Hi Nigel,
            Can you give some more info, like do you have to switch "on"
and"off". Often some  scr's in series do this type of thing well if you need
to "fire" a cap into something. Do you need to switch rapidly on and off?
Bipolars will swich off Ok if you use a snubber but will suffer from 2nd
breakdown if swithed on. What current are you switching? high current, high
voltage  IGBT's are available at a -price.

George

----- Original Message -----
From: "Nigel Orr" <nigel@AXONINSTRUMENTS.CO.UK>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, July 31, 2003 1:17 PM
Subject: [EE]: Sharing FET voltage


> I have an application where I need to switch voltages higher than a single
> FET can cope with.  Does anyone have any experience with connecting serial
> FETs for higher voltage tolerance?
>
> I've figure out that each FET needs to have it's gate driven separately to
> maintain Vgs voltage relative to its source, but I can't see a good way to
> do that without affecting the voltage each FET sees when switched off.
>
> To complicate matters further, part of the circuit needs to switch this
> voltage quickly, preferably transition from off to on in less than 10us.
> And it's got to work at temperature, so discretes are preferable if
> possible.
>
> Alternatively, does anyone know of FETs with 2kV switching capability
> (current under 500mA), or have any other wacky suggestions?
>
> Any ideas welcome,
>
> Nigel
>
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