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TLV62090: Can Softstart (SS) be externally shorted to force another softstart cycle?

George Peterson
Expert 3170 points
Part Number: TLV62090

Dear Team,

My customer would like to detect a specific load event with external circuitry and force another softstart cycle.   Can we short the softstart (SS) capacitor externally to force a new softstart?

I originally suggested toggling the Enable pin but they would prefer to use the softstart input.

Thank You,

George

  • 0
    TI__Guru*** 145650 points
    You can always assign this thread to me and add the customer details in the toolkit at the top.

    Yes, this should be possible. If I knew some more application details, I could comment more.

    Note that this IC has a current limit foldback and hiccup current limit, so you cannot draw the full current at the lowest output voltages, while Vout is ramping up.
  • 0 in reply to Chris Glaser
    Prodigy 30 points

    I've been told that the SS cap will be discharged upon the EN pin going low.  I'm going to need a long (> 1/2 sec) soft start thus a big soft start cap.  Is there any specification (even typical) for the discharge resistance (or current) to ground the soft start cap during this function?  I need to determine the minimum low going pulse width needed on the EN pin to assure a normal soft start upon the rising edge.

  • 0 in reply to Paul Delucia
    TI__Guru*** 145650 points
    Yes, the SS/TR pin is discharged when EN goes low.

    You could measure this discharge with a scope and calculate the RC time constant to confirm but the internal discharge resistor should be around 4k.