Stmicroelectronics Gmbh

Stmicroelectrontronics, Inc.

Kemal Ozanoglu

Baris Posat

Alessandro Venca

Roberto Alini

Roberto Allni

An amplifying circuit and method are disclosed for amplifying electrical signals, such as electrical signals generated by the read head of a disk drive. The circuit includes a pair of cross-coupled differential amplifier circuits. Each differential amplifier circuit is asymmetric, including two input transistors of different transistor types. For instance, a first of the two input transistors of each differential amplifier circuit may be a bipolar transistor and a second of the two input transistors may be a field effect transistor. By utilizing asymmetric differential amplifier circuits, a relatively wider operating frequency range is obtained.

Preamplifier circuit and method for a disk drive device

A preamplifier for correcting for thermal asperity transients in disk drives using magneto resistive read heads. The preamplifier has an input gain stage receiving a signal from the read head and an output buffer outputting a reader output to a read channel that is filtered of thermal asperity transients by a high pass filter positioned between the input gain stage and the output buffer. The high pass filter is voltage controlled based on an input control signal from a filter controller. The filter controller uses a low pass filter functioning as a peak detector to detect peaks in either the input or output voltage of the high pass filter. The low pass filter output is applied to a non-linear function generator generating the control signal for the high pass filter based on an increasing function of the absolute value of the low pass filter output.

Read head preamplifier with thermal asperity transient control

A circuit and method are disclosed for relatively rapidly causing the current flowing through a write head to transition between steady states without generating an appreciable amount of capacitively-coupled noise. Embodiments of the present invention generally provide drive voltage signals to the write head that have no common mode voltage levels during transitions between steady state current levels in the write head. In other words, the drive voltage signals applied to the write head are substantially entirely differential during write head current transitions. In an exemplary embodiment of the present invention, a driver circuit includes switching circuitry connected between the terminals of the write head and reference voltage supplies, such as positive and negative voltage supplies. The driver circuit further includes timing circuitry that generates control signals for controlling the switching circuitry.

Write head driver circuit and method for writing to a memory disk

A method and system are disclosed for generating descriptions of circuits representative of the behavior of dynamic systems. A state space model representing a dynamic system may be used to generate an electronic circuit equivalent having operating characteristics equivalent to the operating characteristics of the dynamic system. The electronic circuit equivalent may be then described as a SPICE circuit description which is simulated to determine the time and frequency domain characteristics of the dynamic system.

Growing community of inventors

Palo Alto, CA, United States of America

Kemal Ozanoglu