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LM3481: LM3481MM/NOPB

Part Number: LM3481
Other Parts Discussed in Thread: TPS61288

Please review the design ,

I want 12 V 2A of the output charge.

My system will provide input of 3.6V of voltage.

Please let me know if any updates.

  • Hi Tirthal,

    the expert supporting LM3481 is out of office until first week of the 2021. He will reply the question after back to office.

    however, the TPS61288 should be better solution from efficiency and solution size from input/output condition.

  • Thank you Jasper!

    Hi Tirthal,

    Sorry for the delay. As Jasper recommended, the TPS61288 seems to be a better solution.

    Anyway, regarding your schematic, it basically looks good.  A few points to consider

    • R18=2.21k appear to be too small, which sets the switching frequency >2.7MHz, well beyond the recommended 1MHz max switching frequency.  recommend to reduce the switching frequency to below 500kHz.
    • You may need to raise C13 to  100pF -1000pF to filter out the ringing on the sensed current signal.
    • Please use the Webench to help you design.

    Thanks,

    Youhao Xi, Applications Engineering

  • Dear,

    What if i provide 12V of the input in the DC Boost?

    R18 i will update to 154K based on the simulation results. So Do i need to change the value of C13 ?

    DC Boost WBDesign7_Load Transient-1.pdf

  • Hi Tirthal,

    The IC has internal leading edge blanking circuit which ideally would not require external filtering.  However, in may designs there is excessive ringing on the current sense signal extending beyond the leading edge blanking interval.  C13 is the component that  helps resolve this issue.  When you see large ringing during your test, raise C13 as recommended.

    Thanks,

    Youhao