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LM5176EVM-HP: Power management forum

Matthew Chen
Intellectual 1240 points
Part Number: LM5176EVM-HP

Hi  team,

i try to make the LM5176EVM to adjustable output from 8V to 48V. Below are the changes in SCH, the rest are remain the same.

Testing with no load, CCM, DITHER ENABLE, VIN = 28V, the board works well when the output changes from 8V to 25V. But when makes the output go higher than 25V, the current increase (up to 1A) and the device burned.

is it possible to modify the board adjustable output? is there anything i missed to change make the chip burned? Could you give some advice to modify the circuit to adjustable 8V-48V output?

Thanks a lot

Matthew

  • 0
    TI__Mastermind 49951 points

    HI Matthew,

    thank you for using the E2E forum.

    When you say the device is burned - which one do you mean.

    From the design the weakest parts are the Boost side MOSFETs as this are just 30V types and my assumption is that this get electrically overstressed.

    Beside that I recommend to still keep the some of the low size capacitors on the output side for the filtering of the high frequency signals.

    The Cap on BIAS is just rated for 50V -  this is too low for a good design considering temp, device variation and aging. A margin of > 40% is highly recommended.

    Best regards,

     Stefan 

  • 0 in reply to Stefan Schauer
    TI__Mastermind 49951 points

    Hi Matthew,

    I have not seen an update for the last 15 days, so I assume the questions are/or answered and the issue is solved.
    I close this thread now. If there is still something open reply and the thread will get open again.
    If you have any other question or of the thread gets locked, please open a new one.

    Clicking the Resolved Button also helps us to maintain this forum.

    Best regards,
    Stefan