Hi, I took a look at the Expansion Card GitHub repo and made a little physical mockup of a 2-port USB-C adapter. I played around with dual USB-A and concluded it would be an incredibly tight squeeze, and even if I could jam them both in, I’d be very concerned about the spacing between the two ports. But, two USB-C ports seem to fit fine.
I noticed a another comment here where someone said that the silicon doesn’t exist to support such a device, but I’m not sure exactly why that is, or what the implied limitations are? For all intents and purposes, this would just be a regular 2-port USB hub, right? Unless I’m missing something important, which is totally possible!
Anyway, I’d probably go about implementing a hub like this using something along the lines of a Microchip USB5742 chip, which supports 1 upstream and 2 downstream ports at both USB 3 and USB 2 speeds, as well as PD (power delivery). It doesn’t even look like a separate microcontroller would be required, just a crystal and some passives. I’d bet there are similar USB hub ICs from other manufacturers too (eg. TI, etc.). But, before I actually start working on something like this, perhaps someone can give it a sanity check? Why wouldn’t this kind of solution work?
Here are some renders of my mockup:
- PCB is 0.8 mm thickness
- USB plug is Molex 1054440001
- USB ports are TE 2129691-1