How to Choose the Stepper Drive

When choosing stepper motor drivers, also known as controllers, several factors must be taken into consideration. Buyers should make sure that the motor is compatible with the driver, as there are several different types. The number of wires in the motor determines whether a bipolar or unipolar driver is required. Maximum current input and output of the motor also impact which driver to buy, as do features such as step modes, step frequency, and protection circuitry.

Step 1:  Select the voltage range

Select an operating voltage range that gives you enough margin to deal with supply pumping (when the motor acts as a generator pumping current into the supply, temporarily raising the voltage) and the various inductive spikes that occur when driving a motor.  The typical rule of thumb for a stepper is to have ~ 20% margin vs. the operating supply voltage of the motor, but depending on the use model of the motor,you may need up to 2x margin, although this is more an extreme case.  For brushed DC and brushless DC motors, it’s more like 1.5x to 2.5x margin. Base your selection on the recommend operating voltage range, not the total voltage.

Step 2: Select the current rating 

Stepper drivers typically drive sinusoidal currents, so consider your peak and RMS current requirements and select a driver that can handle both.  An integrated motor driver’s RMS current rating is a function of thermal performance, I.E. how much current can it handle before shutting down due to the over-temperature protection kicking in.  Typically, the higher the current, the lower the FET RDSON required.   Other variables affecting thermal performance include how efficient the FETs switch and how thermally efficient the package is at getting the heat out.  For a stepper driver, the peak current is typically set at 1.414 of the RMS current.

Step 3: Determine board space and thermal requirements

Integrated motor drivers are your smallest option, but they can’t handle as much current as a pre-driver with external FETs.  Integrated drivers also typically dump the majority of the heat into the board, so if you have a really small board, make sure it can reliably handle the heat. Look for lower RDSON ratings if you are concerned about thermal performance and for high current applications consider a pre-driver with external FETs.

Recommend Leadshine Stepper Drives

Leadshine offers three main series of stepper drives, the advanced digital EM series, digital DM series, and classic M series. The EM series stepper drives are 32-bit DSP-based and adopt Leadshine's latest stepper control technology with many advanced features. The high performance leadshine m542 are featured with extra low noise, very low motor heating, and ultra smooth motor movements at low speed. With performance and costs balanced, Leadshine's M series stepper drives adopt pure sinusoidal control technology & anti resonance, and can offer excellent high speed performance.

Highlights

    2 phase or 3 phase

    20-80 VDC input, or direct 120/230 AC input

    Step & direction control, CW/CCW, or 0-5 DC for speed control

    Capable of driving NEMA 8 to 50 stepper motors

    Digital or analog

    Anti Resonance for excellent performance

    Low cost and high quality

    CE and/or UL/CUL certified

Conclusion

To choose the correct stepper drive, buyers must consider their budget, the intended application of the stepper motor, and the required features. Buyers should ascertain which drives are compatible with the motor in question, since some motors will not work with an incorrect drive. The required features are also important considerations.