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

Digital amplification
Digital amplification
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 23rd August 2005, 02:06 PM   #11
funberry is offline funberry  United States
diyAudio Member
 
Join Date: Aug 2005
Thanks
The Wolfson micro parts are awesome.
I will get one and experiment with it.

I am not a seasoned DSP programmer, and to implement this I would have to stick to the only one I have expecience with-- dsPIC from Microchip.

In worst case, I could indeed implement the PCM-to-PWM conversion in firmware. But I assumed a dedicated chip could do it better, faster, more accurately.

Think about it: if you have a 16 bit signal to convert to PWM-- that's 64,000 individual timing quanta. Superimpose that on a PWM base frequency of 50 KHz, and you'd need a 3200 MHz clock to resolve 16 bits in PWM.

I can't implement that in a DSP, unless I reduce something.

Reduce bandwidth: (for subwoofer) 100Hz passband, with 1KHz PWM carrier.

Reduce resolution, 12 bit instead of 16.

That's 4096 x 1000, or about 4MHz PWM timing clock. Although doable, this stretches the limit of a DSP, since you will need to execute more than 1 instruction per PWM step.

But then you have a PWM carrier in the audible range. A subwoofer channel will imply hefty class D amplification post-processing.
A class D amp operating at 1KHz! -- great; the MOSFETS will like it.
Unless the whole circuit is dunked in epoxy and cemented, there may be some audible whine coming out of that.

I'll try both approaches
thanks
  Reply With Quote
Old 24th August 2005, 09:59 AM   #12
i-s is offline i-s  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: UK
Quote:
I remember reading something like this at Zetex. Unfortunately I don't know the part number
ZXCW8100 and ZXCW6100
  Reply With Quote

Reply


Digital amplificationHide 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
Why not many PWM amplification(all digital) projects around here ? percy Digital Source 9 19th March 2008 01:22 AM
amplification? xstephanx Full Range 29 4th June 2006 05:58 PM
Help with tube amplification? SashaV Tubes / Valves 4 20th February 2006 04:04 AM
Onix Amplification Jack Colebourne Solid State 5 27th May 2005 07:04 AM
Amplification Howard Subwoofers 5 25th December 2004 07:03 AM


New To Site? Need Help?

All times are GMT. The time now is 12:31 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki