EP1040731A1 - Power device for illuminated light box - Google Patents

Power device for illuminated light box

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Publication number
EP1040731A1
EP1040731A1 EP98959995A EP98959995A EP1040731A1 EP 1040731 A1 EP1040731 A1 EP 1040731A1 EP 98959995 A EP98959995 A EP 98959995A EP 98959995 A EP98959995 A EP 98959995A EP 1040731 A1 EP1040731 A1 EP 1040731A1
Authority
EP
European Patent Office
Prior art keywords
converter
light box
network
supply
powering
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.)
Granted
Application number
EP98959995A
Other languages
German (de)
French (fr)
Other versions
EP1040731B1 (en
Inventor
Bernard Bedouet
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.)
Thales Avionics SAS
Original Assignee
Thales Avionics SAS
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 Thales Avionics SAS filed Critical Thales Avionics SAS
Publication of EP1040731A1 publication Critical patent/EP1040731A1/en
Application granted granted Critical
Publication of EP1040731B1 publication Critical patent/EP1040731B1/en
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
    • H05B41/285—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
    • H05B41/2853—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal power supply conditions

Definitions

  • the present invention relates to devices intended to supply electrical power to a light box, that is to say a fluorescent lighting system making it possible, for example, to illuminate by transmission a liquid crystal display screen.
  • Light boxes are known devices which make it possible to obtain, on a relatively large flat surface, generally of rectangular shape, light energy distributed in a very uniform manner making it possible to examine transparent objects.
  • a light box can be used for a variety of purposes, such as examining photographic negatives. It is also widely used to illuminate liquid crystal display screens which are used more and more in place of cathode ray tubes.
  • liquid crystal screens serve in particular as displays on board aircraft to give the pilot the information he needs, in particular the indications which were previously displayed using electromechanical indicators.
  • a light box used to illuminate a liquid crystal display screen in an aircraft consists, for the purposes of uniformity of lighting and light intensity, of a battery of fluorescent tubes aligned against each other the others and supplied with a high voltage, of the order of 1000 volts, delivered by a high voltage converter.
  • the term “light box” will denote in the following text the assembly composed of the battery of fluorescent tubes and its high voltage power converter. To obtain a very stable lighting, not presenting disturbing fluctuations for the operator, it is necessary to supply the light box by direct voltage, the value of which can be between 25 and 50 volts but must be very stable.
  • a supply device comprising a galvanically isolated regulated converter.
  • a power supply 1 01 supplies on the one hand a light box 1 02 and on the other hand a set of electronic cards 1 03 intended for the processing of information to be addressed to the LCD display screen not shown in this figure and which is fixed to the surface of the light box 1 02.
  • This light box 1 02 itself comprises in a known manner a set of fluorescent tubes 1 04 supplied by a high voltage converter comprising a cutter 1 05 and a step-up transformer 1 06.
  • the power supply device 1 01 operates from an input voltage + 28 volts, which we have seen that it is widely fluctuating. This charges, via an isolation diode 108, a set of capacitors 109. This diode makes it possible both to protect the equipment against reverse polarity and to avoid reverse discharge of the capacitors in the power supply network during power cuts. These capacitors themselves allow guarantee the supply of the downstream circuits during these possible interruptions.
  • the capacitors 1 09 also make it possible to supply two regulated voltage converters 1 1 0 and 1 1 1 intended respectively to supply the light box 1 02 and the electronic cards 1 03.
  • These capacitors are for example of the known type "Flybac” or “Forward” which we know the yield is between 80 and 85%. This efficiency, which might appear suitable in other circumstances, nevertheless has drawbacks in an aircraft where the available power is counted and where the heat from the corresponding losses must be dispersed.
  • converters of this type are relatively expensive and bulky.
  • the converter 1 1 0 is of the continuous-continuous regulator and step-up type with galvanic isolation. It provides the supply voltage of the light box 1 02. This supply voltage is for example 50 volts to be at the upper limit of variations in the supply voltage from the DC network + 28 volts.
  • the converter 1 1 1 is of the DC-DC regulator type with galvanic isolation and makes it possible to deliver all the voltages necessary for the electronic cards 1 03, for example + 5 volts + 1 5 volts and - 1 5 volts.
  • the invention provides a supply device for a light box from an unstable supply network, of the type comprising means of protection against reverse polarity and cuts in this network, a capacitor forming a reserve of energy and a DC-DC regulator converter to obtain from the network the stabilized supply voltage of the light box, mainly characterized in that this converter is directly supplied by the network, which 'It is of the booster type comprising an output diode which also plays the role of said protection means, and that said capacitor is connected directly at the output of the converter to be charged by the supply voltage of the light box.
  • the device further comprises a second DC-DC regulator converter of the step-down type with galvanic isolation to obtain from the output voltage of the first converter a set of stabilized supply voltages necessary for the electronic control cards of a display device lit by the light box and the connection between these cards and this device display is carried out with a galvanic isolation device.
  • the unstable supply network is of the 28 volt direct type and the supply voltage of the light box is substantially 50 volts.
  • FIG. 1 the diagram of a device according to the invention.
  • the device according to the invention shown diagrammatically in FIG. 1 comprises supply means 201 making it possible to deliver the supply voltages necessary for a light box 1 02 and for electronic control cards 1 03 which are identical to those of Figure 1.
  • the input voltage of the network + 28 volts is directly applied to a DC-regulator converter 204 which is of the boost boost type without galvanic isolation.
  • this converter very schematically comprises a series inductor 206 whose output is connected on the one hand to ground by a chopper 205 and on the other hand to a series diode 208 which directly delivers the output voltage of 50 volts required power supply to the light box 102.
  • This converter 204 makes it possible to compensate for variations in the 28 volt network with very good efficiency, which we know can reach a value of the order of 95% for a converter of this type.
  • the converter output diode 208 which participates in the voltage booster function, also makes it possible to carry out the function of protection against reverse polarity of the network and of blocking the reverse discharge of the energy reserve described below.
  • the output of the converter 204 is in fact applied to a capacitor 209, furthermore connected to ground, which makes it possible to store the energy necessary for the device supplied by the block 201 during the moments when the sector + 28 is cut, or else goes down to a value lower than that which allows the converter 204 to make up for the voltage difference.
  • this capacitor 209 which serves as an energy reserve, can be of a size significantly smaller than the capacitors 1 09, while making it possible to obtain the same protection duration with regard to cuts.
  • the output voltage of the converter 204 also makes it possible to supply a converter 1 1 1 of the continuous-continuous type regulator with galvanic isolation which is used to deliver the output voltages necessary for the cards 1 03, for example + 5 volts + 1 5 volts and - 1 5 volts.
  • This converter could be identical to the converter 1 1 1 of FIG. 1.
  • the electronic boards 1 03 are on the other hand supplied by the converter 1 1 1, which has a galvanic isolation. To ensure complete protection of these cards, galvanic protection must then be provided in the connection between them and the display screen located on the light box.
  • the invention therefore proposes to make this connection using interface means 21 0 which will make it possible to provide such galvanic isolation, for example by using transformers or known optically coupled systems.
  • the device according to the invention makes it possible to obtain the same results from the point of view of stability, resistance to cuts and galvanic isolation as in the known art, while presenting a remarkable simplicity of embodiment, while providing a much better efficiency and presenting a particularly reduced bulk and weight.

Landscapes

  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Dc-Dc Converters (AREA)
  • Cage And Drive Apparatuses For Elevators (AREA)

Abstract

The invention concerns powering devices for illuminated light boxes (102) for backlighting liquid crystal display screens, which consist in using a regulating boost DC/DC converter (204), directly powered by the 28 volt system for directly delivering the stabilised 50 volt direct current required for powering the illuminated light box. Said converter comprises an output diode (208) protecting the device. The power reserve is obtained by a capacitor (209) directly powered by the 50 volt current. A second converter (111) with galvanic insulation enables to obtain the power voltage allowance for powering the display screen lighted by the illuminated light box. The connection between these electronic control cards and the screen is produced by a galvanic insulation device (210). The invention enables to increase the powering device performance while reducing its weight, volume and price.

Description

DISPOSITIF D'ALIMENTATION POUR BOITE A LUMIERE SUPPLY DEVICE FOR LIGHT BOX
La présente invention se rapporte aux dispositifs destinés à alimenter en énergie électrique une boîte à lumière, c'est à dire un système d'éclairage fluorescent permettant par exemple d'éclairer par transmission un écran de visualisation à cristal liquide.The present invention relates to devices intended to supply electrical power to a light box, that is to say a fluorescent lighting system making it possible, for example, to illuminate by transmission a liquid crystal display screen.
Les boites à lumière sont des dispositifs connus qui permettent d'obtenir sur une surface plane relativement étendue, généralement de forme rectangulaire, une énergie lumineuse répartie de manière très uniforme permettant d'examiner des objets transparents.Light boxes are known devices which make it possible to obtain, on a relatively large flat surface, generally of rectangular shape, light energy distributed in a very uniform manner making it possible to examine transparent objects.
Une boîte à lumière peut servir à différents usages, par exemple à examiner des négatifs photographiques. Elle est également très utilisée pour éclairer par transparence les écrans de visualisation à cristal liquide qui sont de plus en plus utilisés à la place des tubes à rayons cathodiques.A light box can be used for a variety of purposes, such as examining photographic negatives. It is also widely used to illuminate liquid crystal display screens which are used more and more in place of cathode ray tubes.
Ces écrans à cristal liquide servent notamment d'afficheurs à bord des aéronefs pour donner au pilote les informations qui lui sont nécessaires, en particulier les indications qui étaient antérieurement affichées à l'aide d'indicateurs électromécaniques.These liquid crystal screens serve in particular as displays on board aircraft to give the pilot the information he needs, in particular the indications which were previously displayed using electromechanical indicators.
De manière connue, une boîte à lumière utilisée pour éclairer un écran de visualisation à cristal liquide dans un aéronef est constituée, pour des besoins d'uniformité d'éclairement et l'intensité lumineuse, d'une batterie du tubes fluorescents alignés les uns contre les autres et alimentés par une tension importante, de l'ordre de 1 000 volts, délivrée par un convertisseur haute tension .In known manner, a light box used to illuminate a liquid crystal display screen in an aircraft consists, for the purposes of uniformity of lighting and light intensity, of a battery of fluorescent tubes aligned against each other the others and supplied with a high voltage, of the order of 1000 volts, delivered by a high voltage converter.
Par souci de simplification on désignera dans la suite du texte sous le terme de boite à lumière l'ensemble composé de la batterie de tubes fluorescents et de son convertisseur d'alimentation haute tension. Pour obtenir un éclairage bien stable, ne présentant pas de fluctuations gênantes pour l'opérateur, il est nécessaire d'alimenter la boîte à lumière par une tension continue, dont la valeur peut être comprise entre 25 et 50 volts mais doit être bien stable.For the sake of simplification, the term “light box” will denote in the following text the assembly composed of the battery of fluorescent tubes and its high voltage power converter. To obtain a very stable lighting, not presenting disturbing fluctuations for the operator, it is necessary to supply the light box by direct voltage, the value of which can be between 25 and 50 volts but must be very stable.
On sait que dans les avions la tension continue disponible pour l'alimentation des organes de servitude est fournie par un réseau dit « 28 volts ». Cette appellation est tout à fait de convenance puisque, compte- tenu des différentes contraintes, la tension effective de ce réseau peut varier dans des limites importantes, comprises par exemple entre 1 2 et 50 volts. On ne peut donc pas alimenter directement la boîte à lumière à partir de ce réseau. En outre on est amené, pour éviter de se trouver confronté à des problèmes de boucles de masse entre primaire et secondaire de l'équipement, à réaliser un isolement galvanique entre le réseau 28 volts et la boîte à lumière.It is known that in aircraft the DC voltage available for supplying the service members is supplied by a so-called "28 volt" network. This designation is entirely appropriate since, taking into account the various constraints, the effective voltage of this network can vary within wide limits, for example between 1 2 and 50 volts. Therefore, the light box cannot be supplied directly from this network. In addition, in order to avoid being confronted with problems of ground loops between the primary and secondary of the equipment, we are led to carry out galvanic isolation between the 28 volt network and the light box.
Pour obtenir simultanément une régulation convenable de la tension d'alimentation de la boîte à lumière et un isolement de celle-ci par rapport au réseau, il est connu d'utiliser un dispositif d'alimentation comprenant un convertisseur à régulation isolé galvaniquement. Un tel dispositif est par exemple réalisé selon le schéma représenté sur la figure 1 annexée. Sur cette figure, une alimentation 1 01 alimente d'une part une boîte à lumière 1 02 et d'autre part un ensemble de cartes électroniques 1 03 destinées au traitement des informations à adresser à l'écran de visualisation LCD non représenté sur cette figure et qui est fixé à la surface de la boîte à lumière 1 02. Cette boîte à lumière 1 02 comprend elle-même de manière connue un ensemble de tubes fluorescents 1 04 alimentés par un convertisseur haute tension comprenant un découpeur 1 05 et un transformateur élévateur 1 06.In order to simultaneously obtain suitable regulation of the supply voltage of the light box and isolation of the latter from the network, it is known to use a supply device comprising a galvanically isolated regulated converter. Such a device is for example produced according to the diagram shown in Figure 1 attached. In this figure, a power supply 1 01 supplies on the one hand a light box 1 02 and on the other hand a set of electronic cards 1 03 intended for the processing of information to be addressed to the LCD display screen not shown in this figure and which is fixed to the surface of the light box 1 02. This light box 1 02 itself comprises in a known manner a set of fluorescent tubes 1 04 supplied by a high voltage converter comprising a cutter 1 05 and a step-up transformer 1 06.
Le dispositif d'alimentation 1 01 fonctionne à partir d'une tension d'entrée + 28 volts, dont on a vu qu'elle était largement fluctuante. Celle-ci charge, par l'intermédiaire d'une diode d'isolement 108, un ensemble de condensateurs 109. Cette diode permet à la fois de protéger l'équipement contre les inversions de polarité et d'éviter une décharge inverse des condensateurs dans le réseau d'alimentation lors des coupures de celui-ci . Ces condensateurs eux-mêmes permettent de garantir l'alimentation des circuits avals pendant ces éventuelles coupures.The power supply device 1 01 operates from an input voltage + 28 volts, which we have seen that it is widely fluctuating. This charges, via an isolation diode 108, a set of capacitors 109. This diode makes it possible both to protect the equipment against reverse polarity and to avoid reverse discharge of the capacitors in the power supply network during power cuts. These capacitors themselves allow guarantee the supply of the downstream circuits during these possible interruptions.
Les condensateurs 1 09 permettent en outre d'alimenter deux convertisseurs de tension régulés 1 1 0 et 1 1 1 destinés à alimenter respectivement la boîte à lumière 1 02 et les cartes électroniques 1 03. Ces condensateurs sont par exemple du type connu « Flybac » ou « Forward » dont on sait que le rendement est compris entre 80 et 85 % . Ce rendement, qui pourrait paraître convenable dans d'autres circonstances, présente néanmoins des inconvénients au niveau d'un aéronef où la puissance disponible est comptée et où il faut disperser la chaleur provenant des pertes correspondantes. En outre les convertisseurs de ce type sont relativement onéreux et volumineux.The capacitors 1 09 also make it possible to supply two regulated voltage converters 1 1 0 and 1 1 1 intended respectively to supply the light box 1 02 and the electronic cards 1 03. These capacitors are for example of the known type "Flybac" or "Forward" which we know the yield is between 80 and 85%. This efficiency, which might appear suitable in other circumstances, nevertheless has drawbacks in an aircraft where the available power is counted and where the heat from the corresponding losses must be dispersed. In addition, converters of this type are relatively expensive and bulky.
Le convertisseur 1 1 0 est du type continu-continu régulateur et élévateur avec isolation galvanique. Il permet de fournir la tension d'alimentation de la boite à lumière 1 02. Cette tension d'alimentation est par exemple de 50 volts pour être en limite haute des variations de la tension d'alimentation provenant du réseau continu + 28 volts.The converter 1 1 0 is of the continuous-continuous regulator and step-up type with galvanic isolation. It provides the supply voltage of the light box 1 02. This supply voltage is for example 50 volts to be at the upper limit of variations in the supply voltage from the DC network + 28 volts.
Le convertisseur 1 1 1 est du type continu-continu régulateur avec isolation galvanique et permet de délivrer l'ensemble des tensions nécessaires aux cartes électroniques 1 03, par exemple + 5 volts + 1 5 volts et - 1 5 volts.The converter 1 1 1 is of the DC-DC regulator type with galvanic isolation and makes it possible to deliver all the voltages necessary for the electronic cards 1 03, for example + 5 volts + 1 5 volts and - 1 5 volts.
Pour pallier les inconvénients d'une telle structure, l'invention propose un dispositif d'alimentation pour boîte à lumière à partir d'un réseau d'alimentation instable, du type comprenant des moyens de protection contre les inversions de polarité et les coupures de ce réseau, un condensateur formant réserve d'énergie et un convertisseur continu- continu régulateur pour obtenir à partir du réseau la tension d'alimentation stabilisée de la boîte à lumière, principalement caractérisé en ce que ce convertisseur est directement alimenté par le réseau, qu'il est du type élévateur comportant une diode de sortie qui joue en outre le rôle des dits moyens de protection, et que ledit condensateur est connecté directement en sortie du convertisseur pour être chargé par la tension d'alimentation de la boîte à lumière.To overcome the drawbacks of such a structure, the invention provides a supply device for a light box from an unstable supply network, of the type comprising means of protection against reverse polarity and cuts in this network, a capacitor forming a reserve of energy and a DC-DC regulator converter to obtain from the network the stabilized supply voltage of the light box, mainly characterized in that this converter is directly supplied by the network, which 'It is of the booster type comprising an output diode which also plays the role of said protection means, and that said capacitor is connected directly at the output of the converter to be charged by the supply voltage of the light box.
Selon une autre caractéristique, le dispositif comprend en outre un deuxième convertisseur continu-continu régulateur du type abaisseur à isolement galvanique pour obtenir à partir de la tension de sortie du premier convertisseur un jeu de tensions stabilisées d'alimentation nécessaire aux cartes électroniques de commande d'un dispositif de visualisation éclairé par la boîte à lumière et la liaison entre ces cartes et ce dispositif de visualisation s'effectue avec un dispositif d'isolement galvanique.According to another characteristic, the device further comprises a second DC-DC regulator converter of the step-down type with galvanic isolation to obtain from the output voltage of the first converter a set of stabilized supply voltages necessary for the electronic control cards of a display device lit by the light box and the connection between these cards and this device display is carried out with a galvanic isolation device.
Selon une autre caractéristique, le réseau d'alimentation instable est du type 28 volts continu et la tension d'alimentation de la boîte à lumière est de sensiblement 50 volts. D'autres particularités et avantages de l'invention apparaîtront clairement dans la description suivante, présentée à titre d'exemple non limitatif en regard des figures annexées qui représentent :According to another characteristic, the unstable supply network is of the 28 volt direct type and the supply voltage of the light box is substantially 50 volts. Other features and advantages of the invention will appear clearly in the following description, presented by way of nonlimiting example with reference to the appended figures which represent:
- la figure 1 , le schéma d'un dispositif connu; et- Figure 1, a diagram of a known device; and
- la figure 2, le schéma d'un dispositif selon l'invention. Le dispositif selon l'invention représenté schématiquement sur la figure 1 comprend des moyens d'alimentation 201 permettant de délivrer les tensions d'alimentations nécessaires à une boîte à lumière 1 02 et à des cartes électroniques 1 03 de commande qui sont identiques à celles de la figure 1 . Selon l'invention par contre, dans le dispositif 201 la tension d'entrée du réseau + 28 volts est directement appliquée à un convertisseur continu-continu régulateur 204 qui est du type « boost » élévateur sans isolement galvanique.- Figure 2, the diagram of a device according to the invention. The device according to the invention shown diagrammatically in FIG. 1 comprises supply means 201 making it possible to deliver the supply voltages necessary for a light box 1 02 and for electronic control cards 1 03 which are identical to those of Figure 1. According to the invention on the other hand, in the device 201 the input voltage of the network + 28 volts is directly applied to a DC-regulator converter 204 which is of the boost boost type without galvanic isolation.
De manière connue, ce convertisseur comprend très schématiquement une inductance série 206 dont la sortie est reliée d'une part à la masse par un découpeur 205 et d'autre part à une diode série 208 qui délivre directement la tension de sortie de 50 volts nécessaire à l'alimentation de la boite à lumière 102.In known manner, this converter very schematically comprises a series inductor 206 whose output is connected on the one hand to ground by a chopper 205 and on the other hand to a series diode 208 which directly delivers the output voltage of 50 volts required power supply to the light box 102.
Ce convertisseur 204 permet de compenser les variations du réseau 28 volts avec un très bon rendement, dont on sait qu'il peut atteindre pour un convertisseur de ce type une valeur de l'ordre de 95 % .This converter 204 makes it possible to compensate for variations in the 28 volt network with very good efficiency, which we know can reach a value of the order of 95% for a converter of this type.
En outre la diode 208 de sortie du convertisseur, qui participe à la fonction élévateur de tension, permet de réaliser également la fonction de protection contre les inversions de polarité du réseau et de blocage de la décharge inverse de la réserve d'énergie décrite plus loin. La sortie du convertisseur 204 est en effet appliquée à un condensateur 209, relié par ailleurs à la masse, qui permet de stocker l'énergie nécessaire au dispositif alimenté par le bloc 201 pendant les instants ou le secteur + 28 est coupé, ou bien descend à une valeur inférieure à celle qui permet au convertisseur 204 de rattraper la différence de tension.In addition, the converter output diode 208, which participates in the voltage booster function, also makes it possible to carry out the function of protection against reverse polarity of the network and of blocking the reverse discharge of the energy reserve described below. . The output of the converter 204 is in fact applied to a capacitor 209, furthermore connected to ground, which makes it possible to store the energy necessary for the device supplied by the block 201 during the moments when the sector + 28 is cut, or else goes down to a value lower than that which allows the converter 204 to make up for the voltage difference.
En raison de la tension plus importante en sortie de ce convertisseur 204 qu'en sortie de la diode 1 08 de la figure 1 , ce condensateur 209, qui sert de réserve d'énergie, peut être d'une taille nettement plus réduite que les condensateurs 1 09, tout en permettant d'obtenir une même durée de protection vis à vis des coupures.Because of the higher voltage at the output of this converter 204 than at the output of the diode 108 of FIG. 1, this capacitor 209, which serves as an energy reserve, can be of a size significantly smaller than the capacitors 1 09, while making it possible to obtain the same protection duration with regard to cuts.
La tension de sortie du convertisseur 204 permet en outre d'alimenter un convertisseur 1 1 1 du type continu-continu régulateur à isolement galvanique qui sert à délivrer les tensions de sortie nécessaires aux cartes 1 03, par exemple + 5 volts + 1 5 volts et - 1 5 volts.The output voltage of the converter 204 also makes it possible to supply a converter 1 1 1 of the continuous-continuous type regulator with galvanic isolation which is used to deliver the output voltages necessary for the cards 1 03, for example + 5 volts + 1 5 volts and - 1 5 volts.
Ce convertisseur pourra être identique au convertisseur 1 1 1 de la figure 1 .This converter could be identical to the converter 1 1 1 of FIG. 1.
On constate alors que dans cette solution il n'y a plus d'isolement galvanique entre la boite à lumière 1 02 et le secteur + 28 volts continu.We then see that in this solution there is no longer any galvanic isolation between the light box 1 02 and the + 28 volts DC sector.
Ceci ne présentent pas d'inconvénients puisque la boite à lumière proprement dite ne comporte pas de circuits logiques susceptibles d'être affectés par un tel défaut d'isolement galvanique.This does not have any drawbacks since the light box itself does not include logic circuits liable to be affected by such a defect in galvanic isolation.
Les cartes électroniques 1 03 sont par contre alimentées par le convertisseur 1 1 1 , qui présente lui un isolement galvanique. Pour assurer alors une protection complète de ces cartes il convient alors d'assurer une protection galvanique dans la liaison entre celles-ci et l'écran de visualisation située sur la boite à lumière. L'invention propose donc de réaliser cette liaison à l'aide de moyens d'interface 21 0 qui permettront de fournir une telle isolation galvanique, par exemple en utilisant des transformateurs ou des systèmes à couplage optique connus.The electronic boards 1 03 are on the other hand supplied by the converter 1 1 1, which has a galvanic isolation. To ensure complete protection of these cards, galvanic protection must then be provided in the connection between them and the display screen located on the light box. The invention therefore proposes to make this connection using interface means 21 0 which will make it possible to provide such galvanic isolation, for example by using transformers or known optically coupled systems.
En conclusion, le dispositif selon l'invention permet d'obtenir les mêmes résultats au point de vue stabilité, résistance aux coupures et isolement galvanique que dans l'art connu, tout en présentant une simplicité de réalisation remarquable, en procurant un bien meilleur rendement et en présentant un encombrement et un poids particulièrement réduits. In conclusion, the device according to the invention makes it possible to obtain the same results from the point of view of stability, resistance to cuts and galvanic isolation as in the known art, while presenting a remarkable simplicity of embodiment, while providing a much better efficiency and presenting a particularly reduced bulk and weight.

Claims

REVENDICATIONS
1 - Dispositif d'aiimentation pour boîte à lumière ( 1 02) à partir d'un réseau d'alimentation instable, du type comprenant des moyens de protection contre les inversions de polarité et les coupures de ce réseau, un condensateur formant réserve d'énergie et un convertisseur continu- continu régulateur pour obtenir à partir du réseau la tension d'alimentation stabilisée de la boîte à lumière, caractérisé en ce que ce convertisseur (204) est directement alimenté par le réseau, qu'il est du type élévateur comportant une diode de sortie (208) qui joue en outre le rôle des dits moyens de protection, et que ledit condensateur (209) est connecté directement en sortie du convertisseur pour être chargé par la tension d'alimentation de la boîte à lumière.1 - Supply device for light box (1 02) from an unstable supply network, of the type comprising means of protection against reverse polarity and cuts in this network, a capacitor forming a reserve of energy and a DC-regulator converter for obtaining from the network the stabilized supply voltage of the light box, characterized in that this converter (204) is directly supplied by the network, that it is of the booster type comprising an output diode (208) which also plays the role of said protection means, and that said capacitor (209) is connected directly at the output of the converter to be charged by the supply voltage of the light box.
2 - Dispositif selon la revendication 1 , caractérisé en ce qu'il comprend en outre au moins un deuxième convertisseur continu-continu régulateur (1 1 1 ) du type abaisseur à isolement galvanique pour obtenir à partir de la tension de sortie du premier convertisseur un jeu de tensions stabilisées d'alimentation nécessaire aux cartes électroniques de commande ( 1 03) d'un dispositif de visualisation éclairé par la boîte à lumière et en ce que la liaison entre ces cartes et ce dispositif de visualisation s'effectue avec un dispositif d'isolement galvanique (21 0) .2 - Device according to claim 1, characterized in that it further comprises at least one second DC-DC regulator converter (1 1 1) of the step-down type with galvanic isolation to obtain from the output voltage of the first converter a set of stabilized supply voltages necessary for the electronic control cards (1 03) of a display device lit by the light box and in that the connection between these cards and this display device is effected with a device galvanic isolation (21 0).
3 -Dispositif selon l'une quelconque des revendications 1 et 2 caractérisé en ce que le réseau d'alimentation instable est du type 28 volts continu et que la tension d'alimentation de la boîte à lumière ( 1 02) est de sensiblement 50 volts. 3 -A device according to any one of claims 1 and 2 characterized in that the unstable supply network is of the 28 volt DC type and that the supply voltage of the light box (1 02) is substantially 50 volts .
EP98959995A 1997-12-16 1998-12-15 Power device for illuminated light box Expired - Lifetime EP1040731B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9715949A FR2772525B1 (en) 1997-12-16 1997-12-16 SUPPLY DEVICE FOR LIGHT BOX
FR9715949 1997-12-16
PCT/FR1998/002739 WO1999031940A1 (en) 1997-12-16 1998-12-15 Power device for illuminated light box

Publications (2)

Publication Number Publication Date
EP1040731A1 true EP1040731A1 (en) 2000-10-04
EP1040731B1 EP1040731B1 (en) 2001-10-17

Family

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Application Number Title Priority Date Filing Date
EP98959995A Expired - Lifetime EP1040731B1 (en) 1997-12-16 1998-12-15 Power device for illuminated light box

Country Status (6)

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US (1) US6288912B1 (en)
EP (1) EP1040731B1 (en)
DE (1) DE69802114T2 (en)
ES (1) ES2163305T3 (en)
FR (1) FR2772525B1 (en)
WO (1) WO1999031940A1 (en)

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FR2815789B1 (en) * 2000-10-24 2003-01-31 Thomson Csf HIGH SECURITY POWER SUPPLY DEVICE
TWI341511B (en) * 2006-11-03 2011-05-01 Chimei Innolux Corp Power supply circuit
TWM314869U (en) * 2006-11-27 2007-07-01 Innolux Display Corp Power supply circuit for liquid crystal display device and liquid crystal display device using same
TWI324435B (en) * 2006-12-29 2010-05-01 Innolux Display Corp Inverter circuit
US9291683B2 (en) 2011-10-11 2016-03-22 General Electric Company Power module protection at start-up

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US4450384A (en) * 1982-08-04 1984-05-22 Mole-Richardson Company DC Light dimmer control system
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Also Published As

Publication number Publication date
US6288912B1 (en) 2001-09-11
FR2772525B1 (en) 2000-03-17
EP1040731B1 (en) 2001-10-17
DE69802114T2 (en) 2002-06-06
WO1999031940A1 (en) 1999-06-24
FR2772525A1 (en) 1999-06-18
ES2163305T3 (en) 2002-01-16
DE69802114D1 (en) 2001-11-22

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