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I am trying to design an AC/DC power supply for an LED aquarium light. My plan is to create a switching power supply which will first rectify the AC to a DC voltage before using switching to step the voltage down using a higher frequency transformer.

For the design of the transformer I have been mainly relying on three books.

Pulse Width Modulated Power Supplies by Valter Quercioli Switching Power Supply Design and Optimization Sanjaya Maniktala Switching Power Supply Design Abraham Pressman

In the future I might be interested in trying to sell this power supply as part of a product, so I am interested in ensuring that it operates safely.

At the moment my concern is should my power supply be designed to handle surges in the mains line due to lightning strikes? In all three of the books listed above no attention is given to this topic. I know that it is important to address inrush current to the capacitor, but I do not think any of these techniques would prevent current in the event of a lightning strike.

Based on the lack of information in these books and some information from other stack exchange threads Creating an isolated power supply to prevent effects of lightning I am under the impression that surges from lightning strikes is just something these electronics are not designed for. The main goal of this post is to first confirm that my impression is correct. Secondly I wanted to see if there are any best practices to handle surges from lightning strikes for indoor AC to DC power supplies.

Thank You

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    \$\begingroup\$ Just to add, if this is an actual commercial venture rather than an experiment in designing your own supply, it will be far cheaper, safer, and probably better to just get an off the shelf supply. AC/DC switching power supplies are used around the world, and ship in the volumes of 100's of millions to billions per year. I cannot imagine any scenario where your voltages/currents are such that you can't find an off the shelf supply. \$\endgroup\$
    – BeB00
    Commented Nov 22, 2019 at 2:23

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You're really asking the wrong question. If you're thinking about selling something that plugs into the wall in any volume, step back and figure out what the applicable UL standards are. There will certainly be some kind of surge test along the lines of IEC61000:4-5. There will be creepage, clearance, and isolation requirements. There will probably be a maximum acceptable temperature rise as well. If after figuring this out you still want to create a product, you would be smart to hire a consultant to review the design before going to UL for testing. This may cost a few grand, but failure will be even more expensive.

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  • \$\begingroup\$ Thank You for the input, I believe the device I am interested in created would be covered under the UL - 1310 standard for class 2 power units UL standard \$\endgroup\$
    – Cole Harlow
    Commented Nov 22, 2019 at 2:10

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