Non-contact data carrier system

• US 6,489,883 B1
• Filed: 04/27/1998
• Issued: 12/03/2002
• Est. Priority Date: 04/30/1997
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Iiyama, Keiichi, Asaka, Nobuyoshi
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): Bangachon, William L
• Application Number:
  US09/066,918
• Time in Patent Office: 1,681 Days
• Field of Search: 307/10.2, 307/104, 307/116, 307/652, 340/825.54, 340/825.31, 340/825.69, 340/825.72, 340/505, 340/510, 340/10.1, 340/10.33, 340/10.2, 340/10.34, 340/10.3, 340/10.52, 340/5.2, 340/5.65, 340/5.61, 340/426, 340/5.72, 343/711, 343/712
• US Class Current: 340/5.1
• CPC Class Codes: B60R 25/04 operating on the propulsion system, e.g. engine or drive motor
• CPC Class Codes: B60R 25/245 where the antenna reception area plays a role
• CPC Class Codes: B60R 25/406 Power supply in the remote key
• 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: 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 2009/00634 Power supply for the lock
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/65 using means for sensing the user's hand
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks

Abstract

A non-contact data carrier includes a battery, an electric-supply circuit for rectifying a received carrier signal and generating power, and an electric-supply switching circuit for comparing the voltage of the battery and the voltage generated by the electric-supply circuit and selecting either one of the voltages. When the battery can supply power, long-distance communication can be performed by supplying power from the battery. In case of battery exhaustion, power is supplied from the electric-supply circuit which receives a stronger carrier signal by using the non-contact IC card in the proximity of a question unit and rectifies the carrier signal, so that the function of the non-contact data carrier is maintained.

Claims

1. A non-contact data carrier comprising:

carrier signal detection means for detecting a carrier signal transmitted from a question unit, for comparing an amplitude level of said carrier signal with a predetermined reference level and for placing said non-contact data carrier into a sleep state on the basis of the comparison result;

a main circuit unit comprising a memory for holding data, a demodulation circuit, a modulation circuit and a control circuit;

switching means for switching output condition of power supplied from an internal battery to said main circuit unit;

electric-supply means for rectifying said carrier signal and generating a voltage; and

electric-supply switching means to which an output of said electric-supply means and an output of said switching means are input, said electric-supply switching means outputting a voltage to said main circuit unit, wherein

said carrier signal detection means compares the amplitude level of said carrier signal and the predetermined reference level, and when said level of said carrier signal is higher than said reference level, said switching means goes into an “

ON”

state so that power of said battery is supplied to said electric-supply switching means, and

when said switching means is in the “

ON”

state, a voltage value of said battery and a value of said voltage generated by said electric-supply means are compared, and when said voltage value of said battery is higher than said voltage generated by said electric-supply means, said electric-supply switching means outputs power of said battery to said main circuit unit.

2. A non-contact data carrier comprising:

transmission-reception means for receiving a carrier signal from a question unit and for transmitting data to said question unit;

carrier signal detection means for comparing an amplitude level of the carrier signal with a predetermined level;

a demodulation circuit for demodulating the carrier signal;

a modulation circuit for modulating the data to be transmitted to said question unit,

a control circuit for controlling said modulation circuit;

said control circuit receiving an output of said demodulation circuit;

electric-supply means for rectifying the carrier signal and generating a voltage;

switching means for supplying power from an internal battery; and

electric-supply switching means connected to said electric supply means and to said switching means for supplying power to said modulation circuit, said demodulation circuit and said control circuit, wherein said switching means provides the power from said battery to said electric-supply switching means when the amplitude level of the carrier signal is greater than the predetermined level and, if the amplitude level of the carrier signal is less than the predetermined level, the non-contact data carrier is brought into a sleep state in which the power from said battery is supplied only to said carrier signal detection means and to said switching means and wherein said electric-supply switching means includes a comparator for comparing a voltage value of said battery and a voltage value of said electric-supply means, and switches said electric-supply switching means to said electric-supply means when the voltage value of said electric-supply means is higher than the voltage value of said battery.