Will This Work? - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 25th December 2005, 04:40 PM   #1
diyAudio Member
 
sousmielie's Avatar
 
Join Date: May 2005
Location: GP (Gangstas Paradise)
Default Will This Work?

Hi,

Merry Xmas to all!

Will this circuit work? I drew it about a month ago, and would like any sugestions/comments before I start building it. The switching freq is around 250kHz. I'm planning on using a LM319 for the comparator and TL082CP for the osc.

Sorry for the badly drawn schem.

Thanx alot

Regards,

Werner
Attached Images
File Type: jpg classd.jpg (51.9 KB, 412 views)
  Reply With Quote
Old 25th December 2005, 08:04 PM   #2
bob123 is offline bob123  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Southampton UK
well it would work. But the sound qualtiy would be POOR, also there would be some power loss due to the lack of a dead time circuit. You need a resistor and a diode before the mosfet stage to prevent both being on at the same time.

What is the chip in there as i can read it from the schematic.

You could also use some feedback from the output stage back to the comparitor as it would prevent the destortion of the mosfets.

The inductance is a bit high for a 250k switching frequency, should be more like 60uH. The capacitor value is also a bit low.

But with some adjustments the circuit is a worker.

Rob
  Reply With Quote
Old 25th December 2005, 08:12 PM   #3
Pierre is offline Pierre  France
Banned
 
Join Date: Nov 2004
Location: Paris
Sorry but it won't work at all.
You need level shifting between the output of your comparator, that swings between 0 and +6V (or -6V and +6V if you use an opamp), and the input of the IR2111, whose supply should be referred to -56V.

You can find lots of similar schematics in the forum, one of them for example in the "help! turn on big current" or similar. It doesn't work correctly yet but you can find how to connect the level shifter(s).

If you need it for full-range, you have to lower the inductance of the filter to, say, 20-40uH.
  Reply With Quote
Old 25th December 2005, 08:28 PM   #4
bob123 is offline bob123  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Southampton UK
yes that is true i didnt spot voltage level, You need a voltage amplifier in there to alow an ouput of more than +-6V. I suggest a biased transitor/ mosfet voltage amplifier amplifier.
  Reply With Quote
Old 26th December 2005, 06:36 AM   #5
Pierre is offline Pierre  France
Banned
 
Join Date: Nov 2004
Location: Paris
Sorry, bob, but that's not what he needs.
He needs a voltage level shifter. It can be solved with a single PNP transistor and a couple of resistors.

Best regards
  Reply With Quote
Old 26th December 2005, 09:48 PM   #6
Account Disabled
 
Join Date: Feb 2004
Send a message via AIM to classd4sure Send a message via MSN to classd4sure
Hi Werner,

Give LTspice a try, it's free, do the tutorials it comes with/read the help section get the basics of it figured out and then try a few ultra simple circuits of your own in it... within no time at all you'll be able to let your imagination run wild with it, much better than pencil and paper.

Best,
Chris
  Reply With Quote
Old 27th December 2005, 05:53 PM   #7
diyAudio Member
 
sousmielie's Avatar
 
Join Date: May 2005
Location: GP (Gangstas Paradise)
Hi, Thanx

Sorry, forgot to draw the diode infront of the mosfets, the ones in parallel with the gate resistors.

As for the level shifter, I now have a circuit, that uses a PNP transistor, I took that part from some old ClassD car amp, which used the IR2011 or something like that.

I'll be working more on the circuit, as soon as I have FORMATTED my machine, for a strange reason my XP64 is getting slower than my grannies 700MHz Celeron!

Thanx alot,

Cheers,
Werner
  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
TL and JBL could it work Flodstroem Multi-Way 47 14th July 2006 03:03 AM
Would this work ? LesPaulStandard Instruments and Amps 3 4th May 2006 02:14 AM
It Should Not Work ! f4bok Solid State 3 6th September 2004 05:33 PM
Would this work? JoeBob Solid State 5 18th July 2003 03:40 PM


New To Site? Need Help?

All times are GMT. The time now is 01:21 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