| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 360067000 | Specifics of the amplifier | 14 |
| 20090034112 | METHODS AND APPARATUS TO VARY INPUT IMPEDANCE OF A HARD DISK DRIVE READ PREAMPLIFIER - Methods and apparatus to vary the input impedance of a hard disk read preamplifier are disclosed. A disclosed method amplifies a read signal from a hard disk read head based on the impedance presented by the read head and changes the impedance presented to the read head based on the gain factor. | 02-05-2009 |
| 20090052079 | Magnetic head slider fabrication method, preamplifier and magnetic disk drive - Embodiments of the present invention set the resistance value and resistance change of a magnetoresistive element as the comparison criteria of a tester without use of an actual magnetic head slider in an inspection process during fabrication of magnetic head sliders. According to one embodiment, at the time of default setting of a tester, an emulator is connected to a preamplifier of a magnetic characteristic measurement device. Signals which are obtained by emulating the resistance value and resistance change of the magnetoresistive element are inputted to the preamplifier from the emulator. The resistance value and resistance change serve as references. The output of the preamplifier is A/D converted to be inputted to the MPU. In the MPU, the A/D converted output is converted into a resistance value to be stored in the ROM. The tester uses the resistance value stored in the ROM as a reference to compare the measured resistance value of the magnetoresistive element therewith. Since the set reference value changes with time, the emulator is connected to the tester regularly for checking and adjusting the reference value. | 02-26-2009 |
| 20090141388 | MAGNETIC DISK APPARATUS - A preamplifier receives a servo gate signal indicating whether magnetic information read out from a disk by a head is servo data for positioning-use or user data stored in a user area available for reading and writing of given data. In the preamplifier, a servo data gain and a user data gain are set in advance. Based on a received servo gate signal, the preamplifier changes the gain depending on whether the head outputs the servo data or the user data. | 06-04-2009 |
| 20090268332 | STORAGE DEVICE AND GAIN ADJUSTING DEVICE - An amplifier amplifies, according to a first gain value, a first input signal acquired by reproducing first information from first areas having the first information recorded therein area by area in order. The amplifier also amplifies, according to a second gain value, a second input signal acquired by reproducing second information pursuant to reproduction of the first information, from a second area adjacent to the first area and that has the second information recorded at a recording level different from that of the first information. When the first input signal is amplified, a first gain value following a change in the first signal is calculated so that the level of the amplified signal becomes constant. When the second input signal is amplified, a second gain value following a change in the first gain value is calculated so that the level of the amplified signal becomes constant. | 10-29-2009 |
| 20100110578 | SIGNAL AMPLIFIER AND STORAGE DEVICE - According to one embodiment, a signal amplifier amplifies a read signal read from a storage medium by a head, and includes an amplifier, a detector, and an impedance controller. The amplifier amplifies the read signal received from the head to obtain an amplified signal, and varies the input impedance of the read signal based on a control signal. The detector detects the frequency characteristic of the amplified signal output from the amplifier and determine the frequency characteristic as a first frequency characteristic. The impedance controller generates the control signal such that the first frequency characteristic detected by the detector becomes a predetermined second frequency characteristic. | 05-06-2010 |
| 20110002062 | ANALOG MULTIPLEXER CIRCUITS AND METHODS - A sample and hold circuit is disclosed that provides longer hold times. An analog multiplexer circuit is also disclosed that exhibits low switch leakage. The analog multiplexer circuit comprises a shared node, a plurality of input circuits, a control input for selecting one or more of the plurality of input circuits, and an amplifier coupled to the shared node. Each input circuit comprises an input node, a primary input switch for selectively coupling an input to the input node, and a secondary input switch for selectively coupling the input node to the shared node, wherein the secondary input switch comprises one or more transistor switches. The parasitic drain and source diodes of one or more transistor switches in secondary input switch in a selected input circuit are coupled to a voltage that is distinct from an input signal of the selected input circuit. For input circuits not selected, the parasitic drain and source diodes of secondary input switch transistor switches are coupled to an output of the amplifier. | 01-06-2011 |
| 20110102931 | HARD DISC DEVICE CONTROL CIRCUIT AND HARD DISC DEVICE - A head of a hard disc device is retracted to a predetermined position by operating a VCM (Voice Coil Motor) driver. Trouble in a hard disc is detected and retraction is performed even if a short circuit occurs in either of the output line of a VCM driver in an input end of a high potential side or in an input end of a low potential side. A ground short circuit is detected in each side separately and different retracting methods are executed for each case. | 05-05-2011 |
| 20110109984 | WRITING AND READING MULTI-LAYER CONTINUOUS MAGNETIC RECORDING MEDIA, WITH MORE THAN TWO RECORDING LAYERS - A method and apparatus for writing magnetization states in magnetic layers of a multi-layer continuous magnetic recording medium with more than two recording levels and a method and apparatus for reading readback pulse shapes representing a magnetization state transition between such written magnetization states. Writing each magnetization state includes selecting the magnetization state, determining a write current sufficient to write the magnetization state, and applying the write current to a magnetic write head to write the magnetization state, including simultaneously writing associated magnetic states in each magnetic layer of at least one pair of magnetic layers. A readback pulse shape representing a written magnetization state transition is read. The written magnetization state transition is uniquely identified from the readback pulse shape of the transition or from both the readback pulse shape of the transition and the readback pulse shape of one or more contiguous magnetization state transitions. | 05-12-2011 |
| 20150077879 | Disk Drive with Preamplifier for Multiple Readers in a Slider with a Common Return Signal - Disk drive embodiments with common lead connections in the slider, suspension, and preamplifier are described. The arm electronics IC includes a preamplifier with single-ended input from the set of signal traces that include a common signal return lead for the plurality of read transducers (readers) in the slider. Two embodiments of the preamps are described that include a single-ended design and a pseudo-single-ended design. Each embodiment supplies the required bias to each read transducer using an operational transconductance amplifier (OTA) that drives a variable current source connected to the transducer. The positive input to the OTA is a DC voltage with the AC signal from the transducer imposed on it. The negative input is a DC reference voltage. Various embodiments of the signal trace configuration on the suspension are described including a single and double layer embodiments. | 03-19-2015 |
| 360068000 | Recording amplifier | 5 |
| 20090190247 | Overshoot duration range selection in a hard disk drive - A hard disk drive that stores data on a disk. An overshoot duration is used to write data onto the disk. The value of the overshoot duration is a function of the data rate, which can vary for different areas of the disk. For example, the data rate can be higher at an outer diameter of the disk than at an inner disk diameter. The overshoot duration can therefore be different when writing data at the outer diameter than the duration used to write data at the inner diameter. The data rate can be determined by analyzing a preamble of the data written onto the disk. | 07-30-2009 |
| 20100061007 | STORAGE DEVICE AND CONTROL CIRCUIT - According to one embodiment, a storage device includes a rotary actuator, vibration detectors, an analog operation circuit, an analog-to-digital converter, and a rotation vibration compensation controller. The rotary actuator positions a head with respect to a storage medium to perform reading or writing. The vibration detectors are located substantially on both sides of the rotation center of the rotary actuator, detects rotation vibration component of a one-axis direction, and outputs a vibration detection signal. The analog operation circuit calculates a rotation vibration detection signal proportional to rotation vibration disturbance applied to the rotary actuator by differential amplification of the vibration detection signal. The analog-to-digital converter converts the rotation vibration detection signal into a digital signal and outputs rotation vibration detection data. The rotation vibration compensation controller controls the rotation vibration disturbance applied to the rotary actuator to be eliminated based on the rotation vibration detection data. | 03-11-2010 |
| 20100246048 | PREAMPLIFIER AND METHOD FOR SYNCHRONIZATION WITH BIT PATTERNED MEDIA - A preamplifier and method writes data synchronized with the passing of a write head in a magnetic storage device over bit islands in discrete patterned recording media. The preamplifier contains a write pre-driver that conditions write data, a synchronization circuit that accepts a delay offset value and a write clock and produces a delayed clock, and a write output driver that is gated by the delayed clock to produce write pulses for magnetizing the bit islands. Gating the write output driver using the delayed clock results in more accurate synchronization than delaying the write data into the preamplifier due to the reduction of the overall length and variability of interconnects and transistors in the intervening circuitry. Write clock generation circuitry, as well as bit position sensor circuitry for use with bit position signals produced by a read head or by a separate bit position sensor, are optionally integrated into the preamplifier, close to the write output driver and write head, for further improvements in delay accuracy and stability. Write pulses produced by the preamplifier are thus well aligned with the bit islands, resulting in higher magnetization and an improved bit error rate. | 09-30-2010 |
| 20130293982 | DISK DRIVE EMPLOYING SINGLE POLARITY SUPPLY VOLTAGE TO GENERATE WRITE CURRENT - A disk drive is disclosed comprising a disk, an actuator arm comprising a suspension, and a head coupled to a distal end of the suspension, wherein the head comprises a write coil. The disk drive further comprises a preamp operable to generate a write current applied to the write coil in response to a single polarity supply voltage which may be positive or negative. In one embodiment, the transmission lines that couple the write coil to the suspension comprise respective, parallel plate sections that form a capacitance which enables driving the preamp with the single polarity supply voltage. | 11-07-2013 |
| 20140063639 | PRE-AMPLIFIER OUTPUT STAGE WITH INTEGRATED TEST BUFFER - Disk drive pre-amplifier output stage circuitry is presented including a high pass input filter for removing DC offsets from differential read data signals and providing an input to AB drivers of the output stage, in which an offset test circuit selectively drives the high pass filter output nodes according to the offset at the filter input to facilitate measurement of the preceding circuit offset at the driver output terminals, and a common mode regulator circuit regulates common mode voltages at the first and second driver output nodes to a predetermined value in read and write modes. | 03-06-2014 |
