1
\$\begingroup\$

I am trying to desing extension board with USB 3.1 gen 1 Type C in DFP (host) role.

To support the flipping of the connector I chose PI5USB30213A. I planned to use default voltage and current configuration - 5V 0.9 A with no PD or 1.5 A etc. PI5USB30213A just muxing high speed lines and configure CC lines.

In the typical application circuit I saw that I need a "DFP mode charging circuit ". In TI's A primer on USB Type-C ® and USB Power Delivery Applications and Requirements I saw that I need a 5V VBUS FET to switch on 5V rail when some device is plugged.

PI5USB30213A has ID pin with description:

open drain output. Asserted low then CC pin detected device attachment when port is a Host, otherwise ID is hi-z.

Can I simply connect VBUS on main 5V from main board (and some capasitor around connector) or do I need a FET (can you advise some?) to commutate 5V to VBUS pins?

\$\endgroup\$

1 Answer 1

Reset to default
0
\$\begingroup\$

By Type-C specifications, a Type-C port should not supply any power until CC pins signal any connection, and power roles of connected partners are identified via Rp/Rd sense mechanism.

So yes, you do need a high-side power switch to turn VBUS on, which should be controlled by this "ID" pin. Almost any P-FET can do this job, but I would strongly advise to use a dedicated high-side switch (aka "power distribution switch) with enable=LOW, something like TPS2061.

\$\endgroup\$
2
  • \$\begingroup\$ Thanks for the answer. I looked at the specifications from USB, but I did not find the sequence that the VBUS up only after connecting the cable. Can you please indicate where you found this information. \$\endgroup\$
    – Quarterblad
    Jun 6, 2021 at 9:05
  • \$\begingroup\$ @Quarterblad, see section 4.2.2 of Type-C specifications, which says: "These pins are for USB cable bus power as defined by the USB specifications. This source is only present when a DFP-to-UFP connection across the CC channel is present – see Section 4.5.1.2.1. Refer to Section 4.4.2 for the functional requirements for VBUS." \$\endgroup\$
    – Ale..chenski
    Jun 8, 2021 at 3:19

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.