STWLC38 FCC test settings

[Ryoma]

Hello expert,

We are developing a product using STWLC38 and are currently trying to obtain FCC certification.
In order to perform the test, the following is required by the testing agency.

・To output a continuously ASK modulated signal. (We only use BPP)
・To be able to perform the test on the receiver alone without the transmitter.

Is it possible to fulfill those requirements?
Also, if you have obtained FCC certification for STWLC38, how did you do it?

I don't understand if there are settings that continuously output ASK modulated signal.
Also, I think that STWLC38 cannot operate without a power transmitter
because it has AC input pins but no dedicated power pin.
I'd like to ask for your advice.

Regards,
Ryoma

[Didier HERROUIN]

Hello,

The FCC certification should be passed with a final product, it can not be passed by the STWLC38 alone.
What do you mean by "output a continuously ASK modulated signal" ? Indeed, sending a true continuous signal would violate the timings specified in the Qi standard.

Concerning the standalone mode, it is possible : you just have to supply a 5V on Vout signal, and the chipset will be awaken. This mode is already used (and mandatory) to program the chipset : indeed, you are not allowed to program the chipset (loading patch and configuration files) with the chipset supplied by a wireless charger (you must provide the 5V as explained).

[Ryoma]

Hi Didier, 

Thank you for your quick response.

As a premise, we don't aim to obtain the Qi standard. 
In order to perform FCC testing, the testing agency requires that
the STWLC38 outputs an ASK modulated signal continuously. 
Perhaps to measure signal strength.
However, the test must be performed without power supply from the transmitter.

I have used standalone mode when writing patch and configuration files. 
At that time, I supplied 5V to the Vout pin.

Is there a setting for continuous output of ASK modulated signals in standalone mode?

Regards,
Ryoma

[Didier HERROUIN · Accepted solution]

Hello,

Even if you do not look for the Qi certification, the STWLC38 is based on the Qi standard, and the ASK modulation timing is specified in the standard. It is not supposed to be active continuously. Moreover, it must be enabled only during power transfer phases, not in standalone mode, so there is not such a command.

The only compromise could be to transfer some custom packets from the receiver to the transmitter: it will increase the ASK modulation occurrence (it will never be continuous), and it can be generated only between CEP (Control Error Packets), it means only with a charger.

Regards,
Didier

[Ryoma]

Hi Didier, 

I Apologize for the late reply. 

I understood that it is not possible to continuously output the ASK modulated signal during power transfer phases.
I'll discuss the measurement method again with the testing agency.

Thank you so much for your polite response to my request.

Regards,
Ryoma