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Re: SSSSTC Coil questions for Mr. Steve
Original poster: "Steven Ward" <srward16-at-hotmail-dot-com>
Hi Dave, i will try to answer your questions:
>I suspect the delays are from your cascaded GDT's.
Cascaded? I think you may have misunderstood my driving scheme. In the
schematic i have a TC442X pair driving a small GDT. This drives 1
half-bridge (which makes up one beefy gate driver). This half-bridge ALONE
drives ALL 16 mosfets. There is one large GDT per each 4 fets. So 4 gate
drivers, all of their primaries connect to that half-bridge. There is no
cascading of GDTs.
Maybe a high
>current loop with indiividual I>V converter transformers at each switch
>pair may reduce delays and losses.
If i knew more about electronics i would be able to follow you... to tell
you the truth, im a freshmen in college and havent take a single course in
electronics yet. I *THINK* i understand what your saying, but im not sure
how to design/implement this.
I would also look at possibly
>stages in next attempt, as example, IDK if you really need the 74LS14
>inverters, you may have enough drive from LT016 to direct drive the
This is correct, im going to pull the 74hc14 out of there, its adding like
60ns total that is not needed. I used it to ensure noise protection, but
its really not needed. Its all built on a breadboard right now so this is
an easy change.
>I need a litle more detail with your GDT configuration, (core, number of
>I assume you are using one per FET totem pole, with 4 primaries paralleled
>to master driver?
The cores are (if i can remember!) F-114A-77. They are type 77 material
with a U of 2000. I think im using 11 turns on the transformers. I have 5
windings on each core, 4 of the windings are driving 4 fets (or 2 of the
half-bridges) and 1 primary going to the half-bridge gate driver mentioned
>Perform a little calculus and determine where the 2nd derivative (most rapid)
>slope change is. I agree with you, you are probably at diminishing
>4-5 stages (8-10X Vin multiplication). Another idea struck me with this
>design, you might be able to turn this topology into a full bridge and double
>applied voltage again. Need to think about it a little more... :^?
Umm, start calculus this semester soo...
anyway, this IS a full bridge! If you look at my page im using two 4 level
inverters and are running oppositely of eachother. Its effectively a full
bridge to the best of my knowledge. I basically did this because normally,
the output of a single inverter would go through a DC blocking cap- through
a load- then back to ground/neutral. I didnt like the idea of that, so i
built another inverter to go on the other side of the load.
>Another possibility is build a "voltage adder" circuit using multiples of this
>circuit to drive a driver transformer cascade. Imagine what could be done
>with 30-60kV pk going into base of resonator like a magnifier!
Im not sure what a voltage adder is, example?
30-60kv base drive sure would allow for some massive powers to be pushed
into the resonator, but this sounds like a daunting feat.
Dave, I hope we are starting to get clear with eachother on this topic. My
limited knowledge doesnt help things, but im trying ;-)