We have an Android tablet (USB-C) that is connected to a USB 3.0 hub that has power delivery (PD). The hub is connected to the charger (USB-A) via the hub's PD port (USB-C). There are a few USB devices connected to the hub as well (USB pendrive, USB UART, etc). When the charger is on, the tablet and USB devices connected to the hub are powered from the hub. When the charger is off, the tablet supplies power to the hub and USB devices connected to it.
We would like a USB switch solution that can be triggered electrically (from an MCU) to emulate physical connection and disconnection of the hub from the tablet. Manual (human) physical disconnection and reconnection is not feasible.
We can add a small circuit that would send a signal to a USB switch to open and close if there is lack of communication (over USB UART) between the tablet and the circuit.
Our problem here is how to make the USB switch? We have tried using relays for all signals (make/break same time) but it wasn't reliable (PD is sometimes slow charge). We have tried just making/breaking Vbus but that wasn't reliable too.
Our questions are:
1) Do we use a 2:1 mux for the signals? Or are there multichannel SPST analogue switches that can do the work?
2) Apart from the SST/SSR DP/DM signals, are we correct to say that CC signals also need switching (i.e. 8 signals/4 signal pairs in total)?
3) What is suitable to switch Vbus while still maintaining fast charge (at least 15W)? Relay? MOSFETs? Specific TI ICs?
4) And is the order of connection important? Such as Vbus, then CCx thenother signals?
