Abstract:
A charging system that comprises circuitry adapted to devices to be charged, including a power receiver module embedded in or molded into a form-fit case, e.g., gel-skin, that attaches physically and electrically to the device to be charged and that effectively receives power conductively from a power delivery surface of a recharging pad on which the devices are placed. An embodiment may include a method or device whereby a simplified, common interface provides power to mobile devices via electrical contact for a range of positions and orientations of the mobile device. In some embodiments, the range of positions may be automatically partially constrained mechanically such that power is transferred for all possible remaining orientations.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a non-provisional application based upon and claims priority to U.S. provisional application Ser. No. 61/033,223 filed Mar. 3, 2008, entitled “Universal Electrical Interface for Providing Power to Mobile Devices,” which is specifically incorporated herein by reference for all that it discloses and teaches. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to electronic systems and methods for providing electrical power and/or data to one or more electronic or electrically powered devices with a power delivery surface. 
         [0004]    2. State of the Prior Art 
         [0005]    A variety of electronic or electrically powered devices, such as toys, game devices, cell phones, laptop computers, cameras, and personal digital assistants, have been developed along with ways for powering them. Mobile electronic devices typically include, and are powered by, batteries, which are rechargeable by connecting the batteries through power cord units to a power source. Power cord units typically include transformers and/or power converters connected to a power source such that the transformers and/or power converters condition the power supplied to the mobile electronic device. Typical power sources include, but are not limited to, an electric wall outlet, a connection to the power grid, and/or an automobile or other vehicle accessory electric outlet plug receptacle or the like. A mobile electronic device may typically be connected to the power source through the power cord unit either during use of the electronic device and/or between uses. A non-mobile electronic device is generally one that is powered through a power cord unit and is not intended to be moved during use any farther than the reach of the power cord, so the non-mobile electronic device generally does not have, or need, batteries for powering the device between plug-ins to the power source. 
         [0006]    In a typical set-up for a mobile device, the power cord unit includes an outlet connector or plug for connecting it to the power source and a battery connector for connecting it to a corresponding battery power receptacle of the battery. The outlet connector or plug and battery connectors are typically in connected with each other such that electrical power may flow from the power source to the battery, and in some limited instances from the battery to the power source. The power source charges the battery through the power cord unit via the electrical connection between the power source and the battery. 
         [0007]    In some setups, the power cord unit may include a power adapter, transformer, or converter connected to the outlet and battery connectors through AC (Alternating Current) input and DC (Direct Current) output cords, respectively. The power adapter typically adapts an AC input voltage received from the power source through the outlet connector and AC input cord to output a DC voltage through the DC output cord. Other setups include adapters, transformers, or converters connected to the outlet and battery connectors through DC input and DC output cords. The DC output current flows through the battery power receptacle and is used to charge the battery. 
         [0008]    Manufacturers, however, many times make their own models of electronic devices and do not make their power cord unit compatible with the electronic devices of other manufacturers, or with other types of electronic devices. As a result, a battery connector made by one manufacturer may not fit into the battery power receptacle made by another manufacturer. Further, a battery connector made for one type of device typically will not fit into the battery power receptacle made for another type of device. Further, even in instances where interchangeable connectors are used by different manufacturers, the electrical characteristics/power requirements may differ from other manufacturers devices, such as having different DC input voltages required at the battery power receptacle. Manufacturers make the power cord unit connectors unique to their own devices for several reasons, such as cost, liability concerns, different power requirements, and to acquire or hold a market share. 
         [0009]    However, the proliferation of unique power cords that are not compatible with other devices can be troublesome for consumers because they have to buy unique power cord units for their particular electronic devices and deal with the plethora of different power cords required for their devices. Since people tend to switch devices often, it is inconvenient, expensive, and wasteful for them to also have to switch power cord units as well. Unfortunately, power cord units that are no longer useful are often discarded, which is also wasteful and harmful to the environment. Further, people generally own a number of different types of electronic devices and owning a power cord unit for each device is inconvenient because the consumer must deal with a large quantity of power cord units and the confusion and tangle of power cords the situation creates. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings, which are incorporated in and form a part of the specification, illustrate example implementations of the present invention, but not the only ways the invention can be implemented, and together with the written description and claims, serve to explain the principles of the invention. 
           [0011]    In the drawings: 
           [0012]      FIG. 1  is a perspective view of a wireless charging pad and a mobile device being placed on the wireless charging pad. 
           [0013]      FIG. 2  is an enlarged perspective view of a wireless charging pad showing an array of alternately positively and negatively charged contact strips. 
           [0014]      FIG. 3  is an enlarged bottom view of an enabled mobile device showing multiple contact points arranged in a contact pattern. 
           [0015]      FIG. 4  is a schematic diagram of a four-way bridge rectifier for properly obtaining the correct electrical connection for a mobile device with four contact points. 
           [0016]      FIG. 5  is a block diagram of a charging system having a wireless charging pad with alternating conducting strips and a mobile device with many contact points arranged in a contact pattern. 
           [0017]      FIG. 6  is a perspective view of a simplified wireless power interface embodiment that uses partial mechanical constraints to orient a mobile device. 
           [0018]      FIG. 7  is a bottom view of an example power receiving device with two contact points for connection to a simplified wireless power interface. 
           [0019]      FIG. 8  is a side view of a mobile device resting on a simplified wireless power interface support surface. 
           [0020]      FIG. 9  is a schematic diagram of a simple circuit for deriving power from a simplified wireless power interface. 
           [0021]      FIG. 10  is a schematic diagram of a safety circuit for protecting a mobile device deriving power from a simplified wireless power interface. 
           [0022]      FIG. 11  is a block diagram of a power transfer system (i.e., charging system) using a simplified wireless power interface. 
           [0023]      FIG. 12  is a perspective view of an embodiment of a support surface for a simplified wireless power interface. 
           [0024]      FIG. 13  is a schematic diagram of a circuit to protect a mobile device using a simplified wireless power interface from a reverse polarity electrical connection to the simplified wireless power interface. 
           [0025]      FIG. 14  is a schematic diagram of a circuit to protect a mobile device using a simplified wireless power interface from a reverse polarity electrical connection to the simplified wireless power interface using a shunt diode. 
           [0026]      FIG. 15  is a schematic diagram of a bridge rectifier circuit to increase orientation tolerance of a mobile device using a simplified wireless power interface to nearly 360 degrees. 
           [0027]      FIG. 16  is a perspective view of an embodiment of a support surface for a simplified wireless power interface including magnets to assist in mobile device orientation. 
           [0028]      FIG. 17  is a bottom view of an embodiment of a mobile device for use with a simplified power interface that includes magnets to assist in mobile device orientation. 
           [0029]      FIG. 18  is a perspective view of an embodiment of a support surface for a simplified wireless power interface including magnets to assist in mobile device orientation and a third electrode strip to provide unique polarity regardless of mobile device orientation. 
           [0030]      FIG. 19  is a bottom view of an embodiment of a mobile device for use with a simplified power interface that includes magnets to assist in mobile device orientation and a third electrode strip to provide unique polarity regardless of orientation. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0031]    An embodiment may include a method or device whereby a simplified, common interface provides power to mobile devices via electrical contact for a range of positions and orientations of the mobile device. In some embodiments, the range of positions may be automatically partially constrained mechanically such that power is transferred for all possible remaining orientations. 
         [0032]      FIG. 1  is a perspective view of a wireless charging pad  100  and a mobile device  108  being placed  116  on the wireless charging pad  100 . The wireless charging pad  100  receives power from a power source  102 . The ultimate power source may be any available electrical power source including AC and DC power sources. Either at the charging pad  100  or before electrical power is received  102  at the charging pad  100 , the power may be conditioned to meet the electrical requirements of the charging pad  100 . One skilled in the art is capable of defining the proper electrical requirements for the charging pad  100  to charge desired mobile devices  108 . The charging pad  100  has a surface support structure  104  containing an array of conductors  106  intended to make electrical contact with the contact points  112  on the bottom  110  of the mobile device  108 . The array of conductors  106  may be arranged in an alternating pattern of positive and negative charged conductors (see disclosure with respect to  FIG. 2 ). The bottom  110  of the mobile device  108  has many contact points  112  arranged in a pattern  114 . The mobile device  108  is typically considered to be mobile, but may be any device  108  with a battery that requires charging, even if the device is not considered to be mobile. 
         [0033]      FIG. 2  is an enlarged perspective view of a wireless charging pad  100  showing an array  106  of alternately positively  204  and negatively  202  charged contact strips  106 . The wireless charging pad  100  of  FIG. 2  is similar to the wireless charging pad  100  of  FIG. 1 . Thus, the wireless charging pad  100  is supplied power  102  to an array of conductors  106  for use to charge a mobile electronic device  108 . The mobile electronic device makes contact with the support surface  104  of the wireless charging pad  100 . The support surface  104  of the wireless charging pad  100  exposes the array of conductors  106  to the contact points  112  of the mobile device  108 . There need to be a sufficient number of contact points  112  on the mobile device  108  arranged in a pattern  114  to ensure that at least one contact point  112  has an electrical connection with a negatively charged conductor strip  202  and at least a second contact has an electrical connection with a positively charged conductor strip  204 . The mobile device  108  may need many contact points  112  to ensure proper electrical connection to the conductor array  106  of the wireless charging pad  100 . As shown, the mobile device  108  has four contact points  112 . Some embodiments may require five or more contact points  112  to ensure proper electrical connection between the mobile device  108  and the charging pad  100 . 
         [0034]      FIG. 3  is an enlarged bottom  110  view of an enabled mobile device  108  showing multiple contact points  112  arranged in a contact pattern  114 . As shown, there are four contact points  112  arranged in pattern  114 . The mobile device  108  of  FIG. 3  may be charged by placement on the support surface  104  of the charging pad  100  described in the disclosure with respect to  FIGS. 1 and 2 . 
         [0035]      FIG. 4  is a schematic diagram of a four-way bridge rectifier  400  for properly obtaining the correct electrical connection for a mobile device  108  with four contact points  112 . Contact points A  402 , B  404 , C  406 , and D  408  correspond to the four contact points  112  on the mobile device  108 . The four contact points  402 - 408  are electrically connected as shown to a positive electrical node  410  through Zener diodes  402 ′- 408 ′, respectively. The four contact points  402 - 408  are also electrically connected as shown to a negative/ground electrical node  412  through Zener diodes  402 ″- 408 ″, respectively. The bridge rectifier  400  is electrically designed to ensure that a contact point  402 - 408  contacting a positive conductor  204  is properly shunted to the positive node  410  and a contact point  402 - 408  contacting a negative conductor  202  is properly shunted to the negative/ground node  412 . One skilled in the art will recognize that other rectifier circuits and other control circuitry may be utilized to ensure proper electrical connection of the contact points  402 - 408  as is achieved with the bridge rectifier  400  shown. 
         [0036]      FIG. 5  is a block diagram of a charging system having a wireless charging pad  100  with alternating conducting strips  106  and a mobile device  108  with many contact points  112  arranged in a contact pattern  114 . In the system shown in  FIG. 5 , the AC adapter  504  is plugged into a wall plug  502 . The AC adapter  504  connects to control and safety circuitry  506  which then electrically powers the support surface with an electrode/conductor pattern  508 . The mobile device  510  has contact points to pickup  512  an electrical power supply from the conductors on the support surface  508 . The pickup  512  of the mobile device  510  passes the electrical connection through a rectifier  514 , such as the bridge rectifier  400  described in the disclosure with respect to  FIG. 4 . The rectifier  514  output goes through power conditioning circuitry  516  and ultimately delivers power to the target device  518 . 
         [0037]    The charging pad  100  and mobile device  108  described in the disclosure with respect to  FIGS. 1-5  provides for a universal interface for mobile electronic devices  108  such that the devices  108  may be positioned at any position and orientation upon a support surface  104  of electrodes  106 . To allow for ambiguity in alignment of the contact points  112  of the mobile device  108  yet still deliver power, a particular pattern  114  of contacts  112  or a large number of contacts  112  (five or more) may be required on the mobile device  108 . Each of the contacts  112  is connected to one leg of a bridge rectifier  400  in order to account for the ambiguity in polarity that each of the contacts  112  may provide depending on the position and orientation of the mobile device  108  upon the support surface  104  of electrodes  106 . The bridge rectifier  400  may increase the complexity, cost, and inefficiency of the charging system. 
         [0038]    The technology of the charging pad  100  and mobile device system  108  is termed conductive in that the charging system relies on physical contact between a set of conductors  106  on a surface  104  with alternating polarity, and a set of contacts  112  on a device  108  resting on the surface  104 . Power may be obtained within the device  108  by rectifying the arbitrary polarity found at each contact point  112  as described in the disclosure with respect to  FIG. 4 . 
         [0039]    Power is extracted from the surface  104  of the pad  100  through two or more of the contacts  112  on the device  108 . Electrical contact may be accomplished via a simple bridge rectifier as shown in  FIG. 4 . 
         [0040]    For the charging pad  100 /device  108  charging system described in the disclosure with respect to  FIGS. 1-5 , other patterns of electrodes  106  and contact points  112  are possible to attain power transfer regardless of device  108  position and orientation on the support surface  104  of electrodes  106 . The charging system of  FIGS. 1-5  is designed to be broadly applicable and, therefore, typically uses a nominal potential of 15V. Since many mobile devices are designed to be charged through ubiquitous USB (Universal Serial Bus) ports, which typically requires 5V. Thus, a voltage converter may be necessary in the charging system of  FIGS. 1-5  for many mobile devices in order to step down the voltage appropriately. The disclosure with respect to the block diagram of  FIG. 5  describes a typical application. 
         [0041]    An embodiment may provide an interface in which the device alignment is partially mechanically constrained or in which the power transfer is guaranteed for a subset of all possible positions and orientations of devices. For a system with partial mechanical constraints of the charging devices, the number of contacts that are required on the mobile device may be reduced, thus, reducing the complexity of the rectifier circuit. In some embodiments the rectifier may be completely removed. Further a system that is more appropriate for a wide range of mobile devices that require 5V input potential may also be beneficial. 
         [0042]      FIG. 6  is a perspective view of a simplified wireless power interface embodiment  600  that uses partial mechanical constraints to orient a mobile device. The embodiment of a simplified universal power interface  600  shown in  FIG. 6  has an support surface  602  mounted vertically or nearly vertically so that a device  700  (see the disclosure with respect to  FIG. 7 ) that rests on the simplified wireless power interface  600  will tend to slide down due to the force of gravity. A mechanical rest shelf  608  extends outward along the bottom edge of the support surface  608 . A mobile device  700  may, therefore, rest against the support surface  608  and be simultaneously aligned to rest against the rest shelf  608 . Accordingly, the positions of the electrical contacts  708  (see the disclosure with respect to  FIG. 7 ) on the mobile device  700  are aligned to a predetermined position with respect to the support surface  608  such that the electrical contacts  708  make contact with electrode strip A  604  and electrode strip B  606 . 
         [0043]      FIG. 7  is a bottom  702  view of an example power receiving device  700  with two contact points  708  for connection to a simplified wireless power interface  600 . The mobile device  700  may be configured with two contact points  708  as shown instead of the 4 or more described in the disclosure with respect to  FIGS. 1-5 . Depending on the protection circuitry, or lack thereof, the contact points  708  may be polarity sensitive. That is, contact point A  704  may only function properly when in contact with electrode A  604  and contact point B  706  may only function properly when in contact with electrode B  708 . A bridge rectifier  400  as described in the disclosure with respect to  FIG. 4  may alleviate the polarity problem at an increase in system component cost as compared to a polarity sensitive solution (see also the disclosure with respect to  FIG. 15 ). 
         [0044]      FIG. 8  is a side view of a mobile device  700  resting on a simplified wireless power interface support surface  600 . When the mobile device  700  rests against the support surface  602  and is then positioned via gravity (or some other force) against the rest shelf  608 , contacts A  704  and B  706  are at predetermined distances with respect to the support surface  602  and the rest shelf  608 . Ideally, the predetermined distance corresponds to the point midway up the width of electrode strips A  604  and B  606  such that electrical contact is made between electrode strips A  604  and B  606  and contact points A  704  and B  706  as shown in  FIG. 8 . 
         [0045]    Due to the mechanical constraint of the rest shelf  608  and the placement of the contact points  708  on the mobile device  700 , it may be guaranteed that when the charging circuit is closed between the support surface electrodes  604 ,  606  and the mobile device contacts  704 ,  706 , the polarity is as expected. As one skilled in the art may understand, by placing the contact points  708  on an end of a device, it may be mechanically guaranteed that contact A  704  and contact B  706  may not contact either electrode strip A  604  or electrode strip B except in a single orientation as the contact points  708  would be above the electrode strips  604 ,  606  when the device  700  is positioned upside down or on either side with respect to the rest shelf  608 . In other words, the mechanical constraint may insure that contact A  704  connects to electrode A  604 , and contact B  706  connects to electrode B  606 . Due to the mechanical constraint, the need for a bridge rectifier, such as those shown in  FIGS. 4 and 15 , is unnecessary and a simple connection such as the connection described in the disclosure with respect to  FIG. 9  may be utilized with a corresponding reduction in overall component costs. 
         [0046]    Various embodiments may permit several devices  700  side-by-side to simultaneously acquire power from the power delivery surface  602 . Thus delivering a convenient wireless power system. 
         [0047]      FIG. 9  is a schematic diagram of a simple circuit  900  for deriving power from a simplified wireless power interface  600 . A mobile device  700  designed to charge on a mechanically constrained simplified wireless power interface  600  may forgo polarity correction or protection due to the mechanical constraints  608 ,  708  that ensure proper polarity connection between the device  700  and the simplified wireless power interface  600 . Thus, an embodiment  900  may connect contact A  704  to the positive battery terminal  904  and contact B  706  to the negative/ground battery terminal  906 . 
         [0048]      FIG. 10  is a schematic diagram of a safety circuit  1000  for protecting a mobile device  700  deriving power from a simplified wireless power interface  600 . The safety circuit  1000  may be used to accommodate a safety protected support surface  602 . The safety protected support surface  602  may temporarily remove the electrical potential (i.e., voltage) from the surface  602  electrodes  604 ,  608 . During the time the electrical potential is removed from surface  602  electrodes  604 ,  608 , the power receiver in the mobile device  700  may need to have a small amount of storage capacitance  1010  to sustain the internally available mobile device  700  power supply electrical potential. As shown, the safety circuit  1000  places a Zener diode  1008  between contact point A  704  and the positive battery terminal  1004 . Contact point B  706  is connected to the negative/ground battery terminal  1006 . A capacitor  1010  is placed between the positive terminal  1004  and the ground terminal  1006 . The safety circuit  1000  has the added benefit of preventing power from inadvertently being applied in the reverse direction (i.e., reverse polarity) such as may be done with a readily available 9V primary cell. The Zener diode  1008  protects against a closed circuit in a reverse polarity situation. The capacitor  1010  sustains the internally available mobile device  700  power supply electrical potential as described above. One skilled in the art will recognize that other circuits and other control circuitry may be utilized to protect against reverse polarity and/or to provide voltage support as is achieved with the safety circuit  1000  shown. 
         [0049]      FIG. 11  is a block diagram of a power transfer system (i.e., charging system) using a simplified wireless power interface. A simplified support surface power supply  1108  may be implemented according to the disclosure with respect to  FIGS. 6-10 . To support USB compatible devices with minimal additional circuitry, the power supply voltage may be set to 5V with current limiting. The electrical potential (i.e., voltage) is so low as to be typically undetectable by a human. Further, current limiting may be considered a sufficient safety measure. Accordingly, the block diagram shown in  FIG. 11  assumes 5V with current limiting for the support surface  1108  power supply. 
         [0050]    In the block diagram of  FIG. 11 , the AC adapter  1104  is connected to a wall plug  1102 . The AC adapter delivers 5V DC power to the support surface with electrode patterns  1108  as described in the disclosure with respect to  FIGS. 6-10 . The mobile device  1110  uses the two contact points ( 708 ) as the pickup  1112  for the electrical power. The pickup  1112  delivers power to the target device  1118  without the need for intervening circuitry (see the disclosure with respect to  FIG. 9 ) or with minimal protective circuitry (see the disclosure with respect to  FIG. 10 ). 
         [0051]      FIG. 12  is a perspective view of an embodiment of a support surface  1202  for a simplified wireless power interface  1200 . For the embodiment  1200  shown in  FIG. 12 , a predetermined position and/or orientation of the mobile device  700  with respect to the support surface  1202  is assumed to be known to a user that is familiar with the orientation necessary for power transfer with the simplified wireless power interface  1200 . When power transfer is desired, the user places the mobile device  700  on the support surface  1202  in a particular orientation and at a particular position as designated for power transfer between the support surface  1202  and the mobile device  700  via connection with electrode strip A  1204  and electrode strip B  1206  as described above for embodiments such as the embodiment  600  described in the disclosure with respect to  FIG. 6 . A practical design would allow for considerable positioning and orientation tolerance so that a typical user could readily arrange for power to be transferred. One skilled in the art may determine many orientation systems that may affectively provide an orientation known to a user for a mobile device  700  to be properly placed on the support surface  1202 . 
         [0052]    For instance, for an embodiment of a wireless power delivery system  1200  relying upon a predetermined range of orientations and positions of the mobile device  700  may have two strips of conductor electrodes  1204 ,  1206  on the support surface  1202  arranged such that the length of the conductor electrodes  1204 ,  1206  runs parallel to an X axis  1212  and perpendicular to a Y axis  1210 . A mobile device  700 , such as that shown in  FIG. 7 , with two contacts A  704  and B  706  on the back may derive power from the support surface  1202  provided that the mobile device  700  was roughly aligned parallel to the Y axis  1210  as shown, and roughly centered on the electrode strips  1204 ,  1206 . The support surface  32 ′ may accommodate and power one or more additional mobile devices  700  set side-by-side with the first device  700 , provided the additional devices were also aligned as described since the position along the X axis  1212  does not affect power transfer (so long as the mobile device rests on the support surface). It is possible that a user may place a mobile device  700  on the support surface  1200  aligned substantially 180 degrees from the desired orientation. In that case, power could inadvertently be applied to the mobile device  700  with reverse polarity. 
         [0053]      FIG. 13  is a schematic diagram of a circuit  1300  to protect a mobile device  700  using a simplified wireless power interface  1200  (also applicable for other embodiments of the simplified wireless power interface, including  600  shown on  FIG. 6 ,  1600  shown on  FIG. 16 , and  1800  shown on  FIG. 18 ) from a reverse polarity electrical connection to the simplified wireless power interface  1200 . The circuit  1300  may be used to prevent damage to the mobile device  700 . The circuit  1300  connects contact A  704  to the positive battery terminal  1304  through Zener diode  1308 . Contact B  706  is connected to the negative/ground battery terminal  1306 . One skilled in the art will recognize that other circuits and other control circuitry may be utilized to protect against reverse polarity as is achieved with the safety circuit  1300  shown. 
         [0054]      FIG. 14  is a schematic diagram of a circuit  1400  to protect a mobile device using a simplified wireless power interface  1200  (also applicable for other embodiments of the simplified wireless power interface, including  600  shown on  FIG. 6 ,  1600  shown on  FIG. 16 , and  1800  shown on  FIG. 18 ) from a reverse polarity electrical connection to the simplified wireless power interface  1200  using a shunt diode  1408 . As with circuit  1300  shown in  FIG. 13 , circuit  1400  shown in  FIG. 14  may be used to prevent damage to the mobile device  700  provided the diode is able to withstand the short circuit current available from the power delivery surface  1202  electrodes  1204 ,  1206 . 
         [0055]    In the best case with the either circuit  1300  or  1400  of  FIG. 13  or  14 , respectively, the mobile device  700  may receive power from the support surface  1202  for orientation angles of almost +/−90 degrees with respect to the Y axis  1210 . To be clear, it is defined that zero degrees with respect to the Y axis  1210  would represent the case when the line defined by the two contact points  704 ,  706  is parallel to the Y axis  1210 . Accordingly, 90 degrees would correspond to the line defined by the two contact points being parallel to the X axis  1212 . The rotation being considered is that in the X-Y plane. 
         [0056]      FIG. 15  is a schematic diagram of a bridge rectifier circuit  1500  to increase orientation tolerance of a mobile device  700  using a simplified wireless power interface  1200  to nearly 360 degrees. As with circuits  1300  of  FIGS. 13 and 1400  of  FIG. 14 , the bridge rectifier circuit  1500  may also be applied with to other embodiments of the simplified wireless power interface, including  600  shown on  FIG. 6 ,  1600  shown on  FIG. 16 , and  1800  shown on  FIG. 18 . With a slightly more complex circuit  1500  in the mobile device  700 , the range of orientations may be increased to almost 360 degrees. A nearly 360 degree rotation is achieved because if the device  700  is placed substantially “upside down”—or oriented at an angle of 180 degrees +/−90 degrees, then the effect is to reverse the polarity of the potential expected on contacts A  704  and B  706 . The bridge rectifier  1500  of  FIG. 15  rectifies the polarity to handle the reversed polarity. The nearly 360 rotation is a function of the necessity that the two contacts  704 ,  706  need to be contacting different conductor electrodes  1204 ,  1206  from each other. One skilled in the art will recognize that other circuits and other control circuitry may be utilized to overcome reverse polarity as is achieved with the bridge rectifier circuit  1500  shown. 
         [0057]    An embodiment with a bridge rectifier  1500  provides a wireless power delivery system  1200  that is relatively tolerant to a range of positions and orientations but cannot guarantee power delivery at all positions and orientations. Some tolerance is given up in exchange for a considerably simplified overall system. The tradeoff is minimized by the user assumption of a proper orientation and position. 
         [0058]      FIG. 16  is a perspective view of an embodiment of a support surface  1602  for a simplified wireless power interface  1600  including magnets  1620  to assist in mobile device  1700  orientation (see the disclosure with respect to  FIG. 17 ). For an embodiment  1600 , mechanical positioning is “softly” constrained via the use of magnets. An embodiment  1600  may have magnets  1620  (shown in phantom lines) arranged along the centerline of the gap between the electrode strips  1604 ,  1606 . The magnets  1620  may be equally spaced a predetermined distance apart and the polarity of the magnets may be aligned in the same direction along the Z axis  1614 . An embodiment  1600  may have magnets  1620  placed in the mobile device  1700  as shown in  FIG. 17 . 
         [0059]      FIG. 17  is a bottom  1702  view of an embodiment of a mobile device  1700  for use with a simplified power interface  1600  that includes magnets  1620 ,  1720  to assist in mobile device  1700  orientation. The polarity of the magnets  1720  in the mobile device  1700  are also aligned in the same direction as the magnets  1620  on the simplified power interface  1600  and in such a way that they attract the magnets  1620  on the support surface  1602  when the contacts  1704 ,  1706  are facing the electrode strips  1604 ,  1606 . The spacing between magnets  1720  on the mobile device  1720  matches the spacing of the magnets  1620  embedded within the support surface  1602 . Depending on the location of magnets  1720  with relation to contacts  1704 ,  1706 , the magnets  1620  may be located at the centerline between electrodes  1604 ,  1606  or elsewhere on or under the support surface  1602  as appropriate for the configuration of the magnets  1720  and contacts  1704 ,  1706  of the mobile device  1700 . Further, more than two magnets may be used in the mobile device, but having at least two magnets permits proper orientation to a line (i.e., a line is defined by two points). 
         [0060]    The magnet-to-magnet force is sufficient that if the mobile device  1700  were placed relatively near the desired position, the mobile device  1700  would be pulled into alignment with the two nearest magnets  1620 . When engaged in this orientation the contact points  1704 ,  1706  would also make an electrical connection to the electrode strips  1604 ,  1606 , thereby closing a circuit to allow power flow. 
         [0061]    It is evident that in an embodiment of the simplified wireless power interface  1600  and mobile device  1700 , the mobile device  1700  will seek one of two possible orientations denoted by zero degrees with respect to the Y axis  1610  and 180 degrees with respect to the Y axis  1610 . The two orientation configurations correspond to two different voltage polarities. Therefore, it is prudent that the electrical circuit within the mobile device  1700  be protected against reverse polarity as may be accomplished via the circuits of  FIG. 13 ,  14 , or  15  ( 1300 ,  1400 ,  1500 , respectively) as well as other possible circuits as may be recognized by one skilled in the art. Again, multiple devices  1700  may be aligned along the X axis  1612 . 
         [0062]      FIG. 18  is a perspective view of an embodiment of a support surface  1802  for a simplified wireless power interface  1800  including magnets  1820  to assist in mobile device  1900  orientation (see the disclosure with respect to  FIG. 19 ) and a third electrode strip  1808  to provide unique polarity regardless of mobile device  1900  orientation. The magnets  1820  and devices  1900  may be aligned with the X axis  1812 , Y axis  1810 , and Z axis  1814  in a similar fashion as for the disclosure the embodiment  1600  described in the disclosure with respect to  FIGS. 16 and 17 . 
         [0063]      FIG. 19  is a bottom  1902  view of an embodiment of a mobile device  1900  for use with a simplified power interface  1800  that includes magnets  1820 ,  1920  to assist in mobile device orientation and a third electrode strip  1808  to provide unique polarity regardless of orientation. 
         [0064]    For the embodiment  1800 , either of two possible orientations corresponds to a single voltage polarization. For the embodiment  1800 , contact A  1904  located on the mobile device  1900  will seek electrode strip B  1806  located on the support surface  1802 . Contact B  1906  on the mobile device  1900  will seek electrode strip A or C ( 1804  or  1808 , respectively) on the support surface  1802 . Since electrode A and C ( 1804  and  1808 , respectively) are at the same potential, the resulting potential on contacts A  1904  and B  1906  will remain the same. 
         [0065]    Since magnetic alignment is “soft,” meaning that magnetic alignment is a constraint that may be overcome with minimal force, there is still a possibility that contacts A  1904  and B  1906  will come into the various electrode strips  1804 ,  1806 ,  1808  on the support surface  1802  in such a way as to cause a reverse polarity condition within the mobile device  1900 . Thus, protection such as afforded by the circuit of  FIG. 13 ,  14 , or  15  ( 1300 ,  1400 , or  1500 , respectively), is prudent. Again, one skilled in the art may recognize other possible circuits to provide similar protection as those discussed herein. 
         [0066]    The benefit of the embodiment  1800 ,  1900  is that the required protection circuit may be simplified at the expense of an additional electrode strip  1808 , and in the case of the circuit  1400  of  FIG. 14 , no loss occurs due to the circuit  1400 . The use of a rectifier circuit  1500  may be unnecessary with the use of the additional electrode strip  1808 . The embodiment  1800 ,  1900  provides the highest possible efficiency while still providing a simple, easy to position wireless power experience. 
         [0067]    The foregoing description is considered as illustrative of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and process shown and described above. Accordingly, resort may be made to all suitable modifications and equivalents that fall within the scope of the invention. The words “comprise,” “comprises,” “comprising,” “include,” “including,” and “includes” when used in this specification are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, or groups thereof.