Questions on reference and noise in the super regulator - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 30th July 2008, 06:04 PM   #1
Lucien is offline Lucien  United Kingdom
diyAudio Member
 
Join Date: Nov 2007
Question Questions on reference and noise in the super regulator

I've been studying the design of the super regulator(s) with the intention of building a SMD version for myself. I think I understand most of the circuit functionality (with the possible exception of the startup constant current source - analog electronics is not my forte) but have hit a stumbling block when it comes to an alternative for the LM329.

I've come across the ADR5045, which lists output voltage noise as 6.6 uVrms for 0.1 Hz to 10 Hz and 280 uVrms for 10 Hz to 10 kHz. Now the LM329 datasheet lists it's RMS noise as typically 7 uV for 10 Hz to 10 kHz. Would this mean the ADR5045 is a poor substitue as its 10 Hz to 10 kHz figure is higher, or should we instead look at the 0.1 Hz to 10 Hz figure as the output of the regulator is filtered by a ~2.7 Hz low pass filter?

I've also looked at a regulators such as the ADR435, which produces a 5V reference output from an input voltage of 7V to 18 V. (Datasheet ) Now the catch for this part is the minimum Vin is 2V above Vout, meaning it can't be a drop in replacement for the LM329.

But if my output rails are +/- 10V, I wonder if I could do this (omitting the capacitors and most of the supply side of the circuit):

Click the image to open in full size.

By tying the output of the second ADR435 to ground, it sees 15V from Vin to GND, while providing me with a -5V reference. Only thing is I doubt the GND pin can be hooked up in that way.

Alternatively, based on Fig. 36 in the ADR435 datasheet, I could try this:

Click the image to open in full size.

Ignore the AD8610 tag, it could be any op-amp, I just used the first part on the list. In this design, I can imagine that the voltage noise being fed into the 825 is then a function of the op-amp, and based on that I don't know if the dual ADR435 design would be a better solution. Or have I got it wrong and neither one is feasible?
  Reply With Quote
Old 4th August 2008, 09:08 PM   #2
Lucien is offline Lucien  United Kingdom
diyAudio Member
 
Join Date: Nov 2007
um, anyone?
  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
Super Regulator TheDriver Parts 2 21st July 2008 10:54 AM
Lithos regulator - A new super regulator? peranders Parts 7 8th May 2008 02:01 PM
cracking noise in reference Tony.ca Multi-Way 12 18th October 2006 07:20 PM
Super Regulator for DAC rockytro Digital Source 11 19th May 2006 07:31 PM
Reference zener in Series regulator claudio Power Supplies 13 5th February 2005 03:13 PM


New To Site? Need Help?

All times are GMT. The time now is 08:42 AM.


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