Circuit for reducing residual offset of integrated hall sensor

Abstract

The invention discloses a circuit for reducing the residual offset of an integrated hall sensor. The circuit employs rotating current modulation and high-pass filtering, and enables offset and low-frequency 1/f noise, which are generated by a hall device, to be eliminated in advance, and then further eliminates hall offset through a subsequent demodulation circuit. Therefore, the circuit is stronger in capability of eliminating the hall device offset. A signal demodulated by the hall sensor is enabled to be modulated into a high-frequency signal through a feedback modulator, and the high-frequency signal serves as a feedback signal and is transmitted to a difference-difference amplifier for amplification along with a hall signal outputted by a rotating current modulator, thereby forming a closed-loop signal conditioning circuit, and further reducing the residual offset caused by the signal conditioning circuit. The circuit is simple in structure, is easy to achieve circuit integration, cannot increase the manufacture cost, and can obtain low residual offset.

Description

technical field [0001] The invention relates to a signal processing circuit, in particular to a circuit for reducing the residual offset of an integrated Hall sensor. Background technique [0002] The Hall sensor is a magnetoelectric conversion element based on the Hall effect. With its simple process, small size, low production cost, easy installation, wide operating voltage range, long service life, high measurement accuracy, dust-proof, oil-proof, etc. Advantages, has been widely used in industrial frequency conversion control, transportation, medical systems, consumer electronics and various smart instruments and other fields. [0003] However, the integrated Hall sensor based on the silicon process has low magnetic field sensitivity and serious offset, so the weak Hall signal must be amplified and the offset signal eliminated through the corresponding signal conditioning circuit. However, the Hall signal output by the Hall sensor still carries a large residual offset, ...

AI Technical Summary

Problems solved by technology

At present, the dynamic offset cancellation technology of two-phase rotating current is used to eliminate Hall offset, but it cannot effectively eliminate the offset caused by package stress and junction field effect, so the residual offset is relatively large

On the other hand, the signal conditioning circuit that eliminates the offset and amplifies the Hall signal, including the amplifier, demodulator, sample and hold circuit itself also has a large offset voltage, especially the demodulator recovers the high-frequency signal modulated by the rotating current In the process of reaching the low frequency signal, due to the non-ideal type of the switch in the circuit, it also causes a large residual offset

However, there is no good way to eliminate the residual offset caused by the signal conditioning circuit

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