A transformer assembly including a conductive shield and leads

Abstract

The present invention relates to a transformer assembly including a conductive shield and leads, the transformer assembly comprising a transformer core, at least one primary winding, and at least one secondary winding. The at least one primary winding is wound around the transformer core, and the at least one secondary winding is wound around the transformer core. The transformer assembly further includes a conductive shield and leads. The conductive shield is wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, and the leads are wound around at least a portion of the conductive shield to mechanically and electrically couple the leads to the conductive shield without solder.

Description

Technical Field

[0001] The present invention relates to a transformer assembly including a conductive shield and leads. Background Art

[0002] This section provides background information related to the present invention, which is not necessarily prior art.

[0003] Transformer assemblies sometimes include copper belly bands wound around primary and secondary windings to reduce electromagnetic interference (EMI) generated by the primary and secondary windings. Figure 1 A transformer assembly 100 including a copper belly band 108 wound around a primary winding and a secondary winding is shown. The transformer assembly 100 also includes leads 112 and 114, which are coupled to the copper belly band 108 by solder 109 to fix and electrically connect the leads 112 and 114 to the copper belly band 108. Summary of the Invention

[0004] This section provides a general overview of the present invention and is not an exhaustive disclosure of the full scope of the present invention or all features of the present invention.

[0005] According to one aspect of the present invention, a transformer assembly includes a transformer core, at least one primary winding, and at least one secondary winding. The at least one primary winding is wound around the transformer core, and the at least one secondary winding is wound around the transformer core. The transformer assembly further includes a conductive shield and leads. The conductive shield is wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, and the leads are wound around at least a portion of the conductive shield to mechanically and electrically couple the leads to the conductive shield without solder.

[0006] According to another aspect of the present invention, a method of assembling a transformer including a transformer core is disclosed. The method includes: winding a first wire around the transformer core to form at least one primary winding, winding a second wire around the transformer core to form at least one secondary winding, and winding a conductive shield around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference. The conductive shield includes an inner surface facing the at least one primary winding and the at least one secondary winding and an outer surface facing away from the at least one primary winding and the at least one secondary winding. The method further includes winding a lead around at least a portion of the outer surface of the conductive shield, the outer surface of the at least one primary winding, and the outer surface of the at least one secondary winding to electrically connect the lead to the conductive shield without solder and to inhibit movement of the lead.

[0007] According to still another aspect of the present invention, a transformer assembly includes a transformer core, at least one primary winding, and at least one secondary winding. The at least one primary winding is wound around the transformer core, and the at least one secondary winding is wound around the transformer core. The transformer assembly further includes a lead and a conductive shield. The lead is wound around at least a portion of the at least one primary winding and the at least one secondary winding, the conductive shield is wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, and the conductive shield is wound around the lead to electrically connect the lead to the conductive shield without solder and to inhibit movement of the lead.

[0008] Concept 1: A transformer assembly, comprising:

[0009] A transformer core;

[0010] At least one primary winding wound around the transformer core;

[0011] At least one secondary winding wound around the transformer core;

[0012] A conductive shield wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference; and

[0013] A lead wound around at least a portion of the conductive shield to mechanically and electrically connect the lead to the conductive shield without solder.

[0014] Concept 2: The transformer assembly according to Concept 1, wherein:

[0015] The lead includes two wire ends;

[0016] The conductive shield includes an outer surface;

[0017] A first one of the two wire ends extends beyond the conductive shield at a first location on the outer surface of the conductive shield; and

[0018] A second one of the two wire ends extends beyond the conductive shield at a second location on the outer surface of the conductive shield, the first location and the second location being on opposite sides of the conductive shield.

[0019] Concept 3: The transformer assembly according to Concept 1 or 2, wherein the lead includes a tinned wire.

[0020] Concept 4: The transformer assembly according to any one of Concepts 1 to 3, wherein the conductive shield includes a belly band tape.

[0021] Concept 5: The transformer assembly according to any one of Concepts 1 to 4, wherein the conductive shield includes copper.

[0022] Concept 6: The transformer assembly according to any one of Concepts 1 to 5, further comprising a ground terminal electrically coupled to the at least one primary winding, wherein the lead is electrically coupled to the ground terminal.

[0023] Concept 7: The transformer assembly according to any one of Concepts 1 to 6, further comprising a voltage input terminal electrically coupled to the at least one primary winding, wherein the lead is electrically coupled to the voltage input terminal.

[0024] Concept 8: The transformer assembly according to any one of Concepts 1 to 7, further comprising at least one auxiliary winding wound around the transformer core, wherein the conductive shield is wound around the at least one auxiliary winding to suppress electromagnetic interference.

[0025] Concept 9: The transformer assembly according to any one of Concepts 1 to 8, wherein the at least one primary winding and the at least one secondary winding include a radially outer surface, and the conductive shield is wound to cover at least fifty percent of the radially outer surface.

[0026] Concept 10: The transformer assembly according to any one of Concepts 1 to 9, wherein the lead is wound around the conductive shield at least one and a half turns.

[0027] Concept 11: A switching mode power supply, wherein the switching mode power supply includes a power converter including the transformer assembly according to any one of Concepts 1 to 10.

[0028] Concept 12: The switching mode power supply according to Concept 11, wherein the power converter includes a flyback converter.

[0029] Concept 13: A method of assembling a transformer including a transformer core, the method comprising:

[0030] Winding a first wire around the transformer core to form at least one primary winding;

[0031] Winding a second wire around the transformer core to form at least one secondary winding;

[0032] Winding a conductive shield around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, the conductive shield including an inner surface facing the at least one primary winding and the at least one secondary winding and an outer surface facing away from the at least one primary winding and the at least one secondary winding; and

[0033] Winding a lead around at least a portion of the outer surface of the conductive shield, the outer surface of the at least one primary winding, and the outer surface of the at least one secondary winding to electrically connect the lead to the conductive shield without solder and suppress movement of the lead.

[0034] Concept 14: The method according to Concept 13, wherein winding the lead includes winding the lead using an automatic wire winding machine.

[0035] Concept 15: The method according to Concept 14, wherein the automatic wire winding machine includes a multi-axis automatic wire winding machine.

[0036] Concept 16: The method according to any one of Concepts 13 to 15, wherein winding the lead includes winding the lead around the outer surface of the at least one primary winding and / or around the outer surface of the at least one secondary winding for at least one and a half turns, and winding the conductive shield includes winding the conductive shield around the at least one and a half turns of the lead.

[0037] Concept 17: The method according to any one of Concepts 13 to 16, wherein winding the lead includes winding the lead around the outer surface of the conductive shield for at least one and a half turns.

[0038] Concept 18: A transformer assembly, comprising:

[0039] A transformer core;

[0040] At least one primary winding wound around the transformer core;

[0041] At least one secondary winding wound around the transformer core;

[0042] Leads wound around at least a portion of the at least one primary winding and the at least one secondary winding; and

[0043] A conductive shield wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, and the conductive shield is wound around the leads to electrically connect the leads to the conductive shield without solder and to suppress movement of the leads.

[0044] Concept 19: The transformer assembly according to Concept 18, wherein the leads comprise tinned wires.

[0045] Concept 20: The transformer assembly according to Concept 18 or 19, wherein the leads are wound around the at least one primary winding and the at least one secondary winding for at least one and a half turns.

[0046] Concept 21: The transformer assembly according to any one of Concepts 18 to 20, wherein the conductive shield comprises a copper belly band tape.

[0047] Concept 22: The transformer assembly according to any one of Concepts 18 to 21, further comprising a ground terminal and a voltage input terminal, the ground terminal being electrically connected to the at least one primary winding, the voltage input terminal being electrically connected to the at least one primary winding, wherein the leads are electrically connected to the ground terminal or the voltage input terminal.

[0048] Concept 23: The transformer assembly according to any one of Concepts 18 to 22, further comprising at least one auxiliary winding wound around the transformer core, wherein the conductive shield is wound around the at least one auxiliary winding to suppress electromagnetic interference.

[0049] From the description provided herein, other aspects and fields of application will become apparent. It should be understood that the various aspects of the present invention can be implemented alone or in combination with one or more other aspects. It should also be understood that the description and specific examples herein are for illustrative purposes only and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present invention.

[0051] Figure 1 Is a front view of a transformer assembly according to the prior art including leads soldered to a belly band.

[0052] Figure 2A Front view of a transformer assembly including a conductive shield.

[0053] Figure 2B Front view of a transformer assembly including leads wound around at least a portion of a conductive shield according to an exemplary embodiment of the present invention. Figure 2A of the transformer assembly.

[0054] Figure 3A Front view of a transformer assembly including leads wound around at least a portion of a primary winding and a secondary winding.

[0055] Figure 3B Front view of a transformer assembly including a conductive shield wound around the wound leads according to another exemplary embodiment of the present invention. Figure 3A of the transformer assembly.

[0056] Figure 4 Circuit diagram of a transformer assembly including leads electrically coupled to a voltage input terminal according to another exemplary embodiment of the present invention.

[0057] Figure 5 Circuit diagram of a transformer assembly including leads electrically coupled to a ground terminal according to another exemplary embodiment of the present invention.

[0058] Figure 6A and Figure 6B are Figure 2B Waveforms of an exemplary electromagnetic interference test scan of a transformer at a phase line and a neutral line of 100 volts (V).

[0059] Figure 7A and Figure 7B are Figure 2B Waveforms of an exemplary electromagnetic interference test scan of a transformer at a phase line and a neutral line of 240 volts.

[0060] Throughout the several views of the drawings, corresponding reference numerals indicate corresponding parts or features. Detailed Description

[0061] Exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed and that the exemplary embodiments may be embodied in many different forms and that neither the specific details nor the exemplary embodiments should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies have not been described in detail.

[0062] The terms used herein are for the purpose of describing particular exemplary embodiments only and are not intended to be limiting. As used herein, the singular forms "a", "an", and "the" may also be intended to include the plural forms, unless the context clearly indicates otherwise. The terms "comprising", "including", and "having" are inclusive and therefore specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring them to be performed in the particular order discussed or illustrated, unless the particular order is specifically identified as an order of performance. It will also be understood that additional or alternative steps may be employed.

[0063] Although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or part from another. Terms such as "first" and "second" and other numerical terms do not imply an order or sequence when used herein, unless the context clearly indicates otherwise. Thus, a first element, first component, first region, first layer, or first part discussed below may be referred to as a second element, second component, second region, second layer, or second part without departing from the teachings of the exemplary embodiments.

[0064] For ease of description, spatial relative terms, such as "inner", "outer", "beneath", "below", "lower", "above", "upper", etc., may be used herein to describe the relationship of one element or feature to another element(s) or feature(s) as shown in the figures. In addition to the orientation shown in the figures, the spatial relative terms may also be intended to encompass different orientations of the device during use or operation. For example, if the device in the figures is turned over, an element described as "beneath" or "below" another element or feature will then be oriented "above" that other element or feature. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial relative descriptors used herein are to be interpreted accordingly.

[0065] Exemplary embodiments will now be described more fully with reference to the accompanying drawings.

[0066] A transformer assembly according to an exemplary embodiment of the present invention is shown in Figure 2A and Figure 2B and is generally designated by reference numeral 200. Figure 2AFIG. 200 shows a transformer assembly 200 before the lead 210 is wound around at least a portion of the conductive shield 208, and Figure 2B FIG. 201 shows the transformer assembly 200 after the lead 210 is wound around at least a portion of the conductive shield 208.

[0067] The transformer assembly 200 includes a transformer core 202, a primary winding 204, and a secondary winding 206. The primary winding 204 is wound around the transformer core 202, and the secondary winding 206 is wound around the transformer core 202.

[0068] The transformer assembly 200 further includes a conductive shield 208 (e.g., a copper belly band, etc.) and a lead 210. The conductive shield 208 is wound around the primary winding 204 and the secondary winding 206 to suppress electromagnetic interference.

[0069] As Figure 2B shown, the lead 210 is wound around the conductive shield 208 for one and a half turns (e.g., 1.5 turns, etc.) to mechanically and electrically connect the lead 210 to the conductive shield 208 without solder. As described above, Figure 2A FIG. 200 shows the transformer assembly 200 before the lead 210 is wound around the conductive shield 208, and Figure 2B FIG. 201 shows the transformer assembly 200 after the lead 210 is wound around the conductive shield 208.

[0070] Winding the lead 210 around at least a portion of the conductive shield 208 (such as Figure 2B the 1.5 turns shown) allows for the establishment of a non-welded electrical connection between the conductive shield 208 and the lead 210.

[0071] In contrast to winding the lead 210 around the conductive shield 208 in the transformer assembly 200 shown in Figure 2A and Figure 2B FIG. 201, the prior method of using solder to connect the lead 110 and the copper belly band 108, as shown in Figure 1 FIG. 202, requires additional manual handling or a customized automatic soldering machine that is only suitable for one type of transformer.

[0072] In addition, as Figure 1 shown in FIG. 202, when soldering the lead 110 to the copper belly band 108, solder must be applied to the transformer with the completed windings, which poses a high risk that solder balls will melt into the windings and cause high potential (voltage withstand) failures.

[0073] Another method of connecting the leads and the copper belly band using conductive adhesive makes it difficult to control the quality of the application and relies only on manual or semi-automatic application techniques. Since the adhesive is in a liquid state before curing, many glued transformer components may be discarded for aesthetic reasons, and due to differences in the operator's skill level, more or less inconsistent amounts of adhesive may be used in each transformer.

[0074] Contrary to previous methods of electrically connecting leads to a copper belly band using solder or conductive adhesive, in Figure 2B transformer assembly 200, winding lead 210 around conductive shield 208 can allow the use of an automatic winding machine (e.g., a multi-axis automatic winding machine), can eliminate solder balls and related withstand voltage failures, and can increase productivity by eliminating inefficient manufacturing welding processes and the customization and complexity required for automating the production line for welding.

[0075] Winding lead 210 around conductive shield 208 1.5 times can hold lead 210 on conductive shield 208 (e.g., to mechanically connect lead 210 and conductive shield 208) and establish an electrical connection between lead 210 and conductive shield 208 without using solder or conductive adhesive.

[0076] Lead 210 can then be connected to the voltage input terminals, ground terminals, etc. of transformer assembly 200 as further described below to facilitate electromagnetic interference shielding of transformer assembly 200 and its primary winding 204 and secondary winding 206 through conductive shield 208.

[0077] For example, conductive shield 208 can include any material (such as copper, etc.) suitable for providing electromagnetic interference shielding to transformer assembly 200 and its primary winding 204 and secondary winding 206.

[0078] Each primary winding 204 and each secondary winding 206 can include one or more winding wires (e.g., electrically insulated copper wires, etc.), and the one or more winding wires can be wound in one or more coils (e.g., electrically insulated coils), etc. For example, each primary winding 204 and each secondary winding 206 can be insulated by electrical tape (or any other suitable insulator) to inhibit the electrical connection between conductive shield 208 and primary winding 204 and the electrical connection between conductive shield 208 and secondary winding 206.

[0079] Primary winding 204 and secondary winding 206 can include a radially outer surface, and the conductive shield can be wound around at least a portion of the radially outer surface. In other embodiments, for the outer surfaces of primary winding 204 and secondary winding 206, primary winding 204 and secondary winding 206 can have a rectangular shape, a triangular shape, or any other suitable shape.

[0080] The conductive shield 208 can be wound to cover at least fifty percent of the radial outer surfaces of the primary winding 204 and the secondary winding 206, at least ninety percent of the radial outer surfaces of the primary winding 204 and the secondary winding 206, all of the radial outer surfaces of the primary winding 204 and the secondary winding 206, etc.

[0081] The conductive shield 208 can be a conductive tape material that is flexible, of a suitable thickness, etc. for winding the conductive shield 208 around the primary winding 204 and the secondary winding 206 of the transformer assembly 200, and the conductive shield 208 can be regarded as a transformer "abdominal band".

[0082] For example, Figure 2A and Figure 2B illustrates a conductive shield 208 that is wound to cover most but not all of the radial outer surfaces of the primary winding 204 and the secondary winding 206. Since it is covered by the conductive shield 208, Figure 2A and Figure 2B the primary winding 204 and the secondary winding 206 in are not clearly distinguishable from each other, but the primary winding 204 and the secondary winding 206 can be wound in any suitable transformer arrangement. For example, the primary winding 204 is positioned radially outward from the secondary winding 206, the secondary winding 206 is positioned radially outward from the primary winding 204, the primary winding 204 and the secondary winding 206 are sandwiched between each other, etc.

[0083] The lead 210 can include any suitable wire for establishing an electrical connection between the conductive shield 208 and one or more terminals to facilitate electromagnetic interference shielding through the conductive shield 208, such as a tinned wire, etc.

[0084] The lead 210 can include two wire ends 212 and 214 for electrically coupling to a voltage input terminal of the transformer assembly 200, a ground terminal of the transformer assembly 200, etc. For example, Figure 2B illustrates the wire ends 212 and 214 coupled to the transformer pin 215 of the transformer assembly 200. The transformer pin 215 can be connected to a ground potential, a voltage input end, etc.

[0085] As Figure 2B shown, the wire ends 212 and 214 extend beyond opposite sides of the outer surface of the conductive shield 208. For example, the lead 210 is wound around the conductive shield 208 1.5 times, so the wire ends 212 and 214 extend beyond the conductive shield 208 at approximately opposite sides of the conductive shield 208 to connect to the transformer pins 215 located on opposite sides of the transformer assembly. Although in Figure 2BApproximately 1.5 turns of the lead 210 are shown, but when the lead is wound in the range of 1.1 to 1.9 times (or any multiple of 1.1 to 1.9 times), such as about 1.2 times, about 1.3 times, about 1.4 times, about 1.6 times, about 1.7 times, about 1.8 times, etc., the wire ends 212 and 214 can extend beyond the conductive shield 208 on different sides.

[0086] In other embodiments, the lead can be wound around the conductive shield more or fewer times. For example, the lead 210 can be wound around the conductive shield 208 less than one full turn (e.g., about half a turn around the conductive shield, etc.), and the lead 210 can be fixed in place in contact with the conductive shield 208 via the transformer pin 215. The number of turns or less than one full turn can depend on the capabilities of the automatic winding machine, etc.

[0087] The lead 210 can be wound around the conductive shield 208 more than 1.5 turns (such as 2.5 turns, 3.5 turns, etc.). Increasing the number of turns of the lead 210 can increase the strength of the mechanical and / or electrical connection between the lead 210 and the conductive shield 208. For example, compared with a smaller number of turns, increasing the number of turns of the lead 210 can make the lead 210 more firmly mechanically connected to the conductive shield 208.

[0088] In some embodiments, the wire ends 212 and 214 can extend beyond other portions of the conductive shield. For example, the wire ends 212 and 214 can extend from positions on the conductive shield that are not opposite each other. The wire ends 212 and 214 can be connected to different transformer pins 215 as shown, can be connected to the same transformer pin 215, etc. Figure 2B shown, can be connected to the same transformer pin 215, etc.

[0089] Figure 3A and Figure 3B is a front view of a transformer assembly 300 according to another exemplary embodiment of the present invention. Figure 3A The transformer assembly 300 is shown before the conductive shield 308 is wound around the lead 310, and Figure 3B the transformer assembly 300 is shown after the conductive shield 308 has been wound around the lead 310.

[0090] The transformer assembly 300 includes a transformer core 302, a primary winding 304, and a secondary winding 306. The primary winding 304 is wound around the transformer core 302, and the secondary winding 306 is wound around the transformer core 302.

[0091] The transformer assembly 300 further includes a lead 310 and a conductive shield 308. As Figure 3A shown, the lead 310 is wound around at least a portion of the primary winding 304 and the secondary winding 306. AsFigure 3B As shown, the conductive shield 308 is wound around the primary winding 304 and the secondary winding 306 to suppress electromagnetic interference. The conductive shield 308 is also wound around the lead 310 to electrically connect the lead 310 to the conductive shield 308 without solder and to suppress movement of the lead 310.

[0092] Compared with the transformer assembly 200 in which the lead 210 is wound around the conductive shield 208 Figure 2B in the transformer assembly 300, the conductive shield 308 is wound around the lead 310. Thus, in Figure 2B the transformer assembly 200, the lead 210 extends around (e.g., along, etc.) the outer surface of the conductive shield 208, while in Figure 3B the transformer assembly 300, the lead 310 extends around the radial outer surfaces of the primary winding 304 and the secondary winding 306 (and the inner surface of the conductive shield 308).

[0093] Winding the conductive shield 308 around the lead 310 can hold the lead 310 in place, with only the wire ends 312 and 314 of the lead 310 extending out from under the conductive shield 308. The wire ends 312 and 314 can be connected to establish an electrical connection between the conductive shield 308 and one or more transformer pins 315 (e.g., voltage input terminals, ground input terminals, etc.) to facilitate shielding of electromagnetic interference through the conductive shield 308.

[0094] Figure 4 FIG. is a wiring diagram showing the lead 410 connected to the voltage input terminal V+ (e.g., positive voltage, etc.) of the transformer assembly 400. The transformer assembly 400 includes a primary winding 404, a secondary winding 406, and an auxiliary winding 416. The lead 410 can be considered to be electrically connected to the primary winding 404.

[0095] The lead 410 connects a conductive shield (not shown) to the voltage input terminal V+ (e.g., voltage input pin 415) to facilitate shielding of electromagnetic interference through the conductive shield. For example, connecting the conductive shield to the voltage input terminal V+ via the lead 410 can improve the ability of the conductive shield to suppress noise generated by the primary winding 404 and the secondary winding 406, etc.

[0096] The transformer assemblies described herein can be used in any suitable application, such as a switched-mode power supply, components / modules that require copper or other metal shielding, and other applications that require connecting an EMI shield to a voltage input terminal, a ground / earth pin, etc.

[0097] Figure 4An exemplary switch - mode power supply including a transformer assembly 400 is shown. The switch - mode power supply includes a voltage input terminal V+ for receiving power from a power supply 418, a switch 420 for controlling the current through the primary winding 404, and a diode 422 for selectively supplying current to a load 424.

[0098] Figure 4 The switch - mode power supply shown in Figure 4 can be considered a flyback converter and can include additional components not shown in

[0099] Figure 5 A wiring diagram showing a lead 510 connected to a ground / earth - potential terminal GND (e.g., ground pin 515) of a transformer assembly 500 is shown. The transformer assembly 500 includes a primary winding 504, a secondary winding 506, and an auxiliary winding 516.

[0100] The lead 510 connects a conductive shield (not shown) to the ground / earth - potential terminal GND to facilitate shielding of electromagnetic interference through the conductive shield. For example, connecting the conductive shield to the ground / earth - potential terminal GND via the lead 510 can improve the ability of the conductive shield to suppress noise generated by the primary winding 504, secondary winding 506, etc.

[0101] Figure 5 An exemplary switch - mode power supply including a transformer assembly 500 is shown. The switch - mode power supply includes a voltage input terminal V+ for receiving power from a power supply 518, a switch 520 for controlling the current through the primary winding 504, and a diode 522 for selectively supplying current to a load 524.

[0102] The input terminal V+ and the ground / earth - potential terminal GND can include any suitable connectors, terminals, wires, conductive traces, etc. for receiving power from a voltage source, for establishing an electrical connection to the ground potential, etc.

[0103] As Figure 4 and Figure 5 shown, the conductive shield can be connected to voltage input connections, ground / earth connections, etc. because these connections can provide a relatively stable, firm, etc. voltage level for the transformer assembly.

[0104] The conductive shield can be connected to the voltage input connection, the ground / earth connection, etc. according to the application of the transformer assembly. For example, in some mobile chargers, the conductive shield can be connected to the body voltage input V+, and in some general power supplies, the conductive shield can be connected to the ground / earth, etc.

[0105] Figure 6A and Figure 6B shows Figure 2B an exemplary scan of the electromagnetic interference (EMI) test results of the phase and neutral lines of the transformer assembly 200 shown at 100 volts (V). These test results are based on the International Special Committee on Radio Interference (CISPR) 22 rule standard. Similarly, Figure 7A and Figure 7B shows Figure 2B an exemplary scan of the electromagnetic interference (EMI) test results of the phase and neutral lines of the transformer assembly 200 shown at 240 volts (V).

[0106] Figures 6A to 6B and Figures 7A to 7B shows the consistent shielded EMI conducted through the conductive shield 208 at multiple voltages up to thirty megahertz (MHz). In particular, in the range from 150 kilohertz (kHz) to 30 megahertz (MHz), the quasi-peak EMI voltage level and the average EMI voltage level are below the quasi-peak limit and the average limit respectively in each case.

[0107] For example, as Figures 6A to 6B and Figures 7A to 7B shown, for the CISPR Class B EMI limits for emission frequencies from 0.15 MHz to 0.50 MHz, the quasi-peak limit slopes down from 66 dBuV to 56 dBuV, and the average limit slopes down from 56 dBuV to 46 dBuV. In the emission frequency range from 0.50 MHz to 5.00 MHz, the quasi-peak limit is 56 dBuV and the average limit is 46 dBuV, while in the emission frequency range from 5.00 MHz to 30.0 MHz, the quasi-peak limit is 60 dBuV and the average limit is 50 dBuV.

[0108] As Figures 6A to 6B and Figures 7A to 7B shown, the scan of the EMI test results for the transformer assembly is within the required limits and meets the standards for all test levels. This consistent EMI shielding at all levels can be at least partially due to the consistent production repeatability of winding the lead 210 around the conductive shield 208. This can reduce costs due to higher efficiency and higher yield.

[0109] According to another exemplary embodiment, a method of assembling a transformer including a transformer core is disclosed. The method includes winding a first wire around the transformer core to form at least one primary winding; winding a second wire around the transformer core to form at least one secondary winding; and winding a conductive shield around at least a portion of the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference.

[0110] The conductive shield includes an inner surface facing the at least one primary winding and the at least one secondary winding and an outer surface facing away from the at least one primary winding and the at least one secondary winding.

[0111] The method further includes winding a lead around at least one of the outer surface of the conductive shield, the outer surface (e.g., a portion, etc.) of the at least one primary winding, and the outer surface (e.g., a portion, etc.) of the at least one secondary winding to electrically connect the lead to the conductive shield without solder and to suppress movement of the lead.

[0112] Winding the lead may include winding the lead around the outer surface of the conductive shield for at least 1.5 turns. Alternatively, the lead may be wound around the outer surface of the at least one primary winding or around the outer surface of the at least one secondary winding for at least 1.5 turns, and winding the conductive shield may include winding the conductive shield around the at least 1.5 turns of the lead.

[0113] Winding the lead may include winding the lead using an automatic wire winding machine. For example, winding the lead may include winding the lead using a multi-axis automatic wire winding machine.

[0114] For purposes of illustration and description, the foregoing description of the embodiments has been provided. This is not intended to be exhaustive or to limit the invention. The individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but rather, where applicable, are interchangeable and can be used in the selected embodiment, even if not specifically shown or described. The individual elements or features of a particular embodiment can also vary in a variety of ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.

Claims

1. A transformer assembly, comprising: A transformer core; At least one primary winding wound around the transformer core; At least one secondary winding wound around the transformer core; A conductive shield wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference; A lead wire wound around at least a portion of the conductive shield to mechanically and electrically connect the lead wire to the conductive shield without solder; A ground terminal electrically connected to the at least one primary winding; And A voltage input terminal electrically connected to the at least one primary winding, Wherein the lead wire is electrically connected to the ground terminal or the voltage input terminal.

2. The transformer assembly according to claim 1, wherein: The lead wire includes two wire ends; The conductive shield includes an outer surface; The first wire end of the two wire ends extends beyond the conductive shield at a first position on the outer surface of the conductive shield; And The second wire end of the two wire ends extends beyond the conductive shield at a second position on the outer surface of the conductive shield, and the first position and the second position are on opposite sides of the conductive shield.

3. The transformer assembly according to claim 1, wherein, The lead wire includes a tinned wire.

4. The transformer assembly according to claim 1, wherein, The conductive shield includes a belly band tape.

5. The transformer assembly according to claim 4, wherein, The conductive shield includes copper.

6. The transformer assembly according to claim 1 further includes at least one auxiliary winding wound around the transformer core, wherein, The conductive shield is wound around the at least one auxiliary winding to suppress electromagnetic interference.

7. The transformer assembly according to claim 1, wherein, The at least one primary winding and the at least one secondary winding include a radially outer surface, and the conductive shield is wound to cover at least fifty percent of the radially outer surface.

8. The transformer assembly according to claim 1, wherein, The lead wire is wound around the conductive shield for at least one and a half turns.

9. A switching mode power supply, wherein, The switch-mode power supply includes a power converter including the transformer assembly according to claim 1.

10. The switching mode power supply according to claim 9, wherein, The power converter includes a flyback converter.

11. A method of assembling a transformer including a transformer core, the method comprising: Winding a first wire around the transformer core to form at least one primary winding; Winding a second wire around the transformer core to form at least one secondary winding; Winding a conductive shield around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, the conductive shield including an inner surface facing the at least one primary winding and the at least one secondary winding and an outer surface facing away from the at least one primary winding and the at least one secondary winding; Winding a lead wire around at least a portion of the outer surface of the conductive shield, the outer surface of the at least one primary winding, and the outer surface of the at least one secondary winding to electrically connect the lead wire to the conductive shield without solder and to suppress movement of the lead wire; Electrically connecting a ground terminal to the at least one primary winding; And Electrically connecting a voltage input terminal to the at least one primary winding, Wherein the lead wire is electrically connected to the ground terminal or the voltage input terminal.

12. The method according to claim 11, wherein, Winding the lead wire includes winding the lead wire using an automatic wire winding machine.

13. The method according to claim 12, wherein, The automatic wire winding machine includes a multi-axis automatic wire winding machine.

14. The method according to claim 11, wherein, Winding the lead wire includes winding the lead wire around the outer surface of the at least one primary winding and / or around the outer surface of the at least one secondary winding for at least one and a half turns, and winding the conductive shield includes winding the conductive shield around the at least one and a half turns of the lead wire.

15. The method according to claim 11, wherein, Winding the lead wire includes winding the lead wire around the outer surface of the conductive shield for at least one and a half turns.

16. A transformer assembly, comprising: A transformer core; At least one primary winding wound around the transformer core; At least one secondary winding wound around the transformer core; A lead wire wound around at least a portion of the at least one primary winding and the at least one secondary winding; A conductive shield wound around the at least one primary winding and the at least one secondary winding to suppress electromagnetic interference, and the conductive shield is wound around the lead wire to electrically connect the lead wire to the conductive shield without solder and to suppress movement of the lead wire; A ground terminal electrically connected to the at least one primary winding; And A voltage input terminal electrically connected to the at least one primary winding, wherein the lead wire is electrically connected to the ground terminal or the voltage input terminal.

17. The transformer assembly according to claim 16, wherein, The lead wire includes a tinned wire.

18. The transformer assembly according to claim 16, wherein, The lead wire is wound around the conductive shield for at least one and a half turns.

19. The transformer assembly according to claim 16, wherein, The conductive shield includes a copper belly tape.

20. The transformer assembly according to claim 16 further includes at least one auxiliary winding wound around the transformer core, wherein, The conductive shield is wound around the at least one auxiliary winding to suppress electromagnetic interference.

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