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TUSB2046B: TUSB2046B connections

albgarc2014
Genius 3480 points
Part Number: TUSB2046B

Hi TI!

I am designing a system that can connect N devices via USB. Each device has an MCU that has a USB interface (MSP432) and is powered by an external power supply independent of USB.

I show the connection diagram of 4 devices in an attached image.

1-) The diagram presents a possible topology for the TUSB2046B? Can several TUSB2046B be connected consecutively (as the diagram)?

I also attach my wiring diagram for the TUSB2046B.

2-) Is the schematic correct?

Note: since the power supply of each device is external I do not use current verification so:
OVRCURs on high pull up
PWRON unconnected
I use 6MHz crystal
BUSPWR to GND

Thanks very much!

  • +1
    TI__Guru**** 162206 points

    Hi,

    Max five hub can be supported, so I do not see an issue of cascading four TUSB2046B.

    For the schematic, 

    1. You would need a 1.5k pullup to 3.3V on DP0

    2. You would need 15k pulldown on DP/DM[1:4]

    3. Both bus-powered and self-powered hubs require overcurrent protection for all downstream ports. The two types of protection are individual-port management (individual-port basis) or ganged-port management (multiple-port basis). Are you implementing the overcurrent protection?

    Please see section 9.2.2 Detailed Design Procedure in the TUSB2046B datasheet for a detailed implementation example.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Genius 3480 points

    Hello David!

    Thank you very much for your response!


    I'm just not clear about the overcurrent protection. In my case each downstream port will be self powered externally and no 5V is transmitted on the USB (note that it is not a standard USB). I only need each downstream port DP/DM and GND (5V is not required).

    So if I don't need to supply 5V to the downstream ports, can I disconnect the PWRON1...4 pins and put pull ups on OVECUR1...4 (so I simulate that there is no overcurrent)?
    Is this idea possible?

    Thanks very much!

    Best Regards

  • +1 in reply to albgarc2014
    TI__Guru**** 162206 points

    Hi,

    If you are not using the power management for the downstream ports, then you can pull OVERCUR pins high to 3.3V and leave PWRON unconnected.

    Thanks

    David