New to Class D - 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 22nd July 2009, 02:25 PM   #1
diyAudio Member
 
Join Date: Aug 2008
Default New to Class D

Good morning all,

I'm new to class D. From what I've read so far, it sounds very interesting. I don't have any class D amplifier experience, but I do have a background in electronics so I'm hoping that might be enough to get my by on my first project. Hopefully! :P

Of particular interest to me would be a very high powered mono subwoofer amplifier. I love playing around with bigger and bigger subwoofers, however when it comes time to drive them I'm out of luck. Class D's elegant means of modulating the power supply rails lends itself well to a brute force design such as this! I have lots to learn, which means lots of questions! If anyone would like to share an opinion or suggestion, please feel free.

One question I have has to do with scale-ability. Can I take a 100 watt design and use it to modulate 1000 watts? Take the National Semiconductor LM4651 (now obsolete, but you get the idea). It's a class D driver IC, intended to be connected to an external H-bridge mosfet array.

http://www.national.com/ds/LM/LM4651.pdf

Could I extract more power out of such a design by applying more voltage to the VCC and VEE of the mosfets, than what is applied to the LM4651? I'm assuming there is some kind of feedback path that is based on the assumption that these voltages are equal. Could I fool the LM4651 into thinking the mosfets are seeing the same supply voltages through use of a voltage divider network in the feedback path?

Also, can mosfets be ganged together somehow to increase their total current capability? Gate current is theoretically zero, so I wouldn't imagine it would be a big deal for the LM4651 to 'drive' more mosfets. However differences in Vgs while the mosfets are on may cause issues.

Finally, can you recommend any exceptional driver IC's, or power supply designs?

Thanks for looking!

JF
  Reply With Quote
Old 22nd July 2009, 03:15 PM   #2
diyAudio Member
 
Join Date: Aug 2008
Woops: I just saw the Class D Design Issues thread. I'll read up!
  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
1500W RMS Class D PCB - which Class D Driver Chip is it ? mosfetsound Class D 11 1st April 2011 12:17 PM
Can a Class AB PP amp be said to be operating in Class A at low signal levels? ray_moth Tubes / Valves 19 23rd January 2009 08:52 PM
How about a round-up of Class A kit power amps, or collectable vintage class A? Brisso57 Solid State 4 14th February 2007 11:30 AM


New To Site? Need Help?

All times are GMT. The time now is 04:58 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