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DRV8301 Power-up State w/o SPI running

Edward Averill
Genius 3100 points
Other Parts Discussed in Thread: DRV8301

I have a nice DRV8301 BOOST board here and I'm trying to chase down a problem.

Right now, I don't have the SPI running on my prototype board.  I'm seeing the PWMs running but there's no voltage out from the board, and none of the fault lines are active.

I have EN_GATE hooked to the 3.3V giving it s solid HIGH.

I'm assuming that, by default, when the chip powers up I can just feed it with the PWMs and I should see something come out, right?

All help appreciated.

Ed Averill

  • 0
    TI__Mastermind 21320 points

    Hi Ed,

    What PWMs are you feeding to the DRV8301? By default it is in 6-PWM mode and requires the complementary signal.

    Do you see a FAULT reporting from the device?

    Are you using the BoosterPack standalone? How you do have it configured? 

  • 0 in reply to Nicholas Oborny
    Genius 3100 points

    My setup is an MSP430 driving the PWMs and reading the Hall sensors on a Moog motor. I'm driving 6 PWMs into the BOOST board, which is wired up to a 24V power supply.

    I don't see the FAULT light on and probing the board with a scope doesn't show any of the FAULT/OCTW lines active (both are HIGH).

    I'm going to try to get my hardware guy to help me out here, it seems that things should be working..

    Thanks for the response!

    Ed Averill

  • 0 in reply to Edward Averill
    Genius 3100 points

    I replaced the motor and have checked the PWM inputs to the DRV BOOST board. 

    I'm running the MSP43o closed-loop-control example code, what I see from the PWMs on my scope matches what I expect, but the output from the DRV is at a VERY low level (less than 3V).. and the voltage is the same across all 3 motor outputs.

    I'm assuming at this point that I've somehow fried the chip, and will be ordering a second BOOST board.

    Does anyone have any other suggestions than "replace it"?

    Ed Averill

  • 0 in reply to Edward Averill
    TI__Mastermind 21320 points

    Hi Ed,

    There are a few checks to see if the chip is damaged or we still have a setup issue.

    With EN_GATE = HIGH and power applied please measure the voltage of the GVDD, AVDD, and DVDD regulators.

    You can measure across the bypass capacitor for each one. Refer to the schematic for the capacitor names.

    Can you also provide a scope capture of the PWM inputs (INL_A, INH_A) and output (MOT_A) for one of the half-bridges

  • 0 in reply to Nicholas Oborny
    Genius 3100 points

    I'll give it a shot.. will likely be tomorrow before I have it all.

    I did disconnect the 3 motor control outputs and now when I fire up the PWMs on the MSP430, I'm not seeing the FAULT light or the nFAULT pin going LOW.. very strange.

    Sorry for all the newbie questions, this is my first motor control project..

    *update* Turns out the documentation for the motor I got was wrong, so I had the B and C outputs swapped.. fixing that has removed the FAULT light, But no outputs whatsoever from any of the 3 motor control connectors, so I'm fairly sure I cooked something.  I have two BOOST boards coming tomorrow and Monday now.

  • 0 in reply to Edward Averill
    TI__Mastermind 21320 points

    No worries. I would still go ahead and check those voltages.

    We are happy to help.

  • 0 in reply to Nicholas Oborny
    Genius 3100 points
    Sorry I didn't get back to you, I got real sick and was out.

    I got SOMETHING happening, the motor buzzes a bit before I see a FAULT condition now. I'm having issues unrelated to the DRV chip, the Hall sensors on this Moog motor don't seem to be working properly.. ugh.

    Thanks for all the assistance, have a great holiday!

    Ed Averill
  • 0 in reply to Edward Averill
    TI__Mastermind 21320 points
    No worries. Have a good holidays. Some advice I can give is to break things down into smaller systems. Ensure the MCU is functional, driver is functional, halls are reporting correctly, etc. All before even hooking the motor up. Motor systems are not trivial although we do are best to ease the development pain.