• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 29 subscribers
  • Views 97 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8889-Q1: About the problem of DRV8889 stepper motor chip

zhang lin
Prodigy 200 points
Part Number: DRV8889-Q1

Tool/software:

Hello expert,

I am using the motor chip DRV8889. The application scenario is the stepper motor of the car light. I have a few questions to confirm:

1. How to arrange the wiring harness when the chip is connected to the motor is beneficial to EMC. Do AOUT1 and AOUT2 wiring harnesses need to be twisted in pairs? Is it helpful to EMC if twisted in pairs.

2. What is the accuracy of the current obtained by The TRQ_DAC register set by the chip and the actual tested current? For example, the motor needs to have a holding current when it is not operating, there is a 10% error in my actual test current. Is this normal.

3. Is there any DRV8889 test program, we need some sample code to realize the acceleration and deceleration of the motor.

Thanks

  • 0
    TI__Mastermind 24865 points

    Hello Zhang,

    Thanks for contacting via this forum and thank you for using the DRV8889-Q1 stepper driver. This device is well suited for automobile headlight applications, especially its integrate stall detection feature, https://www.ti.com/lit/an/slvaei3/slvaei3.pdf.

    zhang lin said:
    1. How to arrange the wiring harness when the chip is connected to the motor is beneficial to EMC. Do AOUT1 and AOUT2 wiring harnesses need to be twisted in pairs? Is it helpful to EMC if twisted in pairs.

    Yes this would be a good approach for EMC. Also having four capacitors, one each on each output closer to the motor connector in the PCB would be helpful. Typical values would be 2.2 nF to 10 nF each capacitor on xOUTx to GND.

    zhang lin said:
    2. What is the accuracy of the current obtained by The TRQ_DAC register set by the chip and the actual tested current? For example, the motor needs to have a holding current when it is not operating, there is a 10% error in my actual test current. Is this normal.

    The current sense ITRIP accuracy depends on the current as a percentage of the 1.5 A full-scale current IFS. See below snippet from the datasheet. The TRQ_DAC is an additional numerical scalar on top of this IFS setting. 10 % error for integrated current sense and for hold current setting using TRQ_DAC scalar seems reasonable.

    zhang lin said:
    3. Is there any DRV8889 test program, we need some sample code to realize the acceleration and deceleration of the motor.

    The DRV8889-Q1EVM source code for the MCU on-board can be downloaded from https://dr-download.ti.com/software-development/support-software/MD-Uuebrq3CKB/01.00.00.0B/slvc796b.zip from the EVM webpage https://www.ti.com/tool/DRV8889-Q1EVM. This source code uses a linear acceleration and deceleration profile generator which is also explained in the attached.

    Stepper Motion Control.pdfMotion profile C source code.pdf2605.DRV8889Q1_Stall_Detect_Flowchart.pdf  

    Regards, Murugavel