EP0326114A1 - Dispositif de commande pour une lampe à décharge - Google Patents

Dispositif de commande pour une lampe à décharge Download PDF

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Publication number
EP0326114A1
EP0326114A1 EP89101287A EP89101287A EP0326114A1 EP 0326114 A1 EP0326114 A1 EP 0326114A1 EP 89101287 A EP89101287 A EP 89101287A EP 89101287 A EP89101287 A EP 89101287A EP 0326114 A1 EP0326114 A1 EP 0326114A1
Authority
EP
European Patent Office
Prior art keywords
drive device
discharge lamp
terized
charac
voltage
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Withdrawn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
EP89101287A
Other languages
German (de)
English (en)
Inventor
Satoshi Suzuki
Fujinori Kimura
Hiroshi Kubota
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.)
Toshiba TEC Corp
Original Assignee
Tokyo Electric Co Ltd
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 Tokyo Electric Co Ltd filed Critical Tokyo Electric Co Ltd
Publication of EP0326114A1 publication Critical patent/EP0326114A1/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Withdrawn legal-status Critical Current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
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2851—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • 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
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/295—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
    • H05B41/298—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2981—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions

Definitions

  • the present invention relates to a drive device for a discharge lamp, and more particularly to a drive device for a discharge lamp such as a fluorescent lamp.
  • a lamp drive device as shown in Fig. 1 has been used for driving a fluorescent lamp.
  • an AC voltage from commercial power source 1 is converted into a DC voltage by rectifier circuit 2.
  • the DC voltage is then applied to series inverter circuit 4 through a couple of power lines VDD and VSS.
  • Series inverter circuit 4 is arranged in a half-bridge connec­tion.
  • Inverter circuit 4 is made up of a couple of transistors 5 and 6 and another couple of capacitors 7 and 8. These transistors 5 and 6 are connected in series between paired power lines VDD and VSS, and capa­citors 7 and 8 are likewise connected between power lines VDD and VSS.
  • Fluorescent lamp 12 is set between lamp sockets LS.
  • Capacitor 13 is connected to the first ends of filaments 12A and 12B.
  • the second end of fila­ment 12A is connected by inductor coil 11 to the node of transistors 5 and 6.
  • the second end of filament 12B is connected to the node of capacitors 7 and 8.
  • capacitor 13 and inductor coil 11 form a resonance circuit which ignites fluorescent lamp 12.
  • a resonance current flows through a series path of inductor coil 11, filament 12A, capacitor 13, and filament 12B, to warm up or preheat filaments 12A and 12B.
  • a voltage across capacitor 13 rises and exceeds a discharge start voltage at which a discharge begins between filaments 12A and 12B.
  • the fluorescent lamp 12 starts to emit light.
  • the above lamp drive device is defective in that replacement of a lamp during operation of the inverter circuit is dangerous.
  • the warm-up mode is set up. In this mode, a poten­tial difference between the surface of fluorescent lamp 12 and ground becomes excessively high, increasing with potential VA at end P of filament 12A.
  • a user contacts the fluorescent lamp 12, he is placed in the path between the lamp sur­face and ground through which a leak current would flow, and may receive an electric shock.
  • an object of the present invention is to provide a drive device for a discharge lamp which eliminates the risk of electric shock to someone being very close to the lamp or replacing the lamp during operation of this device.
  • a drive device for a discharge lamp comprising: a power source circuit with first and second output terminals for producing an AC voltage between the first and second output terminals; a capacitor connected between the first ends of first and second filaments of the discharge lamp; and first and second inductors respectively connected between the first output terminal of the power source circuit and the second end of the first filament, and between the second output terminal of the power source circuit and the second end of the second filament, the first and second inductors cooperating with the capaci­tor to form a resonance circuit which ignites the discharge lamp, and serving as elements to restrict a discharge current flowing between the first and second filaments after a discharge begins in the ignited discharge lamp.
  • an inductance required for the resonance circuit and the current restricting elements is set as the sum of an inductances of the first inductor connected to the first filament and an inductance of the second inductor con­nected to the second filament.
  • the voltage between the first and second output terminals of the power source circuit is divided in accordance with an inductance ratio of the first and second inductors. The voltage division suppresses the partial increase of a potential on the lamp surface, uniforms the lamp sur­face potential distribution, and sets its value at a lower voltage than that obtained when the inductor is coupled with one of the filaments.
  • Fig. 2 shows the drive device for a fluorescent lamp.
  • the drive device is made up of DC power source circuit 22, trigger circuit 20, series inverter circuit 24, and ignition circuit 10.
  • the DC voltage is applied through paired power lines VDD and VSS to trigger circuit 20 and series inverter cir­cuit 24 serving as a high frequency oscillator for 25 KHz.
  • Ignition circuit 10 is connected between the node of transistors 25 and 26 and the node of capacitors 27 and 28.
  • Induction coil L3 is wound in such a direction as to place transistor 25 in a conductive state.
  • Induction coil L2 is wound in such a direction as to place tran­sistor 26 in the conductive state.
  • Exciting coil L1 is coupled in series with ignition circuit 10. The volta­ges across induction coils L2 and L3 as induced when a current flows through exciting coil L1, are opposite in polarity to each other. Those induced voltages are applied across the base-emitter paths of the transistors 25 and 26, respectively.
  • a lamp current flowing through lamp 32 also flows through exciting coil L1.
  • the current of exciting coil L1 gradually decreases due to a magnetic saturation of transformer T1, and eventually the transformer is magnetized in the reverse direction.
  • the voltage induced in induction coils L2 and L3 are also reversed in polarity.
  • the induced voltage becomes large as the lamp current decreases.
  • transistor 26 is instantaneously turned off by the voltage developed in induction coil L3, and transistor 25 is turned on by the voltage deve­loped in induction coil L2.
  • a lamp current flows through a series pass formed of transistor 25, exciting coil L1, inductor 37A, fluorescent lamp 32, and inductor 37B in the direction DR′, so that lamp 32 is lit on.
  • the oscillation transformer T1 is saturated so that the discharge current gradually decreases and the polarity of the magnetization of transformer T1 is again reversed.
  • the voltage is induced in induction coils L2 and L3, and renders tran­sistor 25 nonconductive and transistor 26 conductive.
  • a lamp current flows through a series path formed of inductor 37B, fluorescent lamp 32, inductor 37A, exciting coil L1, and transistor 26 in the direction DR2, so that the lighting of lamp 32 is main­tained.
  • the alternately reversed magneti­zation of oscillation transformer T1 alternately turns on and off the transistors 25 and 26 in a repeated manner, thereby maintaining the lighting of fluorescent lamp 32.
  • diode D8 and resistor R5 are pro­vided for discharging the charge of capacitor C5 through transistor 26 transistors Q1 and Q2, diodes D6 and D7, resistors R10 and R11, and resistors R8 and R9 are pro­vided for stabilizing the voltage applied to lamp 32 when inductors 37A and 37B an d capacitor 33 resonate in the warm-up stage.
  • a resonance by inductors 37A and 37B and the capacitor 33 causes an excessive current to flow the resistors R8 and R9 respectively coupled with transistors 25 and 26. The voltages across the resistors become high enough to render the transistors conductive.
  • those transistors 25 and 26 are turned on. The result is to quicken the magnetic saturation of oscillation transformer T1. In a transient state that the tran­sistors 25 and 26 are being turned off, it quickens the change of their conduction state, to restrict the reso­nance current.
  • a leak current between the surface of fluorescent lamp 32 and ground was measured by using a connection as shown in Fig. 3. That is, a tube of lamp 32 is wrapped with an aluminum foil 34, resistor 35 is inserted bet­ween the foil 34 and ground, and oscilloscope 36 is con­nected between a movable terminal of resistor 35 and ground.
  • the AC power source was a 3-phase power source of 200 V.
  • the measurement was repeated for three different locations (1) to (3) of the foil wrapping on the lamp tube surface.
  • a voltage developed across resistor 35 was measured by the oscilloscope 35 when lamp 32 is in a preheat or warm-up condition, while varying a ratio of the inductances "x" and "y” of inductors 37A and 37B.
  • the obtained voltages were converted into corresponding peak values of a shock current.
  • variations of the peak values of the shock current were plotted against the foil wrapping locations (1) to (3), with parameters of inductance ratios of the inductors.
  • the peak current variations of the conventional lamp drive device could be represented by curve A or B. These curves show that a maximum peak value of the shock current of 150 mA is observed at the tube surface loca­tion 1 or 3 wrapped with the aluminum foil that is closer to the filament connecting to an inductor.
  • the figure of 150 mA is very high as a shock current.
  • a maximum shock current is found at the location 1, and its value is 100 mA at most.
  • the peak values are further reduced.
  • a maximum peak value at the location 1 is only 40 mA.
  • a couple of resonance inductors 37A and 37B, which are not magnetically coupled with each other, are used in the above-mentioned embodiment.
  • each pair of inductors 37A and 37B magnetically are coupled with each other as shown in Fig. 5.
  • capacitors 27 and 28 are used in the first embodiments.
  • capacitors 27 and 28 are replaced by a pair of NPN tran­sistors 38 and 39 so as to form series inverter circuit 24 of a full bridge type.
  • Fig. 7 shows another measuring circuit for measuring a leak current flowing between ground and electronic stabilizer board on which a drive circuit of each embodiment is formed.
  • a 3-phase AC power source of 200 V is connected to the drive circuit fluorescent lamp 43 is connected to the drive circuit.
  • Resistor 44 of 1 kilo ohms is inserted between the stabilizer board 42 and ground, and ammeter 45 for measuring a leak current is connected across the resistor 44.
  • a leak current was measured by using the above measuring circuit, while varying an inductance ratio of the inductors (choke coils) of x : y.
  • the results of the measurements were plotted as shown in Fig. 8.
  • the graph of Fig. 8 clearly shows that a minimum leak current resides in the vicinity of the inductance ratio of 2 : 3.
  • Fig. 9 shows a drive device for a fluorescent lamp according to the fourth embodiment.
  • Switching element SW is connected between first ends of filaments 32A and 32B of fluorescent lamp 32, second ends of filaments 32A and 32B are respectively connected through inductances 37A and 37B to power terminals between which an AC power source voltage is applied from commercial AC power source (12). In this case, it is also possible to reduce the electric shock.

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  • Circuit Arrangements For Discharge Lamps (AREA)
EP89101287A 1988-01-26 1989-01-25 Dispositif de commande pour une lampe à décharge Withdrawn EP0326114A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1553688A JPH01189897A (ja) 1988-01-26 1988-01-26 放電灯点灯装置
JP15536/88 1988-01-26

Publications (1)

Publication Number Publication Date
EP0326114A1 true EP0326114A1 (fr) 1989-08-02

Family

ID=11891528

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89101287A Withdrawn EP0326114A1 (fr) 1988-01-26 1989-01-25 Dispositif de commande pour une lampe à décharge

Country Status (2)

Country Link
EP (1) EP0326114A1 (fr)
JP (1) JPH01189897A (fr)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0659037A2 (fr) * 1993-12-15 1995-06-21 General Electric Company Ballast avec indicateur de son fonctionnement pour lampe à décharge
EP0855850A1 (fr) * 1997-01-27 1998-07-29 MAGNETEK S.p.A. Alimentation pour lampes à décharge avec un circuit résonant équilibré
WO2001008454A1 (fr) * 1999-07-26 2001-02-01 Microlights Limited Lampes electriques perfectionnees
EP1176854A2 (fr) 2000-07-28 2002-01-30 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Réduction de la tension aux bornes des connections de ballasts pour lampes à décharge
EP1671521A2 (fr) * 2003-10-06 2006-06-21 Microsemi Corporation Circuit de partage de courant et dispositif pour faire fonctionner de nombreuses lampes ccf
WO2006074629A1 (fr) * 2005-01-11 2006-07-20 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ballast electronique
US7646152B2 (en) 2004-04-01 2010-01-12 Microsemi Corporation Full-bridge and half-bridge compatible driver timing schedule for direct drive backlight system
US7755595B2 (en) 2004-06-07 2010-07-13 Microsemi Corporation Dual-slope brightness control for transflective displays
US7952298B2 (en) 2003-09-09 2011-05-31 Microsemi Corporation Split phase inverters for CCFL backlight system
US7977888B2 (en) 2003-10-06 2011-07-12 Microsemi Corporation Direct coupled balancer drive for floating lamp structure
US8093839B2 (en) 2008-11-20 2012-01-10 Microsemi Corporation Method and apparatus for driving CCFL at low burst duty cycle rates
US8223117B2 (en) 2004-02-09 2012-07-17 Microsemi Corporation Method and apparatus to control display brightness with ambient light correction
US8358082B2 (en) 2006-07-06 2013-01-22 Microsemi Corporation Striking and open lamp regulation for CCFL controller
US8598795B2 (en) 2011-05-03 2013-12-03 Microsemi Corporation High efficiency LED driving method
US8754581B2 (en) 2011-05-03 2014-06-17 Microsemi Corporation High efficiency LED driving method for odd number of LED strings
US9030119B2 (en) 2010-07-19 2015-05-12 Microsemi Corporation LED string driver arrangement with non-dissipative current balancer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4563719A (en) * 1982-08-30 1986-01-07 Nilssen Ole K Ballasts with built-in ground-fault protection
US4675576A (en) * 1985-04-05 1987-06-23 Nilssen Ole K High-reliability high-efficiency electronic ballast
FR2611326A1 (fr) * 1987-02-24 1988-08-26 Courier De Mere Henri Ballast electronique

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61133597A (ja) * 1984-12-03 1986-06-20 松下電工株式会社 放電灯点灯装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4563719A (en) * 1982-08-30 1986-01-07 Nilssen Ole K Ballasts with built-in ground-fault protection
US4675576A (en) * 1985-04-05 1987-06-23 Nilssen Ole K High-reliability high-efficiency electronic ballast
FR2611326A1 (fr) * 1987-02-24 1988-08-26 Courier De Mere Henri Ballast electronique

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0659037A3 (fr) * 1993-12-15 1997-03-26 Gen Electric Ballast avec indicateur de son fonctionnement pour lampe à décharge.
EP0659037A2 (fr) * 1993-12-15 1995-06-21 General Electric Company Ballast avec indicateur de son fonctionnement pour lampe à décharge
EP0855850A1 (fr) * 1997-01-27 1998-07-29 MAGNETEK S.p.A. Alimentation pour lampes à décharge avec un circuit résonant équilibré
US6118223A (en) * 1997-01-27 2000-09-12 Magnetek, Inc. Power supply for discharge lamps with balanced resonant circuit
WO2001008454A1 (fr) * 1999-07-26 2001-02-01 Microlights Limited Lampes electriques perfectionnees
EP1176854A2 (fr) 2000-07-28 2002-01-30 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Réduction de la tension aux bornes des connections de ballasts pour lampes à décharge
EP1176854A3 (fr) * 2000-07-28 2004-12-15 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Réduction de la tension aux bornes des connections de ballasts pour lampes à décharge
US7952298B2 (en) 2003-09-09 2011-05-31 Microsemi Corporation Split phase inverters for CCFL backlight system
EP1671521A2 (fr) * 2003-10-06 2006-06-21 Microsemi Corporation Circuit de partage de courant et dispositif pour faire fonctionner de nombreuses lampes ccf
US7977888B2 (en) 2003-10-06 2011-07-12 Microsemi Corporation Direct coupled balancer drive for floating lamp structure
US8222836B2 (en) 2003-10-06 2012-07-17 Microsemi Corporation Balancing transformers for multi-lamp operation
US8008867B2 (en) 2003-10-06 2011-08-30 Microsemi Corporation Arrangement suitable for driving floating CCFL based backlight
US7990072B2 (en) 2003-10-06 2011-08-02 Microsemi Corporation Balancing arrangement with reduced amount of balancing transformers
US7932683B2 (en) 2003-10-06 2011-04-26 Microsemi Corporation Balancing transformers for multi-lamp operation
EP1671521A4 (fr) * 2003-10-06 2007-06-13 Microsemi Corp Circuit de partage de courant et dispositif pour faire fonctionner de nombreuses lampes ccf
US8223117B2 (en) 2004-02-09 2012-07-17 Microsemi Corporation Method and apparatus to control display brightness with ambient light correction
US7965046B2 (en) 2004-04-01 2011-06-21 Microsemi Corporation Full-bridge and half-bridge compatible driver timing schedule for direct drive backlight system
US7646152B2 (en) 2004-04-01 2010-01-12 Microsemi Corporation Full-bridge and half-bridge compatible driver timing schedule for direct drive backlight system
US7755595B2 (en) 2004-06-07 2010-07-13 Microsemi Corporation Dual-slope brightness control for transflective displays
US7675242B2 (en) 2005-01-11 2010-03-09 Osram Gesellschaft Mit Beschraenkter Haftung Electronic ballast
WO2006074629A1 (fr) * 2005-01-11 2006-07-20 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ballast electronique
CN101099416B (zh) * 2005-01-11 2011-06-22 电灯专利信托有限公司 电子镇流器(evg)
US8358082B2 (en) 2006-07-06 2013-01-22 Microsemi Corporation Striking and open lamp regulation for CCFL controller
US8093839B2 (en) 2008-11-20 2012-01-10 Microsemi Corporation Method and apparatus for driving CCFL at low burst duty cycle rates
US9030119B2 (en) 2010-07-19 2015-05-12 Microsemi Corporation LED string driver arrangement with non-dissipative current balancer
US8598795B2 (en) 2011-05-03 2013-12-03 Microsemi Corporation High efficiency LED driving method
US8754581B2 (en) 2011-05-03 2014-06-17 Microsemi Corporation High efficiency LED driving method for odd number of LED strings
USRE46502E1 (en) 2011-05-03 2017-08-01 Microsemi Corporation High efficiency LED driving method

Also Published As

Publication number Publication date
JPH01189897A (ja) 1989-07-31

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