Abstract:
A capacitor assembly is providing for adapting a replacement capacitor to an existing circuit board layout. The capacitor assembly has an adapter with a plate and the replacement capacitor affixed thereto, and the adapter has terminals which are connected to the leads of the replacement capacitor. The adapter further has leads, such as pins, extending downward from the plate, to electrically connect the capacitor assembly to the circuit board.

Description:
[0001]    This invention is directed to an adapter to allow one or more capacitors on a circuit board to be replaced with one or more capacitors. The adapter has a plate and the replacement capacitor(s) is electrically connecting to and supported by the plate. The adapter includes leads extending downward, which allow the adapter to be electrically connected to the circuit board in the location where the original capacitors were connected. 
       BACKGROUND OF THE INVENTION 
       [0002]    A circuit board may be designed with multiple capacitors located in close proximity to each other. Or the circuit board may be designed to accommodate a capacitor having certain lead configurations, such as leads extending from each end of the capacitor or both leads extending from the same end of the capacitor. Accordingly, the circuit board will have through-holes therein or solder pads for surface-mount technology arranged to accommodate the capacitor(s) sped tied for the electrical circuit. 
         [0003]    It may be desirable to replace multiple capacitors with a single capacitor or different capacitors, or to replace one capacitor with another capacitor that has a different lead configuration, size or shape. If a circuit board has already been manufactured with a specific capacitor or arrangement of multiple capacitors in mind, it is generally difficult to modify the circuit board to accommodate the replacement capacitor. Furthermore, prior to finalizing any decision to employ a replacement capacitor and perhaps redesign the circuit board, testing of the replacement capacitor in the electrical circuit of interest should be conducted. If the replacement capacitor does not correspond to the existing circuit board design, testing may be difficult, and in instances where the circuit is tested for physical integrity, such as high g-force applications, testing may not be possible. 
       SUMMARY OF THE INVENTION 
       [0004]    An adapter is provided to meet the needs and overcome the aforementioned shortcomings in the prior art. The adapter has a plate with an inner face, which is positioned adjacent the circuit board, and an outer face, where a replacement capacitor is affixed. The replacement capacitor has at least two leads, typically representing the anode and the cathode of the capacitor. One or the leads of the capacitor is electrically connected to a first terminal on the adapter plate and the other lead of the capacitor is electrically connect to a second terminal on the adapter plate. The replacement capacitor may have more than two leads, for example, in the case of a concentrically wound, multi-capacitor. In an alternative embodiment, the original capacitors may be replaced with two or more individual capacitors. Accordingly, the adapter is provided with a sufficient number of terminals to electrically connect two or more pairs of leads from the replacement capacitor(s), as needed. 
         [0005]    The terminals of the adapter plate can be provided to accommodate the termination style of the replacement capacitor. By way of example, the terminals may be connected to capacitors having axial leads, radial leads, tabs, screw terminals or snap-in leads. Alternatively, the replacement capacitor may be electrically connected to the terminals of the adapter plate by surface mount technology, such as solder pads provided on the adapter plate. 
         [0006]    The capacitor is affixed to the outer surface of the adapter plate, with sufficient strength to withstand the rigors of testing and operation. By way of example, the capacitor may be affixed with an adhesive, such as a double-sided tape having an adhesive layer bonded to the capacitor case and an opposite adhesive layer bonded to the outer face of the adapter plate. 
         [0007]    The first terminal on the adapter plate is electrically connected via a pathway to the first connector, which has one, two, three or more pins extending downward from the inner face of the plate. The number and arrangement of pins provided by the first connector are selected to engage the circuit board in one or more locations where the original capacitors were located. It can be understood that a single lead of the replacement capacitor is electrically connected to one or more pins, which pins may be arranged to engage the circuit board in approximately the same location as the corresponding leads a the capacitor(s) being replaced. 
         [0008]    The second terminal of the adapter plate is electrically connected via a pathway to the second connector, which has one, two, three or more pins extending downward from the inner face of the plate. The number and arrangement of pins provided by the second connector are selected to engage the circuit board in one or more locations where the original capacitors were located. Accordingly, the second lead of the replacement capacitor is electrically connected to one or more pins, which pins may be arranged to engage the circuit board in approximately the same location as the corresponding leads of capacitor(s) being replaced. 
         [0009]    The present invention also includes a method of replacing one or more capacitors on a circuit board. The method includes providing an adapter, such as the apparatus described above, affixing the replacement capacitor to the outer face of the adapter plate, electrically connecting the leads of the capacitor to the corresponding terminals of the adapter, and electrically connecting the pins of the first connector and the pins of the second connector to the circuit board, at the locations on the circuit board where the capacitor(s) being replaced would have been connected, to achieve the desired current flow. 
         [0010]    The capacitor assembly of the present invention may be connected to the circuit board to replace capacitors connected in parallel, series, or a combination of parallel and series. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a top perspective view of a circuit board showing multiple capacitors connected thereto. 
           [0012]      FIG. 2  is a top perspective view of the circuit board showing the multiple capacitors removed. 
           [0013]      FIG. 3  is a top perspective view of the outer face of the adapter. 
           [0014]      FIG. 4  is a top perspective view of the inner face of the adapter. 
           [0015]      FIG. 5  is a top perspective view of the capacitor assembly having a replacement capacitor affixed to the outer face of the adapter. 
           [0016]      FIG. 6  is an exploded perspective view of the capacitor assembly and circuit board. 
           [0017]      FIG. 7  is a top perspective view of the outer face of an adapter for replacing multiple capacitors connected in series. 
           [0018]      FIG. 8  is a top perspective view of the inner face of an adapter for replacing multiple capacitors connected in series. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Without intending to limit the scope of the invention, the preferred embodiments and features are hereinafter set forth. All United States patents cited in the specification are incorporated herein by reference. 
         [0020]    Referring to  FIGS. 1 and 2 , circuit board  1  has capacitors  2 ,  3  and  4 , having axial leads  2   a  and  2   b ,  3   a  and  3   b  and  4   a  and  4   b , respectively. Leads  2   a ,  3   a  and  4   a  are electrically connected to circuit board  1  at through-holes  7 ,  6  and  5 , respectively. Leads  2   b ,  3   b  and  4   b  are electrically connected to circuit board  1  at through-holes  10 ,  9  and  8 , respectively. By way of example, capacitors  2 ,  3  and  4  are connected in the circuit in parallel. 
         [0021]    Referring to  FIGS. 3 and 4 , adapter  11  has plate  12 , with inner face  13  and outer face  14 . Terminal  15  and terminal  16  are provided for electrically connecting two leads from a replacement capacitor to adapter  11 . Terminals  15  and  16  are shown positioned at end  17  of plate  12 , to accommodate a replacement capacitor having both leads at one end. It can be understood that terminal  15  and  16  may be placed virtually anywhere on plate  12 , for example terminal  15  may be positioned at end  17  and terminal  16  may be positioned at end  18  of plate  12 , to accommodate a replacement capacitor having terminals at opposite ends. 
         [0022]    Adapter  11  has connector  19  having pins  19   a ,  19   b  and  19   c  extending outward from inner face  13  of plate  12 . Connector  19  is electrically connected to terminal  15  by a conductive pathway, such as conductive sheet  20 , embedded in plate  12 . Referring to  FIG. 4 , adapter  11  also has connector  21  having pins  21   a ,  21   b  and  21   c . Connector  21  is electrically connected to terminal  6  by a conductive pathway, such as conductive sheet  22 . Conductive sheet  22  may be partially or completely embedded in plate  12 . Conductive sheet  20  and conductive sheet  22  are electrically insulated from each other, for example, by being inlaid in plate  12  in separate stratum. 
         [0023]    In the example illustrated in  FIGS. 3 and 4 , the pins of one connector, for example  19   a - 19   c , are aligned parallel to the pins of the other connector,  21   a - 21   c , with the two sets of pins being aligned along opposite edges of plate  12 . 
         [0024]    The non-conductive portions of adapter  11  may be any suitable material, for example, epoxy resin. The adapter may be manufactured according to methods known to those skilled in the art, such as printed circuit board and flexible circuit board assembly. A laminate assembly process may be employed, with layering of conductive and non-conductive materials and specific points of entry and exit forming an isolated electric path for the desired current and voltage. 
         [0025]    Referring to  FIG. 5 , capacitor assembly  23  has replacement capacitor  24  affixed to adapter  11  by an adhesive. The adhesive may be double-sided adhesive tape  25  having one side bonded to the outer face  14  of plate  12  and the opposite side of tape  25  is bonded to the underside of capacitor  24 . By way of example, the double-sided tape may be an acrylic foam tape with a pressure activated adhesive. Alternatively, capacitor  24  may be affixed to the outer face  14  of plate  12  by an adhesive used alone or applied to both sides of a different substrate, or by lead frame welding, ultrasonic welding, snap fit or locking tabs or solder bond. Capacitor  24  has leads  26  and  27  electrically connected to terminals  15  and  16 , respectively. In one embodiment of the invention, capacitor assembly  23  is stable up to 30 g-force, or even 80 g-force, as tested according to the military standards in effect on Jan. 1, 2013, namely MIL-STD-202G, Method 204, Test Condition H, Vibration—High Frequency. 
         [0026]    The invention is illustrated with through-holes in the circuit board and pins for the leads extending from the adapter. Alternatively, the connectors extending from the adapter plate may be selected to accommodate the termination style required for the particular circuit board. By way of example, the connectors of the capacitor assembly may be electrically connected to the circuit board by tabs, screw terminals, snap-ins or by soldering or surface mount technology. 
         [0027]      FIG. 6  shows an exploded view of capacitor assembly  23  and circuit board  1 . Pins  19   a ,  19   b  and  19   c  of connector  19  are inserted in through-holes  5 ,  6  and  7  of circuit board  1 , respectively. Likewise, pins  21   a ,  21   b  and  21   c  of connector  21  are inserted in through-holes  8 ,  9  and  10  of circuit board  1 . 
         [0028]    Generally, the function of connectors  19  and  21  is to electrically connect one of the terminals  15  or  16  on plate  12  to each location on circuit board  1  where the leads of one or more capacitors being replaced are located. In the example illustrated in  FIGS. 3-6 , lead  26  of capacitor  24  is electrically connected through terminal  15  and sheet  20  to pins  19   a - 19   c . And, lead  27  of capacitor  24  is connected through terminal  16  and sheet  22  to pins  21   a - 21   c . Accordingly, replacement capacitor  24  can be connected to circuit board  1  in parallel. 
         [0029]    It can be understood that the pins extending from plate  12  can be provided in virtually any configuration to match the number and arrangement of the connections points on circuit board  1 , which represent the capacitors being replaced. For example, the shape of conductive sheets  20  and  22  can be modified so that a pin in a particular location on plate  12  can be connected to either terminal  15  or  16 , depending on the polarity requirements, if any, of the capacitor and circuit board  1 . 
         [0030]    The capacitor assembly of the present invention may be used to replace two or more capacitors connected in series. Referring to  FIGS. 7 and 8 , three individual capacitors connected in series may be replaced by a single capacitor, using the subject adapter. Adapter  30  has plate  31 , inner face  32  and outer face  33 . Terminal  34  can be connected to a first lead of a replacement capacitor and is electrically connected to connector pin  35  via conductive sheet  36 . Pins  37  are not electrically connected, but are provided to secure the assembly to a circuit board. Terminal  38  can be connected to a second lead of a replacement capacitor and is electrically connected to connector pin  39  via conductive sheet  40 . Pins  41  are not electrically connected. 
         [0031]    The present invention is not intended to be limited to a particular type of capacitor. By way of example, suitable replacement capacitors and capacitors that can be replaced include electrolytic capacitors, including aluminum and tantalum capacitors, film capacitors, ceramic capacitors, mica capacitors, and supercapacitors, such as electric double layer capacitors (EDLC), pseudocapacitors and hybrid capacitors. The capacitor may be a multi-capacitor comprised of two or more concentrically wound sections or two or more capacitors within a single housing or multiple housings. The leads can be connected or selected to provide the desired replacement capacitance. The shape of the replacement capacitor may be constrained by the space on the circuit board, but otherwise the shape of the capacitor may be cylindrical, oval or flattened (rectangular prism). The capacitors may range in values from 1 pF to 2 F. 
         [0032]    There are, of course, many alternative embodiments and modifications of the invention, which are intended to be included in the following claims.