Agere Systems Inc.

Arvind Reddy Aemireddy

Jeffrey A Gleason

Scott M O'Brien

Cameron Carroll Rabe

Michael Straub

Robert Wimmer

Ronen Malka

Nameeta Krenz

Shubha Bommalingaiahnapallya

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 differential input/differential output converter circuit. The circuit comprises differential complementary input modules each comprising cross-coupled devices for biasing current mirror masters to a condition that increases the operating speed in response to a transition in the differential input signals. Certain current mirror masters are biased to a strong threshold condition and other current mirror masters are biased to a weak threshold condition responsive to a state of the differential input signals. According to another embodiment, the converter circuit further comprises a boost circuit capacitively coupled to the converter circuit for providing further speed improvements.

Differential input/differential output converter circuit

The invention is a dual stage power supply with a protection circuit for preventing reverse conduction through the lower voltage driver of the dual stage power supply and excess power dissipation when the higher voltage driver is on. In one embodiment of the invention, the protection scheme comprises a comparator that detects when the voltage on the output pad exceeds a predetermined voltage and a protection transistor which is controlled by the comparator to block reverse conduction through the lower voltage driver when the higher voltage driver is operating.

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Inver Grove Heights, MN, United States of America

Arvind Reddy Aemireddy