A hybrid multi-path CMOS magnetic sensor with 76 ppm/°C sensitivity driftA Hybrid Multi-Path CMOS Magnetic Sensorwith 76 ppm/˚C Sensitivity Drift

Conference paper (2016)

Authors

J. Jiang Electronic Instrumentation -

Kofi A.A. Makinwa Microelectronics

K.A.A. Makinwa Microelectronics

Research Group

Electronic Instrumentation () (TU Delft)

Temperature measurement Temperature sensors Coils Spinning Magnetic sensors Sensivity

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Published Date

20-10-2016

Language

English

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Electronic Instrumentation

Abstract

This paper presents a temperature-stable system for wide-bandwidth contactless current sensing. It employs a multipath combination of Hall sensors (low frequencies) and coils (high frequencies) to sense the magnetic field produced by a current-carrying conductor under a chip. To cancel the effect of earth's common-mode field, a differential sensing arrangement is used. This is further exploited to stabilize the Hall sensor's temperature drift with the help of a self-generated AC commonmode field. In a test chip fabricated in a 0.18 μm CMOS process, the stabilization scheme reduces the Hall sensor's sensitivity drift from 22% to 1% from -45°C to 105°C, corresponding to a temperature coefficient of 76 ppm/°C. The complete system has a bandwidth of 3 MHz, which represents a 10x improvement on previous low-drift CMOS magnetic sensors.