Matsushita Electric Industrial Co., Ltd.

Maxtor Corporation

Panasonic Corporation

Kabushiki Kaisha Toshiba

Richard Oswald

Tamotsu Yamamoto

Takashi Ryu

Erhard Theodor Schreck

Takuya Ishii

Thao Anh Nguyen

Brian D Strom

Mikio Motomori

Duc H Banh

Scott A Hughes

Kazuhiro Saito

Chris Hawks

Tim Glassburn

Li Zhang

Michael L Mallary

Takeshi Tanaka

Hiroshi Saito

Lin Guo

Don Brunnett

Gabor Szita

Wei Guo

Donald Joseph Brunnett

Wentao Yan

Hiroki Akashi

Bruce C Schardt

Hirohisa Tanabe

Jingbo Yu

Andrew LeFebvre

Masaaki Koto

Joerg Ferber

Anthony R Hurtado

Hideki Shirokoshi

Tony Hurtado

Takuya Ishi

A method of writing servo spirals for spiral-based self-servo writing includes determining control parameters for controlling movement of a write head between a first and a second disk radial location at a first velocity, writing a first spiral while controlling the movement of the write head between the first and the second disk radial location at the first velocity according to the determined control parameters, writing a second spiral while controlling movement of the write head between the first and the second disk radial location at a second velocity that is different from the first velocity, based on timing and location information from the first spiral, and writing a third spiral while controlling movement of the write head between the first and the second disk radial location at the first velocity according to the determined control parameters and based on timing and location information from the second spiral.

Calibration spiral to improve guide spiral placement

A buck-boost switching regulator which includes a first switch, a first diode, an inductor, a second switch, a second diode, and a controller for controlling the first switch and the second switch, the controller being configured to receive a current signal indicative of a inductor current flowing in the inductor, and generating a signal indicative of an average current flowing in the inductor, the average current being utilized to control the first switch and the second switch, wherein the controller includes a first compensator circuit for outputting a voltage error signal, a second compensator circuit for outputting a current error signal and a modulator circuit to output a first control signal to control the first switch and a second control switch to control the second switch.

Buck-boost switching regulator

A switching regulator circuit including a high-side switch and a low-side switch; an inductor having a first terminal coupled to a common terminal between the high-side switch and the low-side switch, and a second terminal coupled to an output terminal of the switching regulator circuit; a low-pass filter coupled to the first terminal of the inductor, where the low-pass filter is operative for generating a ramp signal based on the voltage signal present at the first terminal of the inductor; and a hysteretic comparator coupled to the low pass filter, where the hysteretic comparator receives the ramp signal as an input signal, and generates an output signal which is operative for controlling the operation of the high-side switch and the low-side switch.

Hysteretic switching regulator

A frequency compensation circuit internal to an integrated circuit which comprises a transconductance amplifier having a first input configured to receive a reference voltage, a second input configured to receive an input voltage and an input current, a first output configured to output a first output current and a second output configured to output a second output current; and a compensation circuit connected to said second output of said transconductance amplifier, wherein said first output is connected to said second input.

Internal frequency compensation circuit for integrated circuit controllers

A control source and drivers for a thermal actuator fly height controlled heads in a disk drive system includes provisions for driving a heater element to dissipate various levels of power, and thus actuate the head by a desired amount, depending on whether the head is in a write mode or a read mode. Further, overshoot and undershoot are achieved as desired by providing initial values and equilibrium values and through the use of a control capacitor to provide a time constant to the drive signal to the heater element.

Method of operating read and write transducers by controlling thermal actuation

A method for monitoring the operability of a slider of a disk drive includes the steps of providing a slider that includes a read/write head that magnetically interacts with a storage disk, and a slider mover that adjusts a head-to-disk spacing, controlling an electrical stimulus to the slider mover with a drive circuitry, measuring an actual electrical response from the slider mover with the drive circuitry, and comparing the actual electrical response to an expected electrical response to determine an operability status of the slider mover. Further, changes in the actual electrical response can be monitored and used to predict future failure of the slider mover.

Method of detecting changes in operability status of a slider mover in a disk drive

A disk drive includes a drive housing, a storage disk, a slider and a drive circuitry. The slider magnetically interacts with the storage disk, and includes a read/write head that is positioned to have an actual head-to-disk spacing greater than zero nanometers during rotation of the storage disk. The drive circuitry can determine and/or monitor the actual head-to-disk spacing at any time during the operation of the disk drive based on an amplitude or a change in the amplitude of a signal such as a variable gain amplifier signal. In one embodiment, the slider includes a slider mover that receives current via the drive circuitry and causes a deformation of a portion of the slider to change the head-to-disk spacing based on the amplitude of the signal. In another embodiment, the read/write head moves during substantially consistent rotational velocity of the storage disk from a first actual head-to-disk spacing equal to approximately zero nanometers, to a second actual head-to-disk spacing that is greater than zero nanometers based on a desired amplitude of the signal.

System for monitoring and dynamically adjusting head-to-disk spacing in a disk drive

A regulating apparatus having an output node and being operative for regulating the voltage level at the output node in response to a reference signal provided as an input to the regulating apparatus. The regulating apparatus includes a linear amplifier stage operative for receiving the reference signal and being capable of sourcing current to the output node when the reference signal indicates that a present voltage level at the output node is less than a desired voltage level at the output node. The regulating apparatus also includes a switching regulator, which is controlled by the linear amplifier stage, and which is operative for sourcing current to the output node when the amount of current being sourced to the output node by the linear amplifier stage exceeds a predetermined threshold.

High efficiency, high slew rate switching regulator/amplifier

A current sensing circuit for use in a switching regulator having a high-side switch. The current sensing circuit includes a first sensing circuit coupled to the high-side switch for measuring current flowing in a positive direction through the high-side switch. The first sensing circuit includes a first replica device for generating a current which is a scaled version of the positive current flowing through the high-side switch. The current sensing circuit further includes a second sensing circuit coupled to the high-side switch for measuring current flowing in a negative direction through the high-side switch. The second sensing circuit includes a second replica device for generating a current which is a scaled version of the negative current flowing through the high-side switch.

Method and apparatus for performing lossless sensing and negative inductor currents in a high side switch

A method of regulating an output voltage by utilizing a switching regulator, where the switching regulator includes a high side switch, a low side switch having an active diode, a controller coupled to the high side switch and the low side switch, and a current measuring circuit coupled to the high side switch. The method includes the steps of: measuring the output voltage and if the output voltage is below a desired level, activating the high side switch so as to provide current to a load capacitor via a load inductor, if the voltage is above the desired level, activating the low side switch so as to sink current from the load capacitor via the load inductor; and utilizing the current measuring circuit to measure the current flowing through the high side switch in either a positive direction or a negative direction, where the controller is operable for controlling the current measuring circuit and disabling active components contained in the current measuring circuit and the active diode when the active components are not utilized during operation of the switching regulator so as to reduce operational power requirements of the switching regulator.

Performance controller for a step down current mode switching regulator

A power supply switching regulator including a common terminal; an input terminal for supplying a direct current input; an output terminal; a recirculating diode having a first terminal connected to the common terminal; an inductor having a first terminal connected to a second terminal of the recirculation diode and a second terminal connected to the output terminal; a capacitor having a first terminal connected to the output terminal and a second terminal connected to the common terminal; a switch connected between the input terminal and the first terminal of the inductor, the switch operable for switching between an ON state in which the direct current input is coupled to the inductor, and an OFF state in which the direct current input is isolated from the inductor; and a controller coupled to the switch and operable for controlling the amount of time the switch is in the ON state and the OFF state such that the duration of time the switch is in the ON state is inversely proportional to the difference between the voltage at the input terminal and the voltage at the output terminal.

Current mode switching regulator with predetermined on time

An active diode including a NMOS transistor having a source terminal, a drain terminal, a gate terminal and a back gate terminal, where the source terminal is connected to the back gate terminal and forms the anode terminal of the active diode, and the drain terminal forms the cathode terminal of the active diode. The active diode further includes an offset bias voltage source having a first terminal and a second terminal; and an amplifier having a non-inverting input terminal and an inverting input terminal, and an output terminal, where the inverting input terminal is connected to the drain terminal of the transistor, the non-inverting input terminal is connected to the first terminal of the offset bias source, the output terminal is connected to the gate terminal of the transistor, and the second terminal of the offset bias source is connected to the source terminal of the transistor.

Active diode

A switching regulator circuit with improved slope compensation for providing a regulated voltage to a load. The regulator circuit includes a power source and a switch circuit configured to control the coupling of the power source to the load. The operation of the switch circuit is controlled by a control signal generated by a control circuit. A feedback circuit is provided for generating a feedback signal indicative of the regulated voltage provided by the switching regulator circuit to the load. A circuit is provided to generate a sensed signal indicative of the current supplied by the power source. The regulator circuit further includes a timing signal generator for generating a timing signal, a ramp signal generator for generating a ramp signal, and a current source controlled by the ramp signal for generating a compensation signal indicative of the ramp signal. The control circuit generates the control signal based on the compensation signal, the timing signal, the sensed signal and the feedback signal.

Switching regulator with advanced slope compensation

A method of generating a slope compensation signal for use in a current mode switching regulator. The method includes the steps of summing a clock signal and a reference signal so as to generate a linear ramp signal; generating a non-linear signal from the linear ramp signal; multiplying a correction signal with an input voltage signal so as to generate a signal which varies based on a measured value of a current flowing within the current mode switching regulator; summing a first voltage signal corresponding to the non-linear correction signal and a second voltage signal indicating the difference between an actual voltage level of the current mode switching regulator and the desired voltage level of the current mode switching regulator so as to generate a first output signal which represents the second voltage signal minus the first voltage signal; and comparing the first output signal and the measured value of a current flowing within the current mode switching regulator, and generating a second output signal utilized to control current flow within the current mode switching regulator based on the result of the comparison.

Higher order slope compensation for fixed frequency current mode switching regulators

A displacement system for a hard disk drive comprising a driving circuit and first and second displacement elements. The driving circuit generates a driving signal from a source voltage level, a control signal, and a reference voltage level. The driving signal is applied across the first displacement element with respect to the reference voltage level. The driving signal is applied across the second displacement element with respect to the source voltage level.

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San Jose, CA, United States of America

Richard Oswald