• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 30 subscribers
  • Views 581 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.

Original question:

DRV11873: DRV11873

DRV11873: DRV11873

user5289545
Prodigy 50 points
Part Number: DRV11873

Hi Team,

we use DRV11873 to drive the permanent magnet dc micromotor, and we add the function of wireless charging in the middle of the motor, as shown in the figure below.

1: the fault phenomenon is that the dc motor cannot work normally when the power is supplied, and there is no voltage in U/V/W, so the test waveform is shown in the figure below.

If we remove the wireless charging function, the motor will work normally. How can the magnetic field affect the normal work of DRV11873? Thank you!

  • 0
    TI__Expert 6065 points
    1) I'm not as familiar with how the wireless charging can affect the DRV11873, but I can ask my teammates to see if they know. Meanwhile, some quick suggestions are below:
    a) Make sure PWMIN signal is still clean
    b) Don't leave FR pin floating, as maybe the RF from the wireless charging couples onto the pin
    c) See if RD pin goes from low to high, indicating a fault happened
    2) Can you explain exactly what happens when the motor doesnt "work normally"? For example, does the drv11873 try to start up the motor by outputting voltage on the phases, but the motor doesn't spin? Or does the motor spin a little bit, but then a fault happens?
  • 0 in reply to Sanmesh Udhayakumar
    TI__Expert 6065 points
    We're not sure how wireless charging can affect the DRV11873. We may be able to help a little more when you answer the questions above.
  • 0 in reply to Sanmesh Udhayakumar
    Prodigy 50 points

    1:

    A) PWMIN has always existed.

    B) the failure phenomenon of pulling up to 5V on FG and RD remains the same.

    C) the RD did change from low to high. Indeed, the chip detected a fault and started the drive again after 5 seconds.

    2:

    After the PWM signal was input, the chip tried to drive the motor and applied voltage, but the motor did not move.

    In the case of no interference from the transmitting coil of wireless power supply, the chip ignored PWM signal at startup and was driven by dc, and 10 phase changes were measured. PWM signal at the 11th phase change was intervened.

    When there is a wireless transmitter coil interference, chip attempts to drive motor, can be seen when the third phase PWM signal, the signal frequency is about 60 k, our wireless power supply is also on this frequency, should be a motor coil induction power supply for wireless transmitter coil magnetic field, the chip to drive the motor when the two parties work produced interference at the same time.Tank you!

  • 0 in reply to user5289545
    TI__Expert 6065 points
    1)I think it woud be useful to see where the wireless charging circuit is in relation to the motor and DRV11873. Can you send a schematic?
    2) When you say "In the case of no interference from the transmitting coil of wireless power supply, the chip ignored PWM signal at startup and was driven by dc, and 10 phase changes were measured. PWM signal at the 11th phase change was intervened.", does this mean that the motor didnt spin properly when the 11th phase change was intervened?
    3) I dont understand this: "When there is a wireless transmitter coil interference, chip attempts to drive motor, can be seen when the third phase PWM signal, the signal frequency is about 60 k, our wireless power supply is also on this frequency, should be a motor coil induction power supply for wireless transmitter coil magnetic field, the chip to drive the motor when the two parties work produced interference at the same time.Tank you!". Can you please explain a little more in full sentences?
    4) When I say "Make sure PWMIN signal is still clean", I mean make sure there isnt any noise on it.
    5) Please make sure Vcc doesnt have any noise on it as well.
  • 0 in reply to Sanmesh Udhayakumar
    TI__Expert 6065 points
    Because I havent received a response for over a week, I will close this for now. If you found your fix, I would encourage you to please post it so that others can benefit from viewing it. If you have any further questions, please respond to this thread.