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DRV8834: Controlling trip current with xVREF under indexer mode

Kazuki Itoh
Genius 9445 points
Part Number: DRV8834

Hi team,

When driving stepping motor with DRV8834 in indexer mode, is it supported to control Ifs with xVREF?
My customer wants to use it to actively control the trip current depending on motor's driving or stopping state.
However, as the reference voltage scaling by internal DAC is listed in table 4, but I'm not sure if it support what my customer wants to do.

Also, if TI has any other motor driver recommendation for the requirement below, please let me know.

Stepper motor requirement:
Inductor resistance : 40Ω +/- 10%
Step count: 64 micro step
Max speed : 1320pps (1-2 phase excitation)
Max input voltage : 5.5V
Rated voltage : 4.6V
Minimum voltage : 4.0V

Best regards,
Kazuki Itoh

  • +1
    TI__Expert 8860 points

    Hi Kazuki-san,

    Yes, in order to use the microstepping control in indexer mode, the STEP pin will adjust the current regulation level of the micro-step. On each rising edge of the STEP input, the indexer will move to the next state in the table 4. 

    The full-scale current is then regulated by the RISENSE and VREF.

    The DRV8834 is only up to 1/32-step and it appears your customer would need at least 1/64-step.

    TI offers a wide range of solutions for 1/256-microstepping. Most of these solutions meet have a minimum voltage of 4.5 V and can be found in the following link.

    https://www.ti.com/motor-drivers/stepper-driver/products.html#2894=256& 

    Best,

    David