Semiconductor device and wireless communication system using the same

• US 8,305,216 B2
• Filed: 09/07/2011
• Issued: 11/06/2012
• Est. Priority Date: 05/19/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Atsumi, Tomoaki, Shionoiri, Yutaka, Kobayashi, Hidetomo
• Primary Examiner(s): Nguyen, Hung T.
• Application Number:
  US13/226,770
• Publication Number:
  US 20110315780A1
• Time in Patent Office: 426 Days
• Field of Search: 340/572.1, 340/572.4, 340/572.7, 340/572.8, 340/634, 340/653, 235/375, 235/376, 235/380, 235/383, 235/487, 235/492, 455/127.1, 455/269
• US Class Current: 340/572.1
• CPC Class Codes: G06K 19/0708 the source being electromagnetic or magnetic
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card

Abstract

Initialization of a semiconductor device can be efficiently performed, which transmits and receives data through wireless communication. The semiconductor device includes an antenna, a power source circuit, a circuit which uses a DC voltage generated by the power source circuit as a power source voltage, and a resistor. The antenna includes a pair of terminals and receives a wireless signal (a modulated carrier wave). The power source circuit includes a first terminal and a second terminal and generates a DC voltage between the first terminal and the second terminal by using a received wireless signal (the modulated carrier wave). The resistor is connected between the first terminal and the second terminal. In this manner, the semiconductor device and the wireless communication system can transmit and receive data accurately.

Claims

1. A semiconductor device comprising:

a conductive film capable of receiving energy;

a first circuit comprising a first terminal and a second terminal and generating a DC voltage between the first terminal and the second terminal by the energy;

a second circuit using the DC voltage as a power source voltage; and

a resistor electrically connected to the first circuit,

wherein a first terminal of the resistor is electrically connected to the first terminal of the first circuit, and a second terminal of the resistor is electrically connected to the second terminal of the first circuit.

2. The semiconductor device according to claim 1,

wherein the energy is an electromagnetic wave,

wherein the first circuit comprises a rectifying circuit which rectifies the electromagnetic wave and converts the electromagnetic wave to a DC signal and a holding capacitor which smoothes the DC signal outputted from the rectifying circuit, and

wherein the first circuit outputs the DC signal smoothed by the holding capacitor as the DC voltage.

3. The semiconductor device according to claim 1, further comprising a band-pass filter electrically connected to the conductive film.

4. The semiconductor device according to claim 1,

wherein the energy is an electromagnetic wave,

wherein the second circuit using the DC voltage as the power source voltage comprises a demodulation circuit which demodulates the electromagnetic wave, an analyzing circuit which analyzes data demodulated by the demodulation circuit, and a memory which operates based on the data analyzed by the analyzing circuit.

5. The semiconductor device according to claim 1,

wherein the energy is an electromagnetic wave,

wherein the second circuit using the DC voltage as the power source voltage comprises a demodulation circuit which demodulates the electromagnetic wave, an analyzing circuit which analyzes data demodulated by the demodulation circuit, a memory which operates based on the data analyzed by the analyzing circuit, an encoding circuit which encodes the data read from the memory, and a modulation circuit which modulates a carrier wave in accordance with the data encoded by the encoding circuit.

6. The semiconductor device according to claim 1,

wherein the energy is an electromagnetic wave,

wherein the second circuit using the DC voltage as the power source voltage comprises a demodulation circuit which demodulates the electromagnetic wave, an analyzing circuit which analyzes data demodulated by the demodulation circuit, and a memory which operates based on the data analyzed by the analyzing circuit, and

wherein the memory is any one of a DRAM, an SRAM, a FeRAM, a mask ROM, an EPROM, an EEPROM, and a flash memory.

7. The semiconductor device according to claim 1, wherein the resistor has electric resistance of 500 kΩ

to 2 MΩ

.

8. The semiconductor device according to claim 1, wherein the resistor is formed by a semiconductor layer.

9. The semiconductor device according to claim 1,

wherein the second circuit using the DC voltage as the power source voltage comprises a thin film transistor, and

wherein the resistor is formed by a semiconductor layer formed simultaneously with a semiconductor layer which functions as an active layer of the thin film transistor.

10. The semiconductor device according to claim 1,

wherein the second circuit using the DC voltage as the power source voltage comprises a thin film transistor,

wherein the resistor is formed by a semiconductor layer formed simultaneously with a semiconductor layer which functions as an active layer of the thin film transistor, and

wherein an impurity element which imparts conductivity is added to the semiconductor layer of the resistor.

11. The semiconductor device according to claim 1,

wherein the second circuit using the DC voltage as the power source voltage comprises a thin film transistor,

wherein the resistor is formed by a semiconductor layer formed simultaneously with a semiconductor layer which functions as an active layer of the thin film transistor, and

wherein an impurity element which imparts conductivity is added to the semiconductor layer of the resistor at approximately the same concentration as a channel forming region of the thin film transistor.

12. The semiconductor device according to claim 1, wherein the conductive film is any one of a dipole antenna, a patch antenna, a loop antenna, and a Yagi antenna.

13. The semiconductor device according to claim 1,

wherein the energy is an electromagnetic wave, and

wherein the electromagnetic wave is formed by modulating a carrier wave in an analog modulation method or a digital modulation method.

14. The semiconductor device according to claim 1,

wherein the energy is an electromagnetic wave, and

wherein the conductive film transmits and receives the electromagnetic wave by any one of an electromagnetic coupling method, an electromagnetic induction method, and a radio wave method.

15. The semiconductor device according to claim 1, wherein the first circuit is a power source circuit.

16. The semiconductor device according to claim 1, wherein the second circuit is a signal processing circuit.

17. The semiconductor device according to claim 1, wherein the conductive film is an antenna.

18. The semiconductor device according to claim 1, wherein the energy is an electromagnetic wave.