(19)
(11)EP 3 493 097 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
24.03.2021 Bulletin 2021/12

(21)Application number: 17204337.4

(22)Date of filing:  29.11.2017
(51)International Patent Classification (IPC): 
G06K 7/00(2006.01)
G06K 19/07(2006.01)

(54)

METHOD FOR SUPPLYING ENERGY WIRELESSLY BY MEANS OF RADIO FREQUENCY IDENTIFICATION, RFID, AND RFID SYSTEM

VERFAHREN ZUR DRAHTLOSEN BEREITSTELLUNG VON ENERGIE MITTELS FUNKFREQUENZIDENTIFIKATION (RFID) UND RFID-SYSTEM

PROCÉDÉ PERMETTANT DE FOURNIR DE L'ÉNERGIE SANS FIL AU MOYEN D'UNE IDENTIFICATION DE FRÉQUENCE RADIO, RFID ET SYSTÈME RFID


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(43)Date of publication of application:
05.06.2019 Bulletin 2019/23

(73)Proprietor: ams AG
8141 Premstätten (AT)

(72)Inventor:
  • Manzi, Giuliano
    5656 AE Eindhoven (NL)

(74)Representative: Epping - Hermann - Fischer 
Patentanwaltsgesellschaft mbH Schloßschmidstraße 5
80639 München
80639 München (DE)


(56)References cited: : 
EP-A2- 1 069 526
WO-A2-01/95242
US-A1- 2015 186 693
EP-A2- 3 182 609
US-A1- 2011 285 511
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] The field of this application concerns Radio Frequency Identification, RFID, especially the wireless supply of energy using RFID. The energy is supplied to a sensor, for example.

    [0002] Recently, an increasing interest in sensing solutions has occurred and a trend toward pervasive sensing can be observed. Many sensor solutions are integrated or embedded into electronic devices, cars, wearables, garments, small objects, plants, field, houses and the like. At the same time an increase in wireless interfaces can be observed. The so-called pervasive electromagnetism discipline is getting more and more attention. Said pervasive electromagnetic aims at providing the physical layer of the emerging Internet of Things that enables the Internet to get into the real world of physical objects.

    [0003] A device providing sensing capability is known as a sensor. In case said sensor is equipped with an electronic label identifying the sensor is turned into a digital entity readable from remote by means of RFID. Such device is called a wireless sensor. In fact, RFID technology may be regarded as the natural support or medium to achieve remote identification and communication with a resulting sensor label or sensor tag.

    [0004] Neither active, passive nor semi-passive RFID based wireless sensors will be able to keep energized during their entire life cycle with a very small battery or any other kind of energy storage means. In view of a cost effective and easily deployable solution, wireless sensors are supposed to require very limited maintenance during their entire life cycle, ideally only the installation work. The life cycle of wireless sensors can be several years, up to ten or more in the case of a wireless sensor embedded in the concrete structure of a building, for example. Consequently, one of the main issues in the application of wireless sensors is their power management. State of the art wireless sensor systems require relatively expensive maintenance for battery replacement and/or maintenance of the recharging system as well as the power supply system via power networks.

    [0005] Known solutions for wireless charging of such sensors are focusing on the rectification of an incoming radio-frequency, RF, signal which can be modulated or unmodulated, to a direct current, DC, voltage assuming that the incoming signal is a constant wave at a certain frequency. Unfortunately this last point is not how communication systems using the Industrial, Medical, Scientific, ISM, frequency band according to defined standards communicate. Most ISM based systems, like RFID, use some form of amplitude-shift keying, ASK, like e.g. phase-reversal, PR-ASK, when transmitting data by means of RF signals between reader and tag. The efficiency of converting these alternate current, AC, RF signals to DC signals is limited by the level of modulation used during the data transmission. Therein, typical amplitudes vary from 100% to 0-10%. Consequently, if the signal level is below 10%, nearly no conversion occurs and the system is unable to produce the necessary DC voltage.

    [0006] WO 01/95242 A2 refers to a remote communication method which includes receiving an energy signal and converting said energy signal into a supply voltage; receiving a first data signal at a frequency that is different than the frequency of the energy signal; and transforming the first data signal in accordance with a predetermined transformation scheme into a second data signal and transmitting the second data signal, all using the supply voltage converted from the energy signal.

    [0007] EP 3182609 A2 presents a wireless data communication device and a corresponding method.

    [0008] US 2015/186693 A1 refers to systems and methods for RFID localization.

    [0009] It is therefore an object of the present disclosure to provide a cost effective and efficient possibility for energizing wireless sensors.

    [0010] The object is achieved by the subject matter of the independent claim. Embodiments and developments are defined in the dependent claims.

    [0011] The definitions as described above also apply to the following description unless stated otherwise.

    [0012] In one embodiment a method for supplying energy wirelessly by means of RFID comprises the following steps:

    sending by an RFID reader device a request message to at least one RFID tag device,

    receiving by the at least one RFID tag device while being in an RFIP operation mode the request message,

    sending by the at least one RFID tag device while being in the RFIP operation mode an answer message to the RFID reader device and changing by the at least one RFID tag device its state into a higher power mode,

    receiving by the RFID reader device the answer message, sending by the RFID reader device an energizing signal having an unmodulated constant wave at a predefined frequency during an adjustable amount of time,

    receiving by the at least one RFID device the energizing signal, converting said signal into energy and using the energy by the at least one RFID tag device,

    changing by the at least one RFID tag device its state into the RFID operation mode at the end of the adjustable amount of time. Therein the request message comprises a first command which causes the at least one RFID tag device to change its state into the higher power mode. The request message further comprises information on the adjustable amount of time for the sending of the energizing signal.



    [0013] By means of the unmodulated constant wave which is transmitted with the energizing signal from the reader device and is converted in the at least one tag device into energy during the high power mode, the efficiency of the conversion is higher compared to state of the art solutions. Consequently, the amount of energy generated in that way is higher. The method is based on an RFID system. It reuses the physical layer of said RFID system. Therefore, the proposed method enables a cost-effective wireless energizing of sensors and wireless sensors.

    [0014] The RFID communication which is employed in the defined method is for instance of the type ultra-high frequency, UHF, RFID, and conforms to the related standards as defined in, for example, the ETSI EN 302 208-1 V1.4.1 as of 2011/11. The generated energy comprises a DC voltage, for example. The RFID reader device and the RFID tag device are prepared to conform to the related standards. The RFID reader device consequently fulfils the requirements of a reader or interrogator defined in said standards interrogator, while The RFID tag device fulfils the requirements of a tag or transponder specified in said standards.

    [0015] By means of the request message sent by the RFID reader device, a dedicated state is established in the at least one RFID tag device, i.e. the higher power mode. In this high power mode, the energizing signal is efficiently converted into energy. At the end of the adjustable amount of time during which the energy is generated, the at least one RFID tag device changes its state back into the RFID operation mode. In this mode messages are transmitted between the RFID reader device and the at least one RFID tag device according to the relevant standards as known by those skilled in the art.

    [0016] Upon receipt of the request message the RFID tag device changes its state or operation mode from RFID operation mode to high power operation mode. The request message conforms, for example, to the request message as defined in the UHF RFID standards.

    [0017] By means of the request message the at least one RFID tag device is informed about the amount of time during which it should stay in the high power mode and convert energy from the energizing signal. Said amount of time is adjustable, for example, in order to fulfill regional regulatory requirements and standard requirements. For instance, in the European region, said adjustable amount of time is, for instance, set to four seconds as defined in the above mentioned ETSI standard and limited by clause 8.6.3. In FCC regions, e.g. the US, the adjustable amount of time is set to a multiple of 0.4 seconds due to the channel hopping as defined in §15.247.(i). The duration during which the constant wave is transmitted can consequently be adapted according to regulation or use requirements.

    [0018] During the high power mode no communication using field modulation shall occur between the RFID reader and tag devices.

    [0019] In a development the request message comprises a second command which causes the at least one RFID tag device to perform an operation on a sensor which can be connected to the RFID tag device. In this case the method further comprises the step of performing by the at least one RFID device said operation according to the second command.

    [0020] By the second command the at least one RFID tag device is caused to perform the operation defined in the second command on a sensor which can be connected to the RFID tag device. Said operation may, for instance, amount to read data from the connectable sensor via one of the standard interfaces, for example, serial peripheral interface, SPI, or inter-integrated circuit, I2C.

    [0021] In a development the answer message comprises an acknowledgement signifying successful receipt of the request message.

    [0022] In a development using the energy by the at least one RFID tag device comprises storing the energy in an energy storage device which can be connected to the at least one RFID tag device and/or providing the energy to a sensor which can be connected to the RFID tag device.

    [0023] The energy storage device which is connectable to the RFID tag device, for example, comprises a capacitor. Additionally or alternatively to the storing of the energy in the energy storage device, the energy is provided to a connectable sensor. In case the sensor is connected to the RFID tag device, the resulting combination represents a wireless sensor. Usage of the energy is not only restricted to the high power mode. In fact, the energy generated during the high power mode can also be used during the RFID operation mode.

    [0024] In a development the sending by the RFID reader device of the energizing signal comprises changing a transmission mode of the RFID reader device into a constant wave mode, turning on an RFID carrier signal in the RFID reader device and emitting said carrier signal representing the energizing signal.

    [0025] The UHF RFID standard defines several transmission modes, one of which is the constant wave mode which is used in the currently defined method for transmitting the energizing signal.

    [0026] In a development the converting of the energizing signal into energy comprises rectifying the energizing signal and providing a direct current signal from this rectifying.

    [0027] For the rectification of the energizing signal well-known rectifiers based e.g. on semiconductor diodes are employed. The direct current signal, which is generated by the described energy harvesting or energy scavenging during the high power mode, comprises a DC voltage, for example.

    [0028] In a development during the sending by the RFID reader device of the energizing signal, the method further comprises sending by the RFID reader device another message and receiving said another message by the at least one RFID tag device.

    [0029] Said another message comprises a command to be transmitted from the reader device to the tag device which enables, for example, handling of a special load condition or special environment condition like the presence of a very high electromagnetic field.

    [0030] In another development, the method further comprises during converting the energizing signal into energy dynamically adapting an amount of said energy to a load situation present with the at least one RFID tag device and/or to a load situation present within a sensor which can be connected to the RFID tag device.

    [0031] In order to maximize efficiency and to be compliant with worldwide emission regulations, the generation of energy in the high power mode adjusts to the current load situation within the RFID tag device or within the connectable sensor. The proposed method is consequently self-regulating. It also minimizes the disturbance on other communication systems using the ISM band by enabling easy adaptation of the duration of the energizing signal to local regulations in time and frequency division or time and frequency hopping based RFID systems.

    [0032] In one embodiment an RFID system has an RFID reader device and at least one RFID tag device. The RFID system is prepared to execute the method as described and defined above.

    [0033] The RFID reader device is consequently prepared to send the request message, to receive the answer message and send the energizing signal during the adjustable amount of time as detailed above.

    [0034] The at least one RFID tag device is prepared to receive the request message, to send the answer message and change its state into the high power mode, to receive the energizing signal for the adjustable amount of time, to convert said signal into energy and use the energy and finally to change its state back into the RFID operation mode.

    [0035] Said system enables a solution for energizing a wireless sensor, i.e. a sensor which can be connected to the at least one RFID device and thereby becoming a wireless sensor, which solution is low cost and very efficient in scavenging energy.

    [0036] In case the system has two or more RFID tag devices communicating with the RFID reader device, the system also offers the possibility for energizing two or more RFID tag devices, thereby energizing sensors which can be coupled to the RFID tag devices.

    [0037] In a development the RFID tag device comprises an antenna, an analog frontend circuit which is connected to the antenna, a power management component which is connected to the analog frontend circuit and a logic circuit. The analog frontend circuit is enabled to receive the request message and the energizing signal sent by the RFID reader device and to send the answer message to the RFID reader device by means of the antenna. The logic circuit is coupled to the analog frontend circuit and to the power management component for respective control thereof. The power management component has a rectifier circuit which is prepared to rectify the energizing signal and therefrom provide the energy.

    [0038] When starting out from a state of the art RFID tag device, for example a UHF RFID tag device, the analog frontend circuit is adapted to pass the energizing signal received from the RFID reader device to the power management component with its rectifier circuit. Said rectifier circuit is active at least during the high power mode and during the adjustable amount of time rectifies the incoming constant wave as transmitted by the reader device, thereby converting the RF field into a DC voltage and therefrom provide the energy. A rectification component which is present in state of the art RFID tag devices and is employed for generation of energy during the RFID operation mode shall be disabled during the high power mode for higher efficiency of harvesting of energy.

    [0039] In a development the power management component of the RFID tag device further comprises a charge pump circuit which is connected to the rectifier circuit and is prepared to receive the energy from the rectifier circuit, to convert said energy to a higher level and therefrom provide the energy at the higher level.

    [0040] Optionally, the charge pump circuit is employed to pump the DC signal derived from the energizing signal in the rectifier component to a higher level. In an exemplary implementation the rectifier component provides the energy in the form of a DC signal at 1.8 V. The charge pump circuit pumps the signal to a level of 3 V.

    [0041] In a development the power management component of the RFID tag device further comprises a power mode select component which is adapted to configure the analog frontend circuit for the higher power mode or for the RFID operation mode under control of the logic circuit.

    [0042] The power mode select component configures, for example, the state of modulation transistors employed in modulator and/or demodulator components of the analog frontend circuit for optimizing the amount of energy which is generated during the high power mode.

    [0043] In a development the power management component of the RFID tag device further comprises a checking component. Said checking component is prepared to measure an amount of power needed by the RFID tag device and/or an amount of power needed by a sensor which can be connected to the RFID tag device and therefrom provides a status signal to the logic circuit. The logic circuit is prepared to configure the power management component according to the status signal.

    [0044] By means of the status signal the logic circuit determines, for example, if the charge pump circuit shall be activated in order to provide the energy at a higher level. Consequently, the generation of energy in the high power mode is adapted to the needs of the RFID tag device or a sensor which can be connected to it. In other words, the power management component is adjusted to a load present within the RFID tag device and/or at the connectable sensor, thereby realizing a self-regulating generation of energy. The conversion efficiency is enhanced.

    [0045] The analog frontend circuit is strongly nonlinear with its input impedance being dependent on an RF input level, i.e. level of the RF field at its antenna and on the load condition. In order to achieve best performances in each condition the power management component adapts to the current load condition and to the input power level.

    [0046] In an exemplary implementation of the RFID tag device, it can be configured how often the power management component provides the status signal.

    [0047] The text below explains the proposed method and corresponding system in detail using exemplary embodiments with reference to the drawings. Components and circuit elements that are functionally identical or have the identical effect bear identical reference numbers. In so far as circuit parts or components correspond to one another in function, a description of them will not be repeated in each of the following figures.
    Figure 1
    shows an embodiment example of the proposed method;
    Figure 2
    shows a first embodiment example of an RFID tag device to be employed in the proposed system;
    Figure 3
    shows a second embodiment example of an RFID tag device to be employed in the proposed system.


    [0048] Figure 1 shows an embodiment example of the proposed method. The method is depicted with relation to time t. The first line shows operation modes of an RFID tag device. The second line depicts a message flow at an RFID reader device 10. The third line shows a message flow at the RFID tag device 20. The fourth line depicts optional operation at the RFID tag device 20 using SPI/I2C for interfacing to a connectable sensor.

    [0049] The method starts out with the RFID tag device 20 being in an RFID operation mode. At point in time t0 the RFID reader device 10 sends a request message 100 to the RFID tag device 20. Upon receipt of the request message 100 the RFID tag device 20 sends an answer message 110 back to the RFID reader device 10 at point in time t0'. Subsequently, at point in time t1 the RFID tag device 20 sets its operation mode or its state into a high power mode as indicated in the first line. Then, the RFID reader device 10 starts emitting an energizing signal 120 which comprises an unmodulated constant wave at a predefined frequency. The energizing signal 120 is sent for an adjustable amount of time between the point in time t1 and a point in time t2. During the point in times t1 and t2 the RFID tag device 20 receives the energizing signal 120, converts said signal 120 into energy and uses said energy. At the end of the adjustable amount of time at point in time t2 the RFID tag device 20 changes its state or mode of operation back into the RFID operation mode enabling state of the art RFID communication according to well-known standards, e.g. UHF RFID.

    [0050] The above-described request message 100 comprises a first command which causes the RFID tag device 20 to change its state from RFID operation mode into high power mode. The request message 100 further comprises information on the adjustable amount of time during which the energizing signal 120 is emitted by the RFID reader device 10.

    [0051] Figure 1 shows the method being executed by a system comprising one RFID reader device 10 and one RFID tag device 20. In further developments it is of course possible that the system has two or more RFID tag devices which receive the request message 100 simultaneously, turn on the high power mode and harvest energy from the energizing signal 120 concurrently.

    [0052] Optionally, the request message 100 comprises a second command which causes the RFID tag device 20 to perform an operation on a sensor which can be connected to the RFID tag device 20 by means of an SPI or I2C interface. For example, the second command may contain an SPI or I2C read command and an indication of an amount of time for delaying execution of said second command. According to this option the RFID tag device 20 may perform the requested SPI or I2C read operation 130 according to the second command at point in time t1' and store said data in its own memory e.g. an EEPROM. In the depicted example said operation 130 is delayed until point in time t1'. Data may be read from a connectable sensor via SPI or I2C during the high power mode. After finishing emission of the energizing signal 120, the RFID reader device 10 sends a read request message 140 comprising a read memory command shortly after point in time t2. In response to the request message 140, the RFID tag device 20 transmits the SPI or I2C data which had been meanwhile stored in its memory, e.g. EEPROM, by means of answer message 150.

    [0053] Figure 2 shows a first embodiment example of an RFID tag device to be employed in the proposed system. The RFID tag device 20 comprises an antenna 21, an analog frontend circuit 22, a power management component 23, and a logic circuit 24. Optionally, the tag device 20 also has a memory component 25. The antenna 21 is connected to the analog frontend circuit 22 which in turn is connected to the power management component 23. The logic circuit 24 is coupled to the analog frontend circuit 22, the power management component 23 and optionally to the memory component 25 for respective control of said components.

    [0054] Figure 2 also shows a sensor S which can be connected to respective ports of the RFID tag device 20. The sensor S is connected to the RFID tag device 20 via SPI/I2C for data and command exchange and via a second interface IF2 for supply of energy. Also, an energy storage device, in the form of a capacitor C, is shown which can be connected to the RFID tag device 20 in addition to the sensor S.

    [0055] The antenna 21 is suitable for communication in the ISM band. For operation during the RFID operation mode, the RFID tag device 20 has the required components as known to those skilled in the art, said components being depicted in an exemplary manner without making a claim to be complete. The analog frontend circuit 22 for operation in the high power and in the RFID operation mode may have an electrostatic discharge component 222. Furthermore, for operation in the RFID operation mode the analog frontend circuit 22 may further have a limiter component 223, a modulator component 224, a demodulator component 225 and a low power rectifier 226. The limiter component 223, the modulator component 224, the demodulator component 225 and the low power rectifier 226 together form a signal path for signals occurring during the RFID operation mode. This means that request messages received from an RFID reader device which conform to, for example, the UHF RFID standard, and corresponding answer messages are handled in this signal path. The low power rectifier 226 is implemented by a multi-stage rectifier, for example.

    [0056] In addition to an analog frontend circuit as known to those skilled in the art, the depicted analog frontend circuit 22 comprises a frontend mode select component 221 which selectively activates the just described signal path used during the RFID operation mode or another signal path to be detailed in the following which is activated during the high power mode under control of the logic circuit 24. During the high power mode the frontend mode select component 221 disables the state of the art signal path of the RFID operation mode and passes the signal received via the antenna 21 directly to the power management component 23, i.e. the energizing signal is directly passed on to a rectifier circuit 231 of the power management component 23.

    [0057] Optionally, the analog frontend circuit 22 comprises a demodulator 227 which enables demodulation of commands sent by the RFID reader device during the high power mode.

    [0058] The power management component 23 comprises the rectifier circuit 231, a charge pump circuit 232, a power mode select component 233 and a checking component 234. The power mode select component 233 is coupled to the rectifier circuit 231 and to the low power rectifier 226. The power mode select component 233 is adapted to configure the analog frontend circuit 22 for the high power mode or the RFID operation mode under control of the logic circuit 24. In other words, the power mode select component 233 either activates the rectifier circuit 231 during the high power mode or it activates the low power rectifier 226 during normal RFID operation mode. Consequently, during high power mode the energizing signal is received by the antenna 21, passed through the analog frontend 22 and gets rectified in the high power rectifier circuit 231. The rectifier circuit 231 is implemented by a highly efficient single rectification stage, for example. The energy converted from this rectifying process is provided, for instance in the form of a DC voltage VDC. An exemplary level of said DC voltage VDC may be 1.8 V. Said energy in the form of the voltage VDC is provided either to the connectable capacitor C or to the connectable sensor S. Optionally, the charge pump circuit 232 pumps the level of the voltage VDC to a higher level, for instance 3 V and therefrom provides a higher level voltage VDC3. The checking component 234 is prepared to measure an amount of power needed by the RFID tag device 20 and/or an amount of power needed by the sensor S and therefrom provide a status signal S23 to the logic circuit 24. Depending on the status signal S23 the logic circuit 24 configures respective switches in order to enable the charge pump circuit 232 and provide the high level voltage VDC3 to the sensor S or capacitor C or to disable the charge pump circuit 232 and directly provide the voltage VDC to capacitor C or sensor S. For providing the status signal S23 the checking component 234 may use a reference signal Sref for comparison to the measured amount of power needed. Additionally to providing energy in the form of the voltage VDC or VDC3 to the sensor S, said energy is supplied to the capacitor C and stored there.

    [0059] The memory component 25 comprises state of the art memory, for instance an EEPROM. The logic circuit 24 comprises in addition to components required for implementing the control function in the proposed method off the shelf, known components for realizing interface operation and UHF RFID protocol in a standard compliant manner. For example, an SPI/I2C master/slave component is provided and an EPC Gen2 controller for standard compliant protocol handling.

    [0060] Figure 3 shows a second embodiment example of an RFID tag device to be employed in the proposed system. The embodiment depicted in Figure 3 coincides with the embodiment depicted in Figure 2 except for the implementation of the analog frontend circuit 22. In Figure 3 the analog frontend circuit 22 is implemented with two separate antenna connections for a low power frontend 22a and a high power frontend 22b. The limiter component 223, the modulator component 224, the demodulator component 225, and the low power rectifier 226 form the lower power frontend 22a. The high power frontend 22b has the demodulator 227 and a high power limiter 228. The logic circuit 24 either activates the lower power frontend 22a during the RFID operation mode or it activates the high power fronted 22b during the high power mode. The two frontend parts 22a, 22b have separate connections, as shown in Figure 3, to the same antenna 21.

    Reference list



    [0061] 
    100, 110, 120
    message
    10
    reader device
    20
    tag device
    t1, t1', t2
    point in time
    t0, t0', t2'
    point in time
    21
    antenna
    22
    analog front end circuit
    23
    power management component
    24
    logic circuit
    231
    rectifier circuit
    232
    charge pump circuit
    233
    power mode select component
    234
    checking component
    221
    front end mode select component
    25
    memory component
    222
    ESD component
    223
    limiter component
    224, 225
    modulator/demodulator component
    226
    low power rectifier
    227
    demodulator
    228
    high power limiter
    22a, 22b
    front end
    S23
    status signal
    Sref
    reference signal
    VDC, VDC3
    voltage



    Claims

    1. Method for supplying energy wirelessly by means of Radio Frequency Identification, RFID, comprising the steps of

    - sending by an RFID reader device (10) a request message (100) to at least one RFID tag device (20),

    - receiving by the at least one RFID tag device (20) while being in an RFID operation mode the request message (100),

    - sending by the at least one RFID tag device (20) while being in the RFID operation mode an answer message (110) to the RFID reader device (10) and changing by the at least one RFID tag device (20) its state into a high power mode,

    - receiving by the RFID reader device (10) the answer message (110),

    - sending by the RFID reader device (10) an energizing signal (120) having an unmodulated constant wave at a predefined frequency during an adjustable amount of time,

    - receiving by the at least one RFID tag device (20) the energizing signal (120), converting said signal into energy and using the energy by the at least one RFID tag device,

    - changing by the at least one RFID tag device (20) its state into the RFID operation mode at the end of the adjustable amount of time,

    characterized in that
    the request message (100) comprises a first command which causes the at least one RFID tag device (20) to change its state into the high power mode, and
    wherein the request message (100) further comprises information on the adjustable amount of time for the sending of the energizing signal (120).
     
    2. Method according to claim 1,
    wherein the request message (100) comprises a second command which causes the at least one RFID tag device (20) to perform an operation (140) on a sensor (S) which can be connected to the RFID tag device (20), and wherein the method further comprises the step of performing by the at least one RFID tag device (20) the operation (140) according to the second command.
     
    3. Method according to claim 1 or 2,
    wherein the answer message (110) comprises an acknowledgement signifying successful receipt of the request message.
     
    4. Method according to any one of claims 1 to 3,
    wherein using the energy by the at least one RFID tag device (20) comprises storing the energy in an energy storage device (C) which can be connected to the at least one RFID tag device (20) and/or providing the energy to a sensor (S) which can be connected to the RFID tag device (20).
     
    5. Method according to any one of claims 1 to 4,
    wherein the sending by the RFID reader device (10) the energizing signal (120) comprises changing a transmission mode of the RFID reader device into a constant wave mode, turning on an RFID carrier signal in the RFID reader device (10) and emitting said carrier signal representing the energizing signal (120).
     
    6. Method according to any one of claims 1 to 5,
    wherein the converting the energizing signal (120) into energy comprises rectifying the energizing signal (120) and providing a direct current signal (VDC) from this rectifying.
     
    7. Method according to any one of claims 1 to 6,
    wherein during the sending by the RFID reader device (10) of the energizing signal (120) the method further comprises sending by the RFID reader device (10) another message and receiving said another message by the at least one RFID tag device (20).
     
    8. Method according to any one of claims 1 to 7,
    further comprising during converting the energizing signal (120) into energy, dynamically adapting an amount of said energy to a load situation present within the RFID tag device (20) and/or to a load situation present within a sensor (S) which can be connected to the RFID tag device (20).
     
    9. RFID system having an RFID reader device (10) and at least one RFID tag device (20), wherein the RFID system is adapted to execute the method according to one of claims 1 to 8.
     
    10. RFID system according to claim 9,
    wherein the RFID tag device (20) comprises
    an antenna (21),
    an analog front end circuit (22) which is connected to the antenna (21) and is enabled to receive the request message (100) and the energizing signal (120) sent by the RFID reader device (10) and to send the answer message (110) to the RFID reader device (10) by means of the antenna,
    a power management component (23) which is connected to the analog front end circuit (22), and
    a logic circuit (24) which is coupled to the analog front end circuit (22) and the power management component (23) for respective control thereof,
    wherein the power management component (23) has a rectifier circuit (231) which is prepared to rectify the energizing signal (120) and therefrom provide the energy.
     
    11. RFID system according to claim 10,
    wherein the power management component (23) of the RFID tag device (20) further comprises a charge pump circuit (232) which is connected to the rectifier circuit (231) and is prepared to receive the energy from the rectifier circuit (231), convert said energy to a higher level and therefrom provide the energy at the higher level.
     
    12. RFID system according to claim 10 or 11,
    wherein the power management component (23) of the RFID tag device (20) further comprises a power mode select component (233) which is adapted to configure the analog front end circuit (22) for the high power mode or the RFID operation mode under control of the logic circuit (24).
     
    13. RFID system according to any of claims 10 to 12,
    wherein the power management component (23) of the RFID tag device (20) further comprises a checking component (234) which is prepared to measure an amount of power needed by the RFID tag device (20) and/or an amount of power needed by a sensor (S) which can be connected to the RFID tag device (20) and therefrom provide a status signal to the logic circuit (24),
    and wherein the logic circuit (24) is prepared to configure the power management component (23) according to the status signal.
     


    Ansprüche

    1. Verfahren zum drahtlosen Zuführen von Energie mittels Hochfrequenzidentifikation, RFID, die Schritte umfassend:

    - Senden einer Anforderungsnachricht (100) durch eine RFID-Lesevorrichtung (10) an mindestens eine RFID-Etikettenvorrichtung (20),

    - Empfangen der Anforderungsnachricht (100) durch die mindestens eine RFID-Etikettenvorrichtung (20), während sie sich in einem RFID-Betriebsmodus befindet,

    - Senden einer Antwortnachricht (110) durch die mindestens eine RFID-Etikettenvorrichtung (20), während sie sich im RFID-Betriebsmodus befindet, an die RFID-Lesevorrichtung (10), und Umschalten, durch die mindestens eine RFID-Etikettenvorrichtung (20), ihres Zustands in einen Hochleistungsmodus,

    - Empfangen der Antwortnachricht (110) durch die RFID-Lesevorrichtung (10),

    - Senden, durch die RFID-Lesevorrichtung (10), eines Energieversorgungssignals (120) mit einer nichtmodulierten konstanten Welle bei einer vordefinierten Frequenz während einer einstellbaren Zeitspanne,

    - Empfangen des Energieversorgungssignals (120) durch die mindestens eine RFID-Etikettenvorrichtung (20), Umwandeln des Signals in Energie und Verwenden der Energie durch die mindestens eine RFID-Etikettenvorrichtung,

    - Umschalten, durch die mindestens eine RFID-Etikettenvorrichtung (20), ihres Zustands in den RFID-Betriebsmodus am Ende der einstellbaren Zeitspanne,

    dadurch gekennzeichnet, dass
    die Anforderungsnachricht (100) einen ersten Befehl umfasst, der die mindestens eine RFID-Etikettenvorrichtung (20) dazu bringt, ihren Zustand in den Hochleistungsmodus umzuschalten, und
    wobei die Anforderungsnachricht (100) darüber hinaus Informationen über die einstellbare Zeitspanne zum Senden des Energieversorgungssignals (120) umfasst.
     
    2. Verfahren nach Anspruch 1,
    wobei die Anforderungsnachricht (100) einen zweiten Befehl aufweist, der die mindestens eine RFID-Etikettenvorrichtung (20) dazu bringt, einen Vorgang (140) an einem Sensor (S) vorzunehmen, der mit der RFID-Etikettenvorrichtung (20) verbunden sein kann, und wobei das Verfahren darüber hinaus den Schritt umfasst, dass die mindestens eine RFID-Etikettenvorrichtung (20) den Vorgang (140) gemäß dem zweiten Befehl durchführt.
     
    3. Verfahren nach Anspruch 1 oder 2,
    wobei die Antwortnachricht (110) eine Bestätigung umfasst, die den erfolgreichen Empfang der Anforderungsnachricht anzeigt.
     
    4. Verfahren nach einem der Ansprüche 1 bis 3,
    wobei das Verwenden der Energie durch die mindestens eine RFID-Etikettenvorrichtung (20) umfasst, die Energie in einer Energiespeichervorrichtung (C) zu speichern, die mit der mindestens einen RFID-Etikettenvorrichtung (20) verbunden sein kann, und/oder die Energie einem Sensor (S) bereitzustellen, der mit der RFID-Etikettenvorrichtung (20) verbunden sein kann.
     
    5. Verfahren nach einem der Ansprüche 1 bis 4,
    wobei das Senden des Energieversorgungssignals (120) durch die RFID-Lesevorrichtung (10) umfasst, einen Übertragungsmodus der RFID-Lesevorrichtung in einen Konstantwellenmodus zu ändern, ein RFID-Trägersignal in der RFID-Lesevorrichtung (10) einzuschalten und das Trägersignal, welches das Energieversorgungssignal (120) darstellt, auszusenden.
     
    6. Verfahren nach einem der Ansprüche 1 bis 5,
    wobei das Umwandeln des Energieversorgungssignals (120) in Energie umfasst, das Energieversorgungssignal (120) gleichzurichten und aus dieser Gleichrichtung ein Gleichstromsignal (VDC) bereitzustellen.
     
    7. Verfahren nach einem der Ansprüche 1 bis 6,
    wobei während des Sendens des Energieversorgungssignals (120) durch die RFID-Lesevorrichtung (10) das Verfahren darüber hinaus das Senden einer weiteren Nachricht durch die RFID-Lesevorrichtung (10) und das Empfangen dieser weiteren Nachricht durch die mindestens eine RFID-Etikettenvorrichtung (20) umfasst.
     
    8. Verfahren nach einem der Ansprüche 1 bis 7,
    darüber hinaus umfassend, während des Umwandelns des Energieversorgungssignals (120) in Energie, einen Betrag der Energie dynamisch an eine Lastsituation anzupassen, die in der RFID-Etikettenvorrichtung (20) besteht, und/oder an eine Lastsituation anzupassen, die in einem Sensor (S) besteht, der mit der RFID-Etikettenvorrichtung (20) verbunden sein kann.
     
    9. RFID-System mit einer RFID-Lesevorrichtung (10) und mindestens einer RFID-Etikettenvorrichtung (20), wobei das RFID-System dazu angepasst ist, das Verfahren nach einem der Ansprüche 1 bis 8 auszuführen.
     
    10. RFID-System nach Anspruch 9,
    wobei die RFID-Etikettenvorrichtung (20) aufweist:

    eine Antenne (21),

    eine analoge Front-End-Schaltung (22), die mit der Antenne (21) verbunden und in der Lage ist, die Anforderungsnachricht (100) und das Energieversorgungssignal (120) zu empfangen, die von der RFID-Lesevorrichtung (10) gesendet werden, und die Antwortnachricht (110) mittels der Antenne an die RFID-Lesevorrichtung (10) zu senden,

    eine Leistungsverwaltungskomponente (23), die mit der analogen Front-End-Schaltung (22) verbunden ist, und

    eine Logikschaltung (24), die an die analoge Front-End-Schaltung (22) und die Leistungsverwaltungskomponente (23) zu deren jeweiliger Steuerung angeschlossen ist,

    wobei die Leistungsverwaltungskomponente (23) eine Gleichrichterschaltung (231) aufweist, die dazu vorbereitet ist, das Energieversorgungssignal (120) gleichzurichten und daraus die Energie bereitzustellen.


     
    11. RFID-System nach Anspruch 10,
    wobei die Leistungsverwaltungskomponente (23) der RFID-Etikettenvorrichtung (20) ferner eine Ladungspumpenschaltung (232) aufweist, die mit der Gleichrichterschaltung (231) verbunden und dazu vorbereitet ist, die Energie von der Gleichrichterschaltung (231) zu empfangen, die Energie auf ein höheres Niveau umzuwandeln und daraus die Energie auf dem höheren Niveau bereitzustellen.
     
    12. RFID-System nach Anspruch 10 oder 11,
    wobei die Leistungsverwaltungskomponente (23) der RFID-Etikettenvorrichtung (20) außerdem eine Leistungsmodus-Auswahlkomponente (233) aufweist, die dazu angepasst ist, die analoge Front-End-Schaltung (22) für den Hochleistungsmodus oder den RFID-Betriebsmodus unter der Steuerung der Logikschaltung (24) zu konfigurieren.
     
    13. RFID-System nach einem der Ansprüche 10 bis 12,
    wobei die Leistungsverwaltungskomponente (23) der RFID-Etikettenvorrichtung (20) ferner eine Überprüfungskomponente (234) aufweist, die dazu vorbereitet ist, einen Betrag an Leistung zu messen, der von der RFID-Etikettenvorrichtung (20) benötigt wird, und/oder einen Betrag an Leistung zu messen, der von einem Sensor (3) benötigt wird, der mit der RFID-Etikettenvorrichtung (20) verbunden sein kann, und daraus ein Statussignal an die Logikschaltung (24) bereitzustellen,
    und wobei die Logikschaltung (24) dazu vorbereitet ist, die Leistungsverwaltungskomponente (23) gemäß dem Statussignal zu konfigurieren.
     


    Revendications

    1. Procédé de fourniture d'énergie sans fil par identification par radiofréquence, RFID, comprenant les étapes de

    - envoi par un dispositif lecteur RFID (10) d'un message de demande (100) à au moins un dispositif étiquette RFID (20),

    - réception par l'au moins un dispositif étiquette RFID (20), lorsqu'il est dans un mode de fonctionnement RFID, du message de demande (100),

    - envoi par l'au moins un dispositif étiquette RFID (20), lorsqu'il est dans le mode de fonctionnement RFID, d'un message de réponse (110) au dispositif lecteur RFID (10) et changement par l'au moins un dispositif étiquette RFID (20) de son état en un mode de haute puissance,

    - réception par le dispositif lecteur RFID (10) du message de réponse (110),

    - envoi par le dispositif lecteur RFID (10) d'un signal de mise sous énergie (120) ayant une onde constante non modulée à une fréquence prédéfinie pendant une quantité de temps réglable,

    - réception par l'au moins un dispositif étiquette RFID (20) du signal de mise sous énergie (120), conversion dudit signal en énergie et utilisation de l'énergie par l'au moins un dispositif étiquette RFID,

    - changement par l'au moins un dispositif étiquette RFID (20) de son état en le mode de fonctionnement RFID à la fin de la quantité de temps réglable,

    caractérisé en ce que
    le message de demande (100) comprend une première consigne qui fait changer à l'au moins un dispositif étiquette RFID (20) son état en le mode de haute puissance, et
    sachant que le message de demande (100) comprend en outre des informations sur la quantité de temps réglable pour l'envoi du signal de mise sous énergie (120).
     
    2. Procédé selon la revendication 1,
    sachant que le message de demande (100) comprend une deuxième consigne qui fait exécuter à l'au moins un dispositif étiquette RFID (20) une opération (140) sur un capteur (S) qui peut être connecté au dispositif étiquette RFID (20), et sachant que le procédé comprend en outre l'étape d'exécution par l'au moins un dispositif étiquette RFID (20) de l'opération (140) conformément à la deuxième consigne.
     
    3. Procédé selon la revendication 1 ou 2,
    sachant que le message de réponse (110) comprend un accusé de réception signifiant la réception concluante du message de demande.
     
    4. Procédé selon l'une quelconque des revendications 1 à 3,
    sachant que l'utilisation de l'énergie par l'au moins un dispositif étiquette RFID (20) comprend le stockage de l'énergie dans un dispositif de stockage d'énergie (C) qui peut être connecté à l'au moins un dispositif étiquette RFID (20) et/ou la fourniture de l'énergie à un capteur (S) qui peut être connecté au dispositif étiquette RFID (20).
     
    5. Procédé selon l'une quelconque des revendications 1 à 4,
    sachant que l'envoi par le dispositif lecteur RFID (10) du signal de mise sous énergie (120) comprend le changement d'un mode de transmission du dispositif lecteur RFID en un mode d'onde constante, l'activation d'un signal porteur RFID dans le dispositif lecteur RFID (10) et l'émission dudit signal porteur représentant le signal de mise sous énergie (120) .
     
    6. Procédé selon l'une quelconque des revendications 1 à 5,
    sachant que la conversion du signal de mise sous énergie (120) en énergie comprend le redressement du signal de mise sous énergie (120) et la fourniture d'un signal de courant continu (VDC) à partir de ce redressement.
     
    7. Procédé selon l'une quelconque des revendications 1 à 6,
    sachant que, pendant l'envoi par le dispositif lecteur RFID (10) du signal de mise sous énergie (120), le procédé comprend en outre l'envoi par le dispositif lecteur RFID (10) d'un autre message et la réception dudit autre message par l'au moins un dispositif étiquette RFID (20).
     
    8. Procédé selon l'une quelconque des revendications 1 à 7,
    comprenant en outre, pendant la conversion du signal de mise sous énergie (120) en énergie, l'adaptation dynamique d'une quantité de ladite énergie à une situation de charge présente à l'intérieur du dispositif étiquette RFID (20) et/ou à une situation de charge présente à l'intérieur d'un capteur (S) qui peut être connecté au dispositif étiquette RFID (20).
     
    9. Système RFID comportant un dispositif lecteur RFID (10) et au moins un dispositif étiquette RFID (20), sachant que le système RFID est apte à exécuter le procédé selon l'une des revendications 1 à 8.
     
    10. Système RFID selon la revendication 9,
    sachant que le dispositif étiquette RFID (20) comprend
    une antenne (21),
    un circuit frontal analogique (22) qui est connecté à l'antenne (21) et est apte à recevoir le message de demande (100) et le signal de mise sous énergie (120) envoyés par le dispositif lecteur RFID (10) et à envoyer le message de réponse (110) au dispositif lecteur RFID (10) moyennant l'antenne,
    un composant de gestion de puissance (23) qui est connecté au circuit frontal analogique (22), et
    un circuit logique (24) qui est couplé au circuit frontal analogique (22) et au composant de gestion de puissance (23) pour la commande respective de ceux-ci,
    sachant que le composant de gestion de puissance (23) comporte un circuit redresseur (231) qui est conçu pour redresser le signal de mise sous énergie (120) et fournir l'énergie à partir de là.
     
    11. Système RFID selon la revendication 10,
    sachant que le composant de gestion de puissance (23) du dispositif étiquette RFID (20) comprend en outre un circuit de pompe de charge (232) qui est connecté au circuit redresseur (231) et est conçu pour recevoir l'énergie depuis le circuit redresseur (231), convertir ladite énergie en un niveau supérieur et fournir à partir de là l'énergie au niveau supérieur.
     
    12. Système RFID selon la revendication 10 ou 11,
    sachant que le composant de gestion de puissance (23) du dispositif étiquette RFID (20) comprend en outre un composant de sélection de mode de puissance (233) qui est apte à configurer le circuit frontal analogique (22) pour le mode de haute puissance ou le mode de fonctionnement RFID sous commande du circuit logique (24).
     
    13. Système RFID selon l'une quelconque des revendications 10 à 12,
    sachant que le composant de gestion de puissance (23) du dispositif étiquette RFID (20) comprend en outre un composant de contrôle (234) qui est conçu pour mesurer une quantité de puissance requise par le dispositif étiquette RFID (20) et/ou une quantité de puissance requise par un capteur (S) qui peut être connecté au dispositif étiquette RFID (20) et fournir à partir de là un signal d'état au circuit logique (24),
    et sachant que le circuit logique (24) est conçu pour configurer le composant de gestion de puissance (23) conformément au signal d'état.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description