| 摘要 |
PURPOSE:To shorten the initial amplification time of the whole sense amplifiers and to shorten access time by performing sense amplification in two stages by providing two switches controlled based on independent driving signals and a switch controlled by the potential of a bit line. CONSTITUTION:The switches Q1i, Q2i controlled based on respective independent driving signal and the switch SWi turned on when the potential of the bit line exceeds threshold value, while, turned off when it is less than the threshold value are provided at two current paths connecting the terminal on the other side of a transistor NT for pull-down of each sense amplifier SAi to a part in the neighborhood of each amplifier of a charge extraction line SAN#. The sense amplification in a first stage is performed until the switch SWi is turned off by the driving signal by decreasing the potential of the bit line less than the threshold value after the switch Q1i is turned on by the driving signal, and following that, the sense amplification in a second stage is performed by turning on the switch Q2i by the driving signal. In such a way, it is possible to shorten the initial amplification time for the whole sense amplifiers and the access time. |
