Quasi-voltage sensing input impedance controlled preamplifier for magnetoresistive elements

摘要

A method and system for providing a voltage-sensing preamplifier for use with a magnetoresistive sensor is disclosed. The method includes providing a gain stage and providing a control circuit. The system includes the gain stage and the control circuit. The gain stage includes at least one input device that is coupled with the magnetoresistive sensor through an interconnect having a characteristic impedance. The at least one input device has a first input impedance. The control circuit provides at least one signal to the at least one input device. The at least one signal controls the first input impedance of the at least one input device to control a second input impedance of the voltage-sensing preamplifier, such that the preamplifier input impedance is modified toward the characteristic impedance of the interconnect to improve the bandwidth of the signal amplified by the system.