STUSB4710 PD-Source Configuration Without Feedback

[AHammoud]

Hello,

I am using the STUSB4710 as a PD-Source in my project and have a few questions regarding its configuration. In my setup, I have not utilized the feedback configuration. Instead, I am connecting the PDO outputs of the STUSB4710 to a microcontroller. The microcontroller reads the status and subsequently adjusts the output of my buck-boost converter accordingly.

However, I am facing an issue where no negotiation occurs, and the output remains fixed at 5V. I would like to know if the STUSB4710 is capable of operating in such a configuration. Specifically, is it possible to achieve successful power delivery negotiations without using the feedback mechanism?

Thank you for your support!

[Didier HERROUIN]

Dear AHammoud,

By default, the STUSB4710 negotiates the contract/PDO with the SOURCE as a standalone, with no MCU. The PDOs are written in NVM, they should fit to the power supply capabilities. Then, the STUSB4710 will drive the GPIOs according to the contract which has been agreed with the SOURCE.
In your case, if it stays to 5V, it could mean that the power capabilities advertised by the SOURCE do not fit to the needs of the SINK, so no PD contract is established.