Switching power supplies can offer much better efficiency than linear supplies, but they’re also a bit trickier to get working and require more components and more precise component selection.  How do you evaluate switching more power supply circuits?  In reality there are a lot of parameters to test often requiring specialised equipment — things like a DC load to test efficiency, special probes for your scope, etc. — but there’s a good article at Scope Junction on the topic: Stability Testing A Switching Power Supply.

The articles assumes you have access to some fairly high end equipment (a network analyser, etc.), but it’s an interesting read just to see some of the real world considerations that you need to keep in mind with commercial design and how much testing really goes on (or should go on) in the manufacturing process.

Some manufacturers do this better than others.  I have vivid memories of working as an apps engineer being tasked with helping a Japanese company using a brand new and complex MCU in their product.  Every time I saw an email from them in my inbox (daily) I winced because I knew it would be another incredibly precise question involving very specific values or test conditions and I’d have to call up the chip design team to get the test parameters and see what was up … it was never much fun, but it did instill in me a lot of respect for the testing efforts they went through, and sometimes they were right and identified one or two issues that got past the validation team MCU side.  It was a wakeup call for everyone, but a good one.  Testing matters, and often testing can be as much or more effort than initial product development.

Have any horror stories where you wish you had put more effort into testing yourself or had to compromise because of deadlines and it ended up biting you in the back-end?  Post them up in the comments below!