How to let current source has linear V-I and can supply enough current?

1. How to let current source has linear V-I and can supply enough current?

Hi, all

I have a question need your help. Thanks in advance. I want to design a current source(CS) with the below requirement in 180nM.
1. Voltage control and current have the linear relationship.
2. Current mirror can supply enough current. It means if I let MOS W/L low enough to let CS work in triode region, it can has linear V-I. But it's very difficult to supply enough current. So that I have to use many CS in parallel (maybe 10 in parallel)which occupies a lot of area. I don't like to use this way.
3. Add a resistor in source node: source degenerator. I think it can make V-I more linear, but current will be lower, right?

May I ask if there is other circuit structures or methods which can realize linear V-I and enough current at the same time?

Regards

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2. Re: How to let current source has linear V-I and can supply enough current?

A simple transistor is a method that gives linear response. However it is resistive drop therefore it generates heat. You may decide that several devices in parallel is the easiest solution, and/or several pins acting as multiple heat sinks in contact with the pcb.

Simulation showing that the load receives a proportional Ampere level, based on the volt level coming from the left.

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3. Re: How to let current source has linear V-I and can supply enough current?

Hi,

I assume this is ASIC development.

In either case specifications like:
* voltage(s)
* current range
* linearity
are essential.

Klaus

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4. Re: How to let current source has linear V-I and can supply enough current?

Can you use a Typical V to I Converter? That uses an OpAmp?
Provided the loop gain is high, you will get excellent linearity.

You can use PMOS as well. And even have it Supply Referred.

N5

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