JPH04141989A - Discharge lamp lighting device - Google Patents
Discharge lamp lighting deviceInfo
- Publication number
- JPH04141989A JPH04141989A JP2261975A JP26197590A JPH04141989A JP H04141989 A JPH04141989 A JP H04141989A JP 2261975 A JP2261975 A JP 2261975A JP 26197590 A JP26197590 A JP 26197590A JP H04141989 A JPH04141989 A JP H04141989A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- discharge lamp
- diode
- time constant
- capacitor
- 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
- 239000003990 capacitor Substances 0.000 claims abstract description 36
- 238000007599 discharging Methods 0.000 claims abstract description 6
- 230000010355 oscillation Effects 0.000 claims description 12
- 230000000694 effects Effects 0.000 claims description 7
- 238000001514 detection method Methods 0.000 abstract description 6
- 238000006243 chemical reaction Methods 0.000 description 15
- 238000009499 grossing Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 2
Landscapes
- Circuit Arrangements For Discharge Lamps (AREA)
- Inverter Devices (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は放電灯点灯装置に係り、特に点灯回路のＬＣ共
振によって始動時昇圧作用を持たせる回路で、しかもイ
ンバータ回路を用いて高周波点灯する場合に、始動時、
インバータ回路に過電流が流れないようにかつ、放電灯
にかかる電圧を一定化するようスイッチング周波数を制
御するようにした放電灯点灯装置の改良に関する。[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a discharge lamp lighting device, and in particular to a circuit that provides a voltage boosting effect at the time of starting through LC resonance of a lighting circuit, and moreover, an inverter circuit. When starting, when using high frequency lighting,
The present invention relates to an improvement in a discharge lamp lighting device in which the switching frequency is controlled so as to prevent overcurrent from flowing through an inverter circuit and to keep the voltage applied to the discharge lamp constant.
（従来の技術）
従来、この種の放電灯点灯装置は、単相交流電源から供
給される交流を全波整流等して平滑し、これをチョッパ
回路でスイッチングして昇圧した後に平滑し、この平滑
後の直流をインバータでスイッチングして所望の交流電
圧を得て、これを負荷となる放電灯に印加して放電灯を
高周波点灯するようにしたものである。このような点灯
回路において、ＬＣの共振を利用して、始動時に昇圧作
用を持たせるようにしたものがある。(Prior art) Conventionally, this type of discharge lamp lighting device smoothes the AC supplied from a single-phase AC power supply by full-wave rectification, boosts the voltage by switching it with a chopper circuit, and then smoothes the AC supplied from a single-phase AC power supply. A desired alternating current voltage is obtained by switching the smoothed direct current using an inverter, and this is applied to a discharge lamp serving as a load to light the discharge lamp at a high frequency. Among such lighting circuits, there is one that utilizes the resonance of the LC to provide a boosting effect at the time of starting.
第２図は従来の放電灯点灯装置の一例を示す。FIG. 2 shows an example of a conventional discharge lamp lighting device.
第２図において、放電灯点灯装置１は、全波整流回路２
と、昇圧チョッパ回路３と、平滑コンデンサ４と、イン
バータ回路５と、電流制限用コイル６と、このコイルと
共に共振回路を構成する共振コンデンサ７と、放電灯８
と、インバータ回路５のスイッチングを制御する電圧
周波数変換回路（Ｖ／Ｆ変換回路）９と、始動時の放電
灯端子電圧を検出して該端子電圧を低い値がらスタート
するよう電圧・周波数変換回路９の入力電圧を制御する
制御図ＮＩＯとを備え、次のように構成されている。In FIG. 2, a discharge lamp lighting device 1 includes a full-wave rectifier circuit 2.
, a boost chopper circuit 3, a smoothing capacitor 4, an inverter circuit 5, a current limiting coil 6, a resonant capacitor 7 that constitutes a resonant circuit together with this coil, and a discharge lamp 8.
and a voltage that controls the switching of the inverter circuit 5.
A frequency conversion circuit (V/F conversion circuit) 9, a control diagram NIO that detects the discharge lamp terminal voltage at the time of starting, and controls the input voltage of the voltage/frequency conversion circuit 9 so that the terminal voltage starts at a low value. It is structured as follows.
即ち、全波整流回路２は、単相交流電源１１の交流を全
波整流し、これを昇圧チョッパ回路３に供給する。この
昇圧チョッパ回Ｂ３は、コイルとスイッチング素子とダ
イオードを用いて構成され、前記全波整流回路２の出力
電圧をスイッチングによって昇圧して平滑コンデンサ４
に導出する。平滑コンデンサ４からの直流電圧はインバ
ータ回路５でスイッチングを受け、高周波パルスとなり
、電流制限用コイル６を介して放電灯８の一端に加えら
れる。コイル６の一端と基準電位点間には共振コンデン
サ７が接続している。放電灯８の一端と電圧・周波数変
換回路９の入力間には、制御回路１０が接続されている
。That is, the full-wave rectifier circuit 2 performs full-wave rectification on the alternating current of the single-phase AC power supply 11 and supplies the rectified current to the boost chopper circuit 3 . This step-up chopper circuit B3 is configured using a coil, a switching element, and a diode, and boosts the output voltage of the full-wave rectifier circuit 2 by switching and transfers the output voltage of the full-wave rectifier circuit 2 to the smoothing capacitor 4.
It is derived as follows. The DC voltage from the smoothing capacitor 4 undergoes switching in the inverter circuit 5, becomes a high frequency pulse, and is applied to one end of the discharge lamp 8 via the current limiting coil 6. A resonant capacitor 7 is connected between one end of the coil 6 and a reference potential point. A control circuit 10 is connected between one end of the discharge lamp 8 and an input of the voltage/frequency conversion circuit 9.
制御回路１０は、放電灯８の一端と基準電位点間に、ダ
イオード１３と抵抗１４．１５を直列接続して成る放電
灯端子電圧検出回路と、基２に電圧源ＶＯと基準電位点
間に、抵抗１６．１７を直列接続して成る基準電圧発生
回路と、前記抵抗１７に並列接続して前記基準電圧発生
回路の出力に時定数（遅れ）を持たせるための時定数コ
ンデンサ１８と、反転入力端に抵抗１４．１５の接続点
における検出電圧が入力され、非反転入力端にコンデン
サ１８の時定数を伴った基準電圧が入力される誤差アン
プ１９と、この誤差アンプ１９の出力端子と電圧・周波
数変換回路９の入力端子間に接続し、始動時のように管
端の検出電圧が基準電圧を越える時のみ誤差アンプ１９
の出力を電圧・周波数変換回路９に伝えるためのダイオ
ード２０とから構成されている。なお、放電灯８の両端
のフィラメント間には始動用のコンデンサ１２が直列に
接続されている。The control circuit 10 includes a discharge lamp terminal voltage detection circuit formed by connecting a diode 13 and a resistor 14.15 in series between one end of the discharge lamp 8 and a reference potential point, and a discharge lamp terminal voltage detection circuit formed by connecting a diode 13 and a resistor 14.15 in series between one end of the discharge lamp 8 and a reference potential point. , a reference voltage generating circuit formed by connecting resistors 16 and 17 in series, a time constant capacitor 18 connected in parallel to the resistor 17 for giving a time constant (delay) to the output of the reference voltage generating circuit, and an inverting circuit. An error amplifier 19 has an input terminal to which the detected voltage at the connection point of the resistor 14.15 is input, and a non-inverting input terminal to which a reference voltage with a time constant of the capacitor 18 is input, and an output terminal of this error amplifier 19 and a voltage・Connected between the input terminals of the frequency conversion circuit 9, the error amplifier 19 is used only when the detected voltage at the tube end exceeds the reference voltage, such as during startup.
and a diode 20 for transmitting the output to the voltage/frequency conversion circuit 9. Note that a starting capacitor 12 is connected in series between the filaments at both ends of the discharge lamp 8.
更に、電圧・周波数変換回路９の入力端には始動時の周
波数制御を行う制御回路１０のほかに通常の点灯時に放
電灯８に流れる電流を検出し該電圧を一定とするよう周
波数制御を行う図示しない制御回路（誤差アンプ２１を
含む）が接続されている。この制御回路の構成は、制御
回路１ｏとほぼ同様の構成であるが、誤差アンプ２１に
供給する基準電圧が、通常の点灯時のランプ電流を制御
するのに適した電圧値に設定されている。Further, at the input terminal of the voltage/frequency conversion circuit 9, in addition to a control circuit 10 that performs frequency control during startup, the current flowing through the discharge lamp 8 during normal lighting is detected and frequency control is performed to keep the voltage constant. A control circuit (not shown) (including error amplifier 21) is connected. The configuration of this control circuit is almost the same as that of the control circuit 1o, but the reference voltage supplied to the error amplifier 21 is set to a voltage value suitable for controlling the lamp current during normal lighting. .
このような構成において、始動時、電源スィッチＳＷが
投入されると、全波整流回路２．昇圧チョッパ回路３．
平滑コンデンサ４を介してインバータ回路５に電圧が供
給される。この電源スイッチＳＷ投入と同時に、基準電
圧源ＶＯにも電源電圧が供給される。電源投入後、電圧
・周波数変換回路９が動作し、インバータ回路５は所定
の周波数でスイッチングを開始するが、この時コイル６
とコンデンサ７によるＬＣ共振作用によって放電灯８に
かかる端子電圧は昇圧され、かつ放電灯８のフィラメン
トにコンデンサ１２を通して予熱電流が流れ、放電灯８
は点灯する。制御回路１ｏは、この始動時においてイン
バータ回路５のスイッチング素子に過電流が生じないよ
うに、放電灯８の端子電圧を低くするスイッチング周波
数がち発振を開始させるなめに設けられている。即ち、
放電灯８の端子電圧を抵抗１４．１５で検出して、この
検出電圧を抵抗１６．１７による基準電圧値と比較し、
前記検出電圧が基準電圧値より大きい場合は誤差アンプ
１９の出力により前記検出電圧に応じて電圧・周波数変
換回路９の入力電圧を制御し、発振周波数を上げるよう
周波数制御を行い、始動時の端子電圧を一定化する閉ル
ープ制御を行うようになっている。この場合、前述の発
振開始の制御は、誤差アンプ１９の非反転入力端にＣＲ
遅れ時定数を伴った基準電圧を印加するようにして行い
、電源投入時は放電灯８の端子電圧が徐々に上がるよう
にしている。これは、インバータ回路５のスイッチング
周波数と、コイル６とコンデンサ７によるＬＣ共振周波
数とをずらすよう周波数制御を行えばＬＣ共振回路の出
力電圧（即ち、放電灯８の端子電圧）を制御できるため
である。In such a configuration, when the power switch SW is turned on at startup, the full-wave rectifier circuit 2. Boost chopper circuit 3.
Voltage is supplied to the inverter circuit 5 via the smoothing capacitor 4. At the same time as this power switch SW is turned on, the power supply voltage is also supplied to the reference voltage source VO. After the power is turned on, the voltage/frequency conversion circuit 9 operates, and the inverter circuit 5 starts switching at a predetermined frequency.
The terminal voltage applied to the discharge lamp 8 is boosted by the LC resonance effect of the capacitor 7, and a preheating current flows through the filament of the discharge lamp 8 through the capacitor 12.
lights up. The control circuit 1o is provided to start oscillation at a switching frequency that lowers the terminal voltage of the discharge lamp 8 so that an overcurrent does not occur in the switching elements of the inverter circuit 5 at the time of starting. That is,
The terminal voltage of the discharge lamp 8 is detected by a resistor 14.15, and this detected voltage is compared with the reference voltage value by a resistor 16.17.
When the detected voltage is larger than the reference voltage value, the output of the error amplifier 19 controls the input voltage of the voltage/frequency conversion circuit 9 according to the detected voltage, and frequency control is performed to increase the oscillation frequency, so that the terminal at the time of starting is controlled. It uses closed-loop control to keep the voltage constant. In this case, the above-mentioned oscillation start control is performed by applying a CR to the non-inverting input terminal of the error amplifier 19.
This is done by applying a reference voltage with a delay time constant, so that the terminal voltage of the discharge lamp 8 gradually increases when the power is turned on. This is because the output voltage of the LC resonance circuit (i.e., the terminal voltage of the discharge lamp 8) can be controlled by performing frequency control to shift the switching frequency of the inverter circuit 5 and the LC resonance frequency of the coil 6 and capacitor 7. be.
しかしながら、電源スィッチＳＷを切って直ぐにまた投
入するような場合（或いは、電源スィッチＳＷを短い周
期でオン、オフする場合）に、時定数コンデンサ１８の
充電電荷が放電しきれないまま再び基準電圧源ＶＤが投
入されるため、始動時放電灯８の端子電圧が徐々に上昇
せず、所謂ソフトスタートにならないと共に、インバー
タ回路のスイッチング素子が過電流になるという問題が
あった。However, when the power switch SW is turned off and then turned on again (or when the power switch SW is turned on and off in short cycles), the reference voltage source may be turned on again before the charge in the time constant capacitor 18 is fully discharged. Since VD is turned on, the terminal voltage of the discharge lamp 8 does not gradually rise during startup, so there is a problem that a so-called soft start does not occur and the switching elements of the inverter circuit become overcurrent.
（発明が解決しようとする課題）
上記の如く、従来の放電灯点灯回路では、電源を切って
直ぐにまた入れるような場合に、時定数コンデンサの充
電電荷が放電しきれないままスタートしてしまい、ソフ
トスタートにならないと共に、スイッチング素子が過電
流になるという問題があった。(Problem to be Solved by the Invention) As described above, in the conventional discharge lamp lighting circuit, when the power is turned off and then turned on again, the circuit starts before the charge in the time constant capacitor is fully discharged. There was a problem that soft start could not be achieved and the switching element would receive overcurrent.
そこで、本発明はこのような問題に鑑み、電源スィッチ
を切って直ぐに入れるような場合でも、時定数コンデン
サの電荷を速やかに放電して、スイッチング素子の過電
流を防止しかつソフトスタートを可能とする放電灯点灯
装置を提供することを目的とするものである。In view of these problems, the present invention has been developed to quickly discharge the charge in the time constant capacitor even when the power switch is turned off and then turned on again, thereby preventing overcurrent in the switching element and enabling soft start. An object of the present invention is to provide a discharge lamp lighting device.
［発明の構成］
（課題を解決するための手段）
本発明は、直流電圧を、発振周波数が制御電圧によって
制御される発振手段からの周波数でスイッチングするこ
とにより、交流電圧に変換するインバータ回路と、
このインバータ回路と放電灯間に設けられる電流制限用
コイルと共振コンデンサからなる共振手段であって、前
記インバータ回路からの交流電圧を放電灯に印加する際
に、ＬＣ共振作用を利用して始動時に放電灯に印加され
る電圧を高める昇圧手段と、
放電灯の端子電圧を検出し、該検出電圧を比較手段にて
基準電圧と比較し、該検出電圧が基準電圧を越えた時に
該検出電圧に応じて前記発振手段の周波数を変化させ、
始動時の放電灯端子電圧を一定化する閉ループ制御を行
う手段であって、前記比較手段の基準電圧入力端に時定
数コンデンサを接続して、始動時に時定数を持って立ち
上がる基準電圧を印加することより、放電灯端子電圧を
低い値からスタートさせるよう制御する制御手段とを具
備した放電灯点灯装置において、前記比較手段の基準電
圧入力端とその出力端間に、前記交流電源のオフ時に前
記比較手段の時定数コンデンサの充電電荷を該比較手段
を通して放電させるダイオードを設けたことを特徴とす
るものである。[Structure of the Invention] (Means for Solving the Problems) The present invention provides an inverter circuit that converts a DC voltage into an AC voltage by switching the oscillation frequency at a frequency from an oscillation means controlled by a control voltage. , a resonance means consisting of a current limiting coil and a resonant capacitor provided between the inverter circuit and the discharge lamp, which starts by utilizing the LC resonance effect when applying the AC voltage from the inverter circuit to the discharge lamp. a step-up means for increasing the voltage applied to the discharge lamp; a voltage booster for detecting the terminal voltage of the discharge lamp; comparing the detected voltage with a reference voltage; and when the detected voltage exceeds the reference voltage; changing the frequency of the oscillation means according to;
Means for performing closed-loop control to constantize the terminal voltage of the discharge lamp at the time of starting, wherein a time constant capacitor is connected to the reference voltage input terminal of the comparison means, and a reference voltage that rises with a time constant at the time of starting is applied. In particular, in a discharge lamp lighting device comprising a control means for controlling the discharge lamp terminal voltage to start from a low value, the voltage is applied between the reference voltage input terminal of the comparison means and its output terminal when the AC power source is turned off. The present invention is characterized in that a diode is provided for discharging the charge of the time constant capacitor of the comparison means through the comparison means.
以上の構成に加えて、前記発振手段の入力端が、前記制
御手段における比較手段以外の、他の発振制御手段とダ
イオード・オア接続されることにより、より一層確実に
時定数コンデンサの電荷を放電させることができる。In addition to the above configuration, the input terminal of the oscillation means is diode-OR connected to other oscillation control means other than the comparison means in the control means, thereby discharging the charge of the time constant capacitor more reliably. can be done.
（作用）
このような構成によれば、電源オフと同時に、時定数コ
ンデンサの充電電荷が放電用ダイオード及び比較手段を
通して速やかに放電されるので、電源をオフにして直ぐ
にまたオンにするような場合でも、インバータ回路のス
イッチング素子に過電流を生じることなく、常にソフト
スタートできる。(Function) According to this configuration, the charge in the time constant capacitor is quickly discharged through the discharging diode and the comparison means at the same time as the power is turned off, so when the power is turned off and then turned on again immediately. However, soft start is always possible without causing overcurrent to the switching elements of the inverter circuit.
（実施例） 実施例について図面を参照して説明する。(Example) Examples will be described with reference to the drawings.
第１図は本発明の一実施例の放電灯点灯装置を示す回路
図である。FIG. 1 is a circuit diagram showing a discharge lamp lighting device according to an embodiment of the present invention.
第１図において、第２図と同一部分には同符号を付して
説明する０本実施例の放電灯点灯装置１０Ａで、全波整
流回路２、昇圧チョッパ回路３、平滑コンデンサ４、イ
ンバータ回路５、電流制限用コイル６、共振コンデンサ
７、放電灯８、電圧・周波数変換回路９、単相交流電源
１１、始動用コンデンサ１２は第２図と同様である０本
実施例が第２図と異なる点は、制御回路１０Ａの構成で
ある。即ち、制御回路１０Ａは、従来と同様に、放電灯
８の一端と基準電位点間に、ダイオード１３と抵抗１４
．１５を直列接続して成る放電灯端子電圧検出回路と、
基準電圧源ＶＤと基準電位点間に、抵抗１６．１７を直
列接続して成る基準電圧発生回路と、前記抵抗１７に並
列接続して前記基準電圧発生回路の出力に時定数〈遅れ
）を持たせるための時定数コンデンサ１８と、前記抵抗
１４．１５の接続点における検出電圧が反転入力端に入
力され、非反転入力端にコンデンサ１８の時定数を伴っ
た基準電圧が入力される誤差アンプ１９と、この誤差ア
ンプ１９の出力端子と電圧・周波数変換回路９の入力端
子間に接続し、始動時のように管端の検出電圧が基準電
圧を越える時のみ誤差アンプ１９の出力を電圧用変換回
路９に伝えるためのダイオード２０とを備えているが、
更に本実施例では誤差アンプ１９の非反転入力端とダイ
オード２０のアノード（即ち、電圧・周波数変換回路９
の入力端）間に、アノード側を誤差アンプ１９の非反転
入力端に接続するように放電用のダイオード２２を設け
た構成とするものである。In FIG. 1, parts that are the same as those in FIG. 5. The current limiting coil 6, resonant capacitor 7, discharge lamp 8, voltage/frequency conversion circuit 9, single-phase AC power supply 11, and starting capacitor 12 are the same as those shown in Figure 2. The difference is the configuration of the control circuit 10A. That is, the control circuit 10A includes a diode 13 and a resistor 14 between one end of the discharge lamp 8 and the reference potential point, as in the conventional case.
．． 15 connected in series, a discharge lamp terminal voltage detection circuit;
A reference voltage generation circuit consisting of a resistor 16 and 17 connected in series between a reference voltage source VD and a reference potential point, and a time constant (delay) in the output of the reference voltage generation circuit connected in parallel to the resistor 17. An error amplifier 19 receives the detection voltage at the connection point between the time constant capacitor 18 and the resistor 14.15 at its inverting input terminal, and receives the reference voltage with the time constant of the capacitor 18 at its non-inverting input terminal. The output terminal of the error amplifier 19 is connected between the output terminal of the voltage/frequency conversion circuit 9 and the input terminal of the voltage/frequency conversion circuit 9, and the output of the error amplifier 19 is converted to voltage only when the detected voltage at the tube end exceeds the reference voltage, such as during startup. It is equipped with a diode 20 for transmitting information to the circuit 9,
Furthermore, in this embodiment, the non-inverting input terminal of the error amplifier 19 and the anode of the diode 20 (i.e., the voltage/frequency conversion circuit 9
A discharging diode 22 is provided between the input terminals of the error amplifier 19 so that its anode side is connected to the non-inverting input terminal of the error amplifier 19.
このようにダイオード２２を接続することにより、電源
スィッチＳＷをオンからオフにした時、時定数コンデン
サ１８の充ｉｔ荷をダイオード２０及び誤差アンプ１９
を通して速やかに放電させることができるので、再び直
ぐに電源スイ・ｙチＳＷをオンした場合でも、基準電圧
を時定数を持って立上げることができ、始動時は常に、
放電灯８の端子電圧を徐々に上げるソフトスタートを行
うことができる。その他の作用、効果は第２図の従来例
と同様である。By connecting the diode 22 in this way, when the power switch SW is turned off from on, the charge of the time constant capacitor 18 is transferred to the diode 20 and the error amplifier 19.
Even if you turn on the power switch immediately again, the reference voltage can be raised with a time constant.
A soft start can be performed to gradually increase the terminal voltage of the discharge lamp 8. Other functions and effects are similar to those of the conventional example shown in FIG.
なお、この放電用ダイオード２２のカソード側を基準電
圧源ＶＤに接続する方法も考えられるが、基準電圧源Ｖ
Ｄの内部には平滑コンデンサを有しているので、このよ
うな接続方法では速やかに放電することは不可能である
。Note that a method of connecting the cathode side of this discharge diode 22 to the reference voltage source VD is also considered;
Since D has a smoothing capacitor inside, it is impossible to discharge quickly with this connection method.
更に、通常、電圧・周波数変換回路９の入力端には始動
時の周波数制御を行う制御回路１０Ａのほかに通常点灯
時に放電灯８の端子電圧を検出し該電圧を一定とするよ
う周波数制御を行う図示しない制御回路（誤差アンプ２
１を含む）が接続されているので１．誤差アンプ２１の
出力端に図示の如くダイオード２３を挿入することによ
り、時定数コンデンサ１８の充電電荷を誤差アンプ１９
だけでなく誤差アンプ２１をも通して放電させることが
できる。これにより、より一層確実に電荷を放電させる
ことができる。Further, normally, at the input terminal of the voltage/frequency conversion circuit 9, in addition to a control circuit 10A that performs frequency control during startup, there is also a control circuit 10A that detects the terminal voltage of the discharge lamp 8 during normal lighting and performs frequency control to keep the voltage constant. A control circuit (not shown) (error amplifier 2)
1) are connected, so 1. By inserting a diode 23 as shown in the figure at the output terminal of the error amplifier 21, the charge charged in the time constant capacitor 18 is transferred to the error amplifier 19.
In addition to this, it can also be discharged through the error amplifier 21. Thereby, charges can be discharged more reliably.
［発明の効果］
以上述べたように本発明によれば、始動時の放電灯端子
電圧を一定化すべく制御する閉ループ制御回路の基準電
圧に、始動時、時定数を持たせる場合（即ち、ソフトス
タートさせようとする場合）に、電源スィッチを切って
直ぐに入れても、電源オフと同時に時定数コンデンサの
充電電荷を速やかに放電できるので、再び電源オンした
時にスイッチング素子に過電流を生じるのを防止できる
と共に、常にソフトスタートさせることができる。[Effects of the Invention] As described above, according to the present invention, when the reference voltage of the closed loop control circuit that controls the discharge lamp terminal voltage at the time of startup to be constant has a time constant at the time of startup (i.e., the software Even if you turn off the power switch and then turn it on right away, the charge in the time constant capacitor can be quickly discharged at the same time as the power is turned off, which prevents overcurrent from occurring in the switching element when the power is turned on again. This can be prevented and a soft start can always be performed.
第１図は本発明の一実施例の放電灯点灯装置を示す回路
図、第２図は従来の放電灯点灯装置を示す回路図である
。
５・・・インバータ回路、６・・・電流制限用コイル、
７・・・共振コンデンサ、８・・・放電灯、９・・・電
圧・周波数変換回路、
１０Ａ・・・制御回路、１４〜１７・・・抵抗、１８・
・・時定数コンデンサ、
１９．２１・・・誤差アンプ、
２０．２２．２３・・・ダイオード、
ＶＤ・・・基準電圧源、ＳＷ・・・電源スィッチ。FIG. 1 is a circuit diagram showing a discharge lamp lighting device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional discharge lamp lighting device. 5... Inverter circuit, 6... Current limiting coil,
7... Resonance capacitor, 8... Discharge lamp, 9... Voltage/frequency conversion circuit, 10A... Control circuit, 14-17... Resistor, 18...
...Time constant capacitor, 19.21...Error amplifier, 20.22.23...Diode, VD...Reference voltage source, SW...Power switch.
Claims (2)
される発振手段からの周波数でスイッチングすることに
より、交流電圧に変換するインバータ回路と、 このインバータ回路と放電灯間に設けられる電流制限用
コイルと共振コンデンサからなる共振手段であって、前
記インバータ回路からの交流電圧を放電灯に印加する際
に、ＬＣ共振作用を利用して始動時に放電灯に印加され
る電圧を高める昇圧手段と、 放電灯の端子電圧を検出し、該検出電圧を比較手段にて
基準電圧と比較し、該検出電圧が基準電圧を越えた時に
該検出電圧に応じて前記発振手段の周波数を変化させ、
始動時の放電灯端子電圧を一定化する閉ループ制御を行
う手段であつて、前記比較手段の基準電圧入力端に時定
数コンデンサを接続して、始動時に時定数を持って立ち
上がる基準電圧を印加することより、放電灯端子電圧を
低い値からスタートさせるよう制御する制御手段とを具
備した放電灯点灯装置において、 前記比較手段の基準電圧入力端とその出力端間に、前記
交流電源のオフ時に前記比較手段の時定数コンデンサの
充電電荷を該比較手段を通して放電させるダイオードを
設けたことを特徴とする放電灯点灯装置。(1) An inverter circuit that converts a DC voltage into an AC voltage by switching the oscillation frequency at a frequency from an oscillation means controlled by a control voltage, and a current limiter provided between the inverter circuit and the discharge lamp. a resonant means comprising a resonant coil and a resonant capacitor, and a booster means for increasing the voltage applied to the discharge lamp at the time of starting by utilizing LC resonance effect when applying the alternating current voltage from the inverter circuit to the discharge lamp; , detecting the terminal voltage of the discharge lamp, comparing the detected voltage with a reference voltage by a comparing means, and changing the frequency of the oscillating means according to the detected voltage when the detected voltage exceeds the reference voltage;
Means for performing closed-loop control to constantize the terminal voltage of the discharge lamp at the time of starting, wherein a time constant capacitor is connected to the reference voltage input terminal of the comparison means, and a reference voltage that rises with a time constant at the time of starting is applied. In particular, in a discharge lamp lighting device comprising a control means for controlling the discharge lamp terminal voltage to start from a low value, the voltage is applied between the reference voltage input terminal of the comparison means and its output terminal when the AC power source is turned off. A discharge lamp lighting device comprising a diode for discharging the charge of a time constant capacitor of a comparison means through the comparison means.
比較手段以外の、他の発振制御手段とダイオード・オア
接続されていることを特徴とする請求項１記載の放電灯
点灯装置。(2) The discharge lamp lighting device according to claim 1, wherein the input terminal of the oscillation means is diode-OR connected to another oscillation control means other than the comparison means in the control means.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2261975A JPH04141989A (en) | 1990-09-29 | 1990-09-29 | Discharge lamp lighting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2261975A JPH04141989A (en) | 1990-09-29 | 1990-09-29 | Discharge lamp lighting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04141989A true JPH04141989A (en) | 1992-05-15 |
Family
ID=17369263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2261975A Pending JPH04141989A (en) | 1990-09-29 | 1990-09-29 | Discharge lamp lighting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04141989A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4900507A (en) * | 1987-05-05 | 1990-02-13 | Westinghouse Electric Corp. | Nuclear fuel assembly debris filter bottom nozzle |
-
1990
- 1990-09-29 JP JP2261975A patent/JPH04141989A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4900507A (en) * | 1987-05-05 | 1990-02-13 | Westinghouse Electric Corp. | Nuclear fuel assembly debris filter bottom nozzle |
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