Semiconductor device and driving method thereof

• US 20070018823A1
• Filed: 05/25/2006
• Published: 01/25/2007
• Est. Priority Date: 05/30/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kurokawa, Yoshiyuki
• Granted Patent: US 7,738,839 B2
• Time in Patent Office: Days
• US Class Current: 340/572.100
• CPC Class Codes: G06K 19/0705 the battery being connected to a power saving arrangement
• CPC Class Codes: G06K 19/0707 the arrangement being capable of collecting energy from external energy sources, e.g. thermocouples, vibration, electromagnetic radiation G06K19/0702 takes precedence
• CPC Class Codes: G06K 19/0712 the arrangement being capable of triggering distinct operating modes or functions dependent on the strength of an energy or interrogation field in the proximity of the record carrier active means for hindering electromagnetic reading or writing G06K19/07336
• 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: G07F 19/20 Automatic teller machines [ATMs]

Abstract

A state control register is provided in addition to the arithmetic circuit and communication circuit in a semiconductor device operated with wireless communication. Operation of an arithmetic circuit which consumes large power is stopped in transmitting or receiving data, that is, in the case where the operating magnetic field varies, whereas the arithmetic circuit can be operated in the case where the operating magnetic field does not vary. In the case where the operating magnetic field varies, a large capacity power supply is not required by realizing the function that is minimum required for the reception or transmission by a receiving circuit or a transmitting circuit. That is, a high-level arithmetic process can be carried out by a small-scale power supply circuit. In this manner, a high-functional and low-power consumption semiconductor device can be provided, which is a structure suitable for a semiconductor device provided with a large-scale circuit.

Claims

1. A semiconductor device comprising:

an antenna for transmitting and receiving a communication signal;

a receiving circuit for discriminating the communication signal;

an arithmetic circuit for performing a decoding and encoding process for encoded receiving and transmitting data;

a transmitting circuit for transmitting an arithmetic result of the arithmetic circuit; and

a state control register for stopping operation of the arithmetic circuit when receiving the communication signal and stopping operation of the receiving circuit and the transmitting circuit when operating the arithmetic circuit.

5. The semiconductor device according to any one of claims 1 to 4, wherein the receiving circuit, the arithmetic circuit, the transmitting circuit, and the state control register are formed of thin film transistors over a substrate having an insulating surface.

2. A semiconductor device comprising:

an antenna for transmitting and receiving a communication signal;

a receiving circuit for discriminating the communication signal;

an arithmetic circuit including a read only memory for storing a program of an arithmetic process and a working memory for storing content of the arithmetic process, for processing data by carrying out the program in accordance with content of decoded data;

a transmitting circuit for transmitting an arithmetic result of the arithmetic circuit; and

a state control register for stopping operation of the arithmetic circuit when receiving the communication signal and stopping operation of the receiving circuit and the transmitting circuit when operating the arithmetic circuit.

3. A semiconductor device comprising:

an antenna for transmitting and receiving a communication signal;

a receiving circuit for discriminating the communication signal;

an arithmetic circuit for performing a decoding and encoding process for encoded receiving and transmitting data;

a transmitting circuit for transmitting an arithmetic result of the arithmetic circuit; and

a state control register for operating the receiving circuit while stopping operation of the arithmetic circuit when an operating magnetic field varies and for stopping the receiving circuit while operating the arithmetic circuit when the operating magnetic field does not vary.

4. A semiconductor device comprising:

an antenna for transmitting and receiving a communication signal;

a receiving circuit for discriminating the communication signal;

an arithmetic circuit including a read only memory for storing a program of an arithmetic process and a working memory for storing content of the arithmetic process, for processing data by carrying out the program in accordance with content of decoded data;

a transmitting circuit for transmitting an arithmetic result of the arithmetic circuit; and

a state control register for operating the receiving circuit while stopping operation of the arithmetic circuit when an operating magnetic field varies and for stopping the receiving circuit while operating the arithmetic circuit when the operating magnetic field does not vary.

6. A driving method of a semiconductor device including a receiving circuit for discriminating a communication signal, an arithmetic circuit, a transmitting circuit for transmitting an arithmetic result of the arithmetic circuit, and a state control register for controlling operation of the arithmetic circuit, the receiving circuit and the transmitting circuit;

comprising;

demodulating the communication signal and discriminating an SOF signal, reception data and an EOF signal;

changing a state of the state control register into an arithmetic processing state when the EOF signal is received;

performing an arithmetic process in accordance with the reception data in the arithmetic circuit;

processing a result of the arithmetic process to be a communication signal in accordance with a format and outputting to a modulating circuit;

changing the state of the state control register into a transmission processing state after the arithmetic process is completed; and

changing the state of the control register into a reception processing state when transmission is completed.

7. A driving method of a semiconductor device including a receiving circuit for discriminating a communication signal, an arithmetic circuit, a transmitting circuit for transmitting an arithmetic result of the arithmetic circuit, and a state control register for controlling operation of the arithmetic circuit, the receiving circuit and the transmitting circuit;

comprising;

demodulating the communication signal and discriminating an SOF signal, reception data and an EOF signal;

changing a state of the state control register into an arithmetic processing state when the EOF signal is received;

decoding encoded data and performing an arithmetic process of predetermined content in accordance with content of the data in the arithmetic circuit;

changing the state of the state control register into a transmission processing state after the arithmetic process is completed; and

changing the state of the control register into a reception processing state when transmission is completed.