DRV8845EVM: stepper motor humming noise issue when we operate with DRV8845

Hello Dharmendra

Thank you for your question. 

Would you please share the motor resistance and inductance specifications. 

Also please share the Step mode, Full scale current value, Supply voltage, and step pulse PPS. 

Please also capture the current waveform for phase A .

Best regards, 

Mojtaba 

Step mode - 1/64

1) No of phase - 2

2) Phase voltage - 6.6V

3) Phase current - 1A

4 ) Phase resistance - 6.6ohms

5) Size : NEMA 17

The applied voltage on VM1 and VM2 pins is 11.5V.

The VREFX reference voltage pins are connected to PWM outputs of microcontroller for which the VOH logic level is 3.3V. 

We have used voltage divider ckt and adjusted VREF voltage of 1.47V on all VREFX pins.

All sense pins have 0.47 ohms 1 watt resistor to GND.

The maximum itrip calculated is ITRIPMax = VREF / (3 × RSENSE)

                                                                    = 1.47/(3 x 0.47) 

                                                                    = 1.04A

The maximum power to stepper motor is 6.6W as mentioned in the above motor specifications.

Hi Dharmendra, 

Thank you for sharing the information. 

The utep is set at 1/64. What is the target speed ( STEP PPS). 

can you capture the motor current waveform with us? 

Dharmendra Kanani said:

We have used voltage divider ckt and adjusted VREF voltage of 1.47V on all VREFX pins.

Are you using DRV8745EVM or you are using your own design? If  you are using the EVM the IFS can be set by GUI.

if you are using your own setup, is VREF fixed or PWMing. 

Are you running two motors at the same time? 

Please capture the motor current and share it with us. 

Best regards, 

Mojtaba