Series IGBTs or transistors for high voltage swithing

kubeek

Joined Sep 20, 2005
5,754
I doubt that it would be possible. You would have serious trouble to make them switch all at once, and if they don´t all do that there will be a few that stay off while others are on, and those will release the magic smoke along with great optical and acoustical show.
 

ian field

Joined Oct 27, 2012
6,539
Can I use IGBTs in series for switching about 10 kilo volts load. the original switching element is an expensive vacuum tube.
can i but say 20 IGBTs -(http://pdf.dzsc.com/20090603/200903070140342627.pdf)- in series and fire them isolated so as to switch that high voltage load??
I'd be thinking more along the lines of a TV horizontal sweep tube - but they get a blue glow around the edges much above 8kV.
 

tcmtech

Joined Nov 4, 2013
2,867
It can be done and not with so many stages given there are some IGBT's capable of 2000 - 2500 volt working capacities. 5 - 8 stages of those all being driven with a HV isolation rated multi output pulse transformer could do the job.

The bigger issue is how much current do you need to switch, what frequency and most of all why?
 

DickCappels

Joined Aug 21, 2008
7,540
http://icecube.wisc.edu/~kitamura/NK/Flasher_Board/Useful/research/RSI03066.pd
High voltage fast ramp pulse generation using avalanche transistor
http://icecube.wisc.edu/~kitamura/NK/Flasher_Board/Useful/research/RSI03066.pd
1 nanosecond switching for high voltage circuit using avalanche

High voltage pulse generator circuit


Notes:
Bipolar transistors as avalanche mode switches might be better for your application. They are a lot like thyristors in that once triggered you need to reduce the current in order for them to turn off

2N5551 seems to be a favorite general purpose transistor for avalanche switches. They are characterised by the manufacturers for avalanche operation and are much less expensive that transistors made especially for that purpose.

Edit: First URL corrected.
 
Last edited:

ian field

Joined Oct 27, 2012
6,539
It can be done and not with so many stages given there are some IGBT's capable of 2000 - 2500 volt working capacities. 5 - 8 stages of those all being driven with a HV isolation rated multi output pulse transformer could do the job.

The bigger issue is how much current do you need to switch, what frequency and most of all why?
i'm kinda with the multi secondary pulse transformer idea - might get away with opto couples for slow switching.

I'd put some form of voltage clamp across each stage to catch spikes if any devices don't keep up. Many early solid state CTVs used a balancing inductor with a shared moveable slug for the series horizontal scan transistors - but that was only 2 in series.
High voltage fast ramp pulse generation using avalanche transistor
1 nanosecond switching for high voltage circuit using avalanche

High voltage pulse generator circuit


Notes:
Bipolar transistors as avalanche mode switches might be better for your application. They are a lot like thyristors in that once triggered you need to reduce the current in order for them to turn off

2N5551 seems to be a favorite general purpose transistor for avalanche switches. They are characterised by the manufacturers for avalanche operation and are much less expensive that transistors made especially for that purpose.

Edit: First URL corrected.
The 2n2369 is an old favourite to press gang into avalanche circuits, but not too good on voltage rating. The one you suggest sometimes turned up in video amplifiers and electronic games that give shocks for wrong answers - the voltage rating is nearer the general direction the TS need, but that's the first mention I've seen in the context of avalanche.
 

tcmtech

Joined Nov 4, 2013
2,867
Forget IGBTs - they're too slow for that. MOSFETs are a better choice; the gate capacitance is easier to deal with than purging carriers out of a B/E junction.
100 KHz capable IGBT devices have been around for over a decade now.

https://www.infineon.com/dgdl/Infin...n.pdf?fileId=db3a3043284aacd801288128094553cc 1200 volt 40 amp rated devices have been around since at least 2010

150KHz capable.

https://www.infineon.com/dgdl/wpwarp.pdf?fileId=5546d462533600a401535748c5293ff7
 
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