Hello, I'm designing a medical product, aiming at IEC 61000-4-2 level 4 ESD protection, and I have a question on the CC lines.
My understanding is that these two lines could be used by my device to identify the power capabilities of the charger, and potentially use this information to configure a certain VBUS current limit level accordingly. I also think this is only the case for chargers with a USB-C output (including laptops, docking stations etc), since I don't see how a charger with a USB-A port (such as many phone chargers) could make use of these pins (I would be very happy if somebody could explain clarify this bit :) )
Regarding ESD protection, in order to reach the required level I (think) I need to add extra ESD protection to the CC lines, and maybe also account for the possibility of a faulty PD charger delivering 20V combined with a short to VBUS fault (20V on CC/data lines).
Right now I'm using the USBLC6-2 ESD protection circuit from ST https://www.st.com/resource/en/datasheet/usblc6-2.pdf as a means of protection for the VBUS and data lines, however this does not provide explicit protection for CC lines.
Given my understanding of the CC lines, I think they are not useful in my application (I estimate to never surpass 300mA of current at VBUS), hence I'm considering disconnecting the CC lines from the PMIC, and simply adding two discrete pulldown resistors (for which I would not add ESD protection).
Is there any other use of the CC pins, maybe internal to the PMIC, that could create some problems if I proceed forward with this strategy?
Thanks for the feedback!
