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DRV8434A: How to use DRV8434 Driver IC to control stepper motors

wang sky
Prodigy 70 points
Part Number: DRV8434A
Other Parts Discussed in Thread: DRV8434, , DRV8434S

Tool/software:

I have 2 questions about utilizing the DRV8434 driver IC to control a stepper motor, the questions are as follows:

1. Using DRV8434 to drive a stepper motor, how can I make the stepper motor return to the home position first after power up without a sensor?

2.My motor is rotating up and down, why is it easier to generate a stall signal from STL_REP PIN when rotating up, but not to generate a STALL FAULT signal from STL_REP PIN when rotating down?

3.Is it possible to design the circuit without using TRQ_CNT/STL_TH? If I don't use this PIN, will it prevent me from detecting STALL and FAULT?

  • 0
    TI__Expert 6190 points

    Hi,

    Thanks a lot for the question.

    Please note that the device expert is current out of office. Please give them couple of days to respond.

    Thanks,

    Ibinu

  • 0 in reply to Ibinu Alaudeen Nadeera
    TI__Mastermind 28605 points

    Hi Wang,

    wang sky said:
    1. Using DRV8434 to drive a stepper motor, how can I make the stepper motor return to the home position first after power up without a sensor?

    The DRv8434A cannot do this by itself. The MCU controlling the DRV8434A should use the stall detection feature and detect end of travel and return to home position based on this end of travel position.

    wang sky said:
    2.My motor is rotating up and down, why is it easier to generate a stall signal from STL_REP PIN when rotating up, but not to generate a STALL FAULT signal from STL_REP PIN when rotating down?

    It looks like the friction force difference or may be travel against gravity vs. with gravity one direction vs. the other is causing this variation. This behavior is due to mechanical phenomenon.

    wang sky said:
    3.Is it possible to design the circuit without using TRQ_CNT/STL_TH? If I don't use this PIN, will it prevent me from detecting STALL and FAULT?

    For proper stall detection the DRV8434A requires a stall threshold to compare with it. When STL_MODE pin is Hi-Z the stall threshold can be internally set using a learning procedure described in the datasheet. With this operating mode the TRQ_CNT/STL_TH pin can be left unused. However, as per TI recommendation a 1 nF capacitor must be connected from this pin to GND regardless. Thank you.

    Regards, Murugavel  

  • 0 in reply to Murugavel4637
    Prodigy 70 points

    Regarding the 3rd question, is it possible to write parameter values to the DRV8434's register in torque count mode or stall threshold mode by using code in the DRV8434 without using the PIN TRQ_CNT/STL_TH by using the learning programme?

  • 0 in reply to wang sky
    TI__Mastermind 28605 points

    Hi Wang,

    The DRV8434S is the SPI version with registers. It also has a stall threshold learning feature or the stall threshold can be programmed directly to the stall threshold register. The DRV8434S does not have TRQ_CNT/STL_TH pin only the DRV8434A version (GPIO and analog control) has this pin. Thank you.

    Regards, Murugavel