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DRV8711: DRV8711 Driver issue

Srikanth Ala
Prodigy 30 points
Part Number: DRV8711
Other Parts Discussed in Thread: CSD18531Q5A

Hi,

We have designed a Board with DRV8711 used for Bipolar stepper motor driver.

But the board suddenly stops working and it generated APDF error and as per the suggestion, I changed the Lower side MOSFET gate resistance value to 100 Ohms.

Then it is generating another error called "BOCP".

And, We find the same behavior on the eval board also.

Please help us to solve this issue.

Regards,

Srikanth Ala

  • 0
    TI__Guru 56650 points

    Srikanth,

    1. "TI also recommends setting the dead time to 850 ns when adding a series resistor."

    Do you change the dead time to 850ns?

    2. in datasheet 7.3.8 Configuring Predrivers: If IDRIVE and TDRIVE are chosen to be too low for a given FET, then the FET may not turn on completely. TI suggests adjusting these values insystem with the required external FETs and stepper motor to determine the best possible setting for any application.

    What is IDRIVE and TDRIVE value in your test? Can we increase them?

  • 0 in reply to Wang5577
    Prodigy 30 points

    Dear Wang,

    We are using "CSD18531Q5A" MOSFET, and the dead time is 850ns.

    And, Driver register Configuration.

    // DRIVE register
    st_gDriveReg.u8_mAddress = 0x06;
    st_gDriveReg.u8_mIDRIVEP = 0x00;
    st_gDriveReg.u8_mIDRIVEN = 0x00;
    st_gDriveReg.u8_mTDRIVEP = 0x01;
    st_gDriveReg.u8_mTDRIVEN = 0x01;
    st_gDriveReg.u8_mOCPDEG = 0x01;
    st_gDriveReg.u8_mOCPTH = 0x01;

    Please let me know what values should I change.

    Thanks for your support.

    Regards,

    Srikanth Ala

  • 0 in reply to Srikanth Ala
    TI__Guru 56650 points

    Srikanth,

    Would you increase the IDRIVE and TDRIVE value to see if the APDF or BOCP is still there?

  • 0 in reply to Wang5577
    Prodigy 30 points

    Dear Wang,

    We are using CSD18531Q5A MOSFETS.
    And, we are using a 24V supply and a stepper motor with 1.8A per channel.
    The following are the register configuration of the DRV8711.
    // Set default register settings
    // CTRL register
    DTIME   = 0x03;
    ISGAIN  = 0x00;
    EXSTALL = 0x00;
    MODE    = 0x04;
    RSTEP   = 0x00;
    RDIR    = 0x00;
    ENBL    = 0x01;
     // TORQUE register
    SIMPLTH = 0x00;
    TORQUE  = 0xFF;
     // OFF register
    PWMMODE = 0x00;
    TOFF    = 0x30;
     // BLANK register
    ABT     = 0x01;
    TBLANK  = 0x08;
     // DECAY register.
    DECMOD  = 0x03;
    TDECAY = 0x10;
    // STALL register
    VDIV    = 0x03;
    SDCNT   = 0x03;
    SDTHR   = 0x40;
    // DRIVE register
    IDRIVEP = 0x00;
    IDRIVEN = 0x00;
    TDRIVEP = 0x02;
    TDRIVEN = 0x02;
    OCPDEG  = 0x01;
    OCPTH   = 0x01;
    // STATUS register
    STDLAT  = 0x00;
    STD     = 0x00;
    UVLO    = 0x00;
    BPDF    = 0x00;
    APDF    = 0x00;
    BOCP    = 0x00;
    AOCP    = 0x00;
    OTS     = 0x00;

    When I do this configuration, my power supply got burnt.

    I request you to suggest the configuration of the register values.

    Regards,

    Srikanth Ala

  • 0 in reply to Srikanth Ala
    TI__Guru 56650 points

    Srikanth,

    Please order an EVM to check your setting. My lab time is limited. So, it would take a little bit long time to have a result.

    "my power supply got burnt." What power supply do you use (voltage and current rating)? Did you have any waveform? When you run the motor, on which step did the power supply get burnt?

  • 0 in reply to Wang5577
    TI__Guru 56650 points

    Hello, Srikanth,

    Datasheet "8.2.2 Detailed Design Procedure" includes the "8.2.2.3 Support External FETs" which gives IDRIVE, TDRIVE and TBLANK recommendation. Please calculate those parameters for your solution.