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TUSB8041-Q1: USB_VBUS pin when Battery charging is not used

Intellectual 2165 points

Replies: 3

Views: 125

Part Number: TUSB8041-Q1

hello,

What is the purpose of the USB_VBUS pin? Is that needed when battery charging is needed only? if so how should the pin terminated when battery charging is not used?

If there is  local 5V regulator that supplies VBUS, and there is no upstream VBUS, then should this pin be connected to the local 5V regulator output?

ito 

  • Hi,

    If the upstream port is always connected, as in a system where TUSB8041-Q1 is on the same PCB as USB Host, USB_VBUS should always be high (Vh = 400 mV). This signal is critical as it tell TUSB8041-Q1 that a USB Host is present on the upstream port. If you do not have a 5V signal that is associated with the USB Host (no upstream Vbus) the recommended voltage divider can be sized to accommodate other voltages (3.3V, 1.8V, etc) and still present Vh = 400 mV when the source voltage is present. I recommend that this source voltage come from a configurable GPIO for added flexibility. 

    Best, 

    Malik

  • In reply to Malik Barton57:

    hello Malik,

    if i apply 1V signal to the USB_VBUS pin directly instead of apply 5V VBUS using resistor divider, will the device work properly? 

    Ito

  • In reply to Takuma Ito:

    Hi,

    As long as you change the values for the resistor divider is changed to ensure the high voltage seen by USB_VBUS is at least ~400mV then th device should work properly. 

    Best, 

    Malik

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