Ripple eater - 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 17th January 2012, 04:14 PM   #1
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Ripple eater

Great article by W. Morong

Simple power supply ripple rejection for battery systems
  Reply With Quote
Old 18th January 2012, 03:17 AM   #2
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
E.D. is good for ads...

Not so good for circuits...
__________________
Seven Transistor Labs
Projects and Resources
  Reply With Quote
Old 18th January 2012, 09:17 AM   #3
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by Sch3mat1c View Post
E.D. is good for ads...

Not so good for circuits...
Yeah, it is a ripple eater with a small appetite:

Contrary to what the article claims, the circuit doesn't even arrive at the modest 40dB rejection.

By removing one of the transistors, things begin to improve: it is now ~50dB.

But the real breakthrough is achieved with a more conventional CFP: we are now better than 60dB, with the added bonus of a smaller quiescent current (and simpler circuit).

The output impedance may not be as low, but this could also be fixed without great difficulty.
Attached Images
File Type: gif RippleE.GIF (61.1 KB, 285 views)
File Type: gif RippleEi.GIF (53.4 KB, 273 views)
File Type: gif RippleEii.GIF (55.4 KB, 277 views)
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 19th January 2012, 02:40 AM   #4
diyAudio Member
 
Sch3mat1c's Avatar
 
Join Date: Jan 2003
Location: Milwaukee, WI
Send a message via ICQ to Sch3mat1c Send a message via AIM to Sch3mat1c
Getting more than ~50dB, particularly at high frequencies, is made difficult by Early effect and capacitor ESR. I know a guy who works in quirky electronics, high sensitivity, wide band, low noise sorts of stuff, who once used a double or triple stage capacitance multiplier to achieve nanovolt noise levels from particularly dirty SMPS rails. This can be done with low dropout by chaining the stages from the same RC filter; after the first ~0.7V from the first emitter follower, you only need ~0.2V or so (Vce(sat) min) for each subsequent stage, which can be generated with a small leakage current down the divider (equivalent to R2 in your first schematic).

Tim
__________________
Seven Transistor Labs
Projects and Resources
  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
John Linsley Hood Ripple Eater - Part 2 AlanElsdon Group Buys 198 29th May 2013 12:44 AM
John Linsley Hood Ripple Eater jonclancy Group Buys 270 9th May 2012 01:07 PM
PP PSU: How much ripple is too much ripple? DrewP Tubes / Valves 10 11th September 2011 05:59 AM
Help with ripple akis Solid State 18 4th September 2009 09:19 PM
How much ripple?? JDeV Tubes / Valves 23 2nd April 2003 11:05 PM


New To Site? Need Help?

All times are GMT. The time now is 04:42 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