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High volts for high amp efficiency ? - RF Cafe Forums
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Sylvanius
Post subject: High volts for high amp efficiency ?
Unread post Posted: Thu Feb 03, 2005 8:06 am
From say 100 MHz
to 1GHz I would imagine that operating RF amplifiers with a higher supply
voltage should result in higher efficiency. My reasoning is pretty simple.......
Higher Volts must mean lower currents for a fixed output power, where
I assume that the majority of loss is due to I squared R. Anyone care
to comment?
Of course, unless you happen to get just the right
impedance with the chosen rail and output power you will need to impedance
match. It may be the case that a lower supply rail would mean you could
do away with the match and reduce losses incurred in this part of the
circuit.
We then get into greater detail with just where the
transistor is operating (with regard to saturation). Not to mention
those funny games you can play with harmonic terminations and switching
classes such as class E but to keep the discussion simple lets ignore
these for now.
In any case, even if high volts does gain you
somthing the chances of building anything seem slim to me as I find
that most of the new transistor stuff around is aimed at low supply
rails.
Any takers?
Posted
11/12/2012
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