UL & Power Supply

Hello,

I am not sure I understand your question. Power Integrations is a semiconductor manufacturer specializing in high voltage AC to DC and DC to DC conversion. Our parts are not UL certified as they need not be since they do not bridge the isolation barrier from primary to secondary. More information about this is available here: http://www.powerint.com/en/forum/ask-pi-engineer/do-pi-parts-have-ul-csa-or-other-safety-agency-file-number

We do produce what we call "Reference Design Kits" that show how are parts are used in a complete power supply. These do not have UL certification but we have made every attempt to make them easily UL certified if someone wanted to produce this design.

I hope this helps to answer your question. If not please let me know and provide more specific information. Thanks!

Wesley

Hi Wesley, It was a general question. I designed a power supply by TNY275. I want to learn what I do for UL certification on the power supply board. For example clearance and creepace etc. Is there a document to be comformed for UL approval. Thanks,

Howdy y'all What you must do for UL as regards power supplies depends on your application. For pool and spas (me) it's brutal. In general: keep mains 3 to 6mm apart for 120V and 240V respectively. Keep mains and 30V separated by the same. The transformers for isolated supplies will need to meet certain spec's for creepage and air gaps, materials and the like. Make sure to take heat away. You don't need to meet UL if the customer doesn't demand it. I have a product that runs off 12Vdc at low current and I don't rate it.

Hi Erickson, Thanks for response, I designed a power supply input voltage 85-265. Output voltages 12,5,3.3 I understand from you I should apart mains 6mm.Primary and secondary also must be aparted 6mm. For transformer I used triple insulated wire.Is there any creepage for transformer? Thanks,

If you haven't worked with UL before you will need to determine what category you fall under and be prepared to spend money for their specifications. The specifications are hard to read sometimes. There are over-the-surface and through-air distances associated with transformers and all components that cross the high-voltage/low-voltage boundaries. Opto-isolators and FCC X1/Y2 capacitors will need to meet their spec's as well. Triple insulated wire is the solution you need. Transformer makers are going to be good at meeting UL. If you must meet UL then I would recommend: · Find the classification for the product and get the literature · Do your best to meet what you can understand · Open a project with them and make an initial submission (sample bare board and populated board, schematic, data sheets for all parts that you claim provide protection, and some information about your product's application.) · Be prepared to move quickly to resolve issues · Copy spacings of competitor products that have already passed UL · Keep your cool Chris

Sadik,

Erickson is correct about each step in the process of getting UL certification. Best of luck and keep us updated on your progress or any problems you have.

-Wesley