STEVAL-WBC86TX and STEVAL-WLC38RX coil change

[David101]

Hello everyone,

I got the above mentioned Eval boards with the following adaptions to suit my application:

- Tx coil connected to STEVAL-WBC86TX: WE 760308101104 

- Rx coil  connected to STEVAL-WLC38RX: Custom PCB antenna with ~1.5 µH self-inductance, ~ 9 x 9 mm^2 size

- Rx Ctank: 1.57 µF --> leads to a resonance frequency of ~102 kHz for the receiver circuit

When I place the receiver coil in 2 mm distance to the transmit coil, I can see the ping by a repeating short light-up of D7 on the STEVAL-WLC38RX board. However, there is no power transfer and STSW-WPSTUDIO connected to the transmitter indicates a signal strength timeout as EPT reason. Here is my TX configuration:

Also, here is a screenshot of the AC1 & AC2 signal on the receiver coil that I can see when the transmitter sends a ping:

I assume that the coupling between my antennas is too bad for a sucessful communication and power transfer between the boards. Is there any measure I can take on the Tx side to improve the ping so that the receiver gets enough power for answering, such as increasing the Tx coil voltage? Do you have any other suggestions for making it work?

Thanks!

Best regards,

David

[willzhou]

Hi Sir

You have change RX coil from 8uh to 1.57 µF, so your RX Ctank should change to, or you can use 9V or 12V for STWBC86.