Electronics > Beginners
TL431 linear power supply
<< < (30/32) > >>
not1xor1:

--- Quote from: imo on December 25, 2018, 09:39:31 am ---With a 6.3mA current source and 2n2 ser 100ohm comp.
3V/5A
25V/5A

--- End quote ---

I confirm the circuit works as showed in your screenshot.
Il looks like the problems arises from the placement of the AC source that yields awful results when placed like I did.

I've to check more carefully the subject to understand what is wrong.
Thanks

P.S.
since I suspected something is wrong in your measurement method I made a quick transient test, switching between 5mA and 1A on 25V output and the output goes awry... huge oscillations... see below

iMo:
Measurement method?? - That is the question! :)

I took the LT/ADI method - see the link above.
You previously did with a simple AC sweep.

Your oscillation - are you using zero ESR output capacitors?

Below with "real capacitors", no oscillation, a small ringing w/ 160mVpp amplitude..
not1xor1:

--- Quote from: imo on December 27, 2018, 02:25:04 pm ---Measurement method?? - That is the question! :)

I took the LT/ADI method - see the link above.
You previously did with a simple AC sweep.

Your oscillation - are you using zero ESR output capacitors?

Below with "real capacitors", no oscillation, a small ringing w/ 160mVpp amplitude..

--- End quote ---

That is a different method but should yield similar results.

I used models of real capacitors too...
I also tried to add a resistor of 0.5 ohm in series to each capacitor with no result.
BTW this is LTspice XVII x64 Jun 15 2018 running in linux.
I tried both alternate and normal solver, 4 threads and single thread.
No matter what I try I always get oscillations.
Might that depend on the TL431 model I'm using here ...?  :-//

in the comment I read:

--- Quote ---** Released by: Analog eLab Design Center, Texas Instruments Inc.
* Part: TL431
* Date: 12/14/2009
* Model Type: Transient and AC 
* Simulator: PSPICE 
* Simulator Version: 16.0.0.p001
* Datasheet: SLVS543J - AUGUST 2004 - REVISED DECEMBER 2005

--- End quote ---
iMo:
Here is the latest LTspiceXVII, and with the latest Bordodynov library (LTspiceXVII_2018Dec21.zip).
Below the TL431s offerings..
PS: tried with several TL431 models and got similar results as above..

And the library is here, for the latest download go to "Additional links :"
xavier60:

--- Quote from: not1xor1 on December 27, 2018, 08:14:20 am ---

P.S.
since I suspected something is wrong in your measurement method I made a quick transient test, switching between 5mA and 1A on 25V output and the output goes awry... huge oscillations... see below


--- End quote ---
I think that C1 and R17 should be made larger, I'd start with 1uF and 1K
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod