| 摘要 |
PURPOSE:To simplify circuit constitution and to perform a read without any influence of a noise by turning on analog switch elements for input selections of respective operational amplifiers successively with a specific lag, and turning on analog switch elements for output selection a specific time later. CONSTITUTION:Photosensor elements R1k, R2k...R4k (k=1...8) in a small block are connected to corresponding operational amplifiers OPA1, OPA2...OPA4 through analog switch elements S1k, S2k...S4k for input selection. Analog switches Sjk (j=1, 2...4) which turn turn on and ground elements Sjk when the elements Sjk are on are provided to prevent photocurrents from detouring. Here, the switches Sjk for input selection are turned on for a period with a log of time T, and analog switch elements S1...S4 for output seldcion are turned on a time tau later. Consequently, a spike noise due to the turn-on operation of an element Sjk which is generated in respective outputs of amplifiers OPA1...OPA4 is prevented from appearing in an output signal V0.
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