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TUSB4041

Stanley Miller
Prodigy 10 points
Other Parts Discussed in Thread: TUSB2077A

Can Chip connect correctly to USB Port without EPROM or any other program jumper similar to TUSB2077A?

 

  • 0
    TI__Guru* 76130 points
    Hello,
    I don't fully understand your question, but if you are asking if the TUSB4041 can work without EEPROM, the answer is yes, it is fully functional without eeprom.
    Depending on your implementation and whether or not you require USB-IF compliance certification you may need an external eeprom or to perform some configuration via SMBUS.
    Regards
  • 0 in reply to Elias Villegas M.
    Prodigy 30 points
    We are using the TUSB4041 without an EEPROM. The 3.3V and 1.1V currents look great (26 mA total) until I plug in the upstream USB. At that point the 3.3V and 1.1V pull about 300mA of combined current. Any idea what to look for?
  • 0 in reply to Tim Hoover
    TI__Expert 7395 points
    Hello Tim,

    Can you provide your schematic to review it? I am particularly interested in reviewing how you are configuring the SMBUSz terminal on the device.
    When the device is on un-configured state it can draw over 300mA.
    Can you please also describe how is the device being used when this scenario occurs? I mean, is the USB hub properly enumerated on the system? Do you have any devices connected to the downstream ports? How many? at what speed?, etc.

    Regards,
    Jorge
  • 0 in reply to Tim Hoover
    Prodigy 30 points
    Thanks for responding Jorge. This high current only occurs when I plug in the upstream USB from the PC. We are using this hub in high speed mode upstream and downstream on two downstream ports (3 & 4). Downstream ports 1 & 2 are left open but we did add a pad on the pcb to tie D+ and D- together and ground if needed. The data sheet did not specify how to terminate the unused ports. Any help would be great! Thanks, Tim
  • 0 in reply to Tim Hoover
    TI__Expert 7395 points

    Tim,

    If power switching and battery charging is not required on the downstream ports, you should leave the PWRCTLx terminals floating.

    PWRCTLx terminals are used as an output to control the presence of VBus on the DS ports; since PWRCTL_POL is low, the PWRCTLx terminals will go high upon upstream connection.

    Additional observations on your schematic:

    • Unused ports should be left floating.
    • I would recommend to add a pull-up resistor on all unused OVERCURx terminals to avoid false detection of overcurrent events.
    • If USB compliance logo is being pursued:
    • Any exposed ports (with USB connector) shall sense overcurrent events (Hence OVERCUR terminal should be used)
    • Ports 1 and 2 shall be configured as unused (through an external EEPROM or SMBus master)
    • If either port 3 or 4 has a permanently attached device (No USB connector), the port shall be configured as non-removable (through an external EEPROM or SMBus master)

    Regards,

    Jorge