PATENT DOCUMENT

Publication Number: US-7804025-B2
Application Number: US-78436607-A
Country: US
Kind Code: B2

Title: Compact magnetic cable noise suppressor

Abstract:
A compact magnetic cable noise suppressor may be provided for suppressing electromagnetic cable noise. The compact magnetic noise suppressor may be formed from a ferrite material or other magnetic material with a high permeability. The compact magnetic cable noise suppressor may be mounted within a chassis of a cable connector or may otherwise be attached to a cable. The magnetic cable noise suppressor may have portions that define a cable entrance, a cable exit, and a cable path. The cable path contains at least one bend. The cable path may contain multiple bends, may contain loops, may contain spirals, and may contain one or more vertically separated layers. The cable entrance and exit may be aligned or may be at different lateral or vertical positions. The cable entrance and exit may be on opposing sides of the noise suppressor or may be on adjacent sides of the noise suppressor.

Claims:
1. A magnetic cable noise suppressor that suppresses electromagnetic noise in a cable that comprises a plurality of wires, comprising:
 at least one portion defining a cable entrance; 
 at least one portion defining a cable exit; and 
 at least one portion defining a cable path through the magnetic cable noise suppressor for the cable between the cable entrance and the cable exit, wherein at least part of the cable path is curved and wherein the cable path surrounds the cable and the plurality of wires as the cable passes between the cable entrance and the cable exit, wherein the magnetic cable noise suppressor has a vertical dimension and a lateral dimension that is perpendicular to the vertical dimension, wherein the portion defining the cable path comprises at least one portion defining a cable path with multiple levels along the vertical dimension, and wherein the cable entrance is aligned with the cable exit in the lateral dimension. 
 
   
   
     2. The magnetic cable noise suppressor defined in  claim 1  wherein the portion defining the cable path comprise at least one portion defining at least one loop. 
   
   
     3. The magnetic cable noise suppressor defined in  claim 1  wherein the portions comprise a first member and a second member that are joined to form the magnetic cable noise suppressor. 
   
   
     4. The magnetic cable noise suppressor defined in  claim 1  wherein the portions comprise a ferrite material. 
   
   
     5. The magnetic cable noise suppressor defined in  claim 1  wherein the portion defining the cable path comprises at least one portion defining a cable path having only a single bend between the cable entrance and the cable exit. 
   
   
     6. The magnetic cable noise suppressor defined in  claim 1  wherein the portion defining the cable path comprise at least one portion defining a cable path having at least two bends between the cable entrance and the cable exit. 
   
   
     7. The magnetic cable noise suppressor defined in  claim 1  wherein the cable exit and cable entrance are on opposing sides of the magnetic cable noise suppressor and wherein the cable path is longer than a straight path between the cable entrance and the cable exit. 
   
   
     8. The magnetic cable noise suppressor defined in  claim 1  wherein the cable exit and cable entrance are on opposing sides of the magnetic cable noise suppressor and wherein the portion defining the cable path comprises at least one portion defining a spiral path through the magnetic noise suppressor. 
   
   
     9. The magnetic cable noise suppressor defined in  claim 1  wherein the cable path has a circular cross-section. 
   
   
     10. Apparatus comprising:
 at least one cable that contains wires; and 
 a connector attached to at least one end of the cable, wherein the connector contains a magnetic cable noise suppressor that has a cable entrance, a cable exit, and a cable path through which the cable passes between the cable entrance and the cable exit, wherein the cable path surrounds the cable as the cable passes between the cable entrance and the cable exit, and wherein the cable path contains at least one bend, wherein the connector comprises a metal chassis having at least a first chassis and a second chassis portion, wherein the magnetic cable noise suppressor has a first half and a second half, wherein the cable path defines respective channels in the first half and the second half that form the cable path, wherein each of the channels comprises at least one bend, and wherein the magnetic cable noise suppressor is mounted in the metal chassis between the first chassis portion and the second chassis portion. 
 
   
   
     11. Apparatus comprising:
 at least one cable that contains wires; and 
 a connector attached to at least one end of the cable, wherein the connector contains a magnetic cable noise suppressor that has a cable entrance, a cable exit, and a cable path through which the cable passes between the cable entrance and the cable exit, wherein the cable path surrounds the cable as the cable passes between the cable entrance and the cable exit, and wherein the cable path contains at least one bend; and 
 electronic equipment having a housing and having a power supply and a power connector disposed within the housing, wherein the cable is connected between the power supply and the power connector. 
 
   
   
     12. Apparatus comprising:
 at least one cable that contains wires; and 
 a connector attached to at least one end of the cable, wherein the connector is adapted to plug into a handheld electronic device, wherein the connector contains a magnetic cable noise suppressor that has a cable entrance, a cable exit, and a cable path through which the cable passes between the cable entrance and the cable exit, wherein the cable path continuously surrounds the cable as the cable passes between the cable entrance and the cable exit, and wherein the cable path contains at least one bend, wherein the cable path comprises at least two bends and wherein the noise suppressor has a shape that conforms to the bends. 
 
   
   
     13. The apparatus defined in  claim 12  wherein the cable comprises at least one electromagnetic shield layer, wherein the noise suppressor comprises a ferrite having a first portion and a second portion that are joined along a surface that lies in a plane, and wherein the bend lies in the plane. 
   
   
     14. The apparatus defined in  claim 12  wherein the path has a circular cross section, wherein the noise suppressor comprises sides and wherein the cable entrance and the cable exit are not on opposing sides of the noise suppressor.

Description:
BACKGROUND 
   This invention relates generally to electromagnetic noise suppression, and more particularly, to compact magnetic cable noise suppressors. 
   Cables are used to interconnect pieces of electronic equipment and to perform other signal routing duties. For example, cables that are compliant with the Digital Video Interface (DVI) standard are used to interconnect personal computers and computer monitors. Universal serial bus (USB) cables are commonly used to interconnect personal computers with peripherals such as music players, digital cameras, and printers. 
   Cables that carry high frequency signals may emit undesirable radio-frequency electromagnetic radiation. Cables may also be subject to radio-frequency noise from external sources. This is particularly the case in cables that do not use expensive high-quality coaxial termination arrangements. To minimize the impact of external radio-frequency noise sources and to reduce radio-frequency emissions, high-frequency cables are commonly shielded using conductive shielding such as braided copper, spiral windings of copper tape, spiral windings of thin copper wire, and metallized polymer. The conductive shielding serves to prevent external signals from coupling onto the signal wires in the cable and minimizes radio-frequency emissions from the cable that could adversely affect nearby electrical equipment. 
   Particularly when very high frequencies are involved (e.g., signals in the upper megahertz and lower gigahertz range), the use of conductive cable shielding is unable to eliminate all adverse radio-frequency effects. Moreover, in many arrangements the conductive shield of a cable is shorted to the ground of the electrical equipment to which it is connected. If the electrical equipment that is attached to the cable exhibits ground noise, the ground noise can be coupled onto the conductive shielding of the cable. Unless corrective measures are taken, the coupled ground noise can cause the conductive shielding to emit undesirable radio-frequency electromagnetic radiation. 
   Magnetic cable noise suppressors have been developed to address these problems. Magnetic cable noise suppressors are commonly based on toroidal ferrite beads or tubular ferrites. With this type of arrangement, a cable noise suppressor is placed at the end of a cable where it surrounds the signal wires in the cable. The noise suppressor attenuates radio-frequency noise by creating a large impedance at high electromagnetic frequencies. 
   Ferrite beads are typically mounted to the end of a cable in an exposed position. Adequate noise suppression often requires the use of ferrite beads that are large. Large ferrite beads that are mounted to the end of a cable are difficult to conceal and tend to be unsightly and cumbersome. 
   It would therefore be desirable to provide compact magnetic cable noise suppression devices. 
   SUMMARY 
   In accordance with the present invention, a compact magnetic cable noise suppressor may be provided that reduces electromagnetic cable noise while occupying a minimal amount of space. The compact magnetic cable noise suppressor may be formed from a ferrite material or other high-permeability material. The compact magnetic cable noise suppressor may be formed by molding a magnetic material to a desired shape followed by a high-temperature sintering operation. 
   The compact magnetic cable noise suppressor may be formed in multiple parts. For example, the compact magnetic cable noise suppressor may be formed from an upper half and a lower half or from three or more sections. These sections may have channels that define a curved cable path through the compact magnetic cable noise suppressor between an cable entrance and a cable exit. The curved cable path may contain one or more bends, loops, spirals, or other suitable curved path shapes. The curved nature of the cable path in the compact magnetic cable noise suppressor lengthens the path while allowing the dimensions of the noise suppressor to be minimized. 
   The cable entrance and cable exit may be vertically and laterally aligned or may located at different heights or lateral positions relative to one another. The compact magnetic cable noise suppressor may have multiple sides. The cable entrance and cable exit may be located on opposing sides of the compact magnetic cable noise suppressor or may be located on adjacent sides of the compact magnetic cable noise suppressor. 
   The compact magnetic cable noise suppressor may be housed in a cable connector or may be placed within a housing associated with a piece of electrical equipment. With one suitable arrangement, the compact magnetic cable noise suppressor may be formed from two rectangular slabs of ferrite. The curved cable path within the noise suppressor may be defined by channels that lie in a plane at which the two rectangular slabs are joined. The rectangular ferrite portions may be mounted within a metal cable connector between mating chassis portions. 
   Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top view of an illustrative cable with illustrative cable connectors that may use compact magnetic cable noise suppressors in accordance with an embodiment of the present invention. 
       FIG. 2  is a schematic view of illustrative components of a cable that may be used with a connector containing a compact magnetic cable noise suppressor in accordance with an embodiment of the present invention. 
       FIG. 3  is a perspective view of an illustrative cable connector that may contain a compact magnetic cable noise suppressor in accordance with an embodiment of the present invention. 
       FIG. 4  is a perspective view of an illustrative two-piece compact magnetic cable noise suppressor attached to a cable in accordance with an embodiment of the present invention. 
       FIG. 5  is a perspective view of a lower half of the illustrative two-piece compact magnetic cable noise suppressor of  FIG. 4  in accordance with an embodiment of the present invention. 
       FIG. 6  is a perspective view showing how a cable may be mounted in the lower half of the magnetic cable noise suppressor of  FIG. 5  in accordance with an embodiment of the present invention. 
       FIG. 7  is an exploded perspective view showing how two halves of a magnetic cable noise suppressor can be secured using a two-piece chassis in accordance with an embodiment of the present invention. 
       FIG. 8  is a cross-sectional side view of an illustrative compact magnetic cable noise suppressor of the type shown in  FIG. 7  in which the pieces of the two-piece chassis have been joined to one another in accordance with an embodiment of the present invention. 
       FIG. 9  is a cross-sectional side view of illustrative electronic equipment in which a compact magnetic cable noise suppressor is being used to suppress power supply noise on a power supply line in accordance with an embodiment of the present invention. 
       FIG. 10  is a top view of an illustrative compact magnetic cable noise suppressor showing how a cable may follow a path with multiple lateral bends in accordance with an embodiment of the present invention. 
       FIG. 11  is a top view of an illustrative compact magnetic cable noise suppressor showing how a cable may follow a path with multiple longitudinal bends in accordance with an embodiment of the present invention. 
       FIG. 12  is a top view of an illustrative compact magnetic cable noise suppressor showing how a cable may enter and exit sides of the compact magnetic cable noise suppressor that are not parallel to each other in accordance with an embodiment of the present invention. 
       FIG. 13  is a perspective view of an illustrative compact magnetic cable noise suppressor formed from four parts in accordance with an embodiment of the present invention. 
       FIG. 14  is a top view of an illustrative compact magnetic cable noise suppressor that surrounds a cable and that has a curved shape that conforms to the curved path of the cable in accordance with an embodiment of the present invention. 
       FIG. 15  is a perspective view of an illustrative compact magnetic cable noise suppressor that has a curved shape that follows a cable having a path with multiple bends in accordance with an embodiment of the present invention. 
       FIG. 16  is a top view of a compact magnetic cable noise suppressor that has a looped cable path in accordance with an embodiment of the present invention. 
       FIG. 17  is a side view of the compact magnetic cable noise suppressor of  FIG. 16 . 
       FIG. 18  is a side view of a compact magnetic cable noise suppressor having a three-layer cable path with lateral bends in accordance with an embodiment of the present invention. 
       FIG. 19  is a top view of the compact magnetic cable noise suppressor of  FIG. 18 . 
       FIG. 20  is a perspective view of an illustrative compact magnetic cable noise suppressor having a spiral cable path in accordance with an embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   Compact magnetic cable noise suppressors may be used to suppress electromagnetic noise on power and signal cables. An illustrative cable of the type that may use a compact magnetic cable noise suppressor in accordance with an embodiment of the present invention is shown in  FIG. 1 . Cable  10  may have connectors such as connectors  14  and  16  and a cable portion such as cable  12 . A compact magnetic cable noise suppressor may be housed within connectors such as connectors  14  and  16 . For example, a compact magnetic cable noise suppressor may be housed within connector  14 . 
   Cable  12  may include any suitable conductive wires. A typical signal cable may include data wires and power wires. If desired, additional components (e.g., optical fiber) may be included in cable  12 . Cable  12  may also be a power cord. 
   Connectors  14  and  16  may be formed using any suitable connector arrangements. With one suitable scheme, connectors  14  and  16  are of different types. For example, as shown in  FIG. 1 , cable connector  16  may be a universal serial bus (USB) connector and cable connector  14  may be a 30-pin cable connector. This is, however, merely illustrative. Connectors  14  and  16  may be the same (e.g., both may be USB connectors or both may be 30-pin connectors, etc.) or connectors  14  and  16  may be different. 
   Connectors  14  and  16  may plug into any suitable electronic equipment. For example, connector  16  may plug into a universal serial bus port on a personal computer and connector  14  may plug into a data port on a handheld electronic device that has music player and cellular telephone capabilities. 
   Connector  14  may have a main body  20  that has a plastic overmold. Connector  16  may have a main body  26  with a plastic overmold. Main body  20  of connector  14  and main body  26  of connector  16  may be formed from any suitable plastic or other dielectric. With one suitable arrangement, body  20  and body  26  are formed of polycarbonate. Strain relief elements  22  and  24 , which may be formed from flexible plastic, may be used to help physically secure cable  12  to connectors  14  and  16 . In a typical connector, metal pins or other suitable electrical contacts (herein collectively “pins”) are used to convey signals from the wires within the cable to external equipment. In the example of  FIG. 1 , connector  14  is shown as having one or more pins  32  and connector  16  is shown as having one or more pins  36 . 
   The number of pins within each connector should generally be equal to or greater than the number of conductive wires within cable  12 . For example, if there are two power wires and two signal wires within cable  12 , there should generally be at least four pins  36  and four pins  32  in connectors  16  and  14 , respectively. If the number of pins on the connectors is insufficient, some wires may be terminated on common pins or some wires may be left unconnected. 
   If desired, there may be more pins on a particular connector than there are within cable  12 . For example, there may be 30 pins  32  within connector  14 , even in embodiments of cable  12  that use only four wires (as an example). 
   Plug portion  28  of connector  16  may have holes  34  that receive corresponding protruding portions on a mating female connector. This arrangement provides friction that helps to hold plug portion  28  to the female connector. Protruding portions  30  on metal plug portion  18  may be used to help secure metal plug portion  18  within a mating connector. Plug portions  28  and  18  may be shorted to ground. 
   With one suitable arrangement, cable  10  may be used in connection with equipment that handles upper megahertz-range and lower gigahertz-range cellular telephone signals and other such high-frequency data signals. Particularly in environments such as these, it can be advantageous to suppress electromagnetic noise. Failure to provide sufficient electromagnetic interference protection in cable  12  may cause high-frequency signals (including signal harmonics at frequencies equal to two times, three times, or even hundreds of times a base tone signal frequency) to be emitted by cable  12  into its surroundings. This emitted radiation may cause harmful interference with other equipment. Moreover, with insufficient electromagnetic interference protection, high-frequency signals from external sources may be coupled onto the cable and passed to equipment that is coupled to the cable. 
   To suppress electromagnetic interference of this type, at least one of the connectors of cable  12  such as connector  14  may be provided with a compact magnetic noise suppressor. In addition, cable  12  may be provided with conductive electromagnetic shielding (sometimes referred to as noise suppressing shielding). 
   Components that may be used to construct an illustrative cable are shown in  FIG. 2 . As shown in  FIG. 2 , strength may be provided to cable  12  using a structural component such as cord  38 . Cord  38  may be formed from any suitable material, although non-conductive materials are generally desired to avoid interfering with the electrical operation of the data wires in cable  12 . With one advantageous arrangement, cord  38  is formed from a high-strength synthetic material such as polyaramid polyparaphenylene terephthalamide (e.g., Kevlar®). Cord  38  may be made up of individual filaments  40  and may have any suitable density (e.g., 1000 denier). 
   Power wires such as power wires  42  and  44  may be used to carry alternating current (AC) or direct current (DC) power signals. Power wire  42  may be a ground wire and power wire  44  may be a positive power supply wire. If desired, there may be more power wires in cable  12 . Power wires such as wires  42  and  44  may have any suitable diameters. With one suitable arrangement, power wires  42  and  44  may be formed of 26 gauge copper. 
   Signals wires  46  such as signal wire  48  and signal wire  50  may be used to carry data signals in cable  12 . There may, in general, be any suitable number of signal wires in cable  12 . With the illustrative embodiment of  FIG. 2 , cable  12  has two signal wires  48  and  50 , which are provided in the form of a twisted pair to improve noise immunity. Signal wires such as wires  48  and  50  may have any suitable diameters. With one suitable arrangement, signal wires  48  and  50  may be formed of 26 gauge copper. When signal wires  48  and  50  are formed of 26 gauge wire and power wires  42  and  44  are formed of 28 gauge wire, the diameters of the conductive cores of signal wires  48  and  50  are smaller than the diameters of the conductive cores of power wires  42  and  44 . This type of arrangement allows the power wires to carry more current than the data wires and provides more room for extra insulation on the data wires to improve data signal integrity. 
   Signal wires  46  and power wires  42  and  44  may be surrounded by conductive shields such as shield  52  and shield  58 . Shield  52  may be formed of from a spiral wrap of conductive film having conductive layer  56  and backing layer  54 . The conductive film may be provided in the form of a metallized plastic strip such as aluminized tape. The plastic backing material for the tape may be formed from a polyester film such as a biaxially-oriented polyethylene terephthalate polyester film (e.g., Mylar®). The layer of deposited aluminum on the tape helps to reduce electromagnetic interference for cable  12 . If desired, conductor  56  may be deposited on both sides of backing  54  or may be deposited on the inner surface of backing  54 . 
   Electromagnetic interference may be further suppressed using shield  58 . Shield  58  may be, for example, a braided conductor. The braided conductor of shield  58  may be formed of copper or other suitable conductors. The braided conductor may have any suitable amount of coverage (e.g., more than 80%, more than 85%, more than 90%, more than 95%, 85-95%, etc.). If the coverage of the braided conductor in shield  58  is too high, cable  12  may become stiff. With one suitable arrangement, the braided conductor in shield  58  is copper braid of approximately 90% coverage. Braided conductor shield  58  and metal film conductive shield  52  may work together to reduce electromagnetic interference under a variety of bending conditions for cable  12 . An advantage of depositing metal  56  on the outer surface of conductive shield tape  62  is that this provides a low impedance conducting path to conductive braid wires  60  of shield  58 . 
   Cable  12  may have drain wire  60 . Drain wire  60  may be a 28 gauge tinned copper wire that helps to electrically attach the metal plug portion  18  of connector  14  to braided shield  58 . 
   Cable  12  may be housed within a plastic overmold formed of polyvinyl chloride plastic or other suitable insulating coating  62 . 
   When cable  12  is plugged into electrical equipment, shields  52  and  58  and drain wire  60  may be shorted to ground. Ground noise that is present on shielding conductors can radiate as undesired electromagnetic signals unless properly suppressed. Additional noise suppression may therefore be provided in the form of a compact magnetic cable noise suppressor. The noise suppressor element may be housed in a connector such as connector  14  of  FIG. 1 . In power cables and other cables that do not have connectors such as connector  14 , the compact magnetic cable noise suppressor may be attached to the cable without enclosing the compact magnetic cable noise suppressor within a connector housing. In cables that have connectors, however, it can be advantageous to place the compact magnetic cable noise suppressor within the connector housing, because this hides the compact magnetic cable noise suppressor from view and thereby helps improve the appearance of the cable. 
   An illustrative cable connector  14  is shown in  FIG. 3 . Main body  20  of connector  14 , which is sometimes referred to as the housing of connector  14 , may be formed from polycarbonate or other suitable materials. Strain relief element  22  may be used to help secure cable  12  to main body  20 . Metal plug portion  18  may contain pins for conveying power and data signals. As shown in  FIG. 3 , connector  20  may be characterized by a longitudinal dimension L that is parallel to cable longitudinal axis  64  and a lateral dimension W that is perpendicular to cable longitudinal axis  64 . Typical values for W and L are on the order of centimeters. 
   Conventional noise suppression elements are bulky, which can lead to unattractively large cable connectors. With a compact magnetic cable noise suppressor arrangement in accordance with an embodiment of the present invention, a noise suppressor structure is provided that is compact enough to allow dimensions such as L and/or W to be minimized without adversely affecting the efficacy of the noise suppressor in suppressing electromagnetic noise. In a typical arrangement, the noise suppressor contains a conduit that allows cable  12  to follow a curved path such as path  66  of  FIG. 3 . In the example of  FIG. 3 , this allows the dimension L to be reduced without reducing the effective length of the magnetic cable noise suppressor along cable  12 . As a result, housing  20  can be made smaller for a given path length than would be possible if the cable followed a straight path through the noise suppressor. 
   An illustrative compact magnetic cable noise suppressor  68  is shown in  FIG. 4 . As shown in  FIG. 4 , compact magnetic cable noise suppressor  68  may have cable entrance  74  and cable exit  76  through which cable  12  passes. As described in connection with  FIG. 3 , compact magnetic cable noise suppressor  68  may have a curved path  66  that extends the length of the cable that passes through the compact noise suppressor without making the compact magnetic cable noise suppressor unduly long in longitudinal dimension L. The length of path  66  within compact magnetic cable noise suppressor  68  may be about 10-15 mm or any other suitable length. 
   Compact magnetic cable noise suppressor  68  may be formed of a high permeability material suitable for suppressing electromagnetic noise. Compact magnetic cable noise suppressor  68  may, as an example, be formed from a ferrite material. Ferrites are generally formed from iron oxide mixed with other metal oxides or metal carbonates (e.g., oxides or carbonates of zinc, nickel, or manganese). The magnetic material of magnetic cable noise suppressor  68  may be provided as a powder and may be formed into a desired shape using a mold. In a typical fabrication process, the molded magnetic material is sintered at an elevated temperature. The sintering process hardens the magnetic material into the shape of the mold. 
   For satisfactory operation of compact magnetic cable noise suppressor  68 , cable  12  preferably follows a path through the solid sintered material that makes up the compact magnetic cable noise suppressor that is longer than a straight path through the solid sintered material would be. For example, in the situation of  FIG. 4 , cable  12  follows a path (path  66 ) that has at least one bent or curved portion and that therefore has a length between cable entrance  74  and cable exit  76  that is greater than the length L of straight path  78  between cable entrance  74  and cable exit  76 . With conventional noise suppressor arrangements, the maximum single-pass length through a noise suppression ferrite would be limited to L. In contrast, the compact magnetic cable noise suppressor arrangement of  FIG. 4  allows the length of path  66  to be significantly longer than L. This maximizes the noise suppression capabilities of the compact magnetic cable noise suppressor without making the noise suppressor unnecessarily bulky. 
   Because the sintered noise suppression material that makes up noise suppressor  68  is generally hard, the compact magnetic cable noise suppressor  68  may be assembled from individual parts. When assembled, the noise suppressor contains a conduit along path  66  that may continuously surround cable  12  as cable  12  passes from cable entrance  74  to cable exit  76 . In general, noise suppressor  68  may be formed from one unitary part, from two parts, from three parts, from four parts, from more than four parts, etc. In the example of  FIG. 4 , compact magnetic cable noise suppressor  68  is formed from two pieces: upper half  70  and lower half  72 . 
   Lower half portion  72  of compact magnetic cable noise suppressor  68  is shown in  FIG. 5 . As shown in  FIG. 5 , a lower portion of path  66  may be formed by channel  80  in lower half portion  72 . Channel  80  may have a semicircular cross section. A corresponding channel may be formed in upper half portion  70  of compact magnetic cable noise suppressor  68  and may also have a semicircular cross section. When the upper and lower portions of compact magnetic cable noise suppressor  68  are joined together along the plane that includes upper surface  73  of lower half portion  72 , the channels form path  66 . In particular, the joined portions of compact magnetic cable noise suppressor  68  may form a conduit with a circular cross section through which cable  12  may pass. 
   The path  66  may have any suitable shape. Cables such as cable  12  are often round in cross section. In this type of situation, compact magnetic cable noise suppressor  68  may have a cable path with a matching circular cross section. The cross-sectional shape of the cable path may also be rectangular, square, triangular, polygonal, oval, or any other desired shape. Satisfactory noise suppression results may be obtained by constructing the path in compact magnetic cable noise suppressor  68  so that it is only slightly larger than cable  12 . In this type of situation, the lateral dimensions of cable  12  (i.e. the diameter of a round cable) will match the lateral dimensions of path  66  (i.e., the diameter of a circular path) so that the cable path will continuously surround the cable as the cable passes between the cable entrance and the cable exit. There are generally no gaps between the outer surface of the cable and the inner surface of the compact magnetic cable noise suppressor cable path. 
     FIG. 6  shows how a round cable may be mounted in channel  80  of lower half portion  72  of compact magnetic cable noise suppressor  68 . Mating upper half portion  70  of compact magnetic cable noise suppressor  68  may be placed on top of cable  12  to form compact magnetic cable noise suppressor  68  as shown in  FIG. 4 . 
   Portions of compact magnetic noise suppressor  68  such as portions  70  and  72  may be held together using any suitable technique. For example, portions such as portions  70  and  72  may be affixed to one another using adhesive, screws or other fasteners, etc. If desired, portions such as portions  70  and  72  may be secured using parts of a connector chassis. 
   An illustrative connector chassis is shown in  FIG. 7 . Connector chassis  82  of  FIG. 7  may form structural support for a connector such as connector  14  of  FIG. 1 . Chassis  82  may be formed from an upper chassis portion such as upper chassis portion  84  and a lower chassis portion such as lower chassis portion  92 . Upper and lower chassis portions  84  and  92  may be formed from metal or any other suitable material. Chassis portions  84  and  92  may have sidewalls  86 . Sidewalls  86  may be formed from bent metal tabs. Connectors  90  may be used to secure upper chassis portion  84  to lower chassis portion  92 . In a typical arrangement, some of the connectors  90  may be holes and some of the connectors  90  may be matching tabs that fit into the holes and lock chassis portions  84  and  92  together during assembly. 
   A cross-sectional side view of an illustrative chassis  82  that has been formed by securing an upper chassis portion to a lower chassis portion is shown in  FIG. 8 . As shown in  FIG. 8 , once chassis portions  84  and  92  have been connected to each other, the assembled chassis secures upper portion  70  of compact magnetic cable noise suppressor  68  to lower portion  72  of compact magnetic cable noise suppressor  68  along plane  73 . Support members such as support member  92  may be used to help secure cable  12  to chassis  82 . Support member  92  may be formed from metal, plastic, or other suitable materials. If desired, cable  12  can be grounded to chassis  82  using a grounding connector such as connector  94 . Connector  94  may be formed from a piece of bent metal that is welded or otherwise electrically and mechanically attached to chassis  82 . Metal plug  18  may be connected to chassis  82  by capturing portions of plug  18  within mating chassis portions, using screws or other fasteners, with adhesive, using a combination of these techniques or any other suitable mounting technique. 
   After the cable, the compact magnetic noise suppressor, and other components such as plug  18  have been mounted within chassis  82 , chassis  82  may be covered with a plastic overmold to form a completed connector such as connector  14  of  FIG. 1 . Because the cable path between cable entrance  74  and cable exit  76  is not straight, the cable path in the noise suppressor has an effective length that is larger than the longitudinal length L of the noise suppressor. This allows the size of connector  14  to be minimized while providing satisfactory noise suppression. 
   If desired, a compact magnetic cable noise suppressor may be used to suppress electromagnetic noise on a power cable. This type of arrangement is shown in  FIG. 9 . In the example of  FIG. 9 , electrical equipment  94  has a power supply  96 . Power is provided to power supply  96  from a wall outlet using power plug  104 , power cable  102 , connector  100 , connector  98 , and interior power cable  12 . As shown in this example, interior power cable  12  may be contained within the housing of electrical equipment  94 . As a result, space may be at a premium. Particularly in environments such as these, it may be desirable to use a compact magnetic cable noise suppressor such as noise suppressor  68 . As shown in  FIG. 9 , compact magnetic cable noise suppressor  68  may be placed on power cable  12  between connector  98  and power supply  96 . Because compact magnetic cable noise suppressor  68  has compact dimensions, use of compact magnetic cable noise suppressor  68  in equipment  94  may make it possible to minimize the amount of space consumed by the noise suppressor in equipment  94 , while at the same time avoiding the use of an unsightly external noise suppressor on cable  102 . 
     FIG. 10  is a top view of an illustrative compact magnetic cable noise suppressor showing how path  66  may have multiple bends  106 . In the arrangement of  FIG. 10 , the bends in path  66  cause path  66  to meander back and forth along lateral dimension  110 , while progressing from cable entrance  74  to cable exit  76  along longitudinal dimension  112 , parallel to longitudinal axis  108  of compact magnetic cable noise suppressor  68 . 
   In the arrangement of  FIG. 11 , bends  106  cause path  66  to meander back and forth along longitudinal dimension  112  (parallel to longitudinal axis  108 ), while progressing laterally along dimension  110 . Unlike the arrangement of  FIG. 10 , in which cable exit  76  and cable entrance  74  are laterally aligned, with the arrangement of  FIG. 11 , cable entrance  74  and cable exit  76  are laterally offset with respect to each other. In both the configuration of  FIG. 10  and the configuration of  FIG. 11 , however, the cable exit and cable entrance are on opposing sides of the compact magnetic cable noise suppressor. 
   If desired, cable path  66  may route the cable  12  through compact magnetic cable noise suppressor so that cable entrance  74  and cable exit  76  are not on opposing sides. This type of arrangement is shown in  FIG. 12 . As shown in  FIG. 12 , cable entrance  74  is formed on wall  114  of compact magnetic cable noise suppressor  68 , whereas cable exit  76  is formed on adjacent wall  116  of compact magnetic cable noise suppressor  68 . Unlike the arrangements of FIGS.  10  and  11  in which the cable entrances and cable exits were formed on opposing sides of compact magnetic cable noise suppressor  68 , with the arrangement of  FIG. 12 , cable entrance  74  is formed in a wall that is perpendicular to the wall in which cable exit  76  is formed. 
   Compact magnetic cable noise suppressor  68  may be formed from any suitable number of individual pieces. In the example of  FIG. 4 , compact magnetic cable noise suppressor  68  was formed from upper portion  70  and lower portion  72 . The upper and lower portions were joined at a plane that contains the cable path. An illustrative arrangement in which compact magnetic cable noise suppressor  68  has been formed from four pieces is shown in  FIG. 13 . As shown in  FIG. 13 , compact magnetic cable noise suppressor  68  has upper left portion  70 A and upper right portion  70 B. Compact magnetic cable noise suppressor  68  of  FIG. 13  also has a lower left portion  72 A and a low right portion  72 B. Line  120  indicates the boundary between the upper portions and the lower portions of compact magnetic cable noise suppressor  68 . Line  118  indicate the boundary between the left-hand portions and the right-hand portions of compact magnetic cable noise suppressor  68 . Cable path  66  may follow the intersection of boundary  118  and boundary  120 . 
   As shown in  FIG. 14 , compact magnetic cable noise suppressor  68  need not be rectangular in shape. In the example of  FIG. 14 , compact magnetic cable noise suppressor  68  has been formed in a serpentine shape that follows a serpentine cable path  66  between cable entrance  74  and cable exit  76 . An advantage of using a non-rectangular shape of the type shown in  FIG. 14  is that it may conserve magnetic material and weight. Rectangular shapes may be advantageous in situations in which perpendicular sidewalls facilitate assembly. 
   Another example of a compact magnetic cable noise suppressor that has a non-rectangular shape is shown in  FIG. 15 . In the configuration shown in  FIG. 15 , compact magnetic cable noise suppressor  68  has upper portion  70  and lower portion  72 . There are three bends  106  in cable path  66  between cable entrance  74  and cable exit  76 . To reduce weight and minimize the use of magnetic material, the shape of compact magnetic cable noise suppressor  68  of  FIG. 15  conforms to path  66 , as the shape of the compact magnetic cable noise suppressor  68  conforms to path  66  in  FIG. 14 . 
     FIG. 16  is a top view of an illustrative embodiment of compact magnetic cable noise suppressor  68  in which path  66  contains a loop. There is only a single loop (loop  122 ) in the example of  FIG. 16 , although compact magnetic cable noise suppressor  68  may have any suitable number of loops (e.g., two or more loops, etc.). 
     FIG. 17  is a side view of the illustrative compact magnetic cable noise suppressor  68  of  FIG. 16 . In  FIG. 17 , height may be measured along vertical dimension  124 . As shown in  FIG. 17 , cable path  66  may have a height at cable entrance  74  that is different than its height at cable exit  76 . Each layer of path  66  also has a different height. Cable entrance  74  and cable exit  76  are shown as being formed on opposite side walls of compact magnetic cable noise suppressor  68  in the example of  FIG. 17 . If desired, cable entrance  74  and cable exit  76  can be formed on side walls of compact magnetic cable noise suppressor  68  that are not opposite to each other and that are not parallel to each other. 
     FIG. 18  is a side view of an illustrative compact magnetic cable noise suppressor  68  in which path  66  has multiple bends  106  and passes through different heights (positions relative to vertical dimension  124 ).  FIG. 19  is a top view of the illustrative compact magnetic cable noise suppressor  68  of  FIG. 18 . In  FIGS. 18 and 19 , the solid line corresponds to the highest portion of path  66 , the dashed-and-dotted line corresponds to the lowest portion of path  66 , and the dashed line corresponds to a portion of path  66  that lies between the solid line portion and the dashed-and-dotted line portion. 
   Although the example of  FIGS. 18 and 19  includes a three levels of cable path  66  each of which contains multiple bends  106 , this is merely illustrative. Any suitable number of levels and bends may be used if desired. 
     FIG. 20  shows an illustrative embodiment of a compact magnetic cable noise suppressor that has a spiral cable path. As shown in  FIG. 20 , path  66  may form three spiral loops  122  about longitudinal axis  124 . There may be any suitable number of spiral loops  122  in compact magnetic cable noise suppressor (e.g., one spiral loop, two spiral loops, three spiral loops, more than three spiral loops, etc.). The example of  FIG. 20  is merely illustrative. 
   In general, compact magnetic cable noise suppressor  68  may have any suitable number of levels in path  66 , may have any suitable number of bends  106 , may have a path that meanders laterally (as shown in  FIG. 10 ) or longitudinally (as shown in  FIG. 68 ), may have cable entrances and exits that are laterally aligned or are not laterally aligned, may have cable entrances and cable exists that are vertically aligned or that are not vertically aligned, may have cable entrances and exits on opposing sides or on adjacent sides, may have looped paths, may have other suitable arrangements for lengthening cable path  66  while minimizing the dimensions of suppressor  68 , or may have combinations of such arrangements. The examples of  FIGS. 3-20  are merely illustrative. 
   The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20070406
Publication Date: 20100928
Grant Date: 20100928
Priority Date: 20070406
Inventors: TERLIZZI JEFFREY J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01F17/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F2017/065", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F2017/065", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F17/06", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 39826431