STWLC38 not working

malikbilal345 · ‎2025-09-28

Hi!

We have designed a custom board using STWLC38 but its not working. We also have the Evaluation kit of STWLC38 and Im using the same coil to test my custom board.

Im getting roughly 0.6V at VRECT pins after nearly every second.

I aslo have attached my schematics. Please help me out with this.

Regards,

malikbilal345 · ‎2025-10-01

Thank you very much for your support!!!

View solution in original post

Didier HERROUIN · ‎2025-09-29

Hello,

If I well understand, the eval kit works with you use the 8µH coil and your board does not, using the same coil and the same charger.

Your STWLC38 is probably not programmed.

You can connect the GUI (using I2C link) and select "empty" instead of "Rx": the GUI should connect.
Then, in the "Programming" menu, you can select the patch and config files I have put in attached and press "Write" : you should be now able to connect the GUI in normal mode (selecting "Rx" and "WLC38").

Concerning the schematics, you can remove the part which is used for Tx mode (keeping the 4*100nF capacitors) as STWLC38 FW only allows Rx mode.

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Didier HERROUIN · ‎2025-09-29

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

Didier HERROUIN · ‎2025-09-29

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

malikbilal345 · ‎2025-09-29

Thank you very much for your kind effort and support.

I tried but unfortunately my chip is heating up alot, which concludes my chip has burnt and I don't have another at the moment.

Just being curious, is there anyway that we could use a new chip without programming and without a host microcontroller? So, we don't have to program all the chips in the mass production?

Didier HERROUIN · ‎2025-09-30

Hello,

Your schematics look correct, it may be an assembly issue then.

Concerning the MP step, all the chips must be programmed after assembly as they are shipped blanks. You can either use a MCU or an Automatic Test Equipment (besides the I2C link, a 5V must be supplied through Vout during programming).
Then, STWLC38 is a standalone product, no MCU is required.

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malikbilal345 · ‎2025-09-30

Maybe an assembly issue but board is expired.

Alright, so programming is must for once whether it's done through MCU or ATE. Is there any software library for MCU to program those Config and Patch files directly to STWLC38?

Didier HERROUIN · ‎2025-09-30

Yes, I can provide you drivers examples to ease the FW loading.

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malikbilal345 · ‎2025-09-30

That would be great.

Please provide me those drivers. I will test them with my dev kit.

Didier HERROUIN · ‎2025-10-01

Dear malikbilal345,
You will find attached the drivers examples.

As you may probably need additional help in the future, be aware that the support for mass market has been restricted, which explains why the documentation has been retrieved from the website.

Please contact your local components distributor, so that they will be able to guide you depending on your project.

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