WLC99Rx Stuck in DC Mode

unspun_matt · ‎2024-06-12

I'm getting a STEVAL-WLC99RX and STEVAL-WBCTX70 configured for some testing and put the WLC99RX in DC mode (5V ono Vout). I cannot figure out how to get it back into Rx mode.

It feels a little bit like a chicken and egg situation. I need to be in DC mode to connect and configure right now, but I can't be in DC mode if I want to use WPT.

Help me @willzhou

Cheers,

matt

willzhou · ‎2024-06-13

Hi

Please follow this link and find wlc99 AN.

Wireless Charging solution Wiki - STMicroelectronics Community

DC connect vout is use for download fw.

When WLC99 is in rx mode, you need to cut off power 5V on VOUT.

add python example code for wlc99

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unspun_matt · ‎2024-06-13

Thanks for the reply. I've browsed through the linked files and went over the README in the repo, but I didn't find the info I needed.
I removed 5V from Vout and placed the Rx coil on top of a powered and ready STEVAL-WBCTX70, but the WLC99RX isn't powering on. Was the WLC99RX supposed to automatically switch back to RX-mode when I removed 5V from Vout?

The tx and rx coils are right on top of each other and concentric, so it shouldn't be any kind of coupling issue. The WBCTX70 shows in software that the rx coil is being detected but WPT isn't happening.

willzhou · ‎2024-06-27

Sorry for miss your message.

"Was the WLC99RX supposed to automatically switch back to RX-mode when I removed 5V from Vout?"

Answer: Yes, it is automatically.

About "WLC99RX isn't powering on" what is the wlc99 vout set, is it 5V?

Can you capture some picture or log with GUI tool, so i can get more information.

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unspun_matt · ‎2024-07-18

Thanks! I figured out that the issue was related to Vin on the STEVAL-WBC70TX. I was applying 20VDC to the barrel jack and didn't realize this would cause an error since it is under the Vin max (24VDC). After lowering the barrel jack Vin to 12VDC (and removing 5V from the Vout of the WLC99RX) the problem resolved itself. I was then able to power on the system with 12VDC, move into STSC mode, and increase Vin to 20VDC.

I noticed that the throughput and efficiency of the system was much worse when connecting a 20VDC/4A power supply directly to the barrel jack and operating in STSC mode than when using a USB-C PD source.

simonh · ‎2024-09-16

How have you switched to STSC Mode? I have a WLC98RX Board here, but I cannot find any settings which allows that.

unspun_matt · ‎2024-09-19

I found the instructions in section 7.6 (page 78) of the user manual; attached.