An RF Class E Amplifier
I have a problem about class E amplifier design . that is :
It's RFC in DC current! my mosfet going hot and i think its for low dc impedance of RFC( i think it is low)
So is it right?
so , its inductance is very big (at one mega hertz) (my mean is XL).
What should i do ? is here any suggestion?
Thank you for your attention.
Goldsmith
In a class E amplifier you need a capacitor across the transistor that resonates with your RFC or rather your DC feed inductor. have you done this?
Frank
Dear Frank. thanks for your attention. yeah. i have a capacitor in parallel with DS . and matching and reform network. bu my mosfet going hot. i confused. what is problem? my RFC is just several turn that makes 1K ohms at mega hertz. but its dc impedance is 0.1 ohm. is it possible guide me, please?
Regards
Goldsmith
The DC resistance of the choke would be the least issue making the transistor getting hot. Actually in Class-E the value of the choke inductance is higher than chokes in other power classes.
In Class-E to make the transistor working as a perfect switch (which means best efficiency and lower temperature of the transistor) the Q of the series C and of the series L at the output, should be high enough to allow passing through only the fundamental and removing the harmonics.
The transistor works as a perfect switch, when it is ON the collector/drain voltage is zero, and when it is OFF the collector/drain current is zero.
Thanks very much vfone