Cell Phone instability issue for flyback converter

[malli_1729]

I have a flyback converter whose spec i am just giving at glance
Vac = 180 - 265
Out1= 12v@ 1.13A unregulated
Out2 = 5V @0.2A Regulated

I am using NCP1014 from Onsemiconductors. I have an issue when cell phone bought nearer to SMPS.

Whenever cell phone nearer to SMPS the 5V is becoming <2.5V approx
FB completely Open.

After switching oFF input and waiting for finite time(around 5 to 10sec) voltage is building UP.

Can any body suggest what's may happened...

 

[Genomerics]

That sounds like you have an EMC, Electro-Magnetic Compatibility, problem. I assume the phone is 'active' or 'transmitting' when this happens and, presumably, the phone is not being supplied by your circuit. Difficult one.

Beyond supplying appropriate shielding around the low level feedback points within the converter, or overall, then you may have to look at the general PCB layout associated with those paths and whether the addition of ground planes might help. Going off the deep end you may have a particular track with dimensions that act as a receiving antennae for the particular frequencies that the phone is operating on...

I believe FCC15 has some 'catch all' whereby if you experience such problems the solution is to 'move things about the place so it does not happen'.

Genome.