Balanced IGBT for amplifier output - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 13th December 2008, 01:56 PM   #1
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Default Balanced IGBT for amplifier output

Here is my version of IGBT named B-IGBT, like balanced IGBT, very suitable for the output stage of an amplifier.

Very easy to drive, input MOS-FET drives the same current for both output transistors etc.

Output NPN/PNP's can be paralleled to raise current capability.

Brainstorming: please post suggestions for complete high performance amplifier including this output B-IGBT.

Click the image to open in full size.
  Reply With Quote
Old 16th December 2008, 06:38 PM   #2
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Maybe something like this would be a good starting proposal.



Click the image to open in full size.
  Reply With Quote
Old 16th December 2008, 06:59 PM   #3
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Ingenius circuit! Haven't seen that. Possible drawback: the output cannot swing close to the rail as there is no possibility to feed the mosfet with a higher supply voltage, and there are two Re's in series which also limits output level with high currents. You'll need a higher supply voltage than usual for a specific output.
Other than that, why not try it. You probably can tack it onto a 'normal' Vas driver.

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 16th December 2008, 07:09 PM   #4
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Well Jan, first thanks, than some explanations.

Output rails are +/- 50V and are separate from supply rails of voltage amplifier; these can be arbitrary from +/- 55V up.

Two resistors valued 22ohms flows driver current and therefore are not influential to output current nor limits it.

I have to remind you that MOS-FET's are drivers here.
  Reply With Quote
Old 16th December 2008, 11:18 PM   #5
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
A potential problem I see - the NPN:s and PNP:s might not share current that well under all conditions. This is because they are driven with about the same current but current gains can be all over the place. Maybe beta-droop comes to your rescue though.

Doesn't Bryston use something similar but with BJT drivers?
  Reply With Quote
Old 17th December 2008, 12:02 AM   #6
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
technically it is like parallel 2 output transistors, but using one PNP+ one NPN

what you pay is some extra volt drop
what you gain is: ????
__________________
lineup
  Reply With Quote
Old 17th December 2008, 06:52 AM   #7
diyAudio Member
 
Workhorse's Avatar
 
Join Date: Dec 2004
Replace the mosfet driver with bipolar and you will have Quad complementary output stage of Bryston amps..........nothing new
  Reply With Quote
Old 17th December 2008, 08:10 AM   #8
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
What we are talking about here is new version of Insulated Gate Bipolar Transistor or IGBT semiconductor in balanced configuration (BIGBT).

Implementations of BIGBT device are versatile and can be used in output stages of different kind of power devices.

Current devided among NPN/PNP devices is similar like in parallel configuration, the transistors have to have similar-equal Hfe. MOS-FET driver is symmetricaly loaded with one BE current per output pair.

In audio:
What you gain is voltage driven powerful output device which can be easily managed by VAS stage. That means you need less stages and shorter signal path is guaranteed. Also you gain positive performance of both kind of output configuration: common emitter and common collector follower.
  Reply With Quote
Old 18th December 2008, 12:38 AM   #9
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
BJTs are voltage driven too Drive current doesn't fall with decreasing frequency though like with mosfets.
  Reply With Quote
Old 18th December 2008, 08:50 PM   #10
diyAudio Member
 
Lazy Cat's Avatar
 
Join Date: Sep 2007
Megajocke I know that you're very curious about post#2 so why don't you just try it.

It's my favourite output stage by far and believe me I tried them all.
  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
Balanced compound-IGBT power amp idea revintage Solid State 10 21st January 2008 05:27 PM
IGBT output impedance darkfenriz Parts 10 21st December 2004 12:51 AM
ono balanced output pamaz Pass Labs 6 4th March 2004 12:20 AM
balanced output wuffwaff Solid State 14 16th January 2002 07:54 AM


New To Site? Need Help?

All times are GMT. The time now is 10:16 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