PATENT DOCUMENT

Publication Number: US-11476707-B2
Application Number: US-202017108923-A
Country: US
Kind Code: B2

Title: Wireless power system housing

Abstract:
A wireless power system has a wireless power transmitting device such as a charging puck and a wireless power receiving device such as a battery-operated device. The charging puck may be connected to a plug via a cable. The plug may include a boot and a connector. The boot may house a printed circuit board that is positioned closer to one of the boot housing walls.

Claims:
What is claimed is: 
     
       1. A wireless power transmitting device, comprising:
 a device housing; 
 at least one wireless power transmitting coil within the device housing; 
 a cable having a first end connected to the device housing and having a second end; and 
 a plug connected to the second end of the cable, wherein the plug comprises:
 a boot with a boot housing having an upper wall and a lower wall; 
 a connector extending from the boot; 
 a printed circuit board disposed within the boot housing, wherein the printed circuit board is positioned a first distance from the upper wall and a second distance, different than the first distance, from the lower wall; 
 an active electronic component disposed on an upper surface of the printed circuit board facing the upper wall; 
 a passive electronic component disposed on the upper surface of the printed circuit board facing the upper wall; and 
 an underfill barrier structure disposed on the upper surface between the active electronic component and the passive electronic component, wherein underfill material is disposed under the active electronic component and wherein the passive electronic component is free of underfill material. 
 
 
     
     
       2. The wireless power transmitting device of  claim 1 , wherein the second distance is greater than the first distance, wherein the active electronic component has a first height, and wherein the plug comprises an additional passive electronic component having a second height, greater than the first height, mounted on a lower surface of the printed circuit board facing the lower wall. 
     
     
       3. The wireless power transmitting device of  claim 1 , wherein:
 the device housing houses an inverter configured to drive the at least one wireless power transmitting coil and houses a device microcontroller; and 
 the boot housing houses a converter and a boot microcontroller that communicates with the device microcontroller. 
 
     
     
       4. The wireless power transmitting device of  claim 3 , wherein:
 the second distance is greater than the first distance; and 
 the converter comprises an inductor mounted on a lower surface of the printed circuit board facing the lower wall. 
 
     
     
       5. The wireless power transmitting device of  claim 1 , wherein the plug comprises:
 a plurality of passive electronic components mounted on a lower surface of the printed circuit board facing the lower wall. 
 
     
     
       6. The wireless power transmitting device of  claim 5 , wherein the active electronic component has a first height, and wherein the plurality of passive electronic components have second heights greater than the first height. 
     
     
       7. The wireless power transmitting device of  claim 6 , wherein the second distance is greater than the first distance. 
     
     
       8. The wireless power transmitting device of  claim 5 , wherein a region between the plurality of passive electronic components and the lower surface of the printed circuit board is devoid of underfill material. 
     
     
       9. The wireless power transmitting device of  claim 1 , wherein the plug comprises:
 only passive electronic components disposed on a lower surface of the printed circuit board facing the lower wall. 
 
     
     
       10. A wireless power transmitting device, comprising:
 a device housing; 
 at least one wireless power transmitting coil within the device housing; 
 a cable having a first end connected to the device housing and having a second end; and 
 a plug connected to the second end of the cable, wherein the plug comprises:
 a boot with a boot housing; 
 a connector extending from the boot; 
 a printed circuit board disposed within the boot housing; 
 only active components having first heights disposed on a first outer surface of the printed circuit board; 
 passive components having second heights, greater than the first height, disposed on a second outer surface of the printed circuit board opposing the first outer surface; and 
 an underfill barrier structure separating the second outer surface of the printed circuit board into a first region in which the passive components are disposed and a second region, wherein the first region is free of underfill material and wherein the second region includes underfill material. 
 
 
     
     
       11. The wireless power transmitting device of  claim 10 , wherein the second heights are at least 50% greater than the first heights. 
     
     
       12. The wireless power transmitting device of  claim 10 , wherein:
 the active components comprise a boot microcontroller; and 
 the passive components comprise an inductor and a capacitor. 
 
     
     
       13. The wireless power transmitting device of  claim 10 , wherein:
 the boot housing has an upper wall and a lower wall; and 
 the printed circuit board is positioned a first distance from the upper wall and a second distance, different than the first distance, from the lower wall. 
 
     
     
       14. The wireless power transmitting device of  claim 13 , wherein the second distance is greater than the first distance. 
     
     
       15. The wireless power transmitting device of  claim 14 , wherein the second distance is at least 20% greater than the first distance. 
     
     
       16. An apparatus comprising:
 a housing having a first end, a second end opposing the first end, a first wall, and a second wall opposing the first wall; 
 a connector extending from the first end of the housing; 
 a cable extending from the second end of the housing; 
 a circuit board disposed within the housing and positioned a first distance from the first wall and a second distance, greater than the first distance, from the second wall; 
 first electronic components disposed on a first surface of the circuit board facing the first wall; and 
 underfill material disposed under the first electronic components; 
 second electronic components disposed on a second surface of the circuit board facing the second wall, the second electronic components being free of underfill material; and 
 an underfill barrier structure at least partially surrounding the second electronic components on the second surface of the circuit board. 
 
     
     
       17. The apparatus of  claim 16 , wherein the first electronic components comprise active components having first heights and wherein the second electronic components comprise passive components having second heights, greater than the first heights.

Description:
This application claims the benefit of provisional patent application No. 63/088,234, filed Oct. 6, 2020, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to power systems, and, more particularly, to wireless power systems for charging electronic devices. 
     BACKGROUND 
     In a wireless charging system, a wireless power transmitting device such as a charging mat or charging puck wirelessly transmits power to a wireless power receiving device such as a portable electronic device. The portable electronic device has a coil and rectifier circuitry. The coil of the portable electronic device receives alternating-current wireless power signals from the wireless power transmitting device. The rectifier circuitry converts the received signals into direct-current power. 
     SUMMARY 
     A wireless power system has a wireless power transmitting device and a wireless power receiving device. The wireless power receiving device may be a wristwatch having a magnetic core with at least first and second wireless power receiving coils. The wireless power transmitting device may be a charging puck connected to a plug such as a Universal Serial Bus plug via a cable. 
     In some embodiments, a wireless power transmitting device is provided that includes a device housing, at least one wireless power transmitting coil within the device housing, a cable having a first end connected to the device housing and having a second end, and a plug connected to the second end of the cable. The plug includes a boot with a boot housing having an upper wall and a lower wall, a connector extending from the boot, and a printed circuit board disposed within the boot housing, where the printed circuit board is positioned a first distance from the upper wall and a second distance, different than the first distance, from the lower wall. Taller passive components can be mounted on the side of the printed circuit board with more available spacing to the boot wall. Shorter active components can be mounted on the opposing side of the printed circuit board with less spacing to the boot wall. Underfill material may be disposed under the active components. The passive components can be free of any underfill material. 
     In some embodiments, a wireless power transmitting device is provided that includes a device housing, at least one wireless power transmitting coil within the device housing, a cable having a first end connected to the device housing and having a second end, and a plug connected to the second end of the cable. The plug includes a boot with a boot housing, a connector extending from the boot, a printed circuit board disposed within the boot housing, first electronic components arranged in a first area on the printed circuit board, second electronic components arranged in a second area on the printed circuit board, underfill material disposed under the first electronic components in the first area, and an underfill barrier configured to block the underfill material from reaching the second electronic components in the second area. The second electronic components can be low acoustic noise capacitors (sometimes referred to as reduced noise acoustic capacitors) that are coupled to a power rail of an inverter driving that wireless power transmitting coil. The underfill barrier may be a metal barrier structure. 
     In some embodiments, a wireless power transmitting device is provided that includes a device housing, at least one wireless power transmitting coil within the device housing, a plug, and a cable having a first end connected to the device housing and having a second end connected to the plug. The cable includes a differential signal path, a first single-ended signal line capacitively coupled to the differential signal path by a first amount, and a second single-ended signal line capacitively coupled to the differential signal path by a second amount equal to the first amount to reduce crosstalk between the first and second single-ended signal lines. The differential signal path includes a positive signal line coupled to the first single-ended signal line by the first amount and coupled to the second single-ended signal line by the second amount and includes a negative signal line coupled to the first single-ended signal line by the first amount and coupled to the second single-ended signal line by the second amount. 
     In some embodiments, a wireless power transmitting device is provided that includes a device housing that houses a wireless power transmitting coil, device control circuitry, and a temperature sensor configured to output a temperature value, a cable having a first end connected to the housing and having a second end, and a plug connected to the second end of the cable and having boot control circuitry, where the device control circuitry is configured to transmit heartbeat signals to the boot control circuitry via the cable and where the device control circuitry is configured to stop transmission of the heartbeat signals in response to detecting that the temperature value has exceeded a predetermined threshold. The boot control circuitry can stop providing power to the wireless power transmitting coil via the cable in response to detecting that the device control circuitry has stopped transmitting the heartbeat signals by latching off an electronic fuse within the boot housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative wireless charging system that includes a wireless power transmitting device and a wireless power receiving device in accordance with some embodiments. 
         FIG. 2  is a circuit diagram of wireless power transmitting and receiving circuitry in accordance with some embodiments. 
         FIG. 3  is a side view of an illustrative wireless power transmitting device such as a wireless charging puck connected to a connector plug via a cable in accordance with some embodiments. 
         FIG. 4A  is a cross-sectional side view of a plug showing a printed circuit board that is closer to the upper boot wall in accordance with some embodiments. 
         FIG. 4B  is a cross-sectional side view of a plug showing a printed circuit board that is closer to the lower boot wall in accordance with some embodiments. 
         FIG. 4C  is a cross-sectional side view showing how underfill material may be disposed under the thinner components but not under the taller components within a boot in accordance with some embodiments. 
         FIG. 5A  is a top (layout) plan view of a printed circuit board having an underfill barrier configured to prevent underfill material from reaching low acoustic noise capacitors in accordance with some embodiments. 
         FIG. 5B  is a top plan view showing a printed circuit board having an underfill barrier surrounding a region closer to the center of the printed circuit board in accordance with some embodiments. 
         FIG. 5C  is a top plan view showing a printed circuit board having multiple underfill barriers surrounding different regions on the printed circuit board in accordance with some embodiments. 
         FIGS. 6A-6D  are cross-sectional views of a cable with a differential data path interposed between two single-ended signal paths to mitigate crosstalk in accordance with some embodiments. 
         FIG. 7A  is a diagram showing how heartbeat signals can be transmitted between a power transmitting device and a plug in accordance with some embodiments. 
         FIG. 7B  is a flow chart of illustrative steps for using a plug to send heartbeat signals to a power transmitting device in accordance with some embodiments. 
         FIG. 7C  is a flow chart of illustrative steps for using a power transmitting device to send heartbeat signals to a plug in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     A wireless power system includes a wireless power transmitting device such as a wireless charging puck. The wireless power transmitting device wirelessly transmits power to a wireless power receiving device such as a cellular telephone, wristwatch, or other electronic equipment. The wireless power receiving device uses power from the wireless power transmitting device for powering the device and for charging an internal battery. 
     An illustrative wireless power system (wireless charging system) is shown in  FIG. 1 . As shown in  FIG. 1 , wireless power system  8  includes a wireless power transmitting device such as wireless power transmitting device  12  and includes a wireless power receiving device such as wireless power receiving device  24 . Wireless power transmitting device  12  includes control circuitry  16 . Wireless power receiving device  24  includes control circuitry  30 . Control circuitry in system  8  such as control circuitry  16  and control circuitry  30  is used in controlling the operation of system  8 . This control circuitry may include processing circuitry associated with microprocessors, power management units, baseband processors, digital signal processors, microcontrollers, and/or application-specific integrated circuits with processing circuits. The processing circuitry implements desired control and communications features in devices  12  and  24 . For example, the processing circuitry may be used in selecting coils (in embodiments with multiple coils), determining power transmission levels, processing sensor data and other data, processing user input, handling negotiations between devices  12  and  24 , sending and receiving in-band and out-of-band data, making measurements, and otherwise controlling the operation of system  8 . 
     Control circuitry in system  8  may be configured to perform operations in system  8  using hardware (e.g., dedicated hardware or circuitry), firmware and/or software. Software code for performing operations in system  8  is stored on non-transitory computer readable storage media (e.g., tangible computer readable storage media) in control circuitry  8 . The software code may sometimes be referred to as software, data, program instructions, instructions, or code. The non-transitory computer readable storage media may include non-volatile memory such as non-volatile random-access memory (NVRAM), one or more hard drives (e.g., magnetic drives or solid state drives), one or more removable flash drives or other removable media, or the like. Software stored on the non-transitory computer readable storage media may be executed on the processing circuitry of control circuitry  16  and/or  30 . The processing circuitry may include application-specific integrated circuits with processing circuitry, one or more microprocessors, a central processing unit (CPU) or other processing circuitry. 
     Power transmitting device  12  may be a stand-alone power adapter (e.g., a wireless power transmitting device that includes power adapter circuitry), may be a wireless charging puck or other device that is coupled to a power adapter or other equipment by a cable, may be a portable device, may be equipment that has been incorporated into furniture, a vehicle, or other system, may be a removable battery case, or may be other wireless power transfer equipment. Illustrative configurations in which wireless power transmitting device  12  is a wireless charging puck having a cable with a plug that is adapted to mate with a device such as a power adapter or other electronic equipment with a USB connector port are sometimes described herein as an example. 
     Power receiving device  24  may be a portable electronic device such as a cellular telephone, wristwatch, or other electronic equipment. Power transmitting device  12  may be coupled to a wall outlet (e.g., an alternating current power source) and may use AC-DC converter to produce direct-current (DC) power and/or may have a battery for supplying power. In some embodiments, which are described herein as an example, AC-DC converter  14  is a stand-alone power converter or is incorporated into a laptop computer or other device with a connector port (e.g., a USB connector port). With this type of arrangement, device  12  is separate from the equipment that includes converter  14  and has a cable that plugs into the connector port to receive DC power from converter  14 . 
     The DC power may be used to power control circuitry  16 . During operation, a controller in control circuitry  16  uses power transmitting circuitry  52  to transmit wireless power to power receiving circuitry  54  of device  24 . Power transmitting circuitry  52  may have switching circuitry (e.g., inverter circuitry  61  formed from switches such as transistors) that is turned on and off based on control signals provided by control circuitry  16  to create AC current signals through one or more wireless power transmitting coils such as wireless power transmitting coils  36 . As an example, coils  36  may be arranged in a planar coil array (e.g., in configurations in which device  12  is a wireless charging mat) or may be arranged to form a cluster of coils (e.g., in configurations in which device  12  is a wireless charging puck). As another example, device  12  may have only a single coil. As another example, device  12  may have multiple coils (e.g., two or more coils, four or more coils, six or more coils, 2-6 coils, fewer than 10 coils, etc.). 
     As the AC currents pass through one or more coils  36 , the coils  36  produce electromagnetic field signals  44  in response to the AC current signals. Electromagnetic field signals (sometimes referred to as wireless power signals)  44  can then induce a corresponding AC current to flow in one or more nearby receiver coils such as coil  48  in power receiving device  24 . When the alternating-current electromagnetic fields are received by coil  48 , corresponding alternating-current currents are induced in coil  48 . Rectifier circuitry such as rectifier circuitry  50 , which contains rectifying components such as synchronous rectification metal-oxide-semiconductor transistors arranged in a bridge network, converts received AC signals (received alternating-current signals associated with electromagnetic field signals  44 ) from one or more coils  48  into DC voltage signals for powering device  24 . 
     The DC voltage produced by rectifier circuitry  50  (sometime referred to as rectifier output voltage Vrect) can be used in charging a battery such as battery  58  and can be used in powering other components in device  24 . For example, device  24  may include input-output devices  56  such as a display, touch sensor, communications circuits, audio components, sensors, light-emitting diode status indicators, other light-emitting and light detecting components, and other components and these components (which form a load for device  24 ) may be powered by the DC voltages produced by rectifier circuitry  50  (and/or DC voltages produced by battery  58 ). 
     Device  12  and/or device  24  may communicate wirelessly using in-band or out-of-band communications. Device  12  may, for example, have wireless transceiver circuitry  40  that wirelessly transmits out-of-band signals to device  24  using an antenna. Wireless transceiver circuitry  40  may be used to wirelessly receive out-of-band signals from device  24  using the antenna. Device  24  may have wireless transceiver circuitry  46  that transmits out-of-band signals to device  12 . Receiver circuitry in wireless transceiver  46  may use an antenna to receive out-of-band signals from device  12 . In-band transmissions between devices  12  and  24  may be performed using coils  36  and  48 . With one illustrative configuration, frequency-shift keying (FSK) is used to convey in-band data from device  12  to device  24  and amplitude-shift keying (ASK) is used to convey in-band data from device  24  to device  12 . Power may be conveyed wirelessly from device  12  to device  24  during these FSK and ASK transmissions. 
     It is desirable for power transmitting device  12  and power receiving device  24  to be able to communicate information such as received power, states of charge, and so forth, to control wireless power transfer. However, the above-described technology need not involve the transmission of personally identifiable information in order to function. Out of an abundance of caution, it is noted that to the extent that any implementation of this charging technology involves the use of personally identifiable information, implementers 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. 
     Control circuitry  16  has external object measurement circuitry  41  that may be used to detect external objects adjacent to device  12  (e.g., on the top of a charging mat or, if desired, to detect objects adjacent to the coupling surface of a charging puck). Circuitry  41  can detect foreign objects such as coils, paper clips, and other metallic objects and can detect the presence of wireless power receiving devices  24  (e.g., circuitry  41  can detect the presence of one or more coils  48 ). During object detection and characterization operations, external object measurement circuitry  41  can be used to make measurements on coils  36  to determine whether any devices  24  are present on device  12 . 
     In an illustrative arrangement, measurement circuitry  41  of control circuitry  16  contains signal generator circuitry (e.g., oscillator circuitry for generating AC probe signals at one or more probe frequencies, a pulse generator that can create impulses so that impulse responses can be measured to gather inductance information, Q-factor information, etc.) and signal detection circuitry (e.g., filters, analog-to-digital converters, impulse response measurement circuits, etc.). During measurement operations, switching circuitry in device  12  (e.g., in the puck of device  12 ) may be adjusted by control circuitry  16  to switch each of coils  36  into use. As each coil  36  is selectively switched into use, control circuitry  16  uses the signal generator circuitry of signal measurement circuitry  41  to apply a probe signal to that coil while using the signal detection circuitry of signal measurement circuitry  41  to measure a corresponding response. Measurement circuitry  43  in control circuitry  30  and/or in control circuitry  16  may also be used in making current and voltage measurements (e.g., so that this information can be used by device  24  and/or device  12 ). 
       FIG. 2  is a circuit diagram of illustrative wireless charging circuitry for system  8 . As shown in  FIG. 2 , circuitry  52  may include inverter circuitry such as one or more inverters  61  or other drive circuitry that produces wireless power signals that are transmitted through an output circuit that includes one or more coils  36  and capacitors such as capacitor  70 . In some embodiments, device  12  may include multiple individually controlled inverters  61 , each of which supplies drive signals to a respective coil  36 . In other embodiments, an inverter  61  is shared between multiple coils  36  using switching circuitry. 
     During operation, control signals for inverter(s)  61  are provided by control circuitry  16  at control input  74 . A single inverter  61  and single coil  36  is shown in the example of  FIG. 2 , but multiple inverters  61  and multiple coils  36  may be used, if desired. In a multiple coil configuration, switching circuitry (e.g., multiplexer circuitry) can be used to couple a single inverter  61  to multiple coils  36  and/or each coil  36  may be coupled to a respective inverter  61 . During wireless power transmission operations, transistors in one or more selected inverters  61  are driven by AC control signals from control circuitry  16 . The relative phase between the inverters can be adjusted dynamically (e.g., a pair of inverters  61  may produce output signals in phase or out of phase (e.g., 180° out of phase). 
     The application of drive signals using inverter(s)  61  (e.g., transistors or other switches in circuitry  52 ) causes the output circuits formed from selected coils  36  and capacitors  70  to produce alternating-current electromagnetic fields (signals  44 ) that are received by wireless power receiving circuitry  54  using a wireless power receiving circuit formed from one or more coils  48  and one or more capacitors  72  in device  24 . 
     If desired, the relative phase between driven coils  36  (e.g., the phase of one of coils  36  that is being driven relative to another adjacent one of coils  36  that is being driven) may be adjusted by control circuitry  16  to help enhance wireless power transfer between device  12  and device  24 . Rectifier circuitry  50  is coupled to one or more coils  48  (e.g., a pair of coils) and converts received power from AC to DC and supplies a corresponding direct current output voltage Vrect across rectifier output terminals  76  for powering load circuitry in device  24  (e.g., for charging battery  58 , for powering a display and/or other input-output devices  56 , and/or for powering other components). A single coil  48  or multiple coils  48  may be included in device  24 . In an illustrative configuration, device  24  may be a wristwatch or other portable device with at least two coils  48 . These two (or more) coils  48  may be used together when receiving wireless power. Other configurations may be used, if desired. 
       FIG. 3  is a cross-sectional side view of system  8  in an illustrative configuration in which wireless power transmitting device  12  is a wireless charging puck and in which wireless power receiving device  24  is a wristwatch, as an example. As shown in  FIG. 3 , device  12  has a device housing  90  (e.g., a disk-shaped puck housing formed form polymer, other dielectric material, and/or other materials). Device housing  90  may house a device microcontroller for communicating with plug  94 , DC-DC power converter circuitry such as a step-down voltage converter (e.g., a buck converter), voltage regulator circuitry such as a low-dropout (LDO) regulator, wireless power transmitting circuitry such as inverter  61  (see  FIG. 2 ), coil(s)  36 , and capacitor  70 , near-field communications (NFC) circuitry for communicating with power receiving device  24 , over-temperature protection (OTP) circuitry such as a temperature sensor, debug circuitry, filter circuitry, magnetic alignment structures such as magnets for attracting device  12  during charging operations, and/or other power transmitting device components. 
     Cable  92  is coupled to device housing  90  and provides power to coil(s)  36 . One end of cable  92  may be pigtailed to housing  90 . The opposing end of cable  92  is terminated using plug  94 . Plug  94  has a boot portion  98  sometimes referred to as the “boot” of the plug. Boot  98 , which may sometimes be referred to as a connector boot, may be formed from polymer, metal, and/or other materials and may have an interior region configured to house electrical components (e.g., integrated circuits, discrete components such as transistors, printed circuits, etc.). Boot  98  has a first end connected to cable  92  and a second end connected to a connector portion  96  (sometimes referred to as the “connector” of the plug). Connector  96  may include 24 pins, 10-30 pins, 10 or more pins, 20 or more pins, 30 or more pins, 40 or more pins, 50 or more pins, or any suitable number of pins supported within a connector housing. The pins within connector  96  are configured to mate with corresponding pins in port  102  of external equipment such as device  100 . Device  100  may be a stand-alone power adapter, an electronic device such as a computer, or other equipment that provides DC power to plug  94  through port  102 . Port  102  may be, for example, a USB port (e.g., a USB type-C port, a USB 4.0 port, a USB 3.0 port, a USB 2.0 port, a micro-USB port, etc.) or a Lightning connector port. Plug  96  having a connector protruding from boot  98  may be referred to as a male plug. Plug  96  can be a reversible plug (i.e., a plug that can be mated with a corresponding connector port in at least two different and symmetrical orientations). 
     During normal operation of system  8 , power receiving device  24  may be placed on the charging surface of power transmitting device  12 . Device  24  and device  12  may have magnets (and/or magnetic material such as iron). For example, device  24  may have a magnet and device  12  may have a corresponding mating magnet. These magnets attract each other and thereby hold devices  12  and  24  together during charging. 
     Boot  98  may have a boot housing that houses various electrical components. The boot housing may house a boot microcontroller for communicating with the device microcontroller in housing  90 , DC-DC power converter circuitry such as a step-up voltage converter (e.g., a boost converter), voltage regulator circuitry such as a low-dropout (LDO) regulator, electronic fuse circuitry such as an e-fuse or fuse for providing overcurrent protection when detecting short circuits, overloading, mismatched loads, or other device failure events, filter circuitry, and/or other boot components.  FIG. 4A  is a cross-sectional side view of plug  94 . As shown in  FIG. 4A , boot  98  may include a printed circuit board  112  on which multiple electrical components can be mounted. Printed circuit board  112  may be coplanar with the X-Y plane. Boot  98  may therefore have a thickness that extends along the Z-axis. 
     As described above, power converter circuitry may be disposed within boot  98 . Power converter circuitry such as a step-up voltage converter (e.g., a boost converter) may include relatively large components such as a large power converter inductor and large power converter capacitors. To optimize for power density, the power converter inductors and capacitors may be implemented as relatively tall passive components within boot  98 . There is, however, a limited amount of space within boot  98  to house the various electrical components. It can therefore be challenging to fit all the requisite boot electronics along with power converter circuitry within the limited space inside a boot housing. 
     To accommodate all of the components within boot  98 , printed circuit board  112  may be offset in the Z-direction so that the taller electrical components can be disposed on one side of board  112  and the shorter electrical components can be disposed on the opposing side of board  112 . Plug  94  may have a center plane  110  that divides connector  96  and boot  98  in half. Center plane  110  is parallel to the X-Y plane. In the example of  FIG. 4A , printed circuit board  112  is shifted up in the Z direction above plane  110  so that board  112  is positioned closer to the upper wall  99 - 1  of the boot housing and is thus positioned farther away from the lower wall  99 - 2  of the boot housing. The taller components such as power converter inductor  122 , power converter capacitors  124  (e.g., low noise capacitors), and other taller passive components (e.g., resistors and/or other load components) may be mounted on the lower surface  116  of the printed circuit board. A boot microcontroller and other relatively shorter semiconductor components  120  may be mounted on the top surface  114  of the printed circuit board. Arranged in this way, the overall size of boot  98  can be minimized. 
     The taller components (e.g., components  122  and  124 ) disposed on the bottom surface  116  of the printed circuit board may be at least 10%, 20%, 50%, 100%, 10-100%, 100-200%, 200-300%, 300-400%, 400-500% 100-500%, or more than 500% taller than the shorter components (e.g., components  120 ) disposed on the top surface  114  of the printed circuit board. The heights of the taller components can vary. The heights of the shorter components can vary. Depending on the relative height of these components, the distance between board  112  and the lower boot wall  99 - 2  may be at least 10%, 20%, 10-50%, 50-100% 100-200%, 200-300%, 300-400%, 400-500%, 100-500%, or more than 500% greater than the distance between board  112  and the upper boot wall  99 - 1 . Any number of taller components can be mounted on the side of board  112  with more available Z-height. Any number of shorter components can be mounted on the side of board  112  with more limited Z-height. 
     The example of  FIG. 4A  in which printed circuit board  112  is positioned closer to the upper boot housing wall is merely illustrative.  FIG. 4B  illustrates another suitable embodiment in which printed circuit board  112  is positioned closer to the lower boot housing wall. As shown in  FIG. 4B , printed circuit board  112  is shifted downwards in the Z direction below plane  110  so that board  112  is closer to the lower wall  99 - 2  of the boot housing and is thus farther away from the upper wall  99 - 1  of the boot housing. Configured in this way, the taller components such as power converter inductor  122 , power converter capacitors  124 , and other taller passive components (e.g., resistors and/or other load components) may be mounted on the upper surface of printed circuit board  112 . A boot microcontroller and other relatively shorter semiconductor components  120  may be mounted on the bottom surface of printed circuit board  112 . 
     The taller components (e.g., components  122  and  124 ) disposed on the top surface of the printed circuit board  112  may be at least 10%, 20%, 50%, 100%, 10-100%, 100-200%, 200-300%, 300-400%, 400-500% 100-500%, or more than 500% taller than the shorter components (e.g., components  120 ) disposed on the bottom surface of printed circuit board  112 . The heights of the taller components can vary. The heights of the shorter components can vary. Depending on the relative height of these components, the distance between board  112  and the upper boot wall  99 - 1  may be at least 10%, 20%, 10-50%, 50-100% 100-200%, 200-300%, 300-400%, 400-500%, 100-500%, or more than 500% greater than the distance between board  112  and the lower boot wall  99 - 2 . Any number of taller components can be mounted on the side of board  112  with more available Z-height. Any number of shorter components can be mounted on the side of board  112  with more limited Z-height. 
       FIG. 4C  is a cross-sectional side view showing how underfill material may be disposed under the shorter components but not under the taller components within the boot. As shown in  FIG. 4C , a boot microcontroller  120  is coupled to the upper surface of printed circuit board  112  via a first set of solder bumps  130 , whereas an inductor  122  is coupled to the lower surface of printed circuit board  112  via a second set of solder bumps  132 . Underfill material  134  may be disposed under boot microcontroller  120  and under the other short semiconductor components mounted on the top surface of board  112 . The shorter semiconductor components are sometimes considered “active” electronic components, which generally dissipate more heat than the passive components. The underfill material  134  can help provide better thermal dissipation for the active components within the boot. In contrast, the passive components such as inductor  122  and low noise capacitors  124  disposed on the opposing side of printed circuit board  112  do not need to be underfilled. Underfilling low noise capacitors  124  can also degrade the low noise capability of these capacitors. Thus, not underfilling the taller passive components can help save a processing step while maximizing the performance of the low noise capacitors  124 . 
       FIG. 5A  illustrates another suitable embodiment in which some of the components mounted on a surface of a printed circuit board  113  are underfilled while other components on the surface of board  113  are not underfilled (i.e., are free or devoid of any underfill material). Printed circuit board  113  may represent the printed circuit board disposed within device housing  90  or the printed circuit board  112  disposed within the boot housing. As shown in the top (layout) plan view of  FIG. 5A  looking into the X-Y plane in the Z direction, multiple components such as components  144  and  150  may be mounted on a given surface of board  113 . 
     It may be desirable to underfill components  154  (as shown in the shaded region) while leaving components  144  free of any underfill material. Components  114  might be low acoustic noise capacitors that are coupled to the power supply rail of inverter  61 . Such type of low acoustic noise capacitors should generally not be underfilled for optimal low-noise performance. To prevent the underfill material from reaching components  144  during fabrication, printed circuit board  113  may be provided with an underfill barrier structure such as underfill barrier  142 . Underfill barrier  142  may be formed from metal (e.g., copper, aluminum, tungsten, silver, etc.), dielectric, or other suitable semiconductor material that can be configured to block underfill material from entering region  140  in which components  144  are arranged. Underfill barrier  142  should be disposed prior to depositing the underfill material. Region  140  may therefore sometimes be referred to as an underfill-free area or an underfill-less trench region. 
     The example of  FIG. 5A  in which the underfill-free trench region  140  is at a corner of printed circuit board  113  is merely illustrative.  FIG. 5B  shows another suitable embodiment in which the underfill-free trench region  140  is away from the edge of printed circuit board  113 . As shown in  FIG. 5B , underfill barrier  142  may completely surround region  140  so as to form a moat-like structure around region  140 . Any number of components  144  may be arranged within region  140 . Although the shape of region  140  is shown as being rectangular, the shape of region  140  can be any suitable shape (e.g., a square shape, a triangular shape, a shape with one or more curved edges, a shape with curved and straight edges, a circular shape, an elliptical shape, an irregular shape, etc.). 
     The examples of  FIGS. 5A and 5B  in which there is one region  140  on a surface of printed circuit board  113  is merely illustrative. In general, one or more regions  140  can be located on the top and/or bottom surface of printed circuit board  113 .  FIG. 5C  illustrates another suitable embodiment in which at least two underfill-free trench regions are formed on printed circuit board  113 . As shown in  FIG. 5C , a first region  140 - 1  may be located at a corner of board  113 , whereas a second region  140 - 2  may be located closer to the center of board  113 . Region  140 - 1  may have a first underfill barrier  142  located on only two sides of region  140 - 1 . Region  140 - 2  may have a second underfill barrier  142  (e.g., a copper ring) located on all four sides of region  140 - 2 . Any number of components  144  may be arranged within regions  140 - 1  and  140 - 2 . Regions  140 - 1  and  140 - 2  can have any shape. As another example, printed circuit board  113  may have regions  140  located at two or more corners or three or more corners of board  113 . As another example, printed circuit board  113  may have two or more discrete regions  140 - 2  of the same or different sizes located away from the edges of board  113 . 
     The embodiments of  FIGS. 5A, 5B, and 5C  can be combined with the embodiments of  FIGS. 4A, 4B, and 4C  (i.e., the embodiments of  FIGS. 4 and 5  are not mutually exclusive). For example, one or more regions  140  may be located at the side of printed circuit board  112  on which the shorter underfilled components are mounted. If desired, at least some of the taller non-underfilled components disposed on the opposing surface of board  112  may be surrounded by an underfill barrier structure  142 . 
     In accordance with another embodiment, cable  92  may (as an example) be a 7-wire cable. Cable  92  may have a length that is equal to 1 meter, less than 1 meter, greater than 1 meter, 50-100 cm, 10-50 cm, 100-150 cm, 150-200 cm, or other suitable length.  FIG. 6A  shows a cross-sectional view of cable  92  having seven wires, which include two power (PWR) wires (e.g., wires configured to convey power supply signals such as positive power supply voltages and ground power supply voltages), an interrupt (INT) signal wire (e.g., a wire for conveying an interrupt signal, a status signal, or other control signal), a differential signal path (e.g., a differential signal path having a positive signal wire D+ and an associated negative signal wire D−), and at least two single-ended communication wires SDA and SCL. Differential wires D+ and D− may serve collectively as a high-speed data path to convey information during firmware updates (as an example). Wires SDA and SCL may be a serial data line and a serial clock line, respectively, for the I 2 C bus interface. If care is not taken, signal crosstalk may exist between wires SDA and SCL. 
     To mitigate signal crosstalk between wires SDA and SCL, the differential signal path may be interposed between wires SDA and SCL such that the amount of capacitive coupling from wire SDA to the differential path is equal to the amount of capacitive coupling from wire SCL to the differential path. In the example of  FIG. 6A , wire SCL may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 1  and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 1 . Similarly, wire SDA may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 2  and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 2 . 
     These wires should be arranged such that Cp 1  is equal to Cp 2  and such that Cn 1  is equal to Cn 2 . To accomplish this, the distance between SCL and D+ should be equal to the distance between SDA and D+ (e.g., so that Cp 1 =Cp 2 ). Similarly, the distance between SCL and D− should be equal to the distance between SDA and D− (e.g., so that Cn 1 =Cn 2 ). Arranged in this way, the differential signal wires D+ and D− can cancel out or minimize any signal crosstalk between the serial communication wires SCL and SDA. 
     The example of  FIG. 6A  in which the distance between SCL and D+ is equal to the distance between SCL and D− is merely illustrative.  FIG. 6B  shows another suitable embodiment where the distance between SCL and D+ is not equal to the distance between SCL and D−. As shown in  FIG. 6B , the position of wires INT and D− are swapped relative to the cabling arrangement of  FIG. 6A . In the example of  FIG. 6B , wire SCL may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 1  and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 1 ′. Similarly, wire SDA may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 2  and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 2 ′. 
     These wires should be arranged such that Cp 1  is equal to Cp 2  and such that Cn 1 ′ is equal to Cn 2 ′. To accomplish this, the distance between SCL and D+ should be equal to the distance between SDA and D+ (e.g., so that Cp 1 =Cp 2 ). Similarly, the distance between SCL and D− should be equal to the distance between SDA and D− (e.g., so that Cn 1 ′=Cn 2 ′). Arranged in this way, the differential signal wires D+ and D− can cancel out or minimize any signal crosstalk between the serial communication wires SCL and SDA. 
     The example of  FIG. 6B  in which wires SCL and SDA are arranged closer to wire D+ than to wire D− is merely illustrative.  FIG. 6C  shows another suitable embodiment where wires SCL and SDA are arranged closer to wire D− than to wire D+. As shown in  FIG. 6C , the position of wires SCL and SDA are swapped with the PWR wires relative to the cabling arrangement of  FIG. 6A . In the example of  FIG. 6C , wire SCL may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 1 ′ and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 1 . Similarly, wire SDA may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 2 ′ and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 2 . 
     These wires should be arranged such that Cp 1 ′ is equal to Cp 2 ′ and such that Cn 1  is equal to Cn 2 . To accomplish this, the distance between wires SCL and D+ should be equal to the distance between SDA and D+ (e.g., so that Cp 1 ′=Cp 2 ′). Similarly, the distance between SCL and D− should be equal to the distance between SDA and D− (e.g., so that Cn 1 =Cn 2 ). Arranged in this way, the differential signal wires D+ and D− can cancel out or minimize any signal crosstalk between the serial communication wires SCL and SDA. 
     The example of  FIGS. 6A-6C  in which cable  92  includes only seven wires is merely illustrative.  FIG. 6D  illustrates another suitable embodiment in which cable  92  includes five wires. As shown in  FIG. 6D , cable  92  may include a differential signal path with wires D+ and D−, a power line PWR, and serial signal wires SCL and SDA. In the example of  FIG. 6D , wire SCL may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 1  and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 1 . Similarly, wire SDA may be capacitively coupled to positive differential wire D+ by a parasitic amount Cp 2  and may be capacitively coupled to negative differential wire D− by a parasitic amount Cn 2 . 
     These wires should be arranged such that Cp 1  is equal to Cp 2  and such that Cn 1  is equal to Cn 2 . To accomplish this, the distance between wires SCL and D+ should be equal to the distance between SDA and D+ (e.g., so that Cp 1 =Cp 2 ). Similarly, the distance between SCL and D− should be equal to the distance between SDA and D− (e.g., so that Cn 1 =Cn 2 ). Arranged in this way, the differential signal wires D+ and D− can cancel out or minimize any signal crosstalk between the serial communication wires SCL and SDA. 
     In general, cable  92  may include any suitable number of wires (e.g., four or more wires, five or more wires, six or more wires, seven or more wires, eight or more wires, 5-10 wires, 10 or more wires, etc.). The example of  FIGS. 6A-6D  having I 2 C serial bus wires SCL and SDA is merely illustrative. In general, cable  92  may include two or more single-ended wires that convey information using any suitable serial communication standard/protocol. These single-ended wires can be separated by one or more differential signal paths to reduce crosstalk. The level of crosstalk can be minimized by ensuring that each of the single-ended wires are capacitively coupled to the differential path by an equivalent amount. 
     In accordance with another embodiment, heartbeat signals may be conveyed between boot  98  and power transmitting device  12  so that boot  98  can know that device  12  is still connected or operating normally and/or vice versa.  FIG. 7A  shows how boot  98  has a boot microcontroller  200  (sometimes referred to as being part of boot control circuitry) configured to send and/or receive heartbeat signals to and from power transmitting device  12 . Boot  98  may also include an electronic fuse (e-fuse or fuse circuitry)  204  configured to provide overcurrent protection in response to detecting when device  12  is overheating, when device  12  is disconnected from boot  98 , when a short circuit in boot  98  and/or device  12  has occurred, when there is overloading or mismatched loads, and/or other device failure events. When such failure events occur, e-fuse  204  may be latched off to stop boot  98  from further providing power to device  12 . 
     In one example, boot microcontroller  200  may transmit heartbeat signals, via cable  92 , to device  12  to let device  12  know that the boot is still functioning properly. Device  12  may include a device microcontroller  202  (sometimes referred to as being part of the device control circuitry  16  of  FIG. 1 ) configured to send heartbeat signals to boot  98  via cable  92  to let boot  98  know that device  12  is still functioning properly. In other words, heartbeat signals can be conveyed between boot  98  and device  12  in both directions. In another example, only device  12  may send heartbeat signals to boot  98  (i.e., boot  98  may not send any heartbeat signals to device  12 ). In yet another example, only boot  98  may send heartbeat signals to device  12  (i.e., device  12  may not send any heartbeat signals to boot  98 ). 
     Power transmitting device  12  may be provided with thermal protection hardware including a temperature sensor  206  coupled to device microcontroller  202 . Temperature sensor  206  may measure the temperature of components housed within device housing  90  (see  FIG. 3 ) and may output a temperature sensor value. When the temperature sensor value exceeds a predetermined threshold, device microcontroller  202  may stop sending heartbeat signals back to boot microcontroller  200 . As a result, boot  98  may latch off fuse circuitry  204  and may stop providing power to device  12 . 
       FIG. 7B  is a flow chart of illustrative steps for using boot  98  to communicate with power transmitting device  12 . At step  210 , boot  98  can optionally transmit a heartbeat signal to power transmitting device  12  (e.g., a wireless charging puck). At step  212 , boot  98  may detect a heartbeat signal transmitted from power transmitting device  12 . If boot  98  detects such heartbeat signal from device  12 , boot  98  continues to operate with power transmitting device  12  (step  214 ). 
     If, however, boot  98  does not detect a heartbeat signal from power transmitting device  12 , boot  98  may wait T seconds before restarting to optionally send another heartbeat signal to device  12  (see step  216 ). Value T may be 1 second, 2 seconds, 3 seconds, 4 seconds, 1-5 seconds, 1-10 seconds, greater than 1 second, less than 1 second, or other suitable wait time that can optionally be programmed by boot microcontroller  200 . 
     If boot  98  again does not to detect a heartbeat signal from power transmitting device  12 , boot  98  will now assume that device  12  is disconnected or is otherwise disabled and will proceed to shut off the power, such as by latching off fuse circuitry  204  at step  218 . 
       FIG. 7C  is a flow chart of illustrative steps for using power transmitting device  12  to communicate with boot  98 . At step  230 , power transmitting device  12  (e.g., a wireless charging puck) may transmit a heartbeat signal to boot  98 . Power transmitting device  12  may periodically send heartbeat signals to boot  98 . For example, power transmitting device  12  may be configured to send a heartbeat signal to boot  98  at least once per second (1 Hz or more), at least twice per second (2 Hz or more), at least three times per second (3 Hz or more), at least 4 times per second (4 Hz or more), at least 5 times per second (5 Hz or more), 2-10 times per second, more than 10 times per second, at least once every two seconds, at least once every three seconds, at least once every four seconds, at least once every five seconds, at least once every 1-5 seconds, at least once every 5-10 seconds, or at other suitable periodicity to boot  98  during operation. 
     At step  232 , temperature sensor  206  (see  FIG. 7A ) may detect an output by sensor  206  that exceeds a predetermined threshold value. In response thereto, power transmitting device  12  may prevent device microcontroller  202  from outputting a heartbeat signal to boot  98  to mimic a wire disconnection (at step  234 ). As a result, boot microcontroller  200  will no longer detect any heartbeats from device  12 , which causes power to be shut off as described in connection with  FIG. 7B . Power may later resume, when the temperature value from sensor  206  is below another threshold value, at which time device microcontroller  202  resumes sending heartbeats to boot  98 . 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20201201
Publication Date: 20221018
Grant Date: 20221018
Priority Date: 20201006
Inventors: Thirumalai Ananthan Pillai, Srinivasa V.
HACK, PAUL J.
RASMUSSEN, Timothy J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/0042", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J2207/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/402", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M7/003", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01F38/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/005", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 80931826