For aspiring electrical engineering students trying to decide what to specialize in, I strongly encourage considering power electronics. Every new electrical or electronic product needs a power supply – talk about job security! Despite what you might think, the field is full of challenging work and opportunity for innovation, driven by the quest for smaller devices and higher efficiency.
It may not be as sexy as being a digital designer. But if you decide to take the path less traveled, you’ll be rewarded with challenging and innovative work, and eventually find yourself in a tightknit community of digital outcasts.
Power-supply designers are a different breed. Yet there are common threads that weave through the fabric of the power community and bind us together.
You might be a power-supply designer if ...
1. … you brag about your low IQ. Forrest Gump taught us that a low IQ isn’t necessarily a bad thing. Of course, in power supplies, IQ refers to quiescent current – not intelligence quotient – and it can draw some strange looks from anyone eavesdropping on a conversation. Power-supply designers are always trying to reduce their IQ in order to extend battery life and improve efficiency. This is particularly important with low-dropout (LDO) linear regulators. At TI, we are proud of our portfolio of low-IQ LDOs, which enable designers to prolong battery life and performance in their systems.
2. … you keep retelling the same story involving an erupting capacitor. We’ve all been there. Whether it was due to soldering the capacitor into the circuit backwards, an overvoltage condition or too much ripple current, nothing will draw a crowd to your lab bench faster than the sound of a capacitor popping.
After your pulse rate goes back to normal and the cloud of magic smoke clears from the lab, it’s natural to admire the awesomeness of what just transpired. Don’t be ashamed to share vivid details of your impromptu fireworks show with your peers. We won’t judge, and will happily reveal tales of calamities past. Always use your protective eyewear, people!
3. … you’ve ever searched Wikipedia for the truth table of a simple logic gate. If you don’t use it, you lose it. After working in the analog world of power-supply design for over 20 years, I have lost touch with the realm of 1s and 0s. Whenever I struggle with a digital circuit, I pull out Figure 1, which I found in a fortune cookie many years ago. It calms my nerves and allows me to focus on the problem.
Figure 1: The most perfect fortune cookie fortune ever
Digital control of power supplies is more common now than when I began my career. If you need help with designing a digital power supply and don’t have a fortune of your own, TI offers a plethora of digital power products and resources that offer flexibility, efficiency and integration so that you can meet your dynamic system needs and reduce your total cost.
4. … you’ve ever had to explain that perpetual motion is impossible. If you design power supplies long enough, at some point you’ll be asked to create a power supply that delivers more output power than what’s available from the input source. It’s amazing how difficult it is to convince some people that this violates the first law of thermodynamics (energy is neither created nor destroyed). The next time you are faced with this dilemma and want to be bold, you could simply ask rhetorically, “So, you want this power supply to be 110% efficient?” And if that doesn’t work, try asking them what is wrong with Figure 2.
Figure 2: Infinite power
Of course, the most sensible response is to renegotiate the power requirements of the input, the output or both – and then design with TI’s highly efficient DC/DC switching regulators to deliver the most power possible from a limited power source.
5. … you’ve ever told management that they can only meet two out of three goals. The old saying “two out of three ain’t bad” definitely applies to power-supply design. Of course, I’m referring to the three trade-offs of cost, size and efficiency, which unfortunately, your manager or customer may not fully grasp.
You can make a power supply smaller and cheaper by switching at a higher frequency, but that will make it less efficient. You could keep it small and make it more efficient by using better components, but that makes it more expensive. Or you could make it more efficient and cheaper by using larger components. Sorry, but just like everything else in engineering, nothing comes for free. Good luck explaining this to your manager!
6. … you speak in a language only other power-supply designers understand. Like siblings who have spent way too much time with one another, over time, power-supply designers tend to develop new words to communicate among themselves. To the outsider, this will sound like nonsense, but to the power-supply designer these are highly technical terms.
For example, a common conversation that may occur between two power supply engineers could sound something like:
Power engineer #1: "After a 30-minute cold soak, my choke was singing."
Power engineer #2: "Try changing your caps from lytic to poly to keep your zero from sliding!"
7. … you count the days until the next Power Supply Design Seminar (PSDS). The PSDS has been the premier industry-led seminar for practical power-supply design since the 1980s. Every two years, we hit the road to bring training directly to you, with new content that has been carefully screened to be useful, educational and interesting.
Whether you’re new to power-supply design or have been designing switching power supplies for decades, the PSDS has something for everyone. It provides a chance to learn something new, get a refresher of the basics, and connect with others in the power-supply community in your local region.
Over the decades, Unitrode and TI have created a treasure trove of reference material for power-supply design, all of which is free to access. The show continues with the 2020 PSDS beginning soon – you can register here.
If you’re new to the power-supply community, welcome to the secret society of power-supply designers! If you already identify as one of us, please share your stories and other signs that “you might be a power supply designer if …” by commenting beneath this article.
For all of you, I look forward to connecting at the 2020 Power Supply Design Seminar.
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