Apple files patent for Bimodal Reverse Recharging System to charge accessories with future iPhone

Jan 2, 2023, 3:07 PM UTC
6 mins read
Apple files patent for Bimodal Reverse Recharging System to charge accessories with future iPhone
(Logo courtesy of Apple)

There have been ongoing rumors that Apple will eventually release an iPhone with reverse charging capabilities to charge accessories. In October 2020 and again in 2021, MacRumors reported on an FCC filing supporting this feature. However, in February 2021, Mark Gurman stated that it was unlikely that the ability to wirelessly recharge accessories would be available in the near future.

On Thursday, the US Patent & Trademark Office published a patent application from Apple detailing a new wireless charging system using bimodal magnetic alignment components to align devices. This system could potentially be implemented on the back of a future iPhone, allowing it to wirelessly charge accessories such as AirPods and their case, the Apple Watch, and more. Apple’s current wireless charging system on the back of the iPhone is limited to a large coil, which cannot charge smaller devices such as the Apple Watch.

In its patent background, Apple notes that wireless charging technologies have been developed that utilize electromagnetic induction to charge portable electronic devices without the need for a cord. For instance, some portable electronic devices can be recharged by placing them on the charging surface of a wireless charger device.

The wireless charger contains a transmitter coil that is powered by an alternating current, generating a time-varying magnetic flux that induces a current in a receiver coil located in the portable electronic device.

The induced current generated by the wireless charger can be used by the portable electronic device to charge its internal battery. Some portable electronic devices are also designed to transmit power wirelessly to other devices, such as accessories.

However, proper alignment of the magnets can sometimes be difficult to achieve. In a video from iDeviceHelp, the process of using Apple’s MagSafe battery pack with wireless charging is demonstrated. However, when the author attempted to charge AirPods in their case, it failed, even though the charging light briefly turned on. The author speculated that this issue could be resolved with a software fix. But a patent application published by Apple last Thursday suggests that the solution may require the use of a new kind of wireless charging battery design with bimodal magnetic alignment components, rather than just a software fix.

Apple notes in its summary that the efficiency of wireless power transfer can be affected by the alignment of the transmitter and receiver coils, among other factors. For example, the transmitter and receiver coils may function optimally when they are aligned coaxially. However, finding the proper alignment can be challenging when the portable electronic device has a flat surface without any guiding features.

Alignment is often achieved through trial and error, with the user adjusting the relative positions of the device and charger and observing the impact on charging performance.

Finding optimal alignment through this process can be time-consuming and the lack of surface features can make it difficult to maintain proper alignment. For example, if the portable electronic device and/or charger are bumped during charging, they may be knocked out of alignment. To address these issues, some electronic devices include magnetic alignment components (e.g., around the inductive coils) that can keep the two devices in the desired alignment. These magnetic alignment systems can have two types of alignment components, known as “primary” and “secondary,” each with a ring of magnets with fixed magnetic polarities that attract each other.

For example, a primary alignment component can have a quad-pole magnetic configuration with inner and outer annular regions that have opposing axial magnetic polarities, while a secondary alignment component can have a dipole magnetic configuration with a radial magnetic orientation. When brought close to each other, the primary and secondary alignment components create a mutually attractive magnetic force that can align the components (and the devices in which they are installed) and/or prevent them from being dislodged from the desired alignment.

In magnetic alignment systems like this, alignment components of the same type (either two primary or two secondaries) repel each other, making it difficult to create a “bimodal” device that can attach interchangeably to devices with either type of magnetic alignment component.

One solution is to omit the magnetic alignment component from the bimodal device, but this means that the device will not benefit from magnetic alignment and attachment.

Another option is to include two separate magnetic alignment components (one primary and one secondary), but this may also require additional inductive coils and other electronic components, which can increase the size, weight, and cost of the device.

Certain embodiments of the present invention relate to bimodal alignment components that can be used in a bimodal device. These components have alignment magnets that can be reoriented or shifted between a first attachment position that is complementary to a primary annular alignment component and a second attachment position that is complementary to a second annular alignment component. This allows a device with a bimodal alignment component to be interchangeably attached to other devices using either a primary or secondary annular alignment component.

Apple’s patent fig. 4 illustrates a simplified exploded view of a bimodal device, while Fig. 7 shows a partial perspective view of a bimodal alignment component. Fig. 22A and 22B above show simplified cross-section views of the bimodal alignment component in two different attachment positions.

Apple files patent for Bimodal Reverse Recharging System to charge accessories with future iPhone
(Image Credit: Patenly Apple)

This is a highly technical patent. Engineers and tech enthusiasts who want to delve into the details can review Apple’s patent application number US 20220416590 A1.

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