Semiconductor device, electronic appliance using semiconductor device, and document using semiconductor device

• US 8,803,663 B2
• Filed: 12/22/2009
• Issued: 08/12/2014
• Est. Priority Date: 12/25/2008
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ishii, Masato, Atsumi, Tomoaki
• Primary Examiner(s): Wu, Daniel
• Assistant Examiner(s): BAMERT, JOHN J
• Application Number:
  US12/645,082
• Publication Number:
  US 20100163631A1
• Time in Patent Office: 1,694 Days
• Field of Search: 340/10.33, 340/10.51, 340/10.52
• US Class Current: 340/10.33
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: H01L 28/10 Inductors

Abstract

A semiconductor device capable of wireless communication which has low power consumption in a step for decoding an encoded signal to obtain data is provided. The semiconductor device includes an antenna configured to convert received carrier waves into an AC signal, a rectifier circuit configured to rectify the AC signal into a DC voltage, a demodulation circuit configured to demodulate the AC signal into an encoded signal, an oscillator circuit configured to generate a clock signal having a certain frequency by supply of the DC voltage, a synchronizing circuit configured to generate a synchronized encoded signal by synchronizing the encoded signal obtained by demodulating the AC signal with the clock signal, a decoder circuit configured to decode the synchronized encoded signal into a decoded signal, and a register configured to store the decoded signal as a clock (referred to as a digital signal).

Claims

1. A semiconductor device comprising:

an antenna configured to receive carrier waves and convert the carrier waves into an AC signal;

a rectifier circuit configured to rectify the AC signal into a DC voltage;

a demodulation circuit configured to demodulate the AC signal into an encoded signal;

an oscillator circuit configured to generate a first clock signal by supply of the DC voltage;

a synchronizing circuit configured to generate a synchronized encoded signal by synchronizing the encoded signal with use of the first clock signal;

a decoder circuit configured to decode the synchronized encoded signal into a digital signal; and

a register configured to store the digital signal with use of the synchronized encoded signal delayed from the first clock signal as a second clock signal.

2. The semiconductor device according to claim 1, further comprising a constant voltage circuit configured to supply a constant DC voltage to the oscillator circuit.

3. The semiconductor device according to claim 1, wherein a frequency of the second clock signal is lower than a frequency of the first clock signal.

4. The semiconductor device according to claim 1, wherein the semiconductor device is configured to receive power without contact.

5. The semiconductor device according to claim 1, wherein the synchronized encoded signal is supplied to the decoder circuit and the register.

6. The semiconductor device according to claim 1, wherein the digital signal is a stabilized voltage.

7. The semiconductor device according to claim 1,

wherein a frequency of the first clock signal is lower than a frequency of the carrier waves, and

wherein the frequency of the first clock signal has a certain oscillation frequency.

8. The semiconductor device according to claim 1, wherein the second clock signal is delayed by two cycles of the first clock signal.

9. An electronic appliance using the semiconductor device according to claim 1.

10. A semiconductor device comprising:

an antenna configured to receive carrier waves and convert the carrier waves into an AC signal;

a rectifier circuit configured to rectify the AC signal into a DC voltage;

a demodulation circuit configured to demodulate the AC signal into an encoded signal;

a decoder circuit configured to decode the encoded signal into a decoded signal;

a first unit configured to generate a first clock signal by supply of the DC voltage;

a second unit configured to generate a synchronized encoded signal by synchronizing the encoded signal with use of the first clock signal; and

a third unit configured to store data obtained by decoding the synchronized encoded signal in the decoder circuit, with the synchronized encoded signal delayed from the first clock signal utilized as a second clock signal.

11. The semiconductor device according to claim 10, further comprising a constant voltage circuit configured to supply a constant DC voltage to the first unit.

12. The semiconductor device according to claim 10, wherein a frequency of the second clock signal is lower than a frequency of the first clock signal.

13. The semiconductor device according to claim 10, wherein the semiconductor device is configured to receive power without contact.

14. The semiconductor device according to claim 10, wherein the synchronized encoded signal is supplied to the decoder circuit and the third unit.

15. The semiconductor device according to claim 10, wherein the data is a stabilized voltage.

16. The semiconductor device according to claim 10,

wherein a frequency of the first clock signal is lower than a frequency of the carrier waves, and

wherein the frequency of the first clock signal has a certain oscillation frequency.

17. The semiconductor device according to claim 10, wherein the second clock signal is delayed by two cycles of the first clock signal.

18. An electronic appliance using the semiconductor device according to claim 10.

19. A driving method for a semiconductor device including an antenna, a rectifier circuit, a demodulation circuit, an oscillator circuit, a synchronized circuit, a decoder circuit, and a register, comprising the steps of:

receiving carrier waves;

converting the carrier waves into an AC signal by the antenna;

rectifying the AC signal into a DC voltage;

demodulating the AC signal into an encoded signal;

generating a first clock signal in the oscillator circuit supplied with the DC voltage;

generating a synchronized encoded signal by synchronizing the encoded signal with use of the first clock signal;

supplying the synchronized encoded signal to the decoder circuit and the register;

decoding the synchronized encoded signal into a digital signal; and

storing the digital signal to the register with use of the synchronized encoded signal delayed from the first clock signal as a second clock signal.

20. The driving method of a semiconductor device, according to claim 19,

wherein the semiconductor device further comprises a constant voltage circuit, and

wherein the driving method further comprises the step of supplying a constant DC voltage to the oscillator circuit.

21. The driving method of a semiconductor device, according to claim 19, wherein a frequency of the second clock signal is lower than a frequency of the first clock signal.

22. The driving method of a semiconductor device, according to claim 19, wherein the semiconductor device is configured to receive power without contact.

23. The driving method of a semiconductor device, according to claim 19, wherein the synchronized encoded signal is supplied to the decoder circuit and the register.

24. The driving method of a semiconductor device, according to claim 19, wherein the digital signal is a stabilized voltage.

25. The driving method of a semiconductor device, according to claim 19,

wherein a frequency of the first clock signal is lower than a frequency of the carrier waves, and

wherein the frequency of the first clock signal has a certain oscillation frequency.

26. The driving method of a semiconductor device, according to claim 19, wherein the second clock signal is delayed by two cycles of the first clock signal.