LM3886 power consumption in idle/mute mode - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 12th August 2012, 05:51 AM   #1
soda74 is offline soda74  Germany
diyAudio Member
 
Join Date: Sep 2009
Default LM3886 power consumption in idle/mute mode

Hello together!
Since the forum and google search did help, here is my current issue:

I measure a power consumption of about 2.6W (mute on) and 2.7W (idle) for one LM3886 in my diy amp. The measurement includes the losses in the psu. The psu provides +/-25V=.

Is 2.7W a normal value?

Redards.
  Reply With Quote
Old 12th August 2012, 06:42 AM   #2
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
What does it say in the datasheet?
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 12th August 2012, 06:55 AM   #3
soda74 is offline soda74  Germany
diyAudio Member
 
Join Date: Sep 2009
The datasheet gives you all information about the maximum power consumption/output/dissipation an how to calculate the correct heatsink but it was no help (for me) to figure out the power consumption in idle/mute mode.
  Reply With Quote
Old 12th August 2012, 07:02 AM   #4
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Oh, okay, I must be mistaken. 2.6W does sound a tad on the high side, but I suspect most of that is in the PSU. Can you take a measurement of just the chip?
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 12th August 2012, 07:43 AM   #5
soda74 is offline soda74  Germany
diyAudio Member
 
Join Date: Sep 2009
Unfortunately it is not mainly the psu. The losses in the psu should be minimal compared to the consumption of the power stage.

The setup:
1x psu, 1x microcontroller+mixer, 1xpower-amp with 3xlm3886.

The measuements I already made:
- The psu+microcontroller-board alone: 6.85W
- All connected, mute on: 14.65W
- All connected, mute off: 15.0W
- All connected, mute disconnected*: 14,65W

*the mute is switched by the micro.

This results in approx. 2.6W-2.7W per lm3886.
The schematic is mainly the basic datasheet suggestion.

The ripple voltage of the psu is <=200mV (peak-peak) for the +rail and <=120mV for the -rail while playing music at low volume @+/-26V.
  Reply With Quote
Old 12th August 2012, 07:53 AM   #6
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Quote:
Originally Posted by soda74 View Post
Hello together!
Since the forum and google search did help, here is my current issue:

I measure a power consumption of about 2.6W (mute on) and 2.7W (idle) for one LM3886 in my diy amp. The measurement includes the losses in the psu. The psu provides +/-25V=.

Is 2.7W a normal value?

Redards.
Sounds very reasonable. 2.7watts and a 50 volt supply is around 54ma. The data sheet say 50ma as typical and 85ma as a max so its spot on.

Is that what you mean
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 12th August 2012, 08:06 AM   #7
soda74 is offline soda74  Germany
diyAudio Member
 
Join Date: Sep 2009
Thanks a lot!
Now I found it too, on page 4 electrical characteristics (what a surprise!):
I+ (Note 4) Total Quiescent Power Supply Current VCM = 0V, Vo = 0V, Io = 0A 50 85 mA (max)
I am sorry for that unnecessary thread! Sometimes you do not see the wood for the trees. :-/
  Reply With Quote
Old 12th August 2012, 08:07 AM   #8
Mooly is online now Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
No problem
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 12th August 2012, 09:10 AM   #9
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
I'm glad you found it. I had in my head 40mA, but wasn't certain enough to quote that.
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 12th August 2012, 12:15 PM   #10
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
That quiescent current stated in the specification is for normal no-signal operating condition.
I cannot see a specification value for current when in mute mode.
When I look at the mute circuit on p7, it appears that the mute only attenuates the gain of the input stages. It does not show any connections to the power stages. That's where the big current consumption will be. The earlier stages will probably be more like opamps in current consumption.
__________________
regards Andrew T.
  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
need LM1876 mute mode and standby mode help JozzaG Chip Amps 21 19th January 2012 05:28 PM
Idle power consumption noah katz Class D 7 31st October 2011 08:01 AM
lm3886 no mute rtill Chip Amps 21 29th August 2009 05:43 AM
LM3886, power caps, input resistors, mute, and Cm. mudihan Chip Amps 3 21st December 2007 09:23 AM
LM3886 Mute richie00boy Chip Amps 6 18th August 2004 11:26 AM


New To Site? Need Help?

All times are GMT. The time now is 06:53 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