Semiconductor device

• US 20080164978A1
• Filed: 12/31/2007
• Published: 07/10/2008
• Est. Priority Date: 01/10/2007
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Tanada, Yoshifumi
• Granted Patent: US 8,570,151 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: H04B 5/0012 using capacitive coupling
• CPC Class Codes: H04B 5/0062 in RFID [Radio Frequency Identification] Systems
• CPC Class Codes: H04B 5/0081 with antenna coils loop aerials H01Q7/00
• CPC Class Codes: H04B 5/22 Capacitive coupling
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/77 for interrogation

Abstract

It is an object of the present invention to provide a semiconductor device which can generate desired level of a power supply voltage even when the received power of carrier waves is reduced in the semiconductor device, such as RFID tags or the like, which receives and transmits data wirelessly and generates electric power inside using carrier waves. In a storage capacitor portion formed of a plurality of capacitor portions, the plurality of capacitor portions are charged in the state of parallel connection, and at the circuit operation, a high voltage can be taken out from part of or all of the plurality of capacitor portions in series connection corresponding to a power supply voltage in need at that time. Accordingly, when the received power of carrier waves is reduced, i.e. even when a distance between a tag and a reader/writer becomes large, a voltage that is necessary for the circuit operation inside the tag can be assured so as to greatly contribute to increase a communication distance. In addition, electric power can be favorably supplied to a circuit which requires a high driving voltage inside the tag.

Claims

1. A semiconductor device comprising:

an antenna configured to generate an AC voltage from carrier waves;

a rectifier circuit configured to generate a DC voltage from the AC voltage;

a function portion configured to conduct processing in response to a command included in the carrier waves; and

a storage capacitor portion configured to store the DC voltage, comprising;

a first terminal connected to the rectifier circuit and to the function portion;

a second terminal;

first to n-th capacitor elements; and

a plurality of switches,

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in parallel between the first terminal and the second terminal, in a first mode,

wherein the plurality of switches are configured to connect the first to m-th capacitor elements in series between the first terminal and the second terminal, in a second mode,

wherein n is natural number larger than 1, and

wherein m is natural number larger than 1, and smaller than or equal to n.

2. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the rectifier circuit comprises a thin film transistor over the substrate.

3. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the storage capacitor portion comprises a thin film transistor over the substrate.

4. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the antenna is formed over the substrate.

5. The semiconductor device according to claim 1,

wherein the function portion comprise a rewritable memory element group, and

wherein the plurality of switches are configured to enter the second mode when a data included in the carrier waves is written in the memory element group.

7. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the rectifier circuit comprises a thin film transistor over the substrate.

8. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the storage capacitor portion comprises a thin film transistor over the substrate.

9. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the antenna is formed over the substrate.

10. The semiconductor device according to claim 1,

wherein the function portion comprise a rewritable memory element group, and

wherein the plurality of switches are configured to enter the second mode when a data included in the carrier waves is written in the memory element group.

12. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the rectifier circuit comprises a thin film transistor over the substrate.

13. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein at least one of the first storage capacitor portion and the second stage capacitor portion comprises a thin film transistor over the substrate.

14. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the antenna is formed over the substrate.

15. The semiconductor device according to claim 1,

wherein the first function portion comprise a rewritable memory element group, and

wherein the plurality of switches are configured to enter the second mode when a data included in the carrier waves is written in the memory element group.

17. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the rectifier circuit comprises a thin film transistor over the substrate.

18. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein at least one of the first storage capacitor portion and the second stage capacitor portion comprises a thin film transistor over the substrate.

19. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the antenna is formed over the substrate.

20. The semiconductor device according to claim 1,

wherein the first function portion comprise a rewritable memory element group, and

wherein the plurality of switches are configured to enter the second mode when a data included in the carrier waves is written in the memory element group.

22. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the rectifier circuit comprises a thin film transistor over the substrate.

23. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein at least one of the first storage capacitor portion and the second stage capacitor portion comprises a thin film transistor over the substrate.

24. The semiconductor device according to claim 1, further comprising:

a substrate having an insulating surface,

wherein the antenna is formed over the substrate.

25. The semiconductor device according to claim 1,

wherein the first function portion comprise a rewritable memory element group, and

wherein the plurality of switches are configured to enter the second mode when a data included in the carrier waves is written in the memory element group.

6. A semiconductor device comprising:

an antenna configured to generate an AC voltage from carrier waves;

a rectifier circuit configured to generate a DC voltage from the AC voltage;

a function portion configured to conduct processing in response to a command included in the carrier waves; and

a storage capacitor portion configured to store the DC voltage, comprising;

a first terminal connected to the rectifier circuit and to the function portion;

a second terminal;

first to n-th capacitor elements; and

a plurality of switches,

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in parallel between the first terminal and the second terminal, in a first mode,

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in series between the first terminal and the second terminal, in a second mode,

wherein n is natural number larger than 1.

11. A semiconductor device comprising:

an antenna configured to generate an AC voltage from carrier waves;

a rectifier circuit configured to generate a DC voltage from the AC voltage;

a first function portion configured to conduct first processing in response to a first command included in the carrier waves;

a second function portion configured to conduct second processing in response to a second command included in the carrier waves;

a first storage capacitor portion configured to store the DC voltage comprising;

a first terminal connected to the rectifier circuit and to the first function portion;

a second terminal;

first to n-th capacitor elements; and

a plurality of switches, and

a second storage capacitor portion configured to store the DC voltage;

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in parallel between the first terminal and the second terminal, in a first mode,

wherein the plurality of switches are configured to connect the first to m-th capacitor elements in series between the first terminal and the second terminal, in a second mode,

wherein the second storage capacitor portion is connected between the rectifier circuit and the second function portion,

wherein n is natural number larger than 1, and

wherein m is natural number larger than 1, and smaller than or equal to n.

16. A semiconductor device comprising:

an antenna configured to generate an AC voltage from carrier waves;

a rectifier circuit configured to generate a DC voltage from the AC voltage;

a first function portion configured to conduct first processing in response to a first command included in the carrier waves;

a second function portion configured to conduct second processing in response to a second command included in the carrier waves;

a first storage capacitor portion configured to store the DC voltage comprising;

a first terminal connected to the rectifier circuit and to the first function portion;

a second terminal;

first to n-th capacitor elements; and

a plurality of switches, and

a second storage capacitor portion configured to store the DC voltage;

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in parallel between the first terminal and the second terminal, in a first mode,

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in series between the first terminal and the second terminal, in a second mode,

wherein the second storage capacitor portion is connected between the rectifier circuit and the second function portion,

wherein n is natural number larger than 1.

21. A semiconductor device comprising:

an antenna configured to generate an AC voltage from carrier waves;

a rectifier circuit configured to generate a DC voltage from the AC voltage;

a first function portion configured to conduct first processing in response to a first command included in the carrier waves;

a second function portion configured to conduct second processing in response to a second command included in the carrier waves;

a first storage capacitor portion configured to store the DC voltage comprising;

a first terminal connected to the rectifier circuit and to the first function portion;

a second terminal;

first to n-th capacitor elements; and

a plurality of switches, and

a second storage capacitor portion configured to store the DC voltage comprising;

a third terminal connected to the rectifier circuit and to the second function portion;

a fourth terminal; and

plurality of capacitor elements connected in parallel between the third terminal and fourth terminal;

wherein the plurality of switches are configured to connect the first to n-th capacitor elements in parallel between the first terminal and the second terminal, in a first mode,

wherein the plurality of switches are configured to connect the first to m-th capacitor elements in series between the first terminal and the second terminal, in a second mode,

wherein n is natural number larger than 1,

wherein m is natural number larger than 1, and smaller than or equal to n.