Agere Systems Guardian Corp.

Vtc Inc.

Jeremy R Kuehlwein

Craig Matthew Brannon

John J Price, Jr

A magnetic recording control circuit for controlling current through a magnetic recording head includes a switch network, a signal coupler, and a current reducer. The switch network is connected to first and second magnetic recording head node regions and includes first, second, third, and fourth switches each having a variable magnitude conduction path and a control region. The signal coupler includes an input region and a plurality of output regions each connected to the control region of a corresponding switch. The current reducer is connected to the first magnetic recording head node region and shunts current away from the signal coupler.

Magnetic recording control circuit with current reducers

A write driver, having a pair of head pins for connection to a write head, includes two push-pull buffer circuits connected respectively between first and second pull-up resistors and the control nodes of first and second upper drive transistors. The buffer circuits selectively charge and discharge the inherent capacitances of the upper drive transistors, thereby accelerating their turn on and turn off without diminishing head swing. Moreover, connecting the buffer circuits between the pull-up resistors and the upper transistors effectively isolates, or buffers, the pull-up resistors from the self-inductance voltages of the write head, reducing glitching in the write-head output signal.

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Woodbury, MN, United States of America

Jeremy R Kuehlwein