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LM5157EVM-SEPIC: Input Voltage Range for 0.5A to 1A load

Part Number: LM5157EVM-SEPIC

Hi,
I have a question for input voltage range of LM5157EVM-SEPIC.  

It looks that the spec of input voltage range in electrical performance table requires 6V to 32V of input voltage for 1A load and 4V to 6V for 0.5A to 1A load.

I believe we can apply 32V to input voltage, "Vin" for 0.5V to 1A load and then the maximum limit of input voltage is not 6V.  Is my understanding correct?

Best Regards, Taki

  • Hello Taki,

    Thanks for reaching out to us via e2e.

    The limitation of the EVM with the chosen components is the other way round:
    The maximum current that the inductor can handle without derating is 2A.

    When you boost from 6V input to 12V@1A output you will draw about 2A on the input side which is right at the edge.

    If you wanted to boost from 4V input to 12V@1Aoutput you would draw about 3A on the input side which would be too high for the inductor.
    Therefore, if the input voltage is below 6V, this board can only provide about 0.5V of load current. (See section 1.2 in the datasheet / diagram below.)

    In your case when the input voltage is around 32V and does not drop below 6V, there is no limitation for the output current.
    Anything between 0A and 1A will work.

    Best regards,

    Harry

  • Hello Taki,

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

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

    Best regards,
    Harry