A CMOS Closed Loop AMR Sensor Architecture
Georgakopoulos Ioannis
Abstract
This work presents the analysis and design of a fully analog, closed loop, signal conditioningcircuit for the readout of Anisotropic Magneto-Resistance magnetic sensors. The architectureis based on a fully differential design, consisting of an instrumentation amplifier with choppingto achieve low output noise, followed by a transconductor. The output current of the transcon-ductor is directly fed back to the sensor, through a dedicated on-chip inductor for magnetic fieldoffsetting purposes, closing this way a negative feedback loop. The proposed design has beenimplemented and simulated in TSMC 180nm 5V CMOS process.