TPS65987D: USBPD Alt Mode with TUSB1064 entering alt mode with a DP to HDMI converter

Carlson Magina

Part Number: TPS65987D
Other Parts Discussed in Thread: TUSB1064, TUSB1064RNQEVM, TUSB564

Using the TPS65987D to negotiate USB PD Alt mode with a TUSB1064 to switch the signals i have been able to get alt mode with a Display port to Display port cable to a monitor. I have tried to use three different DP to HDMI converters and none of them will allow Display capabilities. i have verified that the HPD signal toggles, that the dp connector has 3.3v. I verified with a docking station that the converter works with the s20 device. I am not sure what else to check to solve this problem. I have attached the pd negotiation and a couple pictures of the schematic and the config of the pd controller.

Altmode_project.pjt altmode with converter.csv

over 3 years ago

0 Carlson Magina over 3 years ago

Prodigy 135 points

altmode with_converter.zip the tdc file from Total phase PD analyzer

0 Chuck Branch over 3 years ago in reply to Carlson Magina

TI__Mastermind 32841 points

Carlson,

Based on what you have described, I am going to send this ticket over to the TUSB1064 team. I specialize more on the power and PD side of things and based on your issue, this appears to be working correctly. The TPS65987D is entering the correct alternate mode and the mux is being set into the correct state.

Regards,

Chuck

0 David (ASIC) Liu over 3 years ago in reply to Chuck Branch

TI__Guru**** 177836 points

Carlson

Looking at the schematic, are you AC coupling the AUX bus and have 1M pullup on AUXP and 1M pulldown on AUXN? What is the common mode voltage if you measure the AUXP/N?

Thanks

David

0 Carlson Magina over 3 years ago in reply to David (ASIC) Liu

Prodigy 135 points

so there is no decoupling caps or pull up or pull downs. The common mode on both is 3.3v. Which makes sense since the DP to hdmi converter i am using pull ups to 3.3 with 2k. Then connects to a PTN3381D to do the level shift. I followed the TUSB1064 evm (TUSB1064RNQEVM) and all the pull ups are dnp and there are no ac coupling caps

0 David (ASIC) Liu over 3 years ago in reply to Carlson Magina

TI__Guru**** 177836 points

Carlson

Are you using a DP to HDMI passive adapter or DP to HDMI active protocol converter?

Thanks

David

0 Carlson Magina over 3 years ago in reply to David (ASIC) Liu

Prodigy 135 points

I believe its active because i am using this IC PTN3381D https://www.nxp.com/docs/en/data-sheet/PTN3381D.pdf

v/r

Carlson Magina

+1 David (ASIC) Liu over 3 years ago in reply to Carlson Magina

TI__Guru**** 177836 points

Carlson

The PTN3381D is a passive level shifter. For this particular design, you would need an active DP to HDMI protocol converter such as the MCDP2900, https://media.digikey.com/pdf/Data%20Sheets/MegaChips%20PDFs/MCDP2900_DS.pdf.

On the AUX question, since you are going from a Type-C connector to DP connector, assuming the source already populated with 100k pullup/pulldown with AC coupling capacitors and sink already populated with 1M pullup/pulldown with AC coupling capacitors, then there is no need to have pullup/pulldown or AC coupling capacitors on the TUSB564. But you need to make sure the AUXP and SBU2 common mode voltage is between 0 and 0.4V and AUXN and SBU1 common mode voltage is between 2.7 and 3.6V.

Thanks

David

0 Carlson Magina over 3 years ago in reply to David (ASIC) Liu

Prodigy 135 points

thanks for the heads up. wasn't aware that the phone did not support passive adaptors. the active adaptors worked perfectly.

v/r

Carlson Magina

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TPS65987D: USBPD Alt Mode with TUSB1064 entering alt mode with a DP to HDMI converter