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

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diego.fan

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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
 

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.

NPN 15mA to 5 Amperes controlled by 0-5V signal input.png
 

Hi,

I assume this is ASIC development.


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

Klaus
 

Can you use a Typical V to I Converter? That uses an OpAmp?
Provided the loop gain is high, you will get excellent linearity.
V2I Converter NMOS.png

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

N5
 

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