• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 29 subscribers
  • Views 550 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

DRV8256: DRV8256,PWM, heat,

kevin.huang_FJXM
Expert 2925 points
Part Number: DRV8256

Drv8256, when using PWM speed regulation,

The slower the speed, the more serious the chip heating

Almost no heat at full output

What is the problem?

  • 0
    TI__Guru 55605 points

    Kevin,

    Can you tell me more about the load and the max current?  If they short out R18, similar results?  The voltage drop across that sense resistor should NOT exceed 200mV. 

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Expert 2925 points

    Hi Ryan：

    The load is a DC 20V brush motor, and the maximum current is about 0.8A. The result of short circuit R18 is the same. The average voltage of R18 is less than 200mV, and the starting moment of PWM cycle is more than 200mV

    The following is the duty cycle 90%, frequency setting 20kHz, R18 voltage waveform and output current

  • 0 in reply to kevin.huang_FJXM
    TI__Guru 55605 points

    Kevin,

    How many devices were tested?  Even peak voltages exceeding 200mV can damage the device.  Can you test a brand new device with R18 shorted and see if there are issues?

    It would also be good to get plots of the input (PH/EN) and outputs (OUT1/OUT2) to see if the device is behaving as expected.  

    Regards,

    Ryan