The invention relates to an electronic component for realizing an inductance, in particular of a transformer, and a production process for an electronic component.
The prior art discloses planar coils in which the coil turns are put onto the surface of a substrate. Such known planar coils can achieve only a relatively small inductance in a cost-effective way, and the planar coils also occupy a relatively large amount of space on the substrate surface.
DE 10 2012 216101 discloses a process for producing a coil that is integrated into a substrate or put on a substrate, this process involving turn sections of the coil passing through the core material of the coil.
US 2012/0011709 A1 discloses a discrete electronic component with an inductance, this component having a cylindrical coil core.
The publication US 2009/0237899 A1 discloses a magnetic component that is arranged in a printed circuit board. To accomplish this, the printed circuit board has a recess in which an E-shaped core element can be put. This E-shaped core element can have a coil put in it, and a rod-shaped element can be provided on the top of the E-shaped core element.
By contrast, the invention has the goal of creating an improved electronic component and a process for producing it.
Each of the goals of the invention is achieved by the features of the independent claims. Embodiments of the invention are specified in the dependent claims.
According to embodiments of the invention, the electronic component has a cavity, in which a magnetic circuit is arranged. The magnetic circuit is formed by at least one planar coil, which is located between first and second magnetic conductor elements. Each of the magnetic conductor elements has a first end, the first ends being arranged opposite one another and extending in the axial direction of the planar coil. The first ends of the magnetic conductor elements, these first ends lying opposite one another, form a coil core for the planar coil.
The second ends of the magnetic conductor elements are arranged on the periphery of the planar coil and lie opposite one another there. Each of the magnetic conductor elements has at least one bridge-shaped area that connects together the first and second ends of the magnetic conductor element in question, closing the magnetic circuit. Each of the bridge-shaped areas of the magnetic conductor elements can extend parallel to the plane of the planar coil between its center and its periphery, so that the turns of the planar coil pass through between the first and second ends and the bridge-shaped areas lying opposite one another of the two conductor elements that are arranged opposite one another.
Embodiments of the invention are especially advantageous since the electronic component can achieve a relatively large inductance while having a relatively small mass. Furthermore, [use of] the planar coil allows the electronic component to have a small overall height, so that if the electronic component is arranged on a printed circuit board, for example, only a small moment of tilt results, even at high accelerations. Therefore, embodiments of the electronic component are especially suitable for means of transport such as, for example automobiles, airplanes, and ships, in which high mechanical stresses can occur, and/or for applications, in which reliability is especially important, such as, for example medical technology devices, especially implants.
Embodiments of the invention are also especially advantageous, since it is possible to realize a relatively large inductance with a relatively small ohmic resistance, and thus the reactive power and waste heat are correspondingly small. The electronic component can have, for example, a power consumption between 10 watts and 100 watts, in particular 50 watts.
According to embodiments of the invention, each of the first and second magnetic conductor elements has multiple bridge-shaped areas, each of which is arranged around the first ends, for example in the shape of a star, especially in the shape of an x. The individual bridge-shaped areas of one of the magnetic conductor elements can be arranged around the first end of the magnetic conductor element in question, at the same or different angular distances.
According to embodiments of the invention, the at least one planar coil is put on a printed circuit board layer. The planar coil is produced, for example, in a separate manufacturing process, for example a lithographic process, in order then to use the planar coil to produce the electronic component.
According to one embodiment of the invention, the electronic component comprises a first planar coil to form the primary side of a transformer, and a second planar coil to form the secondary side of a transformer. The first and second planar coils are arranged between the first and second magnetic conductor elements, the first ends forming the coil core, i.e., here the transformer core of the transformer.
For example, the planar coils can be designed to be mirror symmetric with respect to one another by producing them with identical lithographic processes. This has the advantage that it makes it possible to achieve a small manufacturing tolerance of the electronic component.
According to one embodiment of the invention, the first and/or second planar coils, for example, are formed by the planar coil in question having a first part of its turns on a first side of its printed circuit board layer and a second part of the turns of the planar coil being arranged on the second side of the printed circuit board layer opposite the first side. The first and second parts are connected by a via through the printed circuit board layer, resulting in a planar coil that has the turn sections on the two opposite sides of the plane formed by the printed circuit board layer. This has the advantage that it can further increase the inductance at low cost, using little material, and with small overall height.
According to embodiments of the invention, a coil package, for example with one planar coil or with first and second planar coils, is created as a structural unit by providing other printed circuit board layers as insulating layers for the coil turns. Such a structural unit can be produced in a separate process, in order then to use the structural unit to produce the electronic component, by putting the structural unit between the first and second magnetic conductor elements.
According to one embodiment of the invention, the first and second magnetic conductor elements are designed so that the end faces of the respective opposite second ends touch one another, creating especially good mechanical stability. In particular, tilting of the magnetic conductor elements relative to one another is avoided, even under large mechanical loads, since the second ends of the magnetic conductor elements rest on one another.
According to one embodiment of the invention, there is an air gap between the first ends of the conductor elements in the center of the at least one planar coil. Such an air gap can be advantageous, to avoid an operating point in the magnetic saturation. In particular, the air gap allows the electronic component to operate in the approximately linear range of the hysteresis loop of the magnetic circuit. On the other hand, the air gap between the first ends is also mechanically advantageous, since it avoids a double fit requirement with respect to the second ends, and produces a defined mechanical contact at the opposite second ends.
According to one embodiment of the invention, the cavity in which the magnetic circuit is arranged is formed by one or more printed circuit board layers of the electronic component, the printed circuit board layers having a coefficient of thermal expansion that is greater than that of the ferrite of which the magnetic conductor elements consist. Then, if the temperature increases, the cavity expands more than the magnetic circuit does, so that a gap can form between the magnetic circuit and the cavity. In order to fix the magnetic circuit securely within the cavity even if the temperature increases, an elastic element can be arranged in the cavity to avoid the formation of such a gap due to a temperature increase. The elastic element can be a spring element and/or a foam, for example polyurethane.
According to one embodiment of the invention, one or more of the spring elements is/are formed in a printed circuit board layer, for example by pressing in and/or laser processing. Such a printed circuit board layer with spring elements can be integrated in the electronic component, each of the spring element(s) being located in one of the cavities, in order to compensate for the tolerances there due to a temperature increase.
According to one embodiment of the invention, the sum of the end faces of the second ends of the magnetic conductor elements is equal to the sum of the end faces of the first ends. That is, if each of the magnetic conductor elements has only one second end, the end faces of the second ends are the same size as the end faces of the first ends, so that the cross section of the magnetic circuit is approximately equal at each of the first and second ends.
By contrast, if each of the magnetic conductor elements has multiple second ends, such as, for example two, three, or four second ends in an x-shaped formation, then in the latter case every end face of the second ends has approximately a quarter of the end surface of the second end, so that even in this case the magnetic circuit once again also has an approximately equal effective cross section at the first ends and the second ends, which is advantageous for conducting the magnetic flux.
Another aspect of the invention relates to a printed circuit board, which can have a single-layer or multilayer design, with an inventive electronic component that can be arranged on or in the printed circuit board. In particular, the electronic component can be in the form of a discrete electronic component. The electronic component can have, for example, connection contacts produced using the SMD technique, these connection contacts producing electrical contacts with a circuit of the printed circuit board and fixing the electronic component on the printed circuit board.
According to one embodiment of the invention, the electronic component is in the form of a transformer and serves to make available an operating voltage for a circuit of the printed circuit board. The circuit of the printed circuit board can serve, for example, to drive a light-emitting diode, such as, for example for the light-emitting diode of an automobile headlight.
Another aspect of the invention relates to a production process for an electronic component. First, a coil package consisting of one or more planar coils is produced. The coil package is put between the first and second magnetic conductor elements and put into a cavity of a single-layer or multilayer printed circuit board.
According to one embodiment of the invention, the individual components of the electronic component are first arranged in a stack structure, which is formed into a structural unit in a so-called multilayer process by applying pressure at a high temperature.
Embodiments of the invention will be explained in detail below with reference to the figures. The figures are as follows:
In the following description of the embodiments, elements that correspond to one another or are the same are always labeled with identical reference numbers.
Each of the printed circuit board layers can be a so-called prepreg. In particular, it can be a glass fiber mat soaked with epoxy resin (for example, FR-4 materials).
The cavity 4 has a magnetic circuit arranged in it, which is formed by a first magnetic conductor element 5, a second magnetic conductor element 6, and a coil package 7 arranged between the conductor elements 5 and 6, this coil package 7 having at least one planar coil. The magnetic conductor element 5 has a first end 8, which projects in the axial direction into a central opening of the coil package 7. The magnetic conductor element 5 also has two second ends 9′ and 9″ on the periphery of the coil package 7.
The magnetic conductor element 6 has a corresponding first end 10, which is opposite the first end 8 in the central opening of the coil package 7, and second ends 11′ and 11″, which are opposite the second ends 9′ and 9″. For example, the magnetic conductor elements 5 and 6 are identical, so that if the component 1 is mass produced, the same components can be used to realize the conductor elements 5 and 6.
The conductor elements 5, 6 can be bow-shaped, for example. In the embodiment of
Each of the magnetic conductor elements 5, 6 consists of a ferrite having a high magnetic permeability.
In the representation according to
According to embodiments of the invention, the end faces of the second ends 9′ and 11′ or 9″ and 10″ lie on top of one another, while an air gap 14 remains between the end faces of the first ends 8 and 10.
The procedure to produce the primary coil 15 involves first applying a first part 17 of the turns of the primary coil 15, for example on the top of a printed circuit board layer 18, for example using a lithographic process, and, by contrast, applying a second part 19 of the turns of the primary coil 15 on the bottom of the printed circuit board layer 18. The parts 17 and 19 of the primary coil 15 are electrically connected with one another by a feedthrough 20, that is, a so-called via through the printed circuit board layer 18. The resulting primary coil 15 has connection contacts 21 and 22.
The procedure to produce the secondary coil 16 is analogous, and involves applying a part 23 of the turns of the secondary coil 16, for example on the top of a printed circuit board layer 24, and applying a second part 25 of the secondary coil 16 on the bottom of the printed circuit board layer 24, the parts 23 and 25 being electrically connected with one another by a feedthrough 26 (cf.
In the third step (
In the fourth step, the coil package 7 is then formed (
In the embodiment according to
For example, the circuit 38 is a drive circuit for an automobile headlight.
Embodiments of an inventive electronic component can be used as an interference suppression choke, in particular a current-compensated choke or a common mode choke (CMC). Such current-compensated chokes are known in the prior art and are used to suppress emitted interference. For common-mode interference, a current-compensated choke forms a very high inductance, since the interfering currents are not compensated in it. To accomplish this, current-compensated chokes are used at the inputs and outputs of switched mode power supplies and in network filters, especially also in LAN transformers.
Here component 1 has 4 terminals and, according to the embodiment according to
The transformer 41 has the signal inputs d and f and the ground conductor e. On the output side, the transformer 41 has the ground conductor c and is connected with the connection contacts a′ and b′ of component 1, in order, for example, to couple in an input signal applied to the signal inputs d and f through the transformer 41 and the common mode choke formed by the component 1 into a LAN cable, which is located on the side of the common mode choke 1.
According to embodiments of the invention, an inventive component 1 is used to realize a DC-DC converter, in particular a capacitor-coupled switching regulator, in particular for a SEPIC converter (abbreviation for single ended primary inductance converter), a CUK converter, or a zeta converter.
The SEPIC converter according to
Number | Date | Country | Kind |
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10 2106 203 613.0 | Mar 2016 | DE | national |
This application is a national stage application of and claims priority to International Patent Application No. PCT/EP2017/054872 entitled “Electronic Component and Method for the Production Thereof” filed on Mar. 2, 2017, which claims priority to German Patent Application No. DE102016203613.0 entitled “Elektronisches Bauelement and Verfahren zu dessen Herstellung” filed on Mar. 4, 2016, both of which are incorporated herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/054872 | 3/2/2017 | WO | 00 |