Tiny switch is blasting while power on
Dear All,
I have designed an SMPS by using TNY 280PN as per Design Idea DI-152, specs are gien below
I/P Voltage : 85V - 265V AC & 32V - 72V DC
O/P Voltage : 5 VDC
O/P Load Current : 1.5 Amp max
Device Used : TNY 280PN
NO: layer PCB : Single layer
We have been observing some problem in our design that some of the units are blasting ( mainly TINY device) while power on.
Does anybody of you come to know these kind of problem any time , if so what will be the reason and what kind precautionary measures should be taken...???
Rgds
Hary
Comments
Dear ,
We have provided the RC shunt circuit as per the DI-152 description only.
Is there any problem in lay out..?? If you want I can send Schematic and lay out too you.
Also what kind of TVS we have to use , Can you suggest some of the samples which is matching for the same..??
Rgds
Hary
Dear ,
We have provided the RC shunt circuit as per the DI-152 description only.
Is there any problem in lay out..?? If you want I can send Schematic and lay out too you.
Also what kind of TVS we have to use , Can you suggest some of the samples which is matching for the same..??
Rgds
Hary
Hello Hary,
There are two main points you have to validate to avoid destruction of TNY280P. One is the input voltage; the second one is Drain voltage. TNY280 is well protected against over current; the best bet for catastrophic failure is over voltage. Check page 2 of the design example http://www.powerint.com/sites/default/files/PDFFiles/di152.pdf. The very first key design point is telling you how to deal with Drain over voltage measurement and protection.
One good way to identify the reason for loosing the power supply is to use limiting devices (like TVS) connected between the Drain and GND in order to limit the maximum voltage under 650V, or right at the AC input to make sure the AC line is not going too high. After you identify the source of the failure you have to adjust the clamp circuit or to protect against high AC line voltages.
Cheers,
PI_Crusher