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DRV2625EVM-CT: How to improve the vibration

Hirokazu Takahashi
Expert 8420 points
Part Number: DRV2625EVM-CT
Other Parts Discussed in Thread: DRV2625

Dear Support team,

I'm evaluating DRV2625EVM with the default setting at EVM start-up by connecting our LAR.
But, I'm feeling the vibration of DRV2625 weaker than other company products.
If you have any ideas to imporve it, please let me know.

Best Regards,
Hirokazu Takahashi

  • 0
    TI__Guru* 84915 points
    Takahashi-san,

    One way would be increasing the Rated Voltage in the Voltage Menu. The Rated Voltage is associated to the vibration strength. If it is increased, you should get better results. In addition, I suggest to apply an auto-calibration routine after changing the rated voltage.

    Best regards,
    Luis Fernando Rodríguez S.
  • 0 in reply to Luis Fernando Rodriguez S.
    TI__Expert 8420 points

    Hello Luis-san

    Thanks for reaching out.
    How can we decide Rated Voltage? Does it depend on LRA specification?

    Shoul we set Rated Voltage to less than Over Drive Voltage, shouldn't we?
    How we can decide Over Drive Voltage?

    Best Regards,
    Hirokazu Takahashi

  • 0 in reply to Hirokazu Takahashi
    TI__Guru* 84915 points
    Takahashi-san,

    The Overdrive voltage can be understood as the maximum peak voltage that is allowed regardless of the mode (open or closed mode).

    Usually, in closed-loop mode, the Rated Voltage is the diving voltage that the driver will output during steady state. Temporarily, it is possible to have a higher voltage determined by the overdrive voltage (usually, when the driver is just enabled). In open-loop, the rated voltage is ignored. Instead, the overdrive voltage is used to set the full-scale voltage.

    The rated voltage depends of the LRA specification. A recommended way to configure the overdrive peak is with the expression below:

    Voverdrive_peak >= Vrated_voltage _RMS x ( √2 )

    Please take a look at this document for more details about the device configuration.

    www.ti.com/.../getliterature.tsp

    Best regards,
    Luis Fernando Rodríguez S.
  • 0 in reply to Luis Fernando Rodriguez S.
    TI__Expert 8420 points

    Hello Luis-san

    Thanks for your support.
    If Voverdrive_peak > Vrated_voltage_RMS > Voverdrive_peak / √2, how problem will be occured?

    Best Regards,
    Hirokazu Takahashi

  • 0 in reply to Hirokazu Takahashi
    TI__Guru* 84915 points
    Takahashi-san,

    The problem could be associated to the heavy mass where the LRA load needs to be glued to get good results.

    Could you try the procedure below, please?

    1.- Fix your LRA on a solid mass (100g mass preferible). The LRA load requires to be glued of a heavy mass so the calibration procedure can be correctly made.
    2.- Start the auto-calibration procedure. The DRV2625 EVM will set the optimal parameters.
    3.- If the vibration is still weak, increase the Rated voltage and the Overdrive voltage.

    Have you tested this procedure? Do you have different results?

    Best regards,
    Luis Fernando Rodríguez S.