Gain adjusting circuit

Abstract

Abstract PURPOSE:To decrease the occupying area of the circuit, by simplifying the gain adjusting circuit and making the circuit low in the power consumption, through the input of an output signal divided by a resistor division consisting of variable resistors and a fixed resistor to the inverting input terminal of an operational amplifier. CONSTITUTION:A feedback loop of an operational amplifier 6 is provided with variable resistors consisting of polysilicon fuses F11-F13 and resistors R11-R13 and a fixed resistor R10, and the gain is changed by changing the resistance value of the variable resistor. In the variable resistor, the resistance value with 8 values in the increment of DELTAR, can be selected through the combination of the blown fuse, by DELTAR(where; =R11-R11/Rf is the resistance value of the fuses F11-F13) in case of the blown fuse F11 by 2DELTAR in case of the blown fuse F12 and by 4DELTAR in case of blown F13.

Inventors

• 👤 Yoshiaki Kuraishi

Bibliographic Details