United States Patent (19)
`Tobergte
`
`|||||IIII
`US00551938.6A
`11
`Patent Number:
`5,519,386
`(45) Date of Patent:
`May 21, 1996
`
`54) DATA EXCHANGE SYSTEM
`(75) Inventor: Wolfgang Tobergte, Halstenbek,
`Germany
`73) Assignee: U.S. Philips Corporation, New York,
`N.Y.
`
`21 Appl. No.: 274,943
`22 Filed:
`Jul. 14, 1994
`30
`Foreign Application Priority Data
`Jul. 14, 1993 DE Germany ............................. 43 23 530
`(51) Int. Cl. ..................... G08C 19/00
`52 U.S. Cl. ................................ 3401825.54; 340/825.31;
`340/825.72; 455/343
`58 Field of Search ......................... 340/825.54, 825.72,
`340/825.31, 870.28,870.31, 870.32; 455/41,
`343
`
`56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`4,688,036 8/1987 Hirano ............................... 3401825.54
`
`
`
`DETECTION CIRCUIT
`
`5/1989 Sato ................................... 340/825.72
`4,835,531
`5,317,309 5/1994 Vercelotti et al. ................ 3401825.72
`
`FOREIGN PATENT DOCUMENTS
`3242551 5/1983 Germany.
`9108325 6/1991 WIPO.
`
`Primary Examiner-Michael Horabik
`Attorney, Agent, or Firm-Michael J. Balconi-Lamica;
`David Schreiber
`
`ABSTRACT
`(57)
`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.
`
`7 Claims, 1 Drawing Sheet
`
`RECTFER
`CIRCUIT
`
`PROCESSING
`DEVICE
`(COMPUTER)
`
`Ex.1005
`APPLE INC. / Page 1 of 5
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`U.S. Patent
`
`May 21, 1996
`
`5,519,386
`
`DETECTION CIRCUIT
`
`PROCESSING
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`OSCILLATOR
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`RECEIVER
`SE
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`33 32
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`PROCESSING
`DEVICE
`(COMPUTER)
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`DETECTION CIRCUIT
`14
`- L/10
`11
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`15 L
`50
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`28
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`FIG.2
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`Ex.1005
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`1.
`DATA EXCHANGE SYSTEM
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`5,519,386
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`exchange with a data carrier is actually required. Further
`more, because of the fact that in the active mode of operation
`of the data carrier the means for the wireless connection is
`fed by an oscillator, the remainder of the circuit of the data
`carrier can have a construction exactly like that of a data
`carrier operating in the passive mode only, so that such a
`circuit can be more economically used.
`An oscillator always consists of an active element and one
`or more frequency-determining elements. In an embodiment
`according to the invention of a data exchange system of the
`kind disclosed in De 3242 551 C2, in which the means for
`the wireless connection comprise at least a pair of coils, one
`coil thereof being arranged in the fixed station whereas the
`other coil is arranged in the data carrier and forms part of a
`resonant circuit, this resonant circuit constitutes a fre
`quency-determining part of the oscillator. Thus, the oscilla
`tor additionally requires only one active element, so that an
`extremely simple construction is obtained, or only a very
`limited extension of the known passive data carrier is
`required.
`The energy source can be realized in various ways, for
`example as a solar cell or as a battery as in the known data
`exchange system described above. However, because of the
`portable data carrier preferably being as small as possible,
`thus allowing only for an energy source of small voltline, the
`energy which is stored in this energy source, or which can
`be delivered thereby, is limited. In order to enable never
`theless as prolonged and as reliable use of the data carrier as
`possible, in an embodiment of the invention the energy
`source can be recharged. Because the energy source is
`loaded only briefly each time when the data carrier is used,
`an energy source of very small capacity suffices if frequent
`recharging is readily possible.
`However, this cannot be ensured for all applications, for
`example an application for the opening of the doors of a
`vehicle and for making the starting possible. According to a
`further embodiment of the invention of a data exchange
`system comprising, like the described known system, means
`in the data carrier which responds to the received high
`frequency energy by switching-over the energy source to
`generating the operating voltage from the energy received,
`means is provided for determining the power of the high
`frequency energy to supply, when a power value is
`exceeded, the operating voltage from the supply device to a
`supply output for the recharging of the energy source. This
`embodiment is particularly effective when the energy source
`is an accumulator or a capacitor. When it is ensured that
`during use of the data carrier the distance between the data
`carrier and the fixed station is sufficiently small sufficiently
`frequently, the energy source will be frequently recharged so
`that the data carrier can operate in the active mode practi
`cally an unlimited number of times.
`A particularly simple possibility of recharging the energy
`source is achieved in a further embodiment of the invention
`in that the energy source can be connected as desired, via a
`switch, to the oscillator or to the supply output. Preferably,
`the switch can be controlled by the means for determining
`the power. Automatic switching over then occurs not only
`from the active to the passive mode of operation of the data
`carrier, but at the same time also to the charging mode,
`without intervention by the user of the data exchange system
`being required. When the first and the second power value
`differ, the switch may have a central position in which the
`energy source is connected neither to the oscillator nor to the
`supply output. In the simplest case, however, in this embodi
`ment the first and the second power value are equal, so that
`for an activated data carrier the energy source has two
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`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The invention relates to a data exchange system, com
`prising a fixed station and a portable data carrier which are
`coupled to one another by means for establishing a wireless
`connection for the transmission of high-frequency energy
`and data, the data carrier comprising at least an electric
`circuit with a supply device for generating the operating
`voltage for the circuit from the high-frequency energy
`received or from an energy source.
`2. Discussion of the Related Art
`15
`A data exchange system of this kind is known from WO
`92/08148. The data carrier of the system described therein
`serves to monitor a person in a security area. To this end, the
`data carrier periodically transmits very short, encoded infor
`mation blocks which identity the data carrier and which are
`20
`intercepted by an aerial and processed in a receiver. More
`over, at entrances of the security area there are provided
`interrogation devices which transmit a high-frequency elec
`tromagnetic field that also transfers information. When the
`data carrier approaches such an interrogation device, the
`energy taken up from the high-frequency electromagnetic
`field feeds the circuit of the data carrier and at the same time
`a battery accommodated in the data carrier is switched off,
`that is to say only for as long as the energy of the high
`frequency field taken up by the data carrier is sufficiently
`high. The data carrier then returns its identification to the
`interrogation device which can thus grant access to the
`Security area.
`The interrogation device in this known system continually
`transmits a high-frequency field. Moreover, the interrogation
`device and the aerial with receiver constitute fully separate
`devices. Notably the tact that the interrogation device must
`continually transmit an electromagnetic field not only con
`stitutes a kind of burden to the environment, but also gives
`rise to problems when the energy source present in the
`interrogation device is of limited capacity as is the case in,
`for example, a vehicle.
`It is an object of the invention to provide a data exchange
`system of the kind set forth in which the power consumption
`in the fixed station is lower and which can be flexibly used
`for various applications.
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`SUMMARY OF THE INVENTION
`This is achieved in accordance with the invention by that
`the data carrier is provided with an oscillator which can be
`operated as desired by the energy source, via a switch, and
`which feeds the means in the data carrier for the wireless
`connection during operation, the fixed station comprising
`means for receiving high-frequency energy from the data
`carrier in order to start the transmission of high-frequency
`energy in the fixed station.
`Thus, in accordance with the invention neither the data
`carrier nor the fixed station is operated continually, but
`instead the data carrier can be operated in the active mode,
`preferably by a manually operated switch, so that in turn the
`fixed station is activated and transmits a high-frequency
`electromagnetic field whereby the data carrier is also sup
`plied with energy so that it can quickly terminate its active
`mode of operation. Consequently, the energy source in the
`data carrier is loaded only briefly, and only if necessary, and
`also in the fixed station energy is spent only if a data
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`possible states only, i.e. feeding the oscillator or charging via
`the energy supply.
`
`BRIEF DESCRIPTION OF THE DRAWING
`Examples of embodiments of the invention will be
`described in detail hereinafter with reference to the drawing.
`Therein:
`FIG. 1 shows a block diagram of a data exchange system
`in accordance with the invention, comprising a data carrier
`and a fixed station, and
`FIG. 2 shows a modification of a part of the data carrier.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`FIG. 1 shows the block diagram of a data carrier 1 and a
`fixed station 2. The taam carrier 1 comprises a coil 20 and
`a capacitor 22 which together constitute a resonant circuit.
`This resonant circuit is connected, via the leads 21 and 23,
`to a rectifier circuit 12 which generates, from the voltage
`arising in the resonant circuit when the coil 20 receives a
`high-frequency magnetic field, at least one direct voltage on
`a lead 13, which direct voltage supplies the data processing
`circuit 16. This circuit 16 comprises at least one memory, but
`often also several memories and a microprocessor which,
`however, are not shown separately for the sake of clarity.
`The circuit 16 is also connected, via the leads 21 and 23, to
`the resonant circuit 20, 22 and transfers the data to be
`transmitted preferably in that the resonant circuit is damped
`as function of the binary value of the data.
`The fixed station 2 also comprises a resonant circuit
`which consists of a coil 30 and a capacitor 32 and which is
`connected to an oscillator 34 via leads 31 and 33. This
`oscillator 34 is designed for a high performance and receives
`its energy supply, via a lead 41, and also data to be
`transmitted, via a lead 39, from a processing device 38; this
`is customarily a computer which also receives its energy
`supply via the lead 41. The data received via the lead 39 are
`Supplied, for example by frequency modulation or phase
`modulation, in the oscillator 34 to the resonant circuit 30, 32.
`The leads 31 and 33 from the resonant circuit are also
`connected to a receiver device 36 which detects and regen
`erates the data modulated by the data carrier 1 and supplies
`them to the computer 38.
`The elements described thus tar correspond to a conven
`tional data exchange system with a data carrier 1 which is
`operated in the passive mode, i.e. a data carrier which can
`transmit data to the fixed station 2 only if the latter transmits
`a high-frequency electromagnetic field and if the latter field
`is received with sufficient strength by the coil 20 of the data
`carrier 1. In the system shown in FIG. 1 there are addition
`ally provided an energy source 10 and an oscillator 18 which
`is also connected to the resonant circuit 20, 22 by way of the
`leads 21 and 23. When a user of the data carrier 1 wishes to
`commence a data exchange with a fixed station 2 which is
`in the rest state and which does not transmit a high
`frequency magnetic field, a switch 28 in the data carrier 1 is
`closed so that the oscillator 18isted by the energy source 10,
`via the lead 11 and the switch 24, and triggers the resonant
`circuit 20, 22 which constitutes a or the frequency-deter
`mining part of the oscillator 18. The voltage thus arising in
`the resonant circuit 20, 22 is processed in the rectifier circuit
`12 in the same way as a voltage in the resonant circuit 20,
`22 which is produced by a high-frequency magnetic field
`from a fixed station. Thus, on the lead 13 there is formed a
`direct voltage which triggers the circuit 16 to supply data
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`which are modulated in a customary manner on the oscil
`lation produced therein, for example by damping the reso
`nant circuits 20, 22.
`The coil 30 in the fixed station 2 receives the signal
`transmitted by the data carrier 1 and generates a correspond
`ing voltage on the leads 31 and 33, which voltage is
`evaluated by the receiver circuit 36 because this circuit 36 is
`continually kept in operation, via the lead 35, by an energy
`source 40 in the fixed station. Such a receiver circuit 36
`customarily requires only a very small amount of electric
`energy. As soon as the receiver circuit 36 detects a signal
`voltage on the leads 31 and 33, it activates a switch 42 so
`that the lead 41 is also connected to the energy source 40 and
`the computer 38 and the oscillator 34 are switched on. The
`fixed station 2 then actively generates a high-frequency
`magnetic field which is taken up by the data carrier 1 and
`applied to the rectifier circuit 12. When the high-frequency
`power taken up by the data carrier 1 exceeds that produced
`by the oscillator 18 in the resonant circuit 20, 22 by a
`sufficient amount, the voltage oil the lead 13 is, for example,
`made to increase. A detection circuit 14 which is also
`controlled by this voltage and which detects this power
`increase, or this higher power applied to the rectifier circuit
`12, then opens the switch 24 so that the oscillator 18 is
`switched off. The data carrier 1 then operates only in the
`passive mode on the basis of the high-frequency energy
`transmitted by the fixed station 2.
`The rectifier circuit 12 may also comprise a stabilization
`circuit or voltage control circuit for the voltage oil the lead
`13, and the detection circuit 14 may also be controlled by the
`stabilization or control signal from the rectifier circuit 12.
`When the energy received by the coil 20 in the data carrier
`1 is sufficiently high, the detection circuit 14 applies, via a
`lead 17, the voltage generated on the lead 13, or a voltage
`derived therefrom, to a supply output 15 which is connected
`to the energy source 10, via the lead 11, and which thus
`charges this source. As a result, the loss of energy occurring
`in the energy source 10 during the initial active mode of
`operation of the data carrier 1 call be readily compensated
`for again.
`In the circuit shown in FIG. 1 the detection circuit 14 can
`respond to two different values of the high-frequency power
`received in that the switch 24 is opened for the first power
`value and that in the presence of a second, higher power
`value a voltage is applied to the supply output 15. However,
`it is alternatively possible to choose the two power values to
`be equal, so that at the same time the switch 24 is opened and
`a voltage is applied to the supply output 15.
`FIG. 2 shows a slightly different implementation of the
`switching over of the energy source 10 from supplying the
`oscillator 18 to charging, notably when the voltage on the
`lead 13 corresponds to the voltage of the energy source 10.
`To this end, the energy source 10 is connected, via the lead
`11, to a switch 50 which is controlled by the detection circuit
`14. When a sufficiently high high-frequency power is
`received in the data carrier, the detection circuit 14 controls
`the switch 50 so that the lead 11 of the energy source 10 is
`connected instead to the lead 13, so that automatically the
`oscillator in the data carrier is switched off and the energy
`source 10 is charged.
`What is claimed is:
`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 compris
`ing:
`a fixed station, wherein said fixed station comprises
`means for establishing a wireless connection in a first
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`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
`carrier comprises
`(i) an electric circuit for providing data to be transmit
`ted 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 operat
`ing 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 operat
`ing in the second mode, actively transmitting, via the
`wireless connection establishing means of said fixed
`station, high-frequency energy and data for subse
`quent receipt thereof by said data carrier via the
`wireless connection establishing means of said data
`carrier, said data carder further comprising
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`(vii) detection means, responsive to the high-frequency
`energy received from said fixed station, for switch
`ing 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-deter
`mining 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.
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`Ex.1005
`APPLE INC. / Page 5 of 5
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