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BQ77PL900: speed of current measurement

Clemens Hafner
Prodigy 50 points
Part Number: BQ77PL900

How fast is the current measurement by the bq77pl900? Meaning how wide (or long regarding its duration) does a peaking current have to be in order for the bq77pl900 to detect a short-circuit or overcurrent condition? We are building an application with a motor controller where narrow current peaks occur and we want the bq to react accordingly.

I did not find any information on the detection time (only the adjustable delay) in the datasheet.

Thank you very much.

Regards
Clemens Hafner

  • 0
    TI__Guru 54715 points
    Hi Clemens,
    The part has sampled comparators, the clock is 32kHz (31 us). The circuit will have a exponential response due to filtering from circuit components or parasitics. Like any comparator it will respond faster to a larger overdrive, but there is no data on this. If a 0 us delay is selected and a narrow pulse arrives over the threshold between samples it could be missed, but with a different arrival time it may be detected. Use appropriate filtering and delay selection for your design.
  • 0 in reply to WM5295
    Prodigy 50 points

    Ok, thank you very much.

    Regards
    Clemens