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Re: 10+MHz SSTC Gate Drive Circuit Finalized



Original poster: dhmccauley-at-spacecatlighting-dot-com 

 > I tried simulating the circuit (in SIMetrix, -at- 100 KHz) & couldn't get
 > much out of it!  I thought to change it a bit & submit my schematic, via
 > hot-streamer, at http://hot-streamer-dot-com/temp/ssdrvr-kch.pdf.
 >
 > A 20 V pp source drives the xfmr, simulating the "monster" circuit.  In
 > the top secondary ckt, D1, C2 & Q1 are as before except C1's capacitance
 > is much reduced (1 uF takes forever to charge; I'd be worried about those
 > 1st few cycles as to MOSFET drive).  The MOSFET/10-ohm branch is replaced
 > by Q2 and both Q1 & Q2 are driven via the D3/R1 pair.  D3 provides max.
 > drive for + excursions while R1 limits xfmr current during "-"
 > excursions.  (Without R1, Q2's b:c junction will short out TX1.)  R3
 > simulates TX1's resistance & R6 is for parasitic suppression (in the real
 > ckt).  R2 damps oscillation a bit.
 >
 > Ken Herrick

20 Vp-p is a bit high.  Thats why the 1uF probably takes for every to
charge.  I use 12V.
I'm also using this same gate drive circuit for a military 1kW Phase Shifted
DC-DC Converter I'm just finishing up at work.  This converter
runs at 1MHz and the gate drive circuit works perfectly.

Dan