Qi Wireless Charging

[-Gamah]

Hi guys! Long time eevblog viewer/lurker, first time poster...  I got this cheap hockey puck charger from amazon for $20 and it works great except for the annoying beep... I pried it open (to remove the speaker) and much to my surprise found a rather elaborate PCB for what I presumed would be some power components, and a coil... I found a data sheet (4shared link below) but I'm not too technical, can anyone explain to me the need for such complexity in laymans terms?

From what I had expected it should have been similar to a prox card on the inside, just with power for the coil. Clicking the picture should get you the full 13MP version.

Rest assured, I was able to identify and--ahem--neutralize the speaker, charging away happily now.

http://www.4shared.com/web/preview/doc/ApMiFn2vce?

[-Gamah]

Aw I hoped this would be more interesting.

[dentaku]

There's actually an NE555 in there

I would be interesting to see if the Nokia Lumia Qi chargers are any different on the inside.

[-Gamah]

I've been contemplating having one delivered to the mailbag to see Dave probe around both the circuit and RF stuff going on... from what little I was able to decipher from the spec sheet it actually communicates with the phone/battery?

[free_electron]

Qi uses a bidirectional protocol across the magnetic link to figure out what the target needs.
The early Qi implementations are all big and bulky and contain lots of parts.

Qi has now been integrated into a single coil and chip.