Q&A: What product managers need to know about NFC Wireless Charging

NFC technology is simple and easy to use across a host of use cases. Users hold NFC-enabled devices and tags in close proximity to each other to access services, interact with content, set up connections, make payments, or present tickets. An especially promising emerging use case is NFC wirelessly charging.

The NFC Forum Wireless Charging Specification gives product designers the roadmap they need to create secure, interoperable NFC Wireless Charging solutions. Wireless charging is viewed by many in the NFC ecosystem as the next big leap beyond contactless payments. This Q&A discusses the key characteristics, benefits, and requirements of the specification.

What is wireless charging?

Wireless charging is the transfer of electrical energy from an outlet or source to a device without the need for a connecting cable. NFC is one of many proximity technologies that can eliminate the need for each individual device to have its own plug, adaptor, or extension.

Why do we need wireless charging?

The versatility and functional benefits of wireless charging is clear. Not only does it deliver an intuitive, seamless charging experience for consumers, by eliminating the need to produce charging cables it reduces the amount of material used, and by extension the waste produced, by the smart device ecosystem. Product designers can also make their devices more robust: with no need for a charging port, a device can be completely sealed. This increases the structural integrity of the device, and eliminates the chance of dust, dirt, rust, and water damage accumulating in charging ports.

What are the benefits of NFC Wireless Charging?

By using NFC as a wireless charging source, product designers can make use of the NFC chipsets and antennas already found in billions of devices, avoiding the need for a separate wireless charging unit. This unlocks benefits for multiple stakeholders:

• Device manufacturers can simplify their products, streamline their designs, and reduce manufacturing costs as a single NFC antenna can be used for transferring data, making payments, and wireless charging.
• Product designers can consider new use cases that do not need constant power. NFC’s power harvesting capabilities can enable a small or low power device to power itself by leveraging the charge of another NFC device within range. Devices such as a smart padlock can be activated simply by a user holding their mobile phone within range. The padlock harvests power from the smartphone, then recognises that the phone has the correct key and unlocks. This lock has the same functionality as a fully powered product but is far more cost and resource efficient to manufacture.
• Consumers are already familiar with NFC technology, meaning that any new solution that uses it is familiar, trusted, and convenient.
• Environmental sustainability goals can be supported because wireless charging solutions don’t require cables, chargers, or disposable batteries.

How is NFC wireless charging different than Qi?

NFC technology was initially developed as a secure data transfer protocol but it has since evolved to support wireless charging. This means that its wireless charging specification is notably different from the other major wireless induction charging standard, Qi.

While both NFC and Qi offer wireless charging capabilities, they serve distinct purposes and find applications in different use cases. Qi uses an induction coil to deliver up to 15W over a distance of 4cm, allowing it to provide rapid charging to many mid-sized devices such as smartphones and tablets.

Meanwhile, NFC Wireless Charging utilizes a much thinner antenna – with a surface area as small as 3mm – to transfer up to 1W of power over a certified compliant range of 5mm. This makes it ideal for compact personal and wearable devices such as wireless earbuds, smartwatches, digital styluses, headsets, and fitness trackers.

For charging on the go, users can use similarly NFC-equipped smartphones as a reverse-wireless charger. To charge their headphones, a user can simply place them on the back of their smartphone with NFC enabled and power will be transferred from the phone to the headphones.  

The NFC Forum is working on increasing NFC charging capability up to 3W, which will substantially expand the technology’s use cases.

What is the Technical Specification?

First launched in May 2020, with version 2.0 released in October 2021, the NFC Forum Wireless Charging Specification enables a single antenna in an NFC-enabled device to manage both communications and charging. It uses 13.56 MHz base frequency and leverages the NFC communication link (magnetic induction) to control the power transfer.  

The Specification ensures a smooth charging process between two NFC-enabled devices in either:

• Static mode – For devices that only require charging and won’t charge other devices. These devices have a very small power function able to operate with standard RF field strength NFC communication. This allows the device receiving the power to announce its wireless charging requirements to the charging device, which charges accordingly.
• Negotiated mode - This uses a higher RF field than a standard NFC communication, supporting four power transfer classes of 250, 500, 750, and 1000 milliwatts. It allows the device receiving the power to request the optimum required power level from the charging device. When the device is charged, the power transfer stops.

Want to learn more? Download the specification.

How is the NFC Forum Wireless Charging Specification supporting members?

The NFC Forum community is bringing all stakeholders together – from silicon vendors, OEMs to application developers, implementers – to achieve its goal of ensuring that NFC wireless charging becomes the de facto standard for powering small IoT and consumer devices.

The NFC Wireless Charging Specification ensures that the technology implemented in any device is interoperable with the broader NFC technology ecosystem. Through testing and certification against this specification, product designers can ensure their products meet these requirements and can then add the NFC Forum Charging Wayfinding mark to the product. This provides users with confirmation of NFC charging functionality while also highlighting the location of the antenna.

The Power of Collaboration

A trusted, interoperable standard for NFC Wireless Charging is the outcome by of international industry cooperation between multiple competing businesses. NFC Forum brings these competitors together to evaluate the long-term needs of the market to shape future specifications for the benefit of the entire ecosystem.

NFC Forum members come from virtually every sector – manufacturers of NFC chips, readers and device; access control; customer engagement; healthcare; IoT; payments; transportation; wearables; wireless charging, and more.

To learn more about the benefits of NFC Wireless Charging for personal devices, download our latest Whitepaper.

Or watch the recording of our webinar on NFC Wireless Charging for wearable and personal devices. The session presented insights from a panel of experts from Huawei, Infineon, NuCurrent, NXP, Panthronics, STMicroelectronics, Zebra Technologies, and Wired & Wireless Technologies Ltd (WAWT).  

Join us in advancing this powerful new use case.