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I have a stepper motor 28BYJ-48 rated 5 V and I want to use a DVR8825 driver so I can use the 1/32 micro-stepping feature. My problem is that DVR8825 has a minimum operating voltage of 8.2 V. Would the 28BYJ-48 stand a 10 V input?

Is there any alternative to the DVR8825 that operates at 5 V and has at least 1/32 micro-stepping?

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  • just because the DVR8825 uses a 10 V power supply, it does not mean that it necessarily delivers 10 V to the motor – jsotola Feb 24 at 7:52
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Stepper motors are rated in two different ways. Some provide a "rated voltage" in combination with a "DC resistance", others provide a "phase current" and a "phase resistance". The way they operate is identical.

Stepper motors such as your 28BYJ-48 are usually intended to be driven with a fixed voltage, their rated voltage. At this voltage, the maximum permittable current flows in the steppers windings - determined mostly by cooling and wire thickness. If you exceed that voltage, more current will flow and will damage / destroy the stepper motor.

The DRV8825 is a current controlled stepper motor driver - it always uses the full available supply voltage - 8.2V+ - but uses PWM to limit the current actually flowing in the stepper. This is possible because the stepper motor coils are inductors, which inhibit the flow of current.

To use your stepper motor with a DRV8825 driver, you'll have to calculate the steppers equivalent "maximum phase current". According to this datasheet, it's rated 5 V at 50 Ohms, giving us a current of 0.1 A. You can then set this current via the potentiometer on the driver chip. The Vref voltage should be set so that Vref = Imax / 2. Start at a Vref of 50 mV, and see how warm the motor gets and whether it's as strong as you would expect it to be.

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