Investigation of the thermal drift of open-loop Hall Effect current sensor and its improvement

Linear Hall IC can be used for the low price openloop Hall Effect current sensor thanks to its high sensitivity. However, according to the experimental results, its thermal performance is greatly related to the thermal drift coefficient of linear Hall IC and the gain of the amplifying circuit. In this paper, the thermal drift of the zero offset will be improved by two methods. One is to use two Hall ICs, the thermal drift coefficients of which are similar, to build up a differential amplifying circuit to compensate the common thermal drift of the two Hall ICs. Another one is to add a magnetic core for concentrating the magnetic flux. In this way the gain of the amplifying circuit is reduced by increasing the magnetic flux density passed through the Hall IC. Experimental results show that the thermal performance of the optimized current sensor is reasonably improved by the proposed methods.