My job is in automotive (buses, thus 24V, not 12V)

My usual statement "I know no engineer that does not know how to design a switching power supply, I know no engineer that can make one work" Is not reue any more since I had a meeting with an engineer from one of the power supply manufacturers.

Switching power supplies, that do not act as radio transmission jammers, overheat, burn on output shorts, occasionally let out a spike higher than supposed and more, is a job for the professionals.

We have here used 10.000s of a switching 24 to 5V supply an engineer spent 6 months perfecting. To solve a problem of interference in one location we replaced this with a circuit with a Power Trends nodule (PT6502) and the interference went away. We then realized that the failure rate (not just of the power supply, but also the circuits it supplies) dramatically went down from 1/500/year to a virtual zero.

We now routinely replace these 'homemade' supplies with the new PT based whether failure or not, it is cheaper to do so than to take the service calls.

Erik