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Texas Instruments still carries on Unitrode power seminar tradition

I recently attended the Texas Instruments 2018 Power Supply Design Seminar held in Phoenix, AZ. There were engineers from local companies from all around the Phoenix area in attendance that filled the hotel conference room. These engineers came to hone their power management design skills, many of them were not dedicated power designers, but engineers that needed to design their system power supplies.

There were about 35 or 40 attendees (I am not showing the back few rows in which I was sitting)

There were about 35 or 40 attendees (I am not showing the back few rows in which I was sitting)

Bob Mammano’s Unitrode Company began these seminars in 1983, starting with SEM100 in 1983 and then when Texas Instruments acquired Unitrode in 1999, they continued this much needed tradition with SEM1300 in 1999. When I was a circuit designer in the 80s, I attended these Unitrode seminars every year. Later when I joined Texas Instruments, I participated in some of the early seminars in the early 2000s as a field application engineer. I really like the way that the annual seminar content changes with the industry and also has a diverse set of topics that greatly help designers. This year’s Power Management design content that I found most interesting was as follows:

1 Topic: Survey of Resonant Converter Topologies. My former TI colleague, Brian King presented this section.

What I liked: First, the classic resonant topology was shown and then we looked at the LLC Series Resonant Converter topology (LLC-SRC) and discussed Circuit linearization with a ½ bridge chock full of useful mathematic equations and graphs, which are generously used and discussed throughout this seminar. Soft-switching in a Resonant Topology was also discussed in depth with the input/output voltage gain using a sinusoidal input to the 2-Element and 3-Element L and C combinations showing the best and optimum L/C combinations of LCC and LLC passive components.

A classic LLC Series Resonant Converter (LLC-SRC) (Image courtesy of Texas Instruments)

A classic LLC Series Resonant Converter (LLC-SRC) (Image courtesy of Texas Instruments)

2 Topic: Effects of Real Life Parasitics/Parameters.

What I liked: We looked at an ideal vs. a Real transformer with parasitics for the components like the L and C’s used, non-ideal switches, and finally, the benefits of Wide Bandgap Devices for a Resonant Converter.

3 Topic: Control and Design Challenges for Synchronous Rectifiers (SR)

What I liked: This was an extremely educational section with various SR control methods and design challenges with options in choosing the SR MOSFET and also operating in Continuous Conduction Mode (CCM), looking at noise optimization, bias, EMI and so much more.

4 Topic: Comparison of GaN and Silicon FET-based Active Clamp Flyback Converters.

What I liked: We analyzed adapter density and efficiency comparisons and also looked at passive and active clamp modes including Active Clamp Flyback (ACF) in a detailed analysis.

5 Topic: Power Solutions for Class D Audio Amplifiers.

What I liked: Crest Factor and Speaker Impedances were discussed. Audio degradation was analyzed and then we looked at the AC/DC Power Supply and an Automotive Power Supply for Audio design.

6 Topic: Common Mistakes in DC/DC Converters and How to Fix Them.

What I liked: This was one of the best sections. We were given 10 problems with graphs and equations and asked by the presenter to explain what was causing the particular problem and how we could fix the circuit.—This was so much fun and highly insightful and educational with some really neat subtle and intricate problems encountered in real circuit design.

7 Topic: Introduction—Loop Gain Overview

What I liked: This was perhaps the most insightful section for which most designers do not have an in-depth understanding. I learned a great deal from this section, especially how to properly measure Loop Gain in an Open-Loop setup. Actual bench setups were outlined in this section.

I will not give away all the details, but you can go to the seminar near you next year (I highly recommend that) and for now, if you missed this year’s seminar, you can visit the TI Power Supply Design Seminar—2018 Materials page and log in for the presentation materials and white papers. All engineers who need to design power supplies, especially those who are not expert power designers, need to have this material as well as the simulation software like TI’s Power Stage Designer and WEBENCH.

5 comments on “Texas Instruments still carries on Unitrode power seminar tradition

  1. bcd_testech
    May 2, 2018

    Greatly appreciated. I attended one of the SEM500 sessions back in (gulp) 1987 and was super impressed by the methodical approach to numerous topics, such as transformer wire temperature, that I'd viewed as half rule-of-thumb, half black magic. I had no idea TI was still holding the seminars, much less that the material would be available online.So your article is nearly as much of an eye opener as the original seminar.

  2. Steve Taranovich
    May 2, 2018

    Thanks @bcd_testech—I highly recommend these seminars because of the in-depth educational value they provide to designers, no matter the level of experience they have. The presenters are experts in their own right as well. I always learn things from these kinds of excellent seminars.

  3. sby
    May 2, 2018

    I have attended a number of Unitrode seminars in previous years. One time I sat beside Lloyd H. Dixon, one of the major contributors of the early seminars and author of many papers that can be found in the seminars booklets. At that time, I was, and I am still, very much impressed by Dixon's ability to bring up the gist of the matter in an intuitive way without wearing out the reader with pages and pages of equations. While chatting with Dixon I have complemented him on his very clear and reader friendly papers. He responded in saying something like: ” I see as my duty to explain what is written in all these journal papers”. For many years now, I have adopted this intuition-based-knowledge approach and I believe that my students and readers of my papers benefited from that.

     It is indeed good news that TI is continuing the tradition of the power electronics seminars to the benefit of the engineering community. 

    Sam

  4. D Feucht
    May 7, 2018

    Indeed, Lloyd Dixon deserves being inthe E.E. Hall of Fame, if there were one.

    He has derivations of equations in some of his articles, but it has been left to me and others to bore the reader with a multitude of equations. When I do it, I try to indicate which are the useful design formulas so that math-averse readers can scan past the derivations and read how to apply the resulting formulas.

    And for those who want a deeper understanding of where the equations came from and how they came about, the derivations are there. I encourage this deeper understanding because design formulas can be misused as a consequence of not knowing the conditions under which they apply or exactly how they apply. And for those wanting to Lead the Field in E.E., depth at both the desk and the bench are required to understand how clear theory and real circuits relate.

  5. RituGupta
    July 23, 2018

    Tradition can only be practiced when it is deemed as successful. If those who practices it feel that it is not worthy of their time and effort, then it would probably have been banished many years ago. This goes to show the success rate of this tradition that it can be sustained for a long period of time. This isn't something that can be done overnight, but requires a lot of commitment to be achieved.

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