So I need ~1MHz @ ~10amps into <1ohm

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What's the voltage rating on the capacitor?

10A though a 1nF will give over 2.2kV!

Why are you doing this?

There are far more effective ways to generate high voltages than this.
 
Tap your inductor at a reasonable drive point so you can deliver some power.

Use a resonant drive for the MOSFET gates because of the high capacitance of MOSFET gates (up to 3 nF). You're probably better off with a BJT anyway.
 

I think RF power devices are usually bipolar rather than FET?, it's easier to make a bipolar switch fast than an FET due to it's high gate capacitance.


It's more common to use CMOS logic gates as RC oscillators for higher frequencies, 555's don't really go very high.
 

Use a transformer to get to your HV.. all this resonant schtuff will give you more headaches than you care for. How are you going to keep things resonant? You dont even know the ESR of your capacitor. The conditions for resonance will likely be a moving target.
 
A TV flyback is more better at producing high voltages.

What do you want the high voltage for?

Is it for igniting something or just playing around?
 
A bjt is favored for RF because of the high gate capacitance of the big MOSFETs. To switch a MOSFET fast enough to be efficient at 1 MHz you may need 10A of gate current. If you're looking for 10A output, you've gained nothing.

The high gate current isn't a problem at a few KHz, because you don't need it very often.
 
Does this need to be really high powered?

You could build quasi-resonant converter.

The idea is you switch the MOSFET when there's no current flowing so it doesn't dissipate any energy. There are lots of papers that can help you design one whcih can be found from Google.

If you're interested I'll PM you some information you I can't post but I'll have to wait until Tuesday as it's on my work's comptuter.
 
So you need a high energy 200ns pulse.

Have you considered something simple like an automitive ignition coil and capacitor? They give pretty high energy short duration energy pulsed.

You could also charge up a capacitor using a high voltage power supple then discharge is using a spark gap switch.
 
speakerguy79 said:
Anyway, problem now is that my FET driver isn't working. Still trying to debug that.
Click to expand...

As suggested previously, a FET is probably harder than a bipolar - you will need considerable charge and discharge capability to switch it fast enough.
 
I still don't understand what you're doing.

I thougt you wanted a short brief high voltage pulse not a continious wave.

For a continious high voltage you're much better off using a high frequency neon sign transformer or TV flyback rather than messing around with 555 timers and capacitors.

For a short high voltage pulse it's best to charge a capacitor to an imtermediate voltage (about 300V) then discharge it though a transformer. A higher primary voltage on the primary will help to give a faster di/di and thus a faster rise and fall time on the secondary.
 
Lol did you actually carry out my suggestion (see quote below) or did you think of it for yourself?

Me said:
You could also charge up a capacitor using a high voltage power supply then discharge is using a spark gap switch.
Click to expand...
 
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