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TUSB2036 Hub Circuit Can't Get 5V Output for USB Connectors

Josiah Wei
Prodigy 10 points
Other Parts Discussed in Thread: TUSB2036

Hi All, 

I have a TUSB2036 Hub circuit, basically the requirements are:

1): 2 downstream ports need to work (prefer DP1/DM1 & DP2,/DM2),

2): For individual or gang mode, either is OK.

I have following measurement:

1): TUSB2036 Overcurrent protection pins (Pin 10, 14, 18) are always low.

2): TUSB2036 Pin 6 (Ganged or individual selection pin) tied to 3.3V

3): TUSB2036 Pin 26 (External EEPROM selection pin) tied to 3.3V

4): Downstream 3 are floating (TUSB2036 Pin 19, 20 are floating)

5): Power -on/-off control signal and overcurrent protection signal for downstream 3 are floating (TUSB2036 Pin 17, 18 are floating) 

Now the problem is:

1): Power-on/-off pin are always high. (TUSB2036 Pin 9, 13, 17), no 5V power output for 2 USB connectors

I attach the schematic below, does any one can help me to verify the correctness of the schematic?

Thank you very much!

Sincerely

Josiah

  • 0
    TI__Mastermind 18655 points
    Hello Yanzhi,

    The DP and DM signals of the unused port should be tied to ground with 15K resistors like the pull-downs used on the active ports.
    The OVRCUR/ input of the unused port can be left tied to the other OVRCUR/ inputs if the hub is configured as GANGED.
    If the hub is not configured as GANGED, OVRCUR/ input of the unused port should have a pull-up resistor. A value of 1.5K is sufficient.
    I would like to see a scope captures of the power-up sequence for RESET#, XTAL and Vcc for the device.

    Regards