Hello Christian,
Am 10.09.2012 10:05, schrieb C. Groeger:
Hi Stefan!
I don't know the problem yet. Maybe these small fets went to hot.
My pa design is very simple, 2 x irf 540 parallel in class D, transformer to 50
ohm, Pi filter and variometer.
Operating voltage was 12 V only but nevertheless resulting an Input of 120
watts.
The advantage of a homemade PA is that you normally use cheap and easy
available parts which are easily replaceable. The IRF540 costs about 0.6
Euro so that's all not so dramatic at least.
OK, 120W input power at 12V DC in class D mode. But what was the output
power? Class D, so it is hard switching with a rectangular gate voltage,
cfm? What is the driver you're using to drive the FETs?
If the driver is strong enough to provide good switching times even at
high input Cs then maybe a IRFZ48N or better an IRFP064N may be a better
choice at 12 V DC. They are all cheap and available at Reichelt, you know...
Here, i'm using this PA design:
https://dl.dropbox.com/u/19882028/MF/100W%20475kHz%20PA.png and
https://dl.dropbox.com/u/19882028/MF/DK7FC%20472%20kHz%20PA%2015W%2B100W.JPG
73, Stefan/DK7FC
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