NFC Forum Candidate Technical Specifications
Candidate Technical Specifications
NFC Forum Candidate Technical Specifications are very mature technical specifications whose final adoption is delayed so as to allow verification of its quality, to progress on related test specifications, or the like. Candidate Technical Specifications have different licensing restrictions than adopted Technical Specifications.
Wireless Charging (WLC) Candidate Technical Specification
The Wireless Charging Candidate Technical Specification (WLC) makes it possible to wirelessly charge NFC-enabled devices at a power transfer rate of up to one watt. The WLC enables a single antenna in the NFC-enabled device to manage both communications and charging. This solution makes it easier and more convenient to charge low-power IoT devices such as smart watches, fitness trackers, headsets and other consumer devices.
This NFC specification uses the 13.56 MHz base frequency and leverages the NFC communication link to control the power transfer. NFC technology is unique in that it allows the transfer of power to an NFC tag to enable communication by providing a constant carrier signal. The WLC specification extends this communication functionality of NFC technology to enable wireless charging.
The WLC specification ensures a safe charging process between two NFC-enabled devices in either static or negotiated modes. Static mode uses standard radio frequency (RF) field strength and provides a consistent power level. Negotiated mode uses a higher RF field supporting four power transfer classes of 250, 500, 750 and 1000 milliwatts.