JP3404083B2 - Discharge lamp lighting device - Google Patents
Discharge lamp lighting deviceInfo
- Publication number
- JP3404083B2 JP3404083B2 JP20744093A JP20744093A JP3404083B2 JP 3404083 B2 JP3404083 B2 JP 3404083B2 JP 20744093 A JP20744093 A JP 20744093A JP 20744093 A JP20744093 A JP 20744093A JP 3404083 B2 JP3404083 B2 JP 3404083B2
- Authority
- JP
- Japan
- Prior art keywords
- discharge lamp
- voltage
- feedback control
- idle period
- detection unit
- 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.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、放電灯点灯装置に係
り、特に、バックライト用インバータのように安全性を
要求される点灯装置に関する。
【０００２】
【従来の技術】従来の装置は、放電灯の故障などによる
不点灯状態の時に、放電灯点灯装置が発熱するという問
題があった。
【０００３】
【発明が解決しようとする課題】従来の放電灯点灯装置
では、不点灯状態の時に発熱するという問題があった。
【０００４】本発明の目的は、放電灯電流が帰還されな
いときに、発熱することのない点灯装置を提供すること
にある。
【０００５】
【課題を解決するための手段】上記目的は、電流が帰還
されないときに、時定数設定回路により時間を遅らせた
後、休止期間調整器に電圧をかけることで達成できる。
【０００６】
【作用】放電灯電流が帰還されないと、トランジスタが
停止し、時定数設定回路により時間を遅らせた後、休止
期間調整器に電圧がかかり、帰還制御ＩＣの出力を停止
させる。これより、点灯装置の不点灯時の発熱がなくな
る。
【０００７】
【実施例】図１に本発明の一実施例の回路図を示す。電
源電圧Ｖｉｎはチョッパ回路１に入力され、調光命令に
応じたチョッピング電圧出力Ｖｃｏｎｔを出力する。Ｄ
Ｃ／ＡＣコンバータ２はトランスで昇圧された交流電圧
を発生し、放電灯３を点灯させる。この時、放電灯電流
は放電灯電流検出部４によって検出され、値を帰還制御
ＩＣ５に入力し、指令値とあわないときはＶｃｏｎｔ出
力を変化させ、指令値にあうように制御する。
【０００８】従来の構成では、放電灯の故障などによる
不点灯状態の時に、放電灯電流が帰還されないため帰還
制御ＩＣには値が入力されず、Ｖｃｏｎｔ出力を最大に
してしまうため、トランスに長時間高電圧がかかってし
まい、トランスが発熱した。
【０００９】本発明では、放電灯電流が帰還されないと
トランジスタ６が停止し、時定数設定回路７により時間
を遅らせた後、休止期間調整器８に電圧がかかり、帰還
制御ＩＣ５の出力が停止するためトランスに高電圧がか
からなくなり、トランスの発熱がなくなる。
【００１０】
【発明の効果】本発明によれば、放電灯の故障などによ
る不点灯状態の時に、発熱のない放電灯点灯装置を提供
することができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device for a discharge lamp, and more particularly to a lighting device requiring safety such as an inverter for a backlight. 2. Description of the Related Art The conventional apparatus has a problem that the discharge lamp lighting device generates heat when it is in a non-lighting state due to a failure of the discharge lamp or the like. The conventional discharge lamp lighting device has a problem that heat is generated when the lamp is not lit. An object of the present invention is to provide a lighting device that does not generate heat when the discharge lamp current is not fed back. The above object can be attained by applying a voltage to the idle period adjuster after the time is set back by the time constant setting circuit when no current is fed back. If the discharge lamp current is not fed back, the transistor is stopped, the time is delayed by the time constant setting circuit, and then the voltage is applied to the idle period adjuster to stop the output of the feedback control IC. This eliminates heat generation when the lighting device is not lit. FIG. 1 is a circuit diagram showing an embodiment of the present invention. The power supply voltage Vin is input to the chopper circuit 1 and outputs a chopping voltage output Vcont according to the dimming command. D
The C / AC converter 2 generates an AC voltage boosted by a transformer, and turns on the discharge lamp 3. At this time, the discharge lamp current is detected by the discharge lamp current detection unit 4 and the value is input to the feedback control IC 5. If the discharge lamp current does not match the command value, the Vcont output is changed to perform control so as to match the command value. In the conventional configuration, when the lamp is not lit due to a failure of the discharge lamp, the discharge lamp current is not fed back, so that no value is input to the feedback control IC, and the Vcont output is maximized. High voltage was applied for a long time and the transformer generated heat. According to the present invention, when the discharge lamp current is not fed back, the transistor 6 stops, the time is set by the time constant setting circuit 7, and then the voltage is applied to the idle period adjuster 8, so that the output of the feedback control IC 5 stops. Therefore, a high voltage is not applied to the transformer, and the transformer does not generate heat. According to the present invention, it is possible to provide a discharge lamp lighting device that does not generate heat when it is in an unlit state due to a failure of the discharge lamp or the like.
【図面の簡単な説明】
【図１】本発明の実施例の回路図。
【符号の説明】
１…チョッパ回路、２…ＤＣ／ＡＣコンバータ、３…放
電灯、４…放電灯電流検出部、５…帰還制御ＩＣ、６…
トランジスタ、７…時定数設定回路、８…休止期間調整
器、９…誤差増幅器、１０…比較器。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of an embodiment of the present invention. [Description of Signs] 1 ... Chopper circuit, 2 ... DC / AC converter, 3 ... Discharge lamp, 4 ... Discharge lamp current detector, 5 ... Feedback control IC, 6 ...
Transistor, 7: time constant setting circuit, 8: idle period adjuster, 9: error amplifier, 10: comparator.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H05B 41/24 H05B 41/282 ──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. 7 , DB name) H05B 41/24 H05B 41/282
Claims (1)
れ、その出力VcontがDC/ACコンバータ(2)に入力され、
その出力である交流電圧が放電灯(3)の一端の電極に印
加され、前記放電灯(3)の他端の電極が放電灯電流検出
部(4)に接続されることにより前記放電灯を流れる電流
が前記放電灯電流検出部(4)で検出され、 前記放電灯電流検出部(4)においては前記放電灯(3)を流
れる電流を整流して正の値のみを出力し、その出力を前
記放電灯電流検出部(4)内の第１、第２の直列抵抗に流
して分圧し、前記放電灯電流値に応じた電圧値を帰還制
御IC(5)内の誤差増幅器(9)に出力し、前記放電灯(3)が
点灯しているときは前記放電灯電流値を所定に保つよう
に前記帰還制御IC(5)の比較器(10)から前記チョッパ回
路(1)へ帰還をかけ、 前記分圧した出力端と前記誤差増幅器(9)とは電気的に
接続され、その出力端と前記誤差増幅器(9)との間には
トランジスタ(6)のベースが接続され、他の一の端子は
接地され、その他の一の端子は前記帰還制御IC(5)内の
休止期間調整器(8)に接続され、前記その他の一の端子
と前記休止期間調整器(8)との間には時定数調整回路(7)
が設けられ、 前記放電灯(3)が点灯しているときは前記トランジスタ
(6)は導通状態となり、前記放電灯(3)が不点灯のときは
前記トランジスタ(6)は停止し、前記時定数調整回路(7)
により時間を遅らせた後、前記休止期間調整器(8)に電
圧がかかり、前記誤差増幅器(9)の入力はない状態とな
ることに基づいて前記休止期間調整器(8)と前記誤差増
幅器(9)とが入力される前記比較器(10)の出力は前記帰
還制御IC(5)を停止して前記チョッパ回路(1)を停止させ
るように構成されたことを特徴とする放電灯点灯装置。(57) [Claims] [Claim 1] A power supply voltage Vin is input to a chopper circuit (1), and an output Vcont is input to a DC / AC converter (2),
The output AC voltage is applied to an electrode at one end of the discharge lamp (3), and the electrode at the other end of the discharge lamp (3) is connected to a discharge lamp current detection unit (4) to switch the discharge lamp. The flowing current is detected by the discharge lamp current detection unit (4), and the discharge lamp current detection unit (4) rectifies the current flowing through the discharge lamp (3) and outputs only a positive value. Is passed through the first and second series resistors in the discharge lamp current detection unit (4) to divide the voltage, and a voltage value according to the discharge lamp current value is supplied to the error amplifier (9) in the feedback control IC (5). When the discharge lamp (3) is lit, the comparator (10) of the feedback control IC (5) returns to the chopper circuit (1) so as to maintain the discharge lamp current value at a predetermined value. The divided output terminal and the error amplifier (9) are electrically connected to each other.
The base of the transistor (6) is connected between the output terminal and the error amplifier (9) , the other terminal is grounded, and the other terminal is the feedback control IC (5). Is connected to the idle period adjuster (8), and a time constant adjusting circuit (7) is provided between the other terminal and the idle period adjuster (8).
When the discharge lamp (3) is lit, the transistor
(6) becomes conductive, and when the discharge lamp (3) is not lit, the transistor (6) stops, and the time constant adjusting circuit (7)
After the time is delayed, a voltage is applied to the idle period adjuster (8), and the idle period adjuster (8) and the error amplifier ( Discharge lamp lighting device, wherein the output of the comparator (10) to which (9) is input is configured to stop the feedback control IC (5) and stop the chopper circuit (1). .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20744093A JP3404083B2 (en) | 1993-08-23 | 1993-08-23 | Discharge lamp lighting device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20744093A JP3404083B2 (en) | 1993-08-23 | 1993-08-23 | Discharge lamp lighting device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0765972A JPH0765972A (en) | 1995-03-10 |
| JP3404083B2 true JP3404083B2 (en) | 2003-05-06 |
Family
ID=16539809
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20744093A Expired - Lifetime JP3404083B2 (en) | 1993-08-23 | 1993-08-23 | Discharge lamp lighting device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3404083B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009040874A1 (en) * | 2007-09-28 | 2009-04-02 | Fujitsu Limited | Method for controlling cold-cathode tube in lighting apparatus, lighting apparatus, and liquid crystal display |
-
1993
- 1993-08-23 JP JP20744093A patent/JP3404083B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0765972A (en) | 1995-03-10 |
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