I'm pretty new to USB overall. I've done some small simple power designs, but nothing too involved. In spite of that, I'm being requested to put together a design and I'm struggling a bit with figuring out how to make everything work. I'm sure that there's a solution, but my overall lack of experience is hampering me. I'm not sure if I even know quite what to ask for!
The overall design is an add-on to a phone, basically. I can't give details, but I don't think that is needed. (At least I hope not.) The phone connects to a USB hub chip (I'm currently thinking the Microchip USB7002) and provides power to the device (this is relatively low - I haven't specced it all out, but something like 100-200mA at 5V at most.)
The hub is also doing some bridging between SPI and UART devices onto the USB talking to an app on the phone. However, I also need the hub device to be able to plug into a computer for data up/download over to the phone, while also charging the phone. Then if it's plugged into a dedicated charger it should have quick-charge capability.
Now onto what seems to be my problem. (I'm also going to try Microchip's forums, but I'm still waiting on admin approval of my account before I can do that.) I think because the chip only supports power delivery/battery charging on its downstream ports that I need to have one of them be the phone. But the computer will not be plugged in the majority of the time, so this would leave port 0 disconnected. I don't know if this is a valid use for the chip.
I also don't know if I'm missing some other hub chip out there that is better suited for this. I need a total of three USB-C connections (one for the phone, one for the computer/charger, and the third for future expansion port), as well as a SPI and a UART bridge, but if needed those can be on a dedicated chip.
Of course I don't expect anyone to do the design for me, but if anyone out there already has dealt with something similar and has any pointers to offer, I would love to hear them! I let them know upfront that I didn't have this experience, but I was the person available, so I ended up with the project. It's been quite a learning experience already, but I feel like I've hit a wall here, so I wanted to reach out and see if anyone can tell what I'm missing.
Thanks!