Infrared detector
View Patent ↗Provide is an infrared detector that has a simple configuration, has a high amplification factor, and is configured to operate at low voltage. An NMOS transistor at an output stage of a pyroelectric infrared detection element serves as a common source amplifier circuit in which a source is connected to GND via a resistor and a capacitor that are connected in parallel.
1. An infrared detector for detecting a change in incident amount of infrared ray, comprising:
a pyroelectric infrared detection element, including:
a transistor comprising a drain terminal and a source terminal;
wherein the drain terminal is connected to an output terminal of the infrared detector; and
a ground terminal connected to a ground;
a first resistor connected between the drain terminal and a power supply terminal;
a second resistor connected between the source terminal and the ground; and
a capacitor connected between the source terminal and the ground and connected in parallel to the second resistor, wherein as a gate voltage of the transistor increases, the capacitor is configured to maintain a source voltage not to increase with the gate voltage; and
wherein an increased amount of a drain current flows through the first resistor and the increased amount of the drain current corresponds to a value determined by multiplying an increased amount of a gate voltage of the transistor by a K value of the transistor.