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TUSB2046B: Interface between TUSB2046 and TPS2044

Part Number: TUSB2046B
Other Parts Discussed in Thread: TPS2044,

Regarding functionality of PWRON and OVRCUR discretes...

If connected the same way as TUSB 2046 datasheet Figure 11, would the following statements be true:

(1) When the hub detects a fault on a downstream port, the corresponding PWRON output pin is set to a logic high.
(2) Upon detecting an overcurrent or overtemperature condition, TPS2044 sets the corresponding OVRCUR pin to a logic low.
(3) TUSB2046 then sets the corresponding PWRON output pin to non-active high.

  • Hi,

    (1) When the hub detects a fault on a downstream port, the corresponding PWRON output pin is set to a logic high.

    • Correct

    (2) Upon detecting an overcurrent or overtemperature condition, TPS2044 sets the corresponding OVRCUR pin to a logic low.

    • The OCx open-drain output is asserted (active low) when an overcurrent or overtemperature condition is encountered. The output will remain asserted until the overcurrent or overtemperature condition is removed.

    (3) TUSB2046 then sets the corresponding PWRON output pin to non-active high.

    • No, you have to make sure the overcurrent or overtemperature condition is removed first. The USB host then controls the port power of TUSB2046B using the SET PORT FEATURE (PORT POWER) and CLEAR PORT FEATURE (PORT POWER) commands, these commands cause the TUSB2046B to assert or dessert the PWRONz outputs. 

    Thanks

    David

  • Interesting that the TUSB2046 does not automatically deassert PWRONx output (non-active high) if corresponding OVRCURx input is asserted (active low).

    Thank you for your response.

  • Hi,

     if corresponding OVRCURx input is asserted (active low). then this means the overcurrent or overtemperature condition still exists. You have to remove or clear the overcurrent or overtemperature condition first. The USB host will then have to re-enable the PWRON output (active low) as per the USB spec.

    Thanks

    David