Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Class D Switching Power Amplifiers and Power D/A conversion

heating in inductor ( LC Filter )
heating in inductor ( LC Filter )
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
Thread Tools Search this Thread
Old 20th September 2008, 03:45 PM   #1
yanuarbob5150 is offline yanuarbob5150  Indonesia
diyAudio Member
Join Date: May 2008
Default heating in inductor ( LC Filter )

hi all, i am in final step to design 100 W rms class D power amplifier. Recently, i am in experiment to design low cost power mosfet, now i have problem in inductor ( part of LC filter ). The inductor being warm and at several minutes the inductor hot!!!!!!!!!!!

in LC filter, the inductor design i use toroidal core ( dimension not measured ) with AWG cooper - wire with diametre 1.2mm. I use LCR meter and get the inductor values 21.7uH.

can anybody help me to design the inductor with proper concepts?????
escpecially in relation with heating of an inductor.

  Reply With Quote
Old 20th September 2008, 08:13 PM   #2
dweekie is offline dweekie  United States
diyAudio Member
Join Date: Sep 2006
You may want to browse this for some ideas.

  Reply With Quote
Old 23rd September 2008, 08:13 AM   #3
Ouroboros is offline Ouroboros  England
diyAudio Member
Ouroboros's Avatar
Join Date: Dec 2003
Location: Nottingham UK
I have found that inductor core losses (not copper losses) usually dominate the total loss (at idle), especially if you use the wrong type of core. Many commercially available off-the-shelf inductors are not designed for operation at the 300kHz or so that a Class-D amplifier will be working at. You usually have to use an inductor with a much larger core than you might expect to keep the losses low.

I have had very poor results using dust-iron toroids. The best toroidal cores I've used for the output filter have been the fairly recently introduced gapped ferrite toroids from Ferroxcube that are designed for this sort of operation. These are made of a high-grade ferrite with a precision gap sawn in them, which is then resin filled to restore the mechanical strength. Alternatively, the traditional RM8 and RM10 cores work well, and are available in a range of different ferrite types. The documentation for RM cores from different manufacturers is easy to find on the web.
  Reply With Quote
Old 23rd September 2008, 11:19 AM   #4
Pafi is offline Pafi  Hungary
diyAudio Member
Join Date: May 2004
Location: Budapest
Generally: the higher the number of turns, the lower the core loss. A bad iron powder core also can be made better by cutting a narrow gap (or two, 4, etc...) into it. (Gap->low Al->higher number of turn->smaller dB/dt->less core loss.)
  Reply With Quote


heating in inductor ( LC Filter )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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Copper coil inductor vs. round core inductor tomchaoda Pass Labs 7 21st September 2011 05:42 AM
smps output filter inductor design zilog Power Supplies 7 31st August 2008 12:47 AM
SMPS Output filter inductor calculation. corrieb Car Audio 7 28th October 2005 04:47 PM
~30mH inductor for use in pi filter Zodiac Parts 6 29th September 2003 11:38 AM
X-BOSOZ 1st order inductor filter Ignatz Pass Labs 14 17th April 2003 11:01 PM

New To Site? Need Help?

All times are GMT. The time now is 12:29 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio