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Add current limiter on Bench PSU

Discussion in 'Power Electronics' started by HellasTechn, Apr 12, 2015.

  1. HellasTechn

    HellasTechn

    1,407
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    Apr 14, 2013
    Dear friends.

    I have a 2-30 Volts DC 10A bench power supply that has no current limiting capability.

    I would like to add that feature. What i have in mind is by use of a potentiometer to set the maximum current that a circuit can draw (not to kill current when limit is reached)

    A circuit for that would be nice but that would not help me learn now would it ?

    What i am looking for here is guidelines on how to do that and i am willing to dig into it.

    I can draw the diagram of my PSU.

    Thanks.
     
    Last edited: Apr 12, 2015
  2. davenn

    davenn Moderator

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    Sep 5, 2009
    hi Constantine

    I typed PSU current limiting circuit into google and got 100's of hits
    try the same and have a look through a few sites and circuits.
    If some interest you and appear to do what you want, give those links and
    any questions on anything not understood :)

    Dave
     
  3. HellasTechn

    HellasTechn

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    Apr 14, 2013
    Good day dave

    I already did that. i will get back with more.

    Still recomendations and guidelines are welcomed
     
  4. davenn

    davenn Moderator

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    There's just such a huge variation in ideas ;)
     
  5. HellasTechn

    HellasTechn

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    Apr 14, 2013
    Why cant i see them ? :)

    I found the lm317 adjustible current limiter but it is for 0-5 Amps.

    looks like they have nothing for 0-10 Amps
     
  6. chopnhack

    chopnhack

    1,571
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    Apr 28, 2014
    I am with you on this Konstantine!
    I too am looking for a way to add that to my build.
    I did add some PTC's at the end of the rails to act as absolute cutoffs to prevent shorts. I don't know if this is the best way of doing it or not.
    I think I will include an LED that comes on when overcurrent is reached. I did see other builds where once overcurrent was reached, the LED came on and no further increases in current occurred.

    10A is quite a lot, do you use that much capacity? What do you use it for?
     
  7. Arouse1973

    Arouse1973 Adam

    5,164
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    Dec 18, 2013
    Have a look at the LT3081 you can make a 3A adjustable PSU using two of them. The current might be a bit low though.
    Adam
     
  8. davenn

    davenn Moderator

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    Adam, that was a bit vague ... adj current or voltage ??

    both guys already have the adj voltage sorted out in their projects
    what they want is current limiting
     
  9. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Hi Dave
    They wanted adjustable current, which is why I said a 3A adjustable PSU. You can have adjustable voltage also if you want.
    Cheers
    Adam
     
  10. davenn

    davenn Moderator

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    Sep 5, 2009
    OK, they are only 1.5 A rated, a long way from the 10A Constantine is wanting ;)

    and it would be interesting to see how/if it could do adj V and adj A at the same time ?
     
  11. Arouse1973

    Arouse1973 Adam

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    Dec 18, 2013
    Hi Dave
    Yeah 1.5A each which is why I said use two. But I don't know if 3 Amps is enough, It should be enough for most general stuff. It's easy to make a adjustable voltage and current power supply with two of them. The datasheet has an example that can be modified.
    Adam
     
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