Abstract: A battery including a housing that contains at least one cell, a current limiter and a control circuit. When a device is first connected to the battery, the control circuit actuates the current limiter so that only a current limited voltage is sourced to the device. This current limited signal only supplies sufficient current for energizing a circuit internal to the device. This current limited signal is not able to power the device. The control circuit waits to receive if the powered on device transmits a recognition code. If the recognition code is received, the control circuit sources current to from the cell to the device along a path that bypasses the current limiter. This current, not being current limited is able to power the components internal to the connected device.

Abstract: A battery including a housing that contains at least one cell, a current limiter and a control circuit. When a device is first connected to the battery, the control circuit actuates the current limiter so that only a current limited voltage is sourced to the device. This current limited signal only supplies sufficient current for energizing a circuit internal to the device. This current limited signal is not able to power the device. The control circuit waits to receive if the powered on device transmits a recognition code. If the recognition code is received, the control circuit sources current to from the cell to the device along a path that bypasses the current limiter. This current, not being current limited is able to power the components internal to the connected device.

Abstract: Method and apparatus for compensating for a decrease in the torque constant of an actuator motor in a data storage device. An actuator supports the head adjacent a data recording surface on which a plurality of tracks are defined. A servo circuit outputs current to the actuator motor to carry out a seek to move the head from an initial track to a destination track in accordance with a velocity profile having a nominal deceleration trajectory along which the head is decelerated to reach the destination track. The servo circuit operates to adjust an initial value of gain to a second value in response to a selected parameter, and scales the nominal deceleration trajectory to a derated deceleration trajectory in relation to the second value of the gain. The derated deceleration trajectory is preferably selected in relation to the difference between the second value of gain and a predetermined threshold.

Abstract: Method and apparatus for compensating for a decrease in the torque constant of an actuator motor in a data storage device. An actuator supports the head adjacent a data recording surface on which a plurality of tracks are defined. A servo circuit outputs current to the actuator motor to carry out a seek to move the head from an initial track to a destination track in accordance with a velocity profile having a nominal deceleration trajectory along which the head is decelerated to reach the destination track. The servo circuit operates to adjust an initial value of gain to a second value in response to a selected parameter, and scales the nominal deceleration trajectory to a derated deceleration trajectory in relation to the second value of the gain. The derated deceleration trajectory is preferably selected in relation to the difference between the second value of gain and a predetermined threshold.

Abstract: Method and apparatus for reducing repeatable runout signals in a servo position error (SPE) signal of a disc drive actuator. During track following, a measurement estimate is obtained through the sampling and accumulating of data from the SPE over a mechanical revolution of the drive, the measurement estimate providing a characterization of the repeatable runout signal in the servo position error signal. A correction estimate is updated by the measurement estimate, and the correction estimate is added to the servo position error signal to provide an adjusted servo position error signal. The disc drive uses the adjusted servo position error signal to generate a correction signal for adjusting the position of the actuator. The measurement estimate is reset after each update of the correction estimate and a new measurement estimate is generated during each subsequent rotation of the disc drive during track following mode.

Abstract: A method of measuring the read-to-write offset of a track in a disc drive system having separate read and write elements measures the amplitude of a test signal across the width if a track. A test pattern is written to the track at a predetermined actuator offset, which will typically be zero. Next, the read element is incrementally moved across the width of the track to measure a maximum amplitude in the read signal from the read element. After the maximum amplitude has been determined, the read element is incrementally moved across the width of the track to find first and second actuator offset positions where the read signal has an amplitude approximately equal to a predetermined percentage of the maximum amplitude. A midpoint is calculated between the first and second actuator offset positions, and the read-to-write offset is equal to the difference between the midpoint and the predetermined actuator offset.

Abstract: A method for following a selected data track on a selected data surface of a disc drive of the type having a dedicated servo system in which guiding of data heads to follow data tracks on data surfaces is effected by positioning an actuator upon which the data heads are mounted in relation to the location of a servo head, also mounted on the actuator, with respect to servo tracks on a dedicated servo surface. The data tracks are organized into cylinders, each containing a servo track, and a selected data track is accessed by seeking to an optimum servo track displaced from the servo track in the cylinder containing the data track by an integral number of track spacings selected to compensate for misalignments greater than a track spacing between the data and servo heads. Data track following is then effected by offsetting the servo head from the optimum servo track to compensate for misalignments of less than a track spacing between the data and servo heads and tracks.

Abstract: Method and apparatus for dynamically compensating for servo burst measurement offsets in a disc drive. A first type of servo position error signal is used during a compensation routine to position a head adjacent a selected track on a disc, the first type of servo position error signal determined from servo burst signals read by the head from servo position fields on the disc. A second type of servo position error signal is also generated from the servo burst signals and the difference between selected values of the second type of servo position error signal is compared to an acceptance limit. Compensation terms are incrementally added to the servo burst signals used to generate the second type of servo position error signal until the difference is below the acceptance limits. Thereafter, the compensation terms are stored and retrieved during normal track following operations to generate a compensated servo position error signal.

Abstract: A hard disc drive having a digital servo system for controlling the position of a servo head on a dedicated servo surface. The servo surface is formatted in a series of consecutive frames along concentric tracks, each frame passing the servo head in a time that defines a sampling interval for the servo system. The frames contain track address and position fields for locating the servo head and location can be effected in relation to limited or extended fine control regions about the tracks via signals transmitted to a position circuit utilized to generate a servo position error from the position field. The position circuit generates a track phase code for checking track addresses generated by a track address circuit used to generate a track address from the address field.