A circuit suitable for data backup of a logic circuit is provided. The circuit includes first to fourth nodes, a capacitor, first to third transistors, and first and second circuits. Data can be loaded and stored between the circuit and the logic circuit. The first node is electrically connected to a data output terminal of the logic circuit. The second node is electrically connected to a data input terminal of the logic circuit. The capacitor is electrically connected to the third node. The first transistor controls electrical continuity between the first node and the third node. The second transistor controls electrical continuity between the second node and the third node. The third transistor controls electrical continuity between the second node and the fourth node. The first and second circuits have functions of raising gate voltage of the first transistor and raising gate voltage of the second transistor, respectively.
