| 摘要 |
PROBLEM TO BE SOLVED: To switch the amount of a driving current to each circuit, according to the power supply voltage or the environmental temperature, and to properly reduce current consumption of each circuit even when the power supply voltage or the environmental temperature varies. SOLUTION: The detector is provided with: a pyroelectric element 1; a current/voltage conversion circuit 2 for converting a fine current signal therefrom into a voltage signal; a voltage amplification circuit 3 for selectively amplifying a prescribed frequency component of the thus converted voltage signal; a detection circuit 4 for comparing the thus amplified voltage signal with a prescribed threshold voltage; an output circuit 5 for outputting a human body detection signal on the basis of the comparison result by this; and a driving current switching circuit 6 for outputting the driving currents thereto, in which the driving current is distributed from the driving current switching circuit 6 to a part of each circuit on the basis of a reference current, and in which the driving current is distributed to the rest part of each circuit, on the basis of one of the plurality of kinds of the switched and outputted reference currents. COPYRIGHT: (C)2005,JPO&NCIPI |
