HIGH-SENSITIVITY SINGLE-CHIP PUSH-PULL TYPE TMR MAGNETIC FIELD SENSOR

摘要

A high-sensitivity single-chip push-pull type TMR magnetic field sensor (30) comprises a substrate (31) and two comb-shaped soft magnetic flux concentrators (36, 37) located on the substrate (31) and forming an interdigital structure. The comb-shaped soft magnetic flux concentrators (36, 37) respectively comprise N and N-1 rectangular comb teeth and corresponding comb seats, N being an integer greater than 1. Gaps are formed between comb teeth of one comb-shaped soft magnetic flux concentrator (36) and the comb seat of the other comb-shaped soft magnetic flux concentrator (37) in an X direction. Adjacent comb teeth form odd space gaps marked as 2m-1 and even space gaps marked as 2m in a +Y direction, m being an integer and 0mN. Push magnetic resistor sensing unit series (38) and pull magnetic resistor sensing unit series (39) are located in the odd space gaps and the even space gaps respectively, and electrically connected into a push-pull type magnetic resistor sensing unit electrical bridge. Magnetization directions of magnetic resistor sensing unit magnetic pinning layers are a Y direction. A magnetic field gain efficient ANS between an external magnetic field B_(x-ext) in the X direction and a B_y magnetic-field component at the space gaps in the Y direction is equal to B_y/B_(x-ext) and is greater than 1. The magnetic field sensor (30) is advantageous in simple structure, high sensitivity, and low power consumption.