Agere Systems Inc.

Lsi Corporation

Avago Technologies International Sales Pte. Limited

Scott M O'Brien

John D Leighton

Cameron Carroll Rabe

Jeffrey A Gleason

Michael Straub

Michael John O'Brien

Nameeta Krenz

Carl F Elliott

Robert Wimmer

Arvind Reddy Aemireddy

Jason P Brenden

Yan Li

David W Kelly

Peter John Windler

Hao Fang

David Fitzgerald

James Patrick Howley

Joseph D Stenger

Ronen Malka

Xuemin Yang

Gregory W Starr

Shubha Bommalingaiahnapallya

A solution can detect an HDD laser mode hop within an improved response time using a sensor amplification circuitry balanced by a frequency response of a gain stage circuit. A sensor of a first circuit can receive an optical signal of a laser as input and output a first voltage that an amplifier can amplify to produce an amplified first voltage indicative of a mode hop event trailing the optical signal by a first response time of a first frequency response. A second circuit coupled in series with the first circuit and operating according to a second frequency response an inverse of the first frequency response can receive the amplified first voltage and generate, based at least on the amplified first voltage adjusted by the second frequency response, a second voltage indicative of the mode hop event within a second response time that is shorter than the first response time.

Systems for and methods for fast mode hop detection and correction for hard disk drive recording systems

A memory system, sensor circuit, and method of operating a memory system are provided. The disclosed memory system includes a first transducer configured to output a first electrical signal indicative of a first operating parameter of the memory system. The memory system is further disclosed to include a second transducer configured to output a second electrical signal indicative of a second operating parameter of the memory system where the second transducer shares a node with the first transducer. The memory system is further disclosed to include a sense amplifier that receives the first electrical signal and the second electrical signal and provide an output responsive to both the first electrical signal and the second electrical signal to a preamplifier Integrated Circuit (IC).

Sensor circuit supporting multiple transducers with dedicated and shared terminals

The present inventions are related to systems and methods for data processing, and more particularly to systems and methods for synchronizing operations in a data storage system.

Systems and methods for timing control in a data processing system

A fly height control circuit includes an input node to receive a digital control signal, an output node to output a control current to a resistive heater element to adjust a spacing between a read/write head and a surface of a storage medium, and control circuitry to process the digital control signal and generate the output control current based on the digital control signal. The control circuitry generates a first reference current based at least in part on the control current output from the output node. The control circuitry controls a slew rate of the first reference current to generate a slew rate controlled reference current. The control circuitry generates a second reference current based on a feedback voltage at the output node. The control circuitry compares the slew rate controlled reference current with the second reference current to adjust the control current output from the output node.

Fly height control for hard disk drives

A recording system employing a magneto-resistive (MR) element senses a resistance value of the MR element and generates one or more MR resistance (MRR) signal values based on the sensed MR element resistance value. The MRR signal values might be, for example, current or voltage values proportional or inversely proportional to the MR element resistance value. The MRR signal values might be employed to control one or more of: i) a unity gain bandwidth of a bias loop for the MR element, ii) an MR read head preamplifier low corner frequency, and iii) a slew rate across the MR element.

Magneto-resistive head resistance sensor

An apparatus and method for determining a resistance of a magneto-resistive head. A current drawn by the head, in response to a fixed bias voltage across the head, is converted to a zero temperature coefficient current such that when supplied to a resistor connected to an input terminal of a comparator the effects of variations in the resistance value are avoided. An output signal of the comparator indicates the resistance of the magneto-resistive head.

Resistance mode comparator for determining head resistance

A method and apparatus for detecting signal peaks caused by a thermal asperity event in a magnetic recording media to reduce data reading errors introduced by the thermal asperity event. A common mode voltage is determined for differential signals representing data bits read from the magnetic recording media and a threshold voltage produced responsive to the common mode voltage. A comparator determines if either of the differential signals exceeds the threshold voltage, thereby indicating the occurrence of a thermal asperity event.

Variable threshold bipolar signal peak detector

A preamplifier circuit is connected to a transducing head, and has integrated bias circuitry and offset recovery circuitry. The offset recovery circuitry is activated in response to a transition from write mode to read more to provide an output signal representative of a signal across the transducing head. The bias circuitry is driven by the output signal of the offset recovery circuitry to bias the transducing head.

Integrated bias and offset recovery amplifier

A pre-amplifier, a Thevenin writer and a disk drive employing transistors having a breakdown voltage below a circuitry operating voltage. In one embodiment, the pre-amplifier includes an emitter-follower transistor pair couplable to a power supply and a differential transistor pair, having a collector-emitter breakdown voltage below a voltage of the power supply, that receives current from, and controlled by, the emitter-follower transistor pair.

Pre-amplifier employing transistors having a diminished breakdown voltage and a disk drive and a Thevenin writer employing the same

A write driver circuit selectively provides a write current through a write head in first and second opposite directions. The write driver circuit is connected to the write head through an interconnect. The write driver circuit provides an incident write current signal through the interconnect to the write head, and also provides a reflection cancellation signal through the interconnect to the write head. In an exemplary embodiment, the incident write current signal is provided by providing an incident voltage signal across the write head, and the reflection cancellation signal is provided by providing a reflection cancellation voltage signal across the write head. In an exemplary embodiment, the reflection cancellation signal is a delayed and filtered version of the incident write current signal that cancels a reflected signal that is reflected at the interface between the interconnect and the write head due to impedance mismatching.

Disk drive writer with active reflection cancellation

A write driver circuit selectively provides write current through a write head in first and second opposite directions. First and second active devices are driven with first and second pre-drive signals. Third and fourth active devices are driven with third and fourth pre-drive signals. First and second pull-up resistances are provided respectively between the first and second active devices and a fixed voltage, and third and fourth pull-up resistances are provided respectively between the third and fourth active devices and the fixed voltage. A first capacitor is connected between the first active device and an intermediate point of the third pull-up resistance, and a second capacitor is connected between the second active device and an intermediate point of the fourth pull-up resistance.

Growing community of inventors

Eagan, MN, United States of America

Scott M O'Brien