The Basic Design Cycle in Electrical Engineering
Circuit boards now have circuits as tiny as 0.1 mm, about the diameter of a human hair. That's one reason humans don't solder chips onto them. But rather than physically make the signals, it's more important that today's electrical engineers understand the subtleties of sending very high speed signals through these signals.
Some designers work with transistors to build integrated circuits like microprocessors and digital signal processors. Millions of these elements are often combined on a single chip. Other engineers link these semiconductors to other components, resulting in circuit boards that make the magic of cell phones, computers and other electronic gear a reality. Still others work at larger levels, bringing to fruition computer networks, cell phone infrastructures and other complex systems that seamlessly combine many different products together.
Some basic designing tasks remain similar across the board. But specific electronic products demand varying design objectives. For defense and automotive applications, a product's ability to withstand a harsh environment is key. Low costs drive consumer applications. For portable equipment, size and battery lifetimes are paramount.
Given these different parameters, electrical engineers ultimately determine how products will perform. An engineer must know how to tailor a product design to meet these varying requirements. Bosses don't expect new graduates to understand these nuances, but young electrical engineers need to pick up these traits quickly to become important players on a design team.
Engineering generally starts with conceptualizing, in which the general ideas about a new product are sketched out. Sometimes the idea springs from one person, but more often, teams of marketing and manufacturing personnel sit down with engineers to determine what customers want, and what they can efficiently build.
Once the concepts are firm enough, engineers start figuring out the circuitry that will enable a given product to accomplish the desired tasks at the necessary price and performance points. This is the mainstay of electronic engineering, the primary daily responsibilities of most engineers--turning marketing goals like a product's size and performance into actual working circuitry.
To do this, team members must figure out the overall approach, often called the architecture. This is the "back of an envelope" approach often described for young startups, in which someone grabs some scrap paper and starts showing others how their concept will work.
The architecture is much like a blueprint, in that it shows only the overall plan, not the actual size of a nail or the speed of an electronic component. Often, the architecture is derived from previous generation products, or it may be based on a standard such as PC architecture.
Today, designs are typically completed on PCs or workstations, which are more powerful computers that can handle the complex drawing and mathematics needed for designs that can have millions of individual elements. Computer-aided engineering and design programs are the common tools of the trade, along with oversized monitors that make it easier to see the many fine lines in most products. Many engineers say that these CAE and CAD programs make it seem like they're building a product using Tinker Toys.
But constructing electronic circuits is anything but child's play. There are subtle nuances in the way components fit together, and a single error in a large system can hinder performance or even cause a complete shutdown.
CAE and CAD programs now accomplish many of the mundane tasks engineers used to have to do themselves, such as routing the signal lines that link components together on a circuit board. In that instance, determining which components are needed would be the first step. The architecture defines some parameters, but engineers would then figure out which parts do the job efficiently. Specifics like speed, power requirements, cost and component availability are key parameters. Engineers have to understand technical tradeoffs, but they must also be able to anticipate whether new parts will become available in the time they need, or whether older parts will become obsolete before their creation is produced.
Arranging these components is the next step. Engineers must consider several factors. Chips that generate heat need to be separated from each other, so that it's easier to cool the system. Electrical noise must also be taken into account. Just as a cell phone or vacuum cleaner might cause static when it's too close to a radio or TV, electronic parts can interfere with other chips' performance if they're too close to a sensitive device.
Once all of the pieces are properly placed, it's time to start checking the function of the overall design. For this, engineers turn to other development tools called simulation and verification programs. Even if the design exists solely on the computer at this point, simulation programs can anticipate how the virtual circuit will work. They can tell if the design actually does the jobs it's designed to do, and how quickly it accomplishes its objectives.
This can be a lengthy process. Engineers run the simulation, then pore over the results to see how the product is performing. Sometimes, they're looking for bugs that prevent the system from working efficiently. Other times, they're thinking about ways to improve the design's performance. When they finish one round, they often run another simulation, repeating this cycle until the design seems perfect.
Once tweaks and fine tuning have been done, verification software performs another round of tests. Often, hardware and software are verified together in this phase. Software is a critical part of any design, and the way hardware and software work together is crucial. During this phase, EEs will work closely with programmers to weed out any glitches.
All these computerized examinations are usually performed before an actual physical prototype is manufactured, as it's far cheaper to spot and fix problems before real hardware is put together. In the semiconductor world, it's not uncommon for chip designers to iron out most major problems before the first silicon prototypes are produced.
Even though design tools are able to accomplish more and more of the steps in product design, it's still critical that skilled workers are on hand to interpret the results of these programs, especially as products continue to grow in complexity.