• State TI Thinks Resolved
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 31 subscribers
  • Views 90 views
  • Users 0 members are here
Support feedback
Options
Options
Related

DRV8323: application questions

Terry Hu
Expert 4500 points

Part Number: DRV8323

Hi Team,

Could you please help to check the questions from customer as below? Thanks.

  1. When VREF is powered by 3.3V & no VM, enable is pulled to high, will DRV8323 turn on some pins? Is any leakage concern for this condition?
  2. When VREF is powered by 3.3V & no VM, enable is pulled to low, will DRV8323 turn on some pins internally? Is any leakage concern for this condition?
  3. When enable keeps low, is there power sequence requirement of VREF & VM ? Is yes, which one should power on first?
  4. Our application has an accident condition that is :  VREF & VM & enable are on at the same time , INHA & INLB are pulled to high by controller, CAL (DRV8323 input pin) is also pulled to high accidentally by external circuit,  we didn’t see damage on DRV8323, but this condition caused damage of peripheral circuit. Do you have any idea of the damage path? 
  5. To mitigate the condition4, we would like to modify design to :  VREF & enable on, VM is off, CAL will not be pulled high, but INHA & INLB will be high at this time because of the limitation of controller, any concern of this condition? Especially the risk caused by IO out of control under this condition.

Best regards,

Terry

  • 0
    TI__Expert 4500 points

    Hi Team,

    Can anyone help to look at this? Thanks.

    Terry

  • 0 in reply to Terry Hu
    TI__Genius 9885 points

    Hi Terry,

    1. With no VM, device will not be powered, no pins will be driven. With enable high there may be some tiny amount of leakage (few uA) due to internal pull down resistor for ENABLE pin. We expect this to be negligible in the application

    2. With no VM, device will not be powered so no pins will be turned on. There is not a leakage concern for this condition.

    3. There is no power sequence required for the VREF and VM supplies.

    4. Is the application a motor? If you have INHA and INLB high, there will be a path from High side A mosfet through the load/motor, through the GND of lowside B. This will not damage the driver and is a typical use case during regular operations. Can you provide more information on the damage that occurred?

    5. If VM is off, there will be no response to any inputs.

    Thanks,

    Joseph

  • 0 in reply to Joseph Ferri
    TI__Expert 4500 points

    Hi Joseph,

    Regarding 3xPWM mode and 6xPWM mode, do they both support auto dead time insertion?

    Best regards,

    Terry

  • 0 in reply to Terry Hu
    TI__Genius 9885 points

    Hi Terry,

    Yes, both 3x and 6x PWM mode support device dead time insertion.

    Independent mode will be the only mode that will not insert dead time.

    Thanks,

    Joseph