Wireless Power Consortium Eyes Sound Docks That Can Charge Cellphones

Furniture with built-in cellphone charging capability is one of the long-term visions of the Wireless Power Consortium (WPC), and the group has taken a step toward that vision with an under-tabletop transmission method announced last month, Menno Treffers, chairman of WPC, told Consumer Electronics Daily. The consortium said a charger using its Qi specification can deliver 5 watts through a 40-mm tabletop into a Qi receiver using magnetic resonance.

WPC was formed by companies that were experimenting with putting wireless charging capability into phones with the goal of developing a standard for wireless inductive charging to eliminate the need for multiple chargers for phones and accessories, Treffers said. “Consumers don’t like special cradles for different devices,” Treffers said, “and they perceive little value in wireless charging if it means different cradles for different devices."

One of benefits of Qi is energy savings over “phantom” power use in wired charging environments where chargers are typically left plugged in after a phone is removed, Treffers said. In inductive charging, a transmitter awaits a signal from a receiver that needs power. When it detects a receiver, the transmitter sends electricity through a transmitting coil, creating an electromagnetic field with a specific frequency. The receiving coil, designed to accept energy at that frequency, turns the energy into an electrical charge. When the receiver’s battery is full, the receiving coil tells the transmitter to stop sending energy, effectively putting the transmitter into standby, according to documentation from member company Energizer.

WPC’s open Qi spec is currently found on some 60 products primarily for the Japan market, which have been certified and bear a logo indicating the product is Qi-compatible. Most of the cellphone products have been certified in the last six months, Treffers said. Qi products in the U.S. currently take the form of mobile phone sleeve chargers such as Energizer’s $34.99 chargers for the Blackberry Curve and 3G iPhone or Energizer “pad” chargers on which consumers place devices to be charged.

The Qi standard is evolving, Treffers said. The organization’s 109 members “keep finding different ways to transmit power from transmitters to receivers,” he said. Despite the continual advances, the goal is not to some day “charge through the air,” Treffers said. “That explicitly is not the method we use,” he said. Although it’s technically possible to charge a device wirelessly from across a room, the potential electromagnetic field exposure “is considered unsafe” and “brings up all kinds of concerns from consumers and regulators,” he said.

One of the issues affecting adoption by phone makers is embedding a Qi receiver into a phone without adding to the thickness of the device. In addition to the Qi chip, electrical coils and magnetic shielding have to be incorporated in a handset. Manufacturers have come up with ways to address the issue, Treffers said, through choice of materials, coil choices and other types of “product optimization."

In addition to Energizer, WPC member companies include Haier, HTC, LG, Nokia, Panasonic, Research In Motion, Samsung, Sanyo and Verizon, with Imation, Ricoh and TDK also joining just last week, Treffers said. One conspicuous absence from the WPC member list is Apple, which, Treffers observed, operates within “its own ecosystem.” If Apple were to come out with wireless charging capability in its phone, it would likely be proprietary, Treffers noted.

Long term, Treffers doesn’t believe there’s room for different wireless charging standards because of the integration the WPC hopes to achieve outside of the device world, he said. If things advance the way WPC envisions, long term Qi transmitters will be integrated into furniture, including in hotel rooms and offices, along with CE products such as alarm clocks and music docking stations with loudspeakers. An office building isn’t likely to accommodate two wireless charging standards, he said. The Energizer charger currently sold at Best Buy and Walmart uses a sleeve specifically designed to fit the iPhone.

Before the conservative furniture industry will consider building anything electronic into its products, a “significant number” of mobile phones will have to be equipped with the Qi technology, Treffers conceded, and Apple’s absence from the consortium could be a huge obstacle to acceptance. “Technically it’s possible immediately” to incorporate Qi charging capability into furniture, but “business decisions will be made on a large installed base of cellphones,” he said.

A WPC challenge is to manage the “the constant update of new technologies” that members continue to submit to the specification, Treffers said. Proving the technologies are compatible and reliable is an “operational challenge,” he said. Initially, the standard covers 5-watt-and-under applications but medium- and high-power solutions are being studied. That could open up “the possibility of developing interoperable wireless power solutions across a broad spectrum of power needs and brands,” according to the WPC website.

Panasonic recently launched a Blu-ray player in Japan with a built-in Qi charger that can power a digital camera while the camera transmits photos or videos to the Blu-ray player, Treffers said. Down the road, other products on the receiver side could include cameras and game player remote controls, Treffers said. “As soon as we have an installed base of chargers, it becomes attractive to add Qi to anything with a battery,” he said. A future goal is to enable less-exacting positioning requirements so a phone could be placed “anywhere on a table and it will still charge,” he said.