A magnetic sensor integrated circuit includes a rectifier circuit, a magnetic field detection circuit, and a timing controller. The rectifier circuit converts an external power into a DC power. The magnetic field detection circuit senses a polarity of an external magnetic field and outputting a magnetic detection signal; and the magnetic field detection circuit includes a first chopping switch, a first amplifier unit and a switched capacitor filter module. The timing controller outputs a first clock signal to the first chopping switch and the first amplifier unit, and a second clock signal delayed for the first clock signal with a first predetermined time to the switched capacitor filter module.