ucd 25 watts to 1200 watts using 2 mosfets - Page 10 - 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 3rd June 2010, 05:46 PM   #91
ejtagle is offline ejtagle  Argentina
diyAudio Member
 
Join Date: Nov 2005
Well... i was thinking if it would be worthwhile to try to answer or not to all the things that have been told about this amp. I was the designer of it, and, be sure, i know the limitations of the design. Severe compromises had to be done in order to make this design doable by common people.
Please, take into consideration that the design was severely affected by the semiconductors that are/were readily available on the local market, here in Argentina. Of course you can always buy fancy and more appropiate components from an international supplier, such as Digikey or Farnell, but that would make nearly impossible to hobbists to build it, just because it is extremely expensive and difficult to import electronic components in low quantities, at least, here.
The design lacks several features desirable for a commercial design, specially , all the required protections (short circuit, overvoltage, etc). It is also using old (but cheap and easiliy available) mosfets that are not "suitable" for class D audio. It even uses an IR211x mosfet driver, that "lacks" internal deadtime control, and requires a level shift translator (a discrete one).
And, i also agree that the board should be a double layer one with metallized holes, but, again, such board would put the design out of the possibilities of regular hobbists, because metallized holes on boards can't be done at home... And would require boards to be professionally made, rising costs again.
And , of couse, the inductor should be wound on a ferrite/metal powder core, but, again, it would mean amateur hobbists are left out of the design...
So...
Take this amp as a proof of concept, and NOT as a commercial design... It has room for lots of improvements (use more suitable mosfets, for example... add external deadtime control, redesign board as a double sided one, etc... But please, do not complain... I see none of you posting designs, all i see are people trying to get already designed and foolproof schematics that outperform, if possible, commercial designs with special components, and lots of time used to debug those designs...

Eduardo

PD: regarding the deadtime, the IR211x has non simmetric propagation delays (turn on is delayed more than turn off, so... it can be taken as internal delay... And the circuit features a basic R and diode in series with mosfet gates, to control it... So it is not fair to say no deadtime control was provided... AND i know the internal diode of this mosfet is slow... BUT, that's exactly one of the purposes of the R||D in gate network... To make the switching time a little bit slower, so we don't blow the internal diode in the process... Of course this rises the disspation of each mosfet, but allows to use slower and cheaper devices... So , lot of compromiese are here... You are free to change mosfets, if you need, so don't complain!)
  Reply With Quote
Old 3rd June 2010, 06:16 PM   #92
AP2 is offline AP2  Italy
Banned
 
Join Date: Dec 2009
Location: Italy
hi,
when amplifier is finished and working properly (or other amp that uses Ir21xx) then you can lower the THD especially in the low power segment, varying the R (high-side gate) to asymmetrical (lower value than at the low side gate).
This is due to an additional delay to the internal series IR21xx. (asymmetric DT)
e.g. High side=6,8R -low side=15R

Regards
  Reply With Quote
Old 4th June 2010, 03:13 PM   #93
diyAudio Member
 
Reactance's Avatar
 
Join Date: Jun 2005
Location: Cape Town
Quote:
Originally Posted by AP2 View Post
hi,
PD: regarding the deadtime, the IR211x has non simmetric propagation delays (turn on is delayed more than turn off, so... it can be taken as internal delay... And the circuit features a basic R and diode in series with mosfet gates, to control it... So it is not fair to say no deadtime control was provided... AND i know the internal diode of this mosfet is slow... BUT, that's exactly one of the purposes of the R||D in gate network...

Regards
This was my point exactly ! the driver ic already has internal DT which i know eva has already spoken about in previous designs IR2011 ECT..,why put another DT branch in the circuit unless your specification alters the design but i trust the design as a proof of concept it a great (tutorial) !

When i get some time im going to build this and improve it where i see fit there are already many sub system protection circuits on this site that can slot in with a few mods here and there, especially on the power supply forum, tailored to ones needs.(simple)

I personally feel there are some jealous people on the forum that are deliberately posting negative viewpoints for those of you who are considering to post more negative posts..do this give us / newbies your example i mean a living example instead of text descriptions of your pro designs which is meaningless for newbies that learn from living examples.
__________________
There’s nothing worse than the smell of burned output transistors!!

Last edited by Reactance; 4th June 2010 at 03:24 PM.
  Reply With Quote
Old 4th June 2010, 06:53 PM   #94
AP2 is offline AP2  Italy
Banned
 
Join Date: Dec 2009
Location: Italy
Quote:
Originally Posted by Reactance View Post
This was my point exactly ! the driver ic already has internal DT which i know eva has already spoken about in previous designs IR2011 ECT..,why put another DT branch in the circuit unless your specification alters the design but i trust the design as a proof of concept it a great (tutorial) !

When i get some time im going to build this and improve it where i see fit there are already many sub system protection circuits on this site that can slot in with a few mods here and there, especially on the power supply forum, tailored to ones needs.(simple)

I personally feel there are some jealous people on the forum that are deliberately posting negative viewpoints for those of you who are considering to post more negative posts..do this give us / newbies your example i mean a living example instead of text descriptions of your pro designs which is meaningless for newbies that learn from living examples.
Hi,
Because You know internal IR21xx,then I can not explain async DT?

yes some jealus people attak me, ......you instead?

other bla,bla I not understand,sorry.
If you want a complete description,scheme and examples,please chose arguments and I help diy.

Regards
  Reply With Quote
Old 6th June 2010, 02:34 PM   #95
opor is offline opor  Thailand
diyAudio Member
 
Join Date: Nov 2005
Hi All,
I have just finished this amp. It works. But I have some question. I connected 20KA volume before the input .When it is in min. and max. postion there is some noise as normall but when it is in any position between min. and max. ,there is an oscillation noise. Why?
I replaced D2 UF4004 with MUR120 , increased C2 and C8 to 470pf ,decreas R5 and R13 to 10 ohm .
  Reply With Quote
Old 6th June 2010, 02:36 PM   #96
opor is offline opor  Thailand
diyAudio Member
 
Join Date: Nov 2005
And replaced D1 and D3 ,1N5817 with 1N5819.
  Reply With Quote
Old 6th June 2010, 03:45 PM   #97
diyAudio Member
 
andrewlebon's Avatar
 
Join Date: Feb 2008
hi opor
greetings good news amplifier is working how is the output sounding
any tips on your construction and powering up procedure how many turns
on output coil
thanking you
andrew lebon
  Reply With Quote
Old 6th June 2010, 03:52 PM   #98
savu is offline savu  Romania
diyAudio Member
 
savu's Avatar
 
Join Date: Feb 2007
Location: Cluj - Napoca
Send a message via MSN to savu Send a message via Yahoo to savu
Greetings all who have succeeded ...

Do you have output scope diagrams and so on to share ?

best regards,

Savu Silviu
__________________
1'st rule of chess:
The only way to get smarter is by playing a smarter opponent.
  Reply With Quote
Old 6th June 2010, 04:00 PM   #99
opor is offline opor  Thailand
diyAudio Member
 
Join Date: Nov 2005
Sound is great. But as I said I still have only one problem about adding 20KA volume at the input. My inductor is not good enough so it is a little hot. But I am happy with this design. One only thing is to get rid of an oscillation.
  Reply With Quote
Old 6th June 2010, 04:06 PM   #100
diyAudio Member
 
andrewlebon's Avatar
 
Join Date: Feb 2008
hi opor
greetings sorry for troubling you is it really that powerful
any pictures of amplifier what voltage rails are you using
thanking you
andrew lebon
  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
Philips 40/25/15 watts amplifier with Universal preamplifier circuit. renjiish Solid State 64 28th July 2014 11:33 AM
Decibel Watts VS Watts ? fivestring Solid State 11 1st April 2009 01:08 PM
AMP1-B: why only 25 watts @8ohms? theAnonymous1 Class D 10 15th August 2005 06:55 PM
Sound quality of amps at 0.3 watts vs @ typical 5 watts rick57 Solid State 2 26th March 2005 06:25 AM
Need 2 watts Vivek Everything Else 4 17th July 2003 08:29 AM


New To Site? Need Help?

All times are GMT. The time now is 01:03 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