KR100735208B1 - Multi-Layer Transformer having Electrical Connection in a Magnetic Core - Google Patents

Abstract

A method, apparatus and article of manufacture for a multilayer transformer 132, the multilayer transformer comprising first windings 126, 128 disposed on at least one layer and second windings 178, 180 disposed on at least one layer. And a plurality of layers 168 through 174 having magnetic core regions disposed in each layer forming the magnetic core of the excitation transformer. The plurality of interconnecting vias 130 connects the first winding between the layers, and the plurality of second interconnecting vias 130 connects the second winding between the layers. The interconnect vias are placed close to the center of the transformer's magnetic core, thus reducing the overall volume, size, weight and price of the transformer, while at the same time meeting regulatory insulating safety requirements.

Description

Multi-Layer Transformer having Electrical Connection in a Magnetic Core

The present invention relates to a transformer, and more particularly to a multilayer ceramic transformer

(multi-layer ceramic transformer) and a method of manufacturing the same.

The transformer of the conventional structure includes a winding and a core, which is a magnetically permeable area. The windings generally consist of insulated conductive wires, usually surrounding the magnetic core. The winding also wraps around an insulating bobbin located around a magnetic core. Transformers generally have different turns and enclosures, including first and second windings.

It includes a plurality of windings of a wrap.

Conventional transformers have long included separate magnetic cores and winding regions, in which case the winding regions have limitations in terms of the positioning of the winding relative to the core. Typically the windings are wound around the magnetic core, increasing the overall size and volume of the transformer. When using the structure of the current technology, it is impossible for the windings to physically penetrate the core area, which requires a great deal of time and money. Furthermore, most possible circuit paths through the magnetic core material tend to induce unwanted magnetic fields in addition to the magnetic fields provided by the design. Thus, wrapping the windings around the magnetic core region limits the options for reducing the size of conventional transformers. Reducing the size of an isolation transformer is often difficult, because the physical size and structure of the isolation transformer plays a role in its electrical insulation properties.

In addition to physical size limitations, conventional transformers used in telecommunications applications must comply with regulatory safety standards, which are more commonly used to insulate user electronics from telecommunications networks, such as telephone networks. Because. Many regulatory agencies require that transformers provide a barrier for insulating certain bolts and meet specific clearance and creepage distance requirements within the transformer.

A "clearance distance" is defined as the shortest distance between two conductive parts measured through air, which is particularly important, although air is a good insulator, it will eventually ionize and destroy the insulation barrier if given a strong enough electromagnetic field in the air. Because.

The "creepage distance," which is defined as the shortest distance between two conductive parts measured along the surface of the insulator, is also very important, given the sufficient electrical potential between two points on the surface of the insulator, under adequate environmental conditions and sufficient time, This is because the surface of the break eventually breaks down, leading to a breakdown of its insulating properties.

Conventional transformers meet distance and bolt insulation requirements by using insulating tape, crossover tape, varnish, epoxy, insulated wire and plastic bobbins. They are used in various combinations to ensure that the transformers support the desired bolt break limits and specific distances.

In addition to the limitations of physical size and electrical insulation properties, conventional transformers are not easy to manufacture in an automated process. Conventional wire winding type transformer is wound lead

Due to the need to weld (winding leads) to bobbin terminals, it is difficult to manufacture in an automated process. In addition, surrounding the windings and keeping them separate from each other during the manufacturing process is more difficult and requires a lot of manual work for assembly. Even when regulatory requirements change to require higher bolt insulation, additional transformers are needed and the price of the transformer rises above what the market can afford.

In order to overcome the limitations of conventional transformers, numerous ceramic transformer manufacturing methods have been disclosed. However, many of these ceramic transformers do not sufficiently address electrical insulation requirements, such as the physical requirements required to provide adequate bolt breakdown protection.

In addition, conventional ceramic transformers that meet safety requirements often do not provide adequate functionality, such as poor coupling between coils of conventional ceramic transformers.

Accordingly, there is a need in the art for improved transformers and methods for their manufacture, in particular, low cost, small ceramic transformers that can be easily mass-produced in an automated manner and that also meet regulatory safety requirements.

In order to overcome the aforementioned limitations of the prior art and to overcome other limitations evident by the present disclosure, the present invention provides a method of providing a multilayer transformer with reduced physical size and volume without adversely affecting electrical insulation properties. And a device.

In one embodiment, the invention provides a plurality of layers defining a magnetic core area disposed over two or more layers forming a magnetic core of a transformer, a primary winding disposed over one or more layers, one or more layers. A multilayer tape comprising a secondary winding disposed above, a plurality of first interconnect vias connecting the primary windings between the layers and a plurality of second interconnect vias connecting the secondary windings between the layers A transformer having a multi-layer tape structure is disclosed, wherein the first and second interconnect vias are disposed close to the center of the magnetic core of the transformer.

In addition, in one embodiment of the present invention, the layers provide a layer of cofired ceramic material.

Furthermore, in one embodiment of the present invention, the co-heated ceramic material is a Low-Temperature-Cofired-Ceramic (LTCC) material.

In an alternative embodiment of the present invention, the co-heated ceramic material is a High-Temperature-Cofired-Ceramic (HTCC) material.

One advantage of the present invention is that the total volume of the transformer is reduced, and the amount of material required for the manufacture of the transformer is reduced, resulting in a significant reduction in the overall cost and weight of the transformer.

The present invention provides a multi-layer transformer having interleaving windings. In one embodiment, the multilayer transformer comprises a plurality of layers defining a magnetic core region disposed on at least two layers forming a magnetic core of the transformer, a first winding disposed on a first layer, and a second winding disposed on a second layer. Wherein the first and second layers are positioned adjacent to each other such that the first and second windings have an interleaving relationship, from one layer to the other.

In another embodiment of the invention, the transformer further comprises a plurality of first interconnecting vias connecting the first winding between the layers and a plurality of second interconnecting vias connecting the second winding between the layers. Include.

In addition, in one embodiment, the first and second interconnect vias are disposed close to the center of the magnetic core of the transformer.

Further, in one embodiment, the starting and finishing ends of the first windings are disposed on the same end layer of the plurality of layers, at one end of the transformer.

In one embodiment, the starting and finishing ends of the second winding of the multilayer transformer are disposed on the same terminal layer of the plurality of layers, at one end of the transformer.

In one embodiment, the starting and finishing ends of the transformer, the first and second windings, are disposed on one end of the transformer on the same end layer of the plurality of layers.

In one embodiment, the plurality of layers of the transformer is a ferromagnetic cofired ceramic tape. The co-heated-ceramic tape is made of low temperature-co-heated-ceramic (LTCC).

In an alternative embodiment, the coheated ceramic tape is made of hot-coheated-ceramic material (HTCC).

In one embodiment, the first and second windings are first and second electrically conductive members disposed in at least the first and second layers, respectively, in a magnetic core, wherein the first on the first layer is formed. The first conductive member has an end connected between the first and second layers via the via to the end of the second conductive member on the second layer, wherein the first and second layers are adjacent to each other and the conductive member is Generally perpendicular to the flux line of the magnetic core, a portion of the first conductive member disposed close to the via is parallel to a portion of the second conductive member disposed close to the via, and the two portions are opposite to each other. Direction, conducts an equal current, thereby substantially eliminating magnetic effects around the vias.

Further, in one embodiment, the first and second windings disposed in adjacent layers are separated by a first distance, the first distance being a gap between two adjacent portions of the first conductive member of the first winding on the same layer. It is smaller than the second distance, which is a spacing distance.

In another embodiment, the first and second windings disposed in adjacent layers are separated by a first distance, wherein the first distance is the distance between two adjacent portions of the second conductive member of the second winding on the same layer. Less than the second distance.

In another embodiment, the first and second windings disposed in adjacent layers are separated by a first distance, wherein the first distance is the spacing distance between the first and second conductive members of the first and second windings, respectively. Is less than the second distance.

In addition, in one embodiment, the first winding is in the shape of a spiral.

In yet another embodiment, the second winding is in the shape of a spiral.

In another embodiment, at least a first winding disposed on the first layer generates a first magnetic flux, and at least a second winding disposed on the second layer is wound by the first magnetic flux. Combined with.

One advantage of the present invention is that the net current in the first and second electrically conductive members around the via is zero, so that the flux lines from the transformer do not change significantly. Thus, no significant spurious magnetic field is introduced into the transformer core region.

Another advantage of the present invention is that the magnetic coupling between the windings is significantly improved.

The present invention also provides a balanced multi-layer transformer. In one embodiment, the transformer consists of at least one layer with windings disposed in at least one layer, windings for generating magnetic flux, and magnetic core regions formed by the windings, wherein the magnetic core regions are substantially perpendicular to the magnetic flux. to be. The plate disposed on top of the at least one layer provides a return path for the magnetic flux, wherein all of the plate cross-sectional areas covered by the magnetic flux are substantially free of magnetic flux.

(traversed) equal to the magnetic field region

The present invention also provides a balanced multilayer transformer. In one embodiment, the transformer consists of at least one layer with windings, windings for generating magnetic flux, magnetic core regions formed by windings, wherein the magnetic core regions are substantially at a magnetic flux. Vertical. The plate disposed at the top of the at least one layer provides a return path for the magnetic flux, wherein all of the plate cross-sectional area covered by the magnetic flux is larger than the magnetic core region covered by the magnetic flux.

One advantage of the present invention is to recognize a balanced transformer with a balanced cross-sectional area, maximizing the magnetic flux density for a given size.

The present invention provides a ferromagnetic material for a ceramic transformer. The plurality of layers constituting the magnetic core may be formed of such a ferromagnetic material. In one embodiment, the ferromagnetic material comprises nickel-copper-zinc-ferrite (NiCuZnFeO), wherein the ferrite (FeO) content is 40 to 60% of the total weight. The ferromagnetic material also contains bismuth (Bi) in an amount of 1% or less of total weight percent and zinc oxide (ZnO) in an amount of 10% or less of total weight percent, in which case after heating the ceramic transformer, zinc oxide The particle size is 10 μm or less.

Many other novel advantages and features that characterize the invention are pointed out in the claims that follow and form part of the invention. However, in order to better understand the present invention, its advantages, and the objects obtained by using the same, a description is given of the drawings, which form a part of the present specification and which describe the embodiments of the present invention.

Hereinafter, like the reference numerals will be described with reference to the drawings showing the corresponding parts throughout.

1 A and B show side and sectional views of a conventional wound transformer.

2 is a plan view of a top layer of a multilayer transformer, in accordance with a preferred embodiment of the present invention.

3 shows a transformer winding layer showing current flow within one polarity, according to a preferred embodiment of the present invention.

FIG. 4 illustrates another transformer showing current flow within the opposite polarity of FIG. 3, in accordance with a preferred embodiment of the present invention.

FIG. 5 shows, in accumulation arrangement, two transformer winding layers shown in FIGS. 3 and 4, in accordance with a preferred embodiment of the present invention, further depicting current and corresponding magnetic flux polarity in each layer.

6A and 6B show a magnetic flux path with separate first and second windings on one layer of a conventional multilayer transformer.

7A and B illustrate the first and second windings and magnetic flux paths in close proximity on individual layers of a multilayer transformer according to a preferred embodiment of the present invention.

8A, B illustrate a plan view of one layer and the cross-sectional area of a multilayer transformer, in accordance with a preferred embodiment of the present invention.

9 shows an exploded view of a multi-layer transformer according to a preferred embodiment of the present invention.

10 illustrates regions of a balanced multilayer transformer in accordance with a preferred embodiment of the present invention.

11 A. B, and C show top views of three embodiments of different spiral winding patterns, in accordance with a preferred embodiment of the present invention.

The present invention provides a transformer having a multilayer tape structure. The present invention also provides a multilayer transformer having first and second windings coupled in an interleaving relationship. The present invention further provides a balanced multilayer transformer. In addition, the present invention provides a ferromagnetic material for a transformer.

In the following description of the preferred embodiments, reference is made to the drawings, which form a part thereof, in which case the drawings are represented by a way of illustrating a particular embodiment in which the invention may be practiced. Other embodiments are possible, and structural changes are possible without departing from the scope of the present invention.

1A shows a side view of a conventional transformer depicting a winding having a starting lead 46 and a terminal lead 48 wound several times around the insulating bobbin 44. The winding comprises an insulated conductive wire. The current flowing through windings 46 and 48 generates a magnetic field. The magnetic flux line is perpendicular to the winding. The magnetic flux lines generated in this way are concentrated or strengthened by passing through the magnetically permeable core 42 with low or no resistance to the construction of the flux line. In order to further ensure low magnetoresistance, a closed magnetic path 40 is established in the magnetic core 42. Another embodiment of a conventional transformer typically has two or more windings, consisting of first and second windings, requiring four or more wire connections to the core.

FIG. 1B shows a cutaway view of the cross-sectional area A-A of the conventional transformer of FIG. 1A.

The core cross-sectional area is perpendicular to the flux path 40 (FIG. 1A). In order to meet the optimum flux density grade of the core material and the application electrical requirements, such as inductance, it is important to optimize the overall size of the cross-sectional area 42 of the core. An additional description of the winding area 50 was included to clarify that the windings surround the winding core 42 portions and do not penetrate the center of the core 42.

2 shows a top layer of a multilayer transformer, in accordance with a preferred embodiment of the present invention. The top plate 61 of the multilayer transformer may include four conductive terminal pads and four conductive through holes (hereinafter referred to as via 60). The conductive terminal pads correspond to the first winding starting lead and the first winding ending lead 52 and 54, respectively. The other conductive terminal pads 56 and 58 correspond to the 2nd winding start lead and the 2nd winding end lead, respectively. Top plate 61 and all subsequent layers are cold-coated ceramic materials.

(LTCC) or high temperature co-heat ceramic material (HTCC) or the like. The first and second windings are laid on several layers and are interconnected through conductive vias 60 between the several layers. The starting and terminal leads of the first and second windings end on the outer surface 63 of the plate 61. The conductive via 60 is generally located toward the inner portion of the plate 61. In this embodiment, the terminal pads of the first winding and the second winding are located on the same plate. Terminal pads for the first and second windings may be placed on different plates or layers.

3 shows layer 76 of a multilayer transformer according to a preferred embodiment of the present invention. The conductive material is printed on the ferrite tape substrate to form an electrically conductive member or winding 62. The current flowing through the winding 62 produces a magnetic field 64 perpendicular to and surrounding the winding 62. The polarity of the magnetic field 64 depends on the direction of the current. Each subsequent layer of the multilayer transformer has a similar winding. Each winding having one or more turns with a starting end and a finishing end is electrically connected through conductive via 60 to conductive terminal pads 52, 54, 56 or 58 (FIG. 2). The number of revolutions per first and second windings is determined by the given specifications of the transformer. The winding 62 divides the ferrite tape substrate into an inner core portion 68 and an outer core portion 66. The conductive via 60 is preferably located in the inner core 68 to reduce the size of the transformer. Vias or portions of vias may be located outside of inner core portion 68. Thus, in one preferred embodiment, all conductive vias can penetrate the inner core portion 68 from layer 76 to adjacent layer 74 (FIGS. 4 and 5). By interconnecting the conductive windings 62 through the inner core 69 using vias 60, the overall volume of the transformer is significantly reduced while not adversely affecting the magnetism of the transformer.

4 shows layer 74 of a multi-layer transformer, in accordance with a preferred embodiment of the present invention. The conductive winding 72 is printed on the ferrite tape substrate. The current flowing through the winding 72 creates a magnetic field 70 perpendicular to and encircling the winding 72. The polarity of the magnetic field 70 is determined according to the direction of the current and has the opposite polarity for the magnetic field 64 (FIG. 3) occurring on the adjacent layer 76 (FIG. 3) of the transformer. Winding 72 has one or more turns. The starting and finishing ends of the windings may be electrically connected through conductive vias 60 to conductive terminal pads 52, 54, 56 or 58 (FIG. 2). Winding 72 divides the ferrite tape substrate of layer 74 into an inner core portion 69 and an outer core portion 67. Conductive via 60 is preferably located on inner core 69. Thus, all conductive vias may penetrate the inner core 69 from layer 74 to layer 76. Similarly, the number of first and second windings is determined according to the given specifications of the transformer.

Figure 5 shows the layers of layers 76 and 74 of a multilayer transformer according to a preferred embodiment of the present invention. 76 and 74 may be two adjacent layers of a multi-layer transformer, or may be a two-layer transformer. Conductive winding 62 of layer 76 is electrically connected to conductive winding 72 of layer 74 using conductive via 60. The current flowing into the winding 62 produces a magnetic field 64 with the polarity of the magnetic field being the opposite of the magnetic field 70 generated by the conductive winding 72 on the layer 74. The polarities of the magnetic fields 64 and 70 surrounding portions of the conductive windings 62 and 72 located in the central core region of the transformer are directly opposite one another and cancel out. As a result, the net magnetic field in the central core region is zero. Due to this feature, interconnecting windings can penetrate the central core region of the multilayer transformer without adversely affecting its magnetic properties. In addition, the overall volume and cost of the transformer is also reduced.                 

A preferred embodiment of the present invention provides a balanced, multilayer transformer, which meets safety standards or requirements for breakdown voltage. In any application where a transformer is connected between the user equipment and the telephone line, insulation voltages up to 1500V AC may be required. Insulation bolts between the first and second windings often need to be about 1.6 times the value without excess leakage current through the transformer. In a preferred embodiment, the multi-layer transformer may comprise a layer having a thickness of 0.0035 inches. The thickness of the layer is substantially equal to the distance between the first and second windings. The layer thickness is a tradeoff between achieving good magnetic couple between the windings and providing adequate insulation protection. For example, thicker layers between windings provide better insulating properties than thin layers. However, since the distance between the windings is increased, the magnetic coupling of the thick layer is worse than the magnetic coupling of the thin layer.

In order to improve the magnetic coupling and insulation properties between the first and second windings in a multilayer transformer, the present invention provides an improved material for the transformer. In one preferred embodiment, the material comprises a nickel-ferrite base material (NiCuZnFeO) having about 50% ferrite by weight. In order to increase the insulation protection or dielectric voltage, the amount of Bi present in the composition of the base material is minimized to a trace amount and the percentage content of Zn is also reduced. The base material can be essentially a semiconductor. By reducing the amount of Zn in the composition and milling the Zn particles to a size of 5-10 μm in diameter or less, the threshold voltage is high enough to control the leakage current to an acceptable level. The actual percentage content of Zn used in the composition depends on factors such as Zn particle diameter, impurity content in the composition, and overall thickness between the first and second layers of the transformer layer. For example, in one preferred embodiment, having a thickness of 0.0035 inches, the Zn content is less than 10 weight percent (wt%) and less than 4 atomic weight percent. Other layer thicknesses may be used based on the desired minimum insulation voltage and leakage current for a particular application. In order to meet various requirements, it is possible to vary or adjust the Zn particle diameter, percentage content and layer thickness within the scope of the present invention.

In general, improving the coupling coefficient between the individual windings of a transformer also requires further adjustment of the physical layout of the individual windings. The windings are kept in close physical proximity to each other by reducing the thickness of each ceramic layer, and by bonding through the central core region, as shown in FIGS. The closer the windings are to each other, the more magnetic flux lines pass through each winding, thereby increasing the coupling coefficient of the transformer and leading to a better transfer of the electrical signal.

6A and B show a cutaway and cross-sectional view of a conventional transformer 96 with a long magnetic path 98, which results in a poor coupling between the first winding 100 and the second winding 102. FIG. 6B shows the first winding 100 for the second winding 102 and the distance X between them that must be maintained to prevent dielectric breakdown. In the conventional transformer, X is a distance between two windings on the same layer.

7A and B illustrate a blow up view and a cross-sectional view of a transformer 110 in accordance with one preferred embodiment of the present invention. In the case of the transformer, a much shorter magnetic path 112 results in good coupling between the first winding 182 and the second winding 184. In this preferred embodiment of the invention, the arrangement between the first and second windings is arranged such that a maximum number of magnetic flux lines 112 pass from the first winding 182 through the center of the magnetic core region and engage with the second winding 184. A good coupling pattern can be obtained by interleaving the first winding 182 and the second winding 184, as shown in Figs. Further, each of the windings 182 and 184 has a spiral shape to maintain a balanced transfer constructure and minimize the distance between the windings. In one embodiment, the winding is a straight spiral pattern with rounded corners.

(rectilinear spiral pattern) or a curved spiral pattern (curvilinear spiral pattern). FIG. 7A further shows plate 118 mounted on top of the first or second winding layer.

Furthermore, for this preferred embodiment according to the invention, the distance Y is chosen to be shorter than the distance X (FIG. 6B). The distance X (FIG. 6B) can range from 0.005 inches to 0.100 inches, for one preferred embodiment, can range from 0.006 inches to 0.050 inches, and for a further preferred embodiment, can range from 0.006 to 0.010 inches. . The distance Y, or the vertical space between any two adjacent windings, is set to be shorter than the distance X to optimize the electrical insulation and magnetic coupling properties. The closer the winding is, the greater the bond.

8A shows a plan view of a transformer layer 112 having a magnetic core region 114 formed by winding 120. 8B shows a cutaway view of the cross-sectional area of several layers of a multilayer transformer in accordance with a preferred embodiment of the present invention. In Fig. 8B, the first windings 158, 162 and the first windings 159 and 161, the second windings 160 and 164 and the second windings 161 and 165, the top plate 156 and the bottom plate 166 are shown, respectively.

FIG. 9 is an exploded view of a multilayer balanced transformer 132, with an end cap 124, a bottom cap 176, first winding layers 168, 170 with first windings 126 and 128, respectively; A second winding layer 172, 174 having two windings 178, 180 and a conductive via 130 are shown. In the preferred embodiment according to the invention, the first winding layers 168 and 170 are stacked on alternating adjacent layers. The first windings 126 and 128 are substantially arranged one on top of the other on each other. In a similar manner, second winding layers 172 and 174 are stacked on alternating adjacent layers. The second windings 178 and 180 are substantially arranged one on top of the other on each other. Further, the first windings 126 and 128 and the second windings 178 and 180 are arranged in an interleaving relationship on different layers and substantially aligned with each other to achieve optimum magnetic coupling within the multilayer transformer. Many other arrangements may exist for interleaving the first and second windings.
By way of example, Table 1 shows six different combinations that can be used to interleave the first and second windings, where the windings have different numbers of rotations. In Table 1, "P / x" represents the total number of 1st rotations, "S / x" represents the total number of 2nd rotations, and X is the total number of rotations of the said winding.

delete

Combination One 2 3 4 5 6 P / 1 S / 2 P / 2 S / 4 P / 4 S / 6 S / 1 P / 1 S / 1 P / 2 S / 2 P / 3 S / 2 P / 2 S / 2 P / 2 S / 3 P / 2 S / 2 P / 3 S / 4 P / 4 S / 3 P / 3 S / 6

To interleave the first and second windings, other various arrangements can be used.

10 is a plan view of transformer layer 116 showing a cutaway view of several cross-sectional areas of a multilayer transformer. 10 shows the inner core cross-sectional area 214, the two side regions 218 of the total top plate, the region of the conductive winding 220, and the outer cross-sectional area 222 of the layer 216. The cross-sectional area of the top plate covered by the flux line includes all four sides of the top plate area 218 (only two sides are visible).

The parameters shown in FIG. 10 determine the total inductance of the transformer. Inductance can be calculated using the following equation:

L = (0.4πN ² Aμ) / ℓ * 10 ⁸

Where N is the number of turns made by winding, A is the inner core cross-sectional area 214, μ is the magnetic permeability, and l is the length of the magnetic path. Total cross section of the multilayer transformer of the present invention The area is balanced to maximize the magnetic field for a given size of the transformer The balanced core cross-sectional area provides a balanced transformer, in which the flux line passes through the cross-sectional area of the plate and passes through the transformer layer, This is because the flux path is not limited in any direction when returning back through the core cross-sectional area.

In one preferred embodiment, the total cross-sectional area 218 of the plate covered by the magnetic flux includes all four sides, substantially the same as the magnetic core area 214 covered by the magnetic flux.

In another embodiment, all plate cross-sectional areas 218, covered by magnetic flux, include all four sides and are substantially larger than magnetic core areas 214 covered by magnetic flux.

11 A, B, and C are plan views of three different embodiments of a winding pattern according to a preferred embodiment of the present invention. The pattern is a straight spiral pattern 148, or a straight spiral pattern 150 having rounded corners 152, or a curved spiral pattern 154. The straight pattern 150 with rounded corners and the curved pattern 154 help to lower the trace capacitance by providing the required number of rotations while reducing all plate area of the spiral winding. Rounded edges or curved spirals also help to reduce the possibility of short circuits between two conductive portions of the winding during the manufacturing process.

As shown in FIGS. 1A and B, a conventional wound transformer has one long distinct core 42 (FIG. 1A) and a winding region 50 (FIG. 1B). This arrangement of windings relative to the core 42 (FIG. 1A) is difficult. In a preferred embodiment of the present invention, the above limitations limit the conductive windings 62, 72 (FIG. 5) of the multilayer ceramic transformer to the conductive vias 60 (FIGS. 2, 3, 4 and 5) and the central core regions 68, 69 (FIGS. 3, 4). By passing through), transformers can be obtained that are compact size, have good inductive coupling between windings, and meet safety regulatory requirements.

Transformers according to a preferred embodiment of the invention are manufactured using coheat ceramic technology. One example is to use low temperature-co-heat ceramic (LTCC) technology. As another example, high temperature-co-heating-ceramic (HTCC) technology is used. The core and electrical insulators are cast in tape form and are made of ferrite material. The tape is cut into sheet form, with a registration hole if necessary. Vias used as conductive interconnects between layers may be formed into holes in the ferrite tape using various techniques known in the art of ceramic hybrid circuit manufacturing. The vias are then conductive, such as silver (Ag), palladium-silver (PdAg), platinum-palladium-silver (PtPdAg) or other conductive materials, in the form of pastes or inks known and commonly used in the field of hybrid circuit manufacturing. By filling the hole with the material, it becomes conductive. Similar conductive elements or compounds are used to deposit conductive transformer windings on ferrite tape. As such, the conductive via is terminated and electrically connected to the winding. Vias and windings may be located in the central core region of the transformer layer. Individual ferrite tape layers, including filled vias and deposited conductive winding patterns, are stacked in proper alignment on other layers with vias to ensure electrical connectivity between the various layers in the formation of a multilayer transformer structure, as shown in FIG. . The collated layers may then be fused with each other under conditions such as heat and pressure, and subsequently heated to a homogenous monolithic structure by heating the entire structure in a furnace.

(monolithic) to form a ferrite multilayer transformer. The heating temperature may range from 1300 ° C. to 800 ° C. In one preferred embodiment, the heating temperature is from 1000 ° C. to 1200 ° C. and more preferably approximately 1100 ° C.

Using the procedure disclosed herein, multiple transformers can be produced simultaneously by producing large quantities of multilayer transformers by forming large arrays of vias and conductive windings on sheets of ferrite material. Individual transformers can be individualized before or after heating in a furnace.

Of course, those skilled in the art can make modifications to the methods and arrangements without departing from the spirit of the invention.

Preferred examples of the invention described above are provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. The scope of the present invention is not limited by this specification, but is defined by the following claims.

Claims (28)

A plurality of layers defining a magnetic core area disposed over two or more layers forming a magnetic core of the transformer; A first winding disposed on one or more layers and defining a central core region on the one or more layers; A second winding disposed on one or more layers and defining a central core region on the one or more layers; A plurality of first interconnect vias connecting the first windings between the layers; And, A plurality of second interconnecting vias connecting the second windings between the layers, wherein the first and second interconnecting vias are in a central core region defined by the first and second windings of the magnetic core of the transformer. Placed Transformer with a multi-layer tape structure. The transformer according to claim 1, wherein said layers are made of a coheat ceramic material. 3. The transformer of claim 2, wherein the coheat ceramic material is a Low Temperature Cofired Ceramic (LTCC) material. 3. The transformer of claim 2, wherein the coheat ceramic material is a High Temperature Cofired Ceramic (HTCC) material. A plurality of layers defining magnetic core regions disposed on at least two layers forming magnetic cores of the transformer; A first winding disposed on the first layer and defining a central core region on the first layer; A second winding disposed on the second layer, the second winding defining a central core region on the second layer; At this time, the first and second layers are disposed adjacent to each other, the first winding and the second winding, the multi-layer transformer is arranged in an interleaving relationship, from one layer to another layer. 6. The apparatus of claim 5, further comprising: a plurality of first interconnect vias connecting the first windings between layers; And, And a plurality of second interconnecting vias connecting the second windings between the layers. 7. The multilayer transformer of claim 6, wherein the first and second interconnect vias are disposed in a central core region defined by the first and second windings of the magnetic core of the transformer. 6. The multilayer transformer according to claim 5, wherein the start and finish ends of the first winding are disposed on the same layer of the plurality of layers of the transformer. 6. The multilayer transformer according to claim 5, wherein the start and finish ends of the second winding are disposed on the same layer of the plurality of layers of the transformer. 6. The multilayer transformer according to claim 5, wherein the start and finish ends of the first and second windings are disposed on the same layer of the plurality of layers of the transformer. 6. The ferromagnetic co-heated ceramic tape of claim 5, wherein the plurality of layers (ferromagnetic cofired ceramic tape). 12. The multilayer transformer of claim 11, wherein the ferromagnetic co-heat ceramic tape is made of low temperature co-heat ceramic (LTCC) material. 12. The multilayer transformer of claim 11, wherein the ferromagnetic co-heat ceramic tape is made of high temperature co-heat ceramic material (HTCC). 6. The multilayer transformer of claim 5, wherein the interleaved first and second windings are substantially aligned one on top of the other on each other. The first and second windings of claim 5, wherein the first and second windings are arranged in at least the first and second layers, respectively, in a magnetic core, wherein the first conductive member on the first layer is A terminal connected between the first and second layers via the via to the end of the second conductive member on the second layer, wherein the first and second layers are adjacent to each other, and the conductive member is a magnetic flux line of the magnetic core. a portion of the first conductive member perpendicular to the flux line and disposed in the central core region defined by the first winding is parallel to a portion of the second conductive member disposed in the central core region defined by the second winding, Wherein the two portions conduct substantially the same current in opposite directions and generate approximately the same magnetic field with opposite polarities, thereby substantially eliminating the net magnetic field around the via. Multilayer Accumulator. 6. The method of claim 5, wherein the first and second windings disposed in adjacent layers are spaced apart by a first distance, less than a second distance, which is the distance between two adjacent portions of the first conductive member of the first winding on the same layer. Multilayer transformer characterized in that. 6. The method of claim 5, wherein the first and second windings disposed in adjacent layers are spaced apart by a first distance, less than a second distance, which is the distance between two adjacent portions of the second conductive member of the second winding on the same layer. Multilayer transformer characterized in that.  6. The first and second windings of claim 5 disposed in adjacent layers by a first distance less than a second distance, which is an interval distance between the first and second conductive members of the first and second windings, respectively. Multilayer transformer, characterized in that apart. 6. The multi-layer transformer according to claim 5, wherein the first winding has a spiral shape. The multilayer transformer according to claim 5, wherein the second winding has a spiral shape.  16. The apparatus of claim 15, wherein at least the first winding disposed on the first layer generates a first magnetic flux; And, And the second winding disposed on at least the second layer is coupled with the first winding by the first magnetic flux. One or more layers; A winding disposed in at least one layer of said at least one layer and generating magnetic flux; An inner magnetic area formed by the winding and perpendicular to the magnetic flux; And, A plate disposed on top of the at least one layer of the at least one layer, the plate providing a return path for the magnetic flux through a cross-sectional area of the plate, wherein The cross-sectional area of the plate covered by is equal to the inner magnetic core area covered by magnetic flux, and the one or more layers are all formed of one material. One or more layers; A winding disposed in at least one layer of said at least one layer and generating magnetic flux; An inner magnetic core region formed by the winding and perpendicular to the magnetic flux; And, A plate disposed on top of the at least one layer of the at least one layer, the plate providing a return path for the magnetic flux through a plate cross-sectional area, wherein the cross-sectional area of the plate covered by the magnetic flux is covered by the magnetic flux. A balanced multilayer transformer that is greater than the inner magnetic core region and wherein the one or more layers are all formed of one material.  Nickel-copper-zinc-ferrite (NiCuZnFeO) having a ferrite (FeO) content of 40 to 60% by weight; Bismuth (Bi) in an amount of 1% or less by total weight; A ferromagnetic material for a ceramic transformer comprising zinc oxide (ZnO) in an amount of up to 10% of the total weight, wherein after heating the ceramic transformer, the zinc oxide particle size is 10 μm or less. 23. The balanced multilayer transformer of claim 22, wherein the one or more layers are all formed of ferromagnetic material. 27. The method of claim 25, wherein the ferromagnetic material  Nickel-copper-zinc-ferrite (NiCuZnFeO) having a ferrite (FeO) content of 40 to 60% by weight; Bismuth (Bi) in an amount of 1% or less by total weight; And A zinc oxide (ZnO) in an amount of up to 10% of the total weight, wherein, after heating a ceramic transformer, the zinc oxide particle size is 10 μm or less. 24. The balanced multilayer transformer of claim 23, wherein the one or more layers are all formed of ferromagnetic material. 28. The method of claim 27, wherein the ferromagnetic material  Nickel-copper-zinc-ferrite (NiCuZnFeO) having a ferrite (FeO) content of 40 to 60% by weight; Bismuth (Bi) in an amount of 1% or less by total weight; And A zinc oxide (ZnO) in an amount of up to 10% of the total weight, wherein, after heating a ceramic transformer, the zinc oxide particle size is 10 μm or less.

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