| 摘要 |
PURPOSE:To make a charge detection circuit in a wide dynamic range in high S/N by a method wherein the first reset gate and the second reset gate are formed splitably to be opened and closed at a timing shift. CONSTITUTION:N type channels 16a, 16b are formed between n<+>type diffused layers 13 and 18 while reset gates 17a, 17b are formed above the layers 13, 18. The reset gate 17a is closed at a time t1. At this time, the level of KTC noise (K: Boltzmann's constant T: absolute temperature) is decided by a small floating capacity CFD in an FD layer 14 cut off by the reset gate 17a. Next, the other reset gate 17b is also closed with the reset gate 17a left closed at another time t2. Then, at the other time t3, the reset gate 17a is opened with the reset gate 17b left closed. Through these procedures, the floating capacity CRS1 of reset gate 17a is added to the floating capacity CFD so that the charge storage capacity may be increased to expand the dynamic range.
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