On 13.08.14 20:03, Gene Heskett wrote: > Now, if I could just find a 3x higher voltage version of the IRFP250N > hexfet with about the same gate driving capacitance load. The 200v I > managed to punch thru a couple days back. Thats a 35 amp device, and > there is a 78 amp 650 volter available but I wasn't able to compare gate > input capacitance. But I'd bet that 78 amp puppy is 10x the 30 amp > version. > > Sadly, my 8+feet of semi manuals is now pushing 15 to 20 years out of > date.
Gene, what's the part number of the 650 volter? I've recycled a wheelbarrowload of dead-tree semiconductor data manuals, and now only use a suitably organised directory tree of PDFs, all snarfed after a quick google for e.g. "IRFP250 datasheet". (All suitably backed up too, naturally, to defeat the Murphy-Heisenburg surprise: Data which exists only in one place exists only in your imagination - if not now, just wait.) Many of 'em I've never printed out, since a quick glance on-screen is enough for checking pin-out or a parameter. <2c> Incidentally, I've moved from comparing gate capacitance to using Qg, the "total gate charge" figure, since that's what's needed for turn-on¹, and dividing it by the desired turn-on time directly gives the required gate drive current. On almost any MOSFET datasheet, looking at the graph for "Typical Gate Charge Vs. Gate-to-Source Voltage" shows the ramp-plateau-ramp switch-on characteristic which makes a mockery of a single gate capacitance number, I figure. That graph often also tells you how much harder to drive it if you up the Vds significantly. (OK, not much, but it's good to know.) </2c> Erik ¹ For comparable Vgs(on), which has to be the case if we're substituting without changing the gate driver. -- Forecast record-breaking global wheat production for 2014-15: 716.1 megatonnes, up from 714.1 in 2013-14, i.e. up by 2 million tonnes. But global wheat consumption is set to rise by 6.9 million tonnes. - Weekly Times 20.08.2014 (Doesn't look like the extra 80 million mouths/yr are making food less fashionable.) ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
