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DRV8881: DRV8881E and DRV8881P - Key differences

sivasuryan.R
Intellectual 610 points
Part Number: DRV8881

Hi

  The main difference between the DRV8881E and DRV8881P are

1. DRV8881E has auto-tune feature for stepper motors

2. DRV8881P has Para (parallel) feature to increase current capacity for Brushed DC motors (additional to stepper motors).

3. DRV8881P has brake option (low side slow decay) control inputs


Can I drive stepper motor using DRV8881P with external DAC for controlling coil current as like in DRV8881E except auto tune? as I need Brake option in stepper motor control

Is there any other differences kindly note me.


Thanks and regards,

R.Sivasuryan

  • 0
    TI__Guru** 114905 points
    Hi R.Sivasuryan,

    Yes you can drive a stepper motor with the DRV8881P and external DAC.

    Overcurrent protection is different between the DRV8881E and DRV8881P. See section 7.3.12.3 for details.
  • 0 in reply to Rick Duncan
    Intellectual 610 points

    Hi Rick,

      Thanks. While I using the external DAC for AVREF and BVREF in DRV8881P can the current regulation (Once the current hits the current chopping threshold, the bridge enters a decay mode for a fixed period of time to decrease the current, which is configurable between 10 and 30 μs through the tri-level input TOFF) done by the DRV8881P driver IC itself (like in DRV8881E) or I need to have external current sensor and comparator to do the current regulation externally.

    I think both DRV8881E and DRV8881P are pin to pin compatible, if using DRV8881P then I need to add Current sensor and comparator circuits externally ?

    Thanks in advance

    R.Sivasuryan

  • 0 in reply to sivasuryan.R
    TI__Guru** 114905 points
    Hi R.Sivasuryan,

    Current regulation is operational in the DRV8881P. It is controlled by the A/BVREF voltage, TRQ pins, and sense resistor value as described in Equation (1).

    The DRV8881E and DRV8881P are pin to pin compatible. The control interface (Tables 1 and 2) is different. The DRV8881P does not need external current sensor and comparator circuits for typical operation.

    You should only need external circuitry if you are attempting to operate the device outside the pre-defined abilities. Examples are monitoring the current in slow decay or changing the toff time to 15us. The DRV8881P (and DRV8881E) does not monitor the current during slow decay. Changing toff to 15us would require disabling the internal current regulation, monitoring the current externally, and controlling the decay mode via the inputs.