Patent ID: 6175462
Filing Date: 2001-01-16
Classification: G11B,H03F

Abstract:
A preamplifier circuit for a magnetoresistive (MR) element in a disk storage system comprising:a biasing circuit for providing bias to said MR element which comprises a voltage bias feedback loop which senses a differential between DC voltage across the MR element and a reference voltage and the voltage bias feedback loop further comprising an amplifier which amplifies the differential and a transconductance amplifier which feeds current into the MR element in response to the amplifier;an offset control feedback loop independent of the biasing circuit; anda single-ended, high input impedance amplifying circuit connected to the MR element in parallel with the biasing circuit and which provides an output signal to said offset control feedback loop which provides an offset control input signal to the amplifying circuit which is independent of the baising circuit.