Irs2092 - 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 November 2009, 11:28 AM   #1
diyAudio Member
 
Join Date: Oct 2009
Thumbs down Irs2092

hello :
i am from china .my english is very poor
i made a class d amp with irs2092 .
now have a problem :the ira2092 ic can't start up .
attach file is irs2092 sch, please give me some advise !
Attached Files
File Type: pdf IRS2092PBF.pdf (94.7 KB, 413 views)
  Reply With Quote
Old 10th November 2009, 02:11 PM   #2
diyAudio Member
 
Join Date: Jan 2007
hello,
have solved the problem?
Please,refer to oc pin adjust.First desconnect the resistor that goes to -b,leaving only the one that connect to vref and see if the amplifier works.
Maybe you will have to find mosfets with less qg or adjust the oc protection to a very value.
  Reply With Quote
Old 11th November 2009, 10:49 AM   #3
diyAudio Member
 
Join Date: Oct 2009
Default irs2092

Quote:
Originally Posted by odnaizutra View Post
hello,
have solved the problem?
Please,refer to oc pin adjust.First desconnect the resistor that goes to -b,leaving only the one that connect to vref and see if the amplifier works.
Maybe you will have to find mosfets with less qg or adjust the oc protection to a very value.
  Reply With Quote
Old 11th November 2009, 11:01 AM   #4
diyAudio Member
 
Join Date: Oct 2009
Hi odnaizutra,thanks for you reply.
today,I had adjust the low side oc protection point
but the amp can't start up .
now the IC 2092's pin 5 voltage is 0v and 3v to bounce up and down.
the ic auto restart .
can you give me some advise ?
Excuse me for my poor english
  Reply With Quote
Old 11th November 2009, 11:41 AM   #5
diyAudio Member
 
Join Date: Jan 2007
sure,
this indicate that protection is activated for some reason.
First you will have to see if all voltages are ok , because there are some under voltage protections that can activate this lock.
check ,in relation to ground , if you have unless +5 volts an -5 volts at the front end of 2092.If you have less than 4,5 volts,ic protection activate.Then ,check if you have unless 11 volts,in relation to -b at vcc.
supposing all voltages are ok,try using mosfets with less qg,since this ic activates the protection if qg of mosfets are huge.Try irfb4019 or similar.
This ic is very sensitive to layout of pcb.Try to follow ir suggestion.
Pay attention to inductor caracteristics.Dont use any unkwon ferrite at inductor.Only type 2 is ok.Other option has to be carefully studied.You could send some pictures of pcb and the hole project.
  Reply With Quote
Old 12th November 2009, 11:21 AM   #6
diyAudio Member
 
Join Date: Oct 2009
Thank you very much!
According to your theory, I think most likely lies in pcb layout , I will layout the pcb again.(refer ir suggestion).
  Reply With Quote
Old 15th November 2009, 02:40 PM   #7
diyAudio Member
 
Join Date: Jan 2007
Dont forget,
the output fet qg has a lot of influence at the protection activation (just the way you said , like hiccup mode).Try a low qg fet
  Reply With Quote
Old 16th November 2009, 01:23 PM   #8
sphinx is offline sphinx  Canada
diyAudio Member
 
Join Date: Nov 2004
Location: Toronto, Ontario
Quote:
Originally Posted by odnaizutra View Post
Dont forget,
the output fet qg has a lot of influence at the protection activation (just the way you said , like hiccup mode).Try a low qg fet
How does qg influence protection activation? Isn't the OCP sensing the voltage across Rds-on?
__________________
too many projects...not enough time
  Reply With Quote
Old 16th November 2009, 03:27 PM   #9
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
It's Vds what is sensed, and it includes not only Rds-on drop but also the drop across drain and source lead inductances (4.5nH + 12.5nH respectively for TO-220) and layout inductances. During switching events, when current is rising (negative current falling during body diode reverse recovery), voltage drop on Ls+Ld may exceed 4V (it's proportional to current rise slope) resulting in false trigger if proper blanking is not applied.


When a MOSFET is turned on, Vds does not fall to just Rds-on drop instantaneously, there is a turn-on process with several parts. In the last portion of the process, Vds is already low, below 15V usually, and gate to drain ("miller" or "feedback") capacitance increases dramatically as Vds drops further (see datasheets). As a result, the last part of the turn on process is long, particularly for parts with high gate charges. In these circumstances, Vds sensing may trigger protections erratically if blanking time is not long enough.
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 17th November 2009, 12:19 AM   #10
sphinx is offline sphinx  Canada
diyAudio Member
 
Join Date: Nov 2004
Location: Toronto, Ontario
thanks Eva..clear and concise as usual..you should write a book someday
  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
Irs2092 luka Class D 50 15th July 2012 01:48 PM
Another amp with IRS2092 mag Class D 23 18th June 2010 07:25 PM
IRS2092 AMP help yaronshani Class D 3 29th January 2010 02:29 PM
IRS2092 help! yudi02 Class D 2 11th October 2009 03:30 AM


New To Site? Need Help?

All times are GMT. The time now is 10:08 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