wizardz
Member level 2
I'm think about changing the bias current of an amplifier to achieve different output impedance.
The problems lies in the switching on/off the current source feeding the MOSFET of the amplifier. For example, I can cascode a CMOS switch on the current mirror source and then cut-off/open the current branch.
I find there involves some design considerations, it is hard to define the DC voltage at the node where switch and current source is conected during "on" state. Also, cascoding a MOSFET can consume voltage headroom.
Is there any better ways?
Thanks!
The problems lies in the switching on/off the current source feeding the MOSFET of the amplifier. For example, I can cascode a CMOS switch on the current mirror source and then cut-off/open the current branch.
I find there involves some design considerations, it is hard to define the DC voltage at the node where switch and current source is conected during "on" state. Also, cascoding a MOSFET can consume voltage headroom.
Is there any better ways?
Thanks!