W
Winfield Hill
colin wrote...
Two different effects... The slowing of the turnoff means the
coil can flyback and dI/dt discharge as it's doing so, without
reaching the avalanche voltage, if carefully done.
You're asking if oscillation doesn't happen in the event of a
slowed transition, as in the zener case? It certainly can with
high-voltage MOSFETs, although the dV/dt slewing output helps to
hide it, on the one hand, and perhaps to dampen it, on the other.
Winfield Hill wrote ...
If the RF feedback path is wholy internal how would this affect the
method of using a higher gate drive resistance to slow the current
fall to limit the voltage to less than the breakdown voltage?
Two different effects... The slowing of the turnoff means the
coil can flyback and dI/dt discharge as it's doing so, without
reaching the avalanche voltage, if carefully done.
or does the zener just add more parasitics to make the difference?
You're asking if oscillation doesn't happen in the event of a
slowed transition, as in the zener case? It certainly can with
high-voltage MOSFETs, although the dV/dt slewing output helps to
hide it, on the one hand, and perhaps to dampen it, on the other.