Capacitor Ripple Current vs Operational Temp - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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 4th July 2016, 06:49 PM   #1
ainami is offline ainami  United States
diyAudio Member
 
Join Date: Sep 2004
Location: California
Default Capacitor Ripple Current vs Operational Temp

Hey all,

I'm trying to decide between two caps for the regulator section of a power supply. They are the pre and post capacitors for +/-15V regulators.

Nichicon KW - 1000uf 25V
Ripple Current: 950mA
Lifetime at Temp: 2000 Hrs at 85 deg C

Nichicon KA - 1000uf 25V
Ripple Current: 680mA
Lifetime at Temp: 2000 Hrs at 105 deg C

The KW allows for higher ripple current, but the KA shows a higher temp rating. Based on my reading on ripple current ratings, it looks to be a sliding scale based on temperature. If I am correct in my assumptions, a capacitor will have a higher ripple current capability when operated at a lower temp. So, ultimately, what is the real difference between these two capacitors.

These will be pre/post regulator filters for the op amp sections of a DAC. There are 5 Class A op amp circuits (each with about 28ma quiescent current), so there will definitely be some current being run through the system. The caps will be mounted right next to the regulator heatsinks, which will measure about 55-60 degrees C. The caps will warm up with the current and will run somewhere between 30-40 deg C.

Of course, I'm really after sound quality, since these caps will not be run in an auto or industrial scenario. However, which one of these caps will perform better in my situation?
  Reply With Quote
Old 4th July 2016, 06:57 PM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Use the 105C parts as they will have a longer life. That would be my advice. Your actual ripple current is going to be way below either parts maximum, and although either will perform well initially, in 10 or 20yrs time it may be a different story... and yes, a well designed circuit should certainly hold its performance for at least 10 to 15 years before any hint of cap trouble creeps in.

Manufacturers often learnt this the hard way. Dried out and failed 'standard cooking grade' parts are a fact of life in busy service departments.
__________________
-------------------------------------------------------
Installing and using LTspice IV. From beginner to advanced.
  Reply With Quote
Old 4th July 2016, 07:25 PM   #3
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Quote:
Originally Posted by ainami View Post
Hey all,

I'm trying to decide between two caps for the regulator section of a power supply. They are the pre and post capacitors for +/-15V regulators.

Nichicon KW - 1000uf 25V
Ripple Current: 950mA
Lifetime at Temp: 2000 Hrs at 85 deg C

Nichicon KA - 1000uf 25V
Ripple Current: 680mA
Lifetime at Temp: 2000 Hrs at 105 deg C

The KW allows for higher ripple current, but the KA shows a higher temp rating. Based on my reading on ripple current ratings, it looks to be a sliding scale based on temperature. If I am correct in my assumptions, a capacitor will have a higher ripple current capability when operated at a lower temp. So, ultimately, what is the real difference between these two capacitors.

These will be pre/post regulator filters for the op amp sections of a DAC. There are 5 Class A op amp circuits (each with about 28ma quiescent current), so there will definitely be some current being run through the system. The caps will be mounted right next to the regulator heatsinks, which will measure about 55-60 degrees C. The caps will warm up with the current and will run somewhere between 30-40 deg C.

Of course, I'm really after sound quality, since these caps will not be run in an auto or industrial scenario. However, which one of these caps will perform better in my situation?
First thing you need to do is cool off those regulators as they will be a constant thorn in your side.

Where did you find caps with such lousy ripple current?

These would be fine and there are MANY others.

EEU-FM1E102 Panasonic Electronic Components | Capacitors | DigiKey

EKZE250ELL102MK20S United Chemi-Con | Capacitors | DigiKey

Note the longer life hours and higher ripple current and the price is OK.

Heat is what kills electronics so if you want things to last, don't cook them.

Happy Fourth

G
  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
HELP: relationship between capacitor ripple current and can size CharlieLaub Parts 3 9th January 2014 01:47 AM
Help with Ripple Current GOR3 Power Supplies 11 11th January 2013 02:10 AM
Ripple current in input capacitor too high? eem2am Power Supplies 25 5th October 2011 08:38 AM
Ripple current ? woody Solid State 2 12th January 2009 11:09 PM
input capacitor ripple current rating for push-pull zilog Power Supplies 3 28th February 2007 11:08 AM


New To Site? Need Help?

All times are GMT. The time now is 01:10 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki