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Low voltage headroom current mirror with high output imp

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ericlps

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low voltage current mirror

Hi.. any one know any technique which can be used to design a current mirror capable of providing 10mA with low voltage headroom (less than 0.3V for the transistor to operate, the signal swing takes about 2.7V with 3V power supply) and high output impedance (more than 5k)? Is it possible cascode current mirror can achieve such a low voltage headroom? i'm doubt with it as cascode current mirror tooks 2VDS to operate. Thx
 

self cascode current mirror low voltage

I think you cannot used cascode. You can easily achieved ro > 5k using longer channel for only single transistor
 

voltage headroom cascode current mirror

You also can added a aux opa to the output stage for added the output resistor.(gain boosting)
 

low voltage mirror

Thx, currently i'm trying out wide swing CM. Looks like it can provide 100k, but i'm looking forward to achieve megaohm range. :roll:
 

self biased cascode current mirror

I'd try out cascode but seems it cant provide the required output impedance (>5k when 300 NMOS parallel together to provide high output current >10mA) ) although high swing cascode or self-bias cascode manage provide to provide higher output impedance (with less parallel mos only) but not feasible for high output current i required. Do u think current mode method may work by adding active feedback? I guess the active feedback can regulate or provide a constant vds voltage at the copying transistor (which will operate in slight triode region) thus provide less variation over the Iout and larger output impedance. Any brilliant idea? 8O Thx
 

I am designing a current mirror for limiting amplifier which has a 1.2v headroom. Can anyone give me an idea how to design?
thank you very much.

current=0.16mA
high output resistance.
 
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