GMR磁量計交流驅動控制電路設計

Design of ac-driven control circuits for GMR magnetometer

莊竣閎(Jun-Hong Juang)

指導教授 ： 鄭振宗 ； 呂志誠

國立臺北科技大學/機電學院/機電整合研究所/碩士(2008年)

摘要

巨磁阻(GMR)磁量計的磁通密度白雜訊可達1 nT/Hz1/2, 動態範圍超過120 dB, 極適於微小磁場測量應用, 例如渦電流偵測與磁源影像。不過, 因磁滯造成的輸出準位漂移, 卻限制了它在極低頻微小磁場的應用, 例如電子羅盤。本研究探討交流驅動GMR磁量計之特性，使磁阻在交流調變磁場下週期性磁飽和來消除零位漂移, 以利電子羅盤等應用。除了以印刷電路板製作驅動電路, 我們並透過國家晶片中心提供的資源, 設計及製作CMOS驅動電路晶片, 探討其特性與未來的應用範圍。

關鍵字

巨磁阻 ； 直流回授 ； 混波電路 ； 電子羅盤

並列摘要

The GMR magnetometer, which has the dynamic range greater than 120 dB and the magnetic-flux-density noise less than 1 nT/Hz1/2, is suitable for the applications in low field sensing, e.g. eddy-current detection and magnetic source imaging. However, the output dc drift caused by the hysteresis of magnetic material limits its capability in sensing the low frequency magnetic fields, e.g. the electric compass. In this work, we develop the ac-driven GMR magnetometer featured with an ac modulation field and dc feedback. In this way, the dc drift is reduced and the field-to-voltage transfer function is increased substantially, facilitating the application in electric compass. Currently, the ac-driven circuits are implemented with the PCB technology. In the near future, we will design and carry out the CMOS chip through the assistance of the National Chip Implementation Center to study their characteristics for practical applications.

並列關鍵字

GMR ； DC feedback ； mixer ； electric compass

參考文獻

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