JP5582940B2 - Proximity feeding / communication equipment - Google Patents

Description

  The present invention relates to a proximity power feeding / communication device, and in particular, proximity power feeding / communication capable of performing proximity power feeding from a base station side to a portable device side and improving a communication speed and a communicable area between the base station and the portable device. Relates to the device.

  A device that uses electromagnetic induction energy based on a radiated magnetic field of an electromagnetic wave transmitted from a base station as operating energy of a portable device, that is, a device that obtains operating energy of a portable device from the base station side by proximity power feeding is known.

  Conventionally, keyless entry devices for automobiles, RFID tag devices, IC card devices, and the like have been put to practical use as such devices. In these devices, the frequency used for proximity power feeding and communication is generally the same, and the base station and the portable device communicate using the same frequency as the electromagnetic wave used for proximity power feeding.

  For example, in the case of a keyless entry device for an automobile, the base station on the automobile side and the portable device on the key side each include an LF (Low Frequency) transmitter and an LF receiver, and communicate with proximity power feeding using an LF signal. . In this case, the timing at which proximity power feeding from the base station to the portable device is different from the timing at which the response signal is transmitted from the portable device to the base station. This is because transmission and reception cannot be performed simultaneously at the same frequency.

  In the method using LF signals of the same frequency, first, a LF signal for proximity power feeding is transmitted from the LF transmitter of the base station. The portable device receives the LF signal for proximity feeding transmitted from the base station, generates power based on the radiated magnetic field of the electromagnetic wave, operates the LF receiver and LF transmitter with the power, and outputs the LF response signal. Send. After the transmission of the proximity power feeding LF signal is completed, the base station receives the LF response signal transmitted from the LF transmitter of the portable device by the LF receiver.

  The same applies to the RFID tag device.The base station on the IC tag reader side and the portable device on the IC tag side each have an RF (Radio Frequency) transmitter and an RF receiver, and communicate with proximity power feeding using RF signals. I do. Even in this case, since transmission and reception cannot be performed simultaneously at the same frequency, the timing at which proximity power feeding from the base station to the portable device is different from the timing at which the response signal is transmitted from the portable device to the base station.

  In a method using RF signals of the same frequency, first, a proximity feed RF signal is transmitted from an RF transmitter of a base station. The portable device receives the proximity feed RF signal transmitted from the base station, generates power based on the radiated magnetic field of the electromagnetic wave, and operates the RF receiver and RF transmitter with the power to generate an RF response signal. Send. The base station receives the RF response signal transmitted from the RF transmitter of the portable device by the RF receiver after completing the transmission of the RF signal for proximity power feeding. The same applies to an IC card device that communicates with proximity power feeding using an RF signal.

  Non-Patent Document 1 describes an entrance / exit management system that activates a portable device using an LF signal and transmits a response signal from the portable device to a base station using a UHF signal. This entrance / exit management system includes a tag reader, an external antenna, and an active tag. Here, the tag reader includes an LF transmission / reception antenna, an LF transmission / reception circuit, a UHF antenna, a UHF reception circuit, a control circuit (CPU), an external antenna includes an LF antenna and an LF transmission circuit, an active tag includes an LF transmission / reception antenna, LF transceiver circuit, UHF antenna, UHF transmitter circuit, control circuit (CPU) and battery. If the battery is not depleted, the active tag is activated by the activation pattern of the LF signal from the tag reader, and transmits the UHF response signal including the ID number to the tag reader through the UHF transmission circuit. However, when the battery is depleted, the active tag operates with the electric power induced by the LF signal from the tag reader, and sends the binary FSK (Frequency Shift Keying) modulated LF signal to the tag reader. The tag reader receives this LF signal by the LF receiving circuit.

Naoshima Hideo et al., "Hands-free entry / exit management system using active tags" Panasonic Electric Works Technical Report (Vol.57 No.2), pp. 52-57

  In a device that transmits a LF signal from a base station to a portable device and supplies power in proximity, the portable device uses electromagnetic induction energy based on the radiated magnetic field of the electromagnetic wave of the LF signal as operating energy. The distance between the LF reception antennas of the portable device, that is, the service area, is limited to a radius of several meters from the LF transmission antenna of the base station in view of the characteristics of electromagnetic waves permitted by the Radio Law.

  On the other hand, if the LF transmission antenna connected to the LF transmission circuit on the base station side is simply extended with a cable to expand the service area, impedance matching between the LF transmission circuit, the LF antenna, and the cable becomes difficult. Occurs. In addition, the transmission efficiency between the LF transmission circuit and the LF transmission antenna is reduced, the external noise is likely to be superimposed on the LF transmission antenna, and the problem of circuit configuration such as the occurrence of EMC is increased. There also arises a problem that it is difficult to obtain a stable operation.

  Also, if you increase the reception sensitivity by installing a power amplifier circuit on the portable device side to expand the service area, the adverse effect of increasing the sensitivity on the reception side is from the LF transmission circuit on the base station side to the LF transmission antenna. Gain, frequency variation, and phase variation for various instability factors such as impedance matching variation, impedance matching mismatch, output of LF signal transmitted from base station and frequency variation, fading phenomenon due to external instability factors, etc. As a result, the circuit becomes extremely sensitive to factors that determine reception characteristics such as the signal-to-noise ratio, and as a result, the range of variation between components and elements that make up the base station LF transmitter circuit and portable device LF receiver circuit is severely limited. Otherwise, the problem that stable operation cannot be obtained becomes obvious. At the same time, it becomes susceptible to electromagnetic radiation from external electromagnetic waves, and as a result, there arises a problem that communication between the base station and the portable device is susceptible to noise in the sense that it is susceptible to these influences.

  It is an object of the present invention to avoid the problems of high frequency transmission and circuit design such as the problem of impedance matching mismatch and the generation of unnecessary radiation, and the installation surface and arrangement of the transmission antenna and the base station in the base station. An object of the present invention is to provide a proximity power feeding / communication device that can increase the degree of freedom and can freely set a service area.

In order to solve the above-mentioned problems, the present invention provides proximity power feeding from a base station side having a base station control circuit to a portable machine side having a portable device control circuit and performing communication between the base station and the portable device. In a communication apparatus, a transmission circuit front stage having a function of transmitting a signal transmitted from a base station control circuit as a digital signal to a transmission circuit on the base station side, and a function of transmitting the digital signal after performing high frequency modulation on the transmission signal The transmission circuit is separated into a rear stage, and the transmission circuit front stage and the transmission circuit rear stage are connected by a transmission buffer, a digital signal transmission path, and a reception buffer, and the reception buffer, the transmission circuit rear stage, a power amplifier, and a transmission an antenna configured as a power amplifier built transmitting antenna unit, LF signal to the portable device from the base station is transmitted, UHF signal to the base station from the portable device The base station control circuit and the portable device control circuit are configured to specify an LF signal transmission period, an LF signal reception period, a UHF signal transmission period, and a UHF signal reception period, and receive an LF signal with respect to the LF signal transmission period. The timing is controlled so that the period is delayed by the first time τ1 corresponding to the spatial propagation delay of the LF signal, and the UHF signal reception period is reduced to the spatial propagation delay of the UHF signal relative to the UHF signal transmission period. The timing is controlled so as to be delayed by the corresponding third time τ3, and the portable device control circuit is configured such that the start time of the UHF signal transmission period is the UHF signal on the portable device side with respect to the end time of the LF signal reception period. Is controlled so as to be delayed by a second time τ2 that can avoid being affected by the LF signal, and the start time of the UHF signal reception period at the base station is the first, from the end of the LF signal transmission period, Second and third time It is characterized in that it is delayed by a time (τ1 + τ2 + τ3).

  In the present invention, the power amplifier built-in transmission antenna unit further includes an output adjustment volume or an output adjustment attenuator.

  In the present invention, a plurality of power amplifier built-in transmission antenna units are arrayed to form a power amplifier built-in transmission antenna unit group, and the power amplifier built-in transmission antenna unit group is used to perform LF for one service area. It is characterized by transmitting a signal.

  In addition, the present invention is characterized in that a plurality of power amplifier built-in transmission antenna unit groups are used and signals are transmitted to a plurality of service areas.

Furthermore, the present invention, the transmission circuit front portion, a signal the base station controller sends out to Manchester encoding, is characterized by sending a digital signal.

  In the present invention, the transmission circuit on the base station side is separated into a transmission circuit front-stage part and a transmission circuit rear-stage part, and the reception buffer, transmission circuit rear-stage part, power amplifier and transmission antenna are configured as a power amplifier built-in transmission antenna unit. Since digital signals are transmitted to the transmitting antenna unit with a built-in amplifier, high-frequency transmission and circuits such as impedance matching mismatch problems due to the wiring length between the control circuit part in the base station and the LF transmitting antenna, and unnecessary radiation generation problems associated with analog transmission Can solve various design problems. As a result, it is possible to increase the degree of freedom in installation and arrangement of the transmission antenna and the base station, and it is possible to freely set the service area (the electromagnetic wave radiation space of the transmission signal).

  In addition, the service area can be expanded by arranging multiple amplifier built-in LF transmission antenna units to form an amplifier built-in LF transmit antenna unit group, and the service area can be freely formed by multiple LF transmit antennas. it can. Furthermore, the service area can be further expanded by using a plurality of amplifier built-in LF transmitting antenna units. As a result of being able to freely expand the service area and form the service area, it is possible to improve the stability in communication between the mobile device possessed by the moving user and the base station.

  In addition, by transmitting a LF band signal from the base station to the mobile device and transmitting a UHF band signal from the mobile device to the base station, the area that can receive proximity power supply from the base station to the mobile device is expanded. Thus, the area where the power supply service can be substantially realized can be expanded.

It is a block diagram which shows embodiment of the base station which comprises the proximity electric power feeding and communication apparatus which concerns on this invention. It is a block diagram which shows embodiment of the portable device which comprises the proximity electric power feeding and communication apparatus which concerns on this invention. 1 is a block diagram showing an embodiment of an entire proximity power feeding / communication device according to the present invention. FIG. It is a time chart which shows an example of the timing of transmission and reception between the base station of this invention, and a portable device. It is a flowchart which shows the basic operation | movement in this invention. It is a block diagram which shows other embodiment of the whole proximity | contact electric power feeding and communication apparatus which concerns on this invention. It is a block diagram which shows other embodiment of the whole proximity | contact power supply and communication apparatus which concerns on this invention.

  The present invention will be described below with reference to the drawings. In the following, the signal transmitted from the base station to the portable device is the LF band, and the signal transmitted from the portable device to the base station is the UHF band, but in the present invention, the signal transmitted from the base station to the portable device, The signal transmitted from the portable device to the base station is not limited to this example. However, the signal transmitted from the base station to the portable device is preferably in the LF band because of the power feeding efficiency of the proximity power feeding.

  FIG. 1 is a block diagram showing an embodiment of a base station constituting a proximity power feeding / communication device according to the present invention.

  The base station of the present embodiment includes an LF transmission antenna 1, an output adjustment volume 2, a power amplifier 3, an LF transmission circuit rear stage 4, a reception buffer 5, a digital signal transmission path 6, a transmission buffer 7, an LF transmission circuit front stage 8, A base station control circuit 9, a UHF receiving circuit 10, and a UHF receiving antenna 11 are provided. The output adjustment volume 2 may be an output adjustment attenuator.

  The LF transmission antenna 1 to the front part 8 of the LF transmission circuit are configured to transmit the LF signal from the LF antenna 1, and the proximity power feeding LF that performs power feeding to the portable device by the radiated magnetic field of the electromagnetic wave of the LF signal It functions as a transmission means. The LF signal can include, for example, a communication LF signal such as a portable device activation signal or an authentication signal. In this case, the portion of the LF transmission antenna 1 to LF transmission circuit front stage 8 is a portable device. It also functions as a communication LF transmission means for transmitting a communication LF signal. The front part 8 of the LF transmission circuit has a function of sending the signal sent from the base station control circuit 9 as a digital signal, and the rear part 4 of the LF transmission circuit modulates the digital signal at a high frequency to transmit the signal in the LF band. As a function of sending out. The output volume 2 adjusts the output transmitted from the LF transmission antenna 1, but may be omitted.

  The LF transmission antenna 1, output adjustment volume 2, power amplifier 3, LF transmission circuit rear stage 4 and reception buffer 5 are configured as an amplifier built-in LF transmission antenna unit 100. The amplifier built-in LF transmission antenna unit 100 receives a signal transmitted from the base station control circuit 9 via the LF transmission circuit front stage 8, the transmission buffer 7, and the digital signal transmission path 6. The signal received by the amplifier built-in LF transmission antenna unit 100 is converted into a digital signal by the LF transmission circuit front stage 8. This digital signal is, for example, a Manchester encoded signal, and is transmitted to the amplifier built-in LF transmission antenna unit 100 via the transmission buffer 7 and the digital signal transmission path 6. Manchester encoding can be realized with a relatively simple circuit configuration because “1” is represented by a transition from a high potential to a low potential and “0” is represented by a transition from a low potential to a high potential. It is.

  In the amplifier built-in LF transmission antenna unit 100, the reception buffer 5 shapes the waveform of the digital signal that has deteriorated due to the influence of parasitic capacitance or the like during the transmission of the digital signal transmission path 6 to compensate for the original 1,0 digital signals. It has a function. The digital signal whose waveform deterioration has been compensated is subjected to high frequency modulation in the latter stage 4 of the LF transmission circuit, and becomes a transmission signal in the LF band. The LF signal is further amplified by the power amplifier 3, further level-adjusted by the output adjustment volume 2, and then transmitted from the LF transmission antenna 1.

  The UHF receiving antenna 11 and the UHF receiving circuit 10 function as UHF receiving means for receiving a UHF response signal transmitted from a portable device. The UHF receiving circuit 10 also has a function of decrypting the UHF response signal if the UHF response signal transmitted from the portable device is encrypted. The UHF response signal received by the UHF receiving antenna 11 and the UHF receiving circuit 10 is sent to the base station control circuit 9.

  The base station control circuit 9 controls necessary control according to the UHF response signal received by the UHF reception antenna 11 and the UHF reception circuit 10, for example, in the case of an entrance / exit management device, controls the lock on and off of the room entrance door. For this purpose, the base station control circuit 9 includes an interface for exchanging data with an external device.

  Further, the base station control circuit 9 controls the timing at which the LF transmission circuit and the UHF reception circuit 10 including the LF transmission circuit front stage 8 and the LF transmission circuit rear stage 4 operate. Although this timing control will be described in detail later, the timing at which the base station transmits the LF signal and the timing at which the UHF response signal is received do not overlap. At this time, the spatial propagation delay of the LF signal is also taken into consideration.

  As described above, in the base station, the LF transmission circuit is divided into the LF transmission circuit front-stage unit 8 and the LF transmission circuit rear-stage unit 4 and connected between them via the transmission buffer 7, the digital signal transmission path 6, and the reception buffer 5. Since the signal transmitted from the base station control circuit 9 is transmitted as a digital signal, and the LF transmitting antenna unit 100 with a built-in amplifier performs high frequency modulation, an LF signal is transmitted, and further amplified and transmitted to the LF transmitting antenna 1. Various problems in high-frequency transmission and circuit design, such as the problem of impedance matching mismatch between the antenna and the transmission circuit and the problem of generation of unwanted radiation, can be solved. Therefore, each time the LF transmission antenna 1 is arranged or each time the LF transmission antenna 1 is changed, the LF signal is sent to the LF transmission antenna 1 without taking into consideration and countermeasures such as impedance matching mismatch problems and unnecessary radiation problems individually. The wiring length of the digital transmission path for transmission can be freely determined. As a result, the degree of freedom of the arrangement of the LF transmitting antenna 1 can be increased, so that the service area (the electromagnetic wave radiation space of the LF signal) can be set freely, and the installation and setting of the system becomes easy. In addition, by adjusting the output adjustment volume 2 provided in the amplifier built-in antenna unit 100, it becomes possible to improve the environment of a finer service area.

  FIG. 2 is a block diagram showing an embodiment of a portable device constituting the proximity power feeding / communication device according to the present invention.

  The portable device 18 of this embodiment includes an LF reception antenna 12, an LF reception circuit 13, a portable device control circuit 14, a UHF transmission circuit 15, and a UHF transmission antenna 16.

  The LF reception antenna 12 and the LF reception circuit 13 have a function of receiving the LF signal transmitted from the base station and demodulating the received LF signal. The LF receiving circuit 13 has a function of decrypting the LF signal transmitted from the base station if the LF signal is encrypted. Further, the LF receiving circuit 13 is further powered by electromagnetic induction by the radiated magnetic field received by the LF receiving antenna 12. It also has a function of generating Therefore, the LF reception circuit 13 includes a rectifier circuit that rectifies power from the LF reception antenna 12 and a capacitor that stores the power. The electric power thus generated is used as operating energy for each part of the portable device.

  The portable device control circuit 14 controls the timing at which the LF reception circuit 13 and the UHF transmission circuit 15 operate, and in accordance with the LF signal received via the LF reception antenna 12 and the LF reception circuit 13, Processing such as startup and display on the display is performed. Further, a UHF signal including a predetermined command and ID data is transmitted to the base station via the UHF transmission circuit 15 and the UHF transmission antenna 16.

  In the timing control in which the LF reception circuit 13 and the UHF transmission circuit 15 operate, the timing for transmitting the UHF response signal and the timing for receiving the LF signal are not overlapped as in the base station. At this time, the spatial propagation delay of the UHF response signal is also taken into consideration. Specifically, the timing control by the portable device control circuit 14 is performed corresponding to the timing control in the base station control circuit 9. This timing control can be realized by controlling using a counter, for example, based on the timing at which the signal transmitted from the base station is received by the portable device.

  FIG. 3 is a block diagram showing an embodiment of the entire proximity power feeding / communication device according to the present invention. In the present embodiment, a proximity power feeding / communication device is configured by combining the base station of FIG. 1 and the portable device of FIG.

  According to this embodiment, every time the LF transmission antenna 1 is arranged or every time the LF transmission antenna 1 is changed, the base station control is performed without taking into account and taking countermeasures for impedance matching mismatch and unnecessary radiation individually. The length of the digital signal transmission path 6 connecting the circuit 9 to the transmission buffer 7 and the amplifier built-in antenna unit 100 can be freely determined. Thereby, the degree of freedom in arrangement of the LF transmitting antenna 1 can be increased, and the service area 17 (the electromagnetic wave radiation space of the LF signal) can be freely set, so that the installation and setting of the system is facilitated.

  Further, in the above-described embodiment, proximity power feeding from the base station to the portable device and transmission of a response signal from the portable device to the base station are performed using frequency bands such as LF band and UHF band that are greatly different. According to this, it is possible to increase the power supply efficiency at the time of proximity power supply from the base station to the portable device, and it is possible to increase the speed of communication from the portable device to the base station. In addition, encryption can be easily applied, and the electromagnetic noise effect due to harmonics can be reduced.

  Furthermore, as described later, in the base station, by preventing the timing at which the LF signal is transmitted and the timing at which the UHF response signal is received, the electromagnetic wave of the LF signal transmitted from the LF transmission circuit through the LF transmission antenna. Suppresses noise caused by the electromagnetic field entering the UHF response signal and noise caused by the mutual electromagnetic field induced on the conductor pattern between the antenna loop of the LF transmitting antenna and the antenna loop of the UHF receiving antenna Can do. As a result, in the base station, it is possible to prevent the reception of the UHF response signal from the UHF reception antenna by the radiated magnetic field of the electromagnetic wave of the LF signal transmitted from the LF transmission antenna. It is possible to prevent signal reception from becoming unstable.

  Also, in the portable device, UHF transmission due to power supply noise generated inside the portable device due to the radiated magnetic field received by the LF receiving antenna by preventing the timing of transmitting the UHF response signal and the timing of receiving the LF signal from overlapping The influence on the circuit and the influence of the LF signal on the UHF transmission circuit can be suppressed. As a result, in the portable device, it is possible to prevent the reception of the LF signal by the LF reception antenna due to the UHF response signal transmitted from the UHF transmission antenna of the portable device, and from the LF transmission antenna of the base station. The transmission of the UHF response signal can be prevented from becoming unstable due to the transmitted LF signal.

  By controlling the transmission / reception timing as described above, it is possible to suppress the decrease in the effective communication distance between the base station and the portable device as much as possible to increase the communicable distance and to realize stable communication. Note that this timing control also takes into account the spatial propagation delay of the LF signal and UHF response signal.

  The reception interference at the UHF receiving antenna due to the radiated magnetic field of the electromagnetic wave of the LF signal transmitted from the LF transmitting antenna of the base station is more effective by forming the LF transmitting antenna and the UHF receiving antenna separately from each other. Can be prevented. Specifically, the LF transmitting antenna and the UHF receiving antenna may be formed separately without being formed on the same conductor pattern.

  FIG. 4 is a time chart showing an example of transmission and reception timings between the base station and the portable device of the present invention.

  The base station repeats LF transmission timing and pause. Also, the UHF response reception timing is set in a preset period within the pause period. At the LF transmission timing, the proximity power supply burst signal (LF signal) and the communication signal (LF signal) are transmitted to the portable device, and at the UHF response reception timing, a UHF response signal from the portable device is awaited. The pause is provided so as not to continuously occupy one frequency (according to the Radio Law).

  The LF transmission timing period (TSL) is defined by the time until the operating energy is secured by proximity power feeding in the portable device. Proximity feeding is performed not only by burst signals for proximity feeding but also by LF transmission data. On the other hand, it is possible to substitute all of the proximity power supply burst signals with LF transmission data.

  For example, the LF transmission timing period (TSL) is obtained by preliminarily obtaining the time from when the portable device is completely in the initial state until the generation of operating energy necessary for starting each part of the portable device. Can do.

  The portable device repeats the LF reception timing and pause. Also, the UHF response transmission timing is set in a preset period within the pause period. The LF reception timing, pause, and UHF response transmission timing correspond to the LF transmission timing, pause, and UHF response reception timing at the base station, respectively.

  However, the LF reception timing and pause period are delayed by the delay correction amount τ1 with respect to the LF transmission timing and pause period on the base station side, and the UHF response reception timing is delayed by the delay correction amount τ3 with respect to the UHF response transmission timing. τ1 and τ3 are set to a time corresponding to the spatial propagation delay of the LF signal and the UHF response signal. Further, the start time of the UHF response transmission timing is delayed by the delay correction amount τ2 from the end time of the LF reception timing. The delay correction amount τ2 is set to, for example, a value corresponding to one bit of the LF signal (data) in order to reliably avoid the UHF response signal from being affected by the reception of the LF signal on the portable device side. Furthermore, when the base station side operates the LF transmission and the UHF reception continuously, the base station prevents the UHF response signal from the portable device from entering the LF transmission circuit side and disturbing the next LF transmission. The UHF transmission timing on the portable device side is set so that the UHF reception timing can be ended with an interval (for example, several msec to several tens msec) before the start time of the LF transmission timing on the side. As a result, in the base station, there is an interval between the LF transmission timing and the UHF response reception timing, so that the interference due to the LF signal wrapping around to the UHF reception circuit side does not occur.

  The portable device receives the proximity power supply burst signal transmitted from the base station at the LF transmission timing at the LF reception timing, and generates electric power by electromagnetic induction. Further, a response signal for LF transmission data is generated as necessary.

  The LF reception timing period (TRL) for performing LF reception is defined by the time until the operating energy of the portable device is secured. Specifically, the LF reception timing period (TRL) is set to be the same as the LF transmission timing period (TSL).

  The portable device uses the power generated by the proximity power supply from the base station as operating energy, and transmits a UHF response signal within the UHF response transmission timing as necessary. The UHF response transmission timing period (TSU) is defined by the operable time of the portable device. That is, the period (TSU) of the UHF response transmission timing is set in advance within a time that does not exceed the time during which the portable device can operate due to the operation energy generated by the proximity power supply from the base station.

  The base station waits for the UHF response signal transmitted from the portable device at the UHF response reception timing. The UHF response reception timing period (TRU) is defined based on the UHF response transmission timing period (TSU) defined by the operable time of the portable device. Specifically, the maximum value of the UHF response reception timing period (TRU) is the same as the maximum value of the UHF response transmission timing period (TSU) when considering retransmission of the UHF response signal from the mobile device side. The

  FIG. 4 shows a time chart in the case where the LF signal is transmitted twice from the base station. Actually, the LF signal is transmitted from the base station to the portable device, the LF signal is received, and proximity power feeding is performed. The operation of transmitting a UHF response signal from the portable device to be received and receiving the UHF response signal at the base station may be completed once or repeated three or more times.

  As shown in the time chart of FIG. 4, when transmitting and receiving LF signals and UHF signals between the base station and the portable device, the base station provides LF transmission by providing delay correction amounts τ1, τ2, and τ3. Noise caused by the radiated magnetic field of the electromagnetic wave of the LF signal transmitted from the antenna wraps around the UHF receiver circuit, and the electromagnetic waves induced on the conductor pattern between the antenna loop of the LF transmitter antenna and the antenna loop of the UHF receiver antenna Noise due to the antenna effect due to the field can be suppressed. Also, in mobile devices, noise caused by the UHF response signal transmitted from the UHF transmission antenna wrapping around to the LF reception circuit, induced on the conductor pattern between the antenna loop of the LF reception antenna and the antenna loop of the UHF transmission antenna It is possible to suppress noise caused by the antenna effect due to the mutual electromagnetic field. As a result, the effective communication distance between the base station and the portable device can be maximized.

  In order to ensure security during communication, it is preferable that the base station and the portable device have the function. To ensure security, for example, one or both of a method for individually identifying a base station and a portable device and a method for encrypting a communication LF signal can be used.

  In the method for individually identifying a base station and a mobile device, individual IDs are assigned to the base station and the mobile device in advance, and communication within the group is enabled based on the ID. To identify a base station belonging to a group capable of communication and a plurality of portable devices, register a combination table of the base station ID and a plurality of portable device IDs in the base station memory and the portable device memory respectively. The base station and the mobile device are individually identified using those IDs.

  Specifically, an LF signal including the base station ID is transmitted from the base station at the time of proximity power feeding. If the base station ID included in the received LF signal is a base station ID in a communicable group including the mobile device, the mobile device starts normally and transmits a UHF response signal including the mobile device ID . If the base station ID is not applicable, the portable device does not respond and does not output unnecessary UHF radio waves. The base station receives the UHF response signal transmitted from the portable device, and recognizes that it is a correct UHF response signal if the included portable device ID is a portable device ID in a communicable group including its own base station.

  In the method of encrypting the communication LF signal, a general rolling code method using an M-sequence counter can be adopted. In the data arrangement of the LF signal to be transmitted and the arrangement / extraction of valid data, the base station and mobile device belonging to the group use unique correspondence and initial values, and the communication LF signal is different from the simple rolling code method. Encryption and decryption may be performed.

  FIG. 5 is a flowchart showing the basic operation in the present invention. Here, a method of individually identifying the base station and the portable device is employed to ensure security.

  First, it is determined whether or not a trigger is given in the base station (S11). The trigger is given at each timing when the LF transmission timing (TSL) starts if the power of the base station is on. If no trigger is given, wait until a trigger is given. If a trigger is given, LF transmission timing (TSL) is reached, and the base station transmits an LF signal including its own base station ID (S12). The transmission of the LF signal is continuously performed during the LF transmission timing period (TSL), and ends when the LF transmission timing period (TSL) elapses.

  The portable device generates power by electromagnetic induction due to the electromagnetic field radiated from the LF signal transmitted from the base station (S13). The portable device uses the generated power as operating energy and activates each unit (LF reception circuit, portable device side control circuit, UHF transmission circuit) (S14 to S16). If a special signal such as an activation code signal is required for this activation, that signal is also included in the LF signal.

  Next, the portable device performs validity authentication based on the IF signal transmitted from the base station (S17). If the validity is authenticated here, the portable device transmits a UHF response signal (S18). Specifically, as described above, the validity authentication is performed based on the base station IDs constituting the group, and the base station ID included in the received LF signal includes the base stations in the communicable group including the own mobile device. If it is a station ID, it starts normally and transmits a UHF response signal including the ID of the portable device. However, if the validity is not authenticated, the process returns to step S11.

  The portable device transmits a UHF response signal within the UHF response transmission timing period (TSU) (S18). This UHF response signal includes the portable device ID. The base station receives the UHF response signal within the period (TRU) of the UHF response reception timing (S19). Here, the authenticity of the portable device is also performed using the base station ID included in the UHF response signal. Thereafter, the steps from S11 are repeated as necessary.

  FIG. 6 is a block diagram showing another embodiment of the entire proximity power feeding / communication device according to the present invention.

  In this embodiment, in order to expand the service area, two antenna units with a built-in amplifier are used, and these antenna units with a built-in amplifier are arranged in separate areas.

  Here, here, the antenna units 100-1 and 100-2 with built-in amplifier are used, and the transmission buffers 7-1 and 7-2 and the digital signal transmission line 6- are connected from the base station control circuit 9 and the front stage 8 of the LF transmission circuit. Digital signals are transmitted to the amplifier built-in antenna units 100-1 and 100-2 via 1 and 6-2. Note that the transmission of digital signals to the amplifier built-in antenna units 100-1 and 100-2 can be performed using a common (one) transmission buffer and digital transmission path. The amplifier built-in antenna units 100-1 and 100-2 transmit LF signals to the service areas 21-1 and 21-2, respectively. If more antenna units with built-in amplifiers are used, the service area as a whole can be further expanded.

  According to this embodiment, the antenna units with built-in amplifiers are arranged in areas that are separated from each other, and the LF signal can be transmitted from each antenna unit with built-in amplifier to each area. The area can be enlarged. At that time, the LF signal can be transmitted to each amplifier built-in antenna unit satisfactorily, and the length of the digital signal transmission path does not take into account the problem of impedance matching mismatch or the problem of unwanted radiation, and does not take countermeasures. Therefore, installation work and rearrangement of the LF transmitting antenna can be performed freely. Thus, by using a plurality of antenna units with built-in amplifiers, the service area can be expanded, and communication with the portable device 18 moving over a wide area becomes possible.

  FIG. 7 is a block diagram showing still another embodiment of the entire proximity power feeding / communication device according to the present invention.

  In this embodiment, an amplifier built-in antenna unit group is configured by arraying a plurality of amplifier built-in antenna units, and the amplifier built-in antenna unit group is configured to transmit an LF signal to one service area. It is.

  Here, the amplifier built-in antenna units 100-1 to 100-3 and 100-4 to 100-6 are respectively arrayed to form two amplifier built-in antenna units 200-1 and 200-2, and the base station control A digital signal is transmitted from the circuit 9 to each of the amplifier built-in antenna unit groups 200-1 and 200-2 via the transmission buffers 7-1 and 7-2 and the digital signal transmission paths 6-1 and 6-2. Yes. Note that digital signal transmission to the amplifier built-in antenna unit groups 200-1 and 200-2 is also possible using a common (one) transmission buffer and digital transmission path. Amplifier built-in antenna unit groups 200-1 and 200-2 transmit LF signals to service areas 21-1 and 21-2, respectively. If more amplifier built-in antenna unit groups are used, the service area as a whole can be further expanded.

  According to the present embodiment, it is possible to expand the service area in terms of compensating for the limitation due to the directivity of the LF transmission antenna, and the stability of communication with the mobile device on the move is improved. In addition, by adjusting the output adjustment volume provided in the antenna unit with a built-in amplifier, it becomes possible to improve the environment of the service area.

  Although the embodiment has been described above, the present invention is not limited to the above embodiment, and includes various modifications.

  For example, the base station in FIG. 1 includes a pair of LF transmission antennas 1 and LF transmission circuits 2 that are used for both proximity power feeding and communication. A circuit, a communication LF transmission antenna, and a communication LF transmission circuit may be provided, and the proximity power feeding transmission unit and the communication transmission unit may be configured separately. According to this configuration, since a low-impedance antenna can be used as the LF transmitting antenna for proximity feeding, the efficiency of proximity feeding between the base station and the portable device can be increased, and the frequency of the communication LF signal can be increased. The frequency of the LF signal for proximity power feeding can be varied.

  In addition, the portable device of FIG. 2 includes only one LF reception antenna and is configured to be used for both proximity power supply and communication, but is provided with a separate power supply LF reception antenna and a communication LF reception antenna. It can also be configured. In general, it is known that a low impedance antenna has good power efficiency for electromagnetic induction by a radiated magnetic field, and a high impedance antenna has good reception efficiency for receiving communication signals. Therefore, it is also preferable to separately provide a low impedance proximity feeding LF receiving antenna and a high impedance communication LF receiving antenna. In this case, in order to improve the directivity of the communication LF receiving antenna, the X-axis and Y-axis two-dimensional configuration antenna or the X-axis, Y-axis, and Z-axis three-dimensional configuration These antennas are preferred.

1,1-1 to 1-6 ... LF transmitting antenna, 2 ... Output volume, 3 ... Power amplifier, 4 ... Last stage of LF transmitting circuit, 5 ... Receiving buffer, 6,6 -1,6-2 ... Digital signal transmission path, 7,7-1,7-2 ... Transmission buffer, 8 ... Front part of LF transmission circuit, 9 ... Base station control circuit, 10. ..UHF receiver circuit, 11 ... UHF receiver antenna, 12 ... LF receiver antenna, 13 ... LF receiver circuit, 14 ... portable device control circuit, 15 ... UHF transmitter circuit, 16.・ UHF transmit antenna, 17,17-1,17-2 ・ ・ ・ Service area, 18 ・ ・ ・ Portable machine, 100,100-1 to 100-6 ・ ・ ・ LF amplifier with built-in amplifier, 200-1,200-2 ・..Group of LF transmitting antenna units with built-in amplifier

Claims (5)

In the proximity power supply and communication device that performs proximity power supply from the base station side including the base station control circuit to the mobile device side including the mobile device control circuit, and performing communication between the base station and the mobile device,
Transmission circuit subsequent to the base station control circuit of the transmission circuit of the base station side has a function of sending by high frequency modulation to the transmission signal transmission circuit front and the digital signal having the function of sending to a digital signal a signal to be sent is Divided into parts,
A transmission buffer, a digital signal transmission path and a reception buffer are connected between the transmission circuit front stage and the transmission circuit rear stage,
The reception buffer, the transmission circuit rear stage, a power amplifier and a transmission antenna are configured as a power antenna built-in transmission antenna unit ,
An LF signal is transmitted from the base station to the portable device, a UHF signal is transmitted from the portable device to the base station,
The base station control circuit and the portable device control circuit define an LF signal transmission period, an LF signal reception period, a UHF signal transmission period, and a UHF signal reception period, and an LF signal reception period with respect to the LF signal transmission period, The timing is controlled so as to be delayed by a first time τ1 corresponding to the spatial propagation delay of the LF signal, and the UHF signal reception period is equal to the spatial propagation delay of the UHF signal relative to the UHF signal transmission period. 3, and the portable device control circuit is configured such that the start time of the UHF signal transmission period relative to the end time of the LF signal reception period is the same as the LF signal on the portable device side. The timing is controlled so as to be delayed by a second time τ2 that can be avoided by the HF signal transmission, and the start time of the UHF signal reception period at the base station is The first than the end of the period, the sum of the second and third time period (τ1 + τ2 + τ3) only near the power feeding and communication apparatus characterized by being delayed.   The proximity power feeding / communication device according to claim 1, wherein the transmission antenna unit with a built-in power amplifier further includes an output adjustment volume or an output adjustment attenuator.   A plurality of power amplifier built-in transmission antenna units are arrayed to form a power amplifier built-in transmission antenna unit group, and an LF signal is transmitted to one service area using the power amplifier built-in transmission antenna unit group. The proximity power feeding / communication device according to claim 1 or 2,   The proximity power feeding / communication device according to claim 3, wherein a plurality of power amplifier built-in transmitting antenna unit groups are used to transmit signals to a plurality of service areas. The transmitting circuit front portion, a signal the base station controller is sending Manchester encoded, proximity feeding and communication apparatus according to any one of claims 1, characterized in that sending the digital signal 4.

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