Class D amplifier help - 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 7th July 2009, 09:50 PM   #1
diyAudio Member
 
Join Date: Jul 2009
Default Class D amplifier help

Hi all,

I am building a class D audio amplifier using the following parts:

LM311 - comparator
IR2010 - gate driver for the mosfet pair

This is the data sheet for the IR2010
http://www.irf.com/product-info/data...ata/ir2010.pdf

I am unsure what the input for the IR2010 would be..

Thanks
  Reply With Quote
Old 7th July 2009, 09:54 PM   #2
diyAudio Moderator Emeritus
 
Iain McNeill's Avatar
 
Join Date: Oct 2007
Location: Santa Cruz, California
Do you have a schematic?

The 2010 is basically just a level shifter so you can switch the gate of the high side FET.

How are you generating the 2 PWM streams?
  Reply With Quote
Old 7th July 2009, 11:21 PM   #3
diyAudio Member
 
Join Date: Jul 2009
as i can see from the data sheet, there are 2 inputs - LIN , HIN for the IR2010. However, I just have one pwm stream. I am generating this stream by comparing my input signal (i.e. audio) with a saw-tooth waveform using the LM311 comparator chip.

I did not know that there were 2 PWM inputs required... how do I get the second PWM input and why is it required.
  Reply With Quote
Old 7th July 2009, 11:43 PM   #4
diyAudio Moderator Emeritus
 
Iain McNeill's Avatar
 
Join Date: Oct 2007
Location: Santa Cruz, California
usually, there's a dead time at each transition so that the on FET turns off before the off FET turns on. It takes longer to turn the on FET off than the off FET on. This means that at low level (input to driver) the PWM stream is almost identical except for dead time gaps.

Hence upper stream is different from lower stream.

Oh, and the high side is inverted. Does the driver do that for you?
  Reply With Quote
Old 8th July 2009, 02:54 AM   #5
diyAudio Member
 
Join Date: Jul 2009
hmmm .. thats interesting .. i was not aware of this ..

how would i generate the other PWM stream (with the dead times)?

I noticed that some comparators like the LM361 yield two outputs... so if i decide to switch my comparator from the LM311 to the LM361 can I just feed in one of the outputs into the HIN and the other into the LIN without actually having to generate another PWM stream?
  Reply With Quote
Old 8th July 2009, 03:29 AM   #6
diyAudio Member
 
Join Date: Apr 2006
Location: Minnesota
yellow,

Given your questions you need to do your homework on Class D, before you try to build anything.

Rick
  Reply With Quote
Old 8th July 2009, 04:03 AM   #7
diyAudio Moderator Emeritus
 
Iain McNeill's Avatar
 
Join Date: Oct 2007
Location: Santa Cruz, California
Yes, read a book or two.

Can anyone recommend an authoritative text?

I'd be interested myself.
  Reply With Quote
Old 8th July 2009, 08:35 AM   #8
diyAudio Member
 
darkfenriz's Avatar
 
Join Date: Jun 2004
Location: Warsaw
One of possible solution for dead time generator and symmetrizer with some intentional time delay.
Input at transistor's base, 2 complementary outputs with adjustable dead time.
http://www.diyaudio.com/forums/attac...amp=1208267656

P.S. There are gate drivers with just one PWM input, like IR2104, but for class D amplifier you should have much lower dead time, possibly adjustable.
  Reply With Quote
Old 8th July 2009, 02:21 PM   #9
diyAudio Member
 
Join Date: Jul 2009
Yeah I will refer to books.

I am an EE undergrad student and took this project upon myself for educational purposes. My goal is to get a functional class D amplifier and in the process realize how the various components work with each other.
  Reply With Quote
Old 8th July 2009, 02:33 PM   #10
diyAudio Member
 
Join Date: Apr 2006
Location: Minnesota
I don't know of a good book, but you should look for application notes from companies that make class D control ICs.
  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
Class D Vs Class I (Balanced Current Amplifier) rmsaudio Class D 29 26th January 2014 10:25 PM
Class A Amplifier Jean-Paul_2 Solid State 22 21st June 2009 02:36 PM
Questions about how to decrease the PASS A-40 amplifier into a class AB amplifier. novtango Pass Labs 2 21st October 2002 01:50 AM


New To Site? Need Help?

All times are GMT. The time now is 01:33 PM.


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