Patent ID: 6025968
Filing Date: 2000-02-15
Classification: G11B

Abstract:
A data recording disk drive comprising:a data disk;a multiphase spindle motor having a winding for each phase and connected to the disk for rotating the disk;a transducer for writing data to or reading data from the disk;a carrier supporting the transducer;an actuator connected to the carrier for moving the carrier generally radially across the disk;a power removal response circuit responsive to the removal of power to the spindle motor;a full-wave rectifier circuit for converting back electromotive force from the spindle motor to current for the actuator when power to the spindle motor is removed;a first switch coupled between said power removal response circuit and the rectifier circuit and responsive to a first power-off signal from said power removal response circuit for directing a portion of the current from the freely rotating spindle motor to the actuator;a second switch coupled between said power removal response circuit and the rectifier circuit and responsive to a second power-off signal from said power removal response circuit for directing additional current from the freely rotating spindle motor to the actuator, the second power-off signal occurring a predetermined delay time after said first power-off signal; andan actuator resistor between the output of the rectifier circuit and the actuator, and wherein the first switch directs current from all of the spindle motor windings through the actuator resistor, the actuator resistor preventing a substantial portion of the current from the spindle motor windings from reaching the actuator.