DE3423139A1 - Monolithic inductor having transformer applications - Google Patents

Abstract

A monolithic inductor has a block of dielectric material in which flat conductors are embedded at a distance from one another. The conductors are provided with a surface, which surfaces are in each case arranged essentially one above the other and from which the conductors lead outwards as spirals in opposite directions. The inductive impedance of the conductors is in this case greater than the capacitive impedance, so that the two conductors are electrically coupled to one another at radio frequencies.

Description

Monolithic inductor with transformer applications

The invention relates generally to monolithic electronic Devices and in particular monolithic inductors and transformers.

Electronic devices that consist of a dielectric block in which conductive layers or patterns are embedded are commonly referred to as monolithic. They are usually produced in a process in which metallized, conductive patterns are applied to a thin plate of dielectric material, e.g. ceramic, wherein the metallized plates are then stacked one on top of the other and then fired in the stack and then one Form a unified structure or a monolithic block.

Electrical connections can be made on the edges of the block,

where the conductive patterns touch the edges. _>

For example, a monolithic microminiature transformer is shown in U.S. Patent 3,833,872, with two separate, continuous windings of conductive metal film, each consist of a magnetically permeable coil made of refractory material, which is placed in a rectangular block of refractory Material layers, such as aluminum oxide, are housed. The primary and secondary windings of the transformer are through Imprinted or applied by photo-etching of coils on the rectangular ceramic plate during manufacture. The connection between the sheet-like turns is made by metallized Holes that are housed in the platelets or layers of the ceramic. U.S. Patent 3,838,320 shows a monolithic one Capacitor for high frequency, which has several conductive plates or electrodes that are spaced parallel to each other within a dielectric block are arranged. The US patent

3 745 431 shows a different arrangement of a monolithic capacitor with ceramic elements between them in layers electrodes are embedded inside. Similar, i.e., ply, devices are disclosed in U.S. Patents 3,484 731 and 4,253,079. The first patent shows a printed circuit with an inductor made up of a series spiral, conductive turns on a flexible, non-conductive material, for example Mylar. This Mylar strip is folded together so that the turns with their centers lie one above the other along a common axis. The individual turns are directly through conductive strips connected that extend beyond the folds or are arranged between the individual layers. In the second patent are Plates with spiral-shaped, conductive patterns arranged in a stack at a distance from one another to form an electrical coil form. A magnetic core is inserted into an opening which is provided in the middle area of the plates.

The creation of monolithic and layered electronic devices has now matured to the point where monolithic capacitors are more convenient and inexpensive By stacking metallized ceramic plates on top of one another and then firing them into a monolithic block can be formed in which layered conductive plates or patterns can be provided as a thick film, the each end at the edges of the block. Monolithic inductors and transformers and especially those with several Windings, however, have so far not been able to be produced in the same inexpensive way as capacitors. This is because because so far it has been necessary to electrically connect the individual windings to one another, the pattern or metallized layer Layers are molded on a monolithic block. Where a coil with several turns is metallized on a flat surface

one of its ends is surrounded by a spiral pattern in the center of the coil. To this end with another To connect the coil of an adjacent layer, it was necessary to provide an opening in the plate and to close it metallize to create a conductive path. The formation of such metallized openings in monolithic devices extremely small size is costly, unreliable, and results in devices that often fail. If on everyone If only one turn is provided on the surface, it is of course possible to attach each end of the turn of the flat coil to the Lead edge of the respective plate, so that the coils are then connected several layers by metallizing the sides of the block can be. Obviously, however, this is the case with coils having multiple turns within a spiral pattern not possible. The non-monolithic known methods avoid this problem by using a spiral pattern on flexible Material is applied, which is then folded up, are unsatisfactory because the temperature stability is insufficient is.

Accordingly, the present invention is intended for those just described Creating solutions to problems and limitations in the already known monolithic inductors and transformers.

In one embodiment of the invention, a monolithic Inductance a block of dielectric material in which two flat conductors are embedded at a distance from one another which are shaped together to form coil sections of a turn. The conductors are connected to surfaces, which are essentially one above the other, so that the capacitances are coupled to one another. Those so formed, at a distance from each other Arranged conductors form an electrically effective coil at radio frequencies.

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In another embodiment of the invention, the monolithic Multi-turn inductor for radio frequency use a sheet of dielectric material on / which separates two substantially flat conductors from each other, which are connected to substantially superimposed surfaces and surround them in opposing spirals.

In another embodiment of the invention, the monolithic Multi-turn inductor for radio frequency use. First and second plates of dielectric Material fused into a block. A first conductor is on a surface of the first plate of FIG of the second plate, arranged substantially in the form of a spiral extending from the edge of the first plate to the conductive Area leads there. A second conductor is generally in the form of a spiral on a surface of the second plate applied, which runs in the opposite direction to the former and leads from the edge of the second plate to the central conductive field, that is opposite to that of the first plate.

In a further embodiment of the invention, the monolithic Multi-turn inductor comprises a pair of fused dielectric plates covered with conductive, opposing spiral patterns are provided, which end in the middle in conductive surfaces and are thereby capacitively coupled to one another are to be electrically conductive at radio frequencies

In a further embodiment of the invention is a monolithic Transformer for use at radio frequencies made from a stack of dielectric, fused into a block Plates formed. The stack includes a first plate which has first and second substantially in one Planar, conductors separated from each other with central surfaces, which are arranged essentially one above the other, wherein opposing spirals at least part of a primary winding

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of the transformer. The stack has a second plate which has a third and fourth, substantially planar one Head with central mid-planes separating those on top of each other are arranged, with opposing spirals forming at least part of a secondary winding of a transformer.

Various embodiments of the invention are presented in the following Description explained in more detail with reference to the accompanying drawings. Show:

Fig. 1 is a perspective view of a monolithic

Inductance according to the present invention,

FIG. 2 is an exploded perspective view of FIG

monolithic inductance according to Fig. 2,

Fig. 3 is a schematic representation of the electrical

Circuit diagram of the monolithic inductance according to FIGS. 1 and 2,

Fig. 4 is a perspective view of another

embodiment of an inductor according to the invention with a turn,

Fig. 5 is a perspective view of another

embodiment of the inductance according to the invention with a three-quarter turn,

6 shows a perspective illustration with broken away

Parts to illustrate the internal structure of a monolithic transformer according to the invention,

7 is an exploded perspective view of Ores monolithic Transformer according to FIG. 6,

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Fig. 8 is an electrical circuit diagram of the monolithic

Transformer according to FIGS. 6 and 7.

Referring to Figures 1 and 2 of the drawings, there is a monolithic inductor shown, the seven dielectric plates 11 to 17 has, some of which are metallized with conductive Patterns are provided which are stacked on top of one another and then fused into a monolithic block. Each of the dielectric

/ tric plates is preferably made of a ceramic material, for example aluminum oxide, whereas the conductive patterns are metallized on some of the plate and preferably consist of thick film layers of silver or a palladium-silver alloy. In the case of the plate 1, only one corner is metallized, so that a corner connection 21 is produced, the remaining part of the plate being free of conductive material. The plate 12 is also metallized in one corner, so that a connection results from which a right-hand spiral 23 extends to a central central surface 24, the spiral having just one turn. The plate 13 is also metallized at one corner, so that a connection 25 results, from which a left-hand spiral 26 with one turn to a central middle surface

(27 extends towards. The plate 14 also has a metallized Corner connection 28 and is otherwise free of conductive patterns. The plate 15 has a metallized corner connection 29, of which from a right-hand spiral 30 with one turn leads to a central surface 31. The plate 16 is provided with a corner connection 32, from which a left-hand spiral 33 leads to a central surface 34, with only one turn also being provided. The plate 17 finally has a metallized corner connection 35 which forms the only conductive pattern on this plate.

The spirals and the central surfaces 24, 27, 31 and 34 are dimensioned and arranged in relation to one another so that the inductive resistance is much higher than the capacitive resistance. At-

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for example, when operating at one GHz, one

2 Area of the central surfaces of about 1.3 mm and a distance (Thickness of the ceramic plates), an inductive resistance of 0.05 mm, which is about twenty times greater than the capacitive resistance, which in detail depends on the geometry of the Spirals and the dielectric constant of the substrate. In this way, there will be a space between the adjacent central surfaces capacitive current flow at radio frequencies, i.e. at frequencies above 500 kHz. For special applications, in which the device should not work as an inductance, i.e. if it should be used in resonant circuits, the Set inductive and capacitive resistance to each other.

In operation, the corner connections 21 and 35 are connected to an electrical one Connected circuit and form a four-turn inductor. For the sake of simplicity, a AC current assumed heating season, with an instantaneous voltage peak. The current then flows from the corner connector 21 to the connection 22 and then via the spiral 23 to the surface 24. From here a capacitive current flows between the surface 24 on plate 12 and surface 27 on plate 13. The current flows then from the surface 27 via the spiral 26 to the connection 25. Since the spiral 23 makes a right turn and the spiral 26 a left turn, the current flows clockwise over the plates 12 and 13. The spirals 23 and 26 therefore together form a co-directional one Coil with two turns, i.e. there is a right turn when looking from above on the stack of plates in Figs 2 sees.

From the connection 25 on the plate 13, which both from the Oberais is also metallized from the underside, the current flows to terminal 28 on the plate 14 and then to terminal 29 on the

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Plate 15. The plate 14 serves to prevent the capacitive coupling between the surfaces 27 and 31, which would otherwise the coils 26 and 30 would short-circuit. From the connection 29 the current flows through the right-hand spiral 30 to the central area 31. From here, a capacitive current to the area 34 results the plate 16 via the spiral 33 to the connection 32. On the plates 15 and 16, the current flows again in a clockwise direction, as can be seen from Fig. 2, i.e. in the same direction as on the plates 12 and 13. From the terminal 32 the Current to terminal 35 on plate 17 and thus ends its path through the monolithic inductor. This is natural to take into account that only a half-period was considered here and that an opposite direction of flow occurs when the flow is opposite Voltage in the next half period.

Figure 3 is a schematic representation of the current flow path therethrough a monolithic inductor in which on the top plate a square spiral with two turns from a central surface 41 extends from and in the case of a further square spiral 42 with two turns of the on a lower plate Central surface 43 is arranged from. This figure is used to represent / that two opposing spirals in different Laying actually one continuous electrical coil with several Forms turns, the mechanically separated spirals being capacitively coupled to one another by the central surfaces 41 and 43 are.

In this way, inductances can be generated in which each spiral has several complete turns. It can however, more or less than one turn also occur. For example, FIG. 4 shows an embodiment of the invention, in which the monolithic inductor has only one turn.

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In this case is on top of a single dielectric Plate 45 metallized a half turn 46, which ends in a surface 47, in a similar manner on the underside of the Plate a half square turn 48 is metallized, which ends in a surface 49 which is arranged below the surface 47 is. In this simplified version, a single-turn coil is generated as long as the inductive resistance of the Areas 47 and 49 is much higher than the capacitive resistance. In this case, the faces are opposite to each other the same plate is metallized to produce a coil, with additional small sides or edges being metallized to create connections to be provided. Although it is preferable to apply cover plates of dielectric material to the top and bottom surfaces of the plate 45 are not shown here for the sake of clarity.

In Fig. 5 another embodiment of the invention is shown, in which a coil with a three-quarter turn is provided. Here is a plate 50 of dielectric material on the side 51 completely metallized, whereas the adjacent side is only metallized in one section 52. A right spiral 54 is Metallized onto the surface of the plate and ends in a surface 55, a surface 56 being provided on the underside of the plate which is connected to the pad 52 via a straight line 57.

6 to 8 shows a monolithic transformer according to the invention shown. The transformer 60 consists of twelve dielectric plates 61 to 72, which are stacked on top of one another and are fused together to form a block as shown in FIG. The top plate 61 does not carry any electrically conductive patterns, whereas the plate 62 directly underneath it carries a connection surface 75 on the front edge,

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from the one and a quarter turns of the right spiral 76 to one Central surface 77 lead. The plate 63 has a metallized surface 78 on the rear edge of which one and a quarter Windings of a left-hand spiral 79 lead to a central surface 80. The plate 64 is empty, i.e. it does not have any metallized ones Patterns on their surfaces. The plate 65 carries on the right side a connection surface 81 from which one and a quarter turns a right-hand spiral 82 lead to a central surface 83. The plate 66 carries a connection surface 84 on the left edge which lead from one and a quarter turns of a left-hand spiral 85 to the central surface 86. The plate 67 is free from metallized Patterns on their surfaces, whereas the plate 68 carries a pad 87 from which one and a quarter turns a right-hand spiral 88 lead to a central surface 89. The plate 69 carries a pad 90 on the leading edge of which leads from a left-hand spiral 91 to a central surface 93. the Plate 70 is again free of metallized patterns on its surfaces, whereas plate 71 has a connection surface on the right edge, from which one and a quarter turns of a right-hand spiral 96 lead to a central surface 97. In the end the plate 72 carries a connection surface 98 on the right edge, from which a left-hand spiral 99 leads to the central surface 100. Even here the middle surfaces on the adjacent plates are designed in such a way that that the inductive resistance is much higher than their capacitive resistance.

Once a unitary monolithic block is formed, be metallized strips applied to the side surfaces of the block, which the pads 78 on the plate 63 with the pad 87 connect on the plate 68, as shown schematically by the Leitei 101 is shown in FIG. Also is the pad on the plate 66 with a metallized strip on the side surface of the block with the connection surface 95 on the plate 71

bound, which is shown schematically by the conductor 102. The connection surface 75 is connected to a connection terminal A. and the pad 98 on a terminal C. The pad 81 is connected to a terminal B and the Pad 90 connected to a terminal D.

The device shown in FIGS. 6 and 7 represents a transformer, the circuit diagram of which is shown schematically in FIG is. In particular, it can be seen that a transformer winding is applied to terminals A and D and that on the other terminals B and C a second winding is provided. The winding on terminals A and D includes coils 76, 79, 88 and 91, which are connected in series and the winding at terminals B and C includes coils 82, 85, 96 and 99, which are also connected in series. The dielectric material of plate 62 forms a capacitor C1 with the surfaces and 80 as capacitor areas. The surfaces 89 and 93 represent the Represent areas of a capacitor C2 in connection with the plate 68, which dielectric is used. These capacitors C1 and C2 are in the winding at terminals A and D, but its inductive resistance is much higher than its capacitive resistance, so that they do not hinder the flow of current at radio frequencies. Similarly, surfaces 83 and 86 form the plates of one Capacitor C3 and the areas 97 and 99 are the areas of a capacitor C4. The inductive resistance of these capacitors is also much higher than their capacitive resistance at Radio frequencies. The circuit between terminals A and D and between terminals B and C within the monolithic Inductance thus represents the effective windings of a transformer, with the spiral pattern being the primary and secondary windings determine.

As can be seen, the monolithic inductance, which can also be designed as a transformer, overcomes the limitations

and disadvantages of known devices. It must be taken into account here / that the description was made only with the aid of a few special embodiments in order to explain the underlying principle of the invention. Modifications, additions
or omissions can of course be made to a large extent without infringing the inventive concept as it is also reflected in the patent claims.

Claims (1)

BIBRACM ^: SREH * E'R.Ö ^: 3A23139 LAW FIRM PATENT ADVERTISER DIPL.-1NQ. RUDOLF BIBRACH BIBRACH t REHBERG, POST BOX 14-53,0-3400 GÖTTINGEN »v /«. I ^ u μ PATENT Attorney DIPL-INQ. ELMAR REHBERQ LAWYER MICHAELA BIBRACH-BRANDiS TELEPHONE: (0551) 45034/35 TELEX: 96610 bipat d CHECK ACCOUNT: HANNOVER (BLZ 15010030t NO.115763-301 BANK ACCOUNTS: DEUTSCHE BANK AG GÖTTINNEN (BLZ Z6O7OO78) NO. 01/85900 COMMERZBANK GOTTINGEN (BLZ 26040030! NO. 642572Ϊ YOUR SIGN YOUR LETTER FROM OUR SIGN D-3400 CJÖTTINCJEN, YOUR REF. YOUR LEHER OUR REF. POHERWEq 6 11.729 / n8 June 21, 1984 Murata Eria N.Α., Inc., 1148 Franklin Road, Marietta, Georgia 30067 / USA Monolithic inductor with transformer applications ^ Patent claims: \ 1J A monolithic inductor with a block of dielectric Material, characterized in that two flat conductors are embedded in the block at a distance from one another and which are common Form a co-directional coil section, the conductors having capacitively coupled guide surfaces arranged one above the other are connected in such a way that the two conductors form an electrically effective coil at radio frequencies. 2. A monolithic inductor according to claim 1, characterized in that that the two flat conductors taken together form a coil section of at least half a turn. 3. A monolithic inductor according to claim 1, characterized in characterized in that the inductive resistance is significantly higher than the capacitive resistance between the guide surfaces. 4. A monolithic inductor according to claim 1, characterized in that at least one of the planar conductors to a spiral which ends in one of the baffles. 5. A monolithic multi-turn inductor for use at radio frequencies characterized by: that a sheet of dielectric material separates two substantially planar conductors, the two substantially Have central guide surfaces arranged one above the other, from which they extend outward in opposing spirals. 6. A monolithic multi-turn inductor according to claim 5, characterized in that the inductive Resistance is much higher than the capacitive resistance of the conductor. 7. A monolithic multi-turn inductor for use at radio frequencies, characterized in that that first and second sheets of dielectric material are fused into a block, on one surface of the first plate a first conductor on the opposite side of the second plate in a substantially spiral shape Pattern is applied extending in a direction of rotation from the edge of the first plate to a first guide surface and a second conductor on a surface of the second plate substantially helically in the opposite sense from the edge the plate is applied to a second, the first guide surface opposite, guide surface extending towards. 8. A monolithic multi-turn inductor according to claim 7, characterized in that the conductor is on is arranged on a surface of the second plate which faces the first plate. 9. A monolithic inductor according to claim 7, characterized in that the block has multiple sides and is the first conductor extends to one of the block sides and the second conductor extends to another block side. 10. A monolithic multi-turn inductor characterized in that a pair of fused together Plates of dielectric material carry conductive spiral patterns which are designed in opposite directions and in central baffles ends that are sufficiently capacitively coupled that they are electrically conductive at radio frequencies. , 11. A monolithic multi-turn inductor according to claim 10, characterized in that the inductive resistor is much higher than the capacitive resistance of the conductive pattern. 12. A monolithic multi-turn inductor for the use at radio frequencies, characterized in that a stack of dielectric plates fused into a block is, wherein a first plate has a first and second, substantially planar, conductors with superimposed central Guide surfaces, from which opposing spirals extend, separates from each other, which together at least part of a Form the primary winding of a transformer, with a second plate having a third and fourth, essentially flat, conductor with superimposed central surfaces, from which opposing spirals extend, separates from each other, the min- at least part of a secondary winding of a transformer form. 13. A monolithic multi-turn inductor according to claim 12, characterized in that the inductive resistance is significantly higher than the capacitive resistance every leader.