Introduction to Fast Analytical Techniques: Application to Small-Signal Modeling - by Christophe Basso

Thread Starter

kiroma

Joined Apr 30, 2014
236
Hey everyone.
So I found a pdf of the presentation this guy did in 2016 (which I had no idea and wasn't in the same country probably), and I found it difficult to get just by the pdf. So I burned some tokens on Claude Opus 5.5 to make it check the math and complete the presentation.
This is what I got: (attachment)

Description:
Christophe Basso's APEC 2016 seminar on FACTs (Fast Analytical Circuit Techniques): deriving transfer functions of linear circuits by inspection instead of nodal equations and heavy algebra. It starts with a critique of high-entropy expressions, which are correct but impossible to interpret or use in design. The goal is low-entropy forms, with gain, poles and zeros kept separate, where every term has a physical meaning. The foundation is the time constant: with the excitation turned off, the resistance seen by each capacitor or inductor is enough to build the denominator. Zeros are found by inspection or with null double injection (NDI), which looks for the conditions under which the signal fails to reach the output. One example compares the method with a Thévenin analysis, and results are checked in SPICE and Mathcad. The method is then extended to second-order networks, such as the buck's LC output filter (with parasitics), with a notation that tracks the state of each reactance. In the applied part, the PWM switch model linearizes only the switching cell and makes it possible to analyze CCM buck and buck-boost converters: control-to-output and input-to-output transfer functions, input and output impedances, and the right-half-plane zero.

Hope at least someone find it interesting someday, then my effort to post here is paid.
 

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Thread Starter

kiroma

Joined Apr 30, 2014
236
It sounds somewhat like dominant-pole analysis that has been presented in textbooks for decades. Maybe it is an extension of that.
It's not the dominant-pole analysis, it's a method to get the transfer function by inspection and in the form of "low entropy". So this is faster, intuitive, and useful.
 

Thread Starter

kiroma

Joined Apr 30, 2014
236
Forgot to mention: there are few graphical errors, but it doesn't prejudice the understanding. I made it with Opus 5.5 on Ultracode (maximum effort), thus there's not much room for improvement.
 
I went thru the presentation and I am reminded very much of the three semesters of senior level courses in my engineering collecge 1969 thru 1972."Feedback Systems (1),Feedback Systems(2), and Feedback Systems(3)!
We DID learn how to accurately model a "Closed Loop Transfer Function", which in the real world we would evaluate how it ferformed in the particular application, and adjust it as required. Usually we came quite close initially. I DID need to bail out an associate one time who found that the calculated values did not work.
That education did provide useful insights on quite a few occasions but only a very few times did I need to use any of the math. That part of the education was also useful directly a few times.
 
Last edited:

Thread Starter

kiroma

Joined Apr 30, 2014
236
I went thru the presentation and I am reminded very much of the three semesters of senior level courses in my engineering collecge 1969 thru 1972."Feedback Systems (1),Feedback Systems(2), and Feedback Systems(3)!
We DID learn how to accurately model a "Closed Loop Transfer Function", which in the real world we would evaluate how it ferformed in the particular application, and adjust it as required. Usually we came quite close initially. I DID need to bail out an associate one time who found that the calculated values did not work.
That education did provide useful insights on quite a few occasions but only a very few times did I need to use any of the math. That part of the education was also useful directly a few times.
Sadly, it seems that they shrinked/squeezed the course, so now there's just an introduction in every topic. It misses applying the knowledge in real cases, it's different from the exercises. I'm talking about my country, but I can smell that as many subareas were created, this implied in more subjects to learn in the engineering course, so others were left out because they were "less important".
Graduates now have to be much more like a polyglot than a specialist in one area, because jobs require now that you do one thing that's completely unrelated to what you did yesterday. What I happened to see is that the vast majority of people know how to code, but lack the knowledge of how circuits work, how components work, the physics, the math... Sad technological times.
 
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