EP0609155A2 - Shielding device for a switching power supply transformer - Google Patents

Shielding device for a switching power supply transformer Download PDF

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Publication number
EP0609155A2
EP0609155A2 EP94400705A EP94400705A EP0609155A2 EP 0609155 A2 EP0609155 A2 EP 0609155A2 EP 94400705 A EP94400705 A EP 94400705A EP 94400705 A EP94400705 A EP 94400705A EP 0609155 A2 EP0609155 A2 EP 0609155A2
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EP
European Patent Office
Prior art keywords
transformer
shielding device
power supply
switching power
ferrite core
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
EP94400705A
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German (de)
French (fr)
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EP0609155B1 (en
EP0609155A3 (en
Inventor
Jean-Yves Buatois
Jean-Michel Bouillot
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Thomson Television Components France SA
Original Assignee
Orega Electronique et Mecanique
Thomson Television Components France SA
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Publication of EP0609155A2 publication Critical patent/EP0609155A2/en
Publication of EP0609155A3 publication Critical patent/EP0609155A3/en
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Publication of EP0609155B1 publication Critical patent/EP0609155B1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/36—Electric or magnetic shields or screens
    • H01F27/363—Electric or magnetic shields or screens made of electrically conductive material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F5/00—Coils
    • H01F5/02—Coils wound on non-magnetic supports, e.g. formers
    • H01F2005/022—Coils wound on non-magnetic supports, e.g. formers wound on formers with several winding chambers separated by flanges, e.g. for high voltage applications

Definitions

  • the present invention relates to an electromagnetic shielding device for switching power supply transformer.
  • Switching power supplies currently equip the vast majority of televisions and monitors for computer installations. Each of these power supplies is provided with a transformer placed on a chassis, which is itself positioned below the cathode ray tube of the television or monitor.
  • a first shielding device currently existing on these transformers, is constituted by a metal cover which completely envelops the transformer, which of course gives an excellent result from the point of view of protection against the abovementioned image pollution.
  • this is a large volume item, expensive in manufacturing cost (if only by the price of the raw material).
  • this very enveloping cover tends to reduce the safety distances between the two primary and secondary circuits of the transformer, because it passes close to certain cable or wire outlets: to comply with the mandatory standards of galvanic isolation, it is then most of the time necessary to insulate the interior of this metal cover by depositing a layer of insulating material.
  • Another shielding solution consists in providing a magnetic loop, constituted by an annular copper strip which encloses the middle part of the transformer in parallel to the plate on which its output pins are soldered.
  • this shielding ring Being a transformer in "layers" mode, the positioning of this shielding ring is carried out directly by narrow winding and welding of this loop around the "belly" of the transformer (that is to say around of the part which has its winding).
  • This solution gives satisfactory results from the point of view of electromagnetic protection, but however less good than that obtained by the aforementioned total shielding.
  • it remains expensive, since it is an attached part which must be placed with precision around the transformer, by enclosing it tightly to avoid any risk of displacement (such a risk would be contrary to safety standards), and on which one must engage in a welding operation to guarantee its short-circuiting.
  • transformers in layered mode tend more and more to be replaced by transformers in "pancake” mode, for obvious reasons of ease of automation of their manufacturing mode.
  • a transformer of this type is shown, with general reference 1 in Figure 1 attached.
  • the ferrite core of the transformer is designated by the reference 2, the "pancakes" by 3, the wires which they guide and support by 4, and the transformer input / output pins by 5.
  • the invention aims to remedy these drawbacks.
  • a switching power supply transformer intended in particular to equip a television set or a monitor, this device consisting of a single metal part in the form of a bowl or dish, with a flat bottom. and with edges directed downwards, adapting above the transformer, in order to ensure the electromagnetic protection of this transformer so that this metal part can be easily placed, and fixed for example by gluing, on this ferrite core .
  • edges are chosen to be of sufficiently small width so as not to affect the galvanic isolation provided by the transformer, but nevertheless large enough to allow on the one hand easy place (for example by robot) of this cup on the top of the transformer and on the other hand provide the desired electromagnetic protection.
  • This part is preferably produced by stamping. It is placed on the ferrite core after prior deposit of glue on it (one or two points of glue for example), this glue is advantageously the same as that used to bond the elements of this ferrite core to each other. These bonding and positioning operations are easily carried out by an automatic robotization chain.
  • FIG. 2 represents, in perspective and in scale 1, this shielding device and its mode of installation on a switching power supply transformer.
  • the switching power supply transformer 1 of FIG. 1 is shown there in perspective, with its ferrite core 2, its wafers 3, its connection wires 4, and its input pins / exit 5.
  • the electromagnetic shielding device is constituted by a bowl, or cup, 7 made of copper, produced by stamping.
  • the flat bottom 8 of this cup is rectangular and has the same external dimensions as those of the upper rectangular face 9 of the ferrite core 2.
  • the cup 7 can be made of Al, brass, etc.
  • edges 10 of the cup 7 are flared, with an angular slope ⁇ relative to the axis perpendicular to the plane of the bottom 8 which, being of the order of 15 to 20 degrees for example, is optimized both to allow the easy automatic fitting of the cap 7 on the top of the transformer 1 (as indicated in dashed lines on the drawing) with the edges 10 facing downwards, and to ensure the desired electromagnetic protection.
  • the width L of these edges 10 is chosen to be small (of the order of a few millimeters for example): it must be sufficient to facilitate as much as possible the positioning of the cup 7 on the upper face 9 of the core 2, but not too much important for, while ensuring the electromagnetic protection desired, comply with the galvanic protection standards of the transformer.
  • the simple shape, without cuts or roughness risking to catch pieces to each other, of the shielding cup 7, and its small size allow its easy feeding in a robotic automatic chain, with vibrating bowl, without modification. sensitive manufacturing lines.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
  • Insulators (AREA)

Abstract

Electromagnetic screening for a switched-mode power supply transformer (1) particularly for a television set or for a monitor. It consists of a cap produced in the form of a flat-bottomed (8) tray (7), having flared ( alpha ) edges (10) of relatively narrow width (L). It is placed automatically on the upper face (9) of the ferrite core (2), the shape of which it follows, with the prior deposition of two drops of glue (11, 12). This glue is the same as that used for joining (13) the ferrite core (2). <IMAGE>

Description

La présente invention se rapporte à un dispositif de blindage électromagnétique pour transformateur d'alimentation à découpage.The present invention relates to an electromagnetic shielding device for switching power supply transformer.

Les alimentations à découpage équipent actuellement la grande majorité des téléviseurs et des moniteurs pour installations informatiques. Chacune de ces alimentations est pourvue d'un transformateur placé sur un chassis, qui est lui même positionné en dessous du tube cathodique du téléviseur ou du moniteur.Switching power supplies currently equip the vast majority of televisions and monitors for computer installations. Each of these power supplies is provided with a transformer placed on a chassis, which is itself positioned below the cathode ray tube of the television or monitor.

Ces alimentations fonctionnent par hachage, ou découpage, du courant, et ce découpage a pour effet néfaste d'induire, au niveau du transformateur, des rayonnements électromagnétiques parasites qui viennent agir sur les récepteurs électromagnétiques que constituent en particulier les bobines déflectrices du tube cathodique. Il en résulte des perturbations d'image qui sont plus ou moins importantes, c'est-à-dire plus ou moins visibles, selon la valeur de la fréquence de découpage, la position géographique du transformateur, et la sensibilité des bobines déflectrices.These power supplies operate by chopping, or cutting, the current, and this cutting has the harmful effect of inducing, at the level of the transformer, parasitic electromagnetic radiation which comes to act on the electromagnetic receivers which constitute in particular the deflection coils of the cathode ray tube. This results in image disturbances which are more or less significant, that is to say more or less visible, depending on the value of the switching frequency, the geographic position of the transformer, and the sensitivity of the deflection coils.

Dans le cas où il s'agit d'une fréquence de découpage synchronisée et de valeur fixe, ces perturbations électromagnétiques existent bien, mais elles ne se matérialisent fort heureusement pas sur l'écran car elles apparaissent pendant un laps de temps où le spot balayage est sur sa phase de retour.In the case where it is a synchronized switching frequency and of fixed value, these electromagnetic disturbances do exist, but they fortunately do not materialize on the screen because they appear during a period of time when the spot scanning is on its return phase.

En revanche, certaines alimentations à découpage fonctionnent à une fréquence qui varie de manière importante en fonction de la puissance électrique demandée par le téléviseur ou le moniteur, en fonction de sa tension d'alimentation, et en fonction de ce qui va être demandé au transformateur. Cette fréquence de découpage varie alors constamment, et il en résulte un phénomène de battement entre cette dernière et la fréquence, fixe, de balayage du spot du téléviseur ou du moniteur. Ce battement de fréquences produit sur l'écran un phénomène de pollution d'image qui se traduit visuellement par un "moirage" horizontal plus ou moins sombre, c'est-à-dire par une bande grisâtre qui défile sur l'écran du tube cathodique, ce qui n'est bien entendu pas admissible dans la grande majorité des cas. Comme il n'est généralement pas possible de déplacer géographiquement le transformateur de découpage d'une distance suffisante (il faudrait alors le sortir complètement du chassis du téléviseur ou du moniteur), il convient de trouver une autre solution pour remédier à ce phénomène de pollution d'image.On the other hand, certain switching power supplies operate at a frequency which varies significantly depending on the electrical power requested by the television or the monitor, according to its supply voltage, and according to what will be asked of the transformer. . This chopping frequency then varies constantly, and this results in a phenomenon of beat between the latter and the fixed frequency of TV or monitor spot scan. This beat of frequencies produces on the screen a phenomenon of image pollution which is reflected visually by a more or less dark horizontal "moire", that is to say by a grayish band which scrolls on the screen of the tube cathodic, which is of course not admissible in the vast majority of cases. As it is generally not possible to move the switching transformer geographically a sufficient distance (it would then have to be completely removed from the chassis of the television or monitor), another solution should be found to remedy this pollution phenomenon image.

Il serait pensable, en premier lieu, d'inverser le champ électromagnétique parasite émis par le transformateur de découpage, en inversant ses bobinages pour déplacer ce champ. Un tel palliatif s'avère malheureusement insuffisant pour éviter efficacement la pollution d'image précitée, et il convient donc finalement de prévoir un dispositif de blindage de ce transformateur.It would be conceivable, firstly, to reverse the parasitic electromagnetic field emitted by the switching transformer, by reversing its coils to move this field. Such a palliative unfortunately turns out to be insufficient to effectively avoid the aforementioned image pollution, and it is therefore ultimately necessary to provide a shielding device for this transformer.

Un premier dispositif de blindage, existant actuellement sur ces transformateurs, est constitué par un capot métallique qui enveloppe totalement le transformateur, ce qui donne bien entendu un excellent résultat du point de vue de la protection contre les pollutions d'image précitées. Il s'agit cependant là d'une pièce de grand volume, onéreuse en coût de fabrication (ne serait-ce que par le prix de la matière première). En outre, ce capot très enveloppant tend à réduire les distances de sécurité entre les deux circuits primaire et secondaire du transformateur, car il passe à proximité de certaines sorties de câble ou de fils : pour respecter les normes obligatoires d'isolement galvanique, il est alors la plupart du temps nécessaire d'isoler l'intérieur de ce capot métallique par le dépôt d'une couche de matériau isolant. Il est en outre généralement nécessaire d'isoler de la même façon sa partie extérieure, car ce capot arrive souvent à une distance des composants électroniques, situés sur la platine du téléviseur, qui est trop faible pour respecter les normes de sécurité. Il en résulte une augmentation du prix de revient, déjà élevé, de cette pièce de blindage.A first shielding device, currently existing on these transformers, is constituted by a metal cover which completely envelops the transformer, which of course gives an excellent result from the point of view of protection against the abovementioned image pollution. However, this is a large volume item, expensive in manufacturing cost (if only by the price of the raw material). In addition, this very enveloping cover tends to reduce the safety distances between the two primary and secondary circuits of the transformer, because it passes close to certain cable or wire outlets: to comply with the mandatory standards of galvanic isolation, it is then most of the time necessary to insulate the interior of this metal cover by depositing a layer of insulating material. It is also generally necessary to isolate in the same way its external part, because this cover often arrives at a distance from the electronic components, located on the plate of the television set, which is too weak to respect the safety standards. This results in an increase in the cost price, already high, of this shielding part.

Une autre solution de blindage consiste à prévoir une boucle magnétique, constituée par une bande annulaire en cuivre qui enserre la partie médiane du transformateur de manière parallèle à la platine sur laquelle ses broches de sortie sont soudées.Another shielding solution consists in providing a magnetic loop, constituted by an annular copper strip which encloses the middle part of the transformer in parallel to the plate on which its output pins are soldered.

S'agissant d'un transformateur en mode "couches", la mise en place de cet anneau de blindage s'effectue directement par enroulement étroit et soudage de cette boucle autour du "ventre" du transformateur (c'est-à-dire autour de la partie qui comporte son bobinage). Cette solution donne des résultats satisfaisants du point de vue de la protection électromagnétique, mais toutefois moins bons que celui obtenu par le blindage total précité. Elle reste malgré tout onéreuse, car il s'agit d'une pièce rapportée qui doit être placée avec précision autour du transformateur, en l'enserrant étroitement pour éviter tout risque de déplacement (un tel risque serait contraire aux normes de sécurité), et sur laquelle on doit se livrer à une opération de soudure pour garantir sa mise en court-circuit.Being a transformer in "layers" mode, the positioning of this shielding ring is carried out directly by narrow winding and welding of this loop around the "belly" of the transformer (that is to say around of the part which has its winding). This solution gives satisfactory results from the point of view of electromagnetic protection, but however less good than that obtained by the aforementioned total shielding. However, it remains expensive, since it is an attached part which must be placed with precision around the transformer, by enclosing it tightly to avoid any risk of displacement (such a risk would be contrary to safety standards), and on which one must engage in a welding operation to guarantee its short-circuiting.

Par ailleurs, ces transformateurs en mode couches tendent de plus en plus à être remplacés par des transformateurs en mode "galettes", pour des raisons évidentes de facilité d'automatisation de leur mode de fabrication. Un transformateur de ce type est représenté, sous référence générale 1 sur la figure 1 jointe.Furthermore, these transformers in layered mode tend more and more to be replaced by transformers in "pancake" mode, for obvious reasons of ease of automation of their manufacturing mode. A transformer of this type is shown, with general reference 1 in Figure 1 attached.

Sur cette figure, le noyau de ferrite du transformateur est désigné par la référence 2, les "galettes" par 3, les fils qu'elles guident et supportent par 4, et les broches d'entrées/sorties du transformateur par 5.In this figure, the ferrite core of the transformer is designated by the reference 2, the "pancakes" by 3, the wires which they guide and support by 4, and the transformer input / output pins by 5.

Pour un tel transformateur, il n'est bien évidemment pas possible de prévoir un ruban métallique court-circuité lui enserrant le ventre, car les galettes 3 sont pourvues de parties saillantes de forme tourmentée. La solution qui est alors adoptée consiste à prévoir un capot 6 en matière plastique, qui enveloppe totalement le transformateur 1 comme représenté au dessin, et autour duquel a été préalablement fixée une boucle métallique de blindage 7, semblable en hauteur et épaisseur à celles prévues pour les transformateurs de type couche. Cette pièce 6, 7 vient se fixer par encliquetage sue le transformateur 1. Il s'agit encore là d'une pièce qui, comme la précédente, est onéreuse en coût de fabrication, et qui se prête mal à une mise en place automatique sur une chaîne de fabrication de ces transformateurs de découpage. En outre, comme dans le cas précédent, les performances de protection électromagnétique obtenues ne sont pas absolument parfaites.For such a transformer, it is obviously not possible to provide a short-circuited metallic strip enclosing the belly, because the wafers 3 are provided with protruding parts of tormented shape. The solution which is then adopted consists in providing a cover 6 made of plastic material, which completely envelops the transformer 1 as shown in the drawing, and around which a metal shielding loop 7 has previously been fixed, similar in height and thickness to those provided for layer type transformers. This part 6, 7 is fixed by snap on the transformer 1. Again, this is a part which, like the previous one, is expensive in terms of manufacturing cost, and which does not lend itself to automatic positioning on a production line for these cutting transformers. In addition, as in the previous case, the electromagnetic protection performance obtained is not absolutely perfect.

L'invention vise à remédier à ces inconvénients. Elle se rapporte à cet effet à un dispositif de blindage électromagnétique pour transformateur d'alimentation à découpage, destiné en particulier à équiper un téléviseur ou un moniteur, ce dispositif étant constitué par une seule pièce métallique en forme de cuvette ou coupelle, à fond plat et à bords dirigés vers le bas, s'adaptant au dessus du transformateur, afin d'assurer la protection électromagnétique de ce transformateur de telle sorte que cette pièce métallique puisse être aisément posée, et fixée par exemple par collage, sur ce noyau de ferrite. Ces bords sont choisis de largeur suffisamment faible pour ne pas affecter l'isolement galvanique procuré par le transformateur, mais toutefois assez importante pour d'une part permettre la mise en place aisée (par exemple par robot) de cette coupelle sur le sommet du transformateur et pour d'autre part assurer la protection électromagnétique souhaitée. Cette pièce est préférentiellement réalisée par emboutissage. Elle se pose sur le noyau de ferrite après dépose préalable de colle sur celui-ci (un ou deux points de colle par exemple), cette colle étant avantageusement la même que celle utilisée pour coller entre eux les éléments de ce noyau de ferrite. Ces opérations de collage et de mise en place s'effectuent aisément par une chaîne de robotisation automatique.The invention aims to remedy these drawbacks. To this end, it relates to an electromagnetic shielding device for a switching power supply transformer, intended in particular to equip a television set or a monitor, this device consisting of a single metal part in the form of a bowl or dish, with a flat bottom. and with edges directed downwards, adapting above the transformer, in order to ensure the electromagnetic protection of this transformer so that this metal part can be easily placed, and fixed for example by gluing, on this ferrite core . These edges are chosen to be of sufficiently small width so as not to affect the galvanic isolation provided by the transformer, but nevertheless large enough to allow on the one hand easy place (for example by robot) of this cup on the top of the transformer and on the other hand provide the desired electromagnetic protection. This part is preferably produced by stamping. It is placed on the ferrite core after prior deposit of glue on it (one or two points of glue for example), this glue is advantageously the same as that used to bond the elements of this ferrite core to each other. These bonding and positioning operations are easily carried out by an automatic robotization chain.

De toute façon, l'invention sera bien comprise, et ses avantages et autres caractéristiques ressortiront, lors de la description suivante d'un exemple non limitatif de réalisation, en référence à la figure 2 jointe, qui représente, en perspective et à l'échelle 1, ce dispositif de blindage et son mode de mise en place sur un transformateur d'alimentation à découpage.In any case, the invention will be well understood, and its advantages and other characteristics will emerge during the following description of a nonlimiting exemplary embodiment, with reference to FIG. 2 attached, which represents, in perspective and in scale 1, this shielding device and its mode of installation on a switching power supply transformer.

En se référant à cette figure 2, le transformateur d'alimentation à découpage 1 de la figure 1 y est représenté en perspective, avec son noyau de ferrite 2, ses galettes 3, ses fils de connexions 4, et ses broches d'entrée/sortie 5.Referring to this FIG. 2, the switching power supply transformer 1 of FIG. 1 is shown there in perspective, with its ferrite core 2, its wafers 3, its connection wires 4, and its input pins / exit 5.

Le dispositif de blindage électromagnétique est constitué par une cuvette, ou coupelle, 7 en cuivre, réalisée par emboutissage. Le fond plat 8 de cette coupelle est rectangulaire et a les mêmes dimensions extérieures que celles de la face rectangulaire supérieure 9 du noyau de ferrite 2. La coupelle 7 peut être en Al, laiton, etc...The electromagnetic shielding device is constituted by a bowl, or cup, 7 made of copper, produced by stamping. The flat bottom 8 of this cup is rectangular and has the same external dimensions as those of the upper rectangular face 9 of the ferrite core 2. The cup 7 can be made of Al, brass, etc.

Les bords 10 de la coupelle 7 sont évasés, avec une pente angulaire α par rapport à l'axe perpendiculaire au plan du fond 8 qui, étant de l'ordre de 15 à 20 degrés par exemple, est optimisée à la fois pour permettre la mise en place automatique aisée du chapeau 7 sur le dessus du transformateur 1 (comme indiqué en traits mixtes sur le dessin) avec les bords 10 orientés vers le bas, et pour assurer la protection électromagnétique souhaitée.The edges 10 of the cup 7 are flared, with an angular slope α relative to the axis perpendicular to the plane of the bottom 8 which, being of the order of 15 to 20 degrees for example, is optimized both to allow the easy automatic fitting of the cap 7 on the top of the transformer 1 (as indicated in dashed lines on the drawing) with the edges 10 facing downwards, and to ensure the desired electromagnetic protection.

La largeur L de ces bords 10 est choisie faible (de l'ordre de quelques millimètres par exemple) : elle doit être suffisante pour faciliter au maximum la mise en place de la coupelle 7 sur la face supérieure 9 du noyau 2, mais pas trop importante pour, tout en assurant la protection électromagnétique souhaitée, respecter les normes de protection galvanique du transformateur.The width L of these edges 10 is chosen to be small (of the order of a few millimeters for example): it must be sufficient to facilitate as much as possible the positioning of the cup 7 on the upper face 9 of the core 2, but not too much important for, while ensuring the electromagnetic protection desired, comply with the galvanic protection standards of the transformer.

La forme simple, sans découpes ou aspérités risquant de provoquer des accrochages de pièces l'une à l'autre, de la coupelle de blindage 7, et sa petite taille permettent son alimentation aisée dans une chaîne automatique robotisée, avec bol vibrant, sans modification sensible des lignes de fabrication.The simple shape, without cuts or roughness risking to catch pieces to each other, of the shielding cup 7, and its small size allow its easy feeding in a robotic automatic chain, with vibrating bowl, without modification. sensitive manufacturing lines.

Préalablement à la pose de la coupelle 7 par robot - suivant la flèche F et avec les bords 10 orientés vers le bas - sur le dessus 9 du transformateur 1, il est déposé, sur cette face supérieure 9 du noyau de ferrite 2, deux points de colle 11,12, cette colle étant avantageusement la même que celle utilisée pour assembler en 13 les deux moitiés du noyau de ferrite 2 (ce qui est très avantageux du point de vue approvisionnement en colle, pour lequel aucun surcoût n'est de ce fait entraîné en pratique).Prior to the installation of the cup 7 by robot - along the arrow F and with the edges 10 pointing downwards - on the top 9 of the transformer 1, two points are deposited on this upper face 9 of the ferrite core 2 of glue 11,12, this glue being advantageously the same as that used to assemble at 13 the two halves of the ferrite core 2 (which is very advantageous from the point of view of glue supply, for which no additional cost is of this fact trained in practice).

Les performances de protection électromagnétique des bobines déflectrices des téléviseurs et moniteurs sont, avec ce dispositif de blindage, pratiquement parfaites.The electromagnetic protection performances of the deflection coils of televisions and monitors are, with this shielding device, practically perfect.

Comme il va de soi, l'invention n'est pas limitée à l'exemple de réalisation qui vient d'être décrit, mais elle est, bien au contraire, susceptible d'être réalisée sous d'autres formes équivalentes.As is obvious, the invention is not limited to the embodiment which has just been described, but it is, on the contrary, capable of being produced in other equivalent forms.

Claims (6)

Dispositif de blindage électromagnétique pour transformateur d'alimentation à découpage, caractérisé en ce qu'il est constitué par une seule pièce métallique (7) à fond plat (8) et à bords dirigés vers le bas s'adaptant au dessus (9) du transformateur (1), afin d'assurer la protection électromagnétique de ce transformateur (1).Electromagnetic shielding device for switching power supply transformer, characterized in that it consists of a single metal part (7) with a flat bottom (8) and with edges directed downwards adapting to the top (9) of the transformer (1), to ensure the electromagnetic protection of this transformer (1). Dispositif de blindage électromagnétique selon la revendication 1 caractérisé en ce que cette pièce métallique (1) est réalisée par emboutissage.Electromagnetic shielding device according to claim 1 characterized in that this metal part (1) is produced by stamping. Blindage électromagnétique pour transformateur d'alimentation à découpage selon l'une des revendications 1 et 2, caractérisé en ce qu'il est apte à être fixé par collage (11, 12) sur la face supérieure (9) du noyau de ferrite (2) du transformateur (1), au moyen de la même colle qui est utilisée pour réaliser la solidarisation (13) des éléments constitutifs de ce noyau de ferrite (2).Electromagnetic shield for switching power supply transformer according to one of claims 1 and 2, characterized in that it is capable of being fixed by gluing (11, 12) on the upper face (9) of the ferrite core (2 ) of the transformer (1), by means of the same adhesive which is used to make the connection (13) of the constituent elements of this ferrite core (2). Transformateur d'alimentation pour téléviseur, caractérisé en ce qu'il comporte un dispositif de blindage électromagnétique selon l'une quelconque des revendications précédentes.Power transformer for television, characterized in that it comprises an electromagnetic shielding device according to any one of the preceding claims. Transformateur selon la revendication 4, caractérisé en ce qu'il est constitué d'un noyau de ferrite (2) et de galettes (3) guidant des fils (4) connectés aux broches de connexion 5.Transformer according to claim 4, characterized in that it consists of a ferrite core (2) and wafers (3) guiding wires (4) connected to the connection pins 5. Téléviseur comportant un transformateur d'alimentation à découpage, caractérisé en ce que ce transformateur comporte un dispositif de blindage électromagnétique selon l'une quelconque des revendications 1 à 3.Television set comprising a switching power supply transformer, characterized in that this transformer comprises an electromagnetic shielding device according to any one of Claims 1 to 3.
EP94400705A 1989-12-01 1990-11-28 Shielding device for a switching power supply transformer Expired - Lifetime EP0609155B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR8915884 1989-12-01
FR8915884A FR2655475B1 (en) 1989-12-01 1989-12-01 SHIELDING DEVICE FOR A CUT-OUT POWER TRANSFORMER.
EP90403369A EP0430802B1 (en) 1989-12-01 1990-11-28 Shielding device for a switching power supply transformer

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP90403369.3 Division 1990-11-28

Publications (3)

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EP0609155A2 true EP0609155A2 (en) 1994-08-03
EP0609155A3 EP0609155A3 (en) 1994-12-14
EP0609155B1 EP0609155B1 (en) 1996-10-30

Family

ID=9388042

Family Applications (2)

Application Number Title Priority Date Filing Date
EP90403369A Expired - Lifetime EP0430802B1 (en) 1989-12-01 1990-11-28 Shielding device for a switching power supply transformer
EP94400705A Expired - Lifetime EP0609155B1 (en) 1989-12-01 1990-11-28 Shielding device for a switching power supply transformer

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP90403369A Expired - Lifetime EP0430802B1 (en) 1989-12-01 1990-11-28 Shielding device for a switching power supply transformer

Country Status (5)

Country Link
EP (2) EP0430802B1 (en)
DE (2) DE69029045T2 (en)
ES (2) ES2088424T3 (en)
FR (1) FR2655475B1 (en)
SG (2) SG46473A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2756967A1 (en) * 1996-12-09 1998-06-12 Thomson Television Components TRANSFORMER FOR HIGH-CUT FREQUENCY POWER SUPPLY

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3311391B2 (en) 1991-09-13 2002-08-05 ヴィエルティー コーポレーション Leakage inductance reducing transformer, high frequency circuit and power converter using the same, and method of reducing leakage inductance in transformer
DE69631462D1 (en) * 1995-11-27 2004-03-11 Vlt Corp Plating permeable cores

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1069711B (en) * 1959-11-26
EP0081111A1 (en) * 1981-12-04 1983-06-15 Licentia Patent-Verwaltungs-GmbH Transformer, particularly for a switching mode power supply circuit in a television receiver
EP0131700A2 (en) * 1983-05-09 1985-01-23 Zanussi Elettromeccanica S.p.A. Switch mode transformer having a ferrite core

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH607264A5 (en) * 1975-05-23 1978-11-30 Landis & Gyr Ag Instrument transformer with earthed screen between windings
DE2931382A1 (en) * 1979-08-02 1981-02-26 Bosch Gmbh Robert SHORT RING SENSOR
DD200830A1 (en) * 1981-09-25 1983-06-15 Martin Dietrich HOCHSPANNUNGSABSCHIRMELEKTRODE
JPS61137309A (en) * 1984-12-08 1986-06-25 Nissin Electric Co Ltd Gas insulated potential transformer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1069711B (en) * 1959-11-26
EP0081111A1 (en) * 1981-12-04 1983-06-15 Licentia Patent-Verwaltungs-GmbH Transformer, particularly for a switching mode power supply circuit in a television receiver
EP0131700A2 (en) * 1983-05-09 1985-01-23 Zanussi Elettromeccanica S.p.A. Switch mode transformer having a ferrite core

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2756967A1 (en) * 1996-12-09 1998-06-12 Thomson Television Components TRANSFORMER FOR HIGH-CUT FREQUENCY POWER SUPPLY
EP0848396A1 (en) * 1996-12-09 1998-06-17 Thomson Television Components France Transformer for switched-mode power supply
US5982263A (en) * 1996-12-09 1999-11-09 Thomson Television Components France Higher frequency switch mode transformer

Also Published As

Publication number Publication date
EP0430802B1 (en) 1996-05-29
FR2655475A1 (en) 1991-06-07
SG46710A1 (en) 1998-02-20
ES2088424T3 (en) 1996-08-16
DE69029045D1 (en) 1996-12-05
SG46473A1 (en) 1998-02-20
DE69027185D1 (en) 1996-07-04
DE69029045T2 (en) 1997-09-25
FR2655475B1 (en) 1992-02-21
ES2097613T3 (en) 1997-04-01
EP0609155B1 (en) 1996-10-30
EP0430802A1 (en) 1991-06-05
DE69027185T2 (en) 1996-11-07
EP0609155A3 (en) 1994-12-14

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