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Original question:

FDC2214: Current Drive Control Registers

FDC2214: INIT_DRIVE

Eugene Seubert
Prodigy 10 points
Part Number: FDC2214

Hello TI,

I'm working with the FDC2214 right now and trying to understand how the current driver works. Referencing this post: https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/852838/fdc2214-current-drive-control-registers I had the following questions:

  • Is there an updated datasheet for the FDC2214? The aforementioned post mentioned an error in the datasheet and going to fix it in the next revision.
  • What is the INIT_DRIVE current field? There doesn't seem to be any register with that field.
  • In full current drive mode, does the 2214 drive with the max current, then settle to the minimum current required to have a Vpk between 1.2V to 1.8V? If so, does that essentially automatically set the timing of the system?

Thanks!

Eugene

  • 0
    TI__Mastermind 40295 points

    Eugene,

    You can see the latest FDC2214 data sheet at https://www.ti.com/lit/gpn/fdc2214.

    It appears the error pointed out in the earlier thread is still there. The data sheet has been rev'd, but it is before the date of that E2E thread.

    I am guessing the INIT_DRIVE mentioned in the data sheet is some kind of strange typo, or may be a field in one of the reserved areas, and therefor can't be changed.

    The device ramps the current to try and achieve the desired amplitude and then settles over a predetermined interval (SETTLECOUNT).
    Figures 13 and 14 in the data sheet illustrate this.

    Regards,
    John

  • 0 in reply to John Miller - Sensing
    Prodigy 10 points

    Just to be clear, it does that in full current drive mode, correct? Low powered mode just uses the value in CURRENT_DRIVE?

    I see the FDC2214EVM GUI can poll the 2214 for the INIT_CURRENT but it always is NaN. Can I get clarification which part of the CURRENT_DRIVE register is the INIT_CURRENT?

    Thanks!

    Eugene Seubert

  • +1 in reply to Eugene Seubert
    TI__Mastermind 40295 points

    Eugene,

    There doesn't appear to be any info in our archives on the INIT_CURRENT field.
    As a guess, the data sheet entry is probably a mistake and the field doesn't exist, or - more likely -  it is in the 10-bit reserved field and can't be modified.

    Regards,
    John