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DRV8353RS-EVM: Erratic Behaviour

Mario Marques
Prodigy 10 points
Part Number: DRV8353RS-EVM
Other Parts Discussed in Thread: DRV8353

Hello,

I am driving a 48V BLDC motor with 32V using the example code from the Instaspin Lab 5b, on Code Composer studio. I am bypassing motor identification.

When I increase the speed of the motor the fault LED on the DRV8353 board turns on. However, when I stop the motor, the fault LED turns off. It is a GDF fault. I tried changing the IDRIVE and the time settings like the datasheet indicates to no avail.

I measured the low and high side Mosfet signals. The GHB (Yellow) signal has erratic behavior, not following the INHB (purple) signal, as can be seen in the picture below. The other Mosfet signals are fine. Could you try and help me troubleshoot this issue?

 

  • 0
    TI__Mastermind 18981 points

    Hi Mario,

    Thanks for posting your question to the e2e forum - 

    We are looking into this further and will follow up with some more information. 

    Thanks and Best Regards,
    Andrew 

  • 0
    TI__Mastermind 18981 points

    Hi Mario,

    Thanks for your patience - please see feedback and questions below: 

    1. for the IDRIVE and tDRIVE settings you used, may I have some clarification as to which specific settings you have tried & haven't yet tried?
      1. if there is ringing on the MOSFET gates, it may be a drive current/time setting like you suggested
      2. however, this is a carefully tuned process based on the MOSFET's Qgd spec, as well as your intended rise time.
    2. It is strange, however, that only one MOSFET phase (B) would have this behavior.
      1. I also advise that you help check the B-phase MOSFETs for damage by doing a resistance measurement between gate and source terminals, drain and source, etc..  
      2. is this a new EVM? 
    3. Lastly, is there a specific speed in which the gate-drive fault occurs at? 
      1. I see ~15kHz in the purple waveform, but am curious about how bad the gate drive waveform for phase B might be at 10kHz, 5kHZ, etc..

    Resources to investigate:

    Thanks and Best Regards,
    Andrew

  • 0
    TI__Mastermind 18981 points

    Hi Mario,

    Just following on this thread to see if there has been any update on this problem - 

    I posed a few questions in my latest response to see if we can better understand & define the issue so some more precise solutions can be suggested. 

    Please let me know your thoughts on these, and if you have any additional data or questions for us 

    Thanks and Best Regards,
    Andrew

  • 0 in reply to Andrew Liu
    TI__Mastermind 26046 points

    Hi Mario,

    Do you need any additional help?

    Thanks,
    Aaron

  • 0
    TI__Mastermind 18981 points

    Hi Mario, 

    Do you need any additional help with this debug? 
    Please let us know if the earlier debug steps and information have resolved the issue already 

    Best Regards,
    Andrew

  • 0
    TI__Mastermind 18981 points

    Hi Mario, 

    Closing this thread for now - please send us a message or click '+ask a related question' if you would like additional assistance on this. 

    Thanks and Best Regards,
    Andrew