i need help for "square rooter"

[volkan]

my term project is about "square rooter" integrated circuit. I have to explain its working principle and simulate it on H-spice
First of all i need to understdand the circuit, do you have any links about this(how it works and in what way it is used practically), I will be happy if anyone help me to understand this circuit or post the project he/she made about square rooter
I am uploading the scheme of it

 

[fuzzy]

Dear Volkan
Check LM194 super pair ic.
www.national.com.
And you read about log amplifer.

Kolay gelsin

 

[zorro]

Hi volkan,

A "square rooter" can be obtained placing a squarer in the feedback part of an operational amplfier. That squarer is a block with a relationship between output current and input voltage of the form Io=k*Vi^2. It is made with a multplier cell.
Regards

Z

 

[cedance]

hi,

how abt taking a log of the number and then its antilog? i have studied the implementation (not board level) of thse circuits using Opamp in my course.. any badsic book has them too... hope this helps.. incase u are interested i ll try to get those materials posted here.. good luck..

/Am

 

[volkan]

Well, i tried to send the scheme of the circuit but i think i have no permission to attach it yet.
I am not makin square rooting with opamp , this is an analog integrated current mode circuit and there are 19 MOSFETs in it. It has 2 input currents and output curent is (I1*I2)^0.5 .

 

[bastos4321]

Well, i tried to send the scheme of the circuit but i think i have no permission to attach it yet.
I am not makin square rooting with opamp , this is an analog integrated current mode circuit and there are 19 MOSFETs in it. It has 2 input currents and output curent is (I1*I2)^0.5 .

Do not forget that those king of circuits are based on the square law of a MOS, therefor you should use big "L" to have a square law, also the characteristic varies with process and temperature.

Bastos

 

[volkan]

And i forgot to give this the ref. of application of this circuit, if you have ieee acess,it is shown here :”A Current Mode Circuit For Euclidian Distance Calculation” Chuen-Yau Chen, Chun-Yueh Huang, Ju-Ying Tsao, Bin-Da Liu.
They used the square rooting circuit in here (euclidian distance calculation) but
it doesnt include the working principle of square rooter., i tried to solve equations but i it is a bit hard for me now( i am new in analog integrated circuits).
Thanks for your helps...
Regards

 

[nand_gates]

Hi Volkan,
You can refer to following book. This one contains square rooter circuit
with theory of working... and its applications.
One application of sqare rooter circuit is in a circuit wich calculaters RMS values
for sinusiodal current and voltage waves.

Design With Operational Amplifiers and Analog Integrated Circuits.
Author: Sergio Franco

 

[volkan]

Hi,
Can you upload that book here ?
Best wishes...