Bipolar discrete shunt regulators - Page 13 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 5th February 2009, 08:09 AM   #121
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by steenoe
This is the latest schematic. Still needs the last few changes to be added.
http://www.diyaudio.com/forums/showt...72#post1733072


I would change Z2 to an LED, and R5 to an LM334 CCS (with 12 ohms as set resistor). This does limit Vin to 40V though, if that is a problem, make a provision to put a zener in series with the LM334.

RV15 is the trimpot. I would just use a fixed resistor here; the absolute Vout is not critical and the resistor can be easily calculated.
What I haven't checked, but what I would put on the new pcb, is a resistor from Vout to the top of the reference zener. That way, we could get some current into the zener that is independent from the current through the error amp Q3. Q3 current varies with load and (a bit) with input ripple so keeping the zener current relatively independent helps also. Don't know how big the effect will be, but worth a try.

Jan Didden
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W S Maugham
Check out Linear Audio!
  Reply With Quote
Old 5th February 2009, 08:22 AM   #122
GK is offline GK  Australia
Account disabled at member's request
 
Join Date: Jan 2006
Quote:
Originally posted by Onvinyl


That shouldn't be too though, especially with a shunt reg, since a shunt reg splits the loops (raw supply and regulated supply) quite effectively.

I agree. That's what I way trying to show in that LTspice sim. Even a rudimentary layout with just one straight ground and power track can be arranged such that PSR is pretty much a non-issue.

The effective reduction in output impedance due to the earth return currents from the load are an other issue though!

I've actually layed out and built that regulator, layed out from left to right as drawn in the schematic with just a low impedance top and bottom ground plane. PSR tested as good as expected. In theory the output impedance isn't as good as it could be with elaborate star point earthing, but this is irrelevant in my case as for the intended application the load only draws a dynamic current of about 50uA.

Layout considerations depend a lot on the application.

Cheers,
Glen
  Reply With Quote
Old 5th February 2009, 02:15 PM   #123
syn08 is offline syn08  Canada
Account disabled at member's request
 
Join Date: Aug 2005
Location: Toronto
Guys,

I really want to understand what's the reasoning for building such a discrete regulator. I understand how they work, I have simulated their performances (and they seems to be decent) but I have not build and measured one.

However, I have simulated, build and estimated the performances of the parallel regulator in attached schematic. The measured results are really very, very good, beyond what I think it will ever be needed for audio and BTW, they match the simulations within 25% (or at least that's how much I bothered to look into). Note that this is a completely not optimized design, I haven't even bothered to try a current source or other references beyond a LED. BTW, the output noise is comparable to the Jung serial regulator.

To compare with the discrete version, I'll put in the next two posts the PSRR and the output impedance for a +30V version (mine are +/-17V).

I'll let you compare the performances and the complexities/sizes/costs. Again, beyond a) limited to 30V output and b) not that much fun to deal with, I don't see much of a reason why one would build the discrete version.
Attached Images
File Type: jpg par_reg_sch.jpg (23.3 KB, 2993 views)
  Reply With Quote
Old 5th February 2009, 02:20 PM   #124
syn08 is offline syn08  Canada
Account disabled at member's request
 
Join Date: Aug 2005
Location: Toronto
Default Psrr

Opamp is THS4031. Vertical scale is PSRR in dB.
Attached Images
File Type: jpg psrr.jpg (93.8 KB, 2165 views)
  Reply With Quote
Old 5th February 2009, 02:21 PM   #125
syn08 is offline syn08  Canada
Account disabled at member's request
 
Join Date: Aug 2005
Location: Toronto
Default Output impedance

Injecting current at the output. Vertical scale is the output impedance in ohm.
Attached Images
File Type: jpg output_impedance.jpg (96.1 KB, 2038 views)
  Reply With Quote
Old 5th February 2009, 02:44 PM   #126
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
I agree that there are millions of ways to skin this particular cat. But, being diy, I often enjoy discovering and building stuff, even if in some far away corner of this universe there may be someone who can do me one better.
It's the enjoyment of finding out and getting it to work that counts for me and for a lot of other people in this thread.
I would be disappointed if this design keeps on swaying to and fro without actually getting done!
Let's stick with the original design, finetune it, and getting it going. As a reg, it'll be pretty good and worthwhile your work and mony.

Jan Didden
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W S Maugham
Check out Linear Audio!
  Reply With Quote
Old 5th February 2009, 03:12 PM   #127
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Jeez, Ovidiu, your reg is depressingly simple

As I always distrust the computer, maybe you find time in a bored moment to post some measured numbers. If that toy comes close to a Jung/Didden in the real world, I'm deeply impressed.

So much simplicity demands being used in the next project

Have fun, Hannes
  Reply With Quote
Old 5th February 2009, 03:21 PM   #128
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Alan Wright

Super Reg
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
  Reply With Quote
Old 5th February 2009, 03:52 PM   #129
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Schematic?

Seems his site prefers selling his stuff, no schematic. It's ok, but then I don't understand your reply

Have fun, Hannes
  Reply With Quote
Old 5th February 2009, 04:20 PM   #130
diyAudio Member
 
apassgear's Avatar
 
Join Date: Nov 2002
Location: Viña del Mar, Torreon
Quote:
Originally posted by janneman

Let's stick with the original design, finetune it, and getting it going. As a reg, it'll be pretty good and worthwhile your work and mony.

Jan Didden
Yes, we will do that...

I have troubles with my IP so some emails have not gone thru, will take a couple of days to organize work.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
DIY Discrete regulators gareth Digital Source 17 3rd February 2008 01:04 PM
CCS fed shunt regulators mark_titano Tubes / Valves 3 30th May 2005 03:14 PM
Questions about shunt regulators Bricolo Parts 5 16th September 2003 10:47 AM
LCAudio shunt regulators OliverD Digital Source 4 16th December 2002 08:27 PM
Discrete voltage regulators. JoeBob Solid State 1 18th March 2002 05:25 AM


New To Site? Need Help?

All times are GMT. The time now is 04:23 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2