A Highly Sensitive CMOS Digital Hall Sensor for Low Magnetic Field Applications

School of Electronic Science & Engineering, Nanjing University, Nanjing 210093, China.
Sensors (Impact Factor: 2.25). 12/2012; 12(2):2162-74. DOI: 10.3390/s120202162
Source: PubMed


Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 μm high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ± 2 mT magnetic field and output a digital Hall signal in a wide temperature range from -40 °C to 120 °C.

1 Follower
26 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: A single-chip three-dimensional(3-D)Hall sensor for high-accuracy three-axis magnetic-field measurements is presented. The chip contains a 3-D Hall device, the analog signal conditioning circuit, an A/D converter and the digital signal-processing unit. The 3-D Hall device contains horizontal and vertical Hall elements. The horizontal Hall element measures the perpendicular component, and four vertical Hall elements measure the two in-plane components of a magnetic flux. With the detailed analysis of the essential factors affecting Hall voltage, the signal conditioning circuit based on spinning current technique is provided, which works in 100kHz and can cancel the offset, reduce the 1/f noise and amplify the signal. The digital signal-processing unit provides the high-accuracy mapping algorithm between measured values and target values.
    Proceedings of the 2013 Third International Conference on Instrumentation, Measurement, Computer, Communication and Control; 09/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper studies the effects of the covering layers on the performance of a cross-like Hall plate. Three different structures of a cross-like Hall plate in various sizes are designed and analyzed. The Hall plate sensitivity and offset are characterized using a self-built measurement system. The effect of the P-type region over the active area on the current-related sensitivity is studied for different Hall plate designs. In addition, the correlation between the P-type covering layer and offset is analyzed. The best structure out of three designs is determined. Besides, a modified eight-resistor circuit model for the Hall plate is presented with improved accuracy by taking the offset into account.
    Sensors 12/2014; 15(1):672-86. DOI:10.3390/s150100672 · 2.25 Impact Factor

Preview (2 Sources)

26 Reads
Available from