LNK304 - ripple in power supply

Posted by: s0fighter on 01/31/2011

Hello,

I built a 12V DC supply using LNK304. Its producing the output nicely, although there is a dent on the waveform of about 200mV at 60Hz frequency. I am not able to remove this ripple.

I have tried using a voltage regulator, a voltage regulator with high PSRR and various capacitances. Can someone please suggest a solution to remove the ripple?

Thanks!
SF

Comments

Hello SF,

You need to post a picture with your schematic and/or the PIExpert design file.

Cheers,
PI_Crusher

Sorry. Picture attached.

-SF

Hello SF,

Make sure the input capacitors are capable to hold the DC input voltage higher than minimum required by the part. If necessary, increase C401 and C402 (or C402 only, you have to test).
Otherwise, if the input voltage is OK just check the current limit, se page 1 here:
http://www.powerint.com/sites/default/files/product-docs/lnk302_304-306.pdf
Fine tuning value of L2 could solve your problem if the maximum current is close to your requirements. Otherwise, you have to move to next power level and use LNK305.

Cheers,
PI_Crusher