Patent ID: 8759772

Claim:
An infrared sensor, comprising: a MOSFET sensor; and a current source MOSFET which is connected to the MOSFET sensor in series and constitutes a constant current source for driving the MOSFET sensor with a constant current, wherein a terminal between the MOSFET sensor and the current source MOSFET constitutes a sensor output terminal, the MOSFET sensor is disposed on a heat-insulated structure, the current source MOSFET is disposed outside the heat-insulated structure, and the MOSFET sensor and the current source MOSFET are constituted by a same conductivity type MOSFET and operate in a subthreshold region, wherein the MOSFET sensor includes a gate-drain short-circuit and the current source MOSFET includes a gate-source short-circuit, and when a voltage between the gate and the source is the same in the MOSFET sensor and the current source MOSFET, a current in the subthreshold region of the MOSFET sensor is set to be smaller than a current in the subthreshold region of the current source MOSFET.