THERMAL IMAGE LEAD-OUT CIRCUIT USING CUT-OFF FREQUENCY CHANGE

摘要

PURPOSE: A thermal image lead-out circuit using cut-off frequency change is provided to improve the response sensibility of the sensor and the integrity by employing a high gain amplifier occupying a small area while improving the high and low frequency noise. CONSTITUTION: A thermal image lead-out circuit using cut-off frequency change includes a coupling capacitor(C1) connected to an input terminal at a side, a CMOS inverter connected to at the other side of a plate of the coupling capacitor for amplifying electric signals output from a thermal image sensor, a variable resistance sensor(Rs) equivalently connected between the other side of the coupling capacitor and an output terminal of the CMOS inverter for forming a high band pass filter together with the coupling capacitor, MOS transistor(M3) connected to the output terminal of the CMOS inverter at a drain and to the other side of the coupling capacitor at a gate as a resistor, and a capacitor(C2) connected between a source of the MOS transistor and the ground for forming a low band pass filter together with the MOS transistor.