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DRV8850: Could DRV8850 run from a 6.0V supply? The Abs max is 7.0V . Recommended is 5.5V .

Nick Alexeev
Intellectual 645 points
Part Number: DRV8850
Other Parts Discussed in Thread: DRV8411A

Colleagues,

I’m considering DRV8850 for a new design which will be powered with 4x alkaline cells in series. It would be convenient if I could run the DRV8850 from 6.0V . The Abs max is 7.0V . Recommended is 5.5V . The motor current will be 0.2A continuous, 1.5A peak.

Does it make sense to push beyond 5.5V ? What might be the damage? Voltage overstress? Thermal? Can it be addressed with derating other parameters?

I’ve used DRV8850 successfully in the past. I keep coming back to it, because it’s a simple-minded power stage with a current sensor. Advanced motor control PWM, comparator for current limiting will be in the microcontroller.

Best regards,
- Nick

  • 0
    TI__Guru 55605 points

    Nick,

    I am glad you had success with the DRV8850 and the simplicity of it and current feedback makes sense.  

    I think I have a part for you that will give you what you need in terms of simplicity and current feedback and easily support the 6V as well as low end of the battery range.

    https://www.ti.com/lit/ds/symlink/drv8411a.pdf

    The outputs can be paralleled to achieve a lower Rdson closer to the DRV8850. 0.2A continuous would be absolutely no problem.  Peak also not a problem.  Package size is even smaller at 3x3mm.

    Please let me know if the DRV8411A misses the mark in another way.

    Regards,

    Ryan

  • 0 in reply to Ryan Kehr
    Intellectual 645 points

    Hi Ryan,

    I'm going to neutralize the comparator in the DRV8411A, and use the comparator in the microcontroller.  I'm going to tie the VREF pin on the DRV8411A to +3.3V, and use a lower threshold voltage in the microcontroller.  Then the comparator in the DRV8411A will never trigger, because the comparator in the microcontroller will always trigger sooner.

    - Nick

  • 0 in reply to Nick Alexeev
    TI__Guru 55605 points

    Nick,

    That will work!  

    Regards,

    Ryan