公开(公告)号：JPH11250601A

公开(公告)日：1999-09-17

申请号：JP35343298

申请日：1998-12-11

Applicant: ST MICROELECTRONICS INC

Inventor： MICHAEL W NARU ,  CAROBOLANTE FRANCESCO ,  SCHLAGER KARL M

IPC: G11B21/12 ,  G11B5/54

Abstract: PROBLEM TO BE SOLVED: To prevent damage of head, disk and recording information by moving first the head toward the internal diameter of recording medium, then toward the external diameter and finally stopping on a lamp located at the external diameter. SOLUTION: At the time of parking a head 40, a control current being supplied to an actuator motor 16 is usually cut off and a drive current is then supplied to the actuator motor 16 from a driver circuit 150 supplying the drive current to a 3-phase DC brushless spindle motor. First, the head 40 is moved in the internal diameter direction of disk 18 until an actuator arm 14 is in contact with an internal side crush stop 56. Next, the driver circuit 150 supplies a high voltage to drive the spindle motor to the actuator motor 16 and the head 40 is located at the flat part of lamp 60 considering amount of movement to be accumulated while the head 40 moves to the external diameter 54 crossing the disk 18.

公开(公告)号：DE69330998T2

公开(公告)日：2002-04-04

申请号：DE69330998

申请日：1993-12-16

Applicant: ST MICROELECTRONICS INC

Inventor： CAROBOLANTE FRANCESCO

IPC: H03K17/08 ,  H03K17/082 ,  H03K17/567 ,  H03K17/64 ,  H03K3/0233

Abstract: A circuit for increasing the reverse breakdown voltage of a bipolar transistor (34) that provides drive current to an inductor (31) has a voltage control transistor (40) connected between the collector and base of the bipolar transistor (34), having a control element connected to one end of the inductor (31). The circuit can be fabricated as a portion of an integrated circuit formed on a single semiconductor substrate. Also disclosed is a method for increasing the emitter-collector breakdown voltage of a bipolar transistor (34) in which the base and collector of the bipolar transistor (34) are shorted when the emitter-collector voltage exceeds the breakdown voltage by turning on a transistor (40) connected between the base and collector of the bipolar transistor (34).

公开(公告)号：DE69326963T2

公开(公告)日：2000-02-17

申请号：DE69326963

申请日：1993-12-16

Applicant: ST MICROELECTRONICS INC

Inventor： CAROBOLANTE FRANCESCO ,  CAMERON SCOTT W

IPC: H02P6/06 ,  H02P6/18 ,  H02P6/14

公开(公告)号：DE69322298T2

公开(公告)日：1999-05-06

申请号：DE69322298

申请日：1993-02-22

Applicant: ST MICROELECTRONICS INC

Inventor： CAROBOLANTE FRANCESCO ,  ROHRBAUGH MARK E

IPC: H02P6/16 ,  H02P6/18 ,  H02P6/00

Abstract: A circuit and method for detecting when the back emf of a motor coil passes a predetermined level includes circuitry for providing a voltage proportional to the back emf of the motor coil, and circuitry for providing a voltage proportional to a reference potential. A first bias voltage is added to the voltage proportional to the back emf to produce a first added voltage, and a second bias voltage os added to the reference potential when the back emf of the motor coil is expected to change in a predetermined direction to produce a second added voltage. A comparator produces an output change when the first added voltage becomes larger than the second added voltage at the predetermined level.

公开(公告)号：DE69330998D1

公开(公告)日：2001-11-29

申请号：DE69330998

申请日：1993-12-16

Applicant: ST MICROELECTRONICS INC

Inventor： CAROBOLANTE FRANCESCO

IPC: H03K17/08 ,  H03K17/082 ,  H03K17/567 ,  H03K17/64 ,  H03K3/0233

Abstract: A circuit for increasing the reverse breakdown voltage of a bipolar transistor (34) that provides drive current to an inductor (31) has a voltage control transistor (40) connected between the collector and base of the bipolar transistor (34), having a control element connected to one end of the inductor (31). The circuit can be fabricated as a portion of an integrated circuit formed on a single semiconductor substrate. Also disclosed is a method for increasing the emitter-collector breakdown voltage of a bipolar transistor (34) in which the base and collector of the bipolar transistor (34) are shorted when the emitter-collector voltage exceeds the breakdown voltage by turning on a transistor (40) connected between the base and collector of the bipolar transistor (34).

公开(公告)号：DE69326963D1

公开(公告)日：1999-12-09

申请号：DE69326963

申请日：1993-12-16

Applicant: ST MICROELECTRONICS INC

Inventor： CAROBOLANTE FRANCESCO ,  CAMERON SCOTT W

IPC: H02P6/06 ,  H02P6/18 ,  H02P6/14

公开(公告)号：DE69322298D1

公开(公告)日：1999-01-14

申请号：DE69322298

申请日：1993-02-22

Applicant: ST MICROELECTRONICS INC

Inventor： CAROBOLANTE FRANCESCO ,  ROHRBAUGH MARK E

IPC: H02P6/16 ,  H02P6/18 ,  H02P6/00

Abstract: A circuit and method for detecting when the back emf of a motor coil passes a predetermined level includes circuitry for providing a voltage proportional to the back emf of the motor coil, and circuitry for providing a voltage proportional to a reference potential. A first bias voltage is added to the voltage proportional to the back emf to produce a first added voltage, and a second bias voltage os added to the reference potential when the back emf of the motor coil is expected to change in a predetermined direction to produce a second added voltage. A comparator produces an output change when the first added voltage becomes larger than the second added voltage at the predetermined level.