GUI – A Crutch or an Aid?

Apr 18, 2007 11:08 AM
By Lou Pechi, President, STRATA Strategic Advisors, San Diego

We have all heard that in order to sell a new power control or converter circuit, one needs a well-designed graphical user interface, commonly called a GUI. So, what has happened to the old Bode plots, loop stability calculations and the Venable instruments with their gain frequency displays of loop gain and phase shift versus frequency. Have the designers gone soft on us and lost their ability to design without the proper software?

While I nostalgically reminisce about the old times, I don’t miss the days when I practically wore out several slide rules, punched innumerable buttons on the red LED HP calculator, and modeled dc, ac and transient circuits using the slow GE Teletype circuit analysis programs.

Designing a power supply in those days required hard work. There were no ready-made ICs, and one had to design saw-tooth generators, one-shots, stable reference voltage circuits and differential amplifiers with discrete transistors, resistors, inductors and capacitors.

Computers changed all of this. Any designer worth his salt has been using the available circuit analysis and modeling programs like SPICE and a plethora of other acronyms for years.

The history of the GUI goes back to Doug Engelbart and his team at Stanford Research Institute, who used text-based hyperlinks manipulated by a mouse. The concept of hyperlinks was further refined and extended to graphics by researchers at Xerox PARC, who used a GUI as the primary interface for the Xerox Alto computer. The GUIs familiar to most people today are the Macintosh, X Window System or Windows interfaces.

While such GUIs have become ubiquitous for the general population, power-supply designers have — until recently — shied away from such programs when designing power supplies. It seemed that analog design and a digital GUI were like oil and water, and did not mix. But the shift to digital power conversion, and particularly digital control, was the catalyst that allowed the GUI’s acceptance by the power-supply engineering community.

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© 2007 Penton Media, Inc.