Current sensor and current measuring device and method based on differential measurement

The invention discloses a current sensor and a current measuring device and method based on differential measurement. Through a differential measurement mode, two tunnel magnetic resistance sensitive chips are used, measurement is carried out at two openings of an open-close type magnetic core, and if external environment magnetic field interference exists, the signals measured by two sensitive units at the magnetic core are common-mode signals with the same direction and the equal magnitude,the magnetic field signals generated by the current passing through the wire in the magnetic core are differential mode signals with opposite directions and the equal magnitude, the common-mode interference can be filtered and the differential-mode signals can be amplified through subtraction, and the value of the current passing through the wire can be calculated through the measured magnitude of the magnetic field. The measurement mode can effectively filter the interference of an external magnetic field, improves the m