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Title:
FLEXIBLE BOBBIN FOR ELECTRICAL COMPONENTS
Document Type and Number:
WIPO Patent Application WO/2019/148267
Kind Code:
A1
Abstract:
There is provided an implementation in which an electronic component is divided into two parts, one for connection to a circuit, and one for establishing as intimate a contact as possible between the energy-excessive device and an energy spreader, dampening, or sinking device.

Inventors:
LEKX, David John (7 Fenelon Dr, Toront, Ontario M3A 3K2, CA)
ORR, Raymond Kenneth (ORR Raymond Kenneth, 304 Mount Selkirk CloseCalgar, Alberta T2Z 2P7, CA)
CRACIUN, Aurora (3259 Klaiman Dr, Mississauga Ontario, L4Y 3C7, CA)
Application Number:
CA2019/000014
Publication Date:
August 08, 2019
Filing Date:
January 30, 2019
Export Citation:
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Assignee:
CELESTICA INTERNATIONAL LP (844 Don Mills Road, Toronto Ontario, M3C 1V7, CA)
International Classes:
H05K1/18; G10K11/16; H01F17/00; H01F19/00; H01F41/08; H05K1/14; H05K7/20
Attorney, Agent or Firm:
SLANEY, Brett J. (Blake, Cassels & Graydon LLP199 Bay Street, Suite 4000, Commerce Court West,Toront, Ontario M5L 1A9, CA)
Download PDF:
Claims:
Claims'.

1. An apparatus comprising:

at least one of one or more electrical components which are free to move in at least one dimension;

a set of one or more electrical terminals that has motion independent of the one or more electrical components;

a mechanism to electrically connect the one or more electrical components to the set of one or more electrical terminals that allows substantially independent motion between the electrical components and the terminals;

an energy dissipating surface that is normal to the independent motion of the electrical components; and

a mechanism to couple forces to the one or more electrical components to provide a path to the energy dissipating surface.

2. The apparatus of claim 1 , wherein the one or more electrical components are wound electrical components.

3. The apparatus of claim 2, wherein the wound component is capacitor.

4. The apparatus of claim 2, wherein the wound component is an inductive element.

5. The apparatus of claim 4, wherein the inductive element is a transformer.

6. The apparatus of claim 4, wherein the inductive element is an inductor.

7. The apparatus of claim 4, wherein the inductive element is a relay.

8. The apparatus of claim 1 , wherein the electrical component is a resistor.

9. The apparatus of claim 1 , wherein the electrical component is a semiconductor.

10. The apparatus of any one of claims 1 to 9, wherein the energy dissipating surface is to dissipate thermal energy.

1 1. The apparatus of any one of claims 1 to 9, wherein the energy dissipating surface is to dissipate acoustic energy.

12. The apparatus of any one of claims 1 to 1 1 , wherein the mechanism to couple forces comprises a resilient member.

13. The apparatus of claim 12, wherein the resilient member comprises a spring element.

14. The apparatus of claim 13, wherein the spring element is a compression spring, a Belleville washer, a leaf spring, a custom spring setup, or an array of such spring types.

15. The apparatus of any one of claims 1 to 1 1 , wherein the mechanism to couple forces is an adhesive.

16. The apparatus of any one of claims 1 to 1 1 , wherein the mechanism to couple forces is a pneumatic means, be it a cylinder or other arrangement.

17. The apparatus of any one of claims 1 to 1 1 , wherein the mechanism to couple forces is a hydraulic means, be it a cylinder or other mechanism.

18. The apparatus of any one of claims 1 to 1 1 , wherein the mechanism to couple forces is a compressed sponge.

19. The apparatus of any one of claims 1 to 1 1 , wherein the mechanism to couple forces is a flexible arm.

20. The apparatus of claim 12, wherein the spring element is a mechanism including a spring.

21. The apparatus of claim 12, wherein the spring element is a cantilevered arm in tension or compression.

22. The apparatus of any one of claims 1 to 21 , wherein the force is applied away from the PCB towards a surface instead of through the PCB towards a surface.

23. A bobbin for a magnetic component wherein the central part of the bobbin is free to move in at least one direction, to adjust to the height of a mating part.

24. The bobbin of claim 23, wherein the mating part is a heatsink, a heat spreader, a heat pipe, or a surface.

25. A bobbin for a magnetic component which is free to move in at least one direction, to allow flexibility in placement of the windings in that direction.

26. The bobbin of claim 25, with multiple parts wherein a base and a central part are free to move relative to each other.

27. The bobbin of claim 25, with multiple parts wherein a base has posts and clips to hold the central part steady during attachment of the wire to pins, but which are removable after joining of the wires to the pins.

28. The bobbin of claim 27, with one or more added spring features to bias

movement/location in a desirable direction.

29. The bobbin of claim 27, with insulative coatings applied to enable multiple materials to be used.

30. A single-piece or multiple-piece bobbin for a magnetic component wherein parts of the bobbin incorporate spring-like features to enable motion between a base and a central part, or to bias a resting position in certain directions.

31. The bobbin of claim 30, wherein spring clips, flat springs, or coil springs are embedded by a mechanism.

32. The bobbin of claim 31 , wherein the mechanism is overmolding, loosely fit, tightly fit, glued, staked, or pressed into the bobbin to ensure ongoing pressure or resistance in certain directions.

Description:
FLEXIBLE BOBBIN FOR ELECTRICAL COMPONENTS

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims the benefit of priority to U.S. Provisional Patent

Application No. 62/623,930 filed on January 30, 2018, the contents of which are

incorporated herein by reference.

TECHNICAL FIELD

[0002] The following relates to flexible bobbins for electrical components, such as transformers.

BACKGROUND

[0003] Electrical components on printed circuit boards (PCBs) typically include a body housing an electronic device and leads or pads mounting them on the PCB for both mechanical mounting, and electrical connections for the intended purpose(s) of the PCB’s circuit(s). In pin-through-hole components, this is accomplished via pins from the device which mount through a hole in the PCB, with the hole being subsequently filled with solder for a reliable electrical and mechanical bond/mounting connection. In the case of surface mount devices, leads are largely eliminated and the connections are done through solder pads on the PCB and contacts on the surface-mount device. In both through-hole and surface mount configurations, the principle holds that the solder connections form both the electrical and mechanical bond/mounting for the body of the component.

[0004] A common challenge in electronics design is managing the heat energy generated and loss from inefficient components. Electronic device packaging is commonly designed with thermal energy management in mind and can include features such as having a region of the chip body to where they direct heat and make accommodating features for heatsink applications, etc., whether at the top, bottom, or elsewhere on the device. The art of thermal management has evolved and created considerable expertise in the manner of moving this heat away via these methods, through application of thermal interface materials (TIMs) and various kinds of heat-removal tools, such as heatsinks, heat spreaders, heat pipes and other mechanisms and devices.

[0005] In some circumstances, natural or forced convection may be used to dissipate the heat into the surrounding environment. This works well if the device is in a location with good ventilation and/or only a small amount of heat is being dissipated. For devices installed in enclosures with no ventilation or sealed against ingress, with no fan and sufficient heat load to raise inside temperature beyond acceptable limits for the application, good thermal contact via a TIM with the case of the enclosure is typically considered the best way to remove heat from the devices, and this is commonly done. The TIM could include quite a range of approaches, for instance from sponges, pads, grease, or even coating layers or pottant which could fill portions or the entirety of the enclosure cavity. These approaches are all now common approaches.

[0006] Occasionally, a force may be required to be applied to the body of the electronic device to ensure it is in good mechanical contact with the energy dissipating device (e.g., heatsink, chassis, etc.). In this case, commonly used methods can include springs such as coil springs, leaf springs, or Belleville washers to push against the body of the device towards either the PCB or the dissipating device itself. In all of these cases, the electrical connections of the component are directly connected to the body of the component, and so the component body is not substantially, if at all, free to move.

[0007] In some cases, the geometry of the application or components, other constraints or performance parameters on the project preclude such approaches, and another means of dissipating heat energy from the hot spot on the component or PCB is required. The same situation applies for other kinds of energy, such as acoustic energy for example.

[0008] It is an object of the following to address at least one of the above considerations.

SUMMARY

[0009] It has been recognized that to ensure good energy transfer from one device to another, the devices should be in as close and intimate contact as possible. The following provides an implementation in which the electronic component is divided into two parts, one for connection to the circuit, and one for establishing as intimate a contact as possible between the energy-excessive device and an energy spreader, dampening, or sinking device. The following also provides an implementation in which a single part provides flexibility in a direction.

[0010] In one aspect, there is provided an apparatus comprising: at least one of one or more electrical components which are free to move in at least one dimension; a set of one or more electrical terminals that has motion independent of the one or more electrical components; a mechanism to electrically connect the one or more electrical components to the set of one or more electrical terminals that allows substantially independent motion between the electrical components and the terminals; an energy dissipating surface that is normal to the independent motion of the electrical components; and a mechanism to couple forces to the one or more electrical components to provide a path to the energy dissipating surface. [0011] In another aspect, there is provided a bobbin for a magnetic component wherein the central part of the bobbin is free to move in at least one direction, to adjust to the height of a mating part.

[0012] In yet another aspect, there is provided a bobbin for a magnetic component which is free to move in at least one direction, to allow flexibility in placement of the windings in that direction.

[0013] In yet another aspect, there is provided a single-piece or multiple-piece bobbin for a magnetic component wherein parts of the bobbin incorporate spring-like features to enable motion between a base and a central part, or to bias a resting position in certain directions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Embodiments will now be described with reference to the appended drawings wherein:

[0015] FIG. 1 is a schematic diagram of a typical through-hole mounted electrical component;

[0016] FIG. 2 is a cross-sectional schematic diagram of a standard magnetic mounting configuration;

[0017] FIG. 3 is a cross-sectional schematic diagram of an example of a two-part rigid bobbin configuration;

[0018] FIG. 4 is a cross-sectional schematic diagram of a standard chip with bottom bias for a heatsink;

[0019] FIG. 5 is a cross-sectional schematic diagram of a typical electric component with topside bias for energy dissipation, using a heatsink;

[0020] FIG. 6 is a schematic diagram of a flexible bobbin assembly in one configuration;

[0021] FIG. 7 is a schematic diagram of a flexible bobbin assembly in another configuration;

[0022] FIG. 8 is a series of diagrams illustrating a two-part flexible bobbin in a magnetic application;

[0023] FIG. 9 is an enlarged partial perspective view of a post/clip structure shown in FIG. 8.

[0024] FIG. 10 is a three-dimensional view of a single-piece flexible bobbin

implementation; and [0025] FIG. 11 is a cross-sectional schematic view of a single-piece flexible bobbin implementation.

DETAILED DESCRIPTION

[0026] Turning now to the figures, FIG. 1 shows an example of a typical through-hole mounting configuration 100, in which the electrical terminals 104 providing a mechanical and electrical connection 102 with a circuit board 108 are inflexible at 106. Because of this, there is no freedom of motion for the electrical component relative to the electrical terminals 104 and circuit board 108. Also shown in FIG. 1 is an energy dissipating element 112 below the circuit board 108. It is found that there is inadequate intimate contact 110 for sufficient energy transfer in this configuration. In particular, as shown, there is no direct transfer path for energy transfer. It can be appreciated that similar issues can arise in surface-mount configurations.

[0027] FIG. 2 shows an example configuration 200 of a generic magnetic coil wound about an axis on a bobbin 208, mounted to a PCB 206. In this diagram, the bobbin“feet" 202, 212 are outside, adjacent, and slightly below the area of the windings. It can be appreciated that these may also be underneath the windings, beside the windings or above the windings. It is noted that there is a relatively inflexible connection 106 between the windings and the electrical terminals 104 in contact with the PCB 206, and no freedom of motion of any component after mounting. It is also noted that the configuration 200 shown in FIG. 2 applies regardless of the axis orientation 204 for the magnetic windings. Similar to FIG. 1 , there is an inflexible connection 106 at the electrical terminals 104, here where the rigid bobbin 208 supports pins or pads 202 for mechanical and electrical connections 210. Because of the gap 214 between the windings, core, and PCB 206 or energy dissipating surface 1 12, there is found to be inadequate intimate contact at 110 for sufficient energy transfer.

[0028] FIG. 3 shows an example of a two-part rigid bobbin 300 configuration. In this configuration, a magnetic core 304 is situated between the two-part bobbin 300 with the magnetic windings 204 about the core 304 and bobbin 300. The two part bobbin 300 includes rigid two-part bobbin mounting legs 302 that enable pins or pads for mechanical and electrical connections at 210. The mechanical mounting and electrical connection at 210 to the PCB 206 may be pin-through-hole or surface mount component types. Here the two-part bobbin 300 does not move relative to the PCB 206 and there is no freedom of motion for the electrical component relative to the electrical terminals 104 and circuit board 206. As such, there are inflexible connections 106 and found to be inadequate intimate contact 1 10 for sufficient energy transfer. Similar to what is shown in FIG. 2, there is often a gap between the windings 214, core 304 and PCB 206 or energy dissipating surface 1 12.

[0029] FIG. 4 shows a standard chip configuration 400 with a bottom bias for energy dissipation, usually through a PCB 206 as shown here. In this configuration the component body 404 is in contact with a Thermal Interface Material (TIM) 402 or direct solder connection, but this is an inflexible connection to the PCB 206 or energy dissipation surface 1 12. An inflexible connection 406 between the board 206 and the component 404 may also be observed in FIG. 4. It may be noted that a large percentage of the body of the component 404 is rigidly connected to the PCB 206, leading to good thermal energy path, and also a good path for transferring acoustic energy, with little dampening between the device 404 and the element 206 (shown as a PCB) to which it is mounted.

[0030] FIG. 5 shows a standard chip configuration 500 with topside bias for heatsinking thermal energy. That is, the energy dissipation of the device shown in FIG. 5 is biased towards the top of the device where an energy dissipation element 1 12 is provided, in this case a heatsink. Here there is an inflexible connection 106 to the energy dissipation surface 502, solder, or other TIM 402. The inflexible connection 106 between the board 206 and component 404 is similar to that shown in FIG. 4, with optional additional inflexible connections 106 to the PCB 206 for electrical or mechanical purposes (or both).

[0031] To address the inflexibility and freedom of motion constraints mentioned above, the following provides various implementations for a flexible bobbin assembly.

[0032] FIGS. 6 and 7 show generally the flexible bobbin structure 600. It may be noted that the heat dissipating element 112 may or may not be directly mechanically coupled to the PCB 206, depending on the application. It may also be noted that since the connections 602 are flexible enough to deliver a range of motion, the mechanical contact is governed by either the force generating element 604, or any adhesive between the component body and the dissipating element, otherwise remaining free to move. FIG. 7 shows the device 600 in cross-section extending below the base level of a PCB 108 to an energy-dissipating element 1 12. It may be noted that the image can be interpreted as an opening 700 in a single PCB 108 or as a device between two adjacent PCBs 108a, 108b. Both are possible applications of the concept described for the device 1 14. As illustrated in FIGS. 6 and 7, the electrical component 1 14 can be provided with flexible connections 602 to electrical terminals 104 on the circuit board 108. This allows the electrical component 1 14 to permit motion relative to the electrical terminals 104 and the circuit board 108. In this example, a force generating element 604 can be provided, if required, to provide mechanical contact to the PCB 108 for energy dissipation. Here an additional energy dissipating element 112 can be provided adjacent the PCB 108, if desired or required.

[0033] FIGS. 8 and 9 illustrate another configuration in which a two-part bobbin 800 is provided in a magnetic application. It may be noted that after the component 114 is placed and secured on the PCB, the posts 802 may be removed, creating a slack in the line. With the proper force applied, the component 114 is put into intimate contact with the energy dissipating device. As illustrated in FIG. 8, the posts 802 have retention clips 802 for central bobbin retention, prior to attachment of the copper winding to the pins and are maintained until assembly to the PCB assembly. After assembly, the posts may be clipped and removed, or left behind, with a force 604 applied to the central portion of the bobbin 906 (see FIG. 9) to bias it towards the heat energy-dissipating surface(s). The posts 804 are hard stops for the central bobbin insertion, prior to the attachment of copper winding to the pins, and are maintained until assembly to the PCB. After assembly, they may be clipped, creating the above-noted slack in the winding connections to the pins, and a force 604 may be applied to the central portion of the bobbin 906 to bias it towards the heat energy- dissipating surface(s). The posts 802, 804 are shown in greater detail in the close-up diagram of FIG. 9. The central bobbin 906 assembles by sliding downward and snapping into the base bobbin 902. Also, as seen in FIG. 9, the central winding provides magnetic wire connections 904 to the bobbin base pins 900.

[0034] It may be noted when referring to FIGS. 8 and 9 that the floating part of the bobbin 906 assembles into the stationary part of the bobbin 902. After this, the wire 904 is wound around the assembly with the connecting wire 904 hanging into space, and the floating bobbin 906 with windings are snapped into the base 902 and retained by the post 802 and clip structure best seen in FIG. 9, while the winding wire is connected to the pins 900 that are soldered to the PCB. After the magnetic component has been mounted to the PCB, the aforementioned posts can be clipped off at 804 or otherwise removed so that the central part of the bobbin is free to move in an axis parallel to the pins mounting it to the PCB. If a force 604 (spring or otherwise) is applied to the central floating windings on the floating bobbin 906, it will become in close intimate contact with whatever surface it bears against. This can enable the establishment of a good energy-dissipating (heatsinking) arrangement.

[0035] Turning now to FIGS. 10 and 11 , a single-piece flexible bobbin implementation is shown. In this implementation, a single-piece bobbin 1000 maintains the same flexibility of motion in an axis as the above-described implementations. Similarly, if a force is applied, the body of the component 1008 that needs to dissipate heat (or other energy) is put into good intimate contact with another energy-dissipating device to facilitate improved operations.

[0036] More specifically, referring to the cross-section of FIG. 11 , the single flexible bobbin includes a central body 404 that carries a magnetic core 304 and includes relatively narrow flexible legs 1002 that extend outwardly and downwardly for attachment to the PCB 206, in this example through pin attachments. The flexibility of the legs enables the singlepiece arrangement since the legs can flex under the influence of a downward force. A winding is provided around the magnetic core 304 and bobbin 404 with free ends 1102 that follow the flexible legs 1002 towards the pin attachments 302 to provide the electrical connections to the PCB 206. An energy-dissipation element 1 12 can be provided below the single-piece bobbin 1000, e.g., through an opening in the PCB 1104 as illustrated in FIG. 11 , to allow the force 604 on the component 404 to put the bobbin in close intimate contact with the energy-dissipating element 112 for energy dissipation.

[0037] In the examples shown in FIGS. 6-11 , it can be appreciated the force/bias 604 is towards the energy dissipating surface 1 12, not necessarily the same direction as PCB 206, or surface PCB is mounted on. It can also be appreciated that while FIG. 1 1 may illustrate the energy dissipation element 1 12 emerging through the PCB 206 with no gap between the PCB 206 and the element 112, the PCB 206 edges and the element 1 12 need not be in contact and in many implementations include a gap due to tolerance issues. Moreover, while FIG. 11 may illustrate a gap between the bobbin body and the cored and the energy dissipation surface. However, the gap call also be filled with a TIM, e.g., that is compressed adequately by the force 604 being applied.

[0038] It has been recognized that an advantageous way to ensure good energy transfer from one device to another is for them to be in as close and intimate contact as possible. If this is not possible for whatever reason, it typically presents a challenge. The solution provided herein is to divide the component into two parts, one for a connection to the circuit, and one for establishing as intimate a contact as possible between the energy- excessive device and an energy spreader, dampening, or sinking device (shown generally in FIGS. 6 and 7 described above).

[0039] A good example of the need for the solution can be observed in magnetic components where copper is wound about a bobbin, and where the core may be inside that winding or outside it, or both. Examples of typical magnetic structures are shown in FIGS. 1 and 2, wherein windings about a plastic bobbin electrically insulate a core which is inserted into the bobbin after winding. These figures show a generic connection to component pins 202. It can be understood that these pins 202 may be in many orientations and locations and shapes, but that they are generally fixed in position relative to the position of the portion of the bobbin which surrounds the core 114.

[0040] Bobbins for transformers include an electrically insulative mechanical structure for wire to be wound about a magnetic core 208. This arrangement can include but is not limited to, inductors and transformers. Typical state of the art is for non-flexible bobbins of one or more parts to achieve the desired geometry. However, typical geometry may preclude adequate cooling of both the core and the wire if there is no significant air current or other means cooling the devices because there is no reliable thermal path to a heatsink, absent a potting solution. By making the bobbin flexible, either by splitting the bobbin into 2 parts, with a“foot” for connections to a PCB 206, and a floating central bobbin 906, winding, and core structure, or by having a rigid base connection to the PCB, and a central bobbin, core and windings tied to each other but with motion relative to the bases, the solutions provided herein aim to address this gap.

[0041] For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the examples described herein. However, it will be understood by those of ordinary skill in the art that the examples described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the examples described herein. Also, the description is not to be considered as limiting the scope of the examples described herein.

[0042] It will be appreciated that the examples and corresponding diagrams used herein are for illustrative purposes only. Different configurations and terminology can be used without departing from the principles expressed herein. For instance, components and modules can be added, deleted, modified, or arranged with differing connections without departing from these principles.

[0043] Although the above principles have been described with reference to certain specific examples, various modifications thereof will be apparent to those skilled in the art as outlined in the appended claims.