TUSB2077A which PWRON signal to use in ganged mode

Wamor

Other Parts Discussed in Thread: TUSB2077A, TPS2041

Hello,

I have a newly developed board with a TUSB2077A and a TPS2041 on it.

I had connected the Enable input of the TPS2041 to pin 36 (PWRON7) of the TUSB2077A but the downstream-power would not be switched on.

After connecting the Enable input to pin 23 (PWRON4) of the TUSB2077A everything works fine.

I measured the voltages of the PWRON-pins of the TUSB2077A and saw that the PWRON-pins 1 to 4 are low and pins 5 to 7 are high.

Which PWRON-pin shoudl I use when the USB-hub is configured in ganged-mode. I would expect all PWRON-pin behave the same.

Thank you already for your answers.

Regards,

Wamor

over 10 years ago

0 Joel Jimenez0 over 10 years ago

TI__Mastermind 18655 points

Hello Wamor,

Is OVRCUR#/ pin low?

Upon detecting any overcurrent conditions, the power-management device sets the corresponding OVRCUR/ terminal of the TUSB2077A to a logic low. If GANGED is low, all PWRON/ outputs switch together and if any OVRCUR/ is activated, all ports transition to the power-off state.

Could you post your schematics, I would like to review them?

Regards.

0 Wamor over 10 years ago in reply to Joel Jimenez0

Prodigy 60 points

Hello Joel,

Thank you for your response. The OVRCUR#/ pins are connected together and are all high.

Could you maybe send me your private email-address. I don't want to place my schematic on this public forum.

Could it be that the PWRON#/ pins 5 to 7 are not switched on because the hub is configured is bus-powered mode.

In bus-powered mode your are limited to 4 downstream-ports because of the limited bus-power (1x 100 mA for the HUB and 4x 100 mA for the downstream-ports which gives 500 mA in total).

Regards, Wamor

0 Joel Jimenez0 over 10 years ago in reply to Wamor

TI__Mastermind 18655 points

Hello Wamor,

Please send me an email to joel.jimenez@ti.com.

Regards.

0 Joel Jimenez0 over 10 years ago in reply to Wamor

TI__Mastermind 18655 points

Hello Wamor,

I have reviewed your schematics and as your hub is using bus-powered mode it cannot enable all its downstream ports. The TUSB2077A support up to four downstream ports , as shown in the figure below.

Regards.

0 Wamor over 10 years ago in reply to Joel Jimenez0

Prodigy 60 points

Hello Joel,

Sorry for my lat response but thank you for your answer.

I now understand why I could not use PWRON5 till PWRON7.

Regards,

Wamor

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TUSB2077A which PWRON signal to use in ganged mode