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Requirements for an AC Power Adapter

Requirements for an AC Power Adapter

Requirements for an AC Power Adapter


I'm a mechanical design engineer by trade and I've started working on a side project for developing a special 120V AC to 5V DC adapter. Without going into too much detail on the design, I was wondering where I should be looking in regards to the regulatory requirements that this product will need to meet in order to be sold in the US as a power adapter. The product will have a NEMA-1 plug to attach to the wall and the output power will be 5V USB. The adapter is going to need to fit a very low profile envelope so I cant just use off the shelf components and most things will need to be custom designed including the transformer. Is there a code or standard that applies specifically to AC wall adapters that I can look over and make sure that our team is designing the product so that all requirements are met. More specifically I'd be looking at things such as casing strength, thickness, and insulation requirements, transformer requirements, durability requirements, etc. Also, what is the typical process for getting a product UL tested and certified? Anything to get me pointed in the right direction to start would be great.


RE: Requirements for an AC Power Adapter

UL/CE vert is what you're after. Considering the number of COTS products already existing that fit your description, you had best have some REALLY unique requirements if you expect to make money (and not lose a ton in the design process).

Dan - Owner

RE: Requirements for an AC Power Adapter

"...a special 120V AC to 5V DC adapter..."

Most are now universal input: 100-240 volts / 50-60 Hz.
(edit: Universality may balloon the number of certification marks required.)

Good luck.

RE: Requirements for an AC Power Adapter

Depends upon how wide a market you're looking at. There are energy efficiency requirements that may apply. You can't sell incandescent light bulbs due to government decrees, and with the cumulative power requirements of those wall-warts and standby supplies in our of our modern widgets the regulators have been busy legislating on those also.

You don't necessarily need a transformer anymore if your application is under a few watts. Browse the website of Power Integrations www.power.com There are other companies out there with similar transformer-less solutions for low power direct off AC mains. Above a few watts, a small flyback switch-mode power supply can be used and the transformers are small (design solutions also offered by Power Integrations, STM, NXP, Rohm, Linear Tech, TI, and many other companies).

RE: Requirements for an AC Power Adapter

UL60950 is likely the best place for you to start.

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