Hi all,
I've designed a stepper driver. It works well with small motor. Now I'm using a 800 mA motor and I have a problem:
When power supply is ~10 V (after rectifier and diode a 9 V for DRV8825 chip) total current consumption is ~720 mA that means there is ~650 mA for motor.
When power supply is higher e.g. 12 V, 14 V, the power consumption is lower: 600 mA, 500 mA respectively and for higher value the motor doesn't want to run (or runs only a couple of steps and stops).
I'm using a pot with voltage regulator for current regulation and for all power supply voltages the voltage on the reference pins is equal 0,9V that means 818 mA current for motor using 0,22R sense resistors.
Have you any idea what is wrong?
Best regards,
Mikolaj