1 Wireless Power Consortium

The Wireless Power Consortium has developed wireless power standards to support multiple ecosystems. The Qi standard defines a complete ecosystem for the deployment of wireless charging for mobile devices. The Ki standard extends wireless power to the kitchen, enabling cordless operation of appliances with power requirements up to 2200 watts.

Starting with version 1.3 of the Qi specification, authentication was defined as a requirement for chargers that wish to charge at a power level higher than 5W. Version 1.3 of the specification allows charging of mobile devices up to 15W. All chargers are allowed to initially charge at the 5W level without authentication. Authentication must occur to allow charging at a level of higher than 5W. Starting with the Qi 2.2 specification, the power level can be increased up to 25W, with even higher power level standards in definition and development. Qi 2.x also supports the Magnetic Power profile. There is no difference in the authentication requirements.

The Ki standard is for powering cordless kitchen appliances. Multiple power levels have been defined up to 2200W. The Ki standard has leveraged the work of Qi and uses the same authentication protocol. The Ki protocol does use a different root key and root certificate. In addition, the Ki protocol uses out-of-band NFC communication to communicate between the transmitter and receiver and allows for mutual autnehtication of the transmitter and receiver.

Each of these ecosystems requires the following to create a chain of trust from the root to the WPC transmitter.
  1. WPC root certificate – Consists of the root public key and root certificate. The Qi root public key is distinct from the Ki root public key.
  2. WPC manufacturing certificate – Consists of a manufacturing certificate signed by the private key of the root certificate.
  3. WPC product unit certificate – Consists of the product unit certificate signed by the private key of the WPC manufacturing certificate.

The WPC certificates follow the X.509 format. For WPC Slots 0 and 1, the certificate format is fixed. For WPC Slots 2 and 3, the format is not defined and allows for proprietary use of these certificate chain slots.

To participate in one or both of the WPC wireless charging ecosystems, one must be a member of the Wireless Power Consortium. Each ecosystem is unique and requires a separate membership fee. Additional information on the standards and on the consortium can be found on the WPC website: www.wirelesspowerconsortium.com/.