Class-E 1kW 13.56MHz RF generator using one MOSFET

For the design and construction details of ion guns, necessary for more advanced designs and lower vacuums.
Linda Haile
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Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Linda Haile » Sat Mar 20, 2010 9:09 pm

http://www.eetasia.com/ARTICLES/2001SEP ... S=DOWNLOAD

I've found this design. Any comments?

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Carl Willis
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Carl Willis » Sat Mar 20, 2010 11:00 pm

Comments about what? Do you have a use in mind? Do you have a question?
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Linda Haile » Sat Mar 20, 2010 11:10 pm

Carl, I recently posted that I was researching driver circuits for RF coils for ion sources. I also suggested transistor driven RF generators as alternatives to RF amplifiers or microwave generators.

I notice this circuit has a series capacitor accross the load, some have a parallel capacitor.

This article seems to be advertising the gate driver. there are probably other ways to drive the transistor. Comments would be welcome.

Then there is the matching circuit.......Is this enough to be going on with?

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Carl Willis
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Carl Willis » Sat Mar 20, 2010 11:24 pm

You know what you plan to do with it, so what are the pertinent advantages you see in this circuit over the alternatives? Why does it interest you specifically? What issues would be relevant to you in a discussion?

Cost?
Robustness?
Ease of construction?
Efficiency?
Safety?
(and so on)?

Throw us a bone! A request for comments is just too general to usefully engage a forum, unless you get lucky and somebody else can either read your mind, or just blathers and happens to scatter tidbits that are relevant to you.

-Carl
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Linda Haile
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Linda Haile » Sat Mar 20, 2010 11:31 pm

Carl, My initial interest in this method is simplicity. It also avoids the hazards associated with microwaves. I was rather hoping that some of those with experience of SPICE might be able to indicate how sucessful this particular design might be, as it only seems to be a simulation.

I believe the basic concept will work but......a killowatt from one MOSFET?.....

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Chris Bradley
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Chris Bradley » Sat Mar 20, 2010 11:41 pm

e-class amps are designed so that resonance is used in sympathy with the natural rates of the gate/drain. ixys make far more powerful mosfets than that even. in eclass mode it helps minimise switching time - it is the switching that causes the heating of the mosfets. i run fairchild 500V mosfets good for 3A, 12A in a pulse. that's 6kW in a pulse, from one mosfet, and there are much bigger ones than that!

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Carl Willis
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Carl Willis » Sat Mar 20, 2010 11:44 pm

Lyn:

>as it only seems to be a simulation.

Huh? The paper you linked (Krausse, from 2001) shows data and photos of a prototype circuit. The Krausse paper is the one you want to discuss?

>a killowatt from one MOSFET?

Therein lies a large number of problems. Look at Table 2. Think about your application. Does anything concern you?

-Carl
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Linda Haile » Sat Mar 20, 2010 11:49 pm

Carl, it does show a prototype circuit, but, at first glance, it looks incomplete.

I will look at table two, thanks for the input.

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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Carl Willis » Sat Mar 20, 2010 11:50 pm

>at first glance, it looks incomplete.

Take a second glance.

I don't know what you think might be missing.
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Re: Class-E 1kW 13.56MHz RF generator using one MOSFET

Post by Linda Haile » Sat Mar 20, 2010 11:55 pm

I see no RF coil or ion source, Carl.

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