RFID (radio frequency identification) and IC card

• US 6,972,662 B1
• Filed: 08/15/2000
• Issued: 12/06/2005
• Est. Priority Date: 03/07/2000
• Status: Expired due to Term

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Technology Corporation (Renesas Electronics Corporation)
• Inventors: Watanabe, Kazuki, Oonishi, Tadashi, Yoshigi, Hiroshi, Yuyama, Miki, Ohkawa, Takehiro
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): YANG, CLARA I
• Application Number:
  US09/639,753
• Time in Patent Office: 1,939 Days
• Field of Search: 340/10.1, 340/10.34, 340/10.42, 340/10.33
• US Class Current: 340/10.1
• 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

Abstract

An RFID which provides a wide working voltage range and general versatility at low cost, without the need for changing its internal circuit design due to external factors. In the RFID, there is provided an arrangement that a low impedance state is given when its internal data communication circuit is in a reset state.

Claims

1. An RFID comprising:

an antenna for receiving power to drive a semiconductor circuit device and for transmitting and receiving signals; and

first means for releasing inner elements of said semiconductor device from a reset state which is an inactive state of said inner elements and putting said inner elements in an active state upon detection of a condition that a voltage attained by rectifying an AC wave induced on said antenna is higher than a predetermined voltage level;

wherein, when said reset state is released, information can be transmitted from said antenna to an external apparatus according to signals which are generated in said semiconductor circuit device by controlling two states of impedance of said semiconductor circuit device which are a high impedance state and a low impedance state, and

wherein, in said reset state, said impedance is maintained at said low impedance state.

2. The RFID according to claim 1,

wherein a reset release voltage means for releasing said inner elements from said reset state is substantially equal to a logic working guarantee voltage of an IC that is part of said RFID.

3. The RFID according to claim 2,

wherein said reset release voltage for releasing said inner elements from said reset state is equal to a reset voltage for putting said inner elements in said inactive state at the start of logic working of the IC after releasing said reset state.

4. An IC card which has the RFID according to claim 1.

5. An RFID comprising:

an antenna; and

first means for releasing inner elements of said semiconductor device from a reset state which is an inactive state of said inner elements and putting said inner elements in an active state upon detection of a condition that a DC voltage attained by rectifying an AC wave induced on said antenna is higher than a threshold level;

wherein, when said reset state is released, signal transmission from said antenna to an external apparatus can be performed according to signals which are generated in said semiconductor circuit device by controlling two states of impedance of said semiconductor circuit device which are a high impedance state and a low impedance state,

wherein, when said DC voltage is lower than said threshold level, said semiconductor circuit device is put in said reset state, and

wherein, in said reset state, said impedance is decreased to a low state.

6. An RFID comprising:

an integrated circuit element having memory means, logic processing means, and power-on-reset means for releasing said logic processing means from a reset state which is an inactive state of said logic processing means and putting said logic processing means in an active state; and

an antenna for receiving power and signals from an external apparatus and for supplying said power and signals to said memory means and logic processing means;

wherein, when a voltage applied to said power-on-reset means is lower than a threshold level, impedance of said integrated circuit element is maintained at a low state.

7. An RFID comprising:

an integrated circuit element having communication means, a logic circuit and power-on-reset means for releasing said logic circuit tram a reset state which is an inactive state of said logic circuit and putting said logic circuit in an active state; and

an antenna for receiving power and signals from an external apparatus and for supplying said power and signals to said communication means and logic circuit;

wherein, when a voltage applied to said power-on-reset means is lower than a threshold level, impedance of said IC device is maintained at a low state, and

wherein, when a reset state is released, signal transmission from said antenna to said external apparatus is performed according to signals which are generated in said integrated circuit element by controlling a state of said impedance of said integrated circuit element.

8. An RFID comprising:

an integrated circuit element having memory means, logic processing means and power-on-reset means for releasing said logic processing means from a reset state which is an inactive state of said logic processing means and putting said logic circuit in an active state;

wherein, when a voltage applied to said power-on-reset means is lower than a threshold level, impedance of said integrated circuit element is maintained at a low state.

9. An RFID comprising:

an integrated circuit element having communication means, a logic circuit and power-on-reset means for releasing said logic circuit from a reset state which is an inactive state of said logic circuit and putting said logic circuit in an active state;

wherein, when a voltage applied to said power-on reset means is lower than a threshold level, impedance of said integrated circuit element is maintained at a low state, and

wherein, when a reset state is released, signal transmission to an external apparatus is performed according to signals which are generated in said integrated circuit element by controlling a state of said impedance of said integrated circuit element.

10. An RFID comprising:

an integrated circuit element having communication means, a logic circuit and power-on-reset means for releasing said logic circuit from a reset state which is an inactive state of said logic circuit and putting said logic circuit in an active state; and

an antenna for receiving power and signals from an external apparatus and for supplying said power and signals to said communication means and logic circuit;

wherein, when a voltage applied to said power-on-reset means is lower than a threshold level, impedance of said integrated circuit element is maintained at a low state, and

wherein, when a reset state is released, signal transmission from said antenna to said external apparatus is performed according to signals which are generated in said integrated circuit element by repeating an operation that a terminal of a load resistor whose another terminal is connected with a terminal of a coil of said antenna is connected to ground potential through a switching element and an operation that said terminal of said load resistor is disconnected from said ground potential by said switching element.

11. An RFID comprising:

an integrated circuit element having communication means, a logic circuit and power-on-reset means for releasing said logic circuit from a reset state which is an inactive state of said logic circuit and putting said logic circuit in an active state; and

an antenna for receiving power and signals from an external apparatus and for supplying said power and signals to said communication means and logic circuit)

wherein, when a voltage applied to said power-on-reset means is lower than a threshold level, a terminal of a load resistor whose another terminal is connected with a terminal of a coil of said antenna is connected to ground potential through a switching element.

12. An IC card which has the RFID according to claim 11.