Since I put up this thread I have since upgraded the coil, fet and diode but Im still having the problem. With 9v/3a power supply the output drops from 300 volts no load to 70 volts at around 45ma.
I was wondering if anyone might comment of this: https://docs.google.com/spreadsheets/d/1KDNKAQ2sZJch5CYoSZMCEc1vGZVVrP8h2sKTUL66Opw/edit?usp=sharing If they see anything that might be causing the the problem. Thanks! Bob On Wednesday, January 14, 2015 at 5:05:55 PM UTC-5, gregebert wrote: > > For a MOSFET, there is no static drive-current except for a few nanoamps > of leakage, which can usually be ignored. > The gate-drive-current is whatever is needed to slew the gate-source > capacitance (aka input capacitance). > Using i=Cdv/dt, you can calculate how much drive-current your gate-driver > needs to provide. From the datasheet, you need at least 4.5V for the > gate-voltage. > If you want a turn-on time around 250nsec, you would need about 25mA. > Remember this is not continuous current; it's just there when turning the > MOSFET on or off. > > Take note of the gate-charge graph (Fig 6 on the datasheet) if you are > using more than 5V for the gate; it's a non-linear capacitance which is > typical for MOS devices. > > If you really want to do an accurate assessment, a SPICE simulation is > best though that might be overkill in this application. > > You can get-by with a smaller gate-driver, but that will increase your > switching loss; it's a tradeoff. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/a4fb0563-21f0-4459-8a87-8cbaa7e881a2%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
