mathos00
Newbie level 2
Hello,
We have designed and tested a number of small (10-20W) non-isolated buck converters for us in LED lighting products. They work well, and have proven exceptionally efficient.
Though some serious heavy weights in this area, such as Ron Lenk and Steve Winder, have developed such supplies for use in LED products, I'm left slightly with the jitters.
It is a new area for us, as much of our team is in Korea, where they simply don't do non-isolated supplies, as they are apparently not allowed.
The potential liability issues are huge, not to mention killing people is usually considered a bad thing for a product.
Given that LED products, ours included, are built on MCPCB materials (aluminum), you don't have 1.5mm of fiberglass to isolate the PCB board from the metal housing of the fixture.
The isolation of the mains voltage from the case, and thus from the end user, boils down to the dielectric material of the PCB.
From our knowledge, these materials are something like 1.3kV/mil.
At 3-5 mills for the thermally conductive dielectric materials commonly used in the industry, this would seem to imply a good 3.5kV or more for breakdown voltage.
Anyway, the simple question is can such supplies really be considered safe in this type of application?
Much better designers than I seem to think so, but would really love to hear the thoughts of others on this.
Thanks!
We have designed and tested a number of small (10-20W) non-isolated buck converters for us in LED lighting products. They work well, and have proven exceptionally efficient.
Though some serious heavy weights in this area, such as Ron Lenk and Steve Winder, have developed such supplies for use in LED products, I'm left slightly with the jitters.
It is a new area for us, as much of our team is in Korea, where they simply don't do non-isolated supplies, as they are apparently not allowed.
The potential liability issues are huge, not to mention killing people is usually considered a bad thing for a product.
Given that LED products, ours included, are built on MCPCB materials (aluminum), you don't have 1.5mm of fiberglass to isolate the PCB board from the metal housing of the fixture.
The isolation of the mains voltage from the case, and thus from the end user, boils down to the dielectric material of the PCB.
From our knowledge, these materials are something like 1.3kV/mil.
At 3-5 mills for the thermally conductive dielectric materials commonly used in the industry, this would seem to imply a good 3.5kV or more for breakdown voltage.
Anyway, the simple question is can such supplies really be considered safe in this type of application?
Much better designers than I seem to think so, but would really love to hear the thoughts of others on this.
Thanks!