Semiconductor integrated circuit
A semiconductor device includes NAND gates and switches to form a circuit to hold data, and a capacitor electrically connected to the circuit via a transistor to store the data held in the circuit. The transistor has a channel formation region including an oxide semiconductor.
1. A semiconductor device comprising:
a first NAND gate comprising a first input terminal, a second input terminal, and an output terminal;
a second NAND gate comprising a first input terminal, a second input terminal, and an output terminal;
a switch comprising a first terminal and a second terminal;
a transistor comprising a first terminal, a second terminal, and a gate; and
a capacitor comprising a first terminal and a second terminal,
wherein the output terminal of the first NAND gate is electrically connected to the first terminal of the switch,
wherein the second terminal of the switch is electrically connected to the first input terminal of the second NAND gate,
wherein the output terminal of the second NAND gate is electrically connected to the first input terminal of the first NAND gate and the first terminal of the transistor,
wherein the second terminal of the transistor is electrically connected to the first terminal of the capacitor, and
wherein the transistor comprises a channel formation region comprising an oxide semiconductor.
2. The semiconductor device according to claim 1 , wherein the oxide semiconductor comprises indium and zinc.
3. The semiconductor device according to claim 1 , wherein the second terminal of the capacitor is configured to be supplied with a fixed potential.
4. The semiconductor device according to claim 1 , wherein the switch is configured to be controlled in accordance with a clock signal.
5. A central processing unit comprising a register comprising the semiconductor device according to claim 1 .
6. A Semiconductor device comprising:
a first NAND gate comprising a first input terminal, a second input terminal, and an output terminal;
a second NAND gate comprising a first input terminal, a second input terminal, and an output terminal;
a first switch comprising a first terminal and a second terminal;
a third NAND gate comprising a first input terminal, a second input terminal, and an output terminal,
a fourth NAND gate comprising a first input terminal, a second input terminal, and an output terminal,
a second switch comprising a first terminal and a second terminal;
a third switch comprising a first terminal and a second terminal;
a transistor comprising a first terminal, a second terminal, and a gate; and
a capacitor comprising a first terminal and a second terminal,
wherein the output terminal of the first NAND gate is electrically connected to the first terminal of the first switch,
wherein the second terminal of the first switch is electrically connected to the first input terminal of the second NAND gate and the first terminal of the third switch,
wherein the output terminal of the second NAND gate is electrically connected to the first input terminal of the first NAND gate and the first terminal of the transistor,
wherein the output terminal of the third NAND gate is electrically connected to the first terminal of the second switch,
wherein the second terminal of the second switch is electrically connected to the first input terminal of the fourth NAND gate,
wherein the output terminal of the fourth NAND gate is electrically connected to the first input terminal of the third NAND gate and the second terminal of the third switch,
wherein the second terminal of the transistor is electrically connected to the first terminal of the capacitor, and
wherein the transistor comprises a channel formation region comprising an oxide semiconductor.
7. The semiconductor device according to claim 6 , wherein the oxide semiconductor comprises indium and zinc.
8. The semiconductor device according to claim 6 , wherein the second terminal of the capacitor is configured to be supplied with a fixed potential.
9. The semiconductor device according to claim 6 , wherein each of the first switch, the second switch, and the third switch is configured to be controlled in accordance with a clock signal.
10. The semiconductor device according to claim 6 , wherein the second input terminal of the first NAND gate is electrically connected to the second input terminal of the fourth NAND gate.
11. The semiconductor device according to claim 6 , wherein the second input terminal of the second NAND gate is electrically connected to the second input terminal of the third NAND gate.
12. A semiconductor device comprising:
a sequential circuit comprising:
a first NAND gate comprising a first input terminal, a second input terminal, and an output terminal;
a second NAND gate comprising a first input terminal, a second input terminal, and an output terminal;
a first switch comprising a first terminal and a second terminal;
a first transistor comprising a first terminal, a second terminal, and a gate; and
a capacitor comprising a first terminal and a second terminal; and
a second transistor comprising a first terminal, a second terminal, and a gate,
wherein the output terminal of the first NAND gate is electrically connected to the first terminal of the first switch,
wherein the second terminal of the first switch is electrically connected to the first input terminal of the second NAND gate,
wherein the output terminal of the second NAND gate is electrically connected to the first input terminal of the first NAND gate and the first terminal of the first transistor,
wherein the second terminal of the first transistor is electrically connected to the first terminal of the capacitor,
wherein the first terminal of the second transistor is electrically connected to the sequential circuit, and
wherein the first transistor comprises a channel formation region comprising an oxide semiconductor.
13. The semiconductor device according to claim 12 , wherein the oxide semiconductor comprises indium and zinc.
14. The semiconductor device according to claim 12 , wherein the second terminal of the capacitor is configured to be supplied with a fixed potential.
15. The semiconductor device according to claim 12 , wherein the first switch is configured to be controlled in accordance with a clock signal.
16. A central processing unit comprising a register comprising the semiconductor device according to claim 12 .
17. The semiconductor device according to claim 12 , comprising a power-gating control circuit electrically connected to the gate of the second transistor.
18. The semiconductor device according to claim 17 , wherein the second transistor is configured to control a supply of a power supply potential to the sequential circuit, in accordance with a control by the power-gating control circuit.
19. The semiconductor device according to claim 12 ,
wherein the sequential circuit comprises:
a third NAND gate comprising a first input terminal, a second input terminal, and an output terminal,
a fourth NAND gate comprising a first input terminal, a second input terminal, and an output terminal,
a second switch comprising a first terminal and a second terminal; and
a third switch comprising a first terminal and a second terminal;
wherein the output terminal of the third NAND gate is electrically connected to the first terminal of the second switch,
wherein the second terminal of the second switch is electrically connected to the first input terminal of the fourth NAND gate,
wherein the output terminal of the fourth NAND gate is electrically connected to the first input terminal of the third NAND gate and the second terminal of the third switch, and
wherein the first terminal of the third switch is electrically connected to the first input terminal of the second NAND gate and the second terminal of the first switch.