Abstract: A self-contained disk drive actuator velocity controller for, independently of the disk drive microprocessor, placing the actuator into a velocity mode to slew the actuator to a pre-programmed velocity during parking, unparking, power interruption or microprocessor malfunction. The velocity controller may place the actuator into the velocity mode in response to a timeout signal that is generated in the event the microprocessor fails to update the current demand DAC within a predetermined timeout interval. The velocity controller may also place the actuator into the velocity mode in response to a supply power loss. In addition, the velocity controller may be triggered in response to a command from the microprocessor to park or unpark the actuator. The velocity controller monitors the BEMF generated by the actuator motor coil and adjusts the gain of the actuator motor driver accordingly until BEMF reaches a value that corresponds to the target velocity.

Abstract: A head stack assembly for a disk drive includes a swing-type structure, a head gimbal assembly, and a coil. The swing-type structure has a bore defining a bore axis. The head gimbal assembly is cantilevered from the swing-type structure to project radially away from the bore axis. The head gimbal assembly includes transducing structure for writing to and reading from the recording surface of a disk. The coil is cantilevered from the swing-type structure to project radially away from the bore axis in a direction opposite from the head gimbal assembly. The coil has a shape to provide a current flow path that includes first and second multi-leg portions that are spaced from each other in a direction parallel to the bore axis.

Abstract: A disk drive has a microprocessor, a digital controller chip, and an analog power chip, and a multi-winding spindle motor. The power chip operates under gross and fine control to connect and disconnect, during ON and OFF phases, a supply voltage to each winding on a PWM basis. The magnitude of the supply voltage and the temperature of the power chip vary. The microprocessor sends a digital control signal to the controller chip for gross control. The controller chip sends a PWM signal to the power chip for fine control. The power chip has pins for receiving the supply voltage, for sending a modulated signal to the controller chip; and for receiving the PWM signal from the controller chip.

Abstract: A head disk assembly for a hard disk drive employs a rotary actuator apparatus including a pivot shaft that defines an actuator axis of rotation. A pivot bearing assembly including a pivot bushing having a plurality of fingers supports rotation of the actuator about the pivot shaft. Each of a plurality of fingers has a bearing end that is in sliding contact with the pivot shaft. The fingers are formed from a material in a shape that provides the stiffness and low coefficient of friction necessary for the desired pivot bearing performance.

Abstract: An intelligent hard disk drive, which includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA), has a thin configuration. The HDA includes a spindle motor and the PCBA includes spindle motor driver circuitry. Spring loaded contacts and exposed electrical contacts provide automatic electrical connection between the spindle motor and the spindle motor driver circuitry.

Abstract: An air bearing slider having debris removing channels for a hard disk drive. An air bearing slider contains a center pad having multiple longitudinal debris channels cut therein approximately 1-3 microns wide and approximately 1-3 microns deep and spanning the entire length of the air bearing surface of the center pad. The debris channels are effective for collecting small sized debris and passing them through the channel length and out the trailing end of the center pad. By this action, the debris are prevented from collecting along the edges, corners and on the top surface of the center pad or on and around the transducer situated on the center pad. By reducing debris in these locations, the debris does not alter the flying height of the slider with respect to the surface of the disk. Therefore, by eliminating debris around the transducer, this invention eliminates errors caused by the debris and thereby provides a more reliable disk drive.

Abstract: A head disk assembly ("HDA") comprises an enclosure including a base and a pivot bearing cartridge having a shaft and a outer shell rotatable about the shaft. The outer shell has a cylindrical surface. The shaft is affixed to the base at a predetermined location. The enclosure has an internal volume with a limited height above the predetermined location. The cartridge has an elongated portion in the volume, the elongated portion having a height approximately equal to the limited height. The HDA further comprises a plurality of rotating disks, each having at least one recording surface. The HDA further comprises an arm stack comprising a plurality of arms, and a plurality of head gimbal assemblies. Each arm has a stacking portion and a cantilever portion. Each head gimbal assembly has one end attached to the cantilever portion of a respective arm and has an opposite end positioned adjacent a recording surface.

Abstract: A pivot bearing assembly for mounting to an enclosure of a head disk assembly to support a head stack assembly of a disk drive is disclosed. The pivot bearing assembly comprises a shaft for being affixed to the enclosure and defining a longitudinal axis, a first and second set of bearings, the second set of bearings longitudinally spaced from the first set of bearings, and each set of bearings surrounding a respective portion of the shaft. The pivot bearing assembly also comprises an inner sleeve member and an outer sleeve member, both sleeve members surrounding the shaft. A pair of channels is located between the outer and inner sleeve members. Alternatively, the pair of channels is located between the shaft and the sets of bearings. The channels contain a cured cast-in-place material, preferably, an ultra violet cured polyurethane compound having a hardness between approximately 24 Shore A to 79 Shore A.

Abstract: An actuator coil for a disk drive is formed of materials and processed in a manner such that the amount of outgassing that occurs in normal operation of the disk drive is minimized. An insulative coating, such as polyurethane which is rated well above the normal operating temperature is first applied to drawn copper wire. Then, a polyamide bond coating was used to cover the insulative coating. Next, a lubricant having a low average molecular weight was selected. The resulting wire was then wound to form the actuator coil. The coil is then cured at a high temperature for an extended length of time to drive off solvents and allow the polymers to crosslink and stabilize.

Abstract: A disk drive preamplifier unit includes a serial interface circuit for receiving serially formatted control signals from an associated disk drive controller. The control signals contain several types of information, including head select, write current magnitude, bias for MR transducers, gain magnitude for a variable gain amplifier, and test and mode information. The preamplifier unit incorporates several test circuits in addition to the usual write unsafe detector circuit, and a multiplexer controlled by the mode control signals from the serial interface unit is used to select which test circuit or detector is coupled to a common test output terminal whose signals are coupled back to the controller for further processing.

Abstract: A disk drive includes a disk, a magnetic transducer, and a rotary actuator arrangement for positioning the magnetic transducer over a selected area of the disk. The rotary actuator arrangement includes a head stack assembly including a body portion and a plastic arm having an arm surface, a first end and a distal end, with the first end being attached to the body portion. The head stack assembly further includes a load beam for supporting the transducer. The load beam has a plurality of mounting sites, an arm-facing surface, and a retention surface. The head stack assembly further includes a plurality of plastic binding structures that secure the load beam to the arm. Each plastic binding structure has a shaft portion projecting through a respective one of the mounting sites, has a bonding portion forming a homogeneous plastic bond with the arm surface, and has a retention portion abutting the retention surface; whereby the load beam is securely attached to the plastic arm.

Abstract: A disk drive circuit that includes a configuration resistor, a reference resistor, a capacitor and a processor. The processor is mounted on a first circuit assembly in the disk drive, such as the controller circuit board, and the configuration resistor is mounted on a second circuit assembly, such as the head-disk assembly (I-IDA). The resistance of the configuration resistor corresponds to the configuration of the second circuit assembly. The configuration may represent the number of heads or the type of preamplifier in the IDA. The processor calculates the resistance of the configuration resistor to determine the configuration of the second circuit assembly in the following manner. The processor charges the capacitor. The processor then allows the capacitor to discharge through a first circuit that includes both the configuration resistor and the reference resistor and measures the discharge time or time constant. The processor again charges the capacitor.

Abstract: An intelligent disk drive employing a controller which performs high speed error correction and miscorrection detection using a finite field processor. The error correction code is defined over a finite field and the error detection code is defined over an extension field of the finite field. The finite field processor performs calculation over both the finite field and extension field to provide high speed error correction and correction validation.

Abstract: An intelligent disk drive having error detection and correction capability employs an embedded error correction controller with a pipelined architecture for performing error correction under program control. The pipelined architecture provides parallel operand fetching and instruction execution for high speed operations during error correction.

Abstract: A start-up controller is programmed to continuously monitor the start-up acceleration of a motor using a stored acceleration profile to check the acceleration time against specification limits for the particular motor in which the controller is incorporated. The acceleration profile is an ordinal series of acceleration profile points in which each point is associated with a profile motor speed and a profile elapsed time. The controller terminates the acceleration of the motor if overall time elapsed since the start of acceleration is greater than the profile elapsed time associated with a profile point that is designated by the motor speed.

Abstract: A vibration decoupler for a swing-type head actuator pivot bearing assembly in a disk drive. The invention selectively decouples axial actuator vibrations from the pivot shaft while retaining the radial and rotational rigidity needed to ensure head positioning precision. The head stack assembly is rigidly coupled to the pivot bearing shaft in the radial and rotational dimensions and is pliably coupled to the same shaft in the axial dimension. This decoupling scheme eliminates most acoustic vibration components created in the rotary actuator. Axial decoupling eliminates most acoustic vibration components transmitted from the pivot shaft to the drive housing. The vibration isolator may be fabricated as a single piece of injection-molded plastic, including all necessary elements for coupling to the pivot bearing and the actuator body.

Abstract: A disk drive has a base, a cover, a spindle motor mounted to the base, and a disk coupled to the spindle motor. A rotary actuator comprising a head stack assembly is coupled to the base by a pivot bearing assembly. The pivot bearing assembly provides a stationary member, a bearing, and a sleeve member for rotatably supporting the actuator. The pivot bearing assembly further provides an elastomeric interface between the stationary member and the actuator such that vibratory motion imparted to the head stack assembly is dampened by the elastomeric interface.

Abstract: An integrated circuit for a disk drive that includes a sucessive-approximation analog-to-digital converter (ADC) with a two-stage digital-to-analog converter (DAC) and may also include a servo demodulator. The circuit may be implemented in a basic or pure-digital CMOS chip because the ADC includes no precision analog elements such as resistors and capacitors. The first DAC stage operates on the most significant group of bits, and the second DAC stage operates on the least significant group of bits. The DAC includes a reference current source. The first DAC stage is a multiplying DAC that multiplies the reference current in response to its digital input, and the second stage is a dividing DAC that divides the reference current in response to its input. The DAC also includes a current summer, such as a resistor, that receives the output current of each stage and provides the voltage that corresponds to the sum of the currents to a comparator. The comparator output controls a successive-approximation register.

Abstract: A disk drive for operating in an environment in which the drive is subject to physical shock includes a circuit which senses movement of a transducer head support arm which result from a shock's rotational component. The rotational shock is detected as a residual BEMF signal in the drive's VCM coil winding. The residual signal is extracted from much larger position control signals that are applied to the VCM winding during normal system operation by providing circuits that simulate the VCM winding voltage caused by the position control signal and subtracting the outputs of the simulation circuits from the actual VCM coil winding voltage. This eliminates the normal operating components and leaves a residual signal that represents only the small portion of the VCM BEMF signal that results from the rotational shock. A threshold circuit compares the shock BEMF signal to a predetermined threshold. If the BEMF signal exceeds the threshold, disk drive write operations are aborted.

Abstract: A disk drive comprises a pivot cartridge and a molded plastic actuator body. The cartridge includes a shaft and has an outer surface that is generally cylindrical and includes first and second ring-shaped portions and a necked-down portion separating the first and second ring-shaped portions. The body has a bore hole with an inner cylindrical surface that is deformable to expand from a first diameter to a second diameter. Each of the first and second ring-shaped portions has the second diameter and is disposed in an interference fit with the inner cylindrical surface.