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LM5175: DC/DC 2V to 30V Adjustable Power Supply

alikaan
Expert 2315 points
Part Number: LM5175

Hi there,

I'm designing power supply but I need a advise for main IC. 

Vin could be 24V

Vout is 2V to 30V and current is 1A

Output should be adjustable, I can adjust with potentiometer, I found LM5175 but Webench tool does not support it. 

Thanks, Ali.

  • 0
    TI__Mastermind 21720 points

    Hi Ali,

    Thanks for reaching out to TI with your questions.

    The LM5175 can be setup to operate as a variable output voltage supply. WEBENCH doesn't support this due to most designs requiring a constant output voltage while having a varying input voltage. This can be done with a pot as you suggest. The quickstart calculator should help with component selection.

    Thanks,

    Garrett

  • 0 in reply to Garrett Roecker
    Expert 2315 points

    Hi Garret,

    Thank you for your reply. I designed 2 difference schematic with LM5175. My question is when I change the feedback resistor value, Rcomp and Ccomp and inductor values are also changing. I attached the screenshoots.

    This one Vin= 24 Vout=2V @ 1A

    This one is Vin = 24V Vout = 30V @ 1A

    I would like to use just potentiometer for adjusting the voltage. I need a help for fixing this values.

    Thanks, Ali.

  • 0 in reply to alikaan
    TI__Mastermind 21720 points
    Hi Ali,

    You should set the compensation around the worst case conditions. This is going to be the maximum boost condition, which appears to be VIN =24V -> VOUT=30V@1A. Calculate the compensation values (RCOMP, CCOMP, CHF, Top RFB) and then use these for all the other conditions. Simply change the bottom feedback resistor to modify the output voltage.

    -Garrett