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Terry's DRSSTC - Controller - Happy Day!! :-))

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi All,

Oh happy day today!!

The long thought out messy DRSSTC controller circuit seems to be working perfectly in today's "first" bench test!!!


This circuit takes all the RUN, PULSE IN, FAULT, etc. signals and turns them into digital pulses that go to the gate drive card. I made it on a proto-board for now since it would have been an expensive 4-layer board otherwise and I wanted it to be versatile.


I wired it all up in bed last night. Shockingly, I did not may any wiring errors even with the help of a little Canadinan Mist to steady my nerves :o))

So I hooked it up to a few toys:


The first look was at the dead time circuit using the 1N4148 diodes, 1K resistors, and 1000pF caps. These are the gate drive output signals with a 100kHz `8 amp input to the CT:


Yeah!! 1uS dead time and it could be a LOT longer!! But great for the max deadtime in my case. If I simply remove the caps I get:



164nS! smaller than is practical... So I seem to have the dead times under total control!!!!

Here is the CT input signal vs. the gate drive output:


Can't get much better than that ;-))

So I got out the Pearson 411 and set the scope input on 50 ohms and all that good stuff to look at the total I(Lp) to gate drive delay:


Looks like about 200nS. That actually gets better at higher currents! The "cheap" CT seems to have a little delay and I ordered up some better ones. However, this is certainly in the "good enough" range now!!

So for this weekend, everything on my project's todo list worked perfectly!!! So I will stop for now before I go busting something ;-))