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LM2577: current limiter

Discussion in 'Electronic Design' started by Marco Trapanese, Sep 26, 2010.

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  1. Hi,

    I have a working board with a DC-DC step up with a LM2577-ADJ. Some more
    info:

    - input voltage: 12V
    - output voltage: 13V-19V
    - output current: up to 2A

    The output voltage is selected by a digital potentiometer inserter in
    the feedback voltage divider.

    I want to add a current limiter in order to lower the output voltage if
    the output current grow over 2A.

    What's the best way to achieve this?

    I can change the IC with another but I need a TO220 package and the same
    configuration. In other words, it should be nice a similar DC-DC with
    the Isense input pin.

    May you suggest something?

    Thanks!
    Marco
     
  2. Hammy

    Hammy Guest

    http://www.onsemi.com/pub_link/Collateral/MC34167-D.PDF
     
  3. Hammy

    Hammy Guest

    Nope sorry just had a quick look.

    You can try Murata to see if they have a small module that can fit your
    exsisting footprint and specs like these.

    http://canada.newark.com/murata-power-solutions/7803sr-c/ic-step-down-
    regulator-sip-3/dp/87K6144

    If it is just a few you can make your own like the one above useing one
    of the numerous boost controllers out there that has built in current
    limiting.

    Another simple hystertic controller

    http://www.onsemi.com/pub_link/Collateral/MC34163-D.PDF
    or
    http://www.onsemi.com/pub_link/Collateral/NCP3163-D.PDF
     
  4. Hammy

    Hammy Guest

    m:
    Good idea.
     
  5. Joerg

    Joerg Guest


    There's high-side current monitor chips that can do that almost directly
    (tie into the FB node as Neddie suggested). Some can have the sense
    resistor float dozens of volts above ground. I have done stuff like that
    many times, where 3-4 things tied into the FB node. Voltage, current,
    temperature, dance contest results, and whatnot.
     
  6. Il 28/09/2010 13:26, neddie ha scritto:

    Yes, I will do that if I don't find a suitable device. The problem is
    the space... I don't have much on the board.

    Marco
     
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