samson.bunty1986 Posted April 17, 2012 Report Share Posted April 17, 2012 Hi all,I have designed Sepic converter which can give output 24V,2.5A. In simulation am getting all correct values. I made PCB with that circuit. But now when i connect load my ouput voltage drastically dropping to 8V. Kindly help me out from thisThanks in Advance Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 18, 2012 Report Share Posted April 18, 2012 Apart from the fact, the circuit is wrong, you need to change C1 from an electrolytic to ceramic capacitor. Quote Link to comment Share on other sites More sharing options...
samson.bunty1986 Posted April 18, 2012 Author Report Share Posted April 18, 2012 Here is my circuit. How can you say my circuit is wrong?? Please suggest me..Thanks in advance24V_DC_DC_Converter.pdf Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 18, 2012 Report Share Posted April 18, 2012 Good, you've realised you won't get any help, unless you give enough information.Are you sure the simulation is accurate?Have you assumed ideal components?What about the PCB (which again you've not posted so we don't know)? Is it correct. Have you followed the layout recommendations of the SMPS IC manufacturer? Quote Link to comment Share on other sites More sharing options...
samson.bunty1986 Posted April 18, 2012 Author Report Share Posted April 18, 2012 Hi Hero,Thanks for you reply.In LT Spice i hve checked.. it is accurate. But now on PCB am not getting.Kindly suggest me about the Layout recomendation. I hope evry thing i made.Regards,Samson Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 18, 2012 Report Share Posted April 18, 2012 In LT Spice i hve checked.. it is accurate. But now on PCB am not getting.What I meant was are you sure the models used are accurate?For example, have you included the ESR of the inductors and capacitors? If the the answer is no, then your simulation is wrong. Quote Link to comment Share on other sites More sharing options...
samson.bunty1986 Posted April 18, 2012 Author Report Share Posted April 18, 2012 Ya..i have used all the parameters in simulation. The same components used on PCB also. Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 18, 2012 Report Share Posted April 18, 2012 How are we supposed to help you with the #pcb when you haven't posted the layout or a photograph?Is the PCB layout similar to that given on the datasheet? Quote Link to comment Share on other sites More sharing options...
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