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DRV8214: SCL internal pull-down

Darren Jenkins
Genius 11466 points
Part Number: DRV8214

Tool/software:

Motor driver team,

On the DRV8214, the internal pull-down on SCL is leading to about 10uA of current draw for one customer's low power project.  Is there a way to disable this pull down while idle, or avoid this current draw in some other way?

From page 12 of the datasheet:

Thanks,

Darren

  • 0
    TI__Expert 6770 points

    Hi Darren,

    Thanks for the question.

    My device expert will look into the question and get back to you.

    Thanks,

    Ibinu

  • 0
    TI__Genius 13610 points

    Hi Darren,

    Unfortunately, there is no way to disable the internal pulldown resistor on the SCL pin.

    When are you seeing this 10uA of current draw, during sleep state, high logic, low logic, etc.?

    How are you measuring the current?

    What's the value of the eternal pullup resistor on SCL?

    Best,

    David

  • 0 in reply to David Medis
    TI__Genius 11466 points

    Hi David,

    The pull-up resistor they have is 8.2kOhm.  The current is being measured in Sleep state.  Is there any way to meet the datasheet sleep current numbers while having the I2C connected?

    Thanks,

    Darren

  • 0 in reply to Darren Jenkins
    TI__Genius 13610 points

    Hi Darren,

    There are two sleep current specs in the datasheet, IVMQ and IVCCQ. The internal logic is powered from VCC and so while the device is in sleep mode, IVCCQ will be the digital logic power delivered to the internal logic while in this state. The test conditions to meet this spec are generally given with no inputs or external loads (pull-ups included). 

    The external pull-up resistor is causing any leakage current to be drawn from this pin while in this state. 

    Is there a design limitation for how much current they can draw from the SCL pin or are they just trying to maximize power consumption?

    Best,

    David

  • 0 in reply to David Medis
    TI__Genius 11466 points

    Hi David,

    They're trying to minimize power consumption.

    Darren

  • 0 in reply to Darren Jenkins
    TI__Genius 13610 points

    Hi Darren,

    Understood. To reduce overall current consumption while the device is in the sleep state would be to reduce the motor voltage (if possible) and make inputs = 0V. I'm not sure how much of an affect this will have on the SCL leakage current but it is worth a shot if the customer is not doing this already. 

    Best,

    David