Mark Wyman

Principal Engineer at Vanteon Corporation

Expert in many aspects of electrical engineering with embedded systems. Lets summarize one of my successful projects without giving away a bit too much: Recent one... 10KW DC to DC power supply design: * The processor code for signaling and control, PID loops, etc. Using the Analog Devices CM419 (relative to the CM409, but dual core). This in itself is a dissertation for so many reasons. Ask me some time. * Multi-phase Delta-wye topology. 3 full bridges and 3 synchronous rectifiers work together. Yikes. * Specialized layout and design for high current support to remove busbars. 5oz copper per side of PCB. * 3D modelling of entire system * Testing and qualification of requirements. * Dealing with the problems of standard silicon FETs and moving to SiC devices (wow, that was an exciting change!) * Project lead on this one. This is a short summary, trust me, this makes it seem easy. The above is in the final stages of development. One of the greatest challenges here was the magnetics design, of which we had a lot of help with as this is not my specialty. Usually this can be accomplished off the shelf, but not on this design! This design uses soft-switching, which is also known as phase shift. The advantage is you don't have to deal with snubbers, large voltages, and a pile of harmonics. The disadvantage is the huge circulating currents and inadvertent FET switch-ons due to Miller effect from other phases in the system. This caused the transformer design to be "interesting" as it required a large amount of leakage inductance to behave more like a resonant converter. In the end it required a very large external inductor in series with the primary to take the current, but this provides BEAUTIFUL waveforms. Almost sinusoidal with high efficiency. Those little Miller effect problems age you quickly at this power level though. Learned early on the standard high power low Rds on nFETS were not suitable for this design. Some things I am very comfortable with involve crazy PCB layouts, cost effective ideas to avoid over-engineering, practical solutions to solve problems, getting to the bottom of difficult problems, and fast turn around from concept to delivery. I love working on all aspects of a design, and enjoy "owning" a design in that I get passionate about giving my best to deliver excellent results. I have a lot of experience in many areas of embedded design, and enjoy a good challenge.