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

PLaying with ClassD again
PLaying with ClassD again
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 11th February 2008, 08:35 AM   #1
TroelsM is offline TroelsM  Denmark
diyAudio Member
 
TroelsM's Avatar
 
Join Date: May 2003
Location: AARHUS. DK
Default PLaying with ClassD again

Hi.

Here's a small peak at my latest classD-fumblings.

I concentrated on the output-stage at first. It's build around a IR2110 and two FQB19n20L.

Here's a few pics of the output-waveforms before the filter. First a 115Vpp square and the rising/faling edge. Rise/fall-time is approx. 35nS (10%->90% of voltage-range). Looks promising.

Click the image to open in full size.
Click the image to open in full size.
Click the image to open in full size.

Next on the to-do is the modulator-scheme. Most likely selvf-osc in some form. Any ideas? What's your favorite-scheme of the day?

Please click this link to see more info: http://kofoedmejer.squarespace.com/classd-amplifier/

Regards TroelsM
__________________
Need more time...
  Reply With Quote
Old 11th February 2008, 08:39 AM   #2
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
PLaying with ClassD again
Hi

I have tried clocked version, works great. Ucd's are also great...really hard to say what to go for... ucd is more simple if you make it all discrete

Hope you will have bigger cap for upper gate drive, when you will go into hard clipping

Are those pics befere or after LC filter?
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th February 2008, 08:42 AM   #3
TroelsM is offline TroelsM  Denmark
diyAudio Member
 
TroelsM's Avatar
 
Join Date: May 2003
Location: AARHUS. DK
Waveforms are taken before filter. Just edited my prev. post to reflect this.

Regards
__________________
Need more time...
  Reply With Quote
Old 11th February 2008, 08:48 AM   #4
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
PLaying with ClassD again
Hi

Bit you to it Before LC you won't have really any problems, you should connect LC filter too, and see what you get there...
Do you have any rail-rail decoupling caps on board?
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th February 2008, 08:54 AM   #5
TroelsM is offline TroelsM  Denmark
diyAudio Member
 
TroelsM's Avatar
 
Join Date: May 2003
Location: AARHUS. DK
Hi.

Each rail has a 330uF/100V e-cap and a smaller film-cap. There is no caps from rail to rail. Why?
__________________
Need more time...
  Reply With Quote
Old 11th February 2008, 08:55 AM   #6
lumanauw is offline lumanauw  Indonesia
diyAudio Moderator Emeritus
 
lumanauw's Avatar
 
Join Date: Oct 2002
Location: Bandung
Send a message via Yahoo to lumanauw
Is there any good clocked classD schematic with feedback taken after LC filter?
  Reply With Quote
Old 11th February 2008, 09:03 AM   #7
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
PLaying with ClassD again
Hi

@ TroelsM

You will need noise free rails as much as possible, this is why you should have rail-rail cap too, 2x100n or 1x220-330nF, try to find some good ones

@lumanauw

Yes there is as far as you ask me, made by fredos and then redesigned by alexclaire
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th February 2008, 01:34 PM   #8
TroelsM is offline TroelsM  Denmark
diyAudio Member
 
TroelsM's Avatar
 
Join Date: May 2003
Location: AARHUS. DK
@Luka

Output filter was connected at the time, but the plot shows the pre-filter waveform.

The cap on the floating supply is not very big, but I will change it later. Right now its not the biggest problem.

Thanks for the help. Re-visit the tread later to see more.

Regards
__________________
Need more time...
  Reply With Quote
Old 20th February 2008, 06:10 AM   #9
TroelsM is offline TroelsM  Denmark
diyAudio Member
 
TroelsM's Avatar
 
Join Date: May 2003
Location: AARHUS. DK
Doh!

Click the image to open in full size.

Regards TroelsM
__________________
Need more time...
  Reply With Quote
Old 20th February 2008, 06:48 AM   #10
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
PLaying with ClassD again
Hi

What are you trying to say?
It is better then my...
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote

Reply


PLaying with ClassD againHide 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
New to ClassD DarkOne Class D 2 24th September 2006 04:11 PM
looking for classD follower lumanauw Class D 2 17th October 2005 12:54 AM
Learning about classD lumanauw Class D 34 24th March 2005 01:39 AM
what's better, a mid playing high, or a tweet playing low??? cody6766 Multi-Way 10 20th February 2005 09:40 PM
GC VS classD etalon90 Chip Amps 0 3rd November 2004 05:29 PM


New To Site? Need Help?

All times are GMT. The time now is 10:26 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki