DRV8825: DRV8825

Hello,

Do you have any scope captures showing the noise you are experiencing?  Voltage noise or current noise? 

Don't see any immediate issues with your schematic.

Regards,

Ryan

Hi Ryan,

Please find it from attachment. 

Hi,

Could you please share the current waveform? Either A or B is fine. Also the settings information will be helpful. VM = 12V. What is the IFS setting, is it full-step mode? What is the PPS input for STEP? Are you referring to audible noise from the motor? 

Thanks.

Regards, Murugavel

Hi,

We are using half step mode and PPS is 1KHz signal. 

Hi,

Please capture the current waveform and share with us. What is the IFS (full-scale current) setting? Generally speaking the whining audible noise at full, half or quarter microsteps cannot be avoided as the current waveform will have multiple fast edges in these modes. Higher microsteps would reduce the audible noise generated from the motor. Please confirm if your concern is with the audible noise generated in the stepper motor.

If lower audible noise is desired I'd recommend stepper drivers such as the DRV8426, DRV8434 with Smart Tune automatic decay modes and support up to 256 microsteps. Thanks.

Regards, Murugavel

Hi,

Thanks for your input, but we are using https://www.pololu.com/product/2133 this board with same firmware and no noise is observed, Could you please check the same and do the needful?

Are you seeing the same behavior with the same VREF voltage?  The VREF voltage set by your potentiometer determines the IFS (full-scale current) that Murugavel mentioned.  

An oscilloscope capture of the current waveform will help us a lot. Just put a current probe around 1 wire to the motor, such as A1.  

Also please post your PCB layout (pictures/pdf is fine, Altium source best) 

Here is the Pololu Schematic, looks nearly identical to yours, so still not schematic issue. 

Where did you purchase your DRV8825 parts from?  TI's store or Digikey/Mouser? Want to make sure it is legitimate.  

Best,

Jacob

Hi Jacob,

Yes, VREF is same in both boards, and testing scenario/batch is also same.

Waveform is attached to this reply, for PCB layout - Could you please provide email ID so I can share it over email? We cant share full board design at open forum. 

We purchased this IC from Digikey. 

. 

Hello,

Just to summarize this issue.  

1)  You have purchased a Pololu EVM and with exactly the same settings in terms of VREF and micro-stepping mode, you see no issues?  Correct?

2)  You have built your own board and see issues with same settings as Pololu?  Correct?

Can you please send us his the part marking from the top of the ICs and where you purchased the parts?

Can you please send a current waveform, not voltage, of current in one of the coils?

Regards,

Ryan

Dear Ryan Kehr

#1: Yes

#2: Yes

#3: DRV 8825
2ATG5
 C118

These are the markings

We will gather the current waveform and send it to you shortly.

Neel,

Thank you for sharing.  That is a valid device.  Will look forward to your current waveforms.

Regards,

Ryan