TPS25750: Role switching with PD power pass through

Brandon Lackey

Part Number: TPS25750
Other Parts Discussed in Thread: TPS25751, TUSB320

Tool/software:

I am trying to design a system that connects an iPad to a ADC/DAC through a USB-C Port. The iPad should power the 5V_Bus in this configuration.

I have a second USB-C port to attach an optional external power source. When attached, the iPad should negotiate with the Power Supply to charge at up to 20V@3A. The Power Supply should also power the 5V_Bus.

My current design is below. I think it is mostly correct, however, I am getting the impression that the TUSB is the wrong part for this application. I also wonder if this is over engineered.

6 months ago

0 Chris Sterzik 6 months ago

TI__Guru 64141 points

Hello,

Please be advised that the TPS25750 is not recommended. Please use the TPS25751.

Your microcontroller will need to update the PD controller to control when the role would support source verses sink operation.

I will refer you to the TUSB320 team.

Regards,
Chris

0 Brandon Lackey 6 months ago in reply to Chris Sterzik

Prodigy 60 points

Thanks, Chris. The TPS25750, where it's used currently, should not be role switching, it will always be a sink to the power supply. However, I was under the impression (falsely?), that the TUSB would communicate the power capabilities and role switching with the iPad. However, it appears to only detect the role, not drive it (I will confirm with the TUSB team). Do I need a second PD controller to communicate with the iPad?

0 Vishesh Pithadiya 5 months ago in reply to Brandon Lackey

TI__Mastermind 39555 points

Hi Brandon,

For any charging or supplying of voltage past 5V 3A you will need a PD controller on both sides of the USB-Cconnection. Yes you will need another PD controller for the iPad/tablet facing port as well.

0 Vishesh Pithadiya 5 months ago in reply to Vishesh Pithadiya

TI__Mastermind 39555 points

Hi,

I'm closing this thread due to inactivity.

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TPS25750: Role switching with PD power pass through