A brief history of the Qi specification
Qi specifications are numbered with three digits: X.Y.Z. For example 1.0.3
- X is called the major revision number. Specifications with the same major revision number are backward and forward compatible.
- Y is called the minor revision number. A change in minor revision number implies that new requirements are introduced while maintaining backward compatibility previously certified products
- Z is called the editorial revision number. Editorial revisions include clarifications, integrate new transmitter designs into one document, and may add new test to the test specifications.
Current version of the Qi specification
The current version of the Qi specification has version number 1.2.4. The Qi specification that is available for public download has version 1.2.3. Version 1.2.4 is available only to members of the Wireless Power Consortium. The public version is always one revision behind the version that is available to members of the Wireless Power Consortium.
History of the Qi specification
- Qi transmitter delivers 5 Watt power into a Qi phone.
- Choice of transmitter designs include single coil transmitter, coil array transmitter, and moving coil transmitter.
- High flexibility in design of Qi receivers
- Limited flexibility in the design of Qi transmitters
- Increased design freedom for transmitters. You can now choose between 12 different transmitter specifications.
- Increased sensitivity of "Foreign Object Detection". This prevents heating of metal objects in the neighborhood of an active transmitter.
- The possibility to power a Qi transmitter with a USB charger.
- Fast charging. The possibility for transmitters to deliver up to 15 Watt power and the option for receivers to obtain up to 15 Watt.
- An improved thermal test for transmitters
- Improved timing requirements
- Changed limits for Foreign Object Detection improve the sensitivity.
- Optional unique identifier for power receivers (WP-ID)