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Add current limiter on Bench PSU

HellasTechn

Apr 14, 2013
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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.
 
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davenn

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Sep 5, 2009
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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
 

HellasTechn

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Good day dave

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

Still recomendations and guidelines are welcomed
 

davenn

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

HellasTechn

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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
 

chopnhack

Apr 28, 2014
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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?
 

Arouse1973

Adam
Dec 18, 2013
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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?

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
 

davenn

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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

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
 

Arouse1973

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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

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
 

davenn

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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 ?
 

Arouse1973

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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 ?
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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