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[SMPS failure]

Posted by: Geek12 on

Hi, 

 

I have a SMPS design where i use TOP244 switch with an BZG03C200 and an ES1J as a snubber diodes. 

Recently one SMPS was returned with the two diodes (ES1J and BZG03C200 ) are damaged.

Upon replacing the two faulty components, it started working.

But i am unable to understand what might have caused this failure when there are overvoltage and overcurrent protections present in the lines? Is it some problem with transformer and its leakages or problem of snubber diode?

Can anyone please explain what could be the root cause?

Please advice.

 

Thanks.

Geek12

Comments

Submitted by PI-LeoDavinci on 06/30/2017

Hi Geek12,

Thank you very much for using Power Integrations product particularly the TOP244. With regards to your inquiry may we ask if you have a schematic and the a captured waveform of the failure particularly showing the drain to source voltage. However some basic things that you can check/verify are the following:

1. Your snubber circuit must be properly rated. The rating will depend on how much voltage is imposed during the snubbing time. You may want to check the drain voltage spike at light load going to full load but just make sure that the peak voltage does not exceed the rating. Do the loading slowly and observed the peak voltage.

2. Measure the leakage inductance of the transformer and make sure that this is minimal in as much as the coupling must good enough.

Hope this helps.