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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?

Marcus Müller
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Quarterblad
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1 Answers1

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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.

Ale..chenski
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  • 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. – Quarterblad Jun 06 '21 at 09:05
  • @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."* – Ale..chenski Jun 08 '21 at 03:19