500W amplifier using IRS20955 and IRFB4227 - Page 2 - 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 11th May 2011, 05:24 PM   #11
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Send a message via Skype™ to luka
I use zxgd3002e6, my output stage is nothing diffrent then it would be without buffers, just that IRS drives buffers and buffers drive fets.. buffers are the for faster turning on fets, better waveforms
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th May 2011, 05:34 PM   #12
diyAudio Member
 
Join Date: Dec 2008
Quote:
Originally Posted by luka View Post
I use zxgd3002e6, my output stage is nothing diffrent then it would be without buffers, just that IRS drives buffers and buffers drive fets.. buffers are the for faster turning on fets, better waveforms
Thanks , very nice

what resistor do you use from totem driver to mosfet ?, I presume from totem driver to mosfet shotkey diode is not needed

Also what about bootstrap : now both irs chip and this driver have to have external bootstrap cap, right? or we can tie together totem driver Vcc pin and irs Vb pin ?
  Reply With Quote
Old 11th May 2011, 05:40 PM   #13
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Send a message via Skype™ to luka
for gate resistor I used 10r and 1n4448 you don't need more
For bootstrap I use 47uF (upper one) for IRS, and something like that for buffer, which is SMD as is this capacitor, so yes, both have external cap. you could use only one from IRS, but this is like 0.5mm from the buffer, so that is the best I could do

(everything is charged from lower side)
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th May 2011, 05:50 PM   #14
diyAudio Member
 
Join Date: Dec 2008
Quote:
Originally Posted by luka View Post
for gate resistor I used 10r and 1n4448 you don't need more
For bootstrap I use 47uF (upper one) for IRS, and something like that for buffer, which is SMD as is this capacitor, so yes, both have external cap. you could use only one from IRS, but this is like 0.5mm from the buffer, so that is the best I could do

(everything is charged from lower side)
ok

What is optiaml totem driver to mosfet resistor ? now maybe something like 1-2 ohm would be optimal, cause it will increase speed of large gate charge mosfets

I wonder why people usually use High-low side mosfet driver(ir2110) for "big mosfets"(read high current big gate charge ones), instead this driver + totem pole ?, This seems much better, irs20957 has nice protection logic
Usually all newer power mosfets have less than 10nF gate

This way there is practicly no limit to gate charge when we have 9A mosfet driver, right?!

Last edited by grizlimedo; 11th May 2011 at 05:53 PM.
  Reply With Quote
Old 11th May 2011, 05:55 PM   #15
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Send a message via Skype™ to luka
why? coz they know it, and/or can only get them... but even 2110 is getting old now
and also fets are, if you get them, 10000x better then what most people use, those big irfp250's or such

well if you look at when you get 9A, you will see that won't happen, unless you will put 1A into driver itself... while you can get over 2A with just 10ma!
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th May 2011, 06:12 PM   #16
diyAudio Member
 
Join Date: Dec 2008
Quote:
Originally Posted by luka View Post
why? coz they know it, and/or can only get them... but even 2110 is getting old now
and also fets are, if you get them, 10000x better then what most people use, those big irfp250's or such

well if you look at when you get 9A, you will see that won't happen, unless you will put 1A into driver itself... while you can get over 2A with just 10ma!
Yes, you are right

But you get 5A with 100mA imput, graph is exponential (in datasheet)
2A with 10mA
9A with 1A


i had to order irs chip from "farnell" and wait them for 1 month to come from USA

I ordered 6 pcd, I hope i Will not burn them all before I make it work, soon Ill post schematics related to irs20957 driver ad mosfets for inspection (just to be safe)

One thing that I am concerned most will comparator work if positve electrode is to gnd and negative is audio + feedback (never seen practical design with suck setup) , but spice show less thd..
  Reply With Quote
Old 11th May 2011, 08:41 PM   #17
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
Quote:
Originally Posted by grizlimedo View Post
Why then rating this "1A" mosfet driver? Such driver should be able to drive much higher gate charge. The only drawback I see is heat dissipation limit on irs chip, ?!
I use the irs2092 with a single pair of 4227's and have no problems.
The 2092 gets a little warm but nothing to worry about.
  Reply With Quote
Old 11th May 2011, 08:47 PM   #18
diyAudio Member
 
Join Date: Dec 2008
INTERNATIONAL RECTIFIER|IRFB4020PBF|MOSFET, N, 200V, TO-220AB | Farnell United Kingdom


What about irfb4020, double the irfi4020 current rating and gate charge is the same, also power dissipation is much higher?
I wonder what is maximum power rating with half bridge with 18A mosfet ?
lets say we go on safe side, i think this should work up to 500W 4 ohm ?

My goal is to make 4-8 ohm ampplifier, cause ucd has excellent filter control, and exact load impedance does not matter:

+/-70V and irfb4020 vs irfi4020 , latter one may not work above 250W 4 ohm cause too low current rating (official irf paper)


so far irfb4020 without totem pole seems the simplest solution .

Last edited by grizlimedo; 11th May 2011 at 08:51 PM.
  Reply With Quote
Old 12th May 2011, 06:33 AM   #19
diyAudio Member
 
darkfenriz's Avatar
 
Join Date: Jun 2004
Location: Warsaw
Rds-on is still a bit high.
  Reply With Quote
Old 12th May 2011, 10:41 AM   #20
diyAudio Member
 
Join Date: Dec 2008
Quote:
Originally Posted by darkfenriz View Post
Rds-on is still a bit high.
If I am correct, , 500W around 15A, and 25W dissipation caused by Rds (on),

could work with good cooler, but, what about paralleling two mosfets in half bridge ? can that work? half bridge with 4 mosfets than only 5W per mosfet. Usually mosfets can be paralleled cause positive temperature coefficient without any resistors

Last edited by grizlimedo; 12th May 2011 at 11:07 AM.
  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
500w power amplifier juneray Solid State 70 16th September 2011 04:05 PM
500W Power Amplifier JRdGreat Solid State 24 16th September 2009 09:48 AM
schematic for IRS20955 iwan_audio Class D 0 7th April 2008 06:29 AM
Looking for 300-500W amplifier audioPT Solid State 3 31st August 2002 12:39 PM


New To Site? Need Help?

All times are GMT. The time now is 03:32 PM.


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