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How to split the transfer function into two parts for filter design?

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glenjoy

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I have this transfer function and the op amps needed to do the said filter design is only 2.

Please do give some inputs.
 

Filter Design help

Are you trying to do this for a compensator for a buck converter?
 

Filter Design help

nope, just for a simple filter design
 

Filter Design help

Hey the easiest way is to split the transfer function into two parts, T(s) = T1(s)*T2(s)

where T1(s) = (s+1000)*(s+1000)/(s+100)
T2(s) = 1/(s+100000) * (s+1000)/(s+100)

The LHS terms in T1 and T2 can be implemented using passive filters. The RHS can be implemented by an active filter using a parallel combination of RC both at the input and on the feedback loop, creating a delay equilizer.

Now you can cascade, LPF with the delay equilizer in the first stage and HPF with delay equilizer in the second stage.

This solution is robust enough for a filter which really does not require tunability and also does not require a very high Q.

I hope this explanation helps because I cannot currently plot a schematic and scan it for you.
 

Filter Design help

What is LHS and RHS, we are not allowed to use inductors.

Cannot really understand what you mean.
 

Filter Design help

Well, the LHS and RHS meant left hand side and right hand side of the transfer functions. What I meant to say was the first term in the equation of T1 which are (s+1000) and 1/(s+100000) can be implemented using passive components. The other common term can be implemented by an active filter.
 

Filter Design help

hi
see filter solutions
may be help you.
regards
 

Filter Design help

I already used filter solutions, it gives me three op-amp design.
 

Re: Filter Design help

Dear Glenjoy,

I am attaching a rough schematic with this post. Please pursue it to get the architectural idea.

I hope that it gives some insight.
 

Filter Design help

I still do not know how to get the R's and C's.
 

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