Patent ID: 6172548
Filing Date: 2001-01-09
Classification: G11B,H03F

Abstract:
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; andlogic 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 potential which appears on said differential AC voltage signal when said current generator is first turned on.