Perhaps it is an effect of the economy, but this year’s winners in the Best of Ideas for Design (IFDs) voting feature simple—almost trivial-looking—solutions to design challenges. The winner, “Use A DAC To Bias Your Varactor Diode,” didn’t even have a specific problem to solve. It simply provided design advice. The runners-up in the contest also show the value engineers are placing on simple, but not obvious, design ideas.
In his “Ten Cent Charge Pump Provides LCD Bias,” Bob Stevens shows how you can find a simple solution to a design challenge by stripping a requirement to its key elements. His project called for an LCD panel that required a higher bias than the rest of the circuit’s operating voltage. He could have used the standard approach of dropping in a charge pump converter, but did not want to pay the power penalty involved.
By recognizing that all he needed was a small voltage increase and very little current to give the LCD panel what it needed, Stevens was able to find his answer with a few diodes and a capacitor. The design itself looks simple and obvious in retrospect. It is the act of stepping outside conventional thinking to find the idea for the design that we admire.
The same admirable thinking is evident in Michael Gambuzza’s IFD, “OR Gates Slash Noise Coupling In Digital Potentiometer Applications.” In this case, however, the design challenge Gambuzza faced did not have clearly defined requirements. He sought a way to reduce the electromagnetic interference (EMI) coupling into a digital potentiometer without any specific metrics to guide him.
Gambuzza’s solution depended on recognizing two key concepts. One was that digital bus activity can be a significant source of noise. The other was that most of that bus activity is irrelevant to the digital potentiometer’s operation. By blocking all the irrelevant bus activity from the signal traces leading to the device, he was able to significantly reduce the opportunity for digital noise to couple into the sensitive analog circuits. Again, the cleverness involves the recognition of limited need. The device did not need to see all the bus activity, only the signals directed toward it specifically.
As simple as the winning IFDs seem when reading about them, there is nothing simple about creating them. Textbook and brute-force solutions to design problems are easy to come by. Simplicity and minimalism are attributes far more rare, and more valuable, in design. This year’s winning IFDs demonstrate those attributes.