EP3792941B1 - Component forming at least one inductance for an electrical circuit - Google Patents

Description

The present invention relates to a component forming at least one inductance for an electrical circuit. This inductance is for example a coil or all or part of a transformer.

The electrical circuit is for example an on-board network of a motor vehicle, for example a 12 V network, a 48 V network, or else an on-board network with different voltages, for example a 12 V voltage part and a voltage 48 V. The electrical circuit may still have a higher voltage, in particular a voltage with a value greater than 300 V, for example when it is used within a purely electrically powered vehicle.

It is known to produce a smoothing coil by causing one or more electrically conductive tracks of a printed circuit board and a structure made of a magnetically conductive material to cooperate. These electrically conductive tracks are suitable to avoid losses at high frequencies but are likely to cause continuous losses.

It is also known to arrange in a structure made of a magnetically conductive material a copper bus bar to produce a smoothing coil. The presence of such a bus bar is likely to cause losses at high frequencies but is adapted to avoid continuous losses.

We also know of requests FROM 10 2016 219 790 and JP 2004-303857 transformers whose primary is formed by the electrically conductive tracks of a printed circuit and whose secondary is formed by a bus bar, these electrically conductive tracks and this bus bar not being electrically connected to one another.

There is a need to produce an inductance by causing an electrically conductive element to cooperate with a structure made of a magnetically conductive material with reduced losses both continuously and at high frequencies, in a simple and robust manner, and easily achievable.

• au moins une structure en un matériau magnétiquement conducteur,
• une portion de carte de circuit imprimé assemblée avec la structure et contenant au moins une piste électriquement conductrice, et
• au moins une barre-bus fixée sur la portion de carte de circuit imprimé,

la barre-bus et la piste électriquement conductrice de la portion de carte de circuit imprimé étant disposées l'une par rapport à l'autre et directement connectées de manière à former un élément électriquement conducteur coopérant avec la structure en matériau magnétiquement conducteur pour former l'inductance,
la barre-bus étant formée par au moins deux tronçons successivement empruntés par du courant circulant dans cette barre-bus.The object of the invention is to meet this need and it achieves this, according to one of its aspects, with the aid of a component forming at least one inductance, the component comprising:

• at least one structure made of a magnetically conductive material,
• a printed circuit board portion assembled with the structure and containing at least one electrically conductive track, and
• at least one bus bar fixed to the printed circuit board portion,

the bus bar and the electrically conductive track of the printed circuit board portion being arranged relative to each other and directly connected so as to form an electrically conductive element cooperating with the structure made of magnetically conductive material to form the 'inductance,
the bus bar being formed by at least two sections successively taken by current flowing in this bus bar.

The bus bar and the electrically conductive track of the printed circuit board portion can be electrically connected to one another, for example via one or more attachments, in particular solder attachments. These fasteners form an electrical contact. This electrical connection can thus be described as direct, in particular not involving an intermediate magnetic circuit.

• la fixation de la barre-bus à la piste électriquement conductrice de la portion de carte de circuit imprimé entre lesdits tronçons et/ou
• de la piste électriquement conductrice de la portion de carte de circuit imprimé entre lesdits tronçons.

These fasteners may also allow current flowing in one section of the busbar to flow into the next section. In other words, the passage of the current between two successive sections of the bus bar then implies the borrowing of:

• attaching the bus bar to the electrically conductive track of the printed circuit board portion between said sections and/or
• of the electrically conductive track of the printed circuit board portion between said sections.

The combination of the busbar and the electrically conductive trace of the printed circuit board portion provides an electrically conductive element having the advantages provided by the busbar in terms of reduced continuous losses and the advantages provided by the electrically conductive trace of the printed circuit board portion in terms of reduced losses at high frequencies.

Furthermore, the presence of the bus bar, and in particular its attachment to the electrically conductive track of the printed circuit board portion, can make it possible to improve the thermal conductivity in the electrically conductive track, thus making it possible to avoid the occurrence of excessive temperatures in the printed circuit board portion. This improves the robustness and efficiency of the printed circuit board portion.

Finally, the production of the bus bar in several sections makes it possible to guarantee good flatness for fixing, in particular the soldering, of the bus bar on the printed circuit board portion. Each section may have a flatness of less than 0.1 mm. The division of the busbar into sections is in particular suitable for flattened busbar shapes, the latter having for example a ribbon shape characterized by a significant length compared to its width, itself greater than its thickness.

The bus bar and the electrically conductive track can be arranged in parallel, electrically speaking. Such a parallel assembly can make it possible to reduce the current density in the electrically conductive track(s) of the printed circuit board portion.

The bus bar and the electrically conductive track can be superimposed along a direction perpendicular to the plane of extension of the printed circuit board portion. Other said, the electrically conductive track and the busbar can be arranged one above the other, having in particular the same shape.

The bus bar is for example fixed, in particular brazed, on the electrically conductive track of the printed circuit board portion. In the case where several soldering attachments exist, the passage of the current between two successive sections can take place via the solder paste interposed between said sections and/or via the area of the electrically conductive track interposed between these sections.

The printed circuit board portion comprises for example several electrically conductive tracks superimposed along a direction perpendicular to the extension plane of this printed circuit board portion, and the busbar is superimposed with these electrically conductive tracks along said direction.

• une première piste électriquement conductrice définissant une partie d'une première surface extérieure de la portion de carte de circuit imprimé,
• une deuxième piste électriquement conductrice définissant une partie d'une deuxième surface extérieure de la portion de carte de circuit imprimé, la première et la deuxième surface étant opposées, et
• au moins une troisième piste électriquement conductrice, disposée à l'intérieur de la portion de carte de circuit imprimé.

The printed circuit board portion comprises for example:

• a first electrically conductive track defining a part of a first exterior surface of the printed circuit board portion,
• a second electrically conductive track defining a portion of a second exterior surface of the printed circuit board portion, the first and second surfaces being opposed, and
• at least one third electrically conductive track, arranged inside the printed circuit board portion.

The bus bar is for example fixed on the second surface of the printed circuit board portion and has in particular several fixings forming electrical contact with the second electrically conductive track. The bus bar can thus be mounted in parallel with all the electrically conductive tracks of the printed circuit board portion, additional electrical connections existing between the second electrically conductive track and this bus bar due to the aforementioned electrical contact points.

Several third electrically conductive tracks can be present, for example two, three, four or more.

In a specific example, the printed circuit board portion comprises six stacked electrically conductive tracks, namely a first track, a second track and four third tracks.

The structure made of magnetically conductive material may comprise: a base, a cover, and a junction wall between the base and the cover, the base being arranged on a first side of the printed circuit board portion and the cover being arranged on a second side of the printed circuit board portion. The structure made of magnetically conductive material forms, for example, a casing. Openings can be provided in the portion printed circuit board to allow the passage of elements of the junction wall of the structure made of magnetically conductive material. The base and the cover can belong to separate parts.

The first side of the printed circuit board portion is bounded by the first surface thereof while the second side of the printed circuit board portion is bounded by the second surface thereof.

Several inductors are for example formed by cooperation between the electrically conductive element and the structure made of magnetically conductive material. These different inductors are for example made according to the teaching of the patent application filed by the Applicant in France on June 8, 2018 under the filing number 18 54988 and corresponding to the application WO 2019/233880 . The content of this French patent application is incorporated by reference into the present application, in particular in that it teaches circulating the magnetic flux associated with each inductance in a first leg of the structure made of magnetically conductive material, this first leg being devoid of an air gap, and in a second leg of this structure, this second leg being dedicated to this inductance and involving the crossing of an air gap.

The component may comprise a single structure made of magnetically conductive material with which the electrically conductive element cooperates to form the inductance(s).

As a variant, the component may comprise a plurality of structures made of magnetically conductive material, distinct from each other, each of these structures cooperating with the electrically conductive element so as to form, for each cooperation, one or more inductances. Each of these structures made of magnetically conductive material is for example carried by the printed circuit board portion.

Where appropriate, the component may comprise one or more capacitors, the latter being in particular carried by the portion of the printed circuit board. A capacitor is for example associated with an inductance so as to form an LC filter for electromagnetic interference.

In all of the above, the bus bar and the electrically conductive track can each define several successive turns around an axis perpendicular to the plane of extension of the printed circuit board portion.

When the structure made of magnetically conductive material comprises a junction wall between the base and the cover, the base being placed on a first side of the printed circuit board portion and the cover being placed on a second side of the printed circuit board, the junction wall may include at least one leg extending seamlessly between the base and the cover, and the bus bar and the electrically conductive track may each define several successive turns around this leg. For example, one or more current smoothing coils are thus formed.

In this case, the junction wall may further comprise at least one other leg, or even two other legs extending between the base and the cover so as to define at least one air gap. When the cooperation between the structure made of magnetically conductive material and the electrically conductive element defines two inductors, two other legs can be provided, the leg extending without discontinuity being placed between these two other legs.

• un premier flux magnétique associé à une première inductance définie par le composant peut circuler entre la base et le couvercle de la structure : à travers la jambe sans discontinuité et à travers une des autres jambes qui est dédiée à cette première inductance, et
• un deuxième flux magnétique associé à une deuxième inductance définie par le composant peut circuler entre la base et le couvercle de la structure : à travers la jambe sans discontinuité et à travers une autre des autres jambes, qui est dédiée à cette deuxième inductance.

Still in this case:

• a first magnetic flux associated with a first inductance defined by the component can circulate between the base and the cover of the structure: through the leg without discontinuity and through one of the other legs which is dedicated to this first inductance, and
• a second magnetic flux associated with a second inductance defined by the component can circulate between the base and the cover of the structure: through the leg without discontinuity and through another of the other legs, which is dedicated to this second inductance.

Whether the junction wall comprises one or more legs, this or these legs can be made in one piece with the base, the lid then having the shape of a plate without a leg.

In all of the above, the busbar can have the form of a ribbon. The bus bar is for example flattened, that is to say it has in the extension plane of the printed circuit board a width much greater than the dimension of this bus bar perpendicular to this plane of extension, also called "thickness", having for example a width at least three or four times greater than this thickness. The busbar has for example a length greater than 5 cm, a thickness of the order of 1 mm and a width of the order of 10 mm.

The busbar can have a length/width ratio between 5 and 10 and a width/thickness ratio between 5 and 10.

The inductance can form a smoothing coil, an EMC filtering coil or a differential filtering coil, or a coupled inductance coil, or even all or part of a transformer.

In one example, certain electrically conductive tracks of the printed circuit board portion and the bus bar form the secondary, respectively primary, of the transformer while other electrically conductive tracks of this same printed circuit board portion, stacked with the aforementioned tracks form the primary, respectively secondary, of this transformer.

As a variant, the electrically conductive tracks of the printed circuit board portion and the busbar form only part of the transformer, for example only the primary or the secondary of this transformer.

In all of the above, one end of the bus bar can be connected to the corresponding end of the electrically conductive track, these ends connected to each other then being connected to a current measurement shunt, this shunt being in particular carried by the printed circuit board portion. The shunt can form an electrical connection to another component of the electrical circuit, for example controllable electronic switches, such as field-effect or bipolar transistors. This or these other electronic components may or may not be carried by the printed circuit board, not necessarily by said portion thereof.

The shunt forming this connection can span the electrically conductive track of the printed circuit board portion, this spanned electrically conductive track being for example the first electrically conductive track or the second electrically conductive track when the printed circuit board portion comprises several tracks electrically conductive.

The shunt can be mounted on the first surface of the printed circuit board portion while the bus bar, and the optional capacitor(s), are for example mounted on the second surface of this printed circuit board portion.

Several busbars can be fixed on the printed circuit board portion, so that the electrically conductive element according to the invention can be formed by several electrically conductive tracks of the printed circuit board portion and by several busbars .

In all of the above, the component may comprise only a single printed circuit board portion, and not several printed circuit board portions, for example offset with respect to each other.

The component comprises for example successively, in a direction perpendicular to the plane of extension of the printed circuit board portion: the base of the structure made of magnetically conductive material, the printed circuit board portion, the bus bar and the the structure in magnetically conductive material. The component is for example devoid of any other bus bar and/or any other printed circuit board portion.

In all of the foregoing, the busbar may consist of a number of sections greater than 2, for example between 2 and 1000, in particular between 2 and 100, for example between 10 and 100.

Each section of the busbar can have the same shape. The use of the same form can make it possible to simplify the manufacturing process of the busbar.

As a variant, in all of the above, the sections of the busbar can have different shapes. The use of different shapes makes it possible to envisage a more complex geometry for the busbar, for example in the shape of an S.

Each section of the bus bar can extend between a first face and a second face, the first face of a section being able to be positioned facing the second face of another section and the second face of the section being able to be positioned facing the first face of yet another section to ensure the passage of the current from one section to the other, and one and/or the other of the first and of the second face can have as normal the direction of propagation of the current in said section. Each end face of the section, that is to say the first face and the second face of this section which define for said section according to the direction of the current the entry face or the exit face of the current in the section , can thus be perpendicular to the direction of propagation of the current. Each section can, in top view, have the shape of a rectangle. A busbar with rectangular sections, and in particular of the same shape, can be simple to manufacture.

As a variant, each section of the bus bar can extend between a first face and a second face, the first face of a section being capable of being positioned facing the second face of another section and the second face of the section being capable of being positioned facing the first face of yet another section to ensure the passage of the current from one section to the other, and one and/or the other of the first and the second face may not have as normal the direction of propagation of the current in said section. Each end face of the section, that is to say the first face and the second face of this section which define for said section according to the direction of the current respectively the entry face and/or the exit face of the current in the section can then extend obliquely in a way that is not perpendicular to the direction of propagation of the current. Each section can, in top view, have the shape of a parallelogram. Section end faces not perpendicular to the current propagation direction make it possible to reduce the current density at the interconnection between the sections and therefore to avoid the appearance of hot spots.

In all of the foregoing, whether or not the first and/or the second face have the direction of propagation of the current in the section as normal, this first, respectively second, face may be flat. Each section can have its first face parallel to its second face, when these two faces are flat.

As a variant, whether or not the first and/or the second face have the direction of propagation of the current in the section as normal, this first, respectively second, face may be non-planar. It is for example a curved face, in particular cylindrical, or a face formed by several secant planes, for example by the union of two secant planes.

In all of the above, each section may have a second face of the same shape, or of a different shape, than its first face.

In all of the above, each first face of a section can be placed opposite a second face of another section which has the same shape, which promotes the transmission of current from one section to the other.

In all of the above, each section may or may not have a polygonal shape.

In all of the above, the sections can be arranged so that the bus bar extends straight along its entire length. All the sections preferably have the same shape in the case of a bus bar extending straight over its entire length.

As a variant, in all of the above, the sections can be arranged so that the bus bar does not extend straight along its entire length. Such a busbar may be better suited to a more constrained environment in terms of space. Different shapes for the sections are then preferably provided. Angles between 0 and 90° can be set between consecutive sections of the busbar.

The sections of the busbar can be arranged one after the other, without branching. This arrangement without branching can be obtained whether or not the sections have the same shape.

As a variant, the sections of the busbar can be arranged so as to define at least one branch. One of the sections then has a first face and several second faces, in particular two or three second faces, so as to define the branch. If necessary, the section defining the branch can have a shape different from those of sections not defining a branch. The section defining the branch can have its second faces of the same shape and this same shape can differ from that of its first face, or even be identical to the shape of the first face. As a variant, all the sections can have the same shape, despite the presence of the branch. In the latter case, the section defining the branch has only a second face.

The branch can define two branches, three branches, or more.

Whether the busbar only comprises sections of the same shape or whether it comprises sections of different shapes, all the sections having the same shape can be arranged in the same way along the length of the busbar.

As a variant, whether the busbar only comprises sections of the same shape or whether it comprises sections of different shapes, sections having the same shape can be arranged differently, in particular inverted, along the length of the busbar. bus.

Another subject of the invention, according to another of its aspects, is a DC/DC voltage converter, in particular a 12 V/48 V DC/DC voltage converter, comprising a component as defined above.

The invention can, more generally, apply to any static converter, thus including DC/AC converters, also called “inverters/rectifiers”.

The invention can also be applied for a charging circuit inductance of an electrical energy storage unit of a vehicle with hybrid or purely electric propulsion. This electrical energy storage unit has for example a nominal voltage of 48 V or more, for example a nominal voltage whose value is greater than 300 V.

• assembler une structure en matériau magnétiquement conducteur avec une portion de carte de circuit imprimé, cette portion de circuit imprimé comprenant au moins une piste électriquement conductrice,
• fixer sur la portion de carte de circuit imprimé au moins une barre-bus, après avoir disposé cette barre-bus par rapport à la piste électriquement conductrice de manière à former un élément électriquement conducteur coopérant avec la structure en matériau magnétiquement conducteur pour former l'inductance, la barre-bus étant formée par au moins deux tronçons successivement empruntés par du courant circulant dans cette barre-bus.

Another subject of the invention, according to another of its aspects, is a method for producing at least one inductance, comprising the steps consisting in:

• assembling a structure made of magnetically conductive material with a printed circuit board portion, this printed circuit portion comprising at least one electrically conductive track,
• fixing on the printed circuit board portion at least one busbar, after having disposed this busbar relative to the electrically conductive track so as to form an electrically conductive element cooperating with the structure made of magnetically conductive material to form the inductor, the bus bar being formed by at least two sections successively borrowed by the current flowing in this bus bar.

All or some of the preceding characteristics still apply to the process which has just been mentioned.

The aforementioned assembly and fixing steps can occur successively or simultaneously. “Simultaneously” means that the assembly is terminated at the same time as the fixing step.

The fixing of the bus bar on the portion of the printed circuit board is carried out for example by soldering, in particular in a reflow oven. Each section of the bus bar is for example soldered to the electrically conductive track of the printed circuit board portion. When the printed circuit board portion comprises several electrically conductive tracks, the bus bar is for example soldered to one of the electrically conductive tracks present on an end surface of this printed circuit board portion, namely the first electrically conductive track or the aforementioned second electrically conductive track.

• disposer une première partie de la structure en matériau magnétiquement conducteur sur la première surface de la portion de carte de circuit imprimé, de la colle étant par exemple interposée entre cette première surface et cette première partie de la structure,
• disposer le cas échéant d'autres composants tels qu'un shunt sur cette première surface, de la pâte à braser étant alors interposée entre cette première surface et ce ou ces composants,
• disposer l'ensemble obtenu dans un four de polymérisation en l'absence de pâte à braser, ou dans un four de refusion lorsque de la pâte à braser est également présente,
• retourner ensuite la portion de carte de circuit imprimé et disposer la deuxième partie de la structure en matériau magnétiquement conducteur sur la deuxième surface de la portion de carte de circuit imprimé, de la colle étant par exemple interposée entre cette deuxième surface et cette deuxième partie de la structure,
• disposer la barre-bus sur cette deuxième surface de la portion de carte de circuit imprimé, et le cas échéant un ou plusieurs autres composants, de la pâte à braser pouvant alors être interposée entre cette deuxième surface et la barre-bus, la pâte à braser étant notamment présente entre les tronçons successifs de la barre-bus, et
• disposer l'ensemble obtenu dans un four de refusion.

During the process, you can:

• arranging a first part of the structure made of magnetically conductive material on the first surface of the printed circuit board portion, glue being for example interposed between this first surface and this first part of the structure,
• arranging, where appropriate, other components such as a shunt on this first surface, solder paste then being interposed between this first surface and this or these components,
• place the assembly obtained in a polymerization oven in the absence of solder paste, or in a reflow oven when solder paste is also present,
• then turn over the printed circuit board portion and arrange the second part of the structure made of magnetically conductive material on the second surface of the printed circuit board portion, glue being for example interposed between this second surface and this second part of the structure,
• arrange the bus bar on this second surface of the printed circuit board portion, and if necessary one or more other components, solder paste can then be interposed between this second surface and the bus bar, the solder paste solder being in particular present between the successive sections of the bus bar, and
• place the assembly obtained in a reflow oven.

In the above, the solder paste is for example deposited by screen printing.

• la figure 1 est une vue en éclaté d'un premier composant auquel peut s'appliquer l'invention,
• la figure 2 représente le premier composant de la figure 1 à l'état assemblé
• la figure 3 est une vue similaire à la figure 2 d'un deuxième composant auquel peut s'appliquer l'invention,
• la figure 4 représente un premier exemple de barre-bus en tronçons selon l'invention,
• la figure 5 représente un deuxième exemple de barre-bus en tronçons selon l'invention,
• la figure 6 représente un troisième exemple de barre-bus en tronçons selon l'invention,
• la figure 7 représente un quatrième exemple de barre-bus en tronçons selon l'invention,
• la figure 8 représente un cinquième exemple de barre-bus en tronçons selon l'invention,
• la figure 9 représente un sixième exemple de barre-bus en tronçons selon l'invention, et
• la figure 10 représente un septième exemple de barre-bus en tronçons selon l'invention.

The invention can be better understood on reading the following description of non-limiting examples of its implementation and on examining the appended drawing in which:

• the figure 1 is an exploded view of a first component to which the invention can be applied,
• the picture 2 represents the first component of the figure 1 in assembled state
• the picture 3 is a view similar to the figure 2 of a second component to which the invention can be applied,
• the figure 4 represents a first example of a bus bar in sections according to the invention,
• the figure 5 represents a second example of a bus bar in sections according to the invention,
• the figure 6 represents a third example of a busbar in sections according to the invention,
• the figure 7 represents a fourth example of a bus bar in sections according to the invention,
• the figure 8 represents a fifth example of a busbar in sections according to the invention,
• the figure 9 represents a sixth example of a busbar in sections according to the invention, and
• the figure 10 represents a seventh example of a bus bar in sections according to the invention.

We represented on the figure 1 in exploded view a first component 1 to which the invention can be applied. This first component 1 here forms a single inductance for a motor vehicle electrical circuit. This electrical circuit is for example the on-board network of this vehicle.

In the example which will be described, the electrical circuit has on the one hand a 12 V part, on the other hand a 48 V part, and a DC/DC voltage converter 12 V/48 V to connect these two circuit parts. The inductance obtained can be a current smoothing coil, an EMC filtering coil, a differential filtering coil, or even all or part of a transformer, as will be seen later.

On the figure 1 , it is noted that the first component 1 comprises a printed circuit board portion 2, which here comprises several electrically conductive tracks 3. Each of these tracks 3 is here made of copper. In the example considered, the electrically conductive tracks 3 are stacked together according to the thickness of the portion 2 of the printed circuit board.

A first electrically conductive track 3 defines a part of a first outer surface 2a of the printed circuit board portion 2, a second electrically conductive track 3 defines a part of a second outer surface 2b of the printed circuit board portion 2, the first and the second surface being opposed. Several third electrically conductive tracks 3 are arranged inside the portion 2 of the printed circuit board.

The first component 1 further comprises a structure 4 made of a magnetically conductive material, and a busbar 6.

We see on the figure 1 that the structure 4 made of magnetically conductive material comprises: a base 7, a cover 8 and a junction wall 10 between the base 7 and the cover 8. As can be seen in the figure 1 , the base 7 is arranged on a first side of the printed circuit board portion 2, and the cover 8 is arranged on a second side of this printed circuit board portion 2. The junction wall 10 extends through openings 9 formed in the portion 2 of the printed circuit board.

The junction wall 10 here comprises three legs: an internal leg 11 with an air gap and two external legs 12 without an air gap which frame this internal leg 11. It can be seen that each electrically conductive track 3 is wound around the internal leg 11, two turns around this internal leg 11 between two running ends respectively referenced by 13 and 14. This winding takes place around an axis perpendicular to the plane of extension of the portion 2 of the printed circuit board.

• une première partie de la structure qui comprend la base 7 et qui est disposée du premier côté de la portion de carte de circuit imprimé, et
• une deuxième partie de la structure qui comprend le couvercle 8 et qui est disposée du deuxième côté de la portion de carte de circuit imprimé.

The structure 4 is here cut in two, so that we observe before assembly:

• a first part of the structure which comprises the base 7 and which is arranged on the first side of the printed circuit board portion, and
• a second part of the structure which includes the cover 8 and which is arranged on the second side of the printed circuit board portion.

The busbar 6 is in the example considered made of copper and it is formed by several sections 30, as will be seen later. Busbar 6 also defines two turns around inner leg 11 around the same axis as the electrically conductive track. The bus bar 6 extends between two ends respectively referenced by 16 and 17. The bus bar can have one or more retaining lugs 18, the presence of these retaining lugs 18 being purely optional.

We see on the figure 1 that a shunt 30 is carried by the printed circuit board portion 2, this shunt 30 being mounted on the first surface 2a of the printed circuit board portion 2 while the bus bar 6 is mounted on the second surface 2b of this portion 2 of the printed circuit board. The end 17 of the bus bar 6 and each end 14 of an electrically conductive track 3 are connected together and this common end is connected to the shunt 30 to allow electrical connection to other components carried by the circuit board printed. The shunt 30 spans, for example, the first electrically conductive track 3 of the printed circuit board portion.

We see on the figure 1 that the electrically conductive tracks 3 and the busbar 6 are superimposed, having the same shape. End 16 of this busbar is electrically connected to each end 13 of electrically conductive tracks 3 and end 17 of this busbar is electrically connected to each end 14 of these electrically conductive tracks. These electrically conductive tracks 3 and the busbar 6 are thus mounted in parallel in the example considered. As will be seen later, the situation is particular between the busbar 6 and the second electrically conductive track 3, the latter still having several intermediate electrical connections between them, between their ends.

The busbar 6 is positioned relative to the electrically conductive tracks 3 so that the electrically conductive tracks 3 and the busbar 6 together define an electrically conductive element whose cooperation with the structure 4 here defines an inductor.

The bus bar 6 is in the example considered fixed by soldering on the second surface 2b of the portion 2 of the printed circuit board 2, as will now be described. This busbar 6 then has several points of electrical contact, also called "fasteners", with the second electrically conductive track 3 opposite which it is located, thus defining additional electrical connections with this track. These fasteners are in the example considered arranged between the successive sections of the bus bar 6.

• on dispose la première partie de la structure 4 en matériau magnétiquement conducteur sur la première surface 2a de la portion de carte de circuit imprimé, de la colle 21 se présentant sous forme de bandes étant ici interposée entre cette première surface 2a et cette première partie de la structure 4,
• on dispose le shunt 30 sur cette première surface 2a, de la pâte à braser étant alors interposée entre cette première surface 2a et ce shunt 30,
• on dispose l'ensemble obtenu dans un four de refusion,
• on retourne après cuisson la portion 2 de carte de circuit imprimé et on dispose la deuxième partie de la structure 4 en matériau magnétiquement conducteur sur la deuxième surface 2b de la portion 2 de carte de circuit imprimé, des bandes de colle 21 étant interposées entre cette deuxième surface et cette deuxième partie de la structure,
• on dispose la barre-bus 6 sur cette deuxième surface 2b de la portion 2 de carte de circuit, de la pâte à braser étant alors interposée sous forme de plots 20 entre cette deuxième surface 2b et la barre-bus 6, et
• on dispose l'ensemble obtenu dans un four de refusion.

To make component 1, proceed as follows, for example:

• the first part of the structure 4 of magnetically conductive material is placed on the first surface 2a of the printed circuit board portion, glue 21 in the form of strips being here interposed between this first surface 2a and this first part of structure 4,
• the shunt 30 is placed on this first surface 2a, solder paste then being interposed between this first surface 2a and this shunt 30,
• the assembly obtained is placed in a reflow oven,
• the portion 2 of the printed circuit board is turned over after baking and the second part of the structure 4 made of magnetically conductive material is placed on the second surface 2b of the portion 2 of the printed circuit board, strips of glue 21 being interposed between this second surface and this second part of the structure,
• the bus bar 6 is placed on this second surface 2b of the circuit board portion 2, solder paste then being interposed in the form of pads 20 between this second surface 2b and the bus bar 6, and
• the assembly obtained is placed in a reflow oven.

The solder paste can be deposited by screen printing. The adhesive can be cured in the oven or during pre-treatment.

We thus obtain the first component 1 according to the figure 2 . This first component 1 forms for example a current smoothing coil which can be used in the aforementioned electric circuit.

We will now describe with reference to the picture 3 another example to which the invention applies. According to this other example, the second component 1 comprises two structures 4 made of magnetically conductive material. Each of these structures 4 is assembled on the printed circuit board portion 2, each of these structures possibly extending on either side of this printed circuit board portion 2 or not.

Similar to what has been described with reference to figures 1 and 2 , the busbar 6 is fixed on the portion 2 of the printed circuit board and it is arranged with respect to the electrically conductive tracks of this portion of the board which are not visible on this picture 3 , so as to form an electrically conductive element. This electrically conductive element cooperates with each structure 4 so as to form, for each cooperation, an inductance which here is an EMC filtering coil. In the example of the picture 3 , these two EMC filter coils are connected in series and the printed circuit board portion 2 carries two capacitors 25. Each of these capacitors 25 is associated with one of the filter coils so as to form with this coil an LC filter.

We will maintain with reference to figures 4 to 10 various examples of bus bar 6 in sections according to the invention. The bus bar here has the form of a ribbon, having for example a length greater than 5 cm, a width of the order of 1 cm, and a thickness of the order of 1 mm.

Each section 30 extends between a first face 31 which is intended to come opposite another section 30 of the bus bar, and a second face 32 which is intended to come opposite another section of the bus bar .

According to the first and second examples, which will be described with reference to the figure 4 and 5 , each section 30 constituting the busbar has the same shape. Each section thus has, in top view, the shape of a quadrilateral.

In the example of the figure 4 , each section 30 has the shape of a rectangle, and each of the first face 31 and of the second face 32 has as its normal the direction D of propagation of the current in this section 30. The busbar 6 extends in the example of the figure 4 straight along its entire length.

In the example of the figure 5 , each section has the shape of a parallelogram, and each of the first face 31 and of the second face 32 does not have the direction D of propagation of the current in this section 30 as its normal. figure 5 that the first face 31 and the second face 32 are here parallel and extend obliquely with respect to the direction D. The different sections 30 are, in the example of the figure 5 , arranged so that the busbar does not extend straight. This bus bar 6 can thus define several bends.

The example of the figure 6 differs from the previous examples in that the busbar comprises sections of different shape. Certain sections 30 always have a quadrilateral shape, for example a parallelogram, while other sections have another shape, for example triangular or polygonal, which is other than a triangle or a quadrilateral, for example a pentagon. It is thus possible to further complicate the overall geometry of the bus bar 6.

In the example described with reference to the figure 7 , the sections 30 are all of the same shape but they have a different geometry between their first face 31 and their second face 32. It can be seen that none of the latter is flat. On the contrary, these faces are cylindrical. The first face 31 of a section 30 here defines a convex surface while the second face 32 of this section defines a concave surface. The shape of the first face 31 is here the same as that of the second face 32. These shapes can define a kind of pivot connection between two consecutive sections 30, allowing a large choice of angle of inclination between these two sections.

The example of the figure 8 provides another example of a busbar 6 extending non-straight. In this example, sections 30 of different shapes exist, some sections 30a having the same shape as in the example of the figure 7 and other sections 30b having a different shape. It can be seen, for example, that a section 30b has a first face 31 and a second face 32 of cylindrical shape, and that the sections 30a directly adjacent to this section 30b are positioned inversely with respect to each other. Indeed, the section 30a downstream of the section 30b in the direction of propagation S of the current has a first face 31 which defines a convex surface and a second face 32 which defines a concave surface, while the section 30a downstream of the section 30b in the direction of current propagation has a first face which defines a concave surface and a second face 32 which defines a convex surface.

In all the examples which have just been described, the sections 30 are arranged one after the other, so as not to define a branch.

However, the invention is not limited thereto. In the example of the figure 8 for example, the cylindrical surfaces of the section 30b which appear free could be associated with a section 30a so as to define another branch for the current.

The examples of the figure 9 and some figure 10 show busbars 6 with sections arranged so as to define a branch.

In the example of the figure 9 , all sections 30 have the same shape with first and second curved faces. Each first face 31 defines a concave surface while each second face 32 defines a convex surface. It can be seen that two sections 30 are inclined with respect to the immediately preceding section 30 so that the convex surface defined by the second face 32 of this immediately preceding section cooperates with the first face 31 of two separate sections. A branch is created here without the need to have a specific shape of section to make the branch.

In the example of the figure 10 , the creation of a branch with three branches in the busbar is obtained by using sections of different shape. The bus bar 6 comprises sections 30a of the same shape, having first face 31 and second face 32 of the same shape, here in a broken line. A section 30b here has a different shape, having a first face 31 in the shape of a broken line and three second faces 32, all in the shape of a broken line. We see on the figure 10 that the sections 30a upstream of the section 30b in the direction of propagation S of the current in the bus bar 6 are positioned in reverse with respect to the sections 30a which are downstream of the section 30b. Indeed, while the second face 32 and the first face of a section 30a downstream of the section 30b respectively define a convex surface and a concave surface, the second face 32 and the first face 31 of a section 30a downstream of the section 30b respectively define a concave surface and a convex surface.

The invention is not limited to the examples which have just been described.

The invention can for example be used to produce all or part of a transformer. For example, a high-current secondary winding of a transformer is produced with the combination of a bus bar and one or more electrically conductive tracks of a portion of a printed circuit board according to the invention, while the lower current primary winding of this transformer is produced using other electrically conductive tracks, the latter belonging or not to this same portion of the printed circuit board and this primary winding being produced without adding a bar -bus.

In variants not described, several busbars 6 can be fixed on the portion 2 of the printed circuit board, these busbars 6 being stacked on top of each other, each time with the interposition of an electrical insulator. The electrically conductive element is then formed by: the electrically conductive tracks of the printed circuit board portion 2, and the stacked busbars 6.

Claims (13)

1. Component (1) forming at least one inductor, the component comprising:

   - at least one structure (4) made of a magnetically conductive material;

   - a portion of printed circuit board (2) assembled with the structure (4), and containing at least one electrically conductive track (3); and

   - at least one bus bar (6) secured on the portion of printed circuit board (2), the bus bar (6) and the electrically conductive track (3) of the portion of printed circuit board (2) being placed relative to one another and directly connected, such as to form an electrically conductive element cooperating with the structure (4) made of magnetically conductive material, in order to form the inductor;

   the bus bar being formed by at least two sections (30; 30a, 30b) used successively by current circulating in this bus bar (6).
2. Component according to claim 1, each section (30) of the bus bar having the same form.
3. Component according to claim 1, the sections (30a, 30b) of the bus bar having different forms.
4. Component according to any one of the preceding claims, each section (30; 30a, 30b) of the bus bar (6) extending between a first face (31) and a second face (32), the first face (31) of a section being able to be positioned facing the second face (32) of another section, and the second face (32) of the section being able to be positioned facing the first face (31) of yet another section, in order to ensure the passage of the current from one section to the other, and one and/or the other of the first (31) and the second face (32) having as normal the direction (D) of propagation of the current in the said section (30; 30a, 30b).
5. Component according to any one of the preceding claims, each section (30; 30a, 30b) of the bus bar (6) extending between a first face (31) and a second face (32), the first face (31) of a section being able to be positioned facing the second face (32) of another section, and the second face (32) of the section being able to be positioned facing the first face (31) of yet another section, in order to ensure the passage of the current from one section to the other, and one and/or the other of the first and the second face not having as normal the direction (D) of propagation of the current in the said section (30; 30a, 30b).
6. Component according to claim 5, the first face (31) and/or the second face (32) of the section (30; 30a, 30b) being flat.
7. Component according to claim 5, the first face (31) and/or the second face (32) of the section (30; 30a, 30b) not being flat, in particular being curved, such as cylindrical, or being formed by intersecting planes.
8. Component according to any one of the preceding claims, the sections (30; 30a, 30b) being arranged such that the bus bar (6) extends straight along its entire length.
9. Component according to any one of claims 1 to 7, the sections (30; 30a, 30b) being arranged such that the bus bar (6) does not extend straight along its entire length.
10. Component according to any one of the preceding claims, the sections (30; 30a, 30b) being placed one after another, without defining a junction.
11. Component according to any one of the preceding claims, the sections (30; 30a, 30b) being placed such as to define at least one junction, in particular with two or three branches.
12. Component according to any one of the preceding claims, the bus bar (6) and the electrically conductive track (3) of the portion of printed circuit board (2) being connected electrically to one another via one or a plurality of attachments allowing current circulating in one section (30) of the bus bar (6) to circulate in the following section (30).
13. Voltage converter, in particular a DC/DC converter, in particular a 12 V / 48 V DC/DC converter, comprising a component according to any one of the preceding claims.

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