DRV8711: DRV8711 drive motor

Hi Annie,

I have a couple questions:

• Is the customer using their own custom board or the DRV8711 EVM?
• If custom board, can the customer provide schematic/layout? (can send via private message if customer don't want to share publicly)
• Can the customer provide a scope shot of the nFAULT pin when the noise is heard? (noise could be from UVLO triggering)
• What are the register settings before and after the drive configurations changed?

Hi Pablo Armet,

I have sent the private message to you. Would you help to check it?

Thanks.

Annie

Hi Annie,

I have received your private message and I am currently reviewing it.

In the meantime, can you kindly confirm if what I am saying below is true (please correct me if my assumptions are incorrect) :

• The customer is observing noise coming from the motor when the motor is stopped while rotating, correct?
• There is no PWM wave input on the STEP input after the motor has stopped, correct?
• When motor is stopped before ANY PWM signals are sent to the STEP input, there is no audible noise, correct?
• The customer wants to know why there is noise when the motor is stopped while it was rotating, correct?

Thank you!

Hi Pablo,

The motor will stalled at different frequencies. The motor is not stalled at 6khz and 10khz. However, when it is lower than 10khz, the stall will occur and the motor will still rotate. It is not a fault alarm, and the motor will heat up after a long time of stopping. He used 2.8A motor. According to the manual calculation, the current is 1.7A.

• The customer is observing noise coming from the motor when the motor is stopped while rotating, correct?
  • After the rotation stops, he can hear the slight noise by holding the motor to his ear.
    
• There is no PWM wave input on the STEP input after the motor has stopped, correct?
  • Yes, there is no PWM wave.
• When motor is stopped before ANY PWM signals are sent to the STEP input, there is no audible noise, correct?
  • Yes.
• The customer wants to know why there is noise when the motor is stopped while it was rotating, correct?
  • There is noise after stopping, there is no sound when stopping the motor with another drive.

Thanks.

Annie

Hi Annie,

[Q]: Can the customer provide a picture of their set-up?

[Q]: Can the customer provide a screenshot of the output PWM signals and FAULTn when the motor is stopped with frequency below 10kHz and above 10kHz?

[Q]: can the customer provide a scope shot of the PWM signals of at least two outputs when the audible noise is heard from the motor? It could be that the motor is holding current which can lead to some audible noise.