I'm working on 'improving' the Kettering system on my 1948 tractor. (Max 2000 engine RPM and 3 amps to the coil) Initially I was going to use an ignition IGBT, such as the ISL9V5045S3ST_F085, which has all of the snubber circuitry already built in.
The problem is that the only practical way to switch the ignition coil, which is mounted on top of the distributor and connected directly to the points by a spring contact, is by switching the high side, and no ignition IGBT's are made that will do that.
As the switching speed and current are both low I decided to use a P channel mosfet, many of which now have very low Rds.
I cannot find any information on how you would design a snubber circuit for a P-channel mosfet on the high side, or even if such a circuit was needed.
Can anyone steer me in the right direction?
The problem is that the only practical way to switch the ignition coil, which is mounted on top of the distributor and connected directly to the points by a spring contact, is by switching the high side, and no ignition IGBT's are made that will do that.
As the switching speed and current are both low I decided to use a P channel mosfet, many of which now have very low Rds.
I cannot find any information on how you would design a snubber circuit for a P-channel mosfet on the high side, or even if such a circuit was needed.
Can anyone steer me in the right direction?