PSUD2 Q on regulator

JoshK · 28th August 2007, 06:46 PM

Does anyone know how to model a shunt regulator in PSUD? I know it must be more than a current tap because the regulator drops some voltage and a series resistor and current tap would be an illegal combination, or rather unchoseable.

I am trying to model an LC > Janus shunt regulator > maybe another LC for channel seperation.

dsavitsk · 28th August 2007, 06:52 PM

Quote:

Originally posted by JoshK
I am trying to model an LC > Janus shunt regulator > maybe another LC for channel seperation.

I can't answer the original question, but I had a regulator followed by an RC for channel separation -- ruined the amp. Jumpering over the R was transformative.

JoshK · 28th August 2007, 07:51 PM

As best as I can tell you don't model a regulator in PSUD.

Dave, thanks for your experience. I think I will alligator clip it and try it out and compare to without.

DougL · 28th August 2007, 08:16 PM

Best you can do in PSUD2 is model the passive part up to the shunt reg for voltage and current ripple, as well as any instability.

use the step function to see if change in load will ring.

Doug

EC8010 · 28th August 2007, 08:24 PM

Any regulator looks like a constant current load looking into its input.

dsavitsk · 28th August 2007, 08:40 PM

Quote:

Originally posted by JoshK
As best as I can tell you don't model a regulator in PSUD.

Dave, thanks for your experience.

It's Doug: http://www.diyaudio.com/forums/showt...15#post1288215

JoshK · 28th August 2007, 08:50 PM

Sorry...guess I remembered wrong.

JoshK · 29th August 2007, 02:01 AM

Quote:

Originally posted by EC8010
Any regulator looks like a constant current load looking into its input.

Not particularly sure what all that implies to my question. Do you mean that anything thereafter is moot as it shield the prior passives from the suceeding stages?

SY · 29th August 2007, 04:03 AM

I think he was referring to the load that the filter sees. For a shunt regulator, this is obvious. For a series regulator, the load is the collector of the pass transistor, which has a high dynamic impedance.

dsavitsk: Your experience with the RC after the reg is an illustrative example of what happens when you kill the dynamic regulation.

dsavitsk · 29th August 2007, 05:07 AM

Quote:

Originally posted by SY
dsavitsk: Your experience with the RC after the reg is an illustrative example of what happens when you kill the dynamic regulation.

And how! It was a good lesson learned -- the resistance was small (20R) and the caps after are relatively large, but I could never quite get the amp right.

This brings up a question: when modeling a PS in PSUD, I generally check for ringing by using the stepped load function. PSUD will show the change in voltage at the load, but the speed at which it changes can differ (in the supplies I've been playing with, it is usually between .5 and 1 second with a 2mA change in draw). So, do I want that change to be fast or slow?

28th August 2007, 06:46 PM	#1
JoshK diyAudio Member Join Date: May 2004 Location: Toronto, ON	PSUD2 Q on regulator Does anyone know how to model a shunt regulator in PSUD? I know it must be more than a current tap because the regulator drops some voltage and a series resistor and current tap would be an illegal combination, or rather unchoseable. I am trying to model an LC > Janus shunt regulator > maybe another LC for channel seperation.

28th August 2007, 08:16 PM	#4
DougL diyAudio Member Join Date: Feb 2004 Location: Wheaton IL. Blog Entries: 25	Best you can do in PSUD2 is model the passive part up to the shunt reg for voltage and current ripple, as well as any instability. use the step function to see if change in load will ring. Doug __________________ Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well) Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus

28th August 2007, 08:24 PM	#5
EC8010 diyAudio Moderator Join Date: Jan 2003 Location: Near London. UK	Any regulator looks like a constant current load looking into its input. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...

29th August 2007, 04:03 AM	#9
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	I think he was referring to the load that the filter sees. For a shunt regulator, this is obvious. For a series regulator, the load is the collector of the pass transistor, which has a high dynamic impedance. dsavitsk: Your experience with the RC after the reg is an illustrative example of what happens when you kill the dynamic regulation. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

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28th August 2007, 07:51 PM	#3
JoshK diyAudio Member Join Date: May 2004 Location: Toronto, ON	As best as I can tell you don't model a regulator in PSUD. Dave, thanks for your experience. I think I will alligator clip it and try it out and compare to without.

28th August 2007, 08:50 PM	#7
JoshK diyAudio Member Join Date: May 2004 Location: Toronto, ON	Sorry...guess I remembered wrong.

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