GB2285892A - Transformer structurally combined with an electrical/electronic circuit substrate - Google Patents
Transformer structurally combined with an electrical/electronic circuit substrate Download PDFInfo
- Publication number
- GB2285892A GB2285892A GB9400204A GB9400204A GB2285892A GB 2285892 A GB2285892 A GB 2285892A GB 9400204 A GB9400204 A GB 9400204A GB 9400204 A GB9400204 A GB 9400204A GB 2285892 A GB2285892 A GB 2285892A
- Authority
- GB
- United Kingdom
- Prior art keywords
- winding
- transformer assembly
- assembly according
- apertures
- substrate
- 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.)
- Granted
Links
- 239000000758 substrate Substances 0.000 title claims description 23
- 238000004804 winding Methods 0.000 claims abstract description 99
- 230000004907 flux Effects 0.000 claims abstract description 26
- 238000000926 separation method Methods 0.000 claims description 8
- 229910010293 ceramic material Inorganic materials 0.000 claims description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 10
- 229910052802 copper Inorganic materials 0.000 abstract description 10
- 239000010949 copper Substances 0.000 abstract description 10
- IYZWUWBAFUBNCH-UHFFFAOYSA-N 2,6-dichlorobiphenyl Chemical compound ClC1=CC=CC(Cl)=C1C1=CC=CC=C1 IYZWUWBAFUBNCH-UHFFFAOYSA-N 0.000 description 18
- 239000000463 material Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000003475 lamination Methods 0.000 description 2
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003467 diminishing effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/0006—Printed inductances
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F19/00—Fixed transformers or mutual inductances of the signal type
- H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2847—Sheets; Strips
- H01F2027/2861—Coil formed by folding a blank
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Multimedia (AREA)
- Coils Or Transformers For Communication (AREA)
- Coils Of Transformers For General Uses (AREA)
Abstract
A transformer assembly comprises a core (101) and secondary and primary windings. The secondary winding is incorporated on a printed circuit board (10) onto which is also provided the electrical or electronic circuit. The primary winding is provided as a separate winding, adjacent the printed circuit board, on an auxiliary printed circuit board (113). The windings are formed as helically wound copper tracks around apertures formed in the printed circuit board. Fractional turns may be provided in the windings, if required. Flux balancing windings (116) may also be provided to ensure that more flux is not drawn from one part of the core than another. A stepped gap (27) may be provided in a central core portion 17 to enable the transformer assembly to run at both high and low loads. <IMAGE>
Description
A TRANSFORMER ASSEMBLY
This invention relates to a transformer assembly, in particular,although not exclusively,for use in electrical and electronic circuits.
Transformers used in electrical and electronic applications for "transforming" an input voltage to a higher or lower output voltage are,in themselves,well known to persons skilled in the art.
A typical,known,transformer is illustrated schematically in
Figure 2.Such a transformer comprises a laminated core l.The core 1 may comprise,for example,a generally E-shaped lamination 2 and a flat plate lamination 3.Wound around the central limb 4 of the core 1 is a primary coil or winding 5,usually of copper,to which an input voltage is applied via a connection 6.When an input voltage is applied to the primary winding 5,an output voltage is induced in a secondary coil or winding 7,also usually of copper,wound around the primary winding 5.This induced voltage is supplied as an output voltage via a second connection 8.The ratio of the input voltage to the output voltage is dependant upon the ratio of the turns in the primary and secondary windings 5,7,and is roughly equal to that ratio.Thus a transformer with 2000 turns on the primary winding 5 and 1000 turns on the secondary winding 7 will have an output voltage which is approximately half that of the input voltage.The laminated core 1 is made of,for example,a ferromagnetic material e.g.silicon steel.As already mentioned,transformers are already well known to persons skilled in the art,and,as such,their various constructions and operation need not be described herein in any greater detail.
Transformers have many applications in electrical and electronic circuit design,for example,for reducing the voltage of an alternating current (AC) mains power supply to a lower level more suitable for the electronic circuitry.
In the design of electrical and electronic apparatus,designers often make extensive use of printed circuit boards (PCB's) for the electronic circuitry.The use and manufacture of PCB's is well known to persons skilled in the art,and,as such,need not be described in detail herein.
Where transformers are used in electronic circuitry,because of the relatively large size of the transformers,constraints are put on the design of the electronic circuitry,and,in particular,on the compactness of the design of any apparatus incorporating this circuitry that can be achieved.
According to the present invention,there is provided a transformer assembly for an electrical or electronic circuit provided on a substrate,the assembly comprising a first winding,and a second winding electromagnetically coupled to the first winding wherein at least the first winding is provided on the substrate.This has the advantage that,because the second winding is formed on the substrate,a more compact transformer assembly,and,therefore,a more compact apparatus utilising such atransformer assembly,can be achieved.
The substrate may be a PCB,or a thermally conducting substrate,for example of a ceramic material.
The first winding may be wound in a helical configuration,for a predetermined number of turns,in the plane of the substrate.The substrate may be provided with at least one aperture formed therein,and the first winding may be configured to run around the at least one aperture,starting at a point adjacent the aperture and running helically outwards to a suitable termination point on the substrate.
The substrate may be provided with at least one pair of apertures having a columnar arrangement with a separation therebetween.
In order to produce the correct output voltage for a given input voltage,partial turns e.g a quarter or a half turn,may be required.The first winding may be configured to run,from the starting point,through the separation and around one of the apertures of the at least one pair of apertures to form a fractional turn.
The assembly may further comprise a transformer core in which first and second core portions of the core are received in the at least one pair of apertures respectively, such that the first winding is wound around the core portions.The transformer assembly may further comprise a flux balancing winding provided adjacent,and substantially parallel to,the first winding,the flux balancing winding having a figure-of-eight configuration such that one turn of the figure-of-eight is configured to run around each of the core portions when received in the respective apertures,so that equal amounts of flux are taken from each core portion when current flows in the first winding.This has the advantage that,because of the provision of this flux balancing winding,any attempt to draw more flux from one core portion resulting in the flux diminishing in that portion,and,consequently,giving the result that a fractional turn appears to have a smaller ratio,does not occur.
An embodiment of the invention will now be described,by way of example only,with reference to the accompanying drawings,of which:
Figure 1 is a simplified circuit diagram of a switch mode power supply incorporating a transformer assembly in accordance with the invention;
Figure 2 is a schematic vertical cross section of a transformer of the prior art;
Figure 3 is a horizontal cross section along the line III-III of
Figure 4,of a transformer assembly in accordance with the invention,as incorporated on a PCB;
Figure 4 is a vertical cross section along the line IV-IV of
Figure 3;
Figure 5 is an underside view of a substantially E-shaped core piece of a transformer assembly in accordance with the invention; and
Figures 6 and 7 illustrate the forming of a loose winding for a transformer assembly in accordance with the present invention.
Figure 1 is a simplified circuit diagram of a switch mode power supply incorporating a transformer assembly 100.Switch mode power supplies are,in themselves,well known,and,as such,need not be described in any greater detail herein.However,a brief description of the circuit diagram of Figure 1 will be given below as is relevant at the present invention.An input voltage
Vin is supplied,via a choke 108 coupled in series to two transformer primary windings 102,103.The two transformer primary windings 102,103 are driven by MOSFET's 109,110 by a control chip (not shown) in a known manner.The output voltages V1OUT and V20UT from two transformer secondary windings 104,105 respectively are controlled by the ON to OFF ratio of the MOSFET's 109,110,which is also dependant upon the load L and the input voltage Vin.The transformer primary windings 102,103 and the transformer secondary windings 104,105 form two transformer sections 106,107.The choke 108 comprises a choke primary winding 111 and a choke secondary winding 112.The choke 108 is used to substantially remove any ripple from the output and,as such,provision of a choke in transformers is already well known to persons skilled in the art.The choke windings 111,112 are in series with the transformer section windings 102,103,104,105.The choke secondary winding 112 conducts only when neither of the secondary windings 104,105 on the transformer sections 106,107 are conducting so that the choke 108 acts as an input and an output choke.
A printed circuit board (PCB) 10,onto which may be formed a required wiring pattern (not shown) for an electronic circuit,and onto which the required components for the circuit to which the transformer assembly 100 is to be coupled may be mounted, is provided,on an area of the PCB 10 where the transformer assembly 100 is to be located,with a rectangular array of six rectangular shaped apertures 11.The array comprises three pairs 24 of apertures 11,each pair 24 comprising a column of two of the apertures 11 with a separation 25 between each aperture 11 as seen in Figure 3.The mounting of components,and the provision of wiring patterns to electrically couple the components,on PCB's is well known to persons skilled in the art and, insofar as it is not relevant to the present invention need not be described any further herein.
A core 101 of the transformer assembly 100 comprises two substantially identical E-shaped core pieces 12,13.Each core piece 12,13 comprises a rectangular plate 14 having two outer limbs 15,16 at its outer edges,the limbs 15,16 extending substantially parallel to each other and substantially perpendicular from the same face of,and at the outer edges of,the plate 14.Each core piece 12,13 also has a central limb 17,extending,again from the same face as,and substantially parallel to,the two outer limbs 15,16.Thus,each core piece 12,13 is substantially E-shaped in cross section,as is shown clearly in Figure 3.
Each of the limbs 15,16,17 is split into two limb portions 15a;15b,16a;16b,17a;17b by respective spacings 18,19,20 as shown in Figure 3.The plate 14,the limbs 15,16,17 and the spacings 18,19,20 are dimensioned and arranged so that each limb portion 15a;15b,16a;16b.17a;17b can be received in respective one of the apertures 11 formed in the PCB 10 i.e so that each pair 24 of the apertures 11 receives a respective limb 15,16,17.In the embodiment described herein,the central limb 17 is substantially equidistant between the two outer limbs 15,16 and each spacing 18,19,20 is substantially centrally located in each limb 15,16,17.The apertures 11 on the PCB 10 are also shaped accordingly to receive the respective limb portions 15a;15b,16a;16b,17a;17b.
To form the core 101 of the transformer assembly 100,one core piece 12,13 is placed either side of the PCB 10,the limb portions 15a;15b,16a;16b,17a;17b being received in the respective apertures 11 as described above,with the PCB 10 sandwiched between the two core pieces 12,13.When the two core pieces 12,13 are in place,the limb portions 15a;15b,16a;16b,17a;17b of each core piece 12,13,when in contact with each other,define core portions which 15c;16c;17c located through the apertures 11 as shown in Figure 4.
The windings for the transformer assembly 100 are provided as described below.
Etched onto a layer,for example the outer surface,or on of the inner layers,of the PCB 10 around each pair 24 of apertures 11 is a helically wound copper track 21,22,23 starting at points 28,29,30 adjacent one of the apertures 11 of a pair 24 and running helically outward for an appropriate number of turns as required to provide the correct output voltage,from the pair 24 to terminate at a suitable point 31,32,33,on the PCB 10 to form the secondary windings 104,105,112 of the transformer assembly 100 respectively.The central core portion 17c and the winding 112 therearound form the core and the secondary winding for the choke 108,while the outer core portion 15c,16c and the respective secondary windings 104,105 therearound form the core and secondary windings of the transformer sections 106,107 respectively.
In order to provide some output voltages,the secondary windings 104,105,112 may be required to be fractional e.g half or quarter turns as described above.
In order to achieve a fractional,e.g half turn,the spacings 18,19,29 in the limbs 15,16,17 and the separations 25 in each pair 24 of apertures 11 are used.
To achieve the fractional turn (in this embodiment a half turn) the initial part of the relevant winding 104,105,112 is configured to run from the starting point 31,32,33 adjacent one of the apertures 11 of the relevant pair 24 of apertures around one of the limb portions 15a;15b,16a;16b,17a;17b only.This is effected by forming copper tracks 21,22,23 on the PCB 10 in the appropriate configurations around the apertures 11 and through the separations 25 as illustrated in Figure 3.In Figure 3 ,each winding 104,105,112 is shown to incorporate a half turn,although,depending upon the required output voltages,only one or two of the windings 104,105,112 may incorporate half turns,or,indeed,no fractional turns may be required.
When a fractional turn is provided,in order that the flux is balanced,a loose flux balancing winding 116 is provided for each secondary winding 104,105,112 which has a fractional turn.These are provided adjacent to and substantially parallel to the relevant secondary winding 104,105,112,as illustrated in Figure 4.
The flux balancing winding 116 is configured in a figure-of-eight shape i.e such that there is one turn of the flux balancing winding 116 around each core portion 15c,16c,17c of the core 101.It is formed on a flexible circuit board 118 using known manufacturing techniques.To form the flux balancing winding 116,a copper track 117 is etched onto the flexible circuit board material 118 around two laterally spaced apertures 119 of substantially the same shape and size as the apertures 11 formed in the PCB 10,as shown in Figures 6 and 7.The flexible circuit board 118 is then folded along the line X-X' of Figure 6 to form the figure-of-eight as shown in Figure 7.Suitable insulation 120,as is well known to persons skilled in the art,is provided where the copper track 117 overlaps after folding to prevent shorting.By incorporating this flux balancing winding 116,equal amounts of flux are taken from each of the core portions 15c,16c,17c so that each turn in the flux balancing winding 116 produces an equal but oppposing voltage with the result that no current flows around the Figure-of-eight.
The primary windings 102,103,111 for the transformer sections 106,107 and the choke 108 respectively are also provided by loose windings.The primary windings 102,103,111 are provided on an auxiliary printed circuit board 113 provided, as with the flux balancing winding 116,adjacent and substantially parallel to the
PCB 10.As with the secondary windings 104,105,112,the primary windings 102,103,111 are formed as helically wound copper tracks having the appropriate number of turns,having regard to the number of turns in the secondary windings 104,105,112, to provide the correct output voltage for a given input voltage,in a similar manner to the secondary windings 104,105,112.Each of the copper tracks forming the primary windings 102,103,111 are configured around pairs of apertures in the auxiliary printed circuit board 113,such that,when the auxiliary printed circuit board 113 is mounted adjacent the PCB 10,each of the primary windings 102,103,111 are wound around the respective outer and central limbs 15,16,17 and adjacent the respective corresponding secondary winding 104,105,112.This auxiliary printed circuit board 113 is formed of flexible circuit board material,or on a fibre glass substrate as illustrated in Figure 4 and constructed as a single assembly which locates on the PCB 10 and is soldered,or,alternatively, the auxiliary printed circuit board 113 may be provided by one of the layers of the PCB 10.
In order to enable the transformer assembly 100 to be used effectively when high and low loads are coupled to the secondary windings 104,105,112,the central limb 17 of one of the core pieces 12 is provided with a perpendicularly extending lip 26 extending from one edge so that the central limb portion 17a,17b has a step like vertical cross section as shown in Figure 4.In this way,when the two core pieces 12,13 are received in the apertures 11 on the PCB 10 a stepped gap 27 is provided in the central core portion 17c of the two abutting core pieces 12,13 as shown in Figure 4.By providing this stepped gap 27,the inductance is increased when running on a light load.
As the load increases,and,consequently,the flux density on the central core portion 17c,a point will be reached when the extending lip 26 saturates and,effectively,the gap 27 between the two core pieces 12,13 becomes larger.When integrated this provides better control at both high and low loads.
Energy stored in the gap 27 when either of the MOSFET's 109,110 are on is transferred to the secondary winding 112 of the choke 108 when both the MOSFET's 109,110 are on,thus providing an input and output choke.
Conventional,known,manufacturing techniques are used for etching the windings i.e the copper tracks 21,22,23 on the PCB 10,which is also of a known,conventional type.Similarly,the method of forming the loose windings and auxiliary windings on the flexible circuit board material 113,117,118 use conventional,known,techniques and materials and are coupled to the PCB 10 in any suitable,known,manner.
The core pieces 12,13 are made from any suitable material,for example a high frequency ferrite powder,formed into the correct shape and sintered under pressure.They are coupled together using any suitable technique,for example using adhesive placed around the edges of the core portions.
The apertures 11 are routed out of the PCB 10 on a conventional manner and so have radiused corners.The limb portions 15a;15b, 16a;16b, 17a;17b accordingly have correspondingly radiused corners.
It will be understood,to a person skilled in the art,that various modifications are possible within the sope of the present invention.For example,the core pieces do not have to be substantially the same shape,e.g one could be E-shaped as described above,and one could be a flat plate.It is not necessary to have a stepped gap,and the gap, if present could take several forms e.g an angled gap,a multi-stepped gap or a gap without any step,and it could be of any width as required for the given application.The central limb does not have to be placed eqididistantly between the two outer limbs.The separation in the limbs does not have to be centrally located,but could be provided so that the area of one limb portion is twice that of the other so that one-third,rather than half,fractional turns can be provided.In this way,when a frational turn is provided around the smaller limb portion a voltage one-third of that provided by a single turn would be generated,while a turn around the larger limb would generate a voltage two-thirds of that generated by a single turn.The flux balancing windings for such asymmetrically split limb would have two turns around the smaller limb portion and one turn around the larger limb portion.Other configurations for providing fractional turns are possible.The flux balancing windings may be provided on two adjacent layers of the PCB 10 and connecting through using hole plating,rather than as loose windings.Similarly,as described above,the primary windings can be provided on layers of the PCB rather than as an auxiliary,loose winding.The position of the primary and secondary windings may be reversed.The loose windings could be provided on a thermally conducting material e.g on ceramic substrate,or on a hard printed circuit board material.The PCB may or may not include additional electronic circuitry.Indeed,any transformer application or configuration could be adapted in accordance with the invention.
Claims (19)
1.A transformer assembly for an electrical or electronic circuit provided on a substrate,the assembly comprising a first winding,and a second winding electromagnetically coupled to the first winding wherein at least the first winding is provided on the substrate.
2.A transformer assembly according to claim 1,wherein the first winding is is wound,in a helical configuration,for a predetermined number of turns,on the plane of the substrate.
3.A transformer assembly according to claim 2,wherein the substrate is provided with at least one aperture formed therein,whereby the first winding is configured to run around the at least one aperture,starting at a point adjacent one of the apertures and running helically outwards to a predetermined termination point on the substrate.
4.A transformer assembly according to claim 3 further comprising a transformer core,the transformer core comprising at least one projecting core portion arranged to be received in the at least one aperture such that the first winding is configured to wind around the core portion.
5.A transformer assembly according to claim 3 or claim 4 wherein the substrate is provided with at least one pair of apertures having a columnar arrangement with a separation therebetween,the first winding being configured to run around the at least one pair of apertures in the helical configuration from the starting point to the termination point.
6.A transformer assembly according to claim 5 wherein the first winding is configured to run, from the starting point through the separation and around one of the apertures to form a fractional turn.
7.A transformer assembly according to claim 5 or claim 6 wherein each aperture of the at least one pair has substantially the same area.
8.A transformer assembly according to claim 5 or claim 6 wherein one aperture of the at least one pair of apertures has twice the area of the other aperture of the at least one pair of apertures.
9.A transformer assembly according to any of claims 5 to 8 comprising first and second core portions,one of each of the first and second limb portions being arranged to be received in one of the apertures of the at least one pair of apertures.
10.A transformer assembly according to claim 9 ,further comprising a flux balancing winding provided adjacent and substantially parallel to the first winding,the flux balancing winding having a figure-of-eight configuration such that one turn of the figure-of-eight is configured to run around each of the first and second core portions when received in the respective apertures so that equal amounts of flux are taken from each core portion when current flows in the first winding.
11.A transformer assembly according to claim 10 wherein the flux balancing winding is provided on a first auxiliary substrate.
12.A transformer assembly according to any preceding claim wherein the second winding is provided on a second auxiliary substrate located adjacent and substantially parallel to the first winding on the substrate.
13.A transformer assembly according to any preceding claim wherein the substrate is a printed circuit board.
14.A transformer assembly according to claim 13 wherein the flux balancing winding is provided on two adjacent layers of the printed circuit board.
15.A transformer assembly according to claim 13 or claim 14 wherein the second winding is provided on a layer of the printed circuit board.
16.A transformer assembly as claimed in any of claims 1 to 12 wherein the substrate is of a ceramic material.
17.A transformer assembly according to any of claims 4 to 16 wherein the at least one core portion is provided with a gap therein,whereby the gap saturates when the flux density reaches a predeteremined level thereby providing an effectively larger gap therein.
18.An assembly according to claim 17 wherein the gap has a steplike cross sectional configuration.
19.A transformer assembly as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9400204A GB2285892B (en) | 1994-01-07 | 1994-01-07 | A transformer assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9400204A GB2285892B (en) | 1994-01-07 | 1994-01-07 | A transformer assembly |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9400204D0 GB9400204D0 (en) | 1994-03-02 |
| GB2285892A true GB2285892A (en) | 1995-07-26 |
| GB2285892B GB2285892B (en) | 1997-05-14 |
Family
ID=10748479
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9400204A Expired - Fee Related GB2285892B (en) | 1994-01-07 | 1994-01-07 | A transformer assembly |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2285892B (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2301489A (en) * | 1995-05-26 | 1996-12-04 | Coutant Lambda Limited | A power output module for a power supply unit |
| AU720276B2 (en) * | 1996-09-16 | 2000-05-25 | Pdl Electronics Limited | Improvements relating to inductive assemblies in electronic circuits |
| US6069548A (en) * | 1996-07-10 | 2000-05-30 | Nokia Telecommunications Oy | Planar transformer |
| EP1037221A3 (en) * | 1999-03-11 | 2000-10-04 | Murata Manufacturing Co., Ltd. | Coil device and switching power supply apparatus using the same |
| EP1043736A1 (en) * | 1999-04-07 | 2000-10-11 | Rohde & Schwarz GmbH & Co. KG | Transformer assembly for push-pull amplifier of short or ultrashort wave transmitter |
| US6147583A (en) * | 1998-05-26 | 2000-11-14 | Artesyn Technologies | Transformer assembly |
| WO2002050851A1 (en) * | 2000-12-18 | 2002-06-27 | Ascom Energy Systems Ag | Transformer providing low output voltage |
| GB2435964A (en) * | 2006-03-10 | 2007-09-12 | Commergy Technologies Ltd | A transformer for multi-output power supplies |
| WO2007105187A1 (en) * | 2006-03-10 | 2007-09-20 | Commergy Technologies Limited | A transformer for multi-output power supplies |
| EP1962302A1 (en) * | 2005-12-16 | 2008-08-27 | Murata Manufacturing Co., Ltd. | Composite transformer and insulated switching power supply |
| EP2144070A1 (en) * | 2008-07-11 | 2010-01-13 | Liaisons Electroniques-Mecaniques Lem S.A. | Sensor for high voltage environment |
| CN101459418B (en) * | 2007-12-11 | 2011-09-21 | 奇景光电股份有限公司 | Tuner and transformer thereof formed by printed circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1510084A (en) * | 1975-05-12 | 1978-05-10 | West Electric Co | Electric flash devices |
| EP0318955A1 (en) * | 1987-12-02 | 1989-06-07 | John Fluke Mfg. Co., Inc. | Miniature high frequency power transformer |
| GB2252208A (en) * | 1991-01-24 | 1992-07-29 | Burr Brown Corp | Hybrid integrated circuit planar transformer |
-
1994
- 1994-01-07 GB GB9400204A patent/GB2285892B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1510084A (en) * | 1975-05-12 | 1978-05-10 | West Electric Co | Electric flash devices |
| EP0318955A1 (en) * | 1987-12-02 | 1989-06-07 | John Fluke Mfg. Co., Inc. | Miniature high frequency power transformer |
| GB2252208A (en) * | 1991-01-24 | 1992-07-29 | Burr Brown Corp | Hybrid integrated circuit planar transformer |
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2301489A (en) * | 1995-05-26 | 1996-12-04 | Coutant Lambda Limited | A power output module for a power supply unit |
| GB2301489B (en) * | 1995-05-26 | 2000-02-09 | Coutant Lambda Limited | A power output module for a power supply unit |
| US6069548A (en) * | 1996-07-10 | 2000-05-30 | Nokia Telecommunications Oy | Planar transformer |
| AU720276B2 (en) * | 1996-09-16 | 2000-05-25 | Pdl Electronics Limited | Improvements relating to inductive assemblies in electronic circuits |
| US6147583A (en) * | 1998-05-26 | 2000-11-14 | Artesyn Technologies | Transformer assembly |
| EP1037221A3 (en) * | 1999-03-11 | 2000-10-04 | Murata Manufacturing Co., Ltd. | Coil device and switching power supply apparatus using the same |
| US6281779B1 (en) | 1999-03-11 | 2001-08-28 | Murata Manufacturing Co., Ltd. | Coil device and switching power supply apparatus using the same |
| EP1043736A1 (en) * | 1999-04-07 | 2000-10-11 | Rohde & Schwarz GmbH & Co. KG | Transformer assembly for push-pull amplifier of short or ultrashort wave transmitter |
| WO2002050851A1 (en) * | 2000-12-18 | 2002-06-27 | Ascom Energy Systems Ag | Transformer providing low output voltage |
| EP1962302A1 (en) * | 2005-12-16 | 2008-08-27 | Murata Manufacturing Co., Ltd. | Composite transformer and insulated switching power supply |
| EP1962302A4 (en) * | 2005-12-16 | 2013-05-29 | Murata Manufacturing Co | Composite transformer and insulated switching power supply |
| GB2435964A (en) * | 2006-03-10 | 2007-09-12 | Commergy Technologies Ltd | A transformer for multi-output power supplies |
| WO2007105187A1 (en) * | 2006-03-10 | 2007-09-20 | Commergy Technologies Limited | A transformer for multi-output power supplies |
| GB2435964B (en) * | 2006-03-10 | 2010-02-24 | Commergy Technologies Ltd | A transformer for multi-output power supplies |
| US8305183B2 (en) | 2006-03-10 | 2012-11-06 | Texas Instruments (Cork) Limited | Transformer for multi-output power supplies |
| CN101459418B (en) * | 2007-12-11 | 2011-09-21 | 奇景光电股份有限公司 | Tuner and transformer thereof formed by printed circuit |
| EP2144070A1 (en) * | 2008-07-11 | 2010-01-13 | Liaisons Electroniques-Mecaniques Lem S.A. | Sensor for high voltage environment |
| US8022802B2 (en) | 2008-07-11 | 2011-09-20 | Liaisons Electroniques-Mecaniques Lem Sa | Sensor for high voltage environment |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2285892B (en) | 1997-05-14 |
| GB9400204D0 (en) | 1994-03-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20030107 |