EP0804052A2 - Circuit de commande pour une lampe à décharge - Google Patents

Circuit de commande pour une lampe à décharge Download PDF

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Publication number
EP0804052A2
EP0804052A2 EP97106831A EP97106831A EP0804052A2 EP 0804052 A2 EP0804052 A2 EP 0804052A2 EP 97106831 A EP97106831 A EP 97106831A EP 97106831 A EP97106831 A EP 97106831A EP 0804052 A2 EP0804052 A2 EP 0804052A2
Authority
EP
European Patent Office
Prior art keywords
lamp
control
luminance
control according
cold cathode
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.)
Withdrawn
Application number
EP97106831A
Other languages
German (de)
English (en)
Other versions
EP0804052A3 (fr
Inventor
Martin Dipl.-Ing. Kurz
Helmut Dipl.-Ing. Habel
Thomas Dipl.-Ing. Eberharter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Original Assignee
Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH filed Critical Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH
Publication of EP0804052A2 publication Critical patent/EP0804052A2/fr
Publication of EP0804052A3 publication Critical patent/EP0804052A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
    • H05B41/3922—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations and measurement of the incident light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
    • H05B41/3927—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by pulse width modulation

Definitions

  • the invention relates to a control of cold cathode lamps, which adjusts the luminance of the lamp as closely as possible to a predetermined value, regardless of the ambient and installation conditions, or which enables the largest possible dimming range while protecting the lamp at the same time.
  • Cold cathode lamps are to be understood as complex components and have a piecewise negative current-voltage characteristic.
  • the luminance and the voltage required to ignite the tube have a large temperature dependency, the life of the lamp decreasing at high ignition voltages.
  • Various possibilities are known for controlling gas discharge lamps (see, for example, patents US 4,920,474, E-0 537 394, US 5,309,350, E-0 058 035, E-0 023 263).
  • the usual version is a resonance converter in a push-pull configuration.
  • Scatter transformers isolated DC controls or so-called “Alternating DC” controls are also known. Scatter transformers are used in high-performance applications, but have the disadvantages of poor efficiency, large design and large input reactive power, considerable noise, and they are difficult to dim.
  • DC controls significantly reduce the lamp life and are mainly used in the laboratory.
  • a better method is the "Alternating DC" control, in which the life of the lamp is not worsened, but there are disadvantages here due to the complex or slow switching of the high voltage and also when dimming, since high-voltage sources with high source impedance are fundamentally difficult to implement.
  • Resonance converters are inexpensive and widespread solutions, whereby the dimmability is possible within small limits by changing the supply voltage.
  • the dimming range can be improved by pulse width modulation and additional current feedback, the largest adjustment range is achieved by pulse packet modulation. Since the lamp is operated continuously with pulse width modulation, the ignition voltage is rarely required and the primary current consumption has low peaks, which means that the lamp and the components used are protected. Furthermore, in this operating mode, a change in the input voltage of the resonance converter can be compensated for by varying the pulse width.
  • the minimum dimming state is determined by the limit amplitude of the lamp current, which results in a minimum possible rms value at which the plasma excited during the ignition process is extinguished, whereby parasitic capacitances against housing parts or other potentials can also only partially excite the gas.
  • the lamp is ignited periodically, the system consisting of a resonance converter with a lamp as an integral component being kept in resonance by a pulse packet during the on-time and decaying after the excitation is switched off at the system's own resonance frequency.
  • the effective value of the lamp current and thus also the emitted luminance can thus be set lower than in the case of pulse width modulation.
  • an oscillator which is in resonance by definition has the lowest losses, although through the periodic ignition, which must be at least 50 Hz, the lamp is subjected to greater stress.
  • the control described in Figure 1 consists of a resonance converter supplied with DC voltage with at least one series connection of reactance 3 and cold cathode lamp 4 in the load circuit and a component referred to below as a control part, which either consist only of controller 2 or additionally interface 1 and / or measured value acquisition 5 included can, the interface being used for communication with the environment, by means of which both setpoint values can be set externally and other parameters, such as the ambient brightness E a, can be detected, thereby enabling the control loop to be adapted to static or changing conditions. Since the luminance of the lamp is strongly dependent on the temperature at a constant current (FIG.
  • the measured value acquisition 5 determines a correction factor which depends on the lamp temperature, which naturally also takes into account the ambient temperature T a , and which determines the current determined by the controller 2 in changed the extent that the predetermined luminance is achieved as accurately as possible. Since the self-heating of the cold cathode tube takes place at a defined lamp current according to a lamp-specific time constant, the lamp temperature can not only be measured but also calculated. The determination of the lamp temperature also makes it possible to detect excess temperatures of the lamp caused by malfunctions and to initiate suitable countermeasures.
  • the lamp current is set in such a way that the measured luminance corresponds to the target value and thus temperature and aging effects relating to the luminance are compensated.
  • the output stage 3 of the present invention is preferably designed as a resonance converter, the current is controlled by varying the amplitude and / or the pulse duty factor (pulse width and / or pulse packet modulation), with a direct ⁇
  • An optimization of the dimming range and the life of the lamp can be achieved by alternative selection of pulse width and pulse packet modulation depending on the lamp current and / or the luminance and by reducing the amplitude of the ignition voltage to a minimum depending on the lamp temperature.
  • the lamp is operated continuously by means of pulse width modulation in the dimming range from maximum to the limit amplitude of the lamp current, at which the plasma excited during the ignition process is extinguished, followed by switching to pulse packet modulation, in which the lamp is periodically ignited with a lower effective value of the lamp current and so that the dimming range is extended downwards.
  • the output can be designed as a switched rectifier, which rectifies the output signal and periodically reverses the polarity to the lamp in order to improve the homogeneity of the luminance on the lamp surface.
  • An advantageous embodiment of the device according to the invention uses a microcontroller in which characteristic diagrams of the cold cathode lamp are stored and are used to determine the optimal lamp input parameters in order to achieve the desired luminance.
  • the microcontroller can also be used to correlate the pulse packet repetition rate with the image refresh rate supplied from the outside, as a result of which interference with LCD backlighting can be avoided.
  • a further advantageous embodiment of the device according to the invention takes into account the ambient brightness in order to adapt the luminance of the lamp to it.
  • the operating temperature of the cold cathode lamp can be optimized by an electrically adjustable external cooling, which improves the efficiency of the overall system.

Landscapes

  • Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
EP97106831A 1996-04-24 1997-04-24 Circuit de commande pour une lampe à décharge Withdrawn EP0804052A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT743/96 1996-04-24
AT74396A AT407461B (de) 1996-04-24 1996-04-24 Ansteuerung für entladungslampe

Publications (2)

Publication Number Publication Date
EP0804052A2 true EP0804052A2 (fr) 1997-10-29
EP0804052A3 EP0804052A3 (fr) 1999-04-07

Family

ID=3498638

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97106831A Withdrawn EP0804052A3 (fr) 1996-04-24 1997-04-24 Circuit de commande pour une lampe à décharge

Country Status (2)

Country Link
EP (1) EP0804052A3 (fr)
AT (1) AT407461B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10013041A1 (de) * 2000-03-17 2001-09-27 Trilux Lenze Gmbh & Co Kg Verfahren und Vorrichtung zum Betrieb einer mit einer Leuchtstofflampe versehenen Leuchte

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE202005021525U1 (de) 2004-03-30 2008-07-17 Ruppel, Stefan Lampe mit einer Kaltkathodenröhre
DE102005014857B4 (de) 2004-03-30 2010-12-23 Stefan Ruppel Leuchte, insbesondere zum Einbau in oder zum Anbau an ein Möbel oder eine Vitrine, mit einer Kaltkathodenröhre
DE202004005184U1 (de) * 2004-03-30 2005-08-18 Ruppel, Stefan Lampe mit einer Kaltkathodenröhre

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4887122A (en) * 1987-11-04 1989-12-12 Minolta Camera Kabushiki Kaisha Copying machine
EP0406116A1 (fr) * 1989-06-30 1991-01-02 Thomson-Csf Procédé et dispositif de gradation de lumière pour lampe fluorescente d'éclairage arrière d'écran à cristaux liquides
EP0477922A1 (fr) * 1990-09-25 1992-04-01 Toshiba Lighting & Technology Corporation Appareil pour le fonctionnement d'une lampe à décharge
EP0572207A2 (fr) * 1992-05-26 1993-12-01 Compaq Computer Corporation Système de régulation de l'intensité lumineuse d'un éclairage arrière d'affichage à cristaux liquides
WO1995012964A1 (fr) * 1993-11-03 1995-05-11 Science Applications International Corporation Systeme d'illumination uv par l'arriere a haute efficacite pour dispositifs d'affichage electroniques
US5428265A (en) * 1994-02-28 1995-06-27 Honeywell, Inc. Processor controlled fluorescent lamp dimmer for aircraft liquid crystal display instruments

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4087722A (en) * 1975-05-01 1978-05-02 American Ionetics, Inc. Apparatus and method for supplying power to gas discharge lamp systems
DE2927837C2 (de) * 1979-07-10 1982-09-16 Peter 7750 Konstanz Kreutzer Transistorwechselrichterschaltung
JPS57129177A (en) * 1981-02-04 1982-08-11 Toshiba Electric Equip Corp Transistor inverter
US4356432A (en) * 1981-02-25 1982-10-26 Exxon Research And Engineering Co. Solid state power switch for gas discharge lamps
US4463284A (en) * 1981-07-28 1984-07-31 Konishiroku Photo Industry Co., Ltd. Method and apparatus for controlling luminous intensity of fluorescent lamp of reproducing apparatus
FR2614748A1 (fr) * 1987-04-29 1988-11-04 Omega Electronics Sa Dispositif d'alimentation d'une lampe a decharge
US4920474A (en) * 1989-03-23 1990-04-24 North American Philips Corporation High frequency high voltage power supply with controlled output power
US5105125A (en) * 1990-08-06 1992-04-14 Yang Tai Her Device for alternating bulb polarities of a DC lighting system
JP2587718B2 (ja) * 1990-10-01 1997-03-05 株式会社小糸製作所 車輌用放電灯の点灯回路
JP3030579B2 (ja) * 1991-07-30 2000-04-10 株式会社キジマ プッシュプルインバ−タ
US5315214A (en) * 1992-06-10 1994-05-24 Metcal, Inc. Dimmable high power factor high-efficiency electronic ballast controller integrated circuit with automatic ambient over-temperature shutdown
DE4301276A1 (de) * 1993-01-19 1994-07-21 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Verfahren und Stromversorgungseinheit zum stabilisierten Betrieb einer Natrium-Hochdruckentladungslampe
JP3606909B2 (ja) * 1994-07-12 2005-01-05 三菱電機株式会社 交流放電灯点灯装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4887122A (en) * 1987-11-04 1989-12-12 Minolta Camera Kabushiki Kaisha Copying machine
EP0406116A1 (fr) * 1989-06-30 1991-01-02 Thomson-Csf Procédé et dispositif de gradation de lumière pour lampe fluorescente d'éclairage arrière d'écran à cristaux liquides
EP0477922A1 (fr) * 1990-09-25 1992-04-01 Toshiba Lighting & Technology Corporation Appareil pour le fonctionnement d'une lampe à décharge
EP0572207A2 (fr) * 1992-05-26 1993-12-01 Compaq Computer Corporation Système de régulation de l'intensité lumineuse d'un éclairage arrière d'affichage à cristaux liquides
WO1995012964A1 (fr) * 1993-11-03 1995-05-11 Science Applications International Corporation Systeme d'illumination uv par l'arriere a haute efficacite pour dispositifs d'affichage electroniques
US5428265A (en) * 1994-02-28 1995-06-27 Honeywell, Inc. Processor controlled fluorescent lamp dimmer for aircraft liquid crystal display instruments

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10013041A1 (de) * 2000-03-17 2001-09-27 Trilux Lenze Gmbh & Co Kg Verfahren und Vorrichtung zum Betrieb einer mit einer Leuchtstofflampe versehenen Leuchte

Also Published As

Publication number Publication date
ATA74396A (de) 2000-07-15
EP0804052A3 (fr) 1999-04-07
AT407461B (de) 2001-03-26

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