SMPS overload protection specs - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 17th April 2015, 12:11 PM   #1
chongwl is offline chongwl  United States
diyAudio Member
 
Join Date: Apr 2015
Default SMPS overload protection specs

Hi, I'm trying to understand overload protection specs on switching power supplies.

I often see "105% - 150% rated power. Automatic recovery."
  1. Does that mean a 36V, 4.17A, 150W PSU can deliver 150*150% = 225W peak power?
  2. How does this overload relate to over-voltage protection? Does it deliver 225W through higher current (36V, 6.25A) or higher voltage?
  3. Is there a standard time for how long it can deliver peak power before going into protected mode?
  4. What does the lower number (105%) mean?

Thank you!
  Reply With Quote
Old Yesterday, 09:59 PM   #2
infinia is offline infinia  United States
diyAudio Member
 
infinia's Avatar
 
Join Date: May 2005
Location: Californication
it's simply a tolerance of the current limit, usually sensed on the primary.

practically speaking the target trigger point being set @ ~ 128 % rated power. wider range is for manufacturing tolerances and reference temperature drift combined.
1) peak power within the range given, once CL is triggered it's gone into "protect mode".
2) it doesn't! it regulates voltage until CL is triggered.
3) its a set point, u can only count on 5% 'bonus' power. practically it'll be closer to 128% or 5.3A peak. time isn't spec'd but it's very small like beyond the SMPS loop bandwidth, faster over current peaks supported are related to output capacitance and any local decoupling placed near your dynamic loads. note> Often you cant simply add more C to the outputs to provide higher current as it reduces the loop bandwidth and may cause unstable regulation.
4) lower spec limit on CL set point.
__________________
like four million tons of hydrogen exploding on the sun
like the whisper of the termites building castles in the dust

Last edited by infinia; Yesterday at 10:24 PM.
  Reply With Quote
Old Today, 08:59 AM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
This is one area where I have tried to understand what an SMPS is capable of doing, as it relates to the very varied current demands of a Power Amplifier.
The vast majority of Power Amplifiers draw a variable current from the supply.
If the amplifier were a 150W into 4ohms type fed from this 150W supply, then one would expect on normal music/audio signals to draw between 0amps and 8.66Apk when feeding a resistive test load.
Will an SMPS be able to deliver that 8.66Apk to the 4r0 dummy load?
Can one design the SMPS to meet that transient demand and still not overheat when the average currents are well within the 4.17A specification?

Note that in the above that two 150W SMPS are needed to supply the 150W amplifier. The average current draw from each SMPS is ~3.06Arms
__________________
regards Andrew T.

Last edited by AndrewT; Today at 09:03 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
TDA7264 overload protection? thetube0a3 Chip Amps 2 10th August 2012 12:37 AM
Overload / Short Circuit Protection, Yet Again... Buckeye Solid State 44 16th February 2011 03:52 PM
Overload and Short Circuit Protection space2000 Solid State 17 5th March 2009 10:26 PM
speaker protection (OR) overload protection myanmar Solid State 7 13th July 2006 08:21 AM
Subwoofer overload protection? Axeman Subwoofers 24 5th September 2003 04:44 PM


New To Site? Need Help?

All times are GMT. The time now is 03:06 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2