Non-contact IC card

• US 5,212,373 A
• Filed: 10/31/1990
• Issued: 05/18/1993
• Est. Priority Date: 07/03/1990
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Fujioka, Shuzo, Matsubara, Toshiyuki, Furuta, Shigeru
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US07/606,854
• Time in Patent Office: 930 Days
• Field of Search: 235/380, 235/492, 235/437, 902/26, 364/408
• US Class Current: 235/492
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: G06K 19/0705 the battery being connected to a power saving arrangement
• 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: H02J 9/005 using a power saving mode for copiers G03G15/5004
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

In a non-contact IC card, when the card is in a standby mode of operation a CPU provides a command to inhibit the application of a clock signal to digital circuitry including the CPU and/or to inhibit the application of an operating voltage to analog circuitry, except for an antenna circuit and a trigger signal demodulating circuit, so that power consumption in the standby mode is reduced. For transfer of data between the IC card and an external device, a trigger signal derived by demodulating received data in the trigger signal demodulating circuit is used to apply the clock signal to said digital circuitry and the operating voltage to all of the analog circuitry.

Claims

1. A non-contact IC card comprising:

an oscillator circuit for generating a clocking oscillation signal;

digital circuitry, including at least a CPU, ROM, and RAM, said CPU receiving the clocking oscillation signal and producing an internal clock signal from the clocking oscillation signal, said ROM and RAM being operated in response to the internal clock signal;

analog circuitry coupled to said digital circuitry for transmitting data to and receiving data from an external device without contacting the external device; and

an internal power supply battery for providing an operating voltage to said oscillator circuit, said digital circuitry, and said analog circuitry wherein said CPU includes an internal clock inhibit circuit for inhibiting application of the internal clock signal to said ROM and RAM in response to a command produced by said CPU when said non-contact IC card is neither transmitting data to nor receiving data from an external device and for applying the internal clock signal to said digital circuitry in response to receipt of data by said analog circuitry from an external device.

2. A non-contact IC card according to claim 1 wherein said oscillator circuit continues to generate the clocking oscillation signal while application of the internal clock signal to said ROM and RAM is inhibited in response to a command produced by said CPU.

3. A non-contact IC card comprising:

an oscillator circuit for generating a clocking oscillation signal;

digital circuitry, including at least a CPU, ROM, and RAM, said CPU receiving the clocking oscillation signal and producing an internal clock signal from the clocking oscillation signal;

analog circuitry coupled to said digital circuitry for transmitting data to and receiving data from an external device without contacting the external device; and

an internal power supply battery for providing an operating voltage to said oscillator circuit, said digital circuitry, and said analog circuitry including a switching circuit for inhibiting application of the operating voltage from said battery to part of said analog circuitry in response to a command produced by said CPU when said non-contact IC card is neither transmitting data to nor receiving data from an external device and for applying the operating voltage to said analog circuitry in response to receipt of data by said analog circuitry from an external device.

4. A non-contact IC card comprising:

an oscillator circuit for generating a clocking oscillation signal;

digital circuitry, including at least a CPU, ROM, and RAM, said CPU receiving the clocking oscillation signal and producing an internal clock signal from the clocking oscillation signal, said ROM and RAM being operated in response to the internal clock signal;

analog circuitry coupled to said digital circuitry for transmitting data to and receiving data from an external device without contacting the external device;

an internal power supply battery for providing an operating voltage to said oscillator circuit, said digital circuitry, and said analog circuitry wherein said CPU includes an internal clock inhibit circuit for inhibiting application of the internal clock signal to said ROM and RAM in response to a command produced by said CPU when said non-contact IC card is neither transmitting data to nor receiving data from an external device and for applying the internal clock signal to said digital circuitry in response to receipt of data by said analog circuitry from an external device; and

a switching circuit for inhibiting application of the operating voltage from said battery to part of said analog circuitry in response to a command produced by said CPU when said non-contact IC card is neither transmitting data to nor receiving data from an external device and for applying the operating voltage to said analog circuitry in response to receipt of data by said analog circuitry from an external device.

5. A non-contact IC card according to claim 4 wherein said analog circuitry includes an antenna circuit for transmitting data to and receiving data from an external device and a trigger signal demodulating circuit for generating a trigger signal for controlling said CPU wherein, when said non-contact IC card is neither transmitting data to nor receiving data from an external device, application of the operating voltage to said antenna circuit and to said trigger signal demodulating circuit continues and application of the operating voltage to said analog circuitry, excluding said antenna circuit and said trigger signal demodulating circuit, is inhibited.

6. A non-contact IC card according to claim 4 wherein, said oscillator circuit continues to generate the clocking oscillation signal while application of the internal clock signal to said ROM and RAM is inhibited in response to a command produced by said CPU.