Power transmission system, IC card and information communication system using IC card

• US 6,427,065 B1
• Filed: 08/16/2000
• Issued: 07/30/2002
• Est. Priority Date: 09/13/1996
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hayashi, Yoshihiko, Nagai, Kenji, Suga, Takashi, Yoshino, Ryouzou
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): Trinh, Sonny
• Application Number:
  US09/639,070
• Time in Patent Office: 713 Days
• Field of Search: 455/41, 455/39, 455/73, 455/572, 455/343, 455/127, 455/558, 455/573, 455/80, 340/10.1, 340/10.4, 235/492, 235/494, 235/487, 342/51, 343/867, 343/868, 343/701
• US Class Current: 455/41.1
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0715 the arrangement including means to regulate power transfer to the integrated circuit
• 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: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• 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: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 7/005 with variable reactance for tuning the antenna
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

The present invention comprises a power transmission system, an IC card, and an information communication system using an IC card. In the power transmission system, power is transmitted by radio from the power transmission device to the IC card. In the IC card, the transmitted induced power is converted into a DC voltage, the transmitted induced power or a voltage corresponding to the induced power is detected, and a desired DC voltage to be suppled to the internal circuit is obtained in controlling resistance the detected induced power or the voltage corresponding to the induced power.

Claims

1. A power transmission and information communication system in which power is transmitted by radio wave from a reader and/or writer device to an IC card and information is communicated by radio wave between the reader and/or writer device and the IC card, said IC card comprising:

a converter circuit including a first antenna having a resonance circuit for receiving said transmitted radio wave and a rectifier circuit which converts an induced power received in said antenna into a DC voltage in rectifying it, the DC voltage being supplied to an internal circuit,

a detector circuit portion for detecting one of the induced power obtained from said first antenna of the converter circuit and a voltage corresponding to said induced power, and

a transmitting unit which transmits an information by a radio wave to the reader and/or writer device, the information concerning one of the induced power and the voltage detected by said detector circuit portion,

said reader and/or writer device comprising;

a receiving unit which receives said information by the radio wave being transmitted from the transmitting unit of the IC card,

a control power supply circuit which controls an output of high frequency power based on the information received by the receiving unit, and

a power transmitting unit having a second antenna for transmitting the output of high frequency power by the radio wave, the output of high frequency power being controlled by said control power supply circuit,

wherein said system provides an arrangement so that information communication can be performed by the radio wave between an information communication portion of said reader and/or writer device and said internal circuit of the IC card.

2. A power transmission and information communication system according to claim 1, wherein in the case of power transmission by the radio wave from the second antenna of said reader and/or writer device to the first antenna of the IC card and in the case of information communication being performed by said arrangement using the radio wave between the information communication portion of said reader and/or writer device and said internal circuit of the IC card, the first antenna on the IC card is used as a first common antenna and the second antenna in the reader and/or writer is used as a second common antenna.

3. A power transmission and information communication system according to claim 2, wherein said control power supply circuit comprises a power supply portion which generates the high frequency power, an encoder circuit which encodes input information communication data to be transmitted, and a modulator which superimposes an amplitude-modulated signal obtained from the encoder circuit upon a signal obtained from the power supply portion, and said power transmitting unit comprises a power feeder circuit which feeds power based on the signal obtained from said modulator, and said second antenna which generates said radio wave corresponding to current fed by said power feeder circuit.

4. A power transmission and information communication system in which power is transmitted by radio wave from a reader and/or writer device to an IC card and information is communicated by radio wave between the reader and/or writer device and the IC card, said IC card comprising:

a converter circuit including a first antenna having a resonance circuit for receiving said transmitted radio wave and a rectifier circuit which converts an induced power received in said antenna into a DC voltage in rectifying it, the DC voltage being supplied to an internal circuit,

a detector circuit which detects one of the induced power and a voltage corresponding to said induced power, and

a transmitting unit which transmits an information by a radio wave to said reader and/or writer device, the information concerning one of the induced power and the voltage detected by said detector circuit,

said reader and/or writer device comprising;

a receiving unit which receives said information by the radio wave being transmitted from the transmitting unit of the IC card,

a control power supply circuit which controls an output of high frequency power based on the information received by the receiving unit, and

a power transmitting unit having a second antenna for transmitting the output of high frequency power by the radio wave, the output of high frequency power being controlled by said control power supply circuit,

wherein said system provides an arrangement so that information communication can be performed by the radio wave between an information communication portion of said reader and/or writer device and said internal circuit of the IC card.

5. A power transmission and information communication system according to claim 4, wherein in the case of power transmission by the radio wave from the second antenna of said reader and/or writer device to the first antenna of the IC card and in the case of information communication being performed by said arrangement using the radio wave between the information communication portion of said reader and/or writer device and said internal circuit of the IC card, the first antenna on the IC card is used as a first common antenna and the second antenna in the reader and/or writer device is used as a second common antenna.

6. A power transmission and information communication system according to claim 5, herein said control power supply circuit comprises a power supply portion which generates the high frequency power, an encoder circuit which encodes input information communication data to be transmitted, and a modulator which superimposes an amplitude-modulated signal obtained from the encoder circuit upon a signal obtained from the power supply portion, and said power transmitting unit comprises a power feeder circuit which feeds power based on the signal obtained from said modulator, and said second antenna which generates said radio wave corresponding to current fed by said power feeder circuit.

7. A power transmission and information communication system, including:

an IC card comprising;

a converter circuit including a first antenna having a resonance circuit for receiving a radio wave being transmitted from a reader and/or writer device, and a rectifier circuit which converts an induced power in said antenna into a DC voltage in rectifying it, and

an internal circuit to be supplied with the DC voltage which is converted in said rectifier circuit of said converter circuit,

said reader and/or writer device comprising;

a detector unit which detects an information corresponding to relative distance between the IC card and the reader and/or writer device,

a control power supply circuit which controls by varying a level of a high frequency power based on the information corresponding to relative distance detected by the detector unit and generates a controlled level of the high frequency power, and

a power transmitting unit having a second antenna for transmitting the controlled level of the high frequency power being generated from said control power supply circuit to the first antenna of the converter circuit of the IC card by the radio wave,

wherein said system provides an arrangement so that information communication can be performed by a radio wave between an information communication portion of said reader and/or writer device and said internal circuit of the IC card.

8. A power transmission and information communication system according to claim 7, wherein in the case of power transmission by the radio wave from the second antenna of said reader and/or writer device to the first antenna of the IC card and in the case of information communication being performed by said arrangement using the radio wave between the information communication portion of said reader and/or writer device and said internal circuit of the IC card, the first antenna on the IC card is used as a first common antenna and the second antenna in the reader and/or writer device is used as second common antenna.

9. A power transmission and information communication system according to claim 8, wherein said control power supply circuit comprises a power supply portion which generates the high frequency power, an encoder circuit which encodes input information communication data to be transmitted, and a modulator which superimposes an amplitude-modulated signal obtained from the encoder circuit upon a signal obtained from the power supply portion, and said power transmitting unit comprises a power feeder circuit which feeds power based on the signal obtained from said modulator, and said second antenna which generates said radio wave corresponding to current fed by said power feeder circuit.