EP0082031A1 - Circuit for controlling the light intensity of a fluorescent lamp fed by a direct current - Google Patents

Circuit for controlling the light intensity of a fluorescent lamp fed by a direct current Download PDF

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Publication number
EP0082031A1
EP0082031A1 EP82402038A EP82402038A EP0082031A1 EP 0082031 A1 EP0082031 A1 EP 0082031A1 EP 82402038 A EP82402038 A EP 82402038A EP 82402038 A EP82402038 A EP 82402038A EP 0082031 A1 EP0082031 A1 EP 0082031A1
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EP
European Patent Office
Prior art keywords
converter
voltage
signal
control member
ramp
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Withdrawn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
EP82402038A
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German (de)
French (fr)
Inventor
Raymond Max Brosillon
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.)
Safran Electrical and Power SAS
Precision Mecanique Labinal SA
Original Assignee
Labinal SA
Precision Mecanique Labinal SA
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Filing date
Publication date
Application filed by Labinal SA, Precision Mecanique Labinal SA filed Critical Labinal SA
Publication of EP0082031A1 publication Critical patent/EP0082031A1/en
Withdrawn legal-status Critical Current

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    • 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
    • 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
    • Y10S315/07—Starting and control circuits for gas discharge lamp using transistors

Definitions

  • the present invention relates to a device for controlling the light intensity of a fluorescent tube supplied on a DC voltage, such as for example a fluorescent lighting tube of an aircraft, of an automobile or of a lamp. portable on battery.
  • the present invention therefore proposes to provide a device for controlling the light intensity of a fluorescent tube supplied with a DC voltage, which can adapt to all the needs of the user and to many different configurations of converters.
  • Another object of the invention is to provide such a device which can use simple control means, easy to develop, not very sensitive to parasites and non-disturbing.
  • Yet another objective of the invention is to provide such a device which, while being capable of adapting to many types of converters, retains an acceptable yield even at reduced speed, that is to say for the weak light intensity values.
  • Another objective, still of the invention, is to provide such a device which is simple and economical in construction.
  • the subject of the invention is a device for controlling the light intensity of a fluorescent tube supplied with a direct voltage via a converter, in which the duration of voltage pulses authorizing ignition is varied. of the tube, characterized in that it comprises a control member and means for generating a chopped signal with a chopping rate determined by said control member, said chopped signal being sent to a sensitive element of the converter to temporarily block and repetitively said converter at the rate of said chopped signal.
  • the blocking at variable duty cycle of the converter thus produced is carried out at low frequency, which facilitates adaptation to many types of converters and makes it possible to maintain an acceptable efficiency even at reduced speed.
  • Repetitive blocking of the converter causes a corresponding blocking of the fluorescent tube in a brief and repetitive manner, the variation in light intensity being thus without visual disturbance, without blinking and without stroboscopic effect.
  • control member is a member allowing the establishment of a continuous control voltage, for example a variable potentiometer.
  • This potentiometer can be supplied for example from the DC supply voltage of the network and has at least two positions, namely a position allowing operation at full power of the fluorescent tube and a position allowing only operation at power scaled down.
  • the device then advantageously comprises a ramp generator and a modulator mainly comprising a comparator one of the inputs of which receives the signal from the ramp generator while the said DC control voltage is displayed on its other input so as to generate a chopped signal of constant potential but whose chopping rate varies as a function of the value of the displayed control potential, the chopping rate being zero when this potential is equal to the peak potential of the ramp generator and becoming all the greater that this potential is diminished.
  • the chopped signal leaving the modulator is advantageously sent to a converter blocking circuit.
  • the latter may advantageously include a transistor, the base of which receives the chopped signal and which makes it possible, when thus made conductive, to ground a converter power transistor, for example a transistor of a converter power oscillator. .
  • the device includes a circuit stabilized by the continuous network to allow stable operation of the assembly over a wide range of variation of the network supply voltage.
  • control member can be designed so as not to address a voltage below a certain threshold so as not to block the converter beyond the limit allowing stable operation of the fluorescent tube .
  • the comparator 12 will emit a chopped signal whose chopping rate, that is to say the ratio of the zero potential duration of the signal to the total signal duration, i.e. the ramp period, will be 1/4.
  • This signal sent by the conductor 16 to the transistor 18 therefore blocks the converter at a frequency of 200 Hz for each time 3/4 of the period corresponding to this frequency.
  • the light intensity in the fluorescent tube will be about 1/4 of the maximum intensity.
  • control member intended to address a control potential of Uc can be controlled manually, or on the contrary controlled by any system. It can be constituted, very simply, by a three-position switch making it possible to display for example a zero potential, a potential greater than 100% of the top of the ramp and an intermediate potential, for example at 25%. It can also be constituted by a mechanically controlled potentiometer adjustable to discrete values or, on the contrary, continuously variable. It can also be constituted by an electronic circuit making it possible to address, according to a manual or automatic instruction, a determined potential Uc.
  • the other electronic means shown can also be replaced by equivalent means accessible to those skilled in the art.
  • the interface 17 will be structured as a function of the nature and characteristics of the converter which it must control, mlinterface 17 which can advantageously be constituted by an interchangeable or adjustable module.

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  • Circuit Arrangements For Discharge Lamps (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)

Abstract

Dispositif de commande de l'intensité lumineuse d'un tube fluorescent (4) alimenté sur une tension continue (Vcc) comportant une alimentation stabilisée (5), un générateur de rampe (9), un modulateur (10) recevant le signal de rampe et sensible à un organ de commande lui adressant une tension (Uc), pour générer un signal haché dont le taux de découpage est déterminé par l'organe de commande. Le signal est adressé au convertisseur (2, 3) du tube par l'intermédiaire d'un circuit d'interface (17). Application au réglage de l'intensité de tubes sur aéronef, automobile ou lampe portable.Device for controlling the light intensity of a fluorescent tube (4) supplied on a direct voltage (Vcc) comprising a stabilized supply (5), a ramp generator (9), a modulator (10) receiving the ramp signal and sensitive to a control unit addressing a voltage (Uc) to it, to generate a chopped signal whose chopping rate is determined by the control unit. The signal is sent to the converter (2, 3) of the tube via an interface circuit (17). Application to adjusting the intensity of tubes on aircraft, cars or portable lamps.

Description

La présente invention a trait à un dispositif de commande de l'intensité lumineuse d'un tube fluorescent alimenté sur une tension continue, comme par exemple un tube d'éclairage fluorescent d'un aéronef, d'une automobile ou encore d'une lampe portable sur batterie.The present invention relates to a device for controlling the light intensity of a fluorescent tube supplied on a DC voltage, such as for example a fluorescent lighting tube of an aircraft, of an automobile or of a lamp. portable on battery.

On sait que, pour l'alimentation de tubes fluorescents à partir d'un réseau continu, on utilise des convertisseurs qui sont alimentés par le réseau et qui comprennent en général un oscillateur de puissance débitant dans le primaire d'un transformateur dont le secondaire est relié au tube. Les contraintes imposées par le fonctionnement du tube fluorescent interdisent, dans la pratique, de contrôler l'intensité lumineuse du tube par une modification des conditions d'alimentation. Or, il est hautement désirable de pouvoir contrôler et modifier l'intensité lumineuse d'un tube d'éclairage fluorescent alimenté à partie d'un réseau continu et ceci dans de nombreuses applications.It is known that, for the supply of fluorescent tubes from a continuous network, converters are used which are supplied by the network and which generally include a power oscillator outputting in the primary of a transformer whose secondary is connected to the tube. The constraints imposed by the operation of the fluorescent tube prevent, in practice, controlling the light intensity of the tube by modifying the supply conditions. However, it is highly desirable to be able to control and modify the light intensity of a fluorescent lighting tube supplied from a continuous network and this in many applications.

On a déjà décrit, dans la demande de brevet PCT/81/00184, un procédé de commande d'une lampe à fluorescence alimentée en courant continu dans lequel, pour diminuer l'intensité lumineuse, on diminue la valeur moyenne de la durée de trains d'impulsions en pilotant un interrupteur transistorisé interrompant et autorisant de façon alternée l'alimentation du convertisseur de la lampe. Une telle réalisation est compliquée et n'est pas applicable facilement au cas de la commande de plusieurs ballasts de lampes par la même tension de commande.We have already described, in patent application PCT / 81/00184, a method of controlling a fluorescent lamp supplied with direct current in which, to decrease the light intensity, the average value of the train duration is decreased pulses by driving a solid-state switch interrupting and authorizing alternately the supply of the lamp converter. Such an embodiment is complicated and is not easily applicable in the case of the control of several lamp ballasts by the same control voltage.

On a également décrit, dans le brevet US 4 251 752, une commande à rapport cyclique variable mais s'appliquant directement sur la fréquence de travail du ballast, avec les inconvénients qui en découlent.There has also been described, in US Pat. No. 4,251,752, a control with variable duty cycle but applying directly to the working frequency of the ballast, with the drawbacks which result therefrom.

La présente invention se propose donc de fournir un dispositif de commande de l'intensité lumineuse d'un tube fluorescent alimenté sur une tension continue, qui puisse s'adapter à tous les besoins de l'utilisateur et à de nombreuses configurations différentes de convertisseurs.The present invention therefore proposes to provide a device for controlling the light intensity of a fluorescent tube supplied with a DC voltage, which can adapt to all the needs of the user and to many different configurations of converters.

Un autre objectif de l'invention est de fournir un tel dispositif qui puisse utiliser des moyens de commande simples, faciles à élaborer, peu sensibles aux parasites et non perturbants.Another object of the invention is to provide such a device which can use simple control means, easy to develop, not very sensitive to parasites and non-disturbing.

Un autre objectif encore de l'invention est de fournir un tel dispositif qui, tout en étant susceptible de s'adapter à de nombreux types de convertisseurs, conserve un rendement acceptable même à régime réduit, c'est-à-dire pour les faibles valeurs de l'intensité lumineuse.Yet another objective of the invention is to provide such a device which, while being capable of adapting to many types of converters, retains an acceptable yield even at reduced speed, that is to say for the weak light intensity values.

Un autre objectif, encore de l'invention est de fournir un tel dispositif qui soit de construction simple et économique.Another objective, still of the invention, is to provide such a device which is simple and economical in construction.

L'invention a pour objet un dispositif de commande de l'intensité lumineuse d'un tube fluorescent alimenté sur une tension continue par l'intermédiaire d'un convertisseur, dans lequel on fait varier la durée d'impulsions de tension autorisant l'allumage du tube, caractérisé en ce qu'il comporte un organe de commande et des moyens pour générer un signal haché avec un taux de découpage déterminé par ledit organe de commande, ledit signal haché étant adressé à un élément sensible du convertisseur pour bloquer temporairement et de façon répétitive ledit convertisseur au rythme dudit signal haché.The subject of the invention is a device for controlling the light intensity of a fluorescent tube supplied with a direct voltage via a converter, in which the duration of voltage pulses authorizing ignition is varied. of the tube, characterized in that it comprises a control member and means for generating a chopped signal with a chopping rate determined by said control member, said chopped signal being sent to a sensitive element of the converter to temporarily block and repetitively said converter at the rate of said chopped signal.

De façon avantageuse, le blocage à rapport cyclique variable du convertisseur ainsi réalisé est effectué à basse fréquence, ce qui facilite d'adaptation à de nombreux types de convertisseurs et permet de conserver un rendement acceptable même à régime réduit.Advantageously, the blocking at variable duty cycle of the converter thus produced is carried out at low frequency, which facilitates adaptation to many types of converters and makes it possible to maintain an acceptable efficiency even at reduced speed.

Le blocage répétitif du convertisseur entraîne un blocage correspondant du tube fluorescent de façon brève et répétitive, la variation d'intensité lumineuse se faisant ainsi sans gêne visuelle, sans clignotement et sans effet stroboscopique.Repetitive blocking of the converter causes a corresponding blocking of the fluorescent tube in a brief and repetitive manner, the variation in light intensity being thus without visual disturbance, without blinking and without stroboscopic effect.

Dans une forme de réalisation préférée, l'organe de commande est un organe permettant l'établissement d'une tension de commande continue, par exemple un potentiomètre variable. Ce potentiomètre peut être alimenté par exemple à partir de la tension continue d'alimentation du réseau et présente au moins deux positions, à savoir une position permettant le fonctionnement à pleine puissance du tube fluorescent et une position n'autorisant qu'un fonctionnement à puissance réduite.In a preferred embodiment, the control member is a member allowing the establishment of a continuous control voltage, for example a variable potentiometer. This potentiometer can be supplied for example from the DC supply voltage of the network and has at least two positions, namely a position allowing operation at full power of the fluorescent tube and a position allowing only operation at power scaled down.

Le dispositif comporte alors de façon avantageuse un générateur de rampe et un modulateur comprenant principalement un comparateur dont l'une des entrées reçoit le signal du générateur de rampe alors que l'on affiche sur son autre entrée ladite tension continue de commande de façon à générer un signal haché de potentiel constant mais dont le taux de découpage varie en fonction de la valeur du potentiel de commande affiché, le taux de découpage étant nul lorsque ce potentiel est égal au potentiel de crête du générateur de rampe et devenant d'autant plus grand que ce potentiel est diminué. Le signal haché sortant du modulateur est avantageusement adressé à un circuit de blocage de convertisseur. Ce dernier peut avantageusement comporter un transistor dont la base reçoit le signal haché et qui permet, lorsqu'il est ainsi rendu conducteur, de mettre à la masse un transistor de puissance du convertisseur, par exemple un transistor d'un oscillateur de puissance du convertisseur.The device then advantageously comprises a ramp generator and a modulator mainly comprising a comparator one of the inputs of which receives the signal from the ramp generator while the said DC control voltage is displayed on its other input so as to generate a chopped signal of constant potential but whose chopping rate varies as a function of the value of the displayed control potential, the chopping rate being zero when this potential is equal to the peak potential of the ramp generator and becoming all the greater that this potential is diminished. The chopped signal leaving the modulator is advantageously sent to a converter blocking circuit. The latter may advantageously include a transistor, the base of which receives the chopped signal and which makes it possible, when thus made conductive, to ground a converter power transistor, for example a transistor of a converter power oscillator. .

De préférence, le dispositif comporte un ciruit d'alimentation stabiliséepar le réseau continu pour permettre un fonctionnement stable de l'ensemble sur une grande plage de variation de la tension d'alimentation du réseau.Preferably, the device includes a circuit stabilized by the continuous network to allow stable operation of the assembly over a wide range of variation of the network supply voltage.

Selon un perfectionnement de l'invention, l'organe de commande peut être conçu de façon à ne pas adresser une tension inférieure à un certain seuil de façon à ne pas bloquer le convertisseur au-delà de la limite permettant un fonctionnement stable du tube fluorescent.According to an improvement of the invention, the control member can be designed so as not to address a voltage below a certain threshold so as not to block the converter beyond the limit allowing stable operation of the fluorescent tube .

D'autres avantages et caractéristiques de l'invention apparaîtront à la lecture de la description suivante, faite à titre d'exemple non limitatif et se référant au dessin annexé dans lequel :

  • La figure 1 représente un schéma d 'un dispositif selon l'invention.
  • La figure 2 représente un graphique du dispositif selon l'invention.
  • La ligne d'alimentation 1 du réseau continu, à la tension + Vcc., par exemple de 25 Volts, alimente un convertisseur de tube fluorescent comprenant un oscillateur de puissance usuel 2, par exemple construit autour d'un unique transistor dont le collecteur est chargé par le primaire accordé d'un transformateur à fuites 3, le secondaire du transformateur comprenant les enroulements haute tension et chauffage du tube fluorescent 4, la self de l'enroulement haute tension faisant office de ballast de régulateur de courant dans le tube. L'oscillateur est par exemple conçu pour avoir une fréquence de fonctionnement de l'ordre de 80 kHz afin de réduire la taille des composants volumineux tels que condensateurs et transformateurs.
  • Le dispositif de commande selon l'invention comprend tout d'abord un circuit d'alimentation stabilisée 5, par exemple à 15 Volts avec une résistance 6, une diode Zener 15 Volts 7 et un transistor 8 dont l'émetteur délivre la tension stabilisée de 15 Volts. Celle-ci alimente un générateur de rampe désigné dans son ensemble par 9 et un modulateur désigné dans son ensemble par 10. Le générateur de rampe , d'un type usuel, comprenant notamment un circuit intégré / par exemple du type 555, vendu par National Semi-Conductor , et réglé à 200 Hz, est relié à l'entrée (2) d'un comparateur 12 faisant partie du modulateur 10. L'autre entrée (3) du comparateur reçoit un conducteur 13 sur lequel on peut afficher une tension continue variable Uc grâce à un organe de commande approprié (non représenté), par exemple un système à trois positions, arrêt, marche à 100 % et marche à 25 %. L'entrée (3) du comparateur 12 est filtrée par un circuit RC et protégée par deux diodes 14, 15. La sortie 16 du comparateur est adressée à une interface de blocage de l'oscillateur 17, comprenant notamment un transistor 18 dont le collecteur est relié à la base du transistor de puissance (non représenté) de l'oscillateur 2 de sorte que, lorsque la tension requise est appliquée à la base du transistor 18, celui-ci débite etmet le transistor de l'oscillateur 2 à la masse. De façon avantageuse, le circuit de blocage 17 peut être relié au réseau d'alimentation 1 par une résistance 19 et comprendre également un moyen de filtrage RC.
Other advantages and characteristics of the invention will appear on reading the following description, given by way of nonlimiting example and referring to the appended drawing in which:
  • Figure 1 shows a diagram of a device according to the invention.
  • FIG. 2 represents a graph of the device according to the invention.
  • The supply line 1 of the DC network, at voltage + Vcc., For example of 25 Volts, supplies a fluorescent tube converter comprising a usual power oscillator 2, for example built around a single transistor whose collector is charged by the tuned primary of a leakage transformer 3, the secondary of the transformer comprising the high voltage windings and heating of the fluorescent tube 4, the choke of the high voltage winding acting as current regulator ballast in the tube. The oscillator is for example designed to have an operating frequency of the order of 80 kHz in order to reduce the size of large components such as capacitors and transformers.
  • The control device according to the invention firstly comprises a stabilized supply circuit 5, for example at 15 Volts with a resistor 6, a Zener diode 15 Volts 7 and a transistor 8, the emitter of which delivers the stabilized voltage of 15 Volts. This feeds a ramp generator designated as a whole by 9 and a modulator designated as a whole by 10. The generator ramp erector, of a usual type, comprising in particular an integrated circuit / for example of the 555 type, sold by National Semi-Conductor, and set to 200 Hz, is connected to the input (2) of a comparator 12 making part of the modulator 10. The other input (3) of the comparator receives a conductor 13 on which a variable direct voltage Uc can be displayed by means of an appropriate control member (not shown), for example a three-position system, stop, works at 100% and works at 25%. The input (3) of the comparator 12 is filtered by an RC circuit and protected by two diodes 14, 15. The output 16 of the comparator is addressed to a blocking interface of the oscillator 17, comprising in particular a transistor 18 including the collector is connected to the base of the power transistor (not shown) of oscillator 2 so that, when the required voltage is applied to the base of transistor 18, it supplies and puts the transistor of oscillator 2 to ground . Advantageously, the blocking circuit 17 can be connected to the supply network 1 by a resistor 19 and also include a filtering means RC.

Le fonctionnement est alors le suivant :

  • Lorsque la tension Uc appliquée par l'organe de commande est inférieure au potentiel initial de la rampe (3,5 V), c'est-à-dire si Uc < 3,5 V, le comparateur 12 génère une tension constante sur sa sortie 16 quel que soit le potentiel de rampe toujours < 3,5 V. Dans ces conditions, la base du transistor 18 est constamment excitée et le transistor 18 est rendu et maintenu conducteur. L'oscillateur de puissance ne peut donc pas fonctionner et le tube fluorescent reste éteint. Si ensuite, grâce à l'organe de commande, on applique une tension Uc supérieure à 9,5 V, potentiel final de rampe, par exemple 10 V ou plus, la sortie 16 du comparateur ne génère aucun signal. Le taux de découpage est nul, l'oscillateur de puissance fonctionne en permanence et le tube fluorescent est alimenté à 100 %.
The operation is as follows:
  • When the voltage Uc applied by the control member is lower than the initial potential of the ramp (3.5 V), that is to say if Uc <3.5 V, the comparator 12 generates a constant voltage on its output 16 whatever the ramp potential always <3.5 V. Under these conditions, the base of transistor 18 is constantly energized and transistor 18 is made and kept conductive. The power oscillator cannot therefore operate and the fluorescent tube remains off. If then, thanks to the control member, a voltage Uc is applied greater than 9.5 V, final ramp potential, for example 10 V or more, the output 16 of the comparator does not generate any signal. The chopping rate is zero, the power oscillator operates continuously and the fluorescent tube is 100% powered.

Si ensuite on affiche une tension Uc intermédiaire, par exemple 25 % (5 V), le comparateur 12 émettra un signal haché dont le taux de découpage, c'est-à-dire le rapport de la durée de potentiel nul du signal à la durée totale du signal, c'est-à-dire la période de la rampe, sera de 1/4. Ce signal adressé par le conducteur 16 au transistor 18 vient donc bloquer le convertisseur à une fréquence de 200 Hz pendant chaque fois les 3/4 de la période correspondant à cette fréquence. Il en résulte que l'intensité lumineuse dans le tube fluorescent sera d'environ 1/4 de l'intensité maximale.If then an intermediate voltage Uc is displayed, for example 25% (5 V), the comparator 12 will emit a chopped signal whose chopping rate, that is to say the ratio of the zero potential duration of the signal to the total signal duration, i.e. the ramp period, will be 1/4. This signal sent by the conductor 16 to the transistor 18 therefore blocks the converter at a frequency of 200 Hz for each time 3/4 of the period corresponding to this frequency. As a result, the light intensity in the fluorescent tube will be about 1/4 of the maximum intensity.

Bien entendu, l'invention est susceptible de nombreuses variantes. Tout d'abord, l'organe de commande destiné à adresser un potentiel de commande de Uc peut être piloté manuellement, ou au contraire asservi à un système quelconque. Il peut être constitué, de façon très simple, par un commutateur à trois positions permettant d'afficher par exemple un potentiel nul, un potentiel supérieur à 100 % du sommet de rampe et un potentiel intermédiaire , par exemple à 25 %. Il peut également être constitué par un potentiomètre à commande mécanique réglable sur des valeurs discrètes ou au contraire variable de façon continue. Il peut également être constitué par un circuit électronique permettant d'adresser, en fonction d'une instruction manuelle ou automatique, un potentiel déterminé Uc.Of course, the invention is susceptible of numerous variants. First of all, the control member intended to address a control potential of Uc can be controlled manually, or on the contrary controlled by any system. It can be constituted, very simply, by a three-position switch making it possible to display for example a zero potential, a potential greater than 100% of the top of the ramp and an intermediate potential, for example at 25%. It can also be constituted by a mechanically controlled potentiometer adjustable to discrete values or, on the contrary, continuously variable. It can also be constituted by an electronic circuit making it possible to address, according to a manual or automatic instruction, a determined potential Uc.

Les autres moyens électroniques représentés peuvent également être remplacés par des moyens équivalents accessibles à l'homme de l'art. L'interface 17 sera structurée en fonction de la nature et des caractéristiques du convertisseur qu'elle doit piloter, mlinterface 17 pouvant avantageusement être constituée par un module interchangeable ou réglable.The other electronic means shown can also be replaced by equivalent means accessible to those skilled in the art. The interface 17 will be structured as a function of the nature and characteristics of the converter which it must control, mlinterface 17 which can advantageously be constituted by an interchangeable or adjustable module.

Par ailleurs, il est intéressant, conformément à l'invention, d'empêcher l'illumination du tube fluorescent pour des taux de découpage élevés, par exemple supérieurs à 75 %, c'est-à-dire pour des valeurs où le fonctionnement stable du tube fluorescent ne peut plus être assuré. Ceci peut être obtenu par exemple en ne rendant l'entrée (3) du comparateur 12 sensible qu'à un potentiel égal ou supérieur à 5 V de façon à obtenir une zone interdite représentée en hachures sur la figure 2.Furthermore, it is advantageous, in accordance with the invention, to prevent the illumination of the fluorescent tube for high cutting rates, for example greater than 75%, that is to say for values where the function stable operation of the fluorescent tube can no longer be ensured. This can be obtained for example by making the input (3) of the comparator 12 sensitive only to a potential equal to or greater than 5 V so as to obtain a prohibited area shown in hatching in FIG. 2.

Claims (10)

1. Dispositif de commande de l'intensité lumineuse d'un tube fluorescent alimenté sur une tension continue par l'intermédiaire d'un convertisseur, dans lequel on fait varier la durée d'impulsionsde tension autorisant l'allumage du tube, caractérisé en ce qu'il comporte un organe de commande et des moyens (9,10) pour générer un signal haché avec un taux de découpage déterminé par ledit organe de commande, ledit signal haché étant adressé à un élément sensible (2) du convertisseur pour bloquer temporairement et de façon répétitive ledit convertisseur bloqué au rythme dudit signal haché.1. Device for controlling the light intensity of a fluorescent tube supplied with a DC voltage by means of a converter, in which the duration of voltage pulses authorizing the lighting of the tube is varied, characterized in that that it comprises a control member and means (9, 10) for generating a chopped signal with a chopping rate determined by said control member, said chopped signal being sent to a sensitive element (2) of the converter to temporarily block and repeatedly said converter blocked at the rate of said chopped signal. 2. Dispositif selon la revendication 1, caractérisé en ce que le blocage à rapport cyclique variable du convertisseur est effectué à basse fréquence, notamment de l'ordre de 200 Hz.2. Device according to claim 1, characterized in that the blocking at variable duty cycle of the converter is carried out at low frequency, in particular of the order of 200 Hz. 3. Dispositif selon l'une des revendications 1 et 2, caractérisé en ce que l'organe de commande est un organe permettant l'établissement d'une tension de commande continue.3. Device according to one of claims 1 and 2, characterized in that the control member is a member allowing the establishment of a continuous control voltage. 4. Dispositif selon la revendication 3, caractérisé en ce que l'organe de commande est un potentiomètre variable.4. Device according to claim 3, characterized in that the control member is a variable potentiometer. 5. Dispositif selon l'une des revendications 3 et 4, caractérisé en ce que l'organe de commande est alimenté à partir de la tension continue d'alimentation du réseau.5. Device according to one of claims 3 and 4, characterized in that the control member is supplied from the DC supply voltage of the network. 6. Dispositif selon l'une quelconque des revendications 3 à 5, caractérisé en ce qu'il comporte un générateur de rampe (9) et un modulateur (10) dont l'une des entrées reçoit le signal de rampe dudit générateur et l'autre ladite tension continue (Uc).6. Device according to any one of claims 3 to 5, characterized in that it comprises a ramp generator (9) and a modulator (10), one of the inputs of which receives the ramp signal from said generator and the other said direct voltage (Uc). 7. Dispositif selon la revendication 6, caractérisé en ce que le modulateur comporte un comparateur (12) dont le signal de sortie présente un taux de découpage variable en fonction de la valeur du potentiel (Uc) par rapport au potentiel de rampe.7. Device according to claim 6, characterized in that the modulator comprises a comparator (12) whose output signal has a chopping rate variable according to the value of the potential (Uc) compared to the ramp potential. 8. Dispositif selon l'une quelconque des: revendications 1 à 7, caractérisé en ce qu'il comporte un circuit de blocage (17) formant interface pour le convertisseur.8. Device according to any one of: Claims 1 to 7, characterized in that it comprises a blocking circuit (17) forming an interface for the converter. 9. Dispositif selon la revendication 8, caractérisé en ce que ledit circuit de blocage (17) comporte un transistor relié d'une part à la masse, d'autre part au convertisseur de puissance, la base du transistor recevant le signal haché.9. Device according to claim 8, characterized in that said blocking circuit (17) comprises a transistor connected on the one hand to ground, on the other hand to the power converter, the base of the transistor receiving the chopped signal. 10. Dispositif selon l'une quelconque des revendications 1 à 9, caractérisé en ce qu'il comporte des moyens d'interdiction empêchant la génération dudit signal tant que son taux de découpage possède une valeur élevée incompatible avec un fonctionnement stable du tube fluorescent.10. Device according to any one of claims 1 to 9, characterized in that it includes prohibition means preventing the generation of said signal as long as its chopping rate has a high value incompatible with stable operation of the fluorescent tube.
EP82402038A 1981-11-09 1982-11-05 Circuit for controlling the light intensity of a fluorescent lamp fed by a direct current Withdrawn EP0082031A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8120906A FR2516335B1 (en) 1981-11-09 1981-11-09 DEVICE FOR CONTROLLING THE LIGHT INTENSITY OF A FLUORESCENT TUBE SUPPLIED ON A CONTINUOUS VOLTAGE
FR8120906 1981-11-09

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EP0082031A1 true EP0082031A1 (en) 1983-06-22

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US (1) US4529913A (en)
EP (1) EP0082031A1 (en)
FR (1) FR2516335B1 (en)

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FR2778085A1 (en) 1998-04-30 1999-11-05 Fred Zacouto SKELETAL IMPLANT

Also Published As

Publication number Publication date
FR2516335B1 (en) 1985-06-07
US4529913A (en) 1985-07-16
FR2516335A1 (en) 1983-05-13

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