Control device of a motor electronically commutated by means of a position signal

The invention relates to a device for controlling an electronically commutated motor comprising: - an encoder (2) comprising a main multipolar track (2a) and a multipolar track (2b) so-called "top turn" - a sensor (3) fixed delivering two digital position signals (a, B) and a top turn signal (C); - a current switching circuit in the motor phase windings which comprises 2 * P * N switches; - a control circuit switching circuit which is adapted to provide switching signals for the switches that correspond to the state of the logic determined by the top tour signal (C) or by the position signals (a, B) .L'invention also relates to a bearing and an engine equipped with such a device and a method of controlling such an engine.