AirPower was an unreleased wireless charging mat developed by Apple Inc. It was designed to charge up to three devices simultaneously, supporting two Qi devices, such as an iPhone and AirPods, and an Apple Watch. It was announced in September 12, 2017 that it would come to market in early 2018. AirPower failed to materialize, While the project was officially cancelled, Apple's engineers kept filing patents for variants of the AirPower mat and even dreamt up some form of 3D wireless charging box as noted in the patent figure below from a May 2020 patent filing.

Today the U.S. Patent and Trademark Office officially published a patent application from Apple that presents yet another wireless charging pad invention. Although made public today, it was filed back in 2022, well after the project was reportedly killed. Obviously Apple continues to work on a wireless charging mat – even though they stay clear of using the term "mat" anywhere.   

Multi-Coil Wireless Charger

Apple's patent application covers a multi-coil wireless power transfer arrangement can include a magnetic core; first and second wireless power transfer coils positioned adjacent one another above the magnetic core; a third wireless power transfer coil positioned above the first and second wireless power transfer coils; a magnet ring located above the first and second wireless power transfer coils; additional magnetic core material disposed atop the magnetic core and associated with the third wireless power transfer coil, wherein the first and second wireless power transfer coils are separated by a separation distance selected to accommodate the additional magnetic core material; and a segmented metallic shield positioned between the magnet ring and the first and second wireless power transfer coils.

The additional magnetic core material can include a base portion disposed atop the magnetic core and beneath the third wireless power transfer coil and a post portion disposed atop the base portion and within the third wireless power transfer coil. The separation distance can be further selected to reduce coupling between the first or second wireless power transfer coil and the third wireless power transfer coil.

A multi-coil wireless power transfer arrangement can include a magnetic core, first and second wireless power transfer coils positioned adjacent one another above the magnetic core, a third wireless power transfer coil positioned above the first and second wireless power transfer coils, and a magnet array located above the first and second wireless power transfer coils. The first, second, and third wireless power transfer coils can be part of an array of wireless power transfer coils, the array including multiple first and second wireless power transfer coils and multiple third wireless power transfer coils.

The multi-coil wireless power transfer arrangement can further include additional magnetic core material associated with the third wireless power transfer coil. The additional magnetic core material can include at least one base portion disposed atop the magnetic core and beneath the third wireless power transfer coil. The magnetic core material can include at least one post portion disposed atop the base portion and within the third wireless power transfer coil. The additional magnetic core material can be affixed to the magnetic core or formed integrally with the magnetic core. The first and second wireless power transfer coils can be separated by a distance selected to accommodate the additional magnetic core material and/or a distance selected to reduce coupling between the first or second wireless power transfer coil and the third wireless power transfer coil. The first and second wireless power transfer coils can have at least one of a different operating mode or a different operating frequency than the third wireless power transfer coil.

The multi-coil wireless power transfer arrangement can further include a shield positioned beneath the magnet ring. The shield can be a segmented metallic ring. The multi-coil wireless power transfer arrangement can include a shield positioned above the magnet ring. The shield can be a segmented metallic ring.

wireless power transfer device can include power conversion circuitry coupled to a multi-coil wireless power transfer arrangement, and control circuitry coupled to the power conversion circuitry that operates the power conversion circuitry to facilitate wireless power transfer via the multi-coil wireless power transfer arrangement that further includes a magnetic core, first and second wireless power transfer coils positioned adjacent one another above the magnetic core, a third wireless power transfer coil positioned above the first and second wireless power transfer coils, and a magnet ring located above the first and second wireless power transfer coils. The wireless power transfer device can further include additional magnetic core material associated with the third wireless power transfer coil. The first and second wireless power transfer coils can be separated by a distance selected to allow for at least one of accommodating the additional magnetic core material or reducing coupling between the first or second wireless power transfer coil and the third wireless power transfer coil. The first and second wireless power transfer coils can have a different operating mode or a different operating frequency than the third wireless power transfer coil. The control circuitry can be configured to perform foreign object detection by power accounting and to adapt a loss estimation portion of the power accounting based on which of the first, second, or third wireless power transfer coils is in use. The wireless power transfer device can further include a segmented metallic shield positioned between the magnet ring and the first and second wireless power transfer coils.

Apple refers to this device as a multi-coil wireless charger and more particularly "an arrangement" between a wireless power transfer system includes a power transmitter (PTx) #110 that transfers power to a power receiver (PRx) #120 wirelessly, such as via inductive coupling #130 as presented in patent FIG. 1 below.

Apple's patent FIG. 2 above illustrates a coil configuration of a wireless power transfer device. The wireless power transfer device could be a wireless power transmitter, a wireless power receiver, or both, i.e., having a wireless power transfer system that can transmit or receive power wirelessly via the coil arrangement.

As one example, a smartphone could have a bi-directional wireless power transfer system capable of charging the phone's internal battery when acting as a wireless power receiver or charging an accessory device, such as wireless earphones, when acting as a wireless power transmitter.

The amount of power that can be transferred wirelessly and the efficiency of that power transfer can be affected by the relative positioning of the transmit and receive coils and the degree of magnetic coupling between them. Some coil configurations, such as coil configuration #200, can provide improved magnetic coupling and a higher degree of flexibility with respect to such positioning by using multiple coils. In configuration 200 of FIG. 2, three coils 202a, 202b, and 202c are provided.

The three coils 202a, 202b, and 202c may, for example, be arranged in what is called a DDQ configuration. Such a configuration is so named because the lower two coils 202a and 202b are arranged in a shape that is reminiscent of two “D”s, while the third coil 202c is layered above them and operated with an electrical phase angle of 90 degrees with respect to them, thus being a “quadrature” coil.

The DDQ configuration is just one example of how multiple coils could be configured to allow for improved coupling between transmit and receive coils and/or greater alignment tolerance. An additional component of coil configuration #200 can be a magnetic core #201 such as a ferrite “sheet.” Such core elements can provide various advantages, such as steering, directing, containing, or shielding other device components from magnetic flux associated with operation of the wireless power transfer coils.

Additionally, although referred to as a ferrite sheet, the core element need not be strictly planar, nor need it be made from ferrite. Any material with suitable magnetic properties (e.g., magnetic permeability) could be used depending on the requirements of a particular application, and the shape need not be planar. Likewise, any core shape that achieves the various flux directing, steering, containing, or shielding objectives of a particular system could be used. Various multi-coil designs and associated core shapes have been proposed.

To review the full details of this invention, check out patent application 20240186836.

Apple's Inventors

• Adam Schwartz: Director of Engineering
• Ruiyang Lin: Hardware Development Engineer