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Early Analog Insights: By Professor R D Middlebrook

In the following slideshow, I will present some pretty amazing in-depth analog concepts by the renowned Dr. R D Middlebrook, one of the early experts in the field of Power Electronics. His insights in creating state-space averaging methods and other concepts for analysis proved so important to our present day power electronics designers. On Slide 5 you will see that paper by Middlebrook and Cuk that led to the patent for the Cuk DC/DC converter.

Also, see my 2012 article on EDN entitled How Dr. Middlebrook shattered analog paradigms

All of the white papers referenced in the following slideshow can be obtained on the IEEE XPlore website . Those interested will need subscribe in order to access these historical tech documents.

Click on the slideshow image below to begin the slideshow and to see some insightful early feats of engineering concepts by Dr. Middlebrook:

Click here for larger image 
In 1956, Professor Middlebrook, while at the CalTech, Electrical Engineering Dept., Pasadena, CA, derived a new approximation for the frequency dependence of the short-circuit current gain of a theoretical junction triode along with R.M. Scarlett from the Stanford University, Electronics Research Lab, Stanford, CA (The Bipolar Junction Transistor was only introduced four years prior). In the images above, we see the equivalent circuit of a junction transistor and in the graph below it, is shown a comparison of the transient response of alpha for values of o.80 and o.99 The derivation was a rational function of frequency and easy to use. He showed that the approximation was in almost perfect agreement with the frequency response of the theoretical expression for alpha in both magnitude and phase all the way past the alpha cutoff frequency. (Image courtesy of An Approximation to Alpha of a Junction Transistor, R.D. Middlebrook, R.M. Scarlett, IRE Transactions, Electron Devices, 1956)

In 1956, Professor Middlebrook, while at the CalTech, Electrical Engineering Dept., Pasadena, CA, derived a new approximation for the frequency dependence of the short-circuit current gain of a theoretical junction triode along with R.M. Scarlett from the Stanford University, Electronics Research Lab, Stanford, CA (The Bipolar Junction Transistor was only introduced four years prior). In the images above, we see the equivalent circuit of a junction transistor and in the graph below it, is shown a comparison of the transient response of alpha for values of o.80 and o.99 The derivation was a rational function of frequency and easy to use. He showed that the approximation was in almost perfect agreement with the frequency response of the theoretical expression for alpha in both magnitude and phase all the way past the alpha cutoff frequency. (Image courtesy of An Approximation to Alpha of a Junction Transistor , R.D. Middlebrook, R.M. Scarlett, IRE Transactions, Electron Devices, 1956)

1 comment on “Early Analog Insights: By Professor R D Middlebrook

  1. DLA
    June 23, 2017

    I took his seminar about 20 years ago. The extra element theorem (EET) technique is very useful. It allows simple analysis of an initially simple network, but which then adds an element. Example – a twin-tee type circuit – adding one circuit element often makes the analysis much more difficult. Middlebrook developed a simple formulaic method to simply modify the result from the simpler network to account for the added element – instead of having to write and solve complex mesh KCL/KVL equations. 

     

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