Techniques to improve power gain
时间：04-04
整理：3721RD
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Hi,
I designed a power amplifier, it has some power gain (Ap) and bandwidth(BW) after perfectly matching at input and output.
I want to know
1. How to increase the Ap without changing BW?
-I know the below case but I would like to know if there any other ways
a) By increasing transistor widths, I can increase gain -- but in this case I need to change matching again, isn't it? and I am not sure it's impact on bandwidth.
2. How to increase the Ap even when BW increases or decreases?
I only know this way
-By connecting many stages in cascade, power gain increases but that decreases bandwidth.
And do we all the time need to change input and output matching networks if we change anything in the rest of the circuit?
I designed a power amplifier, it has some power gain (Ap) and bandwidth(BW) after perfectly matching at input and output.
I want to know
1. How to increase the Ap without changing BW?
-I know the below case but I would like to know if there any other ways
a) By increasing transistor widths, I can increase gain -- but in this case I need to change matching again, isn't it? and I am not sure it's impact on bandwidth.
2. How to increase the Ap even when BW increases or decreases?
I only know this way
-By connecting many stages in cascade, power gain increases but that decreases bandwidth.
And do we all the time need to change input and output matching networks if we change anything in the rest of the circuit?
Increase operation current.
Too wide width results in limiting bandwidth.
Can you understand the followings ?
https://www.edaboard.com/showthread.php?384620#18
https://www.edaboard.com/showthread.php?384784
That means increasing gate to source voltage (Vgs), this is fine for CLASS A operation. But what if I want my amplifier to operate in CLASS AB Biasing.
Invoke cascode configuration.
And keep Vds large, that is, large Vdd.
However you have to consider break down voltage of devices.