Research And Design Of Low Power Linear Hall Sensor

In the permanent magnet motor control process,in order to cut costs and improve stability,linear Hall position sensors are used instead of photoelectric encoders to detect the rotor position information.At the same time,due to the presence of offset voltage and flicker noise,the detection accuracy of the linear Hall sensor is seriously affected;The key techniques of low offset voltage and low power can improve the output accuracy,reliability and application range of the linear Hall sensor.Therefore,designing a linear Hall sensor with low power consumption and low offset voltage has important theoretical significance and engineering application value.By analyzing the source of the offset voltage generated by the Hall plate,it is concluded that the hall plate with square structure that minimizes mechanical str ess and thermal stress can achieve higher sensitivity and lower offset voltage.In order to reduce the offset voltage of the hall plate,the extra offset voltage and flicker noise introduced in the signal processing circuit,compared with the commonly used offset and noise elimination techniques,it is proposed that on the basis of chopping,the tracking-holding techniques is realized by using the capacitance working in different stages to eliminate the offset voltage and flicker noise.By analyzing the typical application scenarios of linear Hall sensors,a method to reduce the power consumption of linear Hall sensors in different modes is proposed.It mainly controls the linear Hall sensors to enter sleep or wake-up mode.through the sleep wake-up mode switching circuit according to the output of different signals from the host computer.When the linear Hall sensor is in the wake-up mode,it can also reduce the chopping frequency through the frequency configurable oscillator to reduce power consumption according to the user's output accuracy requirements.At the same time,the key module circuits such as the sleep/active mode switching circuit,instrument amplifier,oscillator and output stage circuit are designed,and the calculation methods of key parameters are listed in detail,and the low offset voltage and low power linear hall sensor is designed.Based on Dongbu HiTek 0.18um BCD simulation library file,the whole circuit is simulated and analyzed combined with Hspice software.The simulation results verified the feasibility and correctness of the theoretical analysis and design method.Finally,based on the Dongbu HiTek 0.18um BCD design rule file,the layout design of the whole circuit is realized by cadence software,which is verified by DRC and LVS.The post-simulation verification is realized after extracting the parameters.The results verify the feasibility of the designed linear Hall sensor layout.