Product specifications

R01AN0168ED0101 Rev. 01.01 15
Application Note
Chapter 3 About Stepper Motor Movement
3.3 Recirculation of Inductance
Recirculation means performing a short-circuit on a stepper motor coil, during
the low-phase of the attached PWM. During the high-phase of the PWM the
output voltage drives a current through the coil, and during the low-phase, this
current of the coil, which represents an amount of energy, can be discharged
through the short-cut.
If recirculation is enabled, the PWM output of ISM performs a driving of the
output FET stages, which looks like this for a certain quadrant:
Figure 3-4 Inductive Output driving with Recirculation enabled
Obviously, the generated short-circuit by “~PWM(t)” avoids voltage peaks,
because the current i(t) can continuously discharge. If recirculation is switched
off, the disadvantage of the inductive voltage peak becomes obvious:
Figure 3-5 Inductive Output driving with Recirculation disabled