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DRV8870: Unregulated Voltage

seogje cho
Prodigy 100 points
Part Number: DRV8870

Hello!

I am a newbie at DRV8870 Motor Driver.

I am going to connect unregulated dc24v to the VM pin of DRV8870 like as below schematic.

Would you please let me know whether there is some problem or not?

Your response would be highly appreciated.

Thanks,

  • +1
    TI__Expert 4955 points

    Hello Seogje Cho,

    I would be happy to help! As far as the power supply goes, 4.167 Vout ripple is entirely too much. We ideally want to see a ripple of less than 100mV. There are a couple of different ways in which you can solve this problem. You could use capacitors in parallel to have a larger capacitance, or you could look into implementing a pi filter in order to minimize the ripple. 

    There are a lot of sim tools out there that will allow you to test out different capacitors sizes and schematic configurations until you have a wave rectifier that you are comfortable with. WEBENCH is a pretty good one:

    www.ti.com/.../webench-power-designer.html

    Please let me know if you have any other questions.

    Best,

    Pedro Arango Ramirez.

  • 0 in reply to Pedro Arango Ramirez
    Prodigy 100 points

    Hello Pedro Arango Ramirez,

    Thanks, Your comment is very helpful.

    Best & Regards,

    Seogje Cho,