USB 3.2 Hub IC (standalone feature)

Hi Benjamin,

The TUSB8042A supports USB 3.2 Gen 1x1 operation (5 Gbps).  The hub only implements power control outputs, it does not have integrated power switches so the 5V would have to be routed outside of the hub IC.  Most USB to UART / RS232 bridge chips like the TUSB3410 will only convert to USB FS (12Mbps).  TI does not have any device that converts from USB 3.0 to UART / RS232.

Regards,

JMMN

Hey JMMN,

thanks for your reply. I think the biggest problem will be to find a bridge IC that converts to USB 3.2 and therefor supports 0.9A@5V, right?

I guess TI also doesn't have a chip that incorporates the power switch? 

kind regards,

Benjamin

Hi Benjamin,

I don't know of any USB hubs that incorporate the power switch.  If this is a closed system, the power consumption on the downstream ports won't be regulated by USB protocol and the bridge chips can use as much or as little power as needed.

Regards,

JMMN

Hey JMMN,

so this would mean I could also use an USB 2.0 bridge chip? Becasue the only reason for an USB 3.2 bridge chip would be the higher usable power for enumerated devices (0.9A). I did not know that USB would allow the VBUS to be not monitored. But it makes sense as there exist tons of devices that have their own power supply adapter.

kind regards,

Benjamin

Hi Benjamin,

Yes, power consumption is only defined by USB specification when devices are bus powered to prevent drawing too much current from an upstream port.  USB 2.0 bridge chips would likely work for your application as described.

Regards,

JMMN

Hey JMMN,

thanks for the clarification.Does there exist an IC that would grand me powering the USB FS bridge ICs with my requested 0.9A@5V from VBus? For example I would attach the IC to an USB-C Port and could then connect my four USB FS bridge ICs. It would have some great advantages using VBus to power the connected devices and not having to route a separate power path.

kind regards,

Benjamin

Hi Benjamin,

So you need to power a hub and 4 FS bridge ICs from a single port?   For that you would need a bus powered hub and by spec, a USB 2.0 bus powered hub could limit the power on its downstream ports to 100 mA per port.  How much power do you need for the application total?  

Regards,

JMMN

Hey JMMN,

that's exactly the problem. The four devices that communicate via serial (UART and RS232) need power up to 4W each. That's why a normal USB 2.0 Hub is not sufficient as it would only supply maximum of 500mA on each port. In addition to this I would need data and power isolation.

So my ideal circuit would do the following: Each of my 4 devices would have its own USB 3.x to serial bridge chip that could sink 0.9A@5V (isolated data and power).
As you already mentioned there does not exist a USB 3.x to serial bridge chip so I would have to go for an USB 2.0 solution (mostly FTDI), but with these I cannot draw enough current to supply the devices. I would have to supply the power externally and then it would be perfect if it would work over an USB 3.x Host or Hub, possible USB Type-C port. So in total I sink 4x 4W and distribute it with separate isoltaion to every device.

Hey JMMN,

ok. Thanks for the suggestion.
For my understanding: If I would like to draw 15W from an USB type-C Port I would need an IC that would do the correct device enumeration for me and that would support USB type-C, correct? So for example some like the STUSB4500L from STM. Do you have similar products?

kind regards,

Benjamin

Hi Benjamin,

We have similar Type-C controllers like the TUSB320, but your application would require that the Type-C port on the host is able to support the 3A @ 5V mode and not all do that.

Regards,

JMMN

Hey JMMN,

thanks for your answer and help. I have no all information I need.

kind regards,

Benjamin