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Date: Thu, 09 Aug 2012 23:49:26 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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In-Reply-To: <CAKvcm2cp1WDFZgufoDRr0D7yxBijentyvvDDkrhQzQ5vwFUeeg@mail.gmail.com>
Subject: Re: LF: Caps for Class-E amp
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Am 09.08.2012 23:33, schrieb Dimitrios Tsifakis:
> Well, that's why I thought the monster IXYS FET I used, which is
> obviously an overkill, will probably be hard to kill. I can't possibly
> exceed the 55 A current limit (it's fused to much less than that)
However the peak current in the class E is much higher than the average 
DC current of the supply/battery. 55A peak current at 12V DC supply 
voltage and 100W RF power is not to unrealistic, if the load impedance 
is a bit sub-optimal ;-)

What type of IXYS FET do you use?

For a 24V 200W class E is would use a IRFP260N. Just for fun, that one 
would be nice too: IRFP4568 
<https://dl.dropbox.com/u/19882028/Datenbl%C3%A4tter/IRFP4568.pdf> Check 
out that data sheet. May be a bit hard to drive the gate at 137 kHz, 
maybe to hard for a ICL7667 but a IXDD614 will have no problem at all.

Sorry, i just like the topic. Of course your concept will work too!


>   and
> I won't exceed the drain (or gate) limits as it's already quite high
> (500  V) but also I will add a beefy transzord or zener to ensure
> compliance. The capacitors are maybe more likely to get damaged, so
> that's something I need to consider by overengineering that part.
>
> In any case, I won't experiment with kites, just good ol' plain earth
> antennas which are quite robust mechanically and won't fall on the
> ground because they are already there :-)
>    
LOL! That is nice!

Wish you good luck.

73, Stefan/DK7FC

>
> 73, Dimitris VK1SV
>    

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Am 09.08.2012 23:33, schrieb Dimitrios Tsifakis:
<blockquote
 cite="mid:CAKvcm2cp1WDFZgufoDRr0D7yxBijentyvvDDkrhQzQ5vwFUeeg@mail.gmail.com"
 type="cite">
  <pre wrap="">
Well, that's why I thought the monster IXYS FET I used, which is
obviously an overkill, will probably be hard to kill. I can't possibly
exceed the 55 A current limit (it's fused to much less than that)</pre>
</blockquote>
However the peak current in the class E is much higher than the average
DC current of the supply/battery. 55A peak current at 12V DC supply
voltage and 100W RF power is not to unrealistic, if the load impedance
is a bit sub-optimal ;-)<br>
<br>
What type of IXYS FET do you use?<br>
<br>
For a 24V 200W class E is would use a IRFP260N. Just for fun, that one
would be nice too: <a
 href="https://dl.dropbox.com/u/19882028/Datenbl%C3%A4tter/IRFP4568.pdf">IRFP4568</a>
Check out that data sheet. May be a bit hard to drive the gate at 137
kHz, maybe to hard for a ICL7667 but a IXDD614 will have no problem at
all.<br>
<br>
Sorry, i just like the topic. Of course your concept will work too! <br>
<br>
&nbsp;<br>
<blockquote
 cite="mid:CAKvcm2cp1WDFZgufoDRr0D7yxBijentyvvDDkrhQzQ5vwFUeeg@mail.gmail.com"
 type="cite">
  <pre wrap=""> and
I won't exceed the drain (or gate) limits as it's already quite high
(500  V) but also I will add a beefy transzord or zener to ensure
compliance. The capacitors are maybe more likely to get damaged, so
that's something I need to consider by overengineering that part.

In any case, I won't experiment with kites, just good ol' plain earth
antennas which are quite robust mechanically and won't fall on the
ground because they are already there :-)
  </pre>
</blockquote>
LOL! That is nice!<br>
<br>
Wish you good luck.<br>
<br>
73, Stefan/DK7FC<br>
<br>
<blockquote
 cite="mid:CAKvcm2cp1WDFZgufoDRr0D7yxBijentyvvDDkrhQzQ5vwFUeeg@mail.gmail.com"
 type="cite">
  <pre wrap="">

73, Dimitris VK1SV
  </pre>
</blockquote>
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