Can't find negative regulator for bipolar supply

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riggler

Well-known member
Joined
Jan 24, 2006
Messages
1,076
Location
Pennsylvania, USA
Hi everyone,

I am building a +-25V supply for a project. Current draw will be about 2.2A. I was looking for a 3A reg in case I need a little more for more channel strips later. I am having a tough time finding a negative regulator. LM333 appears to be obsolete. Any ideas? Nothing on the Fairchild or TI sites. Maybe I am not looking in the right places.

Thanks!
 
For future reference, you can also use LM317/337 standard 1amp or 1.5amp adjustable regulator (or a zener if you're so inclined) with an emitter follower. Just use a high power transistor.
 
You could do it like this:

5ALABVOE3.GIF


You can of course do the same with a negative power supply, in that case you will need a NPN power transistor.
 
It seems there was a thread recently where a member here repaired a broken PS using a pass element to boost the current output of 3 terminal regulators. Good to look at a production design as a starting point. That repair thread posted a copy of the schematic.

JR
 
riggler said:
John, do you remember what it was for? I am not seeing anything in the Lab, but maybe I am using bad search terms. Thanks!
Damian

no I don't remember but here it is http://www.groupdiy.com/index.php?topic=48716.0

I tried searching for it using power supply, repair, transistor, etc and didn't find it, then searched posts made by the poster.

I don't know that this design is optimal, but it is a production design so should work...



JR

PS: You owe me several minutes...  8)
 
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