Skip the navigation

Samsung uses Qi charging for Galaxy S4, but sees A4WP as the future

March 27, 2013 05:29 AM ET

A4WP's 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.

Grajski 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."

Grajski 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 smartphone & 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 phones using the A4WP specification 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," Grajski said.

covers storage, disaster recovery and business continuity, financial services infrastructure and healthcare IT for Computerworld. Follow Lucas on Twitter at Twitter @lucasmearian or subscribe to Lucas's RSS feed Mearian RSS. His e-mail address is lmearian@computerworld.com.

See more by Lucas Mearian on Computerworld.com.

Read more about Emerging Technologies in Computerworld's Emerging Technologies Topic Center.



Our Commenting Policies
Internet of Things: Get the latest!
Internet of Things

Our new bimonthly Internet of Things newsletter helps you keep pace with the rapidly evolving technologies, trends and developments related to the IoT. Subscribe now and stay up to date!