Revisiting this topic and paper came about because of some former colleagues asking questions about early work that was topic related to another former colleague, who joined us from a company very involved in Class D (Extron) and went back to them, and the curious tale of how I knew their research director long before this employee did, because of an AES presentation I gave and an invited paper that resulted from that presentation. Of course, it's about Class D design and development strategies.
I shared that with Sven this weekend, as he needed reading material on his flight back from India (I don't think this is what he was expecting, though!) and he suggested I create a post for it in case anyone else might be curious...
Keep in mind, this work was done WAY BACK before a lot of things we have and take for granted, including high speed computers and modern simulation tools and device models. All the simulation and development work was done on my personal home built 80386, which was blazingly fast and capable (32 bit!!) compared with what we had in the office for Application Engineers.
And I'll admit that it may seem a bit cheesy that I cited myself (in published papers) as a reference 5 times out of 19 cited references. But hey, prior art and all!
This presentation and publication got me a lot of interesting questions from the handful of other people active in class D development efforts. Sort of like making your own invitations...
The most curious and intriguing thing about re-reading this was noting in the power supply section (SMPS, not big transformers and caps) I had been developing what I called a ZVS-QRC, or Zero Voltage Switching Quasi-Resonant Converter, and I'll be dipped if that wasn't pretty much an LLC converter, using a special IGBT with fast switching and very low tail current losses, made lower with a half sine current profile this converter used. I don't recall LLC being a "thing" back in those days, not until the late 90s, though. And LLC analysis and design synthesis is what I focused much of my work on the last 5 years. My last work was an APEC professional education seminar on that topic, about 130 foils... drop me a PM if you have Apple messaging and I can send you the 50MB file. ;^)
OK, Peabody set the wayback machine to 1990!
Page 1.
I shared that with Sven this weekend, as he needed reading material on his flight back from India (I don't think this is what he was expecting, though!) and he suggested I create a post for it in case anyone else might be curious...
Keep in mind, this work was done WAY BACK before a lot of things we have and take for granted, including high speed computers and modern simulation tools and device models. All the simulation and development work was done on my personal home built 80386, which was blazingly fast and capable (32 bit!!) compared with what we had in the office for Application Engineers.
And I'll admit that it may seem a bit cheesy that I cited myself (in published papers) as a reference 5 times out of 19 cited references. But hey, prior art and all!
This presentation and publication got me a lot of interesting questions from the handful of other people active in class D development efforts. Sort of like making your own invitations...
The most curious and intriguing thing about re-reading this was noting in the power supply section (SMPS, not big transformers and caps) I had been developing what I called a ZVS-QRC, or Zero Voltage Switching Quasi-Resonant Converter, and I'll be dipped if that wasn't pretty much an LLC converter, using a special IGBT with fast switching and very low tail current losses, made lower with a half sine current profile this converter used. I don't recall LLC being a "thing" back in those days, not until the late 90s, though. And LLC analysis and design synthesis is what I focused much of my work on the last 5 years. My last work was an APEC professional education seminar on that topic, about 130 foils... drop me a PM if you have Apple messaging and I can send you the 50MB file. ;^)
OK, Peabody set the wayback machine to 1990!
Page 1.
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