LNK302 with 220V mains supply voltage
Hi, I build LNK302 datasheet circuit but it didn´t work as expected.
First of all, the output voltage was 6V and not 12V? Could you know what I did wrong? Maybe a misplaced component or bad value?
Second, when I supply the circuit with 220Vac it remains the output voltage for a few minutes and after that the output is disabled.
I noticed that LNK302 is a little hot.
Thanks
Comments
About output voltage, I will check R1/R3.
The second issue I´m trying to understand is about full-range voltage input (90V-220V). When I use 127V input voltage the circuit works fine. When I use 220V input voltage the circuit works for 2 minutos and after that the output voltage drops down to 0 slowly.
Thanks again
It sounds like the device is overheating and going into thermal shutdown. You might need to increase the size of your PCB heatsink, go to a larger device or both.
-The Traveler
A quick/easy way to see if this is a thermal issue would be to take some copper foil (doesn't need to be too thick) and solder it to the source pins. This should give the device additional heatsink surface area to dissipate heat with. You could also use a can of freeze spray or something similar to cool the device.
-The Traveler
In Figure 5 of the LNK-TN datasheet, the resister divider R1/R3 sets the output voltage. You want to pick values of R1/R3 that produce a FB pin voltage of 1.65V. I would check your resister values to make sure they're correct.
I don't understand what you mean about running at 220Vac. Can you please rephrase your question?
-The Traveler