Re: SSTC bridge driver SNUBBER circuits

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: dhmccauley-at-spacecatlighting-dot-com 

Not true.  You can have ringing, and still have a perfectly clear
understanding of what is occurring at the gates.  There is no need to make a
circuit more complicated if
the added circuitry is only for "aesthetic reasons" and making the gate
drive "look" clean.  I recently finished a design for a DC-DC converter
operating at 2MHz for the
F-22 Raptor program.  If you looked at the gates of this particular design,
there is  ringing.  However, because this ringing occurs in a region that
doesn't affect
performance in any way, its perfectly acceptable.  The ringing was
completely predictable (in both simulation and lab testing), and therefore
tightly controlled.

Dan


 > On the surface that is true, but it is an indication that you don't have
 > tight control over what the gates are doing and that is undesirable.
 >
 > George


 >  > With all this talk about ringing on the gate . . . The first thing you
 > need
 >  > to understand is, that if the ringing occurs well above the turn-on
 > point of
 >  > the gate and is under
 >  > the maximum voltage rating of the gate, there is nothing else you need
 > to
 >  > do.  Its only when the ringing has a large enough amplitude that it
 > swings
 >  > into a region that
 >  > either bring the MOSFET out of saturation, or exceed the maximum
 > ratings of
 >  > the gate, that a snubber circuit is necessary.
 >  >
 >  > Dan