| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an infrared detection type human body detection apparatus which takes a short time since a power source is turned on until circuit operation is stabilized, and can quickly be recovered even if external noise is applied during circuit operation. <P>SOLUTION: In an infrared detection type human body detection apparatus, one end of a pyroelectric element 1 is connected to the ground, and the other end is connected to an inverting input terminal of an operational amplifier 2, a feedback circuit Cf composed of a capacitor is connected between the output terminal and the inverting input terminal of the operational amplifier 2 to constitute an alternating current feedback circuit. A series circuit composed of a direct current feedback circuit 3 and an input resistance Ri is further provided between the output terminal and the inverting input terminal of the operational amplifier 2, and feedback is performed by the input resistance Ri. Then, both ends of the input resistance Ri are limited in potential different by connecting a limiter circuit 4 to the input resistance Ri in parallel to each other. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
