IGBT amplifiers - 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 6th March 2007, 04:21 AM   #1
diyAudio Member
 
Join Date: Oct 2006
Default IGBT amplifiers

I've been reading a little about IGBT's. from What I read, they seem like a cross between a bipolar transistor and a mosfet. I know very little about these devices. Anybody built an amp with them? Either class D or class AB.
  Reply With Quote
Old 6th March 2007, 06:22 AM   #2
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
Most IGBTs have poor safe area for a linear (class AB) amplifier, and are too slow for anything but a subwoofer amp in class D.
__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 6th March 2007, 07:15 AM   #3
MOER is offline MOER  United States
diyAudio Member
 
Join Date: Aug 2003
Location: SIMI VALLEY CA
Default IGBTs

IGBTs are not slow. We are using them at a switching frequency of 100 and 150KHz and the newer generation of IGBTs from IXYS can switch even faster.

Stephen
Zed Audio Corp
  Reply With Quote
Old 6th March 2007, 07:34 AM   #4
diyAudio Member
 
Join Date: Feb 2007
Location: Naples, Florida
Send a message via MSN to stahlight
Default IGBT characteristics

The IGBT or Insulated Gate Bipolar Transistor is indeed a hybrid MOSFET/BJT device. MOSFET's traditionally have low transconductance (gain). The old name for an IGBT is a GEMFET or Gain Enhanced MOSFET. As its name implies they have higher gain, but are a voltage controlled device (BJT are current controlled).

They function similarly to MOSFET's but with one limitation: secondary breakdown, just like a BJT, and like a BJT they also dont share loads without balancing resistors (i.e. operating in parallel). Think of them as a MOSFET input with a BJT output.

Amplifier considerations: I have never seen a P-channel IGBT, just N-Channel, so you will need to design a dual N-Channel output.

Hope this burned away some of the fog.

~G6~
__________________
--
"Success is not a destination; it's a journey."
  Reply With Quote
Old 6th March 2007, 09:10 AM   #5
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Some facts about IGBTs:

- Fast IGBTs intended for high frequency switching are actually much faster than standard audio output bipolar transistors. There is a tradeoff between turn-off speed and Vce-sat. Slower devices tend to saturate at Vce=1.0-1.5V while the faster devices saturate at Vce=2.0-3.0V. IGBT model selection is very important.

- There are some IGBT models with positive temperature coefficient intended for direct paralleling, while most models have negative temperature coefficient and can't be paralleled without emitter resistors or some other current sharing aid. See SKP10N60 from Infineon for example.

- There are P-channel IGBTs too. The GT20D201/GT20D101 complemantary N/P audio IGBT pair was once available from Toshiba, and a circuit using them was published in Elektor some years ago. Check the following link: http://www.arky.ru/audio/shem/igbt/igbt.htm

- All modern switching IGBTs feature square SOA, like MOSFETs.

- IGBTs are easier to drive than MOSFETs because the capacitances and gate charges involved are almost 5 times lower.

- The main advantage of IGBT over MOSFET in high voltage switching applications is much lower conduction losses given the same package or die size. Switching losses are higher, though. Check SGH80N60UF for example, Vce-sat for 40A is only 2.1V in the 25ºC to 125ºC temperature range. Any similar MOSFET would exhibit a two or three-fold increase in Rds-on at 125ºC with respect to 25ºC.
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 7th March 2007, 04:53 AM   #6
djk is offline djk
diyAudio Member
 
djk's Avatar
 
Join Date: Feb 2001
Location: USA
"IGBTs are not slow. We are using them at a switching frequency of 100 and 150KHz and the newer generation of IGBTs from IXYS can switch even faster."

Slow for a full range amp, OK (as I said) for a sub amp.

"All modern switching IGBTs feature square SOA, like MOSFETs."

Most data sheets do not show forward bias SOA at DC (needed for linear use) because they are intended for switching (they show turn-off SOA instead).

"a rugged device with a square switching SOA" (quote from IR sheet)

For a class D amp with a B+ below 200V I would choose a Hexfet.

As Nelson Pass once observed, we can build an IGBT amp (and he did with the afore-mentioned Toshiba parts), but should we?

__________________
Candidates for the Darwin Award should not read this author.
  Reply With Quote
Old 7th March 2007, 08:00 AM   #7
diyAudio Member
 
Join Date: Aug 2003
Location: Prague,Czech Republic
Don't use in construction devices, which exist only in two types ( complementary ), made only by one firm. You have not guarantee, that tomorow they will be out of production...
  Reply With Quote
Old 7th March 2007, 06:40 PM   #8
Piersma is offline Piersma  Netherlands
diyAudio Member
 
Piersma's Avatar
 
Join Date: Jan 2003
Location: Netherlands
Default Elektor IGBT amp

Hi,

This IGBT amplfier was published some years ago by Elektor.
The specs of this amplifier were quite good according to measurements done by Elektor.

best regards,
Piersma
Attached Images
File Type: jpg igbt amp2.jpg (57.5 KB, 2716 views)
  Reply With Quote
Old 7th March 2007, 07:01 PM   #9
diyAudio Member
 
jacco vermeulen's Avatar
 
Join Date: Oct 2004
Location: At the sea front, Rotterdam or Curaçao
Send a message via Yahoo to jacco vermeulen
Elektor did 2 IGBT amps.
The first was an IGBT upgrade in 1995 of the Giesberts designed HEXFET amplifier.
The second IGBT design came in 1997.
An early 1995 Elektor issue had an page on IGBTs, Februari or March number.
__________________
The buck stops Here
  Reply With Quote
Old 8th March 2007, 01:26 PM   #10
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
See the attached SGH80N60UF SOA figures, which demonstrate that SOA is only restricted by dissipation and not by secondary breakdown as stated. IGBTs are secondary-breadown free.
Attached Images
File Type: gif sgh80soa.gif (20.8 KB, 2092 views)
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  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
Has somebody used IGBT in power amp boske Solid State 32 30th November 2013 01:23 AM
IGBT Still Alive Stee Solid State 7 2nd October 2008 10:48 PM
H-bridge IGBT speakerguy79 Solid State 0 21st October 2006 12:42 AM
IGBT's for sale... jazzpeter65 Parts 0 9th February 2004 07:57 PM


New To Site? Need Help?

All times are GMT. The time now is 04:01 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