I'm currently designing a bus-powered usb 3.1 hub. It will use a USB-C for UFP and 3 USB-A downstream. The hub will only be acting as a sink.
As of my understanding, since it may be connected to USB 1 (low speed), I need to limit the possible current drain to 100mA before negotiations, and only after negotiations, set the maximum current drain that can be provided upstream?
I have been looking at two reference designs from TI that specifically states "USB 3.0 compliant hub". Is that really correct?
Neither of these reference designs have implemented current limiting upstream, only downstream.
I have been looking for IC's that specifically manage current limiting upstream, but so far I have only found down-stream limiting.
Do I need to limit the hub's power drain?
Do anyone know of a chips that manage this or reference design which have implemented power limiting upstream based on the current negotiation?