TOP269-JX - shutting down with transients

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I wonder if anyone has any ideas. I am using a TOP269-JX. It's application is a power amplifier. The board itself is capable of kicking out 90W easily, but when running at 25W and peaking to 40W it appears to shut-down and go into a restart mode.

Modifications I have made to the attached schematic have been to short R653 (I Limit at 100%) to no availe.

I have ensured that the control pin and bias windings and capacitors C630, C614 & C625 are tracked back to the bulk storage capacitor.

I have added 100nF across the pins Control to Source.

All to no availe.

I am starting to think that it is not the device running out of grunt during transienst as I fitted the meatier TOP271 with no sucess.

I am thinking it may be the feedback path that is to blame, but I would welcome any other suggestions from the experienced forum members.


PCAS837_PSU.pdf186.12 KB

check the output voltage and open C631 first. I guess it is caused by out of regulation.