Ultra-low forward voltage Schottky-rectifier - Page 2 - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

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 25th July 2008, 10:24 AM   #11
MRupp is offline MRupp  Germany
diyAudio Member
 
MRupp's Avatar
 
Join Date: Dec 2003
Location: Frankfurt area
Quote:
Read the first post carefully and try again
I must admit that I usually fly over most (though not all) posts, including yours.

Having said that, if I look at the datasheets that I have at hand and compare diodes of the same rating (ok, my shottkys are dual devices) the shottkys have invariably a much lower forward voltage drop than the standard diodes.

Example Ixys DSEP 15-03A (15 A, 300 V) VF _ IF = 15 A: TVJ = 150C 1.21V, TVJ = 25C 1.68 V

IR 16CTQ100 (16Amp, 100V) VFM Max. Forward Voltage Drop 0.72 V @ 8A (Per Leg) at TJ = 25 C 0.58 V @ 8A (0.69 V @ 16A) TJ = 125 C

The datasheets have diagrams with the related curves, and it becomes even more apparent. Same with other packages / higher current ratings, e.g. IR 40CPQ100 against various 30A diodes.
__________________
Martin Rupp
  Reply With Quote
Old 25th July 2008, 10:52 AM   #12
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Thanks for the reference to the IR-schottky!

I'm not a diode guru, I have to admit that I randomly picked a cheap Schottky diode with comparable ratings from the Digikey-catalogue and it didn't perform that well.

So the IR 16CTQ100 is 0.72 V at 25C at 8 A (you state 0.58 V). For identical conditions the V30100S is about 0.52 V.

Ok that's not that much.

The really nice thing is the price! Your IR 16CTQ100 costs at Digikey 1.93 Euro in the uninsulated TO-220 package, the VF30100S goes for 1.17 Euro in the insulated TO-220 package.

It's not exactly half the price, but good value for the money for sure. There are even standard Silcon-bridges that cost more than 4 of these.

Have fun, Hannes
  Reply With Quote
Old 25th July 2008, 11:23 AM   #13
MRupp is offline MRupp  Germany
diyAudio Member
 
MRupp's Avatar
 
Join Date: Dec 2003
Location: Frankfurt area
Quote:
(you state 0.58 V)
Quote:
Read the first post carefully and try again
OK, omitted the comma after 25 C - thanks for spotting

On prices, Ebay is your frind; I found all my diodes (IXYS FREDs, IR Shottky's) at Ebay well below EUR 1 per piece, often still in the original tubes, and even the same types that boutique component suppliers (Thel in Germany) sell for an arm and a leg. Lastly, I suggest to use PSUDII to model your power supply to get the max current peaks, and if low forward voltage drop is your primary goal, run them hot (but not too hot).
__________________
Martin Rupp
  Reply With Quote
Old 25th July 2008, 11:55 AM   #14
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
Schottkys are the best when you are after low drop.
No question about this

The only hookup with schottkys is that they often come for a bit lower voltages.
But if your power supplies are not too high voltage, then it is a good option to get lowest power losses.
I do not know the current developement in power Schottky.
But I wouldn't be surprised if there are now higher voltage devices, too.

Now there is, of course, an easy way to compensate: One extra winding in your transformer secondary .....


Best Regards to Dannemark, Dannebrogen och Hannes
You are quite alright by me, man!
The old school very, very Gentle Man of Svea Rike = Sve-rige = Sweden
Lineup
__________________
lineup
  Reply With Quote
Old 25th July 2008, 05:59 PM   #15
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Quote:
run them hot (but not too hot).
Hey, run them hot to reduce power dissipation

Quote:
OK, omitted the comma after 25 C - thanks for spotting
It's a pleasure - especially because that was not intended! I simply edited too much - and forgot that line accidentially

@liney: thanks!! I'm not danske, but nevermind. And of course all the best to you, Hannes
  Reply With Quote
Old 25th July 2008, 09:12 PM   #16
MRupp is offline MRupp  Germany
diyAudio Member
 
MRupp's Avatar
 
Join Date: Dec 2003
Location: Frankfurt area
Quote:
Hey, run them hot to reduce power dissipation
Exactly, if you want get low voltage drop, that is, and btw. I don't think you will save anything worthwhile mentioning, at least not in a normal amp: a lower rated/smaller device and just enough cooling, if any - you need to calculate the correct current values and dissipation, off course.
__________________
Martin Rupp
  Reply With Quote
Old 26th July 2008, 10:08 AM   #17
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Martin, don't worry, I perfectly understood! It's obvious from the datasheet. I was just joking

Have fun, Hannes
  Reply With Quote
Old 26th July 2008, 11:54 AM   #18
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
How about this 'ideal diode' ?

Jan Didden
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W. S. Maugham
Check out Linear Audio!
  Reply With Quote
Old 26th July 2008, 12:32 PM   #19
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Hi Jan, thanks for the article!

Amazing what things exist! Might be interesting for low-power gear! Just a pity that most discrete line-level gear exceeds its 26.5 V voltage rating.

Do not fear smd, Hannes
  Reply With Quote
Old 26th July 2008, 12:41 PM   #20
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by h_a
Hi Jan, thanks for the article!

Amazing what things exist! Might be interesting for low-power gear! Just a pity that most discrete line-level gear exceeds its 26.5 V voltage rating.

Do not fear smd, Hannes
Presumably you can use them floating at any voltage by lifting the gnd lead with a zener or something like that.
Imagine, a 5A diode with 25mV loss only!

Jan Didden
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W. S. Maugham
Check out Linear Audio!
  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
MBR4060PT dual schottky rectifier as bridge rect. jscherer Parts 4 25th February 2009 05:21 AM
LED forward voltage plot ashok Solid State 7 26th October 2007 02:49 AM
Schottky rectifier cricuits dqswim Pass Labs 4 9th January 2004 10:00 PM
Schottky bridge rectifier TheTrax Tubes / Valves 5 3rd January 2004 11:28 PM
International Rectifier Schottky diodes KevinLee Swap Meet 17 30th June 2003 10:37 PM


New To Site? Need Help?

All times are GMT. The time now is 05:24 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