PATENT DOCUMENT

Publication Number: US-11159047-B2
Application Number: US-201916554349-A
Country: US
Kind Code: B2

Title: Thermally optimized RX wireless charger for small RX devices

Abstract:
This application relates to a wireless charger with reduced heat generation during operation. The wireless charger includes a connector, a charging assembly and a cable connecting the connector and the charging assembly. A converter component has been moved away from the charging assembly, where an electronic device is placed for charging, to the connector. In some embodiments, one or more electromagnetic shielding components protect the components of the wireless charger.

Claims:
What is claimed is: 
     
       1. A wireless charger comprising:
 a connector comprising a plurality of electrical contacts and a DC-to-AC converter disposed within a connector housing, the DC-to-AC converter having an input coupled to at least one of the electrical contacts in the plurality of electrical contacts, and first and second outputs, the DC-to-AC converter configured to convert a DC power signal received at the input to an AC+ signal and an AC− signal on the first and second outputs, respectively; 
 a charger assembly comprising a charger housing that defines an interior cavity and includes a charging surface, a charging coil disposed within the interior cavity in a position spaced apart from the charging surface; 
 a cable coupled between the connector and the charger assembly, the cable comprising a first wire electrically coupled to the first output of the DC-to-AC converter to transmit the AC+ signal to the charging coil and a second wire electrically coupled to the second output of the DC-to-AC converter to transmit the AC− signal to the charging coil; and 
 a faraday cage comprising an EMI shield disposed within the connector housing and encasing the DC-to-AC converter, an electromagnetic shield disposed within the interior cavity of the charger assembly between the charging surface and the charging coil, and a braided conductive shield surrounding the first and second wires of the cable, the faraday cage forming a shielded pathway for the AC+ and AC− signals from the connector to the charger assembly and electrically coupling the connector, the charger, and the cable to a common ground. 
 
     
     
       2. The wireless charger of  claim 1  wherein the faraday cage encloses an entirety of a signal path for the AC+ and AC− signals from the DC-to-AC converter to the charger assembly. 
     
     
       3. The wireless charger of  claim 1  wherein the faraday cage further comprises a ferrite disk disposed within the interior cavity of the charger assembly and being electrically coupled to the common ground. 
     
     
       4. The wireless charger of  claim 3  wherein the faraday cage further comprises a heat sink disposed within the interior cavity of the charger assembly and being electrically coupled to the common ground via the ferrite disk. 
     
     
       5. A wireless charger comprising:
 a connector, a charger assembly, and a cable coupled between the connector and the charger assembly; 
 the connector comprising: a plurality of contacts configured to receive a DC power signal; a DC-to-AC converter disposed within a connector housing and having a converter input and first and second converter outputs, the DC-to-AC converter coupled to receive the DC power signal at the converter input and generate AC+ and AC− signals on the first and second converter outputs, respectively; and an EMI shield disposed within the connector housing and encasing the DC-to-AC converter; 
 the charger assembly comprising: a charger housing that defines an interior cavity and includes a charging surface; a charging coil disposed within the interior cavity in a position spaced apart from the charging surface; an electromagnetic shield disposed within the interior cavity between the charging surface and the charging coil; and a heat sink disposed within the interior cavity; and 
 the cable comprising: first and second wires electrically coupled to the first and second converter outputs, respectively, to transmit the AC+ and AC− signals to the charging coil; one or more tensile fibers extending along a length of the cable; a first insulation layer surrounding the first and second wires and the one or more tensile fibers; a braided conductive shield surrounding the first insulation layer; and an insulative jacket surrounding the braided conductive shield; 
 wherein the EMI shield in the connector, the braided conductive shield in the cable, and the electromagnetic shield in the charger assembly are electrically coupled to a common ground and form a faraday cage having a shielded pathway for the AC+ and AC− signals from the connector to the charger assembly. 
 
     
     
       6. The wireless charger of  claim 5  further comprising:
 third and fourth wires coupled to the first and second converter outputs, respectively, to transmit the AC+ and AC− signals to the charging coil, wherein the first and third wires are positioned on opposing sides of a central tensile fiber and the second and fourth wires are positioned on opposing sides of the central tensile fiber; and 
 a plurality of tensile fibers positioned circumferentially around the central tensile fiber between the first, second, third, and fourth wires and the first insulation layer. 
 
     
     
       7. The wireless charger of  claim 6  wherein each of the first to fourth wires is a wire bundle and each wire bundle comprises:
 a tensile fiber running the length of the wire bundle; 
 a plurality of wire strands circumferentially positioned around the tensile fiber, each wire strand running the length of the wire bundle; and 
 an insulation jacket surrounding the plurality of wire strands. 
 
     
     
       8. The wireless charger of  claim 6  wherein each of the first to fourth wires is a wire bundle and each wire bundle comprises:
 a data line running the length of the wire bundle; 
 a plurality of wires circumferentially positioned around the data line, each of the plurality of wires running the length of the wire bundle; and 
 an insulation jacket surrounding the plurality of wires. 
 
     
     
       9. The wireless charger of  claim 5  wherein the electromagnetic shield of the charger assembly comprises a tail extending from an edge of the electromagnetic shield away from the charging surface, the tail electrically coupled with the braided conductive shield of the cable. 
     
     
       10. The wireless charger of  claim 5  wherein the charger assembly further comprises a ferrite disk disposed between the charging coil and the heat sink, the ferrite disk comprising a channel for receiving the charging coil. 
     
     
       11. The wireless charger of  claim 10  wherein the ferrite disk further comprises a central opening and the charger assembly further comprises an alignment magnet disposed within the central opening. 
     
     
       12. The wireless charger of  claim 10  wherein the ferrite disk is coated with an insulative material that electrically isolates the ferrite disk from the charging coil and the ferrite disk is coupled to the common ground. 
     
     
       13. The wireless charger of  claim 5  wherein the connector is a male plug connector and the connector housing comprises a first opening in which the plurality of contacts are disposed and a second opening through which the cable enters the connector. 
     
     
       14. The wireless charger of  claim 13  wherein the connector further comprises a crimp comprising a circular protrusion that defines the second opening, the crimp electrically coupled to the braided conductive shield. 
     
     
       15. The wireless charger of  claim 5  wherein the connector further comprises a circuit board having the DC-to-AC converter mounted thereon, the circuit board comprising:
 a first plurality of bonding pads coupled to the plurality of contacts; 
 a second plurality of bonding pads coupled to the first and second wires; and 
 electrical traces coupled between the first and second pluralities of bonding pads and the DC-to-AC converter. 
 
     
     
       16. The wireless charger of  claim 5  wherein the charging coil further comprises a flattened end adjacent to an opening of the charger housing. 
     
     
       17. The wireless charger of  claim 5  wherein the heat sink is positioned adjacent to a bottom surface of the charger assembly and serves as ballast. 
     
     
       18. A wireless charging device, the wireless charging device comprising:
 a connector electrically coupleable with a power source, the connector comprising: contacts for electrically coupling with the power source and receiving a direct current (DC) signal from the power source; and a converter attached to the contacts, the converter receiving the DC signal and converting the DC signal to a positive alternating current (AC+) signal and a negative alternating current (AC−) signal; 
 a cable electrically coupled with the connector and comprising a plurality of wires for transmitting the AC+ signal and the AC− signal from the converter, the plurality of wires including at least one wire for transmitting the AC+ signal and at least one wire for transmitting the AC− signal; 
 a charging assembly electrically coupled with the cable for receiving the AC+ and the AC− signals, the charging assembly comprising: a housing that defines an interior cavity and includes a charging surface for receiving an electronic device; a heat sink disposed within the interior cavity, the heat sink including first and second opposing faces with an opening extending from the first face to the second face through the heat sink, the first face adjacent to a bottom surface of the housing; a magnet disposed within the opening of the heat sink; an inductive coil disposed between the second face of the heat sink and the charging surface, the inductive coil electrically coupled with the cable and operable to receive the AC+ and AC− signals and wirelessly transmit power across the charging surface; and an electromagnetic shield disposed between the inductive coil and the charging surface, the electromagnetic shield comprising a tail extending from the electromagnetic shield to the bottom surface of the housing; and 
 a faraday cage comprising an EMI shield disposed within the connector and encasing the converter, the electromagnetic shield in the charging assembly, and a braided conductive shield surrounding the plurality of wires, the faraday cage forming a shielded pathway for the AC+ and AC− signals from the connector to the charging assembly and electrically coupling the connector, the charging assembly, and the cable to a common ground. 
 
     
     
       19. The wireless charging device of  claim 18  wherein the cable further comprises a plurality of tensile fibers and wherein at least one of the tensile fibers is wrapped in a conductive material and the conductive material transmits data between the connector and the charging assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional Application No. 62/882,241, filed on Aug. 2, 2019, and titled “THERMAL MITIGATION FOR WIRELESS CHARGING DEVICES,” the content of which is herein incorporated by reference in its entirety for all purposes. 
    
    
     FIELD 
     The described embodiments relate generally to inductive charging. More particularly, the present embodiments are directed towards inductive chargers with reduced heat generation during operation. 
     BACKGROUND OF THE INVENTION 
     Electronic devices, such as smart phones, tablet computers, laptop computers, smart watches, wearable devices, and the like can be powered by one or more internal batteries. Through use, the batteries can lose charge, requiring periodic recharging. Some electronic devices include circuitry that enables the batteries to be charged by connecting them to a power source via a physical cable. Other electronic devices include circuitry that enables the batteries to be recharged wirelessly, for example, by placing the electronic device on a wireless charger and inductively transferring power from a coil in the wireless charger to a coil in the electronic device. 
     During wireless charging, heat is typically generated. To avoid excessive heat generation and prevent the batteries from overheating, the current to the inductive coil can be decreased or temporarily stopped which can undesirably increase the charging time of the batteries. 
     BRIEF SUMMARY OF THE INVENTION 
     This disclosure describes various embodiments that relate to inductive chargers having improved thermal efficiency. In some embodiments one or more components that generate heat during a wireless charging operation are moved out of the housing of a wireless charger away from the electronic device being charged. For example, in some embodiments the DC-to-AC converter, which can be a source of heat during a charging operation, is disposed in a portion of the wireless charger that is separate and distinct from the housing in which the charging coil is disposed. Moving the DC-to-AC converter out of the housing and away from the electronic device can reduce the amount of heat that is transmitted to an electronic device being charged and thus enables a wireless charging operation to be maintained for longer durations and/or at higher power levels than may otherwise be possible. This in turn can reduce the charging time required to charge the electronic device. Additionally, moving the DC-to-AC converter and other associated electronic circuitry out the housing in which the charging coil is disposed enables the size of the housing to be reduced 
     In some embodiments a wireless charger can include a connector, a wireless charging assembly and a cable extending between the charger and the wireless charging assembly. A DC-to-AC converter for converting a DC power signal to AC+ and AC− signals that can be used to wireless charge an electronic device can be disposed in a housing of the connector and thus be thermally isolated from the wireless charging assembly, which is coupled to the connector only by the cable. The AC+ and AC− signals can be transmitted from the connector to the charging assembly via wires in the cable. The cable can also include protective layers for protecting the wires from electromagnetic interference, heat, and damage. The charging assembly can include its own housing encasing a charging coil, an electromagnetic shield and a heatsink to further improve the thermal efficiency of the charger. The charging coil receives the AC+ and AC− signals and can generate a time-varying electromagnetic field to charge electronic devices placed on the charging assembly. In some examples, the electromagnetic shield can share a common ground with a protective layer in the cable and the electromagnetic surround in the connector, encasing the entire AC signal path from the connector to the charging assembly and reducing EMC radiated emissions. 
     A wireless charger is disclosed and includes the following: a connector comprising a plurality of electrical contacts and a DC-to-AC converter disposed within a connector housing, the DC-to-AC converter having an input coupled to at least one of the electrical contacts in the plurality of electrical contacts, and first and second outputs, the DC-to-AC configured to convert a DC power signal received at the input to AC+ and AC− signals on the first and second outputs, respectively; a charger assembly comprising a charger housing that defines an interior cavity and includes a charging surface, a charging coil disposed within the interior cavity in position spaced apart from the charging surface; and a cable coupled between the connector and the charger assembly, the cable comprising a first wire electrically coupled to the first converter output to transmit the AC+ to the charging coil and a second wire electrically coupled to the second converter output to transmit the AC− signal to the charging coil. 
     Another wireless charger is disclosed and includes the following: a connector, a charger assembly, and a cable coupled between the connector and the charger assembly; the connector comprising: plurality of contacts configured to receive a DC power signal; a DC-to-AC converter disposed within a connector housing and having a converter input and first and second converter outputs, the DC-to-AC converter coupled to receive the DC power signal at the converter input and generate AC+ and AC− signals on the first and second converter outputs, respectively; and an EMI shield disposed within the connector housing and encasing the DC-to-AC converter; the charger assembly comprising: a charger housing that defines an interior cavity and includes a charging surface; a charging coil disposed within the interior cavity in position spaced apart from the charging surface; an electromagnetic shield disposed within the interior cavity between charging surface and the charging coil; and a heatsink disposed within the interior cavity; and the cable comprising: first and second wires electrically coupled to first and second converter outputs, respectively, to transmit the AC+ and AC− signals to the charging coil; one or more tensile fibers extending along a length of the cable; a first insulation layer surrounding the first and second wires and the one or more tensile fibers; a braided conductive shield surrounding the first insulation layer; and an insulative jacket surrounding the braided conductive shield; wherein the EMI shield in the connector, the braided conductive shield in the cable and electromagnetic shield in the charger assembly are all coupled to a common ground. 
     A wireless charging device is disclosed and includes the following: a connector electrically coupleable with a power source, the connector comprising: contacts for electrically coupling with the power source and receiving direct current (DC) from the power source; and a converter attached to the contacts, the converter receiving the DC and converting the DC to positive alternating current (AC+) and negative alternating current (AC−); a cable electrically coupled with the connector and comprising a plurality of wires for transmitting the AC+ and the AC− from the converter, the plurality of wires including at least one wire for transmitting the AC+ and at least one wire for transmitting the AC−; a charging assembly electrically coupled with the cable for receiving the AC, the charging assembly comprising: a housing that defines an interior cavity and includes a charging surface for receiving an electronic device; a heat sink disposed within the interior cavity, the heat sink including first and second opposing faces with an opening extending from the first face to the second face through the heat sink, the first face adjacent to a bottom surface of the housing; a magnet disposed within the opening of the heat sink; an inductive coil disposed between the second face of the heat sink and the charging surface, the inductive coil electrically coupled with the cable and operable to receive the AC and wirelessly transmit power across the charging surface; and an electromagnetic shield disposed between the inductive coil and the charging surface, the electromagnetic shield comprising a tail extending from the electromagnetic shield to the bottom surface of the housing. 
     To better understand the nature and advantages of the present invention, reference should be made to the following description and the accompanying figures. It is to be understood, however, that each of the figures is provided for the purpose of illustration only and is not intended as a definition of the limits of the scope of the present invention. Also, as a general rule, and unless it is evident to the contrary from the description, where elements in different figures use identical reference numbers, the elements are generally either identical or at least similar in function or purpose. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified illustration of a previously known wireless charger; 
         FIG. 2  is a simplified illustration of a wireless charger according to some embodiments of the present invention; 
         FIG. 3  is an illustration of an exploded view of a wireless charger including a connector, a cable, and a charging assembly according to some embodiments of the present invention; 
         FIG. 4  is a simplified illustration of certain sub-components of a connector that can be incorporated into the wireless charger of  FIG. 3  according to some embodiments of the present invention; 
         FIGS. 5 and 6  are simplified cross sections of cables that can be incorporated into the wireless charger of  FIG. 3  according to some embodiments of the present invention; 
         FIGS. 7A and 7B  are simplified illustrations of shielded pathways that can be incorporated into the wireless charger of  FIG. 3  according to some embodiments of the present invention; 
         FIG. 8  is a simplified cross section of a charging assembly that can be incorporated into the wireless charger of  FIG. 3  according to some embodiments of the present invention; 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A wireless charger for an electronic device typically includes a charging coil positioned within a housing adjacent to a charging interface or surface and a variety of electronic components that supply power to the coil. Some of these components, such as a DC-to-AC converter that converts a direct current (DC) received by the wireless charger to a time varying alternating current (AC) that is delivered to the charging coil, can generate heat during the charging process. If the temperature of the wireless charger becomes sufficiently high within the housing near the charging interface or surface, it can raise the temperature of the electronic device being charged, which in turn, can cause the batteries in the electronic device to overheat. To avoid overheating the batteries, some wireless chargers can pulse or temporarily turn off power to the charging coil. However, this can increase the time it takes to charge the electronic device. 
     Some embodiments of the invention provide a solution to this problem by moving one or more components that generate heat out of the housing, away from the electronic device, to a different part of the charger assembly. For example, in some embodiments the DC-to-AC converter is disposed in a portion of the wireless charger that is separate and distinct from the housing in which the charging coil is disposed. Moving the DC-to-AC converter out of the housing and away from the electronic device reduces the amount of heat that is transmitted to an electronic device being charged and thus enables a wireless charging operation to be maintained for longer durations and/or at higher power levels than may otherwise be possible. This in turn can reduce the charging time required to charge the electronic device. Additionally, moving the DC-to-AC converter and other associated electronic circuitry out the housing in which the charging coil is disposed enables the size of the housing to be reduced. 
     These and other embodiments are discussed below with references to  FIGS. 1-7 ; however, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
       FIG. 1  is a simplified illustration of a previously known wireless charging device  100 . The wireless charging device  100  includes a charging coil  102  and electronic circuitry  104  disposed within a housing  106 . Charging coil  102  is disposed adjacent to a charging surface  105  that can be a portion of an exterior surface of housing  106 . Electronic circuitry  104  provides power to the charging coil and includes a DC-to-AC converter that converts a DC current received via a cable  108  from an external source (e.g., a USB connector, not shown, that provides a 5 volt DC current to the wireless charging device  100 ) to an AC current. The AC current can be supplied to charging coil  102 , which generates a time-varying electromagnetic field across the charging surface that can induce a current within an inductive receiver coil in an electronic device positioned on or adjacent to charging surface  105 . The electronic device can then use the induced current, for example, to recharge an internal battery. 
     When electronic circuitry  104  converts the DC current to an AC current, heat is generated that can raise the temperature within housing  106  of the wireless charging device  100 . The increased temperature within the housing  106  of the wireless charging device  100  can cause the batteries in the electronic device to heat up and possibly overheat. To avoid overheating the batteries in the electronic device, electronic circuitry  104  can temporarily decrease or stop supplying AC current to the charging coil  102 . However, decreasing or stopping the AC current flow can increase the time required to charge the electronic device. 
       FIG. 2  is a simplified illustration of a wireless charging device  200  according to some embodiments of the present invention. The wireless charging device  200  includes a connector  210  for receiving and converting power form a power source, a charging assembly  230  for receiving the converted power and using it to wirelessly charge an electronic device and a cable  220  for transmitting the converted power from the connector  210  to the charging assembly  230 . In contrast to wireless charging device  100  shown in  FIG. 1 , wireless charging device  200  does not include a DC-to-AC converter within the housing of charging assembly  230 . Instead, the electronic circuitry  204  that converts a DC current to the AC current necessary to wirelessly charge an electronic device is disposed within a housing of connector  210 . Since connector  210  is separated from charging assembly  230  and the two components are only coupled to each other by cable  220 , heat generated by the DC-to-AC converter and its associated circuitry is not transmitted (or only minimally transmitted) to the charging assembly reducing heat local to the wireless charging assembly  230  and optimizing the thermal efficiency of wireless charging device  200  during wireless charging. Additionally, in some embodiments, the connector  210 , the cable  220 , and the charging assembly  230  are electrically coupled to share a common ground that encases the entire AC signal path from connector  210  to charging assembly  230 , reducing EMC radiated emissions as discussed in detail below. 
     The connector  210  can be electrically coupled with a power source to receive electric current. In some embodiments, connector  210  can be a male plug connector that can be inserted into a corresponding female connector in an AC-to-DC adapter, such as an adapter that can be plugged into a standard AC wall outlet. For example, in some embodiments, connector  210  can be a type A or a type C Universal Serial Bus (USB) connector. The connector  210  can include a housing  211  that encases and protects various internal components of the connector  210 . The connector  210  can receive a DC current from a power source via one or more electrical contacts  212 . The contacts  212  can transmit the electric current from the power source to electronic circuitry  204  disposed within housing  211 . Electronic circuitry  204  can include, among other components, a DC-to-AC converter that can receive a DC current from the power source and convert the DC current to an AC current that can be supplied to charging assembly  230  via cable  220 . The contacts  212  can be arranged according to a standardized pinout (e.g., USB-A, USB-B, USB-C, etc.) that matches the pinout of the contacts in the power source. In some embodiments, the contacts  212  can include one or more contacts for receiving and/or transmitting data in addition to receiving power. 
     The DC-to-AC converter within electronic circuitry  204  can receive the DC electric current from the power source via the contacts  212  and convert it to an AC+ current and an AC− current. The DC-to-AC converter can be a variety of appropriate chips or circuitry that converts a DC signal to an AC signal. In various embodiments, and as non-limiting examples, the converter can be part of an ASIC, can be within a microcontroller or other microprocessor chip or can be made from various discrete components. In some embodiments, the electronic circuitry  204  can include a Main Logic Board (MLB) and/or a Printed Circuit Board Assembly (PCBA) that has a first set of bonding pads that can be electrically coupled to the contacts  212  and a second set of bonding pads that can be coupled to wires within cable  220 . The DC-to-AC converter can be mounted to the MLB and electrical traces on the MLB can couple an input of the DC-to-AC converter to a bonding pad in the first set of bonding pads that is coupled to one of the contacts  212  that receives the DC current and can couple outputs of the converter to bonding pads in the second set of bonding pads on the MLB. 
     In some embodiments, the connector  210  can include a shield (not shown in  FIG. 2 ) within housing  211  that encases the electronic circuitry  204  including the DC-to-AC converter. The shield can reduce or prevent EMI from reaching electronic circuitry  204 . The shield can be grounded to a common ground for wireless charging device  200 . As described further below, the shield can be connected with EMI shielding components in cable  220  and charging assembly  230  to form an EMI shield that encases the entire AC signal path and reduces or prevents AC signal loss. 
     The connector  210  can be electrically coupled with the cable  220  to transmit the AC signal from the connector. The cable  220  can include wires for transmitting the AC signal and/or data from the connector  210  to the charging assembly  230 . The wires can be surrounded by a shield layer to reduce or prevent EMI from reaching the wires, and a protective layer providing protection against heat and damage. The shield layer can be connected with the common ground via an electrical connection with the shield. For ease of illustration the wires, shield layer and protective layer are not shown in  FIG. 2  and are instead shown and discussed in more detail in conjunction with  FIG. 5  below. 
     The cable  220  can be electrically coupled with the charging assembly  230  to transmit the AC signal to the charging assembly. In some embodiments, the charging assembly  230  is a circular puck shaped charger but the invention is not limited to any particular shape of charging assembly  230 . The charging assembly  230  can have a housing  232  that encases the components of the charging assembly  230 . The housing  232  can be made from metal, metal alloy, ceramic, plastic, composite, polycarbonate material, or any other suitable material. A charging surface  233  on the exterior of the housing  232  can receive an electronic device for charging. A charging coil  234  can be positioned inside the housing  232  at a location adjacent to the charging surface. The charging coil can be electrically coupled to the wires within cable  220 , such that when an AC current is supplied to the charging coil  234  a time-varying electromagnetic field is generated across the charging surface. During a charging event, the time-varying electromagnetic field can induce a current within an inductive receiver coil in the electronic device being charged. The charging coil  234  can contain any suitable electrically conductive material (e.g., metals, alloys, semiconductors, conductive ceramics, conductive polymers). 
     An electromagnetic shield  236  can be positioned between the charging coil  234  and the charging surface  233 . The electromagnetic shield  236  can be a capacitive shield that helps to remove coupled noise between the wireless charging device  200  and the electronic device during a charging operation. Electromagnetic shield  236  can drown out some or all of the capacitive coupling that can occur between the charging coil  234  and the receiver coil in the electronic device. In some embodiments, the electromagnetic shield  236  can include a tail for connecting with the common ground for wireless charging device  200  as described below. The electromagnetic shield  236  can connect to the common ground via shield layer  224 . In some embodiments, the electromagnetic shield  236  can be made of multiple thin layers, such as an electrically conductive layer, a dielectric layer and an adhesive layer there between. 
     A heat sink  238  can be included in the charger assembly to reduce the amount of heat emitted to the electronic device. The heat sink  238  can made entirely of or predominantly from a material having a high thermal conductivity (e.g., a metal) to draw the heat away from the electronic device. In some embodiments, the heat sink  238  can be positioned at or near a bottom surface of charging assembly  230  to act as a ballast that provides stability to the charging assembly anchoring it to a surface, such as a table or desk. Additionally or alternatively, the heat sink  238  can be coupled to the common ground of wireless charging device  200  and can provide EMI shielding as discussed herein. 
       FIG. 3  is an illustration of an exploded view of a wireless charger  300  including a connector  310 , a cable  320 , and a charging assembly  330  according to some embodiments of the present invention. Wireless charger  300  and its associated components can be representative of wireless charger  200  shown in  FIG. 2 . 
     The connector  310  can be a male connector that can be mated with a corresponding female connector of a power source or appropriate power adapter. In some embodiments, the connector  310  can correspond to a Universal Serial Bus (USB) connector, such as a Type A or a Type C USB connector. The connector  310  can include contacts  312  aligned to be electrically coupled with a power source when connector  310  is mated with an appropriate receptacle connector. The contacts  312  can be supported and held in place by contact tray  313 . Contact tray  313  can be surrounded by contact housing  309  that defines an exterior shape of the portion of connector  310  that can be inserted into a corresponding female connector. As shown, the contacts  312  are in a four contact configuration, however, embodiments of the invention are not limited to a connector having four contacts and other embodiments can have few or more than four contacts. 
     The four contact configuration can include a contact for power, a contact for ground, and two contacts for data (e.g., for USB+ and USB− signals). The contacts  312  can receive electrical current from the power source and transmit it to electrical circuitry  314 . The electrical circuitry  314  can include a DC-to-AC converter that converts a received DC current to an AC current that can be output as, for example, an AC+ current and an AC− current. The contacts  312  and electrical circuitry  314  can be electrically coupled to each other via one or more traces on an MLB or similar circuit board to which the circuitry is mounted. The contacts can be soldered to bonding pads on the MLB. 
     An electromagnetic shield  318  having an upper and lower portions  318   a ,  318   b  encases the electrical circuitry  314 . The electromagnetic shield  318  can reduce or prevent electromagnetic interference from reaching the electrical circuitry including the DC-to-AC converter. The electromagnetic shield  318  can correspond to or comprise conductive or magnetic materials. In some embodiments, the electromagnetic shield  318  and contact housing  309  can be connected to a common ground for wireless charger  300 . The electromagnetic shield  318  and contact housing  309  can be coupled together as part of a connector housing and can be included in a shielded pathway (i.e., a faraday cage) for the AC signal, reducing or preventing signal loss from EMI as described below. 
     A wire crimp  323  can hold wire bundles  322  in place. The wire crimp  323  can include a circular opening for receiving the wire bundles  322  that can then be deformed to hold the wire bundles  322  in place. In some embodiments, the wire crimp  323  can be connected to the common ground for the wireless charger  300  and included in the shielded pathway. 
     An outer shell or boot  315  can surround the electromagnetic shield  318  and wire crimp  323 , providing additional structural support for the connector  310  as well as a pleasant cosmetic appearance. The outer boot  315  can have an open end for receiving a portion of the connector housing and a portion of the contact housing  309  can extend beyond the outer boot enabling the connector housing to be inserted into a corresponding female connector. Outer boot  315  can be fabricated from a plastic or polymer material and can be molded over the electrically conductive connector housing. 
     The cable  320  can be electrically coupled with the electrical circuitry  314  to transmit the electric current(s) (e.g., AC+ and AC− currents) from the connector  310  to the charging assembly  330 . The cable  320  can include wire bundles  322  for transmitting the electric current surrounded by one or more protective layers  324  providing protection against electromagnetic interference, heat, and damage. One of the protective layers  324  can be connected to the common ground and shield the electric current(s) transmitted through wire bundles  322  from EMI as part of the shielded pathway as described below in conjunction with  FIG. 5 . 
     The charging assembly  330  can include a housing base  331  and a housing cap  332  forming a housing encasing the internal components of the charging assembly  330 . The housing cap  332  includes a charging surface  333  for receiving an electronic device. A charging coil  334  can be positioned within the housing directly below the charging surface  333 . Charging coil  3334  can be coupled to wire bundle  322  to receive an electric current(s) (e.g., AC+ and AC− currents) from the cable  320  to generate a time-varying electromagnetic field across the charging surface as described above. Housing cap  332  can be made from a material that allows the electromagnetic field generated by the charging coil to pass through charging surface  333 . In some embodiments, the charging coil  334  can be optimized to include the greatest number of coils in an available space in the housing. 
     An electromagnetic shield  336  can be positioned between the housing cap  332  and a charging coil  334 . The electromagnetic shield  336  can shield components in charging assembly  330  during a charging operation. The electromagnetic shield  336  can correspond to or comprise a suitable thin, flexible, material. In some embodiments, the electromagnetic shield  336  can comprise one or more layers including, for example, a dielectric layer, an adhesive layer, and a conductive layer. The electromagnetic shield  336  can include a tail that extends towards a bottom surface of the housing base  331 . In some embodiments the tail of the electromagnetic shield  336  can connect the electromagnetic shield  336  to the common ground. 
     The charging assembly  330  can include a ferromagnetic sleeve  338  positioned such that the charging coil  334  is located between the ferromagnetic sleeve  338  and the charging surface  333 . The ferromagnetic sleeve  338  can direct the electromagnetic flux lines from the charging coil  334  to the electronic device. The ferromagnetic sleeve  338  can include ferrite material (ceramic material composed of iron oxide) or any other suitable ferromagnetic material. The ferromagnetic sleeve  338  can correspond to a ferrite disk. In some embodiments, the ferromagnetic sleeve  338  can include areas where insulation has been applied. The insulation can prevent the ferromagnetic sleeve  338  from contacting and shorting the charging coil  334 . The insulation can correspond to or comprise epoxy coating. The ferromagnetic sleeve  338  can include an opening  339  for receiving a magnet  340 . The magnet  340  can aid in aligning the electronic device on the charging surface  333 . The magnet  340  can extend from the housing base  331  through openings in the components of the charging assembly  330 , with the top of the magnet  340  being adjacent to the charging surface  333 . 
     A heat sink  344  can pull heat, generated by components in the charging assembly  330 , away from the electronic device when it is on the charging surface  333 . Additionally or alternatively, the heat sink  344  can be used as a ballast in the charging assembly  330  to add weight to the charging assembly  330  and prevent the charging assembly from being easily moved when the electronic device is set on the charging surface  333 . In some embodiments, the heat sink  344  can be connected to the common ground via the ferromagnetic sleeve  338  and part of the shielded pathway. 
       FIG. 4  is a simplified illustration of certain sub-components of a connector  400  that can be incorporated into the wireless charger  300  of  FIG. 3  according to some embodiments of the present invention. For example, connector  400  can be representative of some embodiments of connector  310 . The connector  400  includes contacts  410  aligned to be electrically coupled with a power source when connector  400  is mated with an appropriate connector (e.g., a receptacle connector) associated with the power source. The contacts can be supported and held in place by contact support tray  402 . 
     A circuit board  420  (shown in  FIG. 4  in duplicate with both its upper and lower surfaces exposed) can be electrically coupled with the contacts via bonding pads  422 . The circuit board  420  can include one or more traces extending between bonding pads  422  and electrical circuitry (not shown). The circuit board  420  can correspond to a PCBA or MLB. 
     In some embodiments, contacts  410  include one or more dummy contacts  412  that are not electrically connected to any particular signal or power source and are instead used to strengthen the connection between the contacts  410  and the circuit board  420 . The dummy contacts  412  can correspond to dummy pads  424  on the circuit board  420 . The dummy contacts  412  and the dummy pads  424  can be connected with solder and/or glue. an MLB or other circuit board to which the electrical circuitry is mounted to provide additional structural rigidity and support in the connection between circuit board  420  and the contacts within contact tray  402 . 
       FIG. 5  is a simplified cross section of a cable  500  that can be incorporated into the wireless charger  300  of  FIG. 3  according to some embodiments of the present invention and can be representative of cable  320  shown in  FIG. 3 . The cable  500  can include one or more wire bundles  510  for transmitting an AC current along the length of the cable  500 . The AC current can be split into an AC+ and an AC− current and transmitted through multiple wire bundles  510  to reduce the interference between the currents, for example a wire  510   a  can transmit the AC− signal and wire  510   b  can transmit an AC+ signal. The wire bundles  510  can be optimized to transmit the AC current at a specific frequency with minimal losses. 
     A strengthening member  520  can be included in the cable  500  to increase resistance against stresses put on the cable. The strengthening member  520  can include one or more fibers (e.g., carbon fibers) for strengthening the cable  500  against stresses in a specific direction. For example, the fibers can be used to strengthen the cable  500  against tensile stresses put on the cable. 
     One or more protective layers  530  can surround the wires. The one or more protective layers  530  can provide protection against electromagnetic interference, heat, and damage. The protective layers  530  can include, for example, an insulating jacket and/or a conductive shield. In some embodiments, one or more of the protective layers  530  can be an electrically conductive layer that is electrically coupled between an EMF shield in a connector and an EMF shield in a charging assembly. 
       FIG. 6  is a simplified cross section of a cable  600  that can be incorporated into the wireless charger  300  of  FIG. 3  according to some embodiments of the present invention and can be representative of cable  320  shown in  FIG. 3 . The AC− current can be transmitted through two wires  610   a  spaced apart from each other within the cable  600  and the AC+ current can be transmitted through two wires  610   b  within cable  600 . The wire bundles  610  can be arranged in the cable to reduce interference between wire bundles by separating cables transmitting the same type of AC current. Multiple strengthening members  620  can be included in the cable  600 , increasing resistance against stresses put on the cable. For example, strengthening member  620  can be at the center of the cable  600  encircled by additional four strengthening members, one between outer surfaces of each adjacent wire  610   a ,  610   b  pairing. 
     Each of the wires  610   a ,  610   b  can be a stranded wire that includes multiple strands  612  for transmitting the AC signal surrounding and a central fiber  614  for strengthening the wires. An electrically insulative sheath  616  can surround the wire strands of each wire  610   a ,  610   b . The diameter of each wire strand  612  can be optimized to transmit the electric current at a specific frequency. For example, the diameter of each wire strand  612  can be optimized to transmit the electric current at a frequency of about 380 hertz. The wire strands can be made from copper, copper alloy, or other electrically conductive material. The central fiber  614  can provide resistance against stresses applied to the wires  610   a ,  610   b . In some embodiments, the central fiber  614  can contain conductive material. The conductive material can transmit data along the length of the cable. As described further below, the conductive material can be used as a ground path for another component of the wireless charger  300 . The conductive material can be a conductive foil surrounding the central fiber  614 . 
     Cable  600  can include a multi-layer protective structure  630  that can include, for example, an inner insulating layer  632 , a conductive shield layer  634 , and an outer sheath layer  636 . The inner insulating layer  632  can be made from an electrically insulative material and provide additional structure to cable  600  while also providing thermal and electrical insulation for the wires  610   a ,  610   b . The conductive shield layer  634  can be connected to the common ground and reduce or prevent electromagnetic interference as part of the shielded pathway. The conductive shield layer  634  can protect the AC signal from signal losses caused by electromagnetic interference. In some embodiments, the conductive shield layer  634  is a braided conductive shield. The outer sheath layer  636  can be a polymer layer that provides protection from physical objects in the surrounding environment and provides additional strength. 
       FIGS. 7A and 7B  are simplified illustrations of shielded pathways that can be incorporated into the wireless charger  300  of  FIG. 3  according to some embodiments of the present invention. Each of  FIGS. 7A and 7B  depict a connector and a wireless charging assembly coupled to each other by a cable. As shown in the two figures, in some embodiments of the invention the shielded pathway  700  can extend all the way from the connector housing to the wireless charging assembly including along the entirety of the cable that couples the connector to the wireless charging assembly. For example, the shielded pathway  700  can extend from a contact housing  710  and electromagnetic shield  720  through a conductive shield layer  730  that extends along an entire length of and surrounds one or more wires that carry the AC+ and AC− signals within the cable. The contact housing  710 , electromagnetic shield  720 , and conductive shield layer  730  can be electrically coupled to each other and connected to a common ground of the wireless charger  300 . Shielded pathway  700  can prevent or reduce electromagnetic radiation from interfering with the AC signal. For example, shielded pathway  700  can act as a faraday cage surrounding the entirety of the AC signal path of the wireless charger to prevent or reduce interference from environmental electromagnetic interference. An electromagnetic shield  740  in the charging assembly  330  can be separately connected to the common ground via a separate grounding cable  742 . The electromagnetic shield  740  can be a capacitive shield that helps to remove coupled noise between the wireless charging device  200  and the electronic device during a charging operation. 
     In other embodiments, such as shown in  FIG. 7B , the electromagnetic shield  740  can be electrically connected with the common ground via conductive shield layer  730  in the cable. The electromagnetic shield  740  can be included in the shielded pathway  700 . The AC signal path can be surrounded by the shielded pathway  700  from the contact housing  710  to the electromagnetic shield  740 . 
       FIG. 8  is a simplified cross section of a charging assembly  800  according to some embodiments of the present invention that can be representative of charging assembly  330  shown in  FIG. 3 . The charging assembly  800  can include a housing that includes a bottom housing portion  810  coupled to a cap  812 , which together define an interior cavity of the charging assembly. In some embodiments the bottom housing portion  810  and cap  812  are made from different materials. For example, in some embodiments housing portion  810  can be made from a metal while cap  812  can be made from a plastic or similar material that allows an electromagnetic field to pass through a charging surface  814  of the cap. A charging coil  820 , an EMF shield  830 , a ferromagnetic sleeve  840 , a magnet  850 , and a heat sink  860  can all be disposed within the interior cavity defined by housing portion  810  and cap  812 . 
     As shown in  FIG. 8 , the EMF shield  830  can include a tail  832  extending from the EMF shield to a ground termination point  822 . The ground termination point  822  can serve as an electrical connection point for the shield path described above. An adhesive layer  862  can be included between the ferromagnetic sleeve  840  and the heat sink  860 . In some embodiments, the adhesive layer  862  can form an electrical connection between the ferromagnetic sleeve  840  and the heat sink  860  such that, the ferromagnetic sleeve  840  and the heat sink  860  are electrically connected to the ground termination point  822 . The heat sink  860  can be connected to the common ground, reducing EMC radiated emissions as discussed above. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. 
     It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users.

Metadata:
Filing Date: 20190828
Publication Date: 20211026
Grant Date: 20211026
Priority Date: 20190802
Inventors: HAUG, Grant S.
GRAHAM, Christopher S.
Oro, Aaron A.
JOL, ERIC S.
LARSSON, KARL RUBEN F.
RASMUSSEN, Timothy J.
THOMPSON, PAUL J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01F27/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/00309", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/363", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01F27/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 74260580