Building CT-VPD dongle with ST products

[VasylV]

Hi all.

Are there any guides on building the charge-through VPD device with the ST product? An illustration from the standard:

The goal is to maintain the smartphone's supply from the external PD charger while maintaining the connection with a USB 2.0 auxiliary device (specifically, the simple USB CDC device). The auxiliary device consumes <0.1 W.

[FBL]

Hi @VasylV 

TCPP02 and TCPP03 can manage up to 0.1W using Vconn. From HW point of view, that should be ok.

However, there are no guidelines as done with SINK / SOURCE / DRP cases with examples. VPD is not supported on current library.

[VasylV]

Hi, and thank you for the comment!

I've looked through the ST portfolio, and if I stop focusing on VPD mode, STM32G071C8U6 might be a good match.

If I understand correctly, an ST MCU with two PD blocks can cover such an application. One port will act as a pure sink, and the other will be a DRD DRP port. The sink will authorize the highest advertised PDO, subtract its consumption + consumption of the auxiliary circuit, and re-advertise a smaller PDO to the dual-role port.

After studying the quick guide for dual role port, I'm sure your software could handle such an operation (role swap + FRS) with a bit of aux vdd capacitance to cover FRS transient. But I am unsure if the MCU can handle such an operation here. Your comment on that is highly appreciated.

Regards.