Low-noise linear Hall sensor reading circuit and working method thereof

Abstract

The invention relates to a low-noise linear Hall sensor reading circuit and a working method thereof. The circuit comprises a Hall element, a rotary current circuit, a first amplifier, a chopper, a second amplifier, a PTAT current generation circuit, a switch capacitance notching filter and a buffer, wherein the Hall element is connected with the rotary current circuit, the output end of the rotary current circuit is connected with the input end of the first amplifier, the output end of the first amplifier is connected with the input end of the chopper, the output end of the chopper is connected with the input end of the second amplifier, the output end of the second amplifier is connected with the input end of the switch capacitance notching filter, the output end of the switch capacitance notching filter is connected with the input end of the buffer, the PTAT current generation circuit is connected with the input end of the second amplifier, and the output end of the buffer servers as the output end of the low-noise linear Hall sensor reading circuit. According to the circuit and the working method thereof provided by the invention, the ripple amplitude of the circuit can be reduced while the offset voltage and 1 / f noise of the circuit can be effectively eliminated, and thus the whole circuit accuracy is improved.

Description

technical field [0001] The invention relates to a low-noise linear Hall sensor readout circuit and a working method thereof. Background technique [0002] In recent years, Hall sensors based on CMOS technology have many advantages such as low cost, low power consumption, high reliability, high integration and strong anti-interference ability, and Hall sensors can measure pressure, speed, acceleration through a series of conversions , angular velocity, current and other non-electrical quantities make the Hall sensor widely used in the fields of automobile, smart home, industrial production, power management, aerospace and military. However, for linear Hall sensors, if they are used in automotive and industrial fields that require high precision and can work stably in a large temperature range, higher requirements are placed on the performance of linear Hall sensors, requiring Hall The sensor has better temperature characteristics and accuracy while satisfying low noise outpu...

AI Technical Summary

Problems solved by technology

Due to the piezoresistive effect generated by the packaging stress and the Seebeck effect between different materials, the Hall element will generate a large offset voltage; in addition, due to the defects of the CMOS process, the thickness of the N well of the Hall element is not uniform, so the Hall element The resistance of the bridge arm of the component is not consistent, resulting in an offset voltage; at the same time, the readout circuit will also introduce a series of noise, such as thermal noise, flicker noise, etc.

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