SEMICONDUCTOR DEVICE AND DRIVING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a new semiconductor device and a driving method thereof.SOLUTION: The present invention electrically connects a node (volatility) which maintains data properly rewritten by calculation processing to a node which will store the data through a source and a drain of a transistor in which a channel is formed on an oxide semiconductor layer. The transistor has an extremely low off current. Therefore, leakage of an electric charge from the latter node through the transistor hardly occurs. As a result, data can be maintained even for a period at which the supply of electric source voltage is stopped in the latter node. Means which sets an electric potential of the latter node as a predetermined electric potential is also provided. Specifically, means is provided which supplies an electric potential corresponding to 1 or 0 which is data stored in the latter node from a previous node to the latter node.