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LM5170-Q1: Current sense with Hall sensor

Michael Daimer
Intellectual 1725 points
Part Number: LM5170-Q1
Other Parts Discussed in Thread: LM5170

Tool/software:

Hi Team,

I have question on LM5170-Q1. Is it possible to use a Hall based current sensor to sense the current and feed this information into the device?

Do you have experience with such an use case and what are some traps, you might fall into as designer of such an circuit.

Thanks and best regards,

Michael

  • 0
    TI__Mastermind 22540 points

    Hi Michael,

    LM5170 current sense amplifiers have around 100uA offset current @12V.

    For high accuracy, make sure the external current sense amplifier output has a low output impedance.

    And please also make sure the delay is acceptable.

    Best Regards,

    Feng

  • 0 in reply to Feng Ji
    TI__Intellectual 1725 points

    Hello Feng,

    thanks for your answer. Do you have an app note on such a use case? 

    Would you use the current sense amplifier as buffer between Hall sensor output and LM5170 sense input?

    Can you recommend a hall sensor, which would fit?

    What would be an acceptable delay from your point of view?

    Thanks,

    Michael

  • 0 in reply to Michael Daimer
    TI__Mastermind 22540 points

    Hi Michael,

    We don't have such app note.

    I think we will need an amplifier between Hall sensor output and LM5170 sense input due to the offset current.

    Can you tell me the information of your application? Why do you need a hall sensor?

    You may meet issue of zero current detection (LO signals) if you have excessive delay. I think the delay should be much lower than one switching cycle.

    Best Regards,

    Feng