I need to drop about 5 Volt in an elegant manner - 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 20th January 2012, 07:08 AM   #1
diyAudio Member
 
Join Date: Sep 2009
Location: Timisoara
Default I need to drop about 5 Volt in an elegant manner

I have a 45Volt DC power supply but i need to drop this to about 40 Volt in order to power a LED driver. The maximum current i assume that will be drawn is somewhere around 100mA. My PCB is 12mm wide and 100mm long. MAximum component hight is 10mm.
  Reply With Quote
Old 20th January 2012, 07:26 AM   #2
diyAudio Member
 
sofaspud's Avatar
 
Join Date: Nov 2005
Location: San Antonio
LM317LZ, or a 5 volt 1 watt zener diode
__________________
It is error only, and not truth, that shrinks from enquiry. - Thomas Paine
  Reply With Quote
Old 20th January 2012, 08:52 AM   #3
diyAudio Member
 
Join Date: Sep 2009
Location: Timisoara
The series zenner should work fine. Thanks. Somehow it slipped my mind, i was thinking of parallel zenner only.
Does the LM317 work at these voltages ?
  Reply With Quote
Old 20th January 2012, 08:59 AM   #4
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Zener or 317 will work safely only if your driver has no input bypass.
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 20th January 2012, 09:07 AM   #5
diyAudio Member
 
astankov's Avatar
 
Join Date: Dec 2009
Location: Pernik
Here is my suggestion.

Regards!
Attached Images
File Type: jpg screenshot.1.jpg (158.6 KB, 371 views)
  Reply With Quote
Old 20th January 2012, 09:24 AM   #6
diyAudio Member
 
Join Date: Sep 2009
Location: Timisoara
The driver is TLE4242. What do you mean by input bypass ?
  Reply With Quote
Old 20th January 2012, 10:39 AM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I'll give my vote to a Zener.
__________________
regards Andrew T.
  Reply With Quote
Old 20th January 2012, 11:04 AM   #8
diyAudio Member
 
Join Date: Jul 2003
Location: Dona paula, Goa
LM317 input to output voltage difference allowed is 35 volts maximum. If there is input bypass, which means if there r any capacitors across the supply of the driver(which is quite possible), they will short the output for a very short time. This condition will drop more than 35 volts across the 317 and will become RIP.

On a second thought, why not use a resistor.

Gajanan Phadte

Last edited by gmphadte; 20th January 2012 at 11:08 AM. Reason: added content
  Reply With Quote
Old 20th January 2012, 11:14 AM   #9
diyAudio Member
 
Join Date: Sep 2009
Location: Timisoara
Thank you all for your suggestions.
I think i will try astankov's circuit first. Thanks a lot.
As for the input capacitor bypass, it is obvious a small cap is needed.
  Reply With Quote
Old 20th January 2012, 12:25 PM   #10
diyAudio Member
 
KatieandDad's Avatar
 
Join Date: Nov 2011
Location: UK
If you haven't got a 5V zener just use 7 diodes in series.
  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
12 volt to 300 volt inverter question for tubes yourownfree Tubes / Valves 93 30th March 2014 04:41 PM
What is the elegant way to convert 220? to 110V? Jay Power Supplies 13 9th December 2010 08:12 AM
Beautiful and elegant concept design neil_kaye Analogue Source 3 2nd July 2009 07:32 AM
Switching 230 Volt Transformer to 120 Volt OMNIFEX Parts 10 6th April 2008 05:34 PM
12 volt DC to 9 volt AC eRiCdWoNg Parts 10 18th April 2004 02:52 PM


New To Site? Need Help?

All times are GMT. The time now is 09:36 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