PURPOSE: To provide a driving device of an image sensor which is capable of reducing the offset voltage of an amplifier and improving the S/N of reading original information.
CONSTITUTION: An original information signal Vin read from an image sensor is supplied to a signal line L (1) and then, first to fourth analog switches 24, 26, 28 and 30 are turned ON. As a result, first and third capacitors 25, 29 are charged. Next, the first to fourth analog switches 24, 26, 28 and 30 are turned OFF, a switch 4 (1) is turned ON and the electric charge stored in the signal line L (1) is discharged. Subsequently, the first and third analog switches 24, 28 are turned ON. As a result, the potential VB of a point B becomes VB =-100Vin+Vos3 (Vos 3 is the offset voltage of a third amplifier 23.), and when an analog switch 5 (1) is turned ON in this condition, the signal VB appears on an output line OUTL. Because offset voltage Vos 3 is small, the offset voltage of the amplifier can be reduced.
OZAWA TAKASHI
ITO HISAO
NISHIHARA YOSHIO
| JPS57113515U | 1982-07-14 |