| 摘要 |
PURPOSE:To lower the power supply voltage of a preamplifier without lowering the sensitivity by connecting a switch to a signal output line and closing the switch in the blanking period. CONSTITUTION:A switch 40 is added to a conventional MOS image pickup element and a signal electric charge on the photodiode 32 of a row selected by vertical scanning pulses v1-v2 is moved to a vertical signal line 25 during the horizontal blanking period, the switch 40 is closed by a reset pulse rp from a terminal 41 to reset the DC potential of a signal output line 23 to a voltage Vv'. Horizontal MOS transistors 27 are conducted sequentially by using horizontal scanning pulses h1-h3 to read a signal and since the switch 40 is opened in such case, no thermal noise by the witch 40 is increased. Thus, since the DC bias is fed to an image pickup element without increasing thermal noise, the AC coupling with a preamplifier is applied to the output of the image pickup element without reducing the sensitivity and the power voltage of the preamplifier is lowered.
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