Hall element offset voltage elimination device and elimination method

Abstract

The invention relates to a Hall element offset voltage elimination device and method, and the device comprises the steps: 1) a Hall element which outputs a voltage signal; 2) a signal modulation circuit which modulates an input Hall voltage signal; (3) chopping operation amplification: chopping the modulated Hall signal; the clock circuit is connected with the signal modulation circuit and the chopper operational amplifier; and 5) a filter circuit for filtering the high-frequency offset signal output by the chopper operational amplifier and outputting an accurate Hall voltage signal. Unwanted offset signals generated by the Hall element are separated from the magnetic field voltage in a frequency domain through a modulation circuit, and the magnetic field voltage is recovered to a base band through subsequent demodulation; meanwhile, direct-current offset is modulated into a high-frequency signal, the magnetic field voltage can pass through a subsequent low-pass filter, the modulated offset voltage is suppressed, and finally accurate output of a useful signal is guaranteed. The Hall sensor has the beneficial effects that the Hall signal is modulated by utilizing the chopping technology, the input noise and failure voltage of the Hall sensor are effectively reduced, and the performance of the Hall sensor is improved.

Description

technical field [0001] The invention relates to the field of Hall sensors, in particular to a device and method for eliminating the offset voltage of a Hall element. Background technique [0002] The Hall sensor is a magnetic field sensor based on the Hall effect. It is widely used in many fields due to its low cost, low power consumption, and small footprint. The Hall element has the advantages of solid structure, small size, light weight, long life, and good linearity. However, the Hall voltage generated by the Hall sensor is extremely weak, and there is a large offset voltage and noise in the system. The technology to eliminate the offset and noise is very critical. [0003] With the continuous development of MEMS technology, people gradually pay attention to the research of high-performance Hall sensor. The offset of the Hall sensor mainly comes from two aspects: the offset voltage of the post-stage signal processing circuit, and the offset voltage of the Hall plate. ...

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Problems solved by technology

[0004] After searching the existing patents, the Chinese patent "An Eight-phase Rotating Current Circuit for Hall Sensors" (Patent No.: CN201710376518.9) uses an eight-phase rotating current circuit based on the current output mode and its dynamic offset The elimination method, which uses a Hall element to eliminate the offset voltage, has a simple structure, but the noise in the post-stage signal processing circuit is not suppressed, so it is not suitable for manufacturing high-precision Hall sensors

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