Lsi Corporation

Avago Technologies General IP (singapore) Pte. Ltd.

Avago Technologies International Sales Pte. Limited

Robert Alan Greene

George Mathew

Hongwei Song

Yuan Xing Lee

Angelo Rocco Mastrocola

Suharli Tedja

Jacob K Easter

A system includes a first transistor having a drain and source connected between a supply voltage and an output of a voltage regulator. A gate of the first transistor receives a first gate voltage. The system includes a second transistor having a drain and source connected between the supply voltage and the drain of the first transistor. The second transistor protects the first transistor from excessive voltage. The system includes a level shifter connected between a gate of the second transistor and a gate of the first transistor. The level shifter produces a level-shifted gate voltage for the second transistor that is based on the first gate voltage and that is proportional to an output load current output at the source of the first transistor.

Devices and methods for dynamic overvoltage protection in regulators

An apparatus for storing data includes a storage medium, a head assembly disposed in relation to the storage medium and operable to read and write data on the storage medium, an analog high pass filter operable to filter an output from the head assembly to yield a filtered analog signal, wherein a high pass corner frequency of the analog high pass filter is below a servo data frequency in the data, an analog to digital converter operable to sample the filtered analog signal to yield digital samples, and a digital filter operable to perform pole-zero compensation for the analog high pass filter on the digital samples to yield filtered digital samples, with a zero at the high pass corner frequency of the analog high pass filter, and with a pole at a frequency higher than the high pass corner frequency of the analog high pass filter.

Servo channel hybrid analog-digital high pass filter

A magnetic recording system includes an array of analog inputs operable to receive analog signals retrieved from a magnetic storage medium, a quadrature amplitude modulator operable to combine the analog signals to yield a quadrature amplitude modulated signal, a quadrature amplitude demodulator operable to yield a plurality of demodulated signals from the quadrature amplitude modulated signal corresponding to each channel of the array, and a joint equalizer operable to filter the plurality of demodulated signals to yield an equalized output.

Array-reader based magnetic recording systems with quadrature amplitude modulation

Described embodiments provide an interleaved sampler having N sample and hold circuits for sampling an input signal, and M multiplexers. Each multiplexer is adapted to couple all N of the plurality of sample and hold circuits to a respective output of the interleaved sampler. The interleaved sampler samples at a sample rate of f, has an interleaved sampling period of M/f, where M is greater than one and less than N. Because there are more sample and hold circuits than there are samples taken during an interleaved sampling period, different combinations of the sample and hold circuits are used from interleaved sample period to interleaved sample period. This reduces spurious tones generated from offset voltages when using interleaved sample and hold circuits. The order of the sample and hold circuits are clocked might be random, pseudorandom, or a fixed pattern longer than the interleaved sampling period.

Offset-induced signal cancellation in an interleaved sampling system

Various embodiments of the present invention provide systems and methods for servo data based harmonics calculation. For example, a method for calculating harmonics is disclosed that includes: providing a data processing circuit; receiving a first data set derived from a data source during a servo data processing period; performing a first harmonics calculation using the first data set to yield a first harmonics ratio; receiving a second data set derived from a source other than the previously mentioned data source during a user data processing period; performing a second harmonics calculation using the second data set to yield a second harmonics ratio; and calculating a ratio of the first harmonics ratio to the second harmonics ratio.

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Fort Collins, CO, United States of America

Robert Alan Greene