Power Supply with DPA 424 getting reset

Posted by: sachindevassy on 11/05/2013

I designed a power supply circuit using PI software and DPA 424. The i/p voltage is 20-40 and outputs are 15V,0.1A and +-15V,0.1,5V,0.1 A. Instead of the suggested EFD25 flyback transformer core , I have used EE25 core.The rest of design is same.

I am attaching the diagram generated by PI .Now when i test the circuit with one of 15 V output ,others remaining open circuit; the output is 15V for a few seconds and then it gets reset as shown. There is also heating in the output diode snubber resistance. I am attaching the Drain source waveforms and Output VOltage waveforms .What could be the reason for this.?

Files

tek00008.png (37.11 KB)

Auxillary Power Supply.pdf (44.01 KB)

Comments

Hi,

Looks like the power supply entered to auto-restart. Open loop or over load conditions may exists for whatever the reason.

Would you please attached the design spreadsheet and transformer spec for further checking?

Thanks

Hi,

I am attaching the desing specs obtained from PI design software. The primary inductance of the transformer used is 30uH instead of 35 uH. The loading i kept for the isolated 15V output is 500ohms, the others +-15v and +5V was kept open.

Hi,

I did have a close look with the document that you attached, I did not find any obvious issue on it.

To figure out what exactly happened, would you please record the drain voltage and current together with the output voltage, and attach them? We may know what happen with this information.

Thanks