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TPS2511 Current Limit

Bryan Audiffred
Prodigy 100 points
Other Parts Discussed in Thread: TPS2543, TPS2511

I have an application where I would like to provide at most 500mA of charge current to a USB device.  The TPS25511 device cannot be forced into offering only SDP mode with a 500mA limit.  There is an adjustable current limit.  It would seem the current limit should simply be set to match the designer's intention of a 5W or 10W DCP charger. 

Is it permissible to supply less than the 1A of a 5W DCP port using the current limiting feature?  This places burdens on attached devices to monitor voltage drop and throttle their current.  I'm not familiar with USB specifications, but I'd be surprised if they behaved this way. 

  • 0
    TI__Mastermind 42795 points

    I apologize for the delayed response.

    Is it permissible to supply less than the 1A of a 5W DCP port using the current limiting feature?  No, this is not recommended because while some devices are smart enough, many will not be. I'd suggest you look at TPS2543 which can handle forced SDP.

  • 0 in reply to Eric Wright
    TI__Intellectual 1010 points

    Hello Eric.

     

    Could you suggest the current limit setting range under DCP divider 2 mode?

    Device could not deliver the current on the bench test when we set the current limit below 1.2A under DCP divider2 mode.

    And please let me know if you have TPS2511 device charging test report. (TPS2543 presentation file has test report (on the ESP) )

  • 0 in reply to j_yamamoto1
    TI__Intellectual 2795 points

    (1) DCP divider 2 mode is Apple 10.5w mode (D+=2.7V/D-=2.0V) and maximum charging current is 2.1A, so if want to support 2.1A,  the minimum current limit must exceed 2.1A and you can refer to TPS2543 "Current-Limit Setting" section to calculate the resistor.

    (2) I am not very clear your question, you mean that device can't charge when set the current limit below 1.2A, correct? Whic part in your test (TPS2543 or TPS2511)?

    (3) You mena the device compatability list? Please send eamil to me.

  • 0 in reply to Milo Zhu
    TI__Intellectual 1010 points

    Hello

    Please see my comments below>>

    (1) DCP divider 2 mode is Apple 10.5w mode (D+=2.7V/D-=2.0V) and maximum charging current is 2.1A, so if want to support 2.1A,  the minimum current limit must exceed 2.1A and you can refer to TPS2543 "Current-Limit Setting" section to calculate the resistor.

    >>Customer confirmed it that TPS2511 can deliver the output current with 1.6A limit setting to iPad.

     

    (2) I am not very clear your question, you mean that device can't charge when set the current limit below 1.2A, correct?

        >>Yes. correct.

    Whic part in your test (TPS2543 or TPS2511)?

      >>TPS2511.

     

    (3) You mena the device compatability list? Please send eamil to me

      >>OK. I will sent it to you on internal e-mail.