Patent ID: 8575930

Claim:
A magnetic detection device, comprising: a magnetic detection unit including a magnetic sensor unit and a comparison unit, the magnetic sensor unit detecting a magnetic flux density as a detection signal in magnetic field, amplifying the detection signal and outputting an output signal to the comparison unit as a mode selected from one of a first mode and a second mode of which power consumption is lower than power consumption of the first mode, the comparison unit comparing the output signal and a reference voltage as a threshold level which determines magnetic field being formed or not, and outputting a comparison result; a conversion gain control unit including a mode control unit and a magnetic sensor control unit, the mode control unit being input the comparison result and outputting a mode signal based on the comparison result to the magnetic sensor control unit, the magnetic sensor control unit outputting an output signal to the magnetic sensor unit as the second mode when the mode signal is larger than the threshold level or the first mode when the mode signal is smaller than the threshold level so as to control the magnetic sensor unit; and an intermittent operation control unit controlling the magnetic detection unit and the conversion gain control unit to enable to intermittently operate.