Wireless charging has captured the imagination of mobile phone users, designers, and service providers. Now, with the introduction of the 15-watt extension to the Qi specification, a new world of products and capabilities has opened up.
While previously the benefits of wireless charging had been limited to charging mobile phones at five watts (on par with typical wired charging), the convenience and reliability of wireless charging has made it a "must-have" in many smartphone feature check-lists. Recent announcements from IKEA and Samsung have hastened the adoption of this convenient charging technology.
The first new benefit of the increased power is the ability of mobile phone manufacturers and after-market accessory makers to offer wireless fast-charge capability. This new technology goes by various names: Quick Charge 2 from Qualcomm, Adaptive Fast Charging, from Samsung, TurboPower from Motorola, and BoostMaster from Asus. What these charging systems all have in common is that they can take advantage of 15W sources like USB-3 (5V/3A) and new 9V/1.67A chargers.
How fast is this new charging technology? Up to 75% faster than conventional charging. Qualcomm conducted a test that compared three charging approaches. The phones all used a 3300mAh battery and charged for 30 minutes. Following are the results:
- from 0% to 60% with Quick Charge 2.0 (9 volt/1.67 amp, 15W)
- from 0 to 30% with Quick Charge 1.0 (5 volt/2 amp, 10W)
- from 0% to 12% with a conventional charger (5 volt/1 amp 5W)
The latest Qi specification enables device manufacturers to extend this speed to wireless charging. In addition, the 15W extension supports the ability to wirelessly charge tablet computers at rates similar to wired charging. Asus tablets come with 10-watt chargers and Apple iPads come with 12W chargers. That means that these digital marvels can also take advantage of wireless charging without any charging speed tradeoffs.
Larger form-factor electronics like power tools, digital cameras, and test instruments will also benefit from the increased power and decreased charging time made possible by the latest 15W extension to the Qi spec. The key components, transmitter coils, receiver coils, and semiconductors are already available or are in development, so OEMs can be designing fast wireless charging products now.
Let us know how this new spec aligns with your newest product designs in the comments section below.