• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 30 subscribers
  • Views 45 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

DRV8212: Reverse Rotation Failure on MOTOR Output

Conor
Guru 11405 points
Part Number: DRV8212
Other Parts Discussed in Thread: STRIKE

Tool/software:

Hi,

■ Phenomenon

  • MOTOR1 (normal unit): Forward and reverse rotation work correctly.

  • MOTOR2 (faulty unit): Forward rotation works, but reverse rotation does not occur.

■ Observations

  • We have detected waveform discrepancies between the MOTOR2 output (Pin2 of the MCU) and the motor driver input.

  • The CPU appears to output a High signal on Pin2 after a set unlocking time following forward rotation, but the motor driver does not respond.

  • In contrast, a normal unit exhibits the expected waveform and successful reverse rotation.

  • I am having trouble with an application using DRV8212. It is highly likely that the IC is broken, so I would appreciate any comments on the cause of the failure.

  • As a result of ABA swapping, it was found that this phenomenon depends on a specific DRV8212.

  • When I checked the resistance between each terminal of the motor driver and Pin 4 (GND), I found that Pin 2 of the defective product and Pin 2 and Pin 3 of the normal motor driver were about 5MΩ, while Pin 3 of the defective product had dropped to about 300kΩ.

■ Question
Considering that Pin2 goes High but the driver does not activate, we suspect GPIO configuration issues, weak drive capability, or possible pin damage. Are there any known failure modes of this nature?

Thanks,

Conor

  • 0
    TI__Mastermind 23361 points

    Hey Conor,

    Agreed that sounds like a device failure especially with the ABA swap.  The most common cause for device failure in low voltage motor driver like this is an Overvoltage event - maybe when stopping the motor quickly the Back-EMF caused a momentary voltage higher than the Abs Max voltage of the device and caused it to break.  Or an ESD strike could damage it like this.  Sounds like pin damage or FET damage to me.

    Is 10uF your only bulk capacitance?  And what's the peak and continuous current of your motor?  You might need more like 20uF - 40uF depending. 

    With 5V VM I would be a little surprised if it got damaged with just stopping the motor but it's possible.  Can you take a scope capture when instantly stopping the motor and see how high VM pumps up to (if it goes up at all)?  Also just sanity check that the logic voltages are all within the device specs and don't go out of spec when starting/driving/stopping the motor. 

    Best,

    Jacob