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TPS65987D: Question to Current Peak protection

Sergey Velykokhatko
Prodigy 190 points
Part Number: TPS65987D
Other Parts Discussed in Thread: TPS65987

Hi all,

As I see in Application Customization Tool there are a possibility to activate the Peak Current value as one of: 100%, 130%, 150% or 200%. But is it possible to select the maximum peak duration? Or how it works? I found nothing for it in reference manual

Thanks,

Best Regards,

Sergey

  • 0
    TI__Mastermind 32751 points

    Sergey,

    The later revisions of firmware make this control unnecessary.  We have implemented a digital filter in our system control loop that better meets the Peak current requirements in the Type C standard.

    This control does not do anything in our current implementation and can be ignored.

    Regards,

    Chuck

  • 0 in reply to Chuck Branch
    Prodigy 190 points

    Hi Chunk,

    Thank you for answer. But with answer I have the following questions. May be I just describe what we have and you could estimate is it ok or not.

    In our device we are using TPS65987 with PDO1 configured for 5V and only as output. I configured maximum current for PDO1 for 1A with peak current of 100%.

    Our device supports such external like USB-Stick, USB-LAN etc. But now we got requirement to support the USB GSM-Modem. In datasheet of modem written "Rated Power consumption 5V/400mA" and also "Max peak current 1600mA in GSM mode". There are no information about duration of current peaks.

    And now I am trying to understand what is the working possibility for this case. Is it enough just to set the peak current to 150% in Application Customization Tool? Then the TPS65987 has for Maximum Current of 1A setting the real current protection between 1,140A...1,393A and for 150% Peak Current it protects at minimum 1,140*150% = 1,71A. Is it ok?

    Thanks,
    Best Regards,

    Sergey

  • 0 in reply to Sergey Velykokhatko
    TI__Mastermind 32751 points

    Sergey,

    While I do not have the datasheet for that device, I would assume that they are describing a maximum constant current of 1600mA when they have turned on their RF and modem for GSM.  That current draw sounds about right for me.

    If you want to support this device, then you will need to support a 5V/1.6A PDO.  I would actually suggest that you set it to at least 2A.

    Does your system power level support this amount of DC current output?

    Regrads,

    Chuck

  • 0 in reply to Chuck Branch
    Prodigy 190 points

    Hi Chunk,

    I asked the modem manufacturer about duration of current peaks and still do not have answer. Support of TI looks working much better :) I attach here the screenshot with important modem information for this case

    Yes, our HW able to give 2A at 5V, but I would like to leave it with 1A and set the 200% of peak current instead of actual 100%

    One question: What is the specified duration of current peaks of Type C implemented in TPS65987? I lost myself in specification

    I think when modem manufacturer answers onto my question, I could just compare current peak durations of PD-Controller and of Modem, and when they will be not ok, then I can just set 2A of current limit with 100% peak current as also you propose

    Thanks for Support,

    Best Regards,

    Sergey



  • +1 in reply to Sergey Velykokhatko
    TI__Mastermind 32751 points

    If I read their spec, I suspect that you need to support  1.6A in your PDO to work with this device.  I do not think what they are describing as Peak current is the same as peak current in typeC.

    Try setting your PDO to 2A and I think this issue will go away.