MAGNETIC ENCODER WITH TUNNEL MAGNETORESISTANCE EFFECT

摘要

A magnetic encoder with tunnel magnetoresistance (TMR) effect comprising a magnet (11), a magnetic sensitive element, at least two operational amplifiers (17), a digital signal processing chip (18), and an output display module (19). The magnetic sensitive element uses a TMR biaxial magnetic field chip (15) located below the magnet (11). The operational amplifier (17), the digital signal processing chip (18), and the output display module (19) are arranged on a PCB circuit board (16), the PCB (16) is arranged on the outside of the magnet (11) and the TMR biaxial magnetic field chip (15). Another magnetic encoder with TMR effect comprises a magnetic drum (51), a magnetic grid (52) on the edge of the magnetic drum (51), a magnetic sensitive element, a signal amplifying and shaping module (54), a counting module (55), a computing and processing module (56), and a display module (57). The magnetic sensitive element uses a TMR half-bridge chip (53), the TMR half-bridge chip (53) is arranged on the edge of the magnetic drum (51) and 1-5 mm away from the magnetic grid (52). The signal amplifying and shaping module (54), the counting module (55), and the computing and processing module (56) are arranged on a PCB circuit board (58), the PCB circuit board (58) is arranged on the outside of the magnetic drum (51) and the TMR half-bridge chip (53). Using TMR chips made of TMR material as the magnetic sensitive element enables the magnetic encoder of the present invention to have high sensitivity, optimal temperature stability, high signal to noise ratio, and good noise resistance performance.