Current sensor with fluxgate

A fluxgate current sensor comprising a magnetic core that extends around a conductor conveying a current for measuring, an excitation coil, an excitation module connected to the excitation coil in order to generate an excitation voltage across the terminals of the excitation coil, a measurement coil conveying an induced measurement current, and a measurement synchronous demodulator connected to the measurement coil for the purpose of multiplying the induced measurement current by a demodulation signal of frequency 2f0 in order to obtain an image voltage that is the image of the current for measuring, the sensor being characterized in that the excitation voltage is obtained from a first voltage of frequency f0 and from a second voltage of frequency 3f0, in that the fluxgate current sensor further includes a servo-control coil conveying an induced servo-control current, and a servo-control synchronous demodulator connected to the servo-control coil for the purpose of multiplying the induced servo-control current by a demodulation signal of frequency 3f0, and in that the servo-control synchronous demodulator is connected to the excitation module in order to servo-control the excitation voltage in such a manner as to cancel the component of frequency 3f0 in the induced servo-control current.