Data exchange system

• US 5,519,386 A
• Filed: 07/14/1994
• Issued: 05/21/1996
• Est. Priority Date: 07/14/1993
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Tobergte, Wolfgang
• Primary Examiner(s): Horabik, Michael
• Application Number:
  US08/274,943
• Time in Patent Office: 677 Days
• Field of Search: 340/825.54, 340/825.72, 340/825.31, 340/870.28, 340/870.31, 340/870.32, 455/41, 455/343
• US Class Current: 340/10.34
• CPC Class Codes: G06K 19/0701 at least one of the integrated circuit chips comprising an arrangement for power management
• CPC Class Codes: G06K 19/0723 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

Abstract

A data exchange system is provided including a fixed station and portable data carrier for transmitting energy between the station and carrier. Both the fixed station and the portable data carrier operate in the active mode and the passive mode. The data carrier operates in an active mode only when energy transfer is required.

Claims

1. A data exchange system for wireless exchange of high-frequency energy and data between a fixed station and a portable data carder, said data exchange system comprising:

a fixed station, wherein said fixed station comprises means for establishing a wireless connection in a first mode of operation corresponding to a rest state and in a second mode of operation corresponding to an active state; and

a portable data carrier, said data carrier being operable in an active mode of operation for transmitting high-frequency energy and data and further being operable in a passive mode of operation, wherein said data carder comprises

(i) an electric circuit for providing data to be transmitted to said fixed station and for processing data which is received from said fixed station,

(ii) a supply device for generating an operating voltage for the electric circuit,

(iii) means for establishing a wireless connection for transmitting high-frequency energy and data and for receiving high-frequency energy and data,

(iv) an energy source,

(v) an oscillator operable during the active mode of said data carrier for triggering the wireless connection establishing means of said data carrier to transmit high-frequency energy and data to said fixed station, and

(vi) a switch connected between the energy source and the oscillator for selectably operating the oscillator as desired to commence a data exchange, wherein an operation of the oscillator via the switch places said data carrier in the active mode, wherein during the active mode the supply device generates the operating voltage for the electric circuit from the energy source via the oscillator, further wherein said fixed station, operating in the first mode, in response to a receipt of transmitted high-frequency energy and data from said data carrier, thereupon begins operating in the second mode, actively transmitting, via the wireless connection establishing means of said fixed station, high-frequency energy and data for subsequent receipt thereof by said data carrier via the wireless connection establishing means of said data carrier, said data carder further comprising

(vii) detection means, responsive to the high-frequency energy received from said fixed station, for switching off the oscillator, thereby switching over said data carrier from the active mode to the passive mode, and further wherein during the passive mode the supply device generates the operating voltage for the electric circuit from the received high-frequency energy.

2. The data exchange system as claimed in claim 1, wherein the means for establishing the wireless connection of said fixed station and said data carrier, together comprise at least a pair of coils, one coil thereof being arranged in said fixed station whereas the other coil is arranged in said data carrier, further wherein the coil arranged in said data carrier further constitutes part of a resonant circuit, still further wherein the resonant circuit constitutes a frequency-determining part of the oscillator.

3. The data exchange system as claimed in claim 1, wherein the energy source is a solar cell.

4. The data exchange system as claimed in claim 1, wherein the energy source is a rechargeable energy source.

5. The data exchange system as claimed in claim 1, further wherein the detection means of said data carrier still further comprises power determining means for determining a power of the high-frequency energy and for supplying, when a prescribed power value is exceeded, the operating voltage from the supply device to a supply output for charging the energy source.

6. The data exchange system as claimed in claim 5, still further wherein said data carrier further comprises a second switch, the second switch for selectively connecting the energy source to the oscillator or to the supply output.

7. The data exchange system as claimed in claim 6, further wherein the second switch is controlled by the power determining means.