• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 32 subscribers
  • Views 573 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

USB Type-C question on initial current draw

Mark Pearson
Genius 12705 points

In a USB2.0 system that is implementing a Type-C connector - On the initial plug-in, what load current can the UFP consume?  Is it the 100mA from the USB2.0 spec (before enumeration) or is it something else?

Thanks - Mark

  • 0
    TI__Expert 6280 points
    Yes that is correct. Once configured (enumerated) it can then draw up to 500mA. However if a PD contract is negotiated that will take precedence. UFPs will have to limit the inrush current when initially passing power into the system before a PD contract is established.

    Jacob
  • 0 in reply to Jacob Ontiveros
    TI__Genius 12705 points
    OK - good to verify that.
    I'm dealing with a Non-PD design. So, If I can guarantee Type-C at both ends of the cable (Still USB2.0 data connection), how does one get to the 15W level promised by the Type-C standard? From what I can see - it will be entirely dependent on the Host, being a true Type-C end point that can negotiate levels higher than 500mA.
    Correct?
    Thnx!
  • 0 in reply to Mark Pearson
    TI__Expert 6280 points
    Type-C uses the channel configuration (CC) to detect the cable orientation and to determine the Type-C current advertisement. There are 3 levels; Default Current (500mA USB2 & 900mA USB3), 1.5A, and 3A. As a UFP you have to be able to handle the use case when you are connected to a legacy port with a Type-A to Type-C cable where the DFP is only capable of providing 500mA/900mA and VBUS is always hot. In its simplest implementation a comparator can be used to detect a 3A advertisement.

    Jacob