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DRV2605L: LRA/ERM actuator vs Piezo Haptic actuator

Ernest Yong
Expert 4315 points
Part Number: DRV2605L
Other Parts Discussed in Thread: DRV2667, DRV2604

Hello all,

I have a couple of question to ask regarding DRV2605L and DRV2667.

  1. What is the different between the LRA/ERM actuators (DRV2605L driver) versus the Piezo haptic actuators (DRV2667)?
  2. Can the DRV2605L driver drive the Piezo haptic actuators? If no, why?

Thank you for your time.

Best Regards,

Ernest Yong

  • +1
    TI__Mastermind 18935 points

    Hi Ernest,

    the main difference is that LRA/ERM actuators are lower voltage (3-5V) inductive loads, and Piezo actuators are higher voltage(30-100 V) capacitive loads 

    The DRV2667,2665,8662,2700 Piezo drivers are Class-AB amplifiers with high voltage (up to 105V peak) boost converters to supply the necessary high voltage for a piezo.

    The DRV2604,2605,2604L,2605L,2624,2625 LRA/ERM drivers are Class-D amplifiers that operate on a single low voltage supply(2.5-5.5V). these drivers have an auto resonance tracking algorithm that will track the velocity of LRA. this is important because to get the most vibration, and efficiency the LRA needs to be driven within a narrow bandwidth. typically a few Hz +/- the resonance

    The DRV2605L is not at all suited to drive a piezo, because the voltage is not high enough (you would feel no vibration) and since the DRV2605L is a Class-D amplifier the high frequency switching of the amplifier will have high peak currents into the capacitive load. this can damage the FETs inside the DRV2605L.

    Regards,

    Arthur

  • 0 in reply to Arthur Brown
    TI__Expert 4315 points

    Thank you for your detailed explanation. Really helpful.