The WiPower specification, released in January, defines several categories or classes of charger. The categories include charging pads that are the size of a single smartphone and larger pads that are about the size of a half-sheet of letter-sized paper.
Critics of magnetic resonance charging have said that as multiple devices are added to a pad or charging box, the wattage being supplied to each mobile device decreases as the power is shared.
Grajsky said chargers will likely be rated for multiple devices.
"If you put a tablet and a smart phone on a system rated for 5 watts, yeah, the system will try to share that 5 watts across those two devices," he said. "But, if you put two devices on a charger rated for 22 watts, then the tablet and the smart phone will get a full charge."
Grajsky also argued that magnetic induction charging carries with it not only its restricted charging field, but also the drawback that it tends to heat foreign metal objects that come into contact with the charging surface.
"The frequencies at which tightly coupled solutions operate are not that far from the frequencies that are used for conductive cooking," he said. "The tightly coupled solutions today have a problem where they can heat the metal surfaces in the smart phone & or metal objects. The result is that a lot of times [with] the tightly coupled solutions, the foreign object detection either dials back the power or simply turns the power off."
Smartphone manufacturers won't begin shipping WiPower enabled phones and charging pads until next year, Lin said, assuming equipment manufacturers begin production in the second half of this year.
"Our interoperability spec was formalized in January. We're working now to finalize the certification programs that manufacturers will go through in order to create a certified product," Grajsky said.
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