Abstract:
A coupler is disclosed that employs hall-effect sensing technology. Specifically, the coupler is configured to produce an output voltage by converting the magnetic field generated by a current conductor at an input side. The output and input sides may be electrically isolated from one another but may be coupled via the hall-effect sensing technology, such as a hall-effect sensor.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The present disclosure is generally directed couplers and specifically those that employ hall-effect sensing technology. 
       BACKGROUND 
       [0002]    Frequently in industrial applications, a high voltage and/or high current system must be monitored to ensure that the electrical power properties of the system meet select criteria, such as remaining within a voltage range, and/or remaining within a current range. Such systems frequently have power variations and fluctuations, such as transients, which can potentially damage sensitive equipment and controllers. 
         [0003]    One solution to problems caused by transients, which is recognized in industry, is gap isolation of the controller via optocouplers, inductance couplers, capacitor couplers, or other gap isolation circuits. 
         [0004]    By way of example, an optocoupler is an electronic device that transfers an electrical signal across an isolation gap by converting the electrical signal to optical light, and back to an electrical signal after passing through an insulation medium. The main objective of optocouplers is to provide high voltage isolation protection on the outside of the circuit, when there is a surge or spike in the voltage rating on the input side. 
         [0005]    A typical optocoupler needs a light source, such as a Light Emitting Device (LED), a photodetector, and an insulation medium. The insulation medium of the optocoupler can be either transparent polyimide or epoxy molding compound that allow optical light to pass through. 
         [0006]    One limitation of existing optocouplers is that they cannot take in the high current directly. Rather, the incoming current is often passed through external resistors to limit the current, thereby increasing the costs associated with implementing the optocoupler. 
         [0007]    Other gap isolators operate similarly with a different type of signal being transmitted across the gap. For instance, an inductance coupler will convert the signal to inductance and then back into an analog electrical signal instead of using an optical signal. While such an arrangement addresses the potential problems caused by a high voltage load in direct connection with a controller, it can give rise to other problems such as scaling factors and the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present disclosure is described in conjunction with the appended figures: 
           [0009]      FIG. 1  is a perspective view of a leadframe and sensor element used for a coupler in accordance with embodiments of the present disclosure; 
           [0010]      FIG. 2  is an exploded perspective view of the components depicted in  FIG. 1 ; 
           [0011]      FIG. 3  is a cross-sectional view of the components depicted in  FIG. 1 ; 
           [0012]      FIG. 4  is a top view of the components depicted in  FIG. 1 ; and 
           [0013]      FIG. 5  is a flow diagram depicting a coupler manufacturing process in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The ensuing description provides embodiments only, and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing the described embodiments. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims. 
         [0015]    As can be seen in  FIGS. 1-4 , a coupling system  100  for use in a coupler will be described. The coupling system  100  may be incorporated into any system which requires current and/or voltage monitoring, but is susceptible to transients. In some embodiments, the coupling system  100  is rated to operate at about 5 kV or more. Stated another way, the coupling system  100  may be incorporated into a coupler and the input of that coupler may directly connected to a 5 kV source without damaging the coupler or its components. Accordingly, the coupling system  100  may be configured to operate in high-voltage or high-current systems. 
         [0016]    Although the coupling system  100  will be described in detail below, it should be appreciated that the coupling system  100  may be incorporated into a coupler by molding or otherwise encapsulating the contents of the coupling system  100  in a plastic as is known in the chip-manufacturing arts. Suitable materials that may be used to mold the coupling system  100  with an and complete the construction of a coupler include, without limitation, plastics or polymers such as polyphthalamide (PPA), silicone, epoxy, any other insulating material, or combinations thereof. 
         [0017]    Referring initially to  FIG. 1 , in some embodiments the coupling system  100  comprises an input side  104  and an output side  108  separated from one another via a gap. The gap between the input side  104  and the output side  108  may be filled with air, gas, liquid, plastic, or any other medium which substantially prevents current from passing directly from the input side  104  to the output side  108 . In other words, the input side  104  is electrically isolated from the output side  108 . The input side  104  may be connected to a circuit whose current and/or voltage is being measured and the output side  108  may be connected to measurement and/or control circuitry. 
         [0018]    Both the input side  104  and output side  108  may be constructed of similar or identical materials. Specifically, the input side  104  and output side  108  and the features of each may be manufactured from a single sheet of metal that is stamped, etched, cut, folded, bent, welded, etc. It should be appreciated that any conductive material may be used for constructing the input side  104  and/or output side  108 , which may collectively be referred to as the leadframe of the coupling system  100 . As some non-limiting examples, the leadframe (e.g., the input side  104  and output side  108 ) may be constructed of metal (e.g. copper, silver, gold, aluminum, etc.), graphite, and/or conductive polymers. It may also be possible that the input side  104  and output side  108  are constructed from different materials. 
         [0019]    In some embodiments, the input side  104  may comprise a first section of the input leadframe  112   a  and a second section of the input leadframe  112   b , each of which has a plurality of pins  116 . In the depicted example, the first and second sections  112   a ,  112   b  may be co-planar to one another. The planar top portion of the first section  112   a  may be connected to one or more pins  116  via a combination of a joint  124  and taper  120 . Additionally, a gap  128  may reside between most of the first section  112   a  and most of the second section  112   b.    
         [0020]    The pins  116 , taper  120 , and shoulder  124  may be collectively referred to as leads. Although embodiments of the present disclosure show the leads as having a specific configuration (e.g., straight-cut leads), it should be appreciated that the leads may comprise any type of known, standardized, or yet-to-be developed configuration such as J leads, SOJ leads, gullwing, reverse gullwing, etc. 
         [0021]    The leads and specifically the pins  116  may be configured to extend away from the first and second sections  112   a ,  112   b . Specifically, where the first and second sections  112   a ,  112   b  are generally planar, the joint  124  between the section  112   a ,  112   b  and a pin  116  may correspond to the feature of the input side  104  where the lead diverges from the plane defined by the sections  112   a ,  112   b . The taper  120  of the lead corresponds to the feature where the lead decreases is size and specifically decreases is cross-sectional area to a size sufficient to be inserted into a Printed Circuit Board (PCB) input or the like. 
         [0022]    The output side  108  may also comprise a plurality of leads that are similar or identical to the leads of the input side  104 . Much like the leads of the input side  104 , each lead of the output side  108  may comprise a pin  136 , a taper  140 , and a joint  144 . The output side  108  may differ from the input side  104  in that the output side  108  may comprise a plurality of sections  132   a ,  132   b ,  132   c ,  132   d , where each section has a dedicated lead. Thus, if the output side  108  comprises four leads as is depicted in  FIG. 1 , then the output side  108  would comprise four sections  132   a ,  132   b ,  132   c ,  132   d . It should be appreciated that the coupling system  100  may comprise a greater or lesser number of leads than those depicted. Specifically, the coupling system  100  depicted herein is intended for use as an 8-pin coupler. Embodiments of the present disclosure contemplate a coupling system  100  having 2 pins, 4 pins, 6 pins, 10 pins, 12 pins, or any other number of pins, whether odd or even. 
         [0023]    A 4-pin coupler would likely comprise a coupling system  100  with two input pins  116  and two output pins  136 . One of the input pins  116  would be connected to the first section  112   a  and the other of the input pits  116  would be connected to the second section  112   b . Similarly, the output side  108  would only comprise a first section  132   a  and a second section  132   b , each having their own dedicated pin  136 . 
         [0024]    Referring back to the depicted embodiment, the sections  132   a ,  132   b ,  132   c ,  132   d  of the output side  108  may be co-planar with the sections  112   a ,  112   b  of the input side  104 . Each section of the output side  108  may be physically and electrically separated from one another in addition to being physically and electrically separated from the input side  104 . As noted above, the relative positions of the input side  104  and output side  108  may be fixed by molding or encapsulating the leadframe in a plastic material. The plastic material may serve the secondary purpose of further electrically insulating the input side  104  from the output side  108  as well as electrically insulating each of the sections  132   a - d  of the output side  108 . 
         [0025]    Because the input side  104  is electrically and physically isolated from the output side  108 , the coupling system  100  may further comprise a sensor assembly  148  that provide a link between the input side  104  and output side  108 . Specifically, the sensor assembly  148  may be configured to detect magnetic fluxes, fields, or the like, created at the input side  104 , convert the magnetic fluxes, fields, etc., into an electrical signal or electrical output and transfer the electrical signal or electrical output to the output side  108  via one or more conductive mechanisms. 
         [0026]    As can be seen in  FIGS. 2 and 4 , current may be configured to flow in a predetermined pattern through the input side  104 . Specifically, the input side  104  may be constructed to force the current to flow in a path according to arrow  220 . In some embodiments, the amount of current which flows through the input side  104  may be anywhere between about 1 A and 150 A. The sensor assembly  148  may be configured to convert the amount of current flowing through the input side  104  into smaller current amounts (e.g., current on the order of micro-amps or milli-amps). Even more specifically, since the input side  104  is configured to force the current flowing therethrough to flow in a curved or circular pattern, the input side  104  causes the flowing current to create a magnetic field as described by the Biot-Savart law or Ampere&#39;s law. This magnetic field is detected by the sensor assembly  148  and converted into an electrical signal (analog or digital) that has a current which is substantially less than the current flowing through the input side  104 . 
         [0027]    Since current generally follows the path of least resistance, the input side  104  is configured with a notch  224  at the terminus of the gap  128 . The notch  124  may comprise a larger width than the gap  128  which causes the current to follow a non-linear path when flowing from the first section  112   a  to the second section  112   b . More specifically, a current-directing feature  228  may be located adjacent to the notch  224  and the current-directing feature  228  may be responsible for carrying current from the first section  112   a  to the second section  112   b . The current-directing feature  228  may be co-planar with the first and second sections  112   a ,  112   b , but may be positioned above the ends of the sections (e.g., further away from the leads of the input side  104  than the ends of the sections  112   a ,  112   b ). Such a configuration of the input side  104  may enable the current flowing through the input side  104  to create a magnetic field that is strong enough to be detected by the sensor assembly  148 . 
         [0028]    With further reference to  FIGS. 2-4 , the sensor assembly  148  is shown to include a number of component parts that enable the sensor assembly  148  to detect a magnetic field and convert the detected magnetic field into an electrical signal that can be transferred to the output side  108 . In some embodiments, the sensor assembly  148  may comprise a sensor carrier  204 , a sensor element  208 , one or more contacts  212 , and an insulator  216 . The sensor carrier  204  may correspond to any substrate made of plastic, ceramic, etc. and the sensor element  208  may correspond to any type of sensor or collection of sensors that is capable of sensing a magnetic field and producing a voltage/current that is proportional to the sensed magnetic field strength. In some embodiments, the sensor element  208  or the entirety of the sensor carrier  204  and sensor element  208  can be miniaturized into a silicon-based semiconductor element. A suitable type of sensor element  208  that may be employed is a hall-effect sensor or hall-sensing silicon Integrated Circuit (IC) chip. Examples of suitable sensor elements  208  and/or sensor assemblies  148  are described in further detail in U.S. Pat. Nos. 7,772,661; 7,042,208; 6,879,145; 5,572,058; 4,931,719; and 4,875,011, each of which are hereby incorporated herein by reference in their entirety. 
         [0029]    As can be seen in  FIGS. 3 and 4 , the sensor assembly  148  may be positioned adjacent, above, or on the leadframe of the input side  104 . In some embodiments, the sensor assembly  148  is mounted or placed on the first section  112   a , the second section  112   b , and the current-directing feature  228 . Even more specifically, the insulator  216  of the sensor assembly  148  may comprise a first major surface and an opposing second major surface. The first major surface of the insulator  216  may be placed on the input side  104  and the second major surface of the insulator  216  may be located adjacent to the sensor carrier  204 . 
         [0030]    The insulator  216 , in some embodiments, is used to enable the coupling system  100  to operate in connection with high input voltages at the input side  104 . As a non-limiting example, the insulator  216  may be constructed of any non-conducting material such as polyimide, PPA, or any other type of polymer. The insulator  216  provides a physical separation between the current conductor (e.g., the leadframe of the input side  104 ) and the silicon (e.g., the sensor carrier  204  and/or sensor element  208 ). The insulator  216  is a layer that may be used to provide the high-voltage isolation between the sensor carrier  204  and/or sensor element  208  and the current flowing through the leadframe. The insulator  216  may also operate as an adhesive layer to attach the sensor carrier  204  and/or sensor element  208  onto the leadframe  104  of the input side  104 . 
         [0031]    The overall construction of the coupling system  100  and specifically the sensor assembly  148  may be designed to avoid electrically bridging the input side  104  to the output side  108 , as this will compromise the internal creepage, thereby resulting in a high-voltage failure of the coupling system  100 . In some embodiments, the thickness of the insulator  216  may be about 2 mils or greater. Where the surface area of the insulator  216  coincides with the surface area of the sensor carrier  204 , the thickness of the insulator  216  may be 3 mils or greater to achieve a 5 kV rating for the coupling system  100 . It should be appreciated that even larger thicknesses of an insulator  216  may be employed, but would result in an increased size of the coupling system  100 . It may be possible that the thickness of the insulator  216  is larger than the thickness of the sensor carrier  204 . 
         [0032]    As can be seen in  FIGS. 3 and 4 , the sensor assembly  148  may overhang or extend further than the leadframe of the input side  104 . Specifically, a leadframe isolation gap  308  may be defined as the minimum distance between the input side  104  and the output side  108 . In some embodiments, the sensor assembly  148  may be positioned on the input side  104  so as to hang over or partially cover some of the leadframe isolation gap  308 . The minimum distance between the leadframe assembly  148  and the output side  108  may be referred to as a sensor-output gap  312 , which may be smaller than the leadframe isolation gap  308 . In some embodiments, the sensor-output gap  312  may have a dimension of at least about 10 mils to achieve a 5 kV rating for the coupling system  100 . 
         [0033]      FIG. 3  also depicts a wire  304  that may be used to carry current from a contact  212  of the sensor assembly  148  to an output section  132   a ,  132   b ,  132   c ,  132   d . The wire  304  may be constructed of any known type of conductive material or collection of conductive materials. In the depicted embodiment, the sensor assembly  148  has four contacts  212 , where each contact may be connected to a different output section  132   a - d  by a different piece of wire  304 . It should be noted that the number of contacts  212  does not necessarily have to equal the number of output sections  132 . There may be a greater number of contacts  212  than output sections  132  or vice versa. Likewise, not every contact  212  has to be connected to an output section  132  or vice versa. 
         [0034]    As can be seen in  FIG. 4 , one or more of the output sections  132   a - d  may comprise an arm  404  or similar feature which extends toward the contacts  212  of the sensor assembly  148 . By providing the arm  404  on the output section  132 , the amount of wire  404  that is required to connect the contact  212  to the output section  132  can be reduced, thereby reducing the likelihood of failure by virtue of the wire becoming broken or disconnected. 
         [0035]    The relative position of the sensor element  208  and the notch  224  can also be seen in further detail in  FIG. 4 . Specifically, it may be desirable to position the sensor element  208  directly above the notch  224  or at some location where the magnetic field produced by the current flowing through the current-directing element  228  is the strongest. By positioning the sensor element  208  at such a location, the accuracy of the coupling system  100  can be increased and/or a less sensitive sensor element  208  can be employed, thereby resulting in a most cost-effective coupling system  100 . 
         [0036]    With reference now to  FIG. 5 , one example of a method for constructing a coupler which incorporates the coupling system  100  will be described in accordance with embodiments of the present disclosure. The method is initiated with the construction of the leadframe (step  504 ). As noted above, both the input side  104  and output side  108  of the leadframe may be constructed simultaneously from a single sheet of metal. 
         [0037]    Thereafter, the insulator  216  is positioned relative to the current-directing feature  228  or some other component of the input side  104  (step  508 ). The sensor element  208  and/or sensor carrier  204  may then be positioned on the insulator  216  such that the sensor element  208  is at an optimal position for detecting magnetic fields produced by current flowing through the current-directing feature  228  (step  512 ). It should be noted that steps  508  and  512  may be performed simultaneously. 
         [0038]    Thereafter, the sensor assembly  148  may be electrically connected to the output side  108  via one or more wires  304  and then the entire coupling system  100  may be molded or otherwise have the relative positions of the component parts of the coupling system  100  fixed. In particular, the sensor assembly  148  may be secured to the leadframe and the wires connecting the sensor assembly  148  to the output side  108  of the leadframe may be encapsulated or molded in a plastic or epoxy (step  516 ). Any further steps required to complete the construction of the coupler may then be taken such as bending the leads of the leadframe, removing excess plastic from the mold which now encases the leadframe and sensor assembly  148 , and so on (step  520 ). 
         [0039]    Specific details were given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. 
         [0040]    While illustrative embodiments of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.