Design and Analysis of miniature low power CMOS-MEMS fluxgate magnetic sensor

• Main Authors: Guan-Yu-Long, 龍冠宇
• Other Authors: 鄭振宗
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/dn585r

碩士 === 國立臺北科技大學 === 機電科技研究所 === 105 === This paper explores the low power design parameters of the planer microfluxgate vector magnetic sensor. The planer excition coil and induction coil were implemented on a 1 mm ×1 mm CMOS MEMS chip of 0.18 μm process provided by the Chip Implementation Center (CIC). The 1 μm-thick magnetic cores were made by photolithography and magnetron sputter process. Two fluxgate sensors of different core width and core length were fabricated and tested under various excitation currents of different amplitude and frequency to probe the field sensing capability. The experimental results show that sensor of 60 μm core width exhibits maximum sensitivities of 0.172 V/T and 0.149 V/T for x- and y- axis, respectively, under the excition current at 400 kHz and 37 mArms. The excitation power for maximum sensitivity is 0.629 W, which is only half the value for a larger chip previously reported by our group. The result shows that power consumption can be reduced by shrinking the size of the sensor. For the sensor with a longer core, the sensitivities are respectively 0.139 V/T and 0.128 V/T for x- and y- axis, which implies that further optimization of sensitivity can be achieved by changing the core length. The experimental results are expected to contribute to the future development of high sensitivity CMOS MEMS planar micro fluxgate magnetic ensor.