TPS65994AD: Motherboard with TPS65994AD Connected to Type-C Display - No Output After Hot Plug

Huang Jack

Part Number: TPS65994AD
Other Parts Discussed in Thread: TPS65994,

Tool/software:

I am working on a mature ADL-P project using the TPS65994 as the PD controller. The Type-C port is configured in ONLY SINK and DFP modes. It connects to a daughterboard (acting as UFP and Source device), which hosts the display. The display signal is processed by the daughterboard’s PD controller before being transmitted to the motherboard. Currently, I am encountering an issue: during hot-plugging, the UFP device detects the HPD change, but the system does not respond. After unplugging the screen, the display parameters still remain in the system. When the screen is plugged back in, there is no output (the display parameters persist). The log is shown in the figure below.

Any suggestions for debugging this issue would be greatly appreciated!

4 days ago

0 Tommy Lin 4 days ago

TI__Mastermind 31400 points

Hi,

Is the log collected between the daughterboard and the Type-C connector on the motherboard?

Regards

0 Huang Jack 3 days ago in reply to Tommy Lin

Prodigy 70 points

Hi,

Yes.

Thanks!

0 Tommy Lin 3 days ago in reply to Huang Jack

TI__Mastermind 31400 points

Hi,

Then I think the issue here is the daughterboard not transmitting the the correct HPD status from the monitor to the Type-C/PD controller on the mother board.

You can check this by collecting a PD log between the daughterboard and the monitor to crosscheck.

Regards

0 Huang Jack 2 days ago in reply to Tommy Lin

Prodigy 70 points

Hi,

From the diagram, it can be seen that the UFP daughter card detected an HPD event and sent a VDM to the TPS65994AD.

Thanks!

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TPS65994AD: Motherboard with TPS65994AD Connected to Type-C Display - No Output After Hot Plug