• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 29 subscribers
  • Views 1238 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.

DRV8353: DRV8353 - Damaged after freerun when stop PWM

Peter Mirtschink
Prodigy 220 points
Part Number: DRV8353

Dear all,

I test with an DRV8353 Evaluation Kit an an BLDC in freerun at 18V and approx. 6A nominal current in free run. The free run ist good. But if I stop the PWM Signal to the DRV8353 the Motor stop rotating immediately. After two or three times the DRV8353 is damaged. If I start PWM signal the fault LED is on and the motor don't start moving. It is a bad solution to stop PWM immediately?

I hope you understand. If you need more information I try to give it to you!


Thank you!

  • 0
    TI__Guru 63710 points
    Peter,

    Could you show me a scope image of the Switching node when you shut off the PWM? Is there a voltage spike or similar?

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 220 points

    Hi Adam,

    sorry I can't, because the IC is damaged. It is possible, when I turn off the PWM then all MOSFET are "closed". But in the motor is some rest voltage. Can this voltage flow back to GND over the IC and this damage the IC? It is recommended use brake before stop PWM that the energy can flow back to GND?

    Regards,

    Peter

  • 0 in reply to Peter Mirtschink
    TI__Guru 63710 points
    Peter,

    Which input mode are you using? 1x, 3x, 6x mode?

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 220 points

    Dear Adam,

    I use 1x Mode and PWM with 1 kHz or 20 kHz. I have two boards and booth are damaged with the same problem.

    Regards,

    Peter

  • 0 in reply to Peter Mirtschink
    TI__Guru 63710 points
    Peter,

    It is not a great practice to stop the PWM without slowing it first or using the Brake feature of the device. The problem is that the rotating energy has no place to go and therefore the IC gets damaged. If you use the brake feature, the Lowside FETs will still need to circulate the energy stored in the rotating motor and mass. For this reason you should monitor the switch node voltage when using the brake to make sure the device spec is not violated.

    The best action would be to slow the PWM so that the motor can come to stop more gradually. Even a few mS of slow down is better than a sudden stop.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 220 points

    Adam,

    thank you very much. I will try to slow down PWM and use Brake in last steps only to be sure that there is no high voltage.

    Regards,

    Peter