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

Big-t
Big-t
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 11th January 2008, 09:13 AM   #81
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
Primary waveform looks rather strange. Is your chasis AC (or DC) coupled to ground? Also, secondary waveform reveals that you are not waiting for complete resonance before turning on the opposite side.

BTW: Yesterday I toasted a 3KW power factor corrector prototype (80-280V AC input, 415V DC output) because I soldered one end of a jumper to the wrong place. This is prone to fireworks
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 11th January 2008, 09:30 AM   #82
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Big-t
Hi

Was diode only thing that was destroyed?

"safety bulb in series with the supply glowed"
where and what type did you have?
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th January 2008, 09:37 AM   #83
djQUAN is offline djQUAN  Philippines
diyAudio Member
 
Join Date: May 2004
Location: manila
Send a message via MSN to djQUAN Send a message via Yahoo to djQUAN
the chassis is connected directly to ground right at the input terminals via #14 wire. board ground is connected to terminal via two 8ga wires.

tripath module ground is also directly connected to ground.

the first waveform pic is the waveform right at the mosfet gate.

second pic is right at the primary (mosfet drain)

third is after the half bridge of the T amp

luka,
I'm using a headlight bulb with both high and low beam in parallel. the whole thing is connected between car battery + and amp input.

nothing was toasted. the diode seems to be still functional. just a black mark on the heatsink and chassis.
  Reply With Quote
Old 11th January 2008, 09:47 AM   #84
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Big-t
Hi

Ahh ok thats good, good diode This time clean chassis of all "can't be there" stuff
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th January 2008, 09:49 AM   #85
djQUAN is offline djQUAN  Philippines
diyAudio Member
 
Join Date: May 2004
Location: manila
Send a message via MSN to djQUAN Send a message via Yahoo to djQUAN
here are some secondary waveforms:

first trafo secondary:
Click the image to open in full size.

second trafo secondary:
Click the image to open in full size.

second trafo waveform X10 mag:
Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 11th January 2008, 09:50 AM   #86
djQUAN is offline djQUAN  Philippines
diyAudio Member
 
Join Date: May 2004
Location: manila
Send a message via MSN to djQUAN Send a message via Yahoo to djQUAN
Quote:
Originally posted by luka
Hi

Ahh ok thats good, good diode This time clean chassis of all "can't be there" stuff

I just stumbled upon my diode somewhere....it's rated at 75A 1200V
  Reply With Quote
Old 11th January 2008, 09:59 AM   #87
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Big-t
Hi

loool, hope you won't use it?? What is its forward voltage drop + is it even fast?
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th January 2008, 10:02 AM   #88
djQUAN is offline djQUAN  Philippines
diyAudio Member
 
Join Date: May 2004
Location: manila
Send a message via MSN to djQUAN Send a message via Yahoo to djQUAN
that's what I'm using here right now.

it's fast recovery. voltage drop in the diode test using DMM is about 300mV.

another note: transformers stay cold.

output inductors get perceptively warm. that's barely warm. residual at speaker outputs is rather high though at 3Vpk (a clean sine wave at the osc freq of the tripath chip) which has always been there even when I first built it.
  Reply With Quote
Old 11th January 2008, 11:41 AM   #89
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
I told you the PSU was overkill. You can power two or three class D modules with it, maybe four

Also, you don't need litz style wire on class D output toroid inductors. It should have taken quite a lot of time and effort to wind them that way
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 11th January 2008, 12:26 PM   #90
djQUAN is offline djQUAN  Philippines
diyAudio Member
 
Join Date: May 2004
Location: manila
Send a message via MSN to djQUAN Send a message via Yahoo to djQUAN
I was future-proofing the supply. so when I get a bigger amplifier module, no need to make another supply.

alas, this thing just caught on fire!

well, sort of. I was having weird waveforms at the output when moderately loaded so I adjusted the freq and increased it a bit.

the waveform was a normal square wave but has a huge 40v peak with flat tops during deadtime so I thought "hey, let's increase the freq!" so I did and it worked fine for a couple of minutes then the diodes (1N4937) at the primaries (for voltage doubling for the gate supply) smoked and I have a few delaminated copper foil and four dead diodes. haven't checked for any other damages but it blew the 60A fuse at the power input so something must have also blown.

btw, I have lots of litz wire. it also makes winding the coils easy as they are easier to bend.
  Reply With Quote

Reply


Big-tHide 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


New To Site? Need Help?

All times are GMT. The time now is 10:58 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki