EP0978221B1 - Circuiterie pour fonctionnement modulable d'un tube fluorescent - Google Patents

Circuiterie pour fonctionnement modulable d'un tube fluorescent Download PDF

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Publication number
EP0978221B1
EP0978221B1 EP98924143A EP98924143A EP0978221B1 EP 0978221 B1 EP0978221 B1 EP 0978221B1 EP 98924143 A EP98924143 A EP 98924143A EP 98924143 A EP98924143 A EP 98924143A EP 0978221 B1 EP0978221 B1 EP 0978221B1
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EP
European Patent Office
Prior art keywords
arrangement according
circuit arrangement
frequency
switches
circuit
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
Application number
EP98924143A
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German (de)
English (en)
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EP0978221A1 (fr
Inventor
Berthold Birk
Günter Hahlganss
Walter Kares
Ulrich Roskoni
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Siemens AG
Original Assignee
Siemens AG
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
Priority claimed from DE1997117309 external-priority patent/DE19717309A1/de
Priority claimed from DE19733939A external-priority patent/DE19733939A1/de
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0978221A1 publication Critical patent/EP0978221A1/fr
Application granted granted Critical
Publication of EP0978221B1 publication Critical patent/EP0978221B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H05B41/2821—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 by means of a single-switch converter or a parallel push-pull converter in the final stage
    • H05B41/2822—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 by means of a single-switch converter or a parallel push-pull converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/04—Dimming circuit for fluorescent lamps

Definitions

  • the invention relates to a circuit arrangement for dimmable Operation of a fluorescent lamp, in particular for use in Motor vehicles as instrument lighting. From a standing start Corresponding circuit arrangements are known in the art, where the fluorescent lamp is operated at an operating frequency becomes. By switching the operating frequency on and off with one device and thus the lamp with one Dimming frequency, which is above the human's visual frequency Eye lies, that is achieved for the human eye The impression arises that the fluorescent lamp is of different brightness, depending on the pulse width of the dimming frequency.
  • Such a circuit arrangement is known from JP-A-06333695. To the lamp current by the fluorescent lamp, it is necessary to either to provide an additional controller or to use an elaborately stabilized resonant circuit.
  • the object of the invention is therefore to provide a simple structure Specify circuitry for dimming a fluorescent lamp.
  • a particularly simple push-pull converter is replaced by one Resonant circuit consisting of a capacitance and an inductor, which is connected to a first pole of the supply voltage.
  • the oscillating circuit is alternately direct or via two switches via a third switch with the second pole of the supply voltage connectable.
  • the two switches are each with one connection the connections of the capacitance and / or the inductance are connected.
  • fluorescent lamps can either be parallel to the inductance and / or capacitance can be arranged or via a transformer are supplied with the operating frequency, the primary winding of the Transformer advantageously forms the inductance of the resonant circuit.
  • circuit arrangement according to claim 5 is a circuit arrangement realized with few components.
  • the circuit arrangement according to claim 6 gives a particularly effective Regulation of the lamp current, which is nevertheless simple and with few Components is built.
  • the positive feedback device in the form of a coil on the same bobbin how the inductance is applied can be done easily and simultaneously with the inductor.
  • the lamp current setpoint depends on the temperature the fluorescent lamp or the environment is specified, a Minimum brightness reached even at low temperatures.
  • Circuit arrangements according to the invention of particularly simple construction are given in claims 9 and 12.
  • a microprocessor for the control device the possibly even for other tasks, for example in an instrument cluster a motor vehicle is present and the invention Brightness control used for instrument lighting the circuit can be implemented with little component effort.
  • the circuit with a separate microprocessor or be realized by means of switching gates.
  • the switch before or at the beginning of the pulse sequence pause can be in the resonant circuit contained current short-circuited and so an afterglow of the Fluorescent lamp can be prevented safely.
  • a Ballast choke between a pole of the supply voltage and the The circuit can additionally stabilize the oscillating circuit and are kept sinusoidal.
  • the push-pull converter from FIG. 1 has an oscillating circuit consisting of the capacitor C and the coil L, which is connected directly to the positive supply voltage and can be connected via the transistors S1, S2 alternately to the ground potential via the series reactor Lv and the transistor S3.
  • the following description assumes that the transistor S3 is turned on, that is to say that the transistors S1, S2 are connected to the second pole of the supply voltage.
  • the voltage is also coupled through the coil L1, which is wound on the same coil former as the coil L, and the alternating voltage that occurs alternately blocks the transistors S1, S2 with the oscillation frequency of the resonant circuit.
  • the operating point of the two transistors S1, S2 is set via the resistor R.
  • the resonant circuit transmits its energy via the transformer, which is formed from the coils L, L1 and L2, to the lamp circuit which, in addition to the coil L2, also has the fluorescent lamp KL, the impedance Z and a shunt SH.
  • the voltage is tapped between the fluorescent lamp KL and the shunt SH and fed to the rectifier G.
  • the rectified voltage U1 is present at the minus input of the comparator K.
  • the square wave voltage U3 of the frequency f3 at the output of the comparator K1 is changed in its pulse width W3.
  • the current setpoint can be set by the level of the triangular voltage can be set in Figure 2b.
  • the output voltage U3 of the comparator K1 is connected to an input of the AND gate A led while to the second input of the AND gate A the dimming frequency f2 is set with the voltage curve U4 ( Figure 2a).
  • the dimming frequency f2 is rectangular and its pulse width W2 also changeable.
  • the pulse width W2 of the dimming frequency f2 is determined the duty cycle of the push-pull converter and thus the fluorescent lamp KL, as will be described in more detail later.
  • the Pulse width W2 of the dimming frequency f2 is e.g. either automatically depending the ambient brightness or manually depending on the desired Brightness of the fluorescent lamp KL adjustable.
  • the voltage U5 is present at the output of the AND gate A: It points during the pulse width W2 of the dimming frequency f2 switching pulses of the pulse width W3 with the switching frequency f3.
  • the transistor S3 is turned on the switching pulses are controlled with the pulse width W3.
  • the transistor S3 With the first pulse with the pulse width W3 during a pulse width W2 Dimming frequency f2, the transistor S3 is turned on.
  • the current IB can flow from the supply voltage source + UB into the time Resonant circuit flow.
  • the resonant circuit begins at its resonance frequency to swing.
  • the resonant circuit oscillates further and the current stored in the resonant circuit flows through the series choke Lv and the diode D connected as a freewheeling diode in the Resonant circuit back, but decreases accordingly.
  • transistor S3 switches through again: current can flow out of the Supply voltage source + UB flow into the resonance circuit and the Current IB increases during the duty cycle.
  • the current fluctuates during the pulse width W2 of the dimming frequency f2 around its mean IM ( Figure 2 f). With increasing or decreasing Pulse width W3 is increased or current IB reduced and the lamp current IL via the transformer. If the pulse width W2 of the dimming frequency f2 has ended and the last pulse the pulse sequence of frequency f3 at transistor t4 at time t4 has transistor S3 during the pause time P of the frequency f2 locked. The resonant circuit vibrates due to its load by the lamp KL and own losses, which become currents IB and IL back to 0 and the fluorescent lamp goes out. With the beginning of the next Pulse of the dimming frequency f2, it begins to light up again previously described. Since the dimming frequency f2 is above human The fluorescent lamp appears to the human eye depending on the pulse width W2 differently bright.
  • the fluorescent lamp KL can with a sufficiently large supply voltage also in the primary circuit e.g. arranged parallel to the capacitor C. are so that the secondary coil L2 can be dispensed with. Furthermore, the voltage can also be set via a shunt in the primary circuit can be tapped for the rectifier G.
  • the circuit from FIG. 3 also has an oscillating circuit from the capacitor C and the coil L on that with the positive supply voltage is connected and alternately via transistors S4, S5 is connectable to ground potential.
  • the control device SE is via a control line SL1, SL2 with the base of the transistors S4, S5 connected.
  • the dimming frequency f2 (FIG. 4a) with the pulse sequences controlled with the switching frequency f3 alternately, the duration T5 of the individual contiguous pulses for a transistor S4, S5 half of the oscillation period T1 of the resonant circuit is ( Figure 4b, c).
  • the resonant circuit oscillates almost sinusoidally, so that only small disturbing harmonics occur. Therefore it is also advantageous if the oscillation period T of the resonance frequency is an even multiple the oscillation period T3 is the switching frequency f3.
  • the oscillation period T1 of the resonant circuit corresponds to four times the oscillation period T3 of the individual pulses.
  • the pulse width W3 of the individual pulses becomes the average current IM in the primary circuit and thus also the lamp current IL in the secondary circuit.
  • the dimming frequency f2 is only present internally in the control device SE.
  • Your pulse width W2 determines the duty cycle of the resonant circuit and so that the duty cycle of the fluorescent lamp KL.
  • the one shown in Figure 3 Circuit corresponds to a control. Individuals can do this Pulse width values W2 of the dimming frequency f2 for various desired ones Brightnesses and / or operating temperatures in the storage devices be stored, which are directly present in the memory device SE or which the control device SE can access.
  • FIG. 5 shows a fluorescent lamp L, which is connected to a high-voltage capacitor Z with the secondary circuit L2 of a transformer.
  • the transformer is energized in its primary circuit L by two push-pull switching MOSFET transistors S6 and S7, which are controlled by a control device SL, the primary circuit L of the transformer being connected to the operating voltage U B at the same time.
  • Each gate G of the transistors S6, S7 is connected to the control device SL.
  • the drain D of each transistor S6, S7 leads to the primary winding L of the transformer, the sources S of the MOSFET transistors S6, S7 leading together to a shunt resistor R1 which is connected to ground.
  • the control device SL processes a voltage drop across the shunt resistor R1 as an input signal.
  • the voltage drop is fed to the inverting input of a comparator K, at the non-inverting input of which there is a reference voltage U REF with a constant value.
  • the output of the comparator K is connected to the control device SL.
  • the two MOSFET transistors S6, S7 are successively each triggered once with a pulse 1.
  • This is the resonant circuit, consisting of the secondary coil L2, the high-voltage capacitor Z and the fluorescent lamp KL triggered.
  • the resonant circuit reverberates an e-function (see signal 4, point 2).
  • the gas in the cold cathode fluorescent lamp KL can ionize and organize itself during this time.
  • the transistors S6, S7 continuously controlled alternately (signal 1 and 2, point 4).
  • the Cold cathode fluorescent lamp KL emits light immediately from this point in time (as signal 4 can be seen in point 3).
  • the control device SL controls the MOSFET transistors S6, S7 in a pulsed manner on ( Figure 6a, signal 1 and 2).
  • the one through the MOSFET transistors S6, S7 current flowing is considered voltage drop across the Shunt resistance R1 measured and evaluated by comparator K2, which depends on whether the measured voltage is the reference value exceeds or not, emits a low or high signal.
  • the output signal of the comparator K2 becomes logical in the control device SL linked with signal 1. This causes the MOSFET transistors S6, S7 during control by the control logic in the Clock of the output signal of the comparator K controlled or blocked become.
  • This device has the advantage that the flicker-free operation of the fluorescent lamp L only through the special control of the MOSFET transistors S6, S7 is reached. On extensive control circuits, as usual, you can do without.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)

Claims (19)

  1. Circuit permettant de faire varier la luminosité d'un tube fluorescent, avec une fréquence de service (f1) déterminée, avec un dispositif permettant de connecter et de déconnecter la fréquence de service (f1) avec une fréquence de variation de la luminosité (f2), la largeur (W2) des impulsions de la fréquence de variation de la luminosité (f2) pouvant être modifiée et la fréquence de variation de la luminosité (f2) étant inférieure à la fréquence de service (f1) caractérisé par le fait que le courant du tube fluorescent, pendant la durée de la largeur (W2) des impulsions de la fréquence de variation de la luminosité (f2), peut être réglé en connectant et en déconnectant la tension d'alimentation avec une fréquence de commutation (f3) ayant une largeur d'impulsions (W3) modifiable, la fréquence de commutation (f3) étant supérieure à la fréquence de service (f1).
  2. Circuit selon la revendication 1 caractérisé par le fait que le circuit comporte un convertisseur symétrique destiné à produire la fréquence de service (f1).
  3. Circuit selon la revendication 2 caractérisé par le fait que le convertisseur symétrique comporte un circuit résonant avec une capacité et une inductance (L),
    que le circuit résonant est relié à une première borne de la tension d'alimentation,
    que le circuit résonant peut être relié, à tour de rôle par l'intermédiaire d'un premier et d'un deuxième commutateur (S1, S2, S4, S5), qui sont reliés chacun à une borne de l'inductance (L) et/ou de la capacité (C), à la deuxième borne de la tension d'alimentation directement ou bien par l'intermédiaire d'un troisième commutateur (S3),
    que le premier et le deuxième commutateur (S1, S2, S4, S5) sont raccordés chacun par une borne de puissance à une borne de l'inductance (L) et/ou de la capacité (C),
    que le tube fluorescent (KL) est monté en parallèle sur l'inductance (L) et/ou la capacité (C) ou qu'il peut être alimenté avec la fréquence de service (f1) par l'intermédiaire d'un transformateur, un enroulement primaire du transformateur constituant d'une façon avantageuse l'inductance (L) du circuit résonant.
  4. Circuit selon la revendication 3 caractérisé par le fait que les commutateurs (S1, S2, S3, S4, S5) sont des commutateurs électroniques.
  5. Circuit selon la revendication 3 ou 4 caractérisé par le fait que le premier et le deuxième commutateur (S1, S2) peuvent être reliés, par leur borne de puissance respective, par l'intermédiaire du troisième commutateur (S3), à la deuxième borne de la tension d'alimentation,
    que le troisième commutateur (S3) est relié, par l'intermédiaire d'une soupape de courant (D), à la première borne de la tension d'alimentation,
    que la soupape de courant (D) sert de diode à roue libre lorsque le troisième commutateur n'est pas passant,
    que les bornes de commande du premier et du deuxième commutateur (S1, S2) sont reliées à un dispositif de contre-réaction positive,
    que le troisième commutateur peut être actionné par des séquences d'impulsions, dans lesquelles les différentes impulsions ont une période de commutation (T3 = 1 : f3) et sont libérées pendant la durée de la largeur (W2) des impulsions de la fréquence de variation de la luminosité (f2).
  6. Circuit selon la revendication 5 caractérisé par le fait que, sur la borne de commande du troisième commutateur, est raccordée la sortie d'un circuit porte additif ET (U), sur l'une des entrées duquel est appliquée la fréquence de variation de la luminosité (f2) et sur l'autre entrée, la sortie d'un comparateur (K), sur l'entrée positive duquel est appliqué un signal en dents de scie ou triangulaire ayant la fréquence de commutation (f3) et sur l'entrée négative duquel est appliqué un signal qui correspond au courant (IL) effectif ou supposé du tube fluorescent ou au courant primaire (IB).
  7. Circuit selon la revendication 5 ou 6 caractérisé par le fait que le dispositif de contre-réaction positive se compose d'une bobine (L1), qui est bobinée sur le même support que l'inductance (L) et que ses bornes respectives sont raccordées aux bornes de commande du premier et, respectivement, du deuxième commutateur (S1, S2).
  8. Circuit selon l'une des revendications précédentes caractérisé par le fait que la valeur de consigne du courant du tube (IL) est donnée en fonction de la température du tube fluorescent ou de la température ambiante.
  9. Circuit selon l'une des revendications 1 à 3 caractérisé par l e fait que le premier et le deuxième commutateur (S4, S5) sont reliés chacun par une borne de puissance à la deuxième borne de la tension d'alimentation, que le premier et le deuxième commutateur (S4, S5) sont reliés chacun par leur borne de commande respective à un dispositif de commande (SE), que le dispositif de commande (SE) excite les commutateurs (S4, S5) l'un après l'autre avec des séquences d'impulsions, dont les différentes impulsions ont la durée de la période de commutation (T3), la durée (T5) des différentes impulsions pour un commutateur (S4, S5), qui sont enchaínées les unes aux autres, étant égale à la moitié de la durée d'oscillation (T1) du circuit résonant.
  10. Circuit selon la revendication 9 caractérisé par le fait que la fréquence de commutation (f3) est un multiple à nombre pair de la fréquence de service (f1).
  11. Circuit selon la revendication 9 ou 10 caractérisé par le fait que la fréquence de service (f1) correspond approximativement à la fréquence de résonance du circuit résonant.
  12. Circuit selon la revendication 1 ou 2 caractérisé par le fait que deux commutateurs de puissance (S6, S7) sont disposés dans le circuit primaire d'un transformateur et qu'ils peuvent être commandés en push-pull par un dispositif de commande (SL), qu'une résistance de shunt (R1) est disposée entre les commutateurs (S6, S7) et la masse, la chute de tension à ses bornes étant utilisée pour la régulation du courant.
  13. Circuit selon la revendication 12 caractérisé par le fait que la chute de tension est appliquée, par l'intermédiaire d'un comparateur (K2), au dispositif de commande (SL), la chute de tension étant appliquée à une première entrée du comparateur (K2), alors qu'une tension de référence est appliquée sur sa deuxième entrée.
  14. Circuit selon la revendication 12 ou 13 caractérisé par le fait que les commutateurs (S6, S7) sont des transistors à effet de champ à grille isolée par une couche d'oxyde de silicium (ou transistors MOSFET), dont le drain (D) est relié au circuit primaire (L) du transformateur et dont la grille (G) est reliée à la logique de commande (SL), les sources (S) des deux transistors (S6, S7) étant reliées aussi bien à la résistance de shunt (K2) qu'au comparateur (K2).
  15. Circuit selon l'une des revendications 9 à 14 caractérisé par le fait que le dispositif de commande (SE, SL) ferme et, ensuite, rouvre simultanément les deux commutateurs (S4, S5, S6, S7) avant ou au début de la pause de séquence d'impulsions.
  16. Circuit selon l'une des revendications 9 à 11 ou 15 caractérisé par le fait que le dispositif de commande (SE) règle la largeur (W3) des impulsions de la fréquence de commutation (f3) en fonction du courant du tube fluorescent.
  17. Circuit selon l'une des revendications 9 à 11 ou 15 à 16 caractérisé par le fait que le dispositif de commande (SE) commande la largeur (W3) des impulsions de la fréquence de commutation (f3) sur la base de la température du tube fluorescent ou de la température ambiante.
  18. Circuit selon l'une des revendications 9 à 11 ou 15 à 17 caractérisé par le fait que le dispositif de commande (SE) commande la largeur (W2) des impulsions de la fréquence de variation de la luminosité (f2) en fonction de la luminosité ambiante ou d'un codeur de valeur de consigne.
  19. Circuit selon l'une des revendications 9 à 11 ou 15 à 18 caractérisé par le fait qu'une bobine d'appoint (Lv) est disposée entre une borne de la tension d'alimentation et le circuit résonant.
EP98924143A 1997-04-24 1998-04-17 Circuiterie pour fonctionnement modulable d'un tube fluorescent Expired - Lifetime EP0978221B1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE19717309 1997-04-24
DE1997117309 DE19717309A1 (de) 1997-04-24 1997-04-24 Gegentaktwandler mit überlagerter Stromregelung
DE19733939A DE19733939A1 (de) 1997-08-06 1997-08-06 Schaltungsanordnung zum dimmbaren Betrieb einer Leuchtstofflampe
DE19733939 1997-08-06
PCT/EP1998/002290 WO1998048597A1 (fr) 1997-04-24 1998-04-17 Circuiterie pour fonctionnement modulable d'un tube fluorescent

Publications (2)

Publication Number Publication Date
EP0978221A1 EP0978221A1 (fr) 2000-02-09
EP0978221B1 true EP0978221B1 (fr) 2004-12-22

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EP98924143A Expired - Lifetime EP0978221B1 (fr) 1997-04-24 1998-04-17 Circuiterie pour fonctionnement modulable d'un tube fluorescent

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Country Link
US (1) US6351080B1 (fr)
EP (1) EP0978221B1 (fr)
JP (1) JP4116092B2 (fr)
DE (1) DE59812414D1 (fr)
WO (1) WO1998048597A1 (fr)

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JPH09245976A (ja) 1996-03-01 1997-09-19 Mitsubishi Electric Corp 放電灯調光点灯装置
US5920155A (en) * 1996-10-28 1999-07-06 Matsushita Electric Works, Ltd. Electronic ballast for discharge lamps

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WO1998048597A1 (fr) 1998-10-29
JP4116092B2 (ja) 2008-07-09
US6351080B1 (en) 2002-02-26
JP2002511181A (ja) 2002-04-09
DE59812414D1 (de) 2005-01-27
EP0978221A1 (fr) 2000-02-09

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