Re: PLL-controlled SSTC?

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

Original poster: "rob by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rob-at-pythonemproject-dot-com>

Tesla list wrote:
> 
> Original poster: "Jolyon Vater Cox by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
> 
> Has anyone experience of the use of Phase-Locked-Loops to keep a Tesla
coil in
> tune? This approach would appear to have advantanges in combining the
> efficiency of Class D switching with the frequency-tracking capability of a
> self-resonant inverter -are there any serious problems with this approach?
> Also, is dead-time control actually essential for switching
transistors/MOSFETs
> in Tesla coil service?

I've thought about trying this, but that as far as I went.  As far as
dead time, it all depends on how hard you are driving the FET gates, and
how much damping resistance you have across the gate-source junction. 
With a slow ramp up and heavy damping you should be turning the FETs on
much slower than you are turning them off, which means less likelihood
that there will be cross-conduction.  I've never used any resistor
greater than 50ohms across the gate-source.

And if you are really running high power, you want to disable the
internal source-drain diode with an external schottkey diode.

Rob

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