Information Processing Terminal, IC Card, Portable Communication Device, Wireless Communication Method, and Program

• US 20070246546A1
• Filed: 04/18/2007
• Published: 10/25/2007
• Est. Priority Date: 04/20/2006
• Status: Active Grant

• Current Assignee: FeliCa Networks, Inc
• Original Assignee: FeliCa Networks, Inc
• Inventors: YOSHIDA, Yuko
• Granted Patent: US 7,975,907 B2
• Time in Patent Office: Days
• US Class Current: 235/492
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/28 using the near field of leaky cables, e.g. of leaky coaxial cables
• CPC Class Codes: H04B 5/72 for local intradevice communication

Abstract

Herein disclosed an information processing terminal that is allowed to carry out contactless data transmission/reception with a read/write device by use of a magnetic field, the information processing terminal including: a data transmitter/receiver configured to generate an induced voltage from a magnetic field generated from the read/write device at the time of data reception, and sends a transmission signal to the read/write device at the time of data transmission; a signal processor configured to generate a response signal based on the induced voltage; and a load modulator configured to include a load of which value is changed based on the induced voltage and carry out load modulation relating to the transmission signal based on the response signal

Claims

1. An information processing terminal that is allowed to carry out contactless data transmission/reception with a read/write device by use of a magnetic field, the information processing terminal comprising:

a data transmitter/receiver configured to generate an induced voltage from a magnetic field generated from the read/write device at the time of data reception, and sends a transmission signal to the read/write device at the time of data transmission;

a signal processor configured to generate a response signal based on the induced voltage; and

a load modulator configured to include a load of which value is changed based on the induced voltage and carry out load modulation relating to the transmission signal based on the response signal.

2. The information processing terminal according to claim 1, wherein

the load modulator includes:

a resistance variable circuit that has a variable resistance and serves as the load;

a load variation level control circuit that changes the resistance of the resistance variable circuit based on the induced voltage; and

a connection circuit that allows the load modulation based on the response signal.

3. The information processing terminal according to claim 1, further comprising:

an internal power supply; and

an internal supply voltage detector configured to detect an internal supply voltage output from the internal power supply and output an internal supply voltage signal dependent upon the internal supply voltage, wherein

the load modulator includes;

a resistance variable circuit that has a variable resistance and serves as the load;

a load variation level control circuit that changes the resistance of the resistance variable circuit based on the induced voltage and the internal supply voltage signal; and

a connection circuit that allows the load modulation based on the response signal.

4. An IC card that is allowed to carry out contactless data transmission/reception with a read/write device by use of a magnetic field, the IC card comprising:

a data transmitter/receiver configured to generate an induced voltage from a magnetic field generated from the read/write device at the time of data reception, and sends a transmission signal to the read/write device at the time of data transmission;

a signal processor configured to generate a response signal based on the induced voltage; and

a load modulator configured to include a load of which value is changed based on the induced voltage and carry out load modulation relating to the transmission signal based on the response signal.

5. The TC card according to claim 4, further comprising:

an internal power supply; and

an internal supply voltage detector configured to detect an internal supply voltage output from the internal power supply and output an internal supply voltage signal dependent upon the internal supply voltage, wherein

the load modulator includes;

a resistance variable circuit that has a variable resistance and serves as the load;

a load variation level control circuit that changes the resistance of the resistance variable circuit based on the induced voltage and the internal supply voltage signal; and

a connection circuit that allows the load modulation based on the response signal.

6. A portable communication device that is allowed to carry out contactless data transmission/reception with a read/write device by use of a magnetic field, the portable communication device comprising:

a data transmitter/receiver configured to generate an induced voltage from a magnetic field generated from the read/write device at the time of data reception, and sends a transmission signal to the read/write device at the time of data transmission;

a signal processor configured to generate a response signal based on the induced voltage; and

a load modulator configured to include a load of which value is changed based on the induced voltage and carry out load modulation relating to the transmission signal based on the response signal.

7. The portable communication device according to claim 6, further comprising:

an internal power supply; and

an internal supply voltage detector configured to detect an internal supply voltage output from the internal power supply and output an internal supply voltage signal dependent upon the internal supply voltage, wherein

the load modulator includes;

a resistance variable circuit that has a variable resistance and serves as the load;

a load variation level control circuit that changes the resistance of the resistance variable circuit based on the induced voltage and the internal supply voltage signal; and

a connection circuit that allows the load modulation based on the response signal.

8. A wireless communication method for contactless data transmission/reception with a read/write device by use of a magnetic field, the method comprising the steps of:

generating an induced voltage from a magnetic field generated from the read/write device;

changing a value of a load based on the induced voltage to thereby adjust power consumed by the load; and

carrying out load modulation with use of the load to thereby allow communication with the read/write device.

9. A program that relates to wireless communication for contactless data transmission/reception with a read/write device by use of a magnetic field and causes a computer to function as an entity comprising:

a unit configured to generate an induced voltage from a magnetic field generated from the read/write device;

a unit configured to change a value of a load based on the induced voltage to thereby adjust power consumed by the load; and

a unit configured to carry out load modulation with use of the load to thereby allow communication with the read/write device.