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DRV8308 and Hall sensors placement

Other Parts Discussed in Thread: DRV8308EVM, TIDA-00197, DRV5013, DRV8308


I have DRV8308 predriver, DRV5013 Hall sensors and old FDD BLDC motor with 15 windings EDIT: and 20 pole pairs. I would like to design PCB for this motor like in TIDA-00197 (the future version also with FG track on PCB). I also have DRV8308EVM and I will probably start with simple PCB with motor and Hall sensors mounted, that I could connect it to EVM board, like attached TelcoMotion DT4260-24-055-04H-TI.

In TIDA PCB design Hall sensors are placed with 45 deg mechanical distance. In TelcoMotion motor I can't see. In PCB of my old motor Hall sensors are placed with 120 deg distance.

1) How Hall sensors placement depends on predriver type?

2) How Hall sensors placement depends on motor type? I suppose it is related to number of magnetic poles EDIT: (unfortunatelly now I don't know it, I only see 15 windings).

  • Daniel, for a 3-phase BLDC, the Hall sensor spacing should equal 2 / #poles *120 degrees.  For your case, 2/20*120 = 12°.

    So your Halls could be at:
    Hall1:  0°
    Hall2:  12°
    Hall3:  24°

    You can also add 3*12° to any of those numbers, and still have 120° phase separation between the Halls.  For example:
    Hall1:  0°
    Hall2:  48°
    Hall3:  24°

    Determining where 0° must sit is more involved.  If you measure your TelcoMotion motor you might be able to figure that part out.

    Best regards,