Study On Key Technologies In The Design Of Hall Current Sensor

According to the development requirements for advanced industrial and military Hall current sensors,on the basis of the technique and experience of developing Hall current sensor,from the aspects of Hall Element's material selection,components selection and calculation of its parameters,structural design,assembly design,reliability design and so on,this paper presents a method to improve the linearity and precision of the item,and the prototype was developed and tested.In this paper,the material of Hall element is studied,we chose the Hall element which made of GaAs as the sensitive element of the Hall current sensor.The traditional constant current drive circuit is improved,a constant current drive circuit based on three terminal voltage regulator is designed,the circuit parameters are analyzed and calculated,and simulated by Mulitsim.The drive circuit can reduce the temperature drift of the Hall element,it ensure the Hall current sensor's temperature drift less than 4mV in the temperature range-40?~150?.The traditional signal amplifying and zero adjusting circuit is improved,a differential amplifier circuit based on dual operational amplifier and zero output adjusting circuit is designed,the circuit parameters are analyzed and calculated,and simulated by Mulitsim.Benefit from the improved circuit,the linearity of the Hall current sensor is increased to ±0.2FS%,and the accuracy is increased to ±0.25%.In this paper,the material of magnetic core is studied,we chose the magnetic core which made of Fe based Microcrystalline.The formula of the magnetic flux density and the width of the air gap and the current is given,the magnetic flux density in the air gap is calculated.To the Hall current sensor for measuring range ±200A,the optimum size of air gap is 1.5mm,and the result is simulated by ANSYS.In order to meet the national defense industry,resistant to salt fog,fungus,vibration,shock and other environmental requirements,the Hall current sensor's shell parts were made of metal,and the minimum safe clearance of 1kV is determined by calculation.In this paper,the reliability design methods and techniques of Hall current sensor are given,the circuit scheme is analyzed according to GJB/Z 1391-2006,and the reliability improvement method are given.The failure rate of Hall current sensor is calculated.