Other Parts Discussed in Thread: TPS55288
Hello,
In our application we have in internal battery we would like to charge using USB-C PPS mode. We also have an option to supply power from this battery (or external power source) to a sink connected to our product. For this we have included a TPS55288 that can be used as a PPS power source.
When looking into the TRM there is only one bit that mentions PPS mode ([1] pg 54, bit 23).
Looking into the PD 3.0 [2] documentation we need to remain active in communication in order to keep PPS 'alive' ([2] 6.619.1).
After a first study of the documentation I seem to be missing information.
For example I don't see options to execute PD messages such as 'Get_PPS_Status' ([1] pg 169). Is there a way to do this using th MBWr command ([2] pg 158)
When operating as sink I can imagine a way to first write register 0x37 and then issue a ANeg command [1] pg 152). However we need the PPS to operate in voltage mode and 0x37 only contains current and power fields.
When operating as a source I can imagine we receive a interrupt event (new RDO) that we would need to handle by configuring the TPS55288 with the correct settings.
I expect the PD controller to monitor current and voltage settings and disconnect & when physical levels (current, voltage) are outside limits. However I can't find any way to set levels & timing.
Has anyone experience or more information on this use case?
Kind regards,
Mark
Reference documents
[1] SLVUBH2B
[2] USB Power Delivery Specification Revision 3.0, Version 2.0 + ECNs, 7 feb 2020
