Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

Abstract: A disk drive controller including a differential voice coil motor control function is disclosed. The differential voice coil motor control function includes an on-chip compensation network for the inner control loop, including a resistor formed of one or more MOS transistors connected in series. The gate of the MOS transistors in the compensation network is driven with a bias voltage based on a tuning current, where the tuning current is derived so that it varies with process and temperature variations of the integrated circuit, for example with variations in an on-chip capacitor. The on-chip compensation network can be tuned with sufficient precision to properly compensate the inner control loop to provide the desired frequency response in driving the voice coil motor in the disk drive.

Abstract: A disk drive controller including a differential voice coil motor control function is disclosed. The differential voice coil motor control function includes an on-chip compensation network for the inner control loop, including a resistor formed of one or more MOS transistors connected in series. The gate of the MOS transistors in the compensation network is driven with a bias voltage based on a tuning current, where the tuning current is derived so that it varies with process and temperature variations of the integrated circuit, for example with variations in an on-chip capacitor. The on-chip compensation network can be tuned with sufficient precision to properly compensate the inner control loop to provide the desired frequency response in driving the voice coil motor in the disk drive.

Abstract: The present invention relates to a hard disk drive system having overvoltage protection circuits for various types of overvoltage conditions. For example, the system comprises one or more hard disk drive integrated circuit chips residing on a board and a hard disk drive power plug receptacle residing on the board having two different value power supply ports associated therewith. The receptacle is operable to receive a power plug therein, wherein when the power plug is inserted therein in a proper orientation the two different value voltages are properly supplied to the one or more hard disk drive integrated circuit chips, and wherein when the power plug is inserted therein in an improper orientation the two different value voltages are switched with respect to their intended values. The system comprises a reverse power plug orientation protection circuit coupled between the hard disk drive power plug receptacle and at least one of the one or more hard disk drive integrated circuit chips.

Abstract: The present invention relates to a hard disk drive system having overvoltage protection circuits for various types of overvoltage conditions. For example, the system includes one or more hard disk drive integrated circuit chips residing on a board and a hard disk drive power plug receptacle residing on the board having two different value power supply ports associated therewith. The receptacle is operable to receive a power plug therein, wherein when the power plug is inserted therein in a proper orientation the two different value voltages are properly supplied to the one or more hard disk drive integrated circuit chips, and wherein when the power plug is inserted therein in an improper orientation the two different value voltages are switched with respect to their intended values.

Abstract: The present invention provides an improved model and methodology for simulating motor performance which allow increased control accuracy at the higher currents, higher speeds, and/or higher current change rates required in modem mass storage devices. In addition, the invention provides methods for simulating motor performance, and for testing a motor commutation scheme. The model includes a plurality of phases extending between first ends joined at a center tap and second ends extending outward from the center tap to a corresponding plurality of phase taps, and a mutual inductance component disposed between two of the phases, wherein the mutual inductance and/or the phase inductance components may be a function of rotor position and/or current.

Abstract: The invention includes a method and apparatus for detecting the position of an electric motor rotor by sensing the zero crossing or polarity change of a mutual inductance associated with the motor. The use of mutual inductance provides for consistent position detection unaffected by motor speed or winding current, thus providing significant advantages over traditional back emf zero crossing detection methods. The mutual inductance zero crossing may be detected by measuring a voltage signal in a floating phase of the motor, filtering back emf and excitation components out of the measured voltage signal, and detecting a polarity change or zero crossing in the resulting mutual inductance signal.

Abstract: An apparatus for controlling an actuator in response to a target speed voltage signal, the actuator having a moveable member and having a coil that influences movement of the member. A first summing node is provided having a control output voltage, for summing or subtracting voltages applied thereto, as the case may be and receiving the target speed voltage signal at a first, summing input thereto. A proportional compensation unit is provided, receiving the control output voltage and providing as an output a proportionally compensated output signal. An integral compensation unit is provided, receiving the control output voltage and providing as an output an integrally compensated output signal. An inverse compensation unit is provided, receiving the target speed voltage signal as an input and providing an inversely compensated output signal having a voltage corresponding to the voltage of the target speed voltage signal multiplied by the inverse of a predetermined amplification factor.

Abstract: In a multichannel recording/playback apparatus, a bi-directional transport longitudinally moves a magnetic tape past a multitransducer magnetic head for recording and/or playback. The magnetic head is positionable to selected tracks in a stepwise manner across the width of the tape. A head positioning servo utilizes binary patterns pre-recorded on the tape, consisting of magnetized blocks and non magnetized blocks which are read by a servo transducer integral with the multitransducer head stack. For each centerline corresponding to a specified track location, the servo tranducer straddles the line between adjacent, longitudinally recorded patterns and when the servo transducer is "on track" two conditions are met: 1) the played back code is the track address included in the track location identifier stored in a controlling microcontroller, 2) the amplitudes of the "1 bits" of the played back code are all the same and equal to 1/2 the amplitude of a full track width output.

Abstract: In a capstanless tape transport, practice of the invention provides substantially constant tape tension when tape is spooled from a supply reel to a take up reel over the tape's entire length, for either direction of tape travel. The tape velocity is maintained constant by a closed loop velocity servo controlling the current applied to one of the reeling motors, and the tape tension is maintained substantially uniform by applying a current derived in an open loop manner to the other motor, such that the sum of the currents to the two reeling motors equals a constant.The invention may be implemented either utilizing analog control or digital control of the reeling apparatus.