IDT and Intel Join Forces For Wireless Charging

MojoKid writes "Intel has selected Integrated Device Technology (IDT) to develop an integrated transmitter and receiver chipset for the company's Wireless Charging Technology (WCT) based on magnetic resonance technology, it was announced [Wednesday]. The technology won't require you to plop your smartphone or other gear on a special charging mat (based on inductive charging), but you will be able to wirelessly charge your devices from an equipped device like a notebook. In addition, magnetic resonance charging is significantly more efficient than previous generation inductive technologies and it produces less heat build up in the process. Intel didn't say when WCT will appear in shipping products, but promised to update plans and timelines at a later date."

Efficiency

[Thelasko]

Forgive me, but every time I hear about wireless power, I think about how inefficient that sounds. Wouldn't a (more or less) direct connection to the power source be more efficient? Aren't we trying to conserve energy, and improve energy efficiency?

Re:mag field "leakage" problems anyone??

[Bruce Perens]

You walk around all day in a field that is strong enough to physically move a compass needle. As you change position, you do have a changing magnetic field intersecting with that credit card.

Mythbusters can goof, but they are promoting that the way to learn is from experiments and observation. Which is science.

Re:Efficiency

[slew]

Forgive me, but every time I hear about wireless power, I think about how inefficient that sounds. Wouldn't a (more or less) direct connection to the power source be more efficient? Aren't we trying to conserve energy, and improve energy efficiency?

It's important to understand that even a "direct" connect is just a waveguide for an electromagnetic wave. Waveguides can have all sorts of losses (resistive, radiation, etc.) that limit their efficiency. At typical power distribution frequencies resistive losses can be quite large with long narrow wires, although in general with an impedance matched zip-cord, the radiation losses tend to be pretty low. Also direct connect isn't completely direct connect either. Inside that wall-wart is a step-down transformer which is basically a small inductive power transfer (wireless power), which has its own power efficiency issues.

Theoretically, the "free-space" transmission (well not really free-space, but air-space), has the potential to eliminate most of the resistive loss, although in practice there is this basic problem of radiation power loss. This type of tech (resonant magnetic coupling) has a few tweaks to try to help with this problem. First off, there's use of use of near-field evanscent waves which don't propogate very far (evanscent waves are the exponentally decay solution to the em wave equation) keeping most of the power local. Second, there is the use of resonance which reduces the losses and increases the efficiency of power transfer. The combination of these ideas allows pretty good power efficiency. I think you can get about 80% efficiency with near-field (vs 90% for a wall-wart connect). For the small amount of power going to recharge a mobile device, that's not really that much to worry about (if you were trying to power say a TV or a stereo, that would be another thing).