ４が点灯を開始すると冷陰極ランプ４を流
れる電流は管電流検出器５によって電圧に変換され、誤
差増幅器６によって基準電圧源７の基準電圧と比較され
る。この結果Ｖ／Ｆコンバータ８は、冷陰極ランプ４に
点灯維持電圧Ｖｄが印加されるよう発振器２を周波数ｆ
ｄにて駆動するよう制御する。[0007] The DC voltage of the DC power supply 1 is converted into an AC voltage by the oscillator 2 and input to the ceramic transformer 3. At this time, the output of the oscillator 2 operates at the frequency determined by the V / F converter 8. Before the cold cathode lamp 4 is turned on, driving is started at the frequency fa in FIG. 2 and the frequency is swept to a lower frequency. When the frequency decreases and the output voltage of the ceramic transformer becomes higher than the discharge starting voltage Vb of the cold cathode lamp 4, the cold cathode lamp 4 is turned on.
When the cold cathode lamp 4 starts lighting, the current flowing through the cold cathode lamp 4 is converted into a voltage by the tube current detector 5 and compared with the reference voltage of the reference voltage source 7 by the error amplifier 6. As a result, the V / F converter 8 changes the frequency of the oscillator 2 so that the lighting sustain voltage Vd is applied to the cold cathode lamp 4.
Control to drive by d.
【０００８】以上が冷陰極ランプ４が点灯を行うまでの
放電灯点灯装置の基本的な動作である。ここでＶ／Ｆコ
ンバータ８の動作周波数とコンデンサ１５の両端電圧の
関係を図３に示す。前記周波数の掃引はコンデンサ１５
の電荷を重放電することで両端電圧を変化させて行う。The above is the basic operation of the discharge lamp lighting device until the cold cathode lamp 4 is turned on. FIG. 3 shows the relationship between the operating frequency of the V / F converter 8 and the voltage across the capacitor 15. The frequency is swept by the capacitor 15
This is performed by changing the voltage between both ends by performing heavy discharge of the electric charges of the above.
【０００９】次に放電灯点灯装置が無負荷にて駆動した
場合の動作を説明する。無負荷時には管電流検出器５が
ゼロ電圧を出力するので、Ｖ／Ｆコンバータ８はコンデ
ンサ１５が充電され続けるため発振器２の駆動周波数を
ｆｂよりさらに低い周波数へ掃引する。このため発振器
２の駆動周波数がセラミックトランス３の共振周波数に
近づくにしたがって、セラミックトランス３の２次電圧
は急激に上昇する。Next, the operation when the discharge lamp lighting device is driven with no load will be described. When no load is applied, the tube current detector 5 outputs a zero voltage, so that the V / F converter 8 sweeps the drive frequency of the oscillator 2 to a frequency lower than fb because the capacitor 15 continues to be charged. Therefore, as the driving frequency of the oscillator 2 approaches the resonance frequency of the ceramic transformer 3, the secondary voltage of the ceramic transformer 3 sharply increases.
【００１０】この２次電圧は抵抗９と１０によって分圧
され、ダイオード１１によって整流され誤差増幅器１２
に入力される。この入力された電圧は、基準電圧源１３
の基準電圧と比較される。これによりセラミックトラン
ス３の２次側電圧がセラミックトランスが絶縁破壊を起
こさない所定の電圧Ｖｃを超えたとき、誤差増幅器１２
の出力値が反転するように抵抗９及び１０を設定する。
誤差増幅器１２の出力値が反転することによりリセット
回路１４が働き、コンデンサ１５に充電されている電荷
を放電する。このためＶ／Ｆコンバータ８は再度、周波
数ｆａから掃引を開始する。This secondary voltage is divided by the resistors 9 and 10, rectified by the diode 11, and
Is input to This input voltage is supplied to the reference voltage source 13
Is compared with the reference voltage. Accordingly, when the secondary voltage of the ceramic transformer 3 exceeds a predetermined voltage Vc at which the ceramic transformer does not cause dielectric breakdown, the error amplifier 12
The resistors 9 and 10 are set so that the output value is inverted.
When the output value of the error amplifier 12 is inverted, the reset circuit 14 operates to discharge the electric charge stored in the capacitor 15. Therefore, the V / F converter 8 starts sweeping again from the frequency fa.
【００１１】次に判定回路１６について説明する。判定
回路１６はコンデンサ１５の両端電圧が所定レベル以下
の時、コンデンサ１７を所定の電流で充電する。したが
って冷陰極ランプ４が未接続の場合、コンデンサ１５の
両端電圧はリセット回路１４の動作により所定の電圧値
に達せず、そのため判定回路１６はコンデンサ１７を所
定の電流で充電する。コンデンサ１７の両端電圧が所定
の値まで充電されると遮断回路１８が動作し、Ｖ／Ｆコ
ンバータ８を停止させ、放電灯点灯装置は動作を停止す
る。このときのＶ／Ｆコンバータ８の周波数と２次電圧
とコンデンサ１５の両端電圧とコンデンサ１７の両端電
圧の関係を図４に示す。Next, the determination circuit 16 will be described. The judgment circuit 16 charges the capacitor 17 with a predetermined current when the voltage between both ends of the capacitor 15 is lower than a predetermined level. Therefore, when the cold cathode lamp 4 is not connected, the voltage between both ends of the capacitor 15 does not reach the predetermined voltage value due to the operation of the reset circuit 14, so that the determination circuit 16 charges the capacitor 17 with the predetermined current. When the voltage between both ends of the capacitor 17 is charged to a predetermined value, the cutoff circuit 18 operates, stops the V / F converter 8, and stops the operation of the discharge lamp lighting device. FIG. 4 shows the relationship between the frequency of the V / F converter 8, the secondary voltage, the voltage across the capacitor 15, and the voltage across the capacitor 17 at this time.
【００１２】[0012]
【発明の効果】以上に説明したように、本発明によれば
セラミックトランスを用いた放電灯点灯装置の異常時で
の動作の安全性を確保できる。つまり、セラミックトラ
ンスが不適切な周波数で長時間駆動することがなくな
り、セラミックトランスが絶縁破壊を起こすような異常
動作を停止することができる。且つ、長時間高圧を出力
することを防止するため、従来にない安全性を高めた放
電灯点灯装置を実現できる。As described above, according to the present invention, the safety of operation of the discharge lamp lighting device using the ceramic transformer at the time of abnormality can be ensured. That is, the ceramic transformer is not driven at an inappropriate frequency for a long time, and an abnormal operation that causes dielectric breakdown of the ceramic transformer can be stopped. In addition, it is possible to realize a discharge lamp lighting device with unprecedented safety enhanced in order to prevent output of a high voltage for a long time.
【図１】本発明の第一の実施例の回路図。FIG. 1 is a circuit diagram of a first embodiment of the present invention.
【図２】本発明のセラミックトランスの昇圧比と周波数
特性を示す動作説明図。FIG. 2 is an operation explanatory diagram showing a boost ratio and frequency characteristics of the ceramic transformer of the present invention.
【図３】第一の実施例の動作説明図。FIG. 3 is an operation explanatory diagram of the first embodiment.
【図４】第一の実施例の動作説明図。FIG. 4 is an operation explanatory diagram of the first embodiment.
１…直流電源、２…発振器、３…セラミックトランス、
４…冷陰極ランプ、５…管電流検出器、８…Ｖ／Ｆコン
バータ、１４…リセット回路、１６…判定回路、１８…
遮断回路。1. DC power supply, 2. Oscillator, 3. Ceramic transformer,
4: cold cathode lamp, 5: tube current detector, 8: V / F converter, 14: reset circuit, 16: determination circuit, 18:
Cutoff circuit.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 池田 隆一 神奈川県横浜市戸塚区吉田町292番地 株 式会社日立画像情報システム内 (72)発明者 杉野 元洋 神奈川県横浜市戸塚区吉田町292番地 株 式会社日立画像情報システム内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ryuichi Ikeda 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi Image Information System Co., Ltd. (72) Motohiro Sugino 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Image Information System Co., Ltd.
Claims (1)
力する交流電圧の周波数を制御する手段と、上記トラン
スの出力に接続された冷陰極放電管と、上記トランスに
入力される交流電圧の周波数が所定の値以上であること
を検出する手段を具備し、前記周波数が所定の周波数以
上になる状態を一定時間以上継続した場合に動作を停止
することを特徴とした放電灯点灯装置。1. A ceramic transformer, means for controlling a frequency of an AC voltage input to the transformer, a cold cathode discharge tube connected to an output of the transformer, and a frequency of the AC voltage input to the transformer being predetermined. The discharge lamp lighting device further comprises means for detecting that the frequency is equal to or higher than a predetermined value, and stops the operation when the state in which the frequency is equal to or higher than a predetermined frequency is continued for a predetermined time or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16992997A JPH1116694A (en) | 1997-06-26 | 1997-06-26 | Discharge lamp lighting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16992997A JPH1116694A (en) | 1997-06-26 | 1997-06-26 | Discharge lamp lighting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH1116694A true JPH1116694A (en) | 1999-01-22 |
Family
ID=15895559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16992997A Pending JPH1116694A (en) | 1997-06-26 | 1997-06-26 | Discharge lamp lighting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH1116694A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011238421A (en) * | 2010-05-10 | 2011-11-24 | Taiheiyo Cement Corp | Piezoelectric transformer control circuit |
-
1997
- 1997-06-26 JP JP16992997A patent/JPH1116694A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011238421A (en) * | 2010-05-10 | 2011-11-24 | Taiheiyo Cement Corp | Piezoelectric transformer control circuit |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6504315B2 (en) | Lamp system with electronic ballast | |
| JP3061043B2 (en) | Power supply circuit | |
| EP0636284B1 (en) | Power supply | |
| JPH11503266A (en) | Electronic lamp protection ballast | |
| US6377000B2 (en) | Electronic ballast for gas discharge lamp | |
| JP2000123970A (en) | Circuit for indirectly controlling output voltage of electroluminescent lamp drive and its method | |
| JP2002083699A (en) | Electric discharge lamp lighting equipment | |
| JP3500815B2 (en) | Discharge lamp lighting device | |
| JP3492882B2 (en) | Switching power supply | |
| JP4063625B2 (en) | Discharge lamp lighting device | |
| JPH04342993A (en) | Discharge lamp lighting device | |
| JPH1116694A (en) | Discharge lamp lighting device | |
| JPS6024669B2 (en) | Intermittent transistor DC converter | |
| JPH11144860A (en) | High frequency heating apparatus | |
| US20050062425A1 (en) | Method and apparatus for a voltage controlled start-up circuit for an electronic ballast | |
| JP3242314B2 (en) | Power supply unit for discharge lamp | |
| JP2529312Y2 (en) | Discharge lamp lighting device | |
| JP3831983B2 (en) | Discharge lamp lighting device | |
| JP3106643B2 (en) | Discharge lamp lighting device and lighting equipment using this lighting device | |
| JP3511661B2 (en) | Power supply for low voltage bulb | |
| JP3395795B2 (en) | Discharge lamp lighting device | |
| JPS60240099A (en) | Devide for firing discharge lamp | |
| JP3835105B2 (en) | Discharge lamp lighting device | |
| JP3129036B2 (en) | Switching power supply | |
| JP3405024B2 (en) | Power supply |