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

Class D AMP using only TL494
Class D AMP using only TL494
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 29th December 2014, 11:08 PM   #1
mashah1220 is offline mashah1220
diyAudio Member
 
Join Date: Dec 2014
Default Class D AMP using only TL494

Hey Guys.

I am trying to make a D-Class Power Amplifier to drive a 10W 8 Ohm Loudspeaker. However, I want to make the class D Amp using only TL494, BJT's and MOSFETS. The reason is that in my area, specific IC's are hard to come by. Therefore, I need to make use of only BJT's, MOSFETS, other passive components and the TL494 chip.

I am attaching a pic of my LTSpice Simulation, and the Simulation file itself as well. I cannot figure out what I am doing wrong. I have wandered aimlessly around websites but cannot not find a reasonable answer. Please Help...

Click the image to open in full size.

P.S: If you want the TL494 LTSpice Model, I am attaching the whole library that contains it as well. Thank you so Much.....
Attached Files
File Type: asc D-Class TL494.asc (4.5 KB, 284 views)
File Type: zip LTSpice Lib.zip (244.3 KB, 400 views)
  Reply With Quote
Old 30th December 2014, 06:58 PM   #2
Acca is offline Acca  Serbia
diyAudio Member
 
Acca's Avatar
 
Join Date: Nov 2011
Class D AMP using only TL494
You can't modulate it by this way.You can try this:
Attached Images
File Type: gif Klas D3.GIF (16.6 KB, 1419 views)
  Reply With Quote
Old 30th December 2014, 07:05 PM   #3
Acca is offline Acca  Serbia
diyAudio Member
 
Acca's Avatar
 
Join Date: Nov 2011
Class D AMP using only TL494
And few pics:
Attached Images
File Type: jpg PTDC0031.JPG (86.0 KB, 1337 views)
File Type: jpg PTDC0029.JPG (75.9 KB, 1248 views)
File Type: jpg PTDC0027.JPG (95.7 KB, 1215 views)
  Reply With Quote
Old 31st December 2014, 12:52 PM   #4
sweetperfume is offline sweetperfume  India
diyAudio Member
 
Join Date: Dec 2010
Location: INDIA
what are the values of the diodes?
  Reply With Quote
Old 31st December 2014, 05:48 PM   #5
Acca is offline Acca  Serbia
diyAudio Member
 
Acca's Avatar
 
Join Date: Nov 2011
Class D AMP using only TL494
Fast, like uf4007,...
  Reply With Quote
Old 3rd January 2015, 01:12 PM   #6
Th3 uN1Qu3 is offline Th3 uN1Qu3  Romania
diyAudio Member
 
Join Date: Feb 2010
Location: Bucharest
Send a message via Yahoo to Th3 uN1Qu3
Ah, hello Acca. Nice to see you're still messing around with this.

I've taken a rather long break but now that i have some spare time i have revisited the project in the past week or so.

I have designed a decent PCB and moved all my components from the other one. There is now room for all the parts that were added later on the old one. It works great so far. I made two side by side so i can make a bridged amplifier working at 12 volts, as my goal now is to make some small powered speakers with two 2" drivers each.

I have bought these little speakers for like $2.50 a pop, and found them to sound brilliant for what they are. They are very bright, clean and can handle a bit of power. I have bought several other 2" speakers in the past from the same store and they sounded like crap, so i abandoned the project. But these ones are better than expected, so i will be buying more of them and building a few speakers. I will also likely build a small subwoofer to make a 2.1 system with them. I do have two 8" subs installed in my desk, but i can't always play that coz it bothers the neighbors, so i want something smaller and lower power.

So i thought that it would be a good idea to use the TL494-based amp for these speakers, as it would be rather small and very efficient. It will be running bridged at 2 ohms (4 ohm speakers wired in parallel). I'm currently in the process of populating the second PCB, and then i have to build the bridging circuit before i can test the whole thing.

If it ends up good, i will share the PCB, but i will leave some part values out for people to experiment with. It's a simple circuit anyway, there are not too many variables. And also, maybe someone ends up with better values than i did.
__________________
"Audio grade" components simply means that they failed at a more critical job.
  Reply With Quote
Old 3rd January 2015, 04:21 PM   #7
Acca is offline Acca  Serbia
diyAudio Member
 
Acca's Avatar
 
Join Date: Nov 2011
Class D AMP using only TL494
Ill make new scheme, because I tried better one, it use lm393,because it can modulate 0-100% signal.
  Reply With Quote
Old 3rd January 2015, 09:01 PM   #8
Th3 uN1Qu3 is offline Th3 uN1Qu3  Romania
diyAudio Member
 
Join Date: Feb 2010
Location: Bucharest
Send a message via Yahoo to Th3 uN1Qu3
Not really. It suffers from most of the same limitations. Also, the TL494 can be clocked externally making multiple channels easier.

My bridge is currently working, but there is something wrong with the second board, it is distorting a bit. Likely it is due to the fact that i used just random transistors as i was short of one 2N3904 and one 2N3906. Checking it on the scope now.

The noise performance of the bridge is much better than the single-ended one. I clocked the second board from the first one, and since they are operating in antiphase, most of the garbage that gets in cancels itself out. If i can stop it from distorting it'll be perfect.
__________________
"Audio grade" components simply means that they failed at a more critical job.
  Reply With Quote
Old 5th January 2015, 02:30 AM   #9
Th3 uN1Qu3 is offline Th3 uN1Qu3  Romania
diyAudio Member
 
Join Date: Feb 2010
Location: Bucharest
Send a message via Yahoo to Th3 uN1Qu3
By the way, just throwing it out there: In most simple, hobbyist-level class-D audio circuits, 0-100% modulation is actually not a good idea. It is better to have for example 5-95%, or maybe 2-98%, if your drivers are behaving well.

I'll let you think of why. Then i will be back with the explanation.
__________________
"Audio grade" components simply means that they failed at a more critical job.
  Reply With Quote
Old 6th January 2015, 06:56 AM   #10
Acca is offline Acca  Serbia
diyAudio Member
 
Acca's Avatar
 
Join Date: Nov 2011
Class D AMP using only TL494
I have lot work about D class,and l see that is better with op than 494.l have good drivers and l not care about modulation.l dont use feedback,as it work better without it ( l check on scope too). When use same triangle osc,clocking is easy.
  Reply With Quote

Reply


Class D AMP using only TL494Hide 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
Class D amp using TL494 ledmania Class D 109 12th November 2014 10:26 AM


New To Site? Need Help?

All times are GMT. The time now is 11:32 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki