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Power Integrations Engineer Power Integrations ModeratorDER 192 problem
Hi,
I have built the DER 192 non dimmable power supply, and this design does not work properly. There is no change between the application note and my board. The generated current is about 400 mA and not 330 mA. I already try to change the R7 value, and the current is still too high. Where is the problem ? Can I change the value of R11, R3 and R4 ?
Thanks in advance for your help,
Best Regards,
Vincent
1 reply | Created on Aug 31, 2010 23:32 PM by woazim
woazim
You may have some noise on the FB Pin. Try attaching a 1000 pF cap to the BP Pin and the Source pin. Also make sure that T1 is not saturating by looking at the Drain current with a current probe and scope. The current ramp (with pedestal) should be a straight ramp (not curving upward). If the current needs to be reduced, try increasing the value of R7.
Z. Cochrane
John Carpenter | 297 posts 