STSAFE-A110 Provisioning and STEVAL-WBC2TX50-Based Wireless Charger Prototype

[Kombo]

Hello, I am reaching out for assistance regarding a wireless charging prototype I have developed based on the STEVAL-WBC2TX50 wireless power transmitter evaluation board.

Here are the key details of my project:

Design and Assembly

- I followed the schematics, PCB layout, and reference designs provided in the UM3231 user manual.

-All components were sourced according to the BOM, including the STSAFE-A110 chip.

-I successfully assembled the PCB and flashed the firmware into the STWBC2-HP chip

Current Issue

• The wireless charger is not charging my Qi 1.3-compliant device (iPhone 11).

• When powered up and connected to the STSW-WBC2STUDIO GUI, the system remains in the WAIT State, with the PING_TIMEOUT event continuously logged.

• The Presence Detection values fluctuate, and the Bridge Voltage remains at 4.8 V, indicating that power transfer is not initiating.

1. Suspected Issue:

   • I suspect the issue may be related to the STSAFE-A110 chip, as it appears that the chip needs to be provisioned with a Qi certificate chain to work with commercial devices like the iPhone 11.

   • I am unsure if the STSAFE chip is the root cause or if there are other issues with my design or firmware configuration.

2. Request for Assistance:

   • Could you please guide me on how to provision the STSAFE-A110 chip with the necessary Qi certificate chain?

   • Are there additional steps or configurations required beyond assembling the PCB and flashing the firmware to make the system operational?

   • If the STSAFE chip is not the issue, could you provide guidance on troubleshooting the design or firmware?

I am happy to provide additional information, such as screenshots from the GUI or further details about my setup, to assist in diagnosing the issue.

Thank you for your support, and I look forward to your response.

Regards

Kombo

[Benjamin BARATTE]

Hi @Kombo ,

Thanks for your interest to ST Solution

Regarding the STSAFE-A110 solution for Qi 1.3 you need to have a custom personalization.

Even with test sample, they are not compatible for official Qi device. This is only for testing.

To be compatible with an official Qi device, you need to get WPC certification of your design and then we can help you to get the Qi certificate for your product.

But you can't build up a test device and try it with Official Qi device.

Best Regards,

Benjamin

[Kombo]

Dear Benjamin,

Thank you for your response and clarification regarding the Qi 1.3 authentication requirements for official Qi-certified devices.

Since I am currently developing a prototype device with wireless charging, I am not pursuing WPC certification at this stage, I would like to know if there is a way to use the STEVAL-WBC2TX50 or my custom design in developer mode that allows testing without full Qi authentication.

Specifically, I would like to understand:

• Can I bypass or disable the STSAFE-A110 authentication for testing purposes?
• Is there an alternative way to test wireless power transfer to mobile devices on my custom design?

I appreciate any guidance you can provide on how to proceed with testing in a development environment.

Regards

Kombo

[Kombo]

Hi Benjamini. 

Qi 1.3 will not work since authentication is required. However, I should still be able to charge official Qi 1.2 and older receivers/devices with this transmitter design. Since my device is not detecting a receiver, I am now looking into possible hardware issues.

When probing with an oscilloscope to detect the analog pings, I observed that the frequency is much lower than expected—65 kHz instead of the typical 100–300 kHz for Qi chargers. This suggests that something might be wrong with the power stage or the inverter circuit. I will investigate further to see if the H-Bridge is switching properly and whether the DC-DC boost converter is supplying the correct voltage