NFC dynamic tag & Qi wireless charging

[ASada.2]

Hi,

I am working on a project and trying to resolve a doubt I have before starting building the prototype, I appreciate if anyone could assist me with my question.

The project is based on NFC dynamic tags and wireless charging.

There are 2x devices in this simplified version of the project, let's call them Base Station and Target.

The Base Station talks to the Target device via NFC. The target device has 2x modes slow charge and fast charge modes.

The slow charge mode is via NFC wireless charing and the fast charge mode is via Qi wireless charging.

My question is: can NFC data communication co-exist with Qi wireless charging ?

Meaning could the device transfer data back and forth when the Qi wireless charging is ON ?

Would not Qi wireless charging overload NFC dynamic tag and break it ?

Any help would be highly appreciated.

Thanks

[Ulysses HERNIOSUS]

Hi ASada.2,

not really easy to answer your question.

Onging Qi power transfer will influence/degrade the NFC communication. Depending on matching, detuning effect and and quality of dynamic tag and reader NFC communication should still be possible albeit at possibly reduced range.

In general the PICC->PCD link with its load modulation is more susceptible to noise than the the PCD->PICC link. Here I advise on reader side to more look into ST25R3916(B) family as opposed to ST25R3911 reader family.

I think you need to do your own experiments and for sure own testing and fine-tuning to get such a system operating well.

Best Regards, Ulysses

[ArnaudR · Accepted solution]

If not already done, have a look at AN5364 How to protect ST25 tags from wireless power charging. It will ensure robustness of your design. And since the serial capacitance modify the communication profile, it should be added at the beginning of experiments.