Viper28 voltage drop under load

aquamoon · ‎2015-05-07

Posted on May 07, 2015 at 19:14

Hello

I built a SMPS using the eDesignSuite. It is based on a Viper28, and was designed to output 15V 750mA from 80-265V AC. I wound my own transformer based on the specs from the design. Under no load the output is 14.4 volts. Under load the output drops to 12.5V. I have attached my schematic, the st schematic and tx design and my pcb layout. Does anyone have any ideas as to what could cause this?

Thanks

#viper28 #edesignsuite

ramator · ‎2015-05-09

Posted on May 09, 2015 at 20:33

If the feedback circuit is faultless it means that the lack of power at the output associated with the improper design of the transformer. It should be practical measure inductance of the primary winding and control the absence of a magnetic saturation. The secondary winding is better to place between the two sections of the primary winding.