Power Supply Choices

Unless you are building a crystal radio or you’ve finally invented that infinite energy machine, any project you do is going to need some sort of power supply. There was a time when a battery was enough, but these days you probably need some sort of regulation. But there are many kinds to choose. Linear, switching, SEPIC, LDO… how do you pick? [Andreas Spiess] has some practical advice in his recent video, which you can see below.

[Andreas] calls the video “Voltage Regulator Cheat Sheet” and that’s an apt name. He covers the major architectures and even points out why you can’t always trust the vendor’s information on certain types of supplies.

Even though it is billed as a cheat sheet, the video also covers a good bit of theory on how the different regulators work and their efficiency and thermal characteristics. He punctuates his theory with practical demonstrations, as always. He even releases a little magic smoke in the name of explaining things.

If you want to look inside a linear regulator, we saw a good teardown of the venerable 7805. We don’t suggest it, but the next step up from the resistor [Andreas] shows is a zener diode, a topic we covered last year.

6 thoughts on “Power Supply Choices

    1. It’s a good thing to worry about, and so easy to accidentally get wrong. e.g. “hey, MLCCs are pretty cheap, I’ll put some on an LM317″… which is good if what you really wanted was an oscillator.

        1. Start with the datasheet – they will tell you if you should / should not use MLCC. If it can’t handle the low ESR, you put a small value (10R range) resistor in line with the ceramic to give it some damping against ringing.

          But yea, every linear and LDO linear I’ve used recently have all called for or accepted low-ESR / ceramic caps. Or didn’t require them at all.

  1. Liked it. Good general overview. Not too technical and roasting resistor gave impact. Accent a bit much for me. My problem. Accentual pauses like chalk scraping for me. Subtitle so can be translated to other languages and other reasons. Nice start of a library. Like to see more.

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