Abstract: A circuit includes a driver circuit having a high side switch device and a low side switch device coupled to a load voltage node and a motor winding output. A controller operates the high side switch device and the low side switch device. The controller operates in a normal mode to supply current to the motor winding output for driving a motor winding when an external power supply is available to supply the load voltage node. In response to detecting a loss of the external power supply, the controller operates the high side switch device and the low side switch device in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor winding to supply current to the load voltage node.

Abstract: A circuit includes a driver circuit having a high side switch device and a low side switch device coupled to a load voltage node and a motor winding output. A controller operates the high side switch device and the low side switch device. The controller operates in a normal mode to supply current to the motor winding output for driving a motor winding when an external power supply is available to supply the load voltage node. In response to detecting a loss of the external power supply, the controller operates the high side switch device and the low side switch device in a boost mode to utilize a back electromotive force (BEMF) voltage from the motor winding to supply current to the load voltage node.

Abstract: Method and apparatus for controlling a brushless dc motor, such as the type used in a data storage device to rotate data storage media. A sequence of drive pulses is applied to rotate the motor. The sequence is switched from first to second motor commutation states at a time determined in relation to changes in elapsed time between successive pulses in the sequence. Each drive pulse has a duration established in relation to an inductance of the motor, and is separated from adjacent pulses by an intermediate delay of predetermined value. A peak elapsed time interval between successive pulses is identified, and the next commutation state is switched in at a selected time after the peak time interval. The sequence preferably accelerates the motor from rest to an intermediate velocity, after which back electromotive force (bemf) commutation is used to accelerate the motor to a final operational velocity.

Abstract: Method and apparatus for accelerating a motor from an intermediate velocity to a final operational velocity. The motor is accelerated from rest to the intermediate velocity through application of fixed duration drive pulses to the spindle motor. Once the motor reaches the intermediate velocity, commutation circuitry and back electromotive force (bemf) detection circuitry use detected bemf from the motor to electronically commutate the motor to accelerate to the final operational speed. A phase lock oscillator (PLO) attempts to acquire frequency lock for the motor. A control circuit measures the current in the motor to evaluate the effectiveness of the phase lock. If the measured current is found to be above a threshold value, the motor is restarted.

Abstract: Method and apparatus for detecting head landings on a data zone of a data storage disc. A disc drive includes an actuator which controllably positions a head adjacent a disc and nominally retracts the head to a parked position when the drive is deactivated. The actuator moves in response to current applied to an actuator coil immersed in a magnetic field. During disc drive initialization, the disc is accelerated to a velocity sufficient to allow the head to be aerodynamically supported over the disc, and current is passed through the actuator coil to urge the head toward the parked position. The current is monitored to detect generation of a back electromotive force (bemf) voltage induced by movement of the coil. An error condition is logged indicating that an initial position of the head was over a data zone of the disc when bemf voltage is detected.

Abstract: Method and apparatus for initializing a disc drive to bring a spindle motor to a final, operational velocity after a disc drive processor reset condition. The spindle motor is rotated using electronic commutation and back electromotive force (bemf) detection. Upon initialization of the disc drive, a control circuit checks for the presence or absence of detected bemf. The absence of bemf indicates the spindle motor is either at rest or is rotating at a relatively low velocity. In the absence of bemf, the electrical rotational position of the spindle motor is determined, a short braking pulse is applied to the motor, and rotation of the spindle motor is detected in relation to changes in the electrical rotational position. Further breaking pulses are applied until no apparent change in electrical rotational position is detected, after which the spindle motor is accelerated from rest to the final, operational velocity.

Abstract: Method and apparatus for accelerating a motor from an intermediate velocity to a final operational velocity. The motor is accelerated from rest to the intermediate velocity through application of fixed duration drive pulses to the spindle motor. Once the motor reaches the intermediate velocity, commutation circuitry and back electromotive force (bemf) detection circuitry use detected bemf from the motor to electronically commutate the motor to accelerate to the final operational speed. A phase lock oscillator (PLO) attempts to acquire frequency lock for the motor. A control circuit measures the current in the motor to evaluate the effectiveness of the phase lock. If the measured current is found to be above a threshold value, the motor is restarted.

Abstract: Method and apparatus for detecting head landings on a data zone of a data storage disc. A disc drive includes an actuator which controllably positions a head adjacent a disc and nominally retracts the head to a parked position when the drive is deactivated. The actuator moves in response to current applied to an actuator coil immersed in a magnetic field. During disc drive initialization, the disc is accelerated to a velocity sufficient to allow the head to be aerodynamically supported over the disc, and current is passed through the actuator coil to urge the head toward the parked position. The current is monitored to detect generation of a back electromotive force (bemf) voltage induced by movement of the coil. An error condition is logged indicating that an initial position of the head was over a data zone of the disc when bemf voltage is detected.

Abstract: Method and apparatus for accelerating a disc drive spindle motor from rest to a final operational velocity. During a low gear mode, the spindle motor is accelerated from rest to a first velocity through application of fixed duration drive pulses to the spindle motor. A high gear mode is next employed to accelerate the spindle motor from a first velocity to an intermediate velocity. Variable duration drive pulses are applied to the spindle motor each having a duration selected as a percentage of the duration of the most recently detected commutation period of the spindle motor. Once the spindle motor reaches the medium speed, commutation circuitry and back electromotive force (bemf) detection circuitry use detected bemf from the spindle motor to electronically commutate the motor to accelerate to the final operational speed.

Abstract: Method and apparatus for initializing a disc drive to bring a spindle motor to a final, operational velocity after a disc drive processor reset condition. The spindle motor is rotated using electronic commutation and back electromotive force (bemf) detection. Upon initialization of the disc drive, a control circuit checks for the presence or absence of detected bemf. The absence of bemf indicates the spindle motor is either at rest or is rotating at a relatively low velocity. In the absence of bemf, the electrical rotational position of the spindle motor is determined, a short braking pulse is applied to the motor, and rotation of the spindle motor is detected in relation to changes in the electrical rotational position. Further breaking pulses are applied until no apparent change in electrical rotational position is detected, after which the spindle motor is accelerated from rest to the final, operational velocity.

Abstract: Method and apparatus for accelerating a disc drive spindle motor from rest to a final operational velocity. During a low gear mode, the spindle motor is accelerated from rest to a first velocity through application of fixed duration drive pulses to the spindle motor. A high gear mode is next employed to accelerate the spindle motor from a first velocity to an intermediate velocity. Variable duration drive pulses are applied to the spindle motor each having a duration selected as a percentage of the duration of the most recently detected commutation period of the spindle motor. Once the spindle motor reaches the medium speed, commutation circuitry and back electromotive force (bemf) detection circuitry use detected bemf from the spindle motor to electronically commutate the motor to accelerate to the final operational speed.

Abstract: An apparatus and method for performing voltage margin testing in an integrated circuit device. The device is provided with an embedded voltage source having a voltage regulator which outputs a regulated analog voltage at a nominal magnitude, such as +3.3 volts. A voltage monitor provides an indication when the regulated analog voltage varies from the nominal magnitude by an output tolerance range determined as a first selected percentage of the nominal magnitude. An adjustment circuit applies a voltage regulator adjustment signal to the voltage regulator to adjust the regulated analog voltage by a second selected percentage of the nominal magnitude. The adjustment circuit further provides a voltage monitor adjustment signal to the voltage monitor to concurrently adjust the output tolerance range to a third selected percentage of the nominal magnitude different from the first selected percentage.