Up until last week there had been a minimum of 9 Apple inventions regarding AirPower that were made public by the U.S. Patent and Trademark Office (01, 02, 03 and 04 that covered 6 patent applications) This week the US Patent & Trademark Office published a new series of four patent applications from Apple. Three of the patent applications cover different aspects of AirPower while the fourth covers the inductive module found in iPhone 8 and iPhone X.

#1: Wireless Charging System with Inductance Imaging

Apple notes that it can be challenging to regulate the flow of wireless power in a wireless charging system. For example, in a wireless charging system having adjustable operating settings, it can be difficult to determine which settings to use to effectively transmit wireless power to an electronic device.

Apple's invention covers a wireless power transmitting device that has an array of wireless power transmitting coils that overlap a charging surface. The charging surface is configured to receive a wireless power receiving device. The wireless power receiving device has a wireless power receiving coil that receives wireless power signals transmitted by the wireless power transmitting device.

The wireless power receiving device may also contain a communications integrated circuit, display circuitry, or other component that is sensitive to radio-frequency interference, a metal component that can become heated when exposed to wireless power signals, or other sensitive component. The wireless power transmitting device can select a given one of the array of wireless power transmitting coils to transmit the wireless power signals to the wireless power receiving device without exposing a sensitive component in the wireless power receiving device to excessive wireless power signals.

The wireless power transmitting device uses inductance measurement circuitry that is coupled to the coil array to measure coil inductances for the wireless power transmitting coils.

The location and orientation of the wireless receiving device on the charging surface can be determined by analyzing the coil inductances. Information on the location and orientation of the wireless receiving device on the charging surface and information on the location of the sensitive component within the wireless power receiving device can be used to select the given wireless power transmitting coil to transmit wireless power signals to the wireless power receiving device without exposing the sensitive component to excessive wireless power signals.

In Apple's patent FIG. 5 below we're able to see a top view of an illustrative wireless power transmitting device with an array of coils that forms a wireless charging surface

More specifically, in the example of FIG. 5 above, coil #14 of device #10 is overlapping coils C7 and C8. The housing of device has a rectangular footprint (outline when viewed from above). After a wireless link has been established between the device and AirPower (charging mat #12), the device (#10 iPhone) can inform the charging mat of the location of components that are potentially sensitive to exposure from wireless power signals relative to coil #14 and the outline of the device such as sensitive component #160 (e.g. radio-frequency-sensitive components that are sensitive to radio-frequency interference due to the wireless power signals or other sensitive components).

In FIG. 5, the charging mat (AirPower) can weigh competing considerations in selecting which coil to use in transmitting wireless power, such as the desire to enhance wireless coupling between the transmitting coil of AirPower and the wireless receiving coil of the device (e.g. iPhone, Apple Watch) and the desire to avoid exposing sensitive component #160 to wireless power signals.

The resulting coil selection may, as an example, favor a coil such as coil C8 of FIG. 5 that overlaps coil #14 less than coil C7, but that helps minimize exposure of sensitive component #160 to wireless power signals transmitted by AirPower during battery charging operations.

Apple's patent application 20180233954 was filed in Q4 2017. One of the inventors listed on the patent filing is Zaki Moussaoui Ph.D., Director of Power Technology / Systems Architecture.

#2: Wireless Charging System with Protection Circuitry

Patent Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. The wireless power receiving device has a rectifier and a wireless power receiving coil that receives wireless power signals. The rectifier is coupled to an integrated circuit such as a battery charger integrated circuit. One or more capacitors are coupled between input terminals for the rectifier and the wireless power receiving coil. The rectifier has output terminals at which the rectifier provides direct-current output power corresponding to the wireless power signals received with the wireless power receiving coil. Protection circuitry is coupled to one or more nodes located between the wireless power receiving coil and the capacitors. Control circuitry turns on one or more transistors in the protection circuitry in response to measurements made with sensor circuitry coupled to the output terminals.

For more details, dig into Apple's patent application 20180233942.

#3: Wireless Charging System with Start-up Negotiation. Review patent 20180233956 for more details here.

#4: Inductive Module

Patent Abstract: Embodiments describe a wireless power receiving module to receive magnetic flux for wireless power transfer. The wireless power receiving module includes a receiver coil comprising a single length of wire wound into a plurality of turns, an electromagnetic receiver shield coupled to a first side of the receiver coil, a ferrite layer coupled to a second side of the receiver coil opposite of the first side, the ferrite layer positioned to redirect magnetic flux during the charging event to improve charging efficiency, and a thermal mitigation shield comprising a thermally conductive layer adhered to an electrically conductive layer where the electrically conductive layer is coupled to ground, and where the ferrite layer is sandwiched between the thermal mitigation shield and the receiver coil.

For more details, dig into Apple's patent application 20180233951 here.

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