Stmicroelectronics S.r.l.

Fabio Ramaioli

Alberto Salina

Gianluca Ventura

Alessandra Schenone

Luca Anostini

A disk drive system is described which includes a disk having a magnetic surface and a motor for rotating the disk, a magnetic head being movable relative to said magnetic surface. The motor generates a back electromotive force voltage having different phases and the system comprising a plurality of switches for switching the back electromotive force voltage, a control circuit to control the plurality of switches to supply the back electromotive force voltage to direct the head to a parking position. The system also comprises a comparator adapted to compare a single phase of the back electromotive force voltage with the sum of the other phases of the back electromotive force voltage. The comparator generates an output signal representative of the comparation and the system comprises a logic block controlled by the output signal of the comparator. The logic block is adapted to determine time periods and a control sequence of the switches which is associated to the time periods. The control sequence is supplied to the control circuit so that the last generates control signals to control the plurality of switches.

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Melegnano, Italy

Fabio Ramaioli