CA1177127A - Miniaturized transformer construction - Google Patents

Miniaturized transformer construction

Info

Publication number
CA1177127A
CA1177127A CA000388362A CA388362A CA1177127A CA 1177127 A CA1177127 A CA 1177127A CA 000388362 A CA000388362 A CA 000388362A CA 388362 A CA388362 A CA 388362A CA 1177127 A CA1177127 A CA 1177127A
Authority
CA
Canada
Prior art keywords
windings
means
dielectric
substrates
spiral
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA000388362A
Other languages
French (fr)
Inventor
William H. Morong, Iii
Delip R. Bokil
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Analog Devices Inc
Original Assignee
Analog Devices Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US20683880A priority Critical
Priority to US206,838 priority
Application filed by Analog Devices Inc filed Critical Analog Devices Inc
Application granted granted Critical
Publication of CA1177127A publication Critical patent/CA1177127A/en
Application status is Expired legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/28Coils; Windings; Conductive connections
    • H01F27/2804Printed windings
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00Fixed transformers or mutual inductances of the signal type
    • H01F19/04Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/08Transformers having magnetic bias, e.g. for handling pulses
    • H01F2019/085Transformer for galvanic isolation
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00Details of transformers or inductances, in general
    • H01F27/28Coils; Windings; Conductive connections
    • H01F27/2804Printed windings
    • H01F2027/2819Planar transformers with printed windings, e.g. surrounded by two cores and to be mounted on printed circuit
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/02Details
    • H05K1/09Use of materials for the conductive, e.g. metallic pattern
    • H05K1/092Dispersed materials, e.g. conductive pastes or inks
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00Printed circuits
    • H05K1/16Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
    • H05K1/165Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed inductors
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05KPRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00Apparatus or processes for manufacturing printed circuits
    • H05K3/46Manufacturing multilayer circuits
    • H05K3/4644Manufacturing multilayer circuits by building the multilayer layer by layer, i.e. build-up multilayer circuits
    • H05K3/4664Adding a circuit layer by thick film methods, e.g. printing techniques or by other techniques for making conductive patterns by using pastes, inks or powders

Abstract

ABSTRACT OF THE DISCLOSURE

A miniaturized transformer comprising two rectangular substrates each carrying successive screen-printed thick-film layers of dielectric with spiral planar windings embedded therein.
The substrates and the dielectric layers are formed with a cen-tral opening in which is positioned the central leg of a three-legged solid magnetic core. The remaining portions of the core surround the two substrates to form a compact rugged construction especially suitable for assembly with hybrid integrated circuit components.

Description

935.050 ~7'7~27 BACKGROUND OF THE INVENTION

Field of the Invention This invention relates to transformers. More particular-ly, this invention relates to miniaturized transformers suitable for use in small-sized electrical devices such as hybrid integrated circuit components, or small-sized modular components.

Description of the Prior Art As demand for small-sized electrical components has ; increased over the years, there has been a corresponding need to provide miniaturized transformers for components requiring such elements. Generally speaking, the problem of transformer minia~
turization has been quite difficult relative to miniaturization of other kinds of electrical elements, and this has particularly been true where low~frequency applications are involved.

For a number of reasons, traditional transformer design concepts have not provided a suitable basis for making such minia-turized transformers. For example, conventional wound transformers are difficult to make in small sizes, especially because the wind-ings typically must be made of very tiny wire. The cost of manu-facture also is considerable, due to the large amount of painstaking labor required. Moreover, it has been difficult to achieve high performance with such small-sized devices of conventional design.

-2-935.050 Various proposals have been made from time to time seeking a solution to the problem of making minaturized trans-formers, but none of these proposals has resulted in a truly satisfactory transformer construction.

SUMMARY OF THE INVE~TION

In a preferred embodiment of the present invention to be described hereinafter in detail, a compact transformer con-struction is provided wherein the transformer windings are arranged in planar spiral configuration, with each winding embedded in a layer of solid insulating dielectric securely attached to a rigid substrate Both the substrate and the in-sulating dielectric are formed with a common opening about which the windings are disposed, and a solid magnetic core extends through that opening to form a low-reluctance closed magnetic circuit for the transformer windings. Advantageously, a trans-former in accordance with this invention may comprise two such rigid substrates carrying identical sets of planar spiral wind-ings disposed about the common solid magnetic core.

The layers of insulating dielectric and windings em-bedded therein preferably are laid down on the substrate by well-established thick film deposition processes. It thus is possible to ma~e, at low cost, a rugged multi-layered transformer structure combining small size, excellent performance, high relia-bility, and ready adaptability to standard component assembly techniques.

935.050 ~L77~27 Accordingly, it is an object of the present invention to provide a superior transformer of small size. ~nother object of the invention is to provide such a transformer which is capable of economical manufacture and suitable for standard assembly techniques. Yet another object of the invention is to provide such a transformer which can be used for low-frequency applications and which has high performance capa~lities including excellent magnetic coupling, good linearity, and the ability to withstand ; high voltages between windings. Still other objects, aspects and advantages of the invention will in part be pointed out in, and in part apparent from, the following detailed description of a preferred embodiment of the invention, considered together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWI~GS

.
FIGURE 1 is a plan view of a transformer constructed in accordance with the present invention. (~ote: The opaque layers of insulating dielectric are not shown in this view in order to present the general configuration of the metalliæed windings embed-ded in the dielectric.);

FIGURE 2 is a side elevation view of the transformer shown in Figure l;

FIGURE 3 is a vertical section taken along line 3-3 of Figure l;

935.050 7~31 27 FIGURE 4 is an enlarged plan view of one substrate of the transformer, showing -the three transformer windings as though the insulating dielectric were transparent;

FIGURE 5 is a detail section taken along line 5-5 of Figure 4; and FIGURE 6 is a detail section taken along line 6-6 of Figure 4.

'DETAILED DESCRIPTIO~ OF A PREFERRED EMBODIMENT

: Referring now to Figures 1-3, the transformer in accord-ance with the present invention comprises first and second rigid -~_~
rectangular substrates 10 and 12 of alumina, held together in over-lying posltion, and offset a short distance longitudinally. Each substrate carries on one flat surface thereof a film as generally . indicated at 14 and 16. These films comprise a series of distinct layers of an insulating dielectric, with each layer having embedded therein a corresponding planar spiral winding in the form generally illustrated at 18 in Figure l. In the present embodiment, each of the two substrates lO and 12 carries -three such winding layers, for a total-of six transformer windings.

935.050 71;~7 The multi-layered films 14 and 16 preferably are formed by well-known thick-film processing techniques. In one such process, each individual winding layer of the film is developed by screen-printing a metallization pattern, comprising a matrix of conduc-tive particles arranged (in this case) in a spiral configuration, and an overlay of insulating dielectric material such as a high-temperature crystallizable glass dielectric. The screen-printed material then is either singly or co-fired at high temperature to complete the process.

Firing of the screen-printed material causes the con-ductive particles of the metallization pattern to be sintered and fused into a continuous conductor forming a planar spiral winding such as is generally indicated at 18 in Figure 1. E'iring also solidifies the glass insulating dielectric to form a rigid 15 pancake-like structure with the planar spiral winding embedded ~__ therein.

As noted above, each substrate 10, 12 carries three such ; winding layers. As will be described in more detail hereinbelow, a fourth layer also is laid over the top winding layer to provide cross-over electrical conductors for making connections from the inner ends of the three windings to corresponding termination points at the edge of each substrate. The screen-printing and firing procedure is carried out for each winding layer, and also for the fourth layer establishing the cross-over electrical connections.
Each of the four screen-printed layers ordinarily will be about 935.050 ~L1773~:7 1 mil thick (0.001"), whereas the supporting alumina substrate may have a thickness of about .015".

The central portions of the substrates 10, 12 are enclosed within a three-legged magnetic core 20, preferably composed of facing, mated E-I cores adhesively secured together at the regions of joinder. These E-I cores are asse~led to the completed sub-strates with the central leg 22 of the E-core fitted into aligned rectangular holes 24 (see also Figure 4) cut in the substrates prior to the thick-film processing. The side legs 26, 28 of the E-core extend down along the sides of the substrates to the regions of joinder with the flat I-core, to establish closed magnetic circuits passing through the substrate openings 24.

The screen-printed films 14, 16 applied to the substrates 10, 12 extend substantially to the edges of the central openings 24 cut in the substrates. The magnetic core leg 22 is dimensioned to provide a reasonably close fit with the openings 24, and serves to aid in holding the substrates in position.

As shown in Figure 1, each substrate 10, 12 is provided at one end thereof with a set of termination pads 30, 32 for making electrical connections to the spiral windings generally indicated at 18. With the longitudinally offset arrangement of the substrates, both termination pads, 30, 32 are readily accessible from the same side of the transformer for establishing connections thereto.

~7~

It will be seen that the transformer of this invention is especially suitable for adap-ta-tion -to hybrid in-tegrated cir-cuit components, and can readily be mounted on a mother substrate together with o-ther elemen-ts. Conventional connection techniques such as wire-bonding advantageously can be used to make electrical connection to the termination pads 30, 32. As noted above, each subs-trate in the present embodiment carries three separa-te wind-ings (in corresponding layers of -the -thick films 14, 16) requi-ing six -terminals on each substrate. Such a transformer is particularly adap-ted for use in a single--transformer isola-tor of the type disclosed in copending Canadian Paten-t Application No.
367,616, filed on December 29, 1980 by Analog Devices, Incorporated assignee of William H. Morong, III.

In this embodiment, bo-th subs-trates 10 and 12 are identical, with essentially identical mul-ti-layered films 14 and 16 containing the sets of three spiral -transformer windings.
Since the winding arrangemen-ts are essen-tially iden-tical, only one set of windings will be described hereinbelow.

Referring now -to the plan view of Figure 4 and the sec--tional views of Figures 5 and 6, i-t can be seen that the spiral conductors of each of the three windings 34, 36, 38 are planar, with adjacent turns of the spiral being uniformly spaced apart.
The conductors of -the bot-tom and -top windings 34, 38 are aligned vertically, while the conductors of -the middle winding are offset laterally from -those of the other two windings, -to assure optimum spacing. Insulating dielectric 40 is laid down for each layer 935.050 ineluding the fourth layer 42 for the eross-over eonductors.
The dieleetrie material extends between and around -the metal-lization layers, and includes an outer layer 40a.

Referring partieularly to Figures 4 and 6, the fourth thick-film layer 42 comprises a set of cross-over return con-ductors such as the conduetor illustrated at 44. That eross-over eonduetor is eonneeted at its inner end 44a to the inner end of the eorresponding spiral winding 36 by means of a vertical con-ductor 46. This conductor is formed in staircase fashion by a series of metallizations earried out during formation of the winding layers 34, 36, 38. Sueh vertical stairease eonduetor is loeated in a eorresponding reetangular vertieal opening 50 (Figure 4) formed in the insulating dieleetrie 40 during sereen-printing of the winding layers. The outer end 44b of the eross-over conduetor 44 is eonnected to the corresponding -terminal ~__ point 52 of the termination pad 26 by means of a vertical conauc-tor 54 which also is formed in stairease fashion by a series of metallizations, just as in making the inner vertieal conductor 46.

The formation of the multiple winding layers as described above, including the vertieal eonduetors 46 and 54, is earried out using well-known and frequently used multi-layer thiek-film tech-niques which are part of the established prior art in that area of technology. Thus detailed diseussion of these techniques has been omitted, in order to simplify the present diselosure.

935.050 ~7~

Although a specific preferred embodiment of the novel transformer construction of the present invention has been de-scribed hereinabove in detail, it is desired to emphasize that this detailed description is solely for the purpose of illus-trating the invention, and is not to be considered as limitingthe scope of the invention since it is clear that many variations and modifications can be made by those of skill in the art in order to meet the requirements of particular applications. For example, transformers in accordance with the invention can be provided with different numbers of windings, and various kinds of conductive materials and techniques can be used to form the wind-ings. Different types of insulating dielectric can be employed.
Also, although the described arrangement provides a single winding in each layer, other arrangements are possible. For example, each of two layers could carry one-half of a spiral windlng, with ~__ the complete winding being established by making vertical connec-tion between the inner ends of the two half-windings. Additionally, each layer could be formed with more than a single winding (or half-winding) by using spiral interlace arrangements. Thus it is clear that there are many ways in which to carry out the inven-tion to obtain the important advantages thereof.

Claims (15)

CLAIMS:
1. A transformer comprising:
first and second winding means each including at least one spiral turn disposed about a central region;
said spiral turns being generally planar with the planes thereof parallel;
said winding means being embedded in rigid insulating dielectric means-of generally flat configuration with the lateral dimensions thereof parallel to said planar winding means;
substrate means supporting said dielectric insulation means;
said substrate means and said insulating dielectric means being formed with an opening therethrough centrally located to correspond to said central region of said spiral winding means;
a solid magnetic core extending through said opening and linking both said first and second winding means; and termination means connected to the ends of said winding means to provide for making electrical connection thereto.
2. Apparatus as in Claim 1, wherein said winding means comprises a matrix of conductive particles within said dielectric means and fired at high temperature so that said conductive parti-cles are sintered together to form continuous conductors for said winding means.
3. Apparatus in Claim 1, wherein said insulating dielec-tric means comprises at least first and second adjacent layers on a single substrate, each such layer having embedded therein a corresponding spiral winding.
4. Apparatus as in Claim 3, including a further layer of insulating dielectric providing cross-over conductors for making connection to the inner ends of at least one of said windings.
5. Apparatus as in Claim 1, wherein said magnetic core is a three-legged structure with the center leg thereof passing through said opening and the remainder of the core surrounding said substrate means.
6. Apparatus as in Claim 5, wherein said magnetic core comprises mated E-I cores.
7. Apparatus as in Claim 1, wherein said substrate means comprises first and second substrates each carrying at least one layer of insulating dielectric with a spiral winding embedded therein.
8. Apparatus as in Claim 7, wherein each of said first and second substrates includes a plurality of layers of dielectric with planar spiral windings embedded therein.
9. Apparatus as in Claim 7, wherein said magnetic core is a three-legged structure with the center leg thereof passing through said opening;
said two substrates being secured together in parallel closely-adjacent positions passing through the spaces between said center leg and the outer legs of said core structure.
10. Apparatus as in Claim 7, wherein said substrates are elongate members secured together in parallel overlying relation-ship, offset a short distance longitudinally;
said substrates being provided at opposite ends thereof with termination means accessible from the same side as a result of said longitudinal offset.
11. A transformer comprising:
first and second substrates secured together in parallel configuration;
each of said substrates carrying at least one layer of insulating dielectric surrounding a corresponding winding in the form of a spiral conductor;
said spiral windings being positioned so that the central regions thereof are vertically aligned;
said layers of insulating dielectric and said substrates all being formed with a common opening passing therethrough in a direction perpendicular to the planes of said substrates and through said central regions of both of said spiral windings;
a solid magnetic core extending through said opening to link both said first and second windings; and termination means connected to the ends of said winding means to provide for making electrical connection thereto.
12. A screened thick-film transformer of very small size for use with hybrid circuit boards and the like, comprising:
a rigid non-magnetic substrate:
first and second multi-turn spiral windings formed in separate layers of dielectric material supported one above the other by said substrate in generally aligned configuration and each disposed about a common central region;
said spiral windings being generally planar with the planes thereof parallel;
said first and second windings each comprising con-ductors formed of fused conductive particles embedded within a layer of dielectric insulating material solidified by firing at high temperature to form a rigid structure with said windings hermetically sealed therein and conductively isolated from each other by said dielectric insulating material within the trans-former; :
said substrate and said dielectric insulating material having a central opening therethrough corresponding to said common central region of said spiral windings;
a magnetic core extending through said opening forming a low reluctance closed magnetic circuit for said first and second windings of said transformer;
said substrate being formed at one end with two pairs of closely adjacent connection pads all located at a single level to accommodate automated connection making; and conductors formed of fused conductive particles estab-lishing connections between said first and second windings and said pairs of connection pads, respectively.
13. A miniature transformer for use with hybrid circuit boards and the like, comprising:
first and second rigid non-magnetic substrates arranged one above the other in parallel disposition;
first and second multi-turn spiral windings sup-ported by said substrates respectively and each disposed about a central region;
said spiral windings being generally planar with the planes thereof parallel and located on one side of the corresponding substrate to provide that the windings are non-contiguous and spaced apart by at least one of said substrates;
said first and second windings each comprising con-ductors formed of fused conductive particles embedded within a layer of dielectric insulating means solidified by firing at high temperature to form a rigid structure with said wind-ings hermetically sealed therein;
both of said substrates and said dielectric insulat-ing means having aligned central openings therethrough corre-sponding to said central regions of said spiral windings;
a solid magnetic core extending through said opening forming a closed magnetic circuit for said transformer;
said magnetic core comprising two separate pre-formed portions establishing a closed magnetic path completely encir-cling said first and second non-magnetic substrates; and termination means connected to the ends of said first and second windings respectively to provide separate electrical connections thereto.
14. The method of making a miniaturized transformer comprising the steps of:
supporting on rigid non-magnetic substrate means a first metallization pattern in the form of a matrix of con-ductive particles arranged in a multi-turn planar spiral winding configuration about a central opening in the sub-strate means;
applying a first overlay of high-temperature firable dielectric insulating material to cover said first metalliza-tion pattern;
supporting on said substrate means a second metal-lization pattern in the form of a matrix of conductive particles arranged in a multi-turn planar spiral winding configuration about the central opening of said substrate means; said second winding being essentially coextensive with said first winding and conductively isolated therefrom;
applying a second overlay of high-temperature firable dielectric insulating material to cover said second metalliza-tion pattern;
firing said conductive particles and said dielectric material at a high temperature to fuse said conductive par-ticles into continuous conductors forming separate planar windings and to solidify said insulating dielectric material to form rigid pancake-like structures with said windings embedded and hermetically sealed therein;
placing in said central opening a pre-formed solid magnetic core having a return path completely surrounding said substrate means; and establishing two pairs of connections to the ends of said two windings, respectively, with one connection of each pair extending across the corresponding winding to the interior region adjacent said central opening.
15. A screened thick-film transformer of very small size adapted for use with hybrid circuit boards and the like, comprising:
rigid non-magnetic substrate means;
first and second multi-turn spiral windings sup-ported one above the other by said substrate means in generally aligned configuration and each disposed about a common central region;
said spiral windings being generally planar with the planes thereof parallel and vertically offset;
said first and second windings each comprising con-ductors formed of fused conductive particles embedded within a layer of dielectric insulating means solidified by firing at high temperature to form a rigid structure with said windings hermetically sealed therein and conductively isolated from each other within the transformer;
said substrate means and said dielectric insulating means having a central opening therethrough corresponding to said common central region of said spiral windings;
a magnetic core extending through said opening to form a low-reluctance closed magnetic circuit through said first and second windings;
said substrate means being formed with connection pads;
conductors formed of fused conductive particles establishing connections between said firs-t and second windings and said connection pads.
CA000388362A 1980-11-14 1981-10-20 Miniaturized transformer construction Expired CA1177127A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US20683880A true 1980-11-14 1980-11-14
US206,838 1980-11-14

Publications (1)

Publication Number Publication Date
CA1177127A true CA1177127A (en) 1984-10-30

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ID=22768186

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000388362A Expired CA1177127A (en) 1980-11-14 1981-10-20 Miniaturized transformer construction

Country Status (6)

Country Link
JP (1) JPS57111008A (en)
CA (1) CA1177127A (en)
DE (1) DE3144026A1 (en)
FR (1) FR2494490B1 (en)
GB (1) GB2087656B (en)
NL (1) NL8105144A (en)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6174311A (en) * 1984-09-20 1986-04-16 Kangiyou Denki Kiki Kk Transformer having coil formed of superposed wiring body
JPS6175510A (en) * 1984-09-21 1986-04-17 Kangiyou Denki Kiki Kk Small sized transformer
US4692604A (en) * 1984-10-25 1987-09-08 American Telephone And Telegraph Company, At&T Bell Laboratories Flexible inductor
JPS6176939U (en) * 1984-10-26 1986-05-23
GB2173956B (en) * 1985-03-29 1989-01-05 Plessey Co Plc Improvements relating to electric transformers
JPH0624985Y2 (en) * 1985-09-06 1994-06-29 株式会社ト−キン Thin transformer
JPH01205509A (en) * 1987-12-02 1989-08-17 John Fluke Mfg Co Inc High frequency electric power transformer
JPH0289302A (en) * 1988-09-27 1990-03-29 Matsushita Electric Ind Co Ltd Coil
JPH0289301A (en) * 1988-09-27 1990-03-29 Matsushita Electric Ind Co Ltd Coil
DE69011755D1 (en) * 1989-06-16 1994-09-29 Matsushita Electric Ind Co Ltd Manufacturing method of a thin film coil with a multi-part winding.
DE9114783U1 (en) * 1990-03-30 1992-03-19 Multisource Technology Corp., Waltham, Mass., Us
DE4117878C2 (en) 1990-05-31 1996-09-26 Toshiba Kawasaki Kk Planar magnetic element
GB2252208B (en) * 1991-01-24 1995-05-03 Burr Brown Corp Hybrid integrated circuit planar transformer
JP3141562B2 (en) * 1992-05-27 2001-03-05 富士電機株式会社 Thin film transformer device
DE4244107C2 (en) * 1992-12-24 1996-02-08 Hirschmann Richard Gmbh Co High-frequency transformer
TW436823B (en) * 1994-06-29 2001-05-28 Yokogawa Electric Corp Prited coil type transformer
US5754088A (en) * 1994-11-17 1998-05-19 International Business Machines Corporation Planar transformer and method of manufacture
GB9424349D0 (en) 1994-12-02 1995-01-18 Measurement Tech Ltd Transformers
DE19853510A1 (en) * 1998-11-20 2000-05-25 Thomson Brandt Gmbh Line filter
DE60137058D1 (en) * 2000-09-20 2009-01-29 Det Int Holding Ltd Planar inductive element

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3431144A (en) * 1963-12-26 1969-03-04 Nippon Electric Co Method for manufacturing microminiature coils
US3483499A (en) * 1968-08-08 1969-12-09 Bourns Inc Inductive device
US3772587A (en) * 1972-03-15 1973-11-13 Inductosyn Corp Position measuring transformer
JPS622733Y2 (en) * 1978-09-11 1987-01-22

Also Published As

Publication number Publication date
GB2087656A (en) 1982-05-26
JPS57111008A (en) 1982-07-10
DE3144026A1 (en) 1982-06-24
FR2494490B1 (en) 1985-01-18
GB2087656B (en) 1983-09-28
CA1177127A1 (en)
NL8105144A (en) 1982-06-01
FR2494490A1 (en) 1982-05-21

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