New Wireless Charging Platforms Bypass the Conundrum of Perfectly-Aligned Coils
Apple ultimately canceled its wireless power program because of coil alignment. Three new platforms aim to work around the problem that slowed the tech giant down.
Demand for increased convenience and simpler charging has led to the rapid growth of the wireless charging market, as a recent report from Global Market Insights suggests. Now, the limited flexibility of current charging solutions has led companies to pioneer novel charging platforms.
Diagram of the wireless charging market. Image used courtesy of Global Market Insights
In this article, we'll address the design challenges of wireless charging technology and how a few companies are working around these challenges.
The Challenges of Wireless Charging
Most wireless charging products available are based on the Qi open wireless charging standard developed by the Wireless Power Consortium (WPC). With this standard, power coils embedded in a wireless charger need to align with a device for it to charge.
While the technology works, it limits the distance of wireless charging (devices need to make close contact with the coil) and the number of devices charged by a single wireless charger. Previous attempts at solving some of these problems within the Qi standard have been unsuccessful.
Apple's prototyped solution to these challenges, for example, was to add more coils and overlap them so that no matter where a device is on the mat, it would line up.
The project, however, was canceled last year—likely because the coils interfered with each other, reducing their effectiveness. Each of these coils also needed to be powered and generated a significant amount of heat as a result. Noise generated by the coils also likely interfered with other nearby devices.
Now, a number of new wireless charging platforms that go beyond the Qi standard and take advantage of novel applications of existing electronics technology are starting to come to market. Below, we'll cover three different wireless charging platforms as well as the essential technology and chip design that allows these platforms to work.
GuRu is a newcomer to the wireless charging market that showed off some of their devices, including a robotic wireless charger named "Rovi," earlier this year at CES 2020.
The company's novel approach uses beams of high-frequency radio waves—non-ionizing mm-waves, the same frequency band used by 5G—to charge devices wirelessly. The company's platform intelligently directs radio signals to devices with a small circuit board, called a Recovery Unit, which announces its presence to the power generator and sends information about where the device is and how much power it needs.
According to GuRu CEO, Florian Bohn, the main difference between GuRu technology and comparative wireless charging technology is that GuRu "selectively sends energy to a very small local," sometimes even localizing energy to a one- or two-inch spot for the company's desk product, room product, or mobile product.
GuRu's recovery unit (RU) is comprised of a thin array of circuits attached to a device, which determines energy demands and converts RF beams into electric power. Image used courtesy of GuRu
Bohn explains that GuRu controls mm-wave technology using a number of algorithms to individually control a large array of transmitters for wave localization.
"It’s the same difference between 5G and Wi-Fi," Bohn explains. "Wi-Fi will send energy everywhere. You're picking up a small fraction of it, whereas, with the technology we’re using, you can localize and pinpoint energy exactly where you need it to be."
The company hopes to eventually introduce a system that will allow end-users to manually control when charging beams are active and turn them off when they encounter interference.
Renesas and Panthronics
Renesas Electronics, a developer of wireless power tech, recently announced in a press release that the business was teaming up with Panthronics, a semiconductor company known for its near-field communication (NFC) readers and controllers.
The new partnership designs wireless charging solutions for IoT devices. The two companies plan to use a combination of Renesas's transmitter ICs—which the company uses inside its charging pads as a "single-chip solution" that can drive one or multiple charging coils—and Panthronic's NFC chips, which enable NFC connectivity and communication with IoT devices.
Panthronics' NFC wireless charging IC. Image used courtesy of Panthronics
Using NFC connectivity in this way will enable IoT devices to both charge and communicate using the same antenna—a specific functionality that was approved by the NFC forum early last year.
The technology could be especially useful in charging large numbers of devices at the same time, like in large-scale industrial IoT fleets or in applications such as wireless vehicle charging stations, which Wakefield Research asserts will see significant growth over the next few years.
Aira has designed a wireless charging platform designed to enable charging mats to power devices, regardless of the device's position on the mat.
The company's charging platform uses integrated circuitry and onboard algorithms to activate and deactivate power coils on a matrix based on where a device or devices are on the wireless charger. The chipset relies on some moderately complex programming to control the coil matrix—over 200,000 lines of code as Aira CEO and co-founder Jake Slatnick told Lory Gil from iMore.
Aira's FreePower wireless charger allows users to place their device anywhere on the platform without needing a perfect alignment. Image used courtesy of Aira
In a CES roundup, Forbes revealed that new charging pads from Nomad, a consumer electronics accessory company, integrate Aira's FreePower wireless charging platform into one wireless charger that is capable of charging two smartphones and a smaller device—for example, an AirPod case—at the same time.
New Platforms Re-Invent Wireless Charging
Rapid growth in the wireless charging market, coupled with the limitations of the current leading standard, has led to innovations in wireless charging. For example, some new platforms use programmed chipsets to control matrices of charging coils, while others apply technology like mm-wave and NFC connectivity to deliver power over a distance.
Have you designed wireless charging technology? Share your experiences in the comments below.