PA input voltage simple precision 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 16th June 2010, 08:17 PM   #1
diyAudio Member
 
Join Date: Mar 2010
Location: Paris
Default PA input voltage simple precision regulator

My spec.were:
  • +/-40-60V input voltage
  • +/- 17V 1% output voltage without triming
  • 50mA of nominal current
  • low noise, low output impedance, low ripple
  • simple design
And after investigating several solutions, I had the following idea. Note that voltage reference and op amp are fed by output voltage. I still haven't tried this solution and would be interested to know if some one here had some experiments with something like this.

Device list:
RA1
Res.
9,09K


RA2
Res.
9,09K


RA3
Res.
3,65K


RA4
Res.
3,65K


RA5
Res.
5,23K


RA6
Res.
5,23K


RA7
Res.
20K


RA8
Res.
20K


RA9
Res.
9,09K


RA10
Res.
9,09K


CA1
Cap.
10u


CA2
Cap.
10u


CA3
Cap.
10u


CA4
Cap.
10u


CA5
Cap.
33pf


CA6
Cap.
33pf


ICA1
Op. Amp.


LT1677
ICA2
Op. Amp.


LT1677
DA1
Zener
8.2V


DA2
Zener
8.2V


DA3
Sh.Reg.
10V
LM4040
DA4
Sh.Reg.
10V
LM4040
TA1
Bjt


KSC2690
TA2
Bjt


KSA1220
Attached Images
File Type: png sym-regul.png (16.6 KB, 80 views)
  Reply With Quote
Old 17th June 2010, 05:59 AM   #2
RJM1 is offline RJM1  United States
diyAudio Member
 
Join Date: Jan 2010
Location: Titusville, Fl.
Well it would work but not with those resistor values. The ratio of the voltage divider network at the negative input of the op-amp (RA3/RA5) should be “1+(17(output voltage)/8.2(zener reference) )= 2.073”. Yours is “1+3.65k/5.23k = 1.697” which would give you an output voltage of 13.92V. One other thing is that the current through DA1 which is set by RA1 should be set to the zener test current of the diode which can be found on the diodes data sheet. With RA1 set at 9.09K the current through the zener is slightly less than 1ma which seems too low, this will lower the diode’s reference voltage.
  Reply With Quote
Old 17th June 2010, 07:01 AM   #3
diyAudio Member
 
Join Date: Mar 2010
Location: Paris
Well excuse me for my device list which is particularly unclear.
On the schematic there is two devices represented as zeners. In fact the voltage réference is not actually a zener it is an LM4040 10V shunt regulator which is suppose (according to its DS) to work very well with less than 1mA.

Regards
  Reply With Quote
Old 17th June 2010, 03:19 PM   #4
RJM1 is offline RJM1  United States
diyAudio Member
 
Join Date: Jan 2010
Location: Titusville, Fl.
Yes but your DA1 and DA2 are the voltage references for you 17V and are listed in your device list as 8.2V zener diodes. Your LM4040's just let the pass transistor turn on enough to get voltage to your op-amp at start up so that it can then regulate to the 8.2V zener that you are using as a voltage reference to the op-amp for your 17V output. So in fact the voltage reference that you are using to compare you 17V to is the 8.2V zener diode and not your LM4040 10V shunt regulator.Or maybe your device list and your schematic don't match?

Last edited by RJM1; 17th June 2010 at 03:21 PM.
  Reply With Quote
Old 17th June 2010, 04:18 PM   #5
diyAudio Member
 
Join Date: Mar 2010
Location: Paris
Yes you are right the device is unclear and there is a mistake in it: the references to to the voltage reference and the zener are inverted.
  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
Simple voltage regulator get crazy... and so am I Malefoda Power Supplies 12 18th August 2009 10:38 PM
About a very very simple class D PA amp gaetan8888 Class D 8 13th March 2009 02:21 PM
Precision Voltage Divider - diy redrabbit Equipment & Tools 3 24th July 2008 04:16 PM
Precision PA conversion help needed PRNDL Tubes / Valves 10 6th December 2007 06:14 PM
Simple Low Power Voltage Regulator rjm Power Supplies 18 28th September 2005 03:48 PM


New To Site? Need Help?

All times are GMT. The time now is 04:20 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