Schottky diode failure

Posted by: itzbj on 01/13/2013

Well my secondary schotkky diode is getting short circuited when i am switching on my power supply at highest input voltage (66 V AC\DC).

Plz suggest me what should i do?

I have used same diode as per PI expert software suggestion.

What are the causes of this type of failure?

Comments

Use a scope and check for excessive voltage spikes at anode of schottky. you may need to add a snubber network such as series ferrite or amorphous spike suppression beads and or RC snubber across diode.

My power supply input is 85-265 V AC/DC and multiple outputs as mentioned below,

1)5V @120mA (Regulated winding),

2)22.5V @40mA,

3)-22.5V @40mA,

4)22.5V @40mA,

5)-22.5V @40mA.

I am using sckottky diode for all output MIC SS110 with peak inverse voltage rating 100V@ 1A rated forward current.

While switching on power supply one of the diode from unregulated winding get short circuited.

But problem occures only sometimes so plz suggest for the solution.

Still recommend looking at switching waveforms for excesives spikes at secondary winding of schottky. Schottky diodes in general are not a good choice for voltages above 12V due to spikes..