LNK625 IC Blowing and no power supply
Hi!!
I have assembled a design generated by PI expert on a breadboard. Circuit diagram attached. It is supposed to convert universal AC to 12V dc with power rating of 800mA.
The design worked very stably in the first attempt to generate 16V. This was expected since the feedback resistor was of slightly lower value then required.
The transformer was made by me and I have tested it on a scope by exciting with a function generator of 100kHz SINE wave and the reduction in voltage seems to be accordingly to the expected turns ratio ie ~ 10:1
However the circuit does not seem to work ever since I have assembled it again.
Keeping the circuit on for less than 2 minutes causes the LNK625PG to blow (literally) along with L1 and L2. I have used 1N4007 instead of fast recovery 1N4148 on the breadboard.
The most puzzling part is why would the circuit not work in the second attempt. I guess some stray might have influenced it but any pointers would be very useful.
I have already blown up my 2 LNKs. Any pointers please
Regards
SM
Comments
Hi,
Testing on bread board is very unreliable. If one of the component deos not make proper contact, there is a very good chance that the power supply can get damaged. For example if the primary clamp circuit doesn't make proper contact with circuit, then primary MOSFET can get damaged easily.
I would strongly recommend you to design the PCB layout and assemble components instead of assmbilng it on a breadboard.
Regards,
PI-NANO
I am also facing same problem with this IC on 2 -3 boards and blown 5 ICs. Can anyone pls help us to find the solution.Design is attached here.
| Attachment | Size |
|---|---|
| LNK625 design.PNG (35.85 KB) | 35.85 KB |
Hi,
This is someone else's post, if you have a question please post it seperately.
What exactly is the problem on your power supply?
Can you please send me your PIExpert design file and PCB layout?
Regards,
PI-NANO
I have checked with a scope across LNK and seems it is not switching at all