cancel
Showing results for 
Search instead for 
Did you mean: 

USB EZ-PD Type-C

Contributor II

Question is rather simple,

I notice for some USB-C designs, CC2 is simply tied to VCONN on the CCGx device (like this one here: https://www.cypress.com/documentation/reference-designs/ez-pd-ccg3-usb-type-c-displayport-cable-solu... ), but what if I am looking to have a USB-C to DP dongle with Power Delivery as well?  Can CC2 be tied to VCONN or is haiving both CC lines connected a requirement for PD?

EDIT: To clarify, The requirements of our design mean we have to have a receptacle on the UFP side, not a plug.  It's really more a USB-C monitor than just a dongle (hence the need for PD as well as USC-C to DP functionality).

Thanks!

0 Likes
Reply
1 Solution
Moderator
Moderator

Hi Kyle,

Thanks for the clarification. In that case, you can connect both the CC lines to CYPD and leave the VCONN pin floating. CYPD will put up Rd terminations on the lines and detect the orientation from the connected cable.

Best Regards,

Sananya

View solution in original post

0 Likes
Reply
6 Replies
Moderator
Moderator

Hello,

No, you only need connection on one of the CC lines for type-C implicit contract and thereafter explicit PD contract. In the reference designs you are looking at, we have a plug on the CCGx side so only one of the CC lines need to be connected while the other is fixed as VCONN. The receptacle is symmetric in terms of its pinout design and hence will be able to monitor both the CC lines and detect which CC line has the terminations. Please refer to the KBA for a more detailed explanation.

Best Regards,

Sananya

Contributor II

Hi Sananya,

Thanks so much for the reply, and for the KBA reference.

If I'm reading this right, for a a USB-C to DP dongle w/ PD we DO want both CC lines going to the receptacle, and the role of each line is determined by the CYPD upon connection and it treats them appropriately?

Does this mean for our device we would want to have VCONN on the CYPD device be left floating since we can't determine via hardware which pin will be carrying VCONN?

Thanks again for the help!

0 Likes
Reply
Moderator
Moderator

Hello,

If you want to design a Type-C to DP dongle, it should have a plug on its upstream port so in that case you can route only one CC line to CYPD because the controller on the receptacle side will take care of the orientation. So on our board, we will fix the other CC line to VCONN on CYPD. This CC termination model has to be followed even for a Type-C connection before entering PD since without the orientation detection, we cant determine decide which is the source and the sink.

Please refer to the reference design for Type-C to DP dongle, you can see CC1 on the plug has been connected to CC1 pin on CCG3 while CC2 is connected to VCONN.

Best Regards,

Sananya

0 Likes
Reply
Contributor II

Sananya,

The requirements of our design mean we have to have a receptacle on the UFP side, not a plug.  It's really more a USB-C monitor than just a dongle (hence the need for PD as well as USC-C to DP functionality).  So we won't know which line VCONN will be on.

My understanding was that when the CYPD is configured as a UFP, it will properly identify itself to the connected host as a power consumer via the connected CC lines.  My question then becomes what do I do with the CYPD VCONN pin on the UFP since I have no way of knowing which of the CC lines is VCONN from the host?

0 Likes
Reply
Moderator
Moderator

Hi Kyle,

Thanks for the clarification. In that case, you can connect both the CC lines to CYPD and leave the VCONN pin floating. CYPD will put up Rd terminations on the lines and detect the orientation from the connected cable.

Best Regards,

Sananya

View solution in original post

0 Likes
Reply
Contributor II

Sananya,

Thank You very much for the help!

0 Likes
Reply