Memory device and signal processing circuit

• US 8,964,450 B2
• Filed: 05/17/2012
• Issued: 02/24/2015
• Est. Priority Date: 05/20/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ishizu, Takahiko
• Primary Examiner(s): Tran, Anthan
• Application Number:
  US13/473,696
• Publication Number:
  US 20120294068A1
• Time in Patent Office: 1,013 Days
• Field of Search: 365/149, 365/185.21
• US Class Current: 365/149
• CPC Class Codes: G11C 11/412 using field-effect transistors only
• CPC Class Codes: G11C 11/419 Read-write [R-W] circuits
• CPC Class Codes: G11C 5/10 for interconnecting capacitors

Abstract

A memory device which can keep a stored logic state even when the power is off is provided. A signal processing circuit including the memory device, which achieves low power consumption by stopping supply of power, is provided. The memory device includes a logic circuit including a first node, a second node, a third node, and a fourth node; a first control circuit connected to the first node, the second node, and the third node; a second control circuit connected to the first node, the second node, and the fourth node; a first memory circuit connected to the first node, the first control circuit, and the second control circuit; and a second memory circuit connected to the second node, the first control circuit, and the second control circuit.

Claims

1. A semiconductor device comprising:

a memory circuit comprising a first transistor and a capacitor;

a logic circuit comprising a second transistor, a third transistor, a fourth transistor, and a fifth transistor; and

a control circuit comprising a sixth transistor and a seventh transistor,

wherein a first terminal of the first transistor is electrically connected to one electrode of the capacitor,

wherein a second terminal of the first transistor is electrically connected to a first terminal of the second transistor, a first terminal of the third transistor, a gate of the fourth transistor, a gate of the fifth transistor, and a gate of the sixth transistor,

wherein a second terminal of the second transistor is electrically connected to a first terminal of the fourth transistor, a first terminal of the sixth transistor, and a first terminal of the seventh transistor,

wherein the first terminal of the sixth transistor is directly connected to the first terminal of the seventh transistor,

wherein a second terminal of the sixth transistor is directly connected to a second terminal of the seventh transistor,

wherein a second terminal of the third transistor is electrically connected to a first terminal of the fifth transistor, and

wherein a gate of the second transistor and a gate of the third transistor are electrically connected to a second terminal of the fourth transistor and a second terminal of the fifth transistor.

2. The semiconductor device according to claim 1, wherein the first transistor comprises a channel formation region formed in an oxide semiconductor.

3. The semiconductor device according to claim 2, wherein the oxide semiconductor comprises two or more elements selected from indium, gallium, tin, and zinc.

4. The semiconductor device according to claim 1, further comprising a precharge circuit,

wherein a first terminal of the precharge circuit is electrically connected to the second terminal of the first transistor, the first terminal of the second transistor,

the first terminal of the third transistor, the gate of the fourth transistor, the gate of the fifth transistor, and the gate of the sixth transistor, and

wherein a second terminal of the precharge circuit is electrically connected to the gate of the second transistor, the gate of the third transistor, the second terminal of the fourth transistor, and the second terminal of the fifth transistor.

5. The semiconductor device according to claim 1, wherein each of the third transistor and the fifth transistor is a p-channel transistor.

6. The semiconductor device according to claim 1, wherein a plurality of the semiconductor devices is arranged in matrix.

7. The semiconductor device according to claim 1, further comprising a switch electrically connected to the logic circuit,

wherein the switch is configured to output a data signal to the logic circuit in response to a control signal,

wherein the logic circuit is configured to hold the data signal in a period during which a first power supply voltage is supplied,

wherein the control circuit is configured to output a second power supply potential to the logic circuit in accordance with the data signal,

wherein the memory circuit is configured to hold the data signal in response to a second control signal, and

wherein the memory circuit is configured to hold the data signal during the supply of the first power supply voltage is stopped.

8. A semiconductor device comprising:

a first memory circuit comprising a first transistor and a first capacitor;

a second memory circuit comprising a second transistor and a second capacitor;

a logic circuit comprising a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor;

a first control circuit comprising a seventh transistor and an eighth transistor;

a second control circuit comprising a ninth transistor and a tenth transistor; and

a precharge circuit,

wherein a first terminal of the first transistor is electrically connected to one electrode of the first capacitor,

wherein a first terminal of the second transistor is electrically connected to one electrode of the second capacitor,

wherein a second terminal of the first transistor is electrically connected to a first terminal of the third transistor, a first terminal of the fourth transistor, a gate of the fifth transistor, a gate of the sixth transistor, a gate of the seventh transistor, a gate of the ninth transistor, and a first terminal of the precharge circuit,

wherein a second terminal of the second transistor is electrically connected to a first terminal of the fifth transistor, a first terminal of the sixth transistor, a gate of the third transistor, a gate of the fourth transistor, a gate of the eighth transistor, a gate of the tenth transistor, and a second terminal of the precharge circuit,

wherein a first terminal of the seventh transistor is directly connected to a first terminal of the eighth transistor,

wherein a second terminal of the seventh transistor is directly connected to a second terminal of the eighth transistor,

wherein a first terminal of the ninth transistor is directly connected to a first terminal of the tenth transistor,

wherein a second terminal of the ninth transistor is directly connected to a second terminal of the tenth transistor,

wherein the first terminal of the seventh transistor and the first terminal of the eighth transistor are electrically connected to a second terminal of the third transistor and a second terminal of the fifth transistor, and

wherein the first terminal of the ninth transistor and the first terminal of the tenth transistor are electrically connected to a second terminal of the fourth transistor and a second terminal of the sixth transistor.

9. The semiconductor device according to claim 8,

wherein the logic circuit comprises first to fourth node,

wherein the first node is electrically connected to the second terminal of the first transistor, the first terminal of the third transistor, and the first terminal of the fourth transistor,

wherein the second node is electrically connected to the second terminal of the second transistor, the first terminal of the fifth transistor, and the first terminal of the sixth transistor,

wherein the third node is electrically connected to the second terminal of the third transistor and the second terminal of the fifth transistor,

wherein the fourth node is electrically connected to the second terminal of the fourth transistor and the second terminal of the sixth transistor,

wherein the first control circuit is configured to output a first potential to the third node depending on a potential of the first node and a potential of the second node,

wherein the second control circuit is configured to output a second potential to the fourth node depending on the potential of the first node and the potential of the second node, and

wherein the precharge circuit is configured to output a third potential which is a potential between the first potential and the second potential to the first node and the second node.

10. The semiconductor device according to claim 9,

wherein the seventh transistor and the eighth transistor are each an n-channel transistor, and

wherein the ninth transistor and the tenth transistor are each a p-channel transistor.

11. The semiconductor device according to claim 10,

wherein a threshold voltage of the n-channel transistor is higher than the third potential and lower than the second potential, and

wherein a threshold voltage of the p-channel transistor is lower than the third potential and higher than the first potential.

12. The semiconductor device according to claim 8, wherein the first transistor and the second transistor each comprise a channel formation region formed in an oxide semiconductor.

13. The semiconductor device according to claim 12, wherein the oxide semiconductor comprises two or more elements selected from indium, gallium, tin, and zinc.

14. The semiconductor device according to claim 8, wherein a plurality of the semiconductor devices is arranged in matrix.

15. (Withdrawn -Currently Amended) A semiconductor device comprising:

a first memory circuit comprising a first transistor and a first capacitor;

a second memory circuit comprising a second transistor and a second capacitor;

a logic circuit comprising a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor;

a first control circuit comprising a seventh transistor and an eighth transistor;

a second control circuit comprising a ninth transistor and a tenth transistor;

a precharge circuit;

a first switch; and

a second switch,

wherein a first terminal of the first transistor is electrically connected to one electrode of the first capacitor,

wherein a first terminal of the second transistor is electrically connected to one electrode of the second capacitor,

wherein a second terminal of the first transistor is electrically connected to a first terminal of the third transistor, a first terminal of the fourth transistor, a gate of the fifth transistor, a gate of the sixth transistor, a gate of the seventh transistor, a gate of the ninth transistor, and a first terminal of the first switch,

wherein a second terminal of the second transistor is electrically connected to a first terminal of the fifth transistor, a first terminal of the sixth transistor, a gate of the third transistor, a gate of the fourth transistor, a gate of the eighth transistor, a gate of the tenth transistor, and a first terminal of the second switch,

wherein a second terminal of the first switch is electrically connected to a first terminal of the precharge circuit,

wherein a second terminal of the second switch is electrically connected to a second terminal of the precharge circuit,

wherein a first terminal of the seventh transistor is directly connected to a first terminal of the eighth transistor,

wherein a second terminal of the seventh transistor is directly connected to a second terminal of the fourth eighth transistor,

wherein a first terminal of the ninth transistor is directly connected to a first terminal of the tenth transistor,

wherein a second terminal of the ninth transistor is directly connected to a second terminal of the tenth transistor,

wherein the first terminal of the seventh transistor and the first terminal of the eighth transistor are electrically connected to a second terminal of the third transistor and a second terminal of the fifth transistor, and

wherein the first terminal of the ninth transistor and the first terminal of the tenth transistor are electrically connected to a second terminal of the fourth transistor and a second terminal of the sixth transistor.

16. The semiconductor device according to 15, wherein the first transistor and the second transistor each comprise a channel formation region formed in an oxide semiconductor.

17. The semiconductor device according to claim 15, wherein a plurality of the semiconductor devices is arranged in matrix.

18. The semiconductor device according to claim 15,

wherein the logic circuit comprises first to fourth node,

wherein the first node is electrically connected to the second terminal of the first transistor, the first terminal of the third transistor, and the first terminal of the fourth transistor,

wherein the second node is electrically connected to the second terminal of the second transistor, the first terminal of the fifth transistor, and the first terminal of the sixth transistor,

wherein the third node is electrically connected to the second terminal of the third transistor and the second terminal of the fifth transistor,

wherein the fourth node is electrically connected to the second terminal of the fourth transistor and the second terminal of the sixth transistor,

wherein the first control circuit is configured to output a first potential to the third node depending on a potential of the first node and a potential of the second node,

wherein the second control circuit is configured to output a second potential to the fourth node depending on the potential of the first node and the potential of the second node, and

wherein the precharge circuit is configured to output a third potential which is a potential between the first potential and the second potential to the first node and the second node.

19. The semiconductor device according to claim 18,

wherein the seventh transistor and the eighth transistor are each an n-channel transistor, and

wherein the ninth transistor and the tenth transistor are each a p-channel transistor.

20. The semiconductor device according to claim 19,

wherein a threshold voltage of the n-channel transistor is higher than the third potential and lower than the second potential, and

wherein a threshold voltage of the p-channel transistor is lower than the third potential and higher than the first potential.