TUSB4020BI: About Usage for USB PD

Hide-san

You can reference to this e2e thread for designing TUSB4020BI with a PD controller, https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1004278/tusb4020bi-usb_vbus-connection-for-usb-power-delivery-application.

Thanks

David

Hi David-san,

Thank you for the information.

I understand the points to check are as follows.

Could you please let us know if you have any concern?

-If VBUS=9V, I have to control USB_VBUS voltage is less than 1.155V(max of Recommended Operating Conditions).

-And, USB_VBUS voltage should be around 500 mV when power is on.

-Therefor, we can install USB_VBUS pin divider resistors different than recommended

Regards,

Hide

Hide-san

Is USB_VBUS always going to be 9V? To be on the safe side, I would let PD controller handle the VBUS and use PD controller GPIO to control the hub USB_VBUS pin.

Thanks

David

Hi David-san,

It becomes "VBUS=9V" only when the USB adapter is connected.

And, there is no USB PD on the same board as TUSB4020BI.

Therefore, I thought of the plan I reported in the previous thread.

Could you please let us know if you have any concern?

Regards,

Hide

Hide-san

When PD Capable devices are attached to each other, the DFPs and UFPs initially default to standard USB Default Operation. The DFP supplies vSafe5V and the UFP draws current in accordance with the rules defined by [USB 2.0], [USB 3.1], [USB Type-C 1.2] or [USBBC 1.2] specifications. After Power Delivery negotiation has taken place power can be supplied at higher, or lower, voltages and higher currents. So without a PD controller, how are you able to negotiate power from 5V to 9V?

Thanks

David

Hi David-san,

I apologize for confusing you.

I understand that USB PD flow.

Please refer to my [Image].

USB PD communication is between device①(UFP) and USB PD adapter(DFP).

(Negotiate power from 5V to 9V)

So, There is no USB PD controller on TUSB4020BI board.

(We can't implement your idea.)

Regards,

Hide