OPERATIONAL AMPLIFIER CIRCUIT, BAND-PASS FILTER CIRCUIT AND INFRARED SIGNAL PROCESSING CIRCUIT

摘要

PPROBLEM TO BE SOLVED: To provide an operational amplifier circuit improving power supply noise elimination characteristics without reducing a dynamic range. PSOLUTION: The operational amplifier circuit 5 comprises: a transconductance amplifier circuit 1 for converting a differential input voltage to a differential output current; a common feedback circuit 2 for outputting a control signal to the transconductance amplifier circuit 1 so that the DC voltage level of the differential output voltage of the transconductance amplifier circuit 1 becomes equal to a reference voltage vref; a voltage supply circuit 2 for supplying a voltage less influenced by a power supply voltage to the common feedback circuit 2 as the reference voltage vref; and an output load ZL to which the differential output voltage of the transconductance amplifier circuit 1 is applied and which constitutes the output terminal of the operational amplifier circuit 5. Also, the respective circuits are supplied with, the power supply voltage vdd from a power supply terminal. PCOPYRIGHT: (C)2008,JPO&INPIT