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TPS2595: TPS2595 OVC Threshold vs Temperature Graph

Greg
Expert 2031 points
Part Number: TPS2595

Is there a mistake in Figure 11 of the documentation for the TPS2595?  Here is a screenshot of Figure 11:

The 10 mA curve is below 5.5V for all temperatures.  Here is a screenshot of the specs for VOVC and VCLAMP:

Should Figure 11 be titled "VCLAMP vs Temperature"?  The 10 mA curve is consistent with the typical clamp voltage, not the overvoltage clamp threshold.  I hope so anyway, because the graph suggests that a 5V +/- 5% supply would potentially be clamped by this eFuse device at higher currents.

Is VOVC independent of the load current?  If not, how much of a dependence is there?  I don't want this device to clamp on anything less than 5.5V at any load current level.

Thanks and regards,

Greg

  • 0
    TI__Guru 57737 points

    Hi Greg,

    I will get back to you early next week.

  • 0 in reply to Praveen GD
    Expert 2031 points

    Hi Praveen,

    Thank you for looking into this.  Have a great weekend!

    Regards,

    Greg

  • 0 in reply to Greg
    Expert 2031 points

    Hi Praveen,

    I want to clarify the 2nd question in my original post.  I don't care if the clamp voltage is less than 5.5V, I just don't want it to trip on anything less than 5.5V.

    Which brings up another question.  If the device trips at the VOVC threshold level, and at higher currents the output clamp voltage drops below the input voltage, when will the clamp be released?  When the input voltage drops below the VOVC voltage?  If so, how much hysteresis is there?  I searched the PDF for "hys" and the only matches involved UVLO and thermal shutdown.

    Regards,

    Greg

  • 0 in reply to Greg
    TI__Guru 57737 points

    Hi Greg,

    'Vovc' is the threshold at which Over voltage is detected. Once the over voltage is detected, TPS2595 clamps it to 'Vclamp'.

    As per design , there is no much variation for 'Vovc' with load current but 'Vclamp' is dependent on load current.  

    Yes, you are right Figure 11 can be named as 'Vclamp vs Temperature'.

    I will get back to you on your second question soon. 

  • 0 in reply to Praveen GD
    TI__Guru 57737 points

    Hi Greg,

    There is no hysteresis for Vovc threshold as per design. Practically you may see not more than a  few mV of threshold. 

  • 0 in reply to Praveen GD
    Expert 2031 points

    Hi Praveen,

    Thank you very much for answering all of my questions.  My apologies for not replying until now.  It all makes sense except for why hysteresis wasn't designed into the Vovc threshold.  It seems it could oscillate if the input voltage is at the Vovc threshold.  But the device shouldn't have an input hovering at that voltage, so it really doesn't matter a lot.  I'm happy with the way it operates and it should work out well.  The graphs in the datasheet should be renamed so that others don't get confused like I did.  Thank you again for your excellent help.

    Regards,

    Greg