Other Parts Discussed in Thread: LM5155
HI,
Can you provide excel sheet of lm5155-q1 sepic circuit device selection?
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Hello,
Thanks for reaching out with you question and for using the LM5155.
Currently there is not a calculator available for the LM5155 in a SEPIC configuration. However the following application notes should help to calculate the power train components.
Please let me know if you have any questions.
Thanks,
Garrett
Hi,
Thank you,Garrett,
However, I have another question. In the LM5155SEPIC circuit I designed, when the current is 1A, the output voltage will have a voltage drop of about 1V. Is this a problem with the selection of MOS tube BQ1?
Condition: input 12V ,output 12.8V
I saw your feedback note is not at the output but inside. Can you monitor FB voltage if it is 1V? If yes, then the voltage drop is caused by your PCB trace resistance from the voltage sense point to the output port. To correct this, please move the R59 (? sorry I can for sure because of your schematic resolution) connection to the output port.
Thanks,
Youhao Xi, Applications Engineering
Attached are the connection method of R59 and the abnormal waveform of FB. My R59 is on the output port, but the abnormal waveform of FB cannot be kept at 1V. Is this the relationship of MOS tube?