Improved pulse carrier MI effect by flash anneal of amorphous wires and FM wireless CMOS IC torque sensor

Abstract

A figure of merit (FOM) for the magneto-impedance (MI) effect is defined by the product of the MI ratio and the cut-off frequency for ac field detection as ( Hex 0 ) cuto . The FOM for almost zero-magnetostrictive amorphous wire of 30 m diameter was about improved 2.5 times by twisting and flash annealing using a pulse current of 80 mA, 1 second. A sensitive, quick response, and low power consumption wireless FM type MI sensor is constituted using the high FOM amorphous wire head combined with all CMOS IC sensor circuit. The wireless MI sensor is successfully applied to a torque sensor fixed on an automobile power steering steel.

Advanced Magnetic Microwires as Sensing Elements for LC-Resonant-Type Magnetoimpedance Sensors: A Comprehensive Review

“…Some prototype sensors employing these materials as sensing elements, i.e., magnetic field sensors [46][47][48][49][50], current sensors [51,52], position sensors [53,54], stress sensors [55,56], torque sensor [57], biosensors [58][59][60][61][62][63], were proposed and successfully developed. The current progress of GMI is thrusted toward the increase of magnetic-field sensitivity and the optimization of the signal-to-noise ratio in the GMI sensor devices [64,65].…”

A Feasibility Study of a Noncontact Torque Sensor with Multiple Hall Sensors

“…The elastomagnetic effect of ferromagnetic materials exhibits the phenomenon that strain or stress induced by the torque on the shaft can change the magnetic properties of a magnetostrictive material and cause hysteresis deformation and permeability [5]. A frequency modulation-(FM-) type wireless CMOS IC magnetoimpedance (MI) sensor is constructed using flashannealed amorphous wire [6]. A number of resonant wireless surface acoustic wave (SAW) sensors have been developed for measuring temperature, pressure, and torque in various automotive applications [7].…”

Magnetic sensor based on giant magnetoimpedance effect

“…Due to the highly sensitivity of the GMI materials, lots of effort has been paid on this effect for sensor applications, such as magnetic field [7]- [13], current [14]- [18], stress [19]. In the formerly research, most of the GMI magnetic sensors adopt that complicated and elaborate coils winding around the GMI probes to supply a bias magnetic field for the amorphous materials to fix the working point [7]- [12], which bring excess power consumption.…”