Research And Design Of The Low Power Digital Switch Hall Effect Sensor

Among the various sensing technologies used to detect magnetic fields,Hall sensors are one of the most commonly used.Hall sensors are capable of replacing mechanical contact switches in industrial automation,wearable devices,and other applications.Among them,millions of digital switch Hall sensors are produced globally each year and are used in a wide variety of applications,such as computers,automobiles,industrial controls and consumer devices.In this paper,how to minimize the power consumption,reduce the chip area,and extend the service life of digital switch Hall sensors has become a key issue.In this paper,a low power digital switch Hall sensor is designed to meet the needs of high-tech market applications and the trend of high integration,high precision and low power consumption.The main research results and innovation points of this paper are as follows.1.This paper researches and implements the offset voltage and noise cancellation technology of Hall elements.By combining the rotation current offset cancellation and the chopper stabilization technology,the induced voltage of the Hall element and the offset voltage and noise of the amplifier circuit are suppressed.By precisely amplifying the Hall sensing signal voltage,and separating the offset voltage from the effective magnetic field signal in the frequency domain by modulation circuit,chopper amplifier and switched capacitor filtering,the overall offset and noise reduction of the sensor is achieved,so that the chip can obtain accurate output according to the magnetic field signal.2.Research and implementation of flux threshold,hysteresis window trim and temperature compensation techniques for digital switched Hall sensors.In order to avoid over-sensitive output jumps in Hall element sensing due to weak external magnetic field jitter,a hysteresis window is set on top of the design of magnetic field trigger and release thresholds,and the hysteresis window threshold can be trimmed by user coding to suit different working scenarios.For the problem that the magnetic sensing sensitivity of Hall sensor is easy to change with temperature,a way to reduce the temperature drift coefficient of Hall element is proposed for Hall element temperature compensation module.3.Design of low power mode for digital switch Hall sensors.For the design requirements of low power consumption of the switch Hall sensor,a periodic hibernation and sampling mode of operation is proposed in this paper.The power supply to the main channel is cut off when the switch Hall sensor enters the hibernation state.After reaching the set time period,it will make the Hall switch enter the sampling and detecting magnetic field state.When the output control circuit acquires the hysteresis output of the comparison circuit,it will cause the timing control signal to retime and the switch Hall sensor will enter the hibernation state again to reduce the power.4.Digital switch Hall sensor signal processing module design and simulation verification.In addition to the module on the main analog signal path,the bandgap reference module,high and low frequency clock generation module are also designed.After the formula derivation and simulation verification,the modules function and perform well,and the indicators meet the expected design goals.Based on the 0.18?m BCD process,the circuit design,simulation verification and layout design were carried out with the help of Cadence software platform,and the chip samples produced by tape-out were tested and verified.