Abstract:
A magnetic component includes a bobbin structure adapted for attachment to a circuit board. The magnetic component may include a magnetically permeable core and a conductive winding. The bobbin structure may include a gap for inserting the edge of a circuit board. Potential applications of the magnetic component include mechanically and electrically interconnecting two or more circuit boards in a substantially side-by-side configuration while providing increased heat dissipation from the magnetic component, improving power density of the electronic device, reducing electronic device profile, allowing magnetic isolation between high-voltage and low-voltage circuits and allowing single-sided and double-sided circuit boards to be used in a single circuit. Also, a circuit board assembly may have two or more circuit boards electrically and mechanically connected by at least one magnetic component.

Description:
A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. 
     CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims benefit of the following patent application(s) which is/are hereby incorporated by reference: None 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to structures for mechanically and electrically interconnecting circuit boards using a circuit component. More particularly the present invention relates to magnetic circuit components such as a transformer having a bobbin structure adapted for electrically and mechanically interconnecting two or more circuit boards in a substantially side-by-side configuration. 
     Magnetic circuit components such as transformers and inductors are commonly used in a variety of electrical applications, including power supplies. Generally, a magnetic circuit component may include an electrically conductive winding positioned around a core made of a magnetically permeable material. Typically, a core is made of a ferrite. The conductive winding is positioned on a bobbin structure shaped for receiving the core. Additional conductive windings may be placed around the same core or bobbin structure. A second core may also be positioned near the conductive winding to form a closed-loop magnetic flux path around the bobbin structure. Each coil, or winding, may include one or more turns. The electrical characteristics of the component generally depend on the number of turns of each conductive winding and the relative placement of each winding around the core or cores. 
     Conventional magnetic circuit components are generally configured for surface mounting onto a circuit board using terminal connection pins extending from the component body. The connection pins are placed into holes on the surface of a circuit board and are soldered to electrical connection locations on the circuit board, thereby mechanically attaching the component to the circuit board while electrically connecting the component to the circuit. Typically, parts of the electric circuit to which a magnetic component is connected are printed directly onto a circuit board substrate, forming a printed circuit board. 
     A printed circuit board may be formed in several layers, each layer including a unique pattern of conductive material, known as a multi-layer printed circuit board. One common printed circuit board configuration includes a circuit pattern printed only on one side of a flat, two-sided circuit board, generally referred to as a single-sided printed circuit board. Another conventional printed circuit board configuration includes circuit patterns printed directly onto both sides of a circuit board substrate, typically known as a double-sided printed circuit board. Multi-layer and double-sided printed circuit boards require more expensive design, layout and fabrication processes than single-sided printed circuit boards, and it is thus desirable in the art to use single-sided printed circuit boards wherever possible to reduce cost. Many electronic applications and circuit components require the use of a multi-layer or double-sided circuit board either for optimal functionality or for obtaining a desired electronic device profile. 
     The prior art generally teaches the use of a single contiguous double-sided circuit board for an entire circuit in applications where any individual region of a circuit requires a double-sided circuit board. However, it is often desirable to separate one double-sided circuit board into multiple smaller single-sided circuit boards oriented in a side-by-side configuration to reduce costs. A multiple circuit board configuration, however, requires both electrical interconnection among boards and mechanical support between boards. Others have attempted to electrically interconnect adjacent single-sided, double-sided and multi-layer circuit boards in a single circuit using electrical and mechanical connectors between boards. Various types of electrical and mechanical connectors are known for such connection, including sockets, pins, cables, horizontal standoffs and spacers. However, these connector components add additional size, cost and complexity to electric circuits and electronic devices. Prior art connectors also add additional modes of device failure by increasing both the number of individual electrical connections that may become disconnected and the number of mechanical connections that may become dislocated. Also, another design goal in many electronic devices having both high-voltage and low-voltage circuit regions is to provide magnetic isolation between the high-voltage and low-voltage regions. Prior art electrical and mechanical circuit board connectors generally do not provide magnetic isolation between high-voltage and low-voltage circuit regions. 
     Typically, in an electrical device such as a power supply, a circuit board is surrounded by an enclosure to prevent circuit components from being exposed to the environment. During use, magnetic circuit components generate heat locally inside the enclosure. Heat must be dissipated from the component to ensure proper functionality and to prevent circuit damage, component failure, or fire. One mode of heat dissipation from a surface-mounted magnetic circuit component includes heat conduction through a thermal linkage between the magnetic component and the enclosure wall, whereby the enclosure serves as a heat sink. Prior art surface-mount magnetic component configurations, however, limit the ability of a magnetic circuit component to be thermally coupled to an enclosure wall because prior art surface-mount configurations generally place a circuit board between the magnetic component and the enclosure wall. Conventional circuit board placement blocks direct thermal contact between the magnetic component and the enclosure wall. Moreover, the close proximity of the circuit board to the surface-mounted magnetic component in the prior art allows heat conduction by the circuit board, potentially causing damage to nearby circuit components. 
     Others have attempted to solve the problems associated with surface-mounted magnetic component heat dissipation by positioning the magnetic component farther away from the surface of the printed circuit board, using a series of mechanical standoffs to provide an air gap between the component and the circuit board. Because a magnetic component is often the tallest component in a circuit, such prior art raised surface-mount configurations generally increase the maximum height of the circuit extending above the surface of the circuit board, necessitating the use of a larger enclosure. Generally, it is desirable to produce electronic devices having smaller device profiles and increased volumetric power density. In contrast, the prior art approach causes an undesirable increase in the overall size of the electrical device and reduces volumetric power density. Others have also attempted to address the problem of surface-mounted magnetic component heat transfer by adding heat removal structures, such as heat sinks and fins to surface-mounted magnetic components. These structures, however, also take up additional space within the electronic device enclosure, thereby increasing electronic device profile and reducing power density. 
     Accordingly, there is a need in the art for providing a magnetic circuit board connector component for mechanically and electrically connecting circuit boards. The magnetic circuit board connector component must eliminate unnecessary circuit board material, improve heat dissipation from the magnetic component, provide structural support to a circuit board, allow single-sided circuit boards to be used with double-sided printed circuit boards in one circuit, provide magnetic isolation between high-voltage and low-voltage circuit regions, and reduce device profile while increasing power density. Also desired is a circuit board assembly having two or more circuit boards mechanically and electrically interconnected by a magnetic component. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention includes a magnetic component for connecting two or more circuit boards. The magnetic component includes a bobbin structure having a hollow interior cavity. The bobbin structure has a first end and a second end. A first support step is positioned on the first end of the bobbin structure. Similarly, a second support step may be positioned on the second end of the bobbin structure. Each step provides mechanical support between the magnetic component and a circuit board. Each step may also include a side shaped for thermal contact with another surface, such as an enclosure wall, for heat dissipation. One or more conductive terminals extend from the support step for electrically connecting the support step to a circuit board. Each conductive terminal connects to an electrical connection location on the adjacent circuit board. 
     The bobbin structure may include a winding region located between the first and second ends. A conductive winding may be wrapped around the winding region of the bobbin structure. The bobbin winding may include one or more turns around the bobbin structure. A first ferrite core may also be positioned on the bobbin structure. A second ferrite core may be positioned adjacent to the first ferrite core to form a closed-loop magnetic flux path around or through the bobbin structure. 
     The present invention also includes a circuit board assembly having two or more circuit boards electrically and mechanically interconnected by a magnetic component. A first circuit board generally includes a first circuit positioned thereon, and a second circuit board generally includes a second circuit. The first and second circuits are electrically connected through the magnetic component. The electrical connection between the first and second circuit boards may be provided either by magnetic coupling through the magnetically permeable core positioned on the magnetic component or by a direct electrical connection extending between the circuit boards through the magnetic component. As used herein, a first conductor is magnetically coupled to a second conductor where a flow of current through the first conductor generates a magnetic field in a nearby core material that induces a flow of current through the second conductor. Also, as used herein, a first conductor is electrically connected to a second conductor where sufficient electrical contact exists between the conductors to allow a flow of electrons between the conductors. In one embodiment the first and second circuit boards are electrically connected both through a direct electrical connection and through magnetic coupling. 
     The circuit boards are mechanically connected to the magnetic component at circuit board engagement surfaces positioned on the bobbin structure. The circuit board engagement surfaces may be located on the first or second step. Also, a first flange may extend from the first end of the bobbin structure. The first flange includes a first flange surface shaped for supporting the first circuit board. A second flange may also extend from the second end of the bobbin structure, including a second flange surface shaped for supporting the second circuit board. Additional third and fourth flanges may extend from the first and second ends of the bobbin structure to support the first and second circuit boards. 
     It is therefore a general object of the present invention to provide a magnetic component for electrically interconnecting two circuit boards. 
     It is another object of the present invention to provide a bobbin structure for mechanically supporting two circuit boards. 
     It is yet another object of the present invention to provide a magnetic component for eliminating a section of circuit board material in a circuit. 
     It is yet another object of the present invention to provide a magnetic component for connecting a single-sided printed circuit board and a double-sided printed circuit board in a single circuit. 
     It is yet another object of the present invention to provide a magnetic circuit board connector component allowing isolation of high-voltage and low-voltage circuit regions. 
     Another object of the present invention is to provide a magnetic circuit board connector component for increasing power density, decreasing the height of the electric circuit and reducing the device profile. 
     It is yet another object of the present invention to provide a magnetic circuit board connector component for improving heat transfer from the magnetic component to the enclosure wall. 
     Another object of the present invention is to provide a circuit board assembly having two or more circuit boards connected by a magnetic component. 
     Numerous other objects, features and advantages of the present invention will be readily apparent to those skilled in the art, upon a reading of the following disclosure, when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view of a magnetic component in accordance with the present invention. 
         FIG. 2  is a perspective view of a bobbin structure forming part of the magnetic component of  FIG. 1 . 
         FIG. 3  is a top view of a bobbin structure in accordance with the present invention. 
         FIG. 4   a  is an exploded side elevation view of a circuit board assembly in accordance with the present invention. 
         FIG. 4   b  is a side elevation view of the circuit board assembly of  FIG. 4   a.    
         FIG. 4   c  is a detail view of a bobbin structure in accordance with the present invention. 
         FIG. 5  is a perspective view of a magnetic component in accordance with the present invention. 
         FIG. 6  is a perspective view of the bobbin structure forming part of the magnetic component of  FIG. 5 . 
         FIG. 7  is a top view of a bobbin structure in accordance with the present invention. 
         FIG. 8  is a side elevation view of a circuit board assembly in accordance with the present invention. 
         FIG. 9  is a top view of a circuit board assembly in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The magnetic component of the present invention is used as a circuit board connector. The magnetic component includes a bobbin structure that is generally adapted for mounting onto an edge of a circuit board. In one embodiment, a second circuit board is also connected to the magnetic component. Referring now to  FIGS. 1 and 2 , a magnetic component  10  in accordance with the present invention is generally shown. The magnetic component  10  includes a bobbin structure  14  having a winding region  90  and a hollow interior cavity  16 . 
     The bobbin structure  14  includes a first step  20 . The first step  20  has a first circuit board engagement surface  22  adapted for supporting a first circuit board  30 . In one embodiment, the bobbin structure  14  also includes a second step  60 . The second step  60  has a second circuit board engagement surface  62  shaped for supporting the second circuit board  40 . In one embodiment, a first core  70  is positioned on the bobbin structure  14 , and a second core  80  is also positioned on the bobbin structure  14 . Generally, each core  70 ,  80  is made of a magnetically permeable material and can extend into the interior cavity  16  of the bobbin structure  14 . In one embodiment, each core  70 ,  80  includes a ferrite material. 
     Referring further to  FIG. 1 , in one embodiment the first circuit board engagement surface  22  defines a first gap  32  between the first step  20  and the first core  70 . The first gap  32  is generally shaped for receiving the first edge  34  of the first circuit board  30 . Similarly, in one embodiment the second circuit board engagement surface  62  defines a second gap  42  located between the second core  80  and the second step  60 . The second gap  42  is generally shaped for receiving the second edge  44  of the second circuit board  40 . 
     As seen in  FIG. 4   a  and  FIG. 4   b , the first circuit board  30  has a first circuit board thickness  36 , and the first gap  32  has a first gap height  38 . In one embodiment, the ratio of the first circuit board thickness  36  to the first gap height  38  is substantially between 0.5 and 1.0. Also shown in  FIG. 4   a , the second circuit board  40  has a second circuit board thickness  46 , and the second gap  42  has a second gap height  48 . In one embodiment, the ratio of the second circuit board thickness  46  to the second gap height  48  is substantially between 0.5 and 1.0. 
     Referring now to  FIG. 2  and  FIG. 3 , one embodiment of a bobbin structure  14  in accordance with the present invention is shown. The bobbin structure  14  has a first end  54 , a second end  56 , a first step  20  and a second step  60 . A first circuit board engagement surface  22  is positioned on the first step  20  substantially facing a reference plane  18  extending longitudinally through the bobbin structure  14 . A second circuit board engagement surface  62  is positioned on the second step  60  substantially facing the same reference plane  18 . In other embodiments, the first circuit board engagement surface  22  and the second circuit board engagement surface  62  may face in different directions. In one embodiment, a first conductive terminal  28  is positioned on the first step  20 , a second conductive terminal  68  is positioned on the second step  60 , a third conductive terminal  92  is positioned on the first step  20 , and a fourth conductive terminal  94  is positioned on the second step  60 , as shown in  FIG. 3 . In one embodiment, each conductive terminal  28 ,  68 ,  92 ,  94  extends from the bobbin structure  14 , as shown in  FIG. 2  and  FIG. 3 . In other embodiments, various other conductive terminal configurations may be located on the bobbin structure. 
     Referring now to  FIG. 4   a  and  FIG. 4   b , a circuit board assembly or apparatus  120  in accordance with the present invention is shown. The circuit board apparatus  120  includes a first circuit board  30  and a second circuit board  40  connected by a magnetic component  10 , as seen in  FIG. 4   b . The magnetic component  10  includes a first core  70  and a second core  80 . The first circuit board  30  can be positioned in the first gap  32  located between the first core  70  and the first step  20  of the bobbin structure  14 . In one embodiment, the first edge  34  of the first circuit board  30  is inserted into the first gap  32 . The second circuit board  40  includes a second circuit board edge  44  that can be inserted into the second gap  42 , as seen in  FIG. 4   b . In another embodiment, seen in  FIG. 4   c , the first step  20  may define a groove  52 . The first circuit board  30  may be inserted into groove  52  to mechanically connect the first circuit board  30  to the magnetic component  10 . 
     Referring now to  FIG. 5 , another embodiment of a magnetic component  10  is generally shown. The magnetic component  10  includes a bobbin structure  14  having a first end  54  and a second end  56 . The first end  54  of the bobbin structure  14  has a first flange  102  shaped for supporting a first circuit board  30 . The first flange  14  includes a first flange surface  104  for engaging the first circuit board  30 . A second flange  106  also extends from the second end of the bobbin structure  14 . The second flange  106  includes a second flange surface  108 . The first flange surface  104  and second flange surface  108  generally face in the direction of the reference plane  18  extending through the bobbin structure  14 , as shown in  FIG. 6 . 
     As seen in  FIG. 7 , the bobbin structure  14  may also include a third flange  110  having a third flange surface  112  and a fourth flange  114  having a fourth flange surface  116 . Referring again to  FIG. 5 , in one embodiment, the first circuit board  30  includes a first circuit board notch  24  shaped for engaging the first end  54  of the bobbins structure  14 . The second circuit board  40  may have a second circuit board notch  64  shaped for engaging the second end  56  of the bobbin structure  14 . 
     As seen in  FIG. 8 , one embodiment of a circuit board assembly  120  in accordance with the present invention includes a first circuit board  30  and a second circuit board  40  connected by a magnetic component  10 . The first circuit board  30  includes a first circuit  84 . The first circuit  84  is electrically connected to the magnetic component  10  through the first conductive terminal  28 . The first circuit board  30  is mechanically attached to the magnetic component  10  by engaging the first flange  102 . 
     A second circuit  86  is included on the second circuit board  40 . The second circuit  86  is electrically connected to the magnetic component  10  through the second conductive terminal  68 . The second circuit board is mechanically attached to the magnetic component by engaging the second flange  106 . 
     In additional embodiments, the first circuit board  30  may be both mechanically and electrically connected to the magnetic component  10  at a first soldered terminal  98 . Similarly, the second circuit board  40  may be both electrically and mechanically connected to the magnetic component  10  at a second soldered terminal  100 . In one embodiment, the first circuit  84  is electrically connected to the second circuit  86  by magnetic coupling through the first and second cores  70 ,  80  of the magnetic component  10 . In another embodiment, a direct electrical connection may extend through the bobbin structure  14  to connect the first and second circuits  84 ,  86 . 
     Referring now to  FIG. 9 , a circuit board assembly  120  in accordance with the present invention is shown. The circuit board assembly  120  includes a first circuit board  30  connected to a second circuit board  40  and a third circuit board  122  through a first magnetic component  10  and a second magnetic component  124 . A third magnetic component  130  can be mounted onto the second circuit board  40  to provide mechanical support to the second circuit board  40  or to connect additional circuit boards to the circuit board assembly  120 . In one embodiment, the third circuit board  122  is electrically connected to the second circuit  40  through first and second magnetic components  10 ,  124 . The circuit board assembly  120  may include additional circuit boards and magnetic components interconnecting each additional circuit board. Additionally, the circuit board assembly  120  may include both single-sided and double-sided circuit boards interconnected in one circuit through magnetic components. In one embodiment, the first circuit board  30  is a single-sided magnetic component and the second circuit board  40  is a double-sided circuit board. 
     Thus, although there have been described particular embodiments of the present invention of a new and useful magnetic circuit board connector component it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.