Electronics > Projects, Designs, and Technical Stuff
Any reason I shouldn't use a TL431 as a virtual ground?
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ajb:
With a 78xx OR a TL431, just be aware of how much current you pull out of it and in which direction.  That's one big downside of either approach as opposed to a two-quadrant virtual ground supply.
bd139:

--- Quote from: Benta on November 14, 2018, 03:39:54 pm ---I think the TL431 idea is fine, I'd go with it.


--- End quote ---

Trying it now :)

Couldn't find my bag of 78L33 parts. Only got MCP1700-3302's and they have max input of 6V :(


--- Quote from: ajb on November 14, 2018, 03:48:49 pm ---With a 78xx OR a TL431, just be aware of how much current you pull out of it and in which direction.  That's one big downside of either approach as opposed to a two-quadrant virtual ground supply.

--- End quote ---

I've got a spare LM358 in the design which I am using to buffer the TL431. That can sink and source enough. May need to pull the output down as the LM358 doesn't like switching from one mode to the other without some horrid distortion. Not sure if that will happen or have any side effects yet.

I did consider buying a tube of LMC6482 for this but they're really expensive in comparison. Got a tube of 50x LM358 (a lifetime supply) for the same price as 4x LM6482.
nuno:
Check the stability graph on the 431's datasheet.
bd139:
Yep already looked at that. First thing I did was make it oscillate (doesn't need a cap on the output)  :-DD
Benta:

--- Quote from: bd139 on November 14, 2018, 03:52:01 pm ---I did consider buying a tube of LMC6482 for this but they're really expensive in comparison. Got a tube of 50x LM358 (a lifetime supply) for the same price as 4x LM6482.

--- End quote ---

LMC6482: my absolute favorite low power opamp. It's always available in my parts drawer.  :-+
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