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 input LM311 Inverting input
Class D input LM311 Inverting input
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 31st January 2008, 08:35 PM   #1
zox2003 is offline zox2003  United States
diyAudio Member
Join Date: Nov 2004
Location: usa
Default Class D input LM311 Inverting input

I attached schematic of class D Amplifier.Inverting input of LM311 is connected to GND thru 2K resistor.Non-inverting pin is referencing 11K to GND.What is going on with offset in this case?
I have seen a lot of construction like this.Aren't we supposed to have capacitor in series with that 2K resistor?Maybe I am wrong...

Attached Files
File Type: pdf amp.pdf.pdf (9.5 KB, 500 views)
  Reply With Quote
Old 1st February 2008, 08:48 AM   #2
Eva is offline Eva  Spain
diyAudio Member
Eva's Avatar
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Offset in class D comes both from modulator DC errors and from timing errors. In self oscillating class D you can get rid of the comparator DC error by wiring it in a differential fashion. Then only the DC offset due to asymetric delay remains.

This schematic is not particularly good in that respect, as one input sees 10k at DC and 5n at HF, and the other sees 2k at DC plus 2k in series with 470p at HF.
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote


Class D input LM311 Inverting inputHide 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
opamp inverting input sounds better? dorkus Solid State 112 19th November 2014 07:23 PM
Inverting opamp input resistors calculation (pic) redrabbit Parts 3 18th July 2007 10:12 AM
Aleph-phase lag with non-inverting input jupiterjune Pass Labs 38 21st February 2007 05:05 PM
Input impedance of a non-inverting op amp? glennb Chip Amps 24 21st May 2004 04:24 AM
Input impedence of inverting gainclone PHilgeman Chip Amps 1 7th January 2004 04:33 PM

New To Site? Need Help?

All times are GMT. The time now is 11:43 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