Patent ID: 7525268

Claim:
A control device for controlling a rotor of an electric motor that includes an inductive winding, said device comprising: first means for setting periods of time each centered on an instant of time in which a zero crossing of a current in the winding is expected; second means for generating a polarity signal that is representative of a polarity of the current in said winding in said periods of time, wherein said first and second means are suitable for providing samples of said polarity signal in said periods of time; counting means for producing a count resulting from counting said samples of the polarity signal in said periods of time; and further means having in input said count and being for deducing a distance between the instant of time in which the zero crossing of the current in the winding is expected an actual zero crossing instant of the current, said further means being for causing a phase shift between a driving voltage of the electric motor and a back electromotive force induced based on said distance.