Koninklijke Philips Corporation N.v.

U.S. Philips Corporation

Henricus Marinus Van Hout

Emeric Uguen

Jannis Pieter Van Der Linde

Johannes Petrus Maria Bahlmann

Henricus Cornelis Johannes Buthker

A device for controlling a motor intended to set an arm provided with a head for reading/writing information in motion with respect to a surface carrying information. The device having a controller for enabling the power supply of the winding of the motor to be managed and a measurer for measuring the value of a counter-electromotive force induced in the winding by the movement of the rotor when the power supply of the winding is interrupted. This device enables the angular speed of the arm to be measured and controlled during an emergency return phase of the arm towards a rest position.

Motor-control device enabling the rotational speed of the motor's rotor to be measured

Method of energizing a polyphase motor having an increased energy efficiency

A control unit ( ) according to the invention for controlling a brushless motor ( ) includes position detection means ( ) for generating a signal (S ) which is indicative of the position of the motor ( ). The control unit ( ) further includes supply means ( ) for energizing two or more coils ( ) of the motor ( ) and output terminals ( ) for electrically coupling the coils ( ) to the supply means ( ). The position detection means ( ) include polarity detection means (T , D , T , D , A ) for generating a polarity signal (S ) which is a measure of the direction of the current (Ia) through at least one of the coils ( ). The control unit ( ) in accordance with the invention is particularly suitable for use in a device for reading and/or writing an information carrier ( ).

Control unit for a brushless motor and read/write device including such a control unit

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Eindhoven, Netherlands

Henricus Marinus Van Hout