Appeal No. 1997-3973
Application No. 08/366,561
The disclosed invention relates to an integrated circuit
for interfacing to a disk drive having at least one
magnetoresistive sensing element. The disclosed invention
also relates to a method for sensing voltages from the
magnetoresistive sensing element.
Claims 1 and 19 are illustrative of the claimed
invention, and they read as follows:
1. An integrated circuit for interfacing to a disk
drive having at least one magnetoresistive sensing
element, comprising:
a current generator connected to drive a bias
current across said magnetoresistive sensing element;
connections for transferring the AC voltage on
said magnetoresistive sensing element through one or more
coupling capacitors, to provide a differential AC voltage
signal;
a preamplifier connected to receive and amplify said
differential AC voltage signal;
a shorting switch connected to selectably short
out said differential voltage signal at the inputs to
said preamplifier; and
logic connected to activate said shorting switch for
a limited time when said current generator turns on, said
logic consisting of a one-shot connected to be activated
by transitions, on a read/write mode-select line, from a
state which indicates write mode to a state which
indicates read mode;
whereby said shorting switch discharges the DC
2
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