Paul,

Is using a DC charged cap, dumped to a coil the most efficient way to
generate your big multispark?

You _know_ that a high voltage DC power supply has a fair amount of
circuitry in it to make the output smooth and ripple free.  This
circuitry serves no purpose in your system.  And may likely cause you
operating problems.

What could work really well is a 12V DC driven buck-boost converter,
switched by an oscillator that's running at the frequency of your
spark strike rate.  The oscillator would be gated off when you don't
want any spark.  The output of this circuit would directly drive the
coils.

I haven't run the numbers to see if the AC output from a boost
converter could be made fast enough properly drive the coils.  Might
have to play with a SPICE model to see how it would work with real,
available components.



Matt-

Sounds good. Right now I am using an off the shelf,
300 volt, 30 watt power supply that cost $130. I has a lot
of built in safety stuff. For example if it senses a short
it shuts down. It is also regulated to 9 volts which is
required for starting. My current over all design will work down
to 9 volts or lower using two 14 pin dip isolated switching supplies
that put out 15 volts with only 5 volts in. These are used for
driving the FET's. They too have some built in safety features
that prevent low voltage damage to the FET's.

Paul Lamar