AN4158 datasheet(11/34 Pages) STMICROELECTRONICS

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DocID023635 Rev 2

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AN4158

Stepper motor basics

The microstepping driving technique results in less vibration and higher positioning

resolution. The magnetic field rotation corresponding to a full step is split into a sequence of

smaller rotations in the same number of the microstepping resolution. Each of these small

displacements causes a lower torque variation than a full step change (see Figure 5), so the

torque ripple is lower than in full step driving (smoother motion).

When this driving technique is used, the maximum output torque of the motor is lower than

the one obtained using the full step because the intensity of the stator magnetic field is lower

than a

2 factor.

Figure 5. full step driving versus microstepping motor torque

-56% IPeak

+83% IPeak

-38% IPeak

+92% IPeak

-20% IPeak

+98% IPeak

1. Compensated half step.

Table 4. Microstepping current level examples (continued)

1/2 step(1)

1/4 step

1/8 step

Phase A current

Phase B current

Microstepping

Full-step

max

Stat

AM15107v1

AN4158 Datasheet(PDF) 11 Page - STMicroelectronics