Wireless charging solution

[vinodstanur]

Hi,
If a product is having any wireless charging feature, then will it require any certification or any thing like that?
Is there any simple but most commonly used open hardware wireless battery charging circuits?
I have tried my own simple resonance coupling circuit which works good but it doesn't have any communication feedback and stuff like that. To use that circuit in a product do I need to get any certification from any authority?

 

[crutschow]

Wireless charging systems are not that common so there probably isn't a lot published about how to make one.

Any device that operates from the power mains will likely require some type of safety certification, depending upon the country where you want to sell it.

 

[jiripolivka]

Wireless power transmission has developed into many funny forms recently.
Many years ago, an "open" AC transformer was used in toothbrush chargers and elsewhere. Such devices operate at 50/60 Hz and represent two coaxial coils to transfer ~1W over 1...2 cm distance, with some 20% efficiency.
Using a higher frequency, the distance may be extended but most of the RF power is radiated around, causing a quite poor efficiency. To avoid legal problems, "industrial" frequencies are used which do not require a license. 6.75 MHz, 13.5 and 27 MHz are close, also 910 MHz can be used, and 2.45 GHz where microwave ovens operate.
All such devices do transmit some power "at any cost", and mostly cause a lot of interference.
At the University of Michigan, a genius "discovered" the pair of resonant circuits to transmit with a "high efficiency". In fact such band-pass filter circuit was patented in ~1910 and was used ever since in most radio receivers as an IF filter.
Now the UMich genius blew the size up to ~0.5 meter of coil diameter, and using to such giant coils, he demonstrated RF power transmission of ~40 W over almost one meter... The device was demonstrated at shows to people never educated in RF basics. At 6.75 MHz, it met the "industrial no-licence operation" but radiated a lot of interference power far around.

More similar geniuses are working on more annoying stuff. Be ready for more nonsense and more interference!

 

[tpetar]

Yes there is regulations for this, and all depends from country to country.

Also check patents owners, if you plan massive production.

 

[mtwieg]

There are some emerging standards developing for wireless power:
https://www.wirelesspowerconsortium.com/developers/specification.html

I'm not sure how critical it is to adhere to these specifications though. Texas instruments have released a series of controller ICs which conform to these standards though.