[STWLC38] Operating Frequency and ASK modulation cycle

[Ryoma]

Hello,

I'm developing a Qi compliant product (Not getting Qi.) using STWLC38JRM.
Please respond on Operating Frequency and ASK modulation cycle to get back to the testing agency.

[Operating Frequency]
Qi standard defines the operating frequency from 110 kHz to 205 kHz.
Is it possible for STWLC38 to set (limit) operating frequency?
Or does it depend on the settings of the transmitter (e.g. STWBC86)?

The CFG file is provided by the customer, so I don't know the detailed settings. 
However, using "STSW-WPSTUDIO V2.2.5",
I have confirmed that "OP FREQ" shows approximately 139 kHz when charging in BPP.

[ASK modulation cycle]
I believe STWLC38 sends an ASK modulated signal towards the transmitter.
It seems that the signal is transmitted from STWLC38 in the digital ping phase,
but how often is it transmitted during charging in BPP?
Isn't it sent at fixed intervals during charging?
I understand that each communication bit of the signal is synchronized
with the cycle of STWLC38's internal 2 kHz clock.

Regards,
Ryoma

[Ryoma]

Hello, 

Could you please answer the above question?
I contacted "Online Support Case", but they told me to ask on the forum.

Regards, 
Ryoma

[Didier HERROUIN]

Dear Ryoma,

The operating frequency will be managed by the Transmitter: it will decrease it when the transmitted power must be increased, and increase it when the transmitted power is too high.

The power loop is monitored by the Rx: every 200ms, the Rx will send a Control Error Packet to the Tx in order to ask less or more power. This CEP is ASK modulated at 2kHz. 
During initial digital ping, the Rx must also send some information back to the Tx (using the same ASK modulation) so that the Tx can start the power transfer.

Let me know if you have other questions.

 

[Ryoma]

Dear Didier, 

Thank you for your reply.
For now, the examination is proceeding.
If I have any problems/difficulties, I might have to contact you again. 

Regards, 
Ryoma