Hello!
I am developing a sensor-centric design which will need to run off mains voltage. Its going to be an "install and forget" solution and its installed in regular wall outlets. I have plans to commercialize it but that's long ways down the road. For now, I am at the concept stage.
Naturally, this sensor and the supporting circuitry needs power (i budgeted around 5W @ 5VDC) and it can be derived from AC mains source. I am located in the US but decided to accept universal ac input range (85 to 265VAC) at 50/60 Hz. I have already decided on the SMPS IC (with integrated SW) i plan on using and have figured out that UL60950-1 would apply to me. Since this has become an ac/dc converter, I will need a high frequency transformer to process the power (flyback topology) and have done back of the envelope calculations for the specification.
So, with this stated, here is why I am posting here:
1- Has anyone ordered custom split core transformers (or even COTS transformer) from China (through alibaba)? If so, how did you got about preparing the technical datasheet such that the end product conformed to the safety requirements for the UL60950-1.
As an example, how did you specify the insulation requirements for the transformer? Did your chosen production house already know what insulation and how much of it to use etc.
2- I'd be happy to outsource this SMPS design to a design house in china (i'll give them PCB outline etc) but so far, I have not been able to find a design house. If anyone has any idea how to go about it, i'd be more than happy to go that route.
Designing a SMPS processing mains AC into DC isn't exactly a complicated exercise but creating specifications for the transformer and having a production house in china conform to it is challenging, especially when you're sitting on the other side of the world.
Any response addressing 1 and/or 2 is welcomed!
Thanks!