JP2010200415A - Communication terminal and data communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication terminal which can prolong the service life of a battery installed as a power source, and to provide a data communication system. <P>SOLUTION: At normal times when smart communication is not communicated, the communication terminal switches off the first switch 25 and cuts off a communication control circuit 12 from a battery 19 and places the communication control circuit 12 to go into a power-off state. When an electronic key 2 receives power waves Svc transmitted from the transmitter 8 (9) of a vehicle 1, these power waves Svc are charged via a charge circuit 21. Then, when the charge value of the charge circuit 21 exceeds threshold, a first switch 25 is switched on, and the communication circuit 12 becomes electrically connected to the battery 19, and switches into a power-on state. Consequently, the electronic key 2 is started, and smart communication with the vehicle 1 becomes executable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a communication terminal and a data communication system capable of transmitting various data to the outside by wireless communication.

  2. Description of the Related Art In recent years, as a vehicle key system, an electronic key system (see, for example, Patent Document 1) that uses an electronic key that wirelessly transmits a key code inherent to a key as a vehicle key has been widely used. When the vehicle receives the key code transmitted from the electronic key, the vehicle performs ID verification. If the key code of the electronic key matches the vehicle and ID verification is established, Allow or execute engine start. This type of electronic key system includes a wireless key system that requires button operation on the key side for key code transmission, and a key operation-free system that automatically returns a key code to the vehicle in response to a request issued from the vehicle. Etc.

JP 2008-231734 A

  Generally, an electronic key operates using a battery stored in the key as a power source. By the way, since the battery is in a state of being always connected to various electronic components of the key, for example, via wiring on the printed circuit board, a current flows through the electrical circuit of the key even while communication is not performed. A so-called standby current flows. As described above, when the standby current flows in the electric circuit of the key, the battery power is consumed as much as that, and this is a factor that deteriorates the battery life.

  In particular, since this type of electronic key communication is executed only a few times a day, such as the operation of locking and unlocking the door of the vehicle and the operation of starting the engine, the electronic key is in a standby state in most time zones. There is the present condition to take. For this reason, the battery life of the electronic key is greatly influenced by the standby current. Therefore, reducing the standby current as much as possible is very effective in extending the life of the electronic key. Is very meaningful. Further, since the key operation free system searches for a request and transmits a key code, a large amount of power is required, and in this case, there is a current situation in which battery power consumption is significant.

  An object of the present invention is to provide a communication terminal and a data communication system capable of extending the life of a battery included in the communication terminal as a power source.

  In order to solve the above problems, in the present invention, the control circuit that manages the execution operation of the data communication is operated by the power of the battery that it has, so that the data communication operation of at least one of data transmission and data reception is performed. In a communication terminal to be executed, a switch means provided between the control circuit and the battery, normally electrically disconnecting the battery from the control circuit and powering off the control circuit, and radio waves that can become electric power When the power radio wave transmitted from the outside is received by the antenna, the power radio wave is charged, and when the charge value exceeds a set value, the switch means is switched to a state where the battery and the control circuit are electrically connected. And charging means that enables data communication operation of the control circuit by turning on the control circuit. That.

  According to this configuration, when the communication terminal receives a power radio wave transmitted from the outside, the radio wave is charged by the charging unit. When the charged value exceeds the set value, the control circuit that has been electrically disconnected until then is connected to the battery, and the control circuit is turned on by using the battery as a power source. The operation can be executed. Therefore, in the case of this configuration, while the data communication operation is not performed, the battery is disconnected from the control circuit, and the electric circuit of the communication terminal is made an open circuit, so that no standby current flows through the electric circuit of the communication terminal. For this reason, the problem of power consumption caused by the standby current does not occur, and the battery life can be extended. In addition, when the data communication is not performed in this manner, even if the control circuit is in a standby state with the power off, the control circuit is activated by an electric power radio wave obtained from the outside. However, it is possible to start the control circuit without any problem when power is required to execute data communication.

  In the present invention, the monitoring means for monitoring whether or not the data transmission operation by the control circuit that is turned on is completed, and when the data transmission operation is completed, the power charged in the charging means is discharged to the outside. Thus, the present invention is characterized by comprising discharge means for returning the switch means to the original switch state and returning the control circuit to the original power-off state.

  According to this configuration, when the data transmission operation of the communication terminal is completed, the discharging means discharges the charging voltage required to switch the switching means to the operating state (that is, the state where the battery is connected to the control circuit), An operation is performed to return the switch means to the original non-operating state (ie, the state in which the battery is disconnected from the control circuit). For this reason, after the data transmission operation is completed, the switch means can be immediately returned to the original state before the operation.

  In the present invention, the data transmission / reception means enabling both data reception and data transmission, and the data content of the communication data received by the data transmission / reception means after the control circuit is connected to the battery by the charging are confirmed. The present invention is characterized by comprising a return means for forcibly discharging the charging means by the discharging means and immediately returning the switch means to the original state when the communication data is not normal.

  According to this configuration, for example, even if noise is received as a power radio wave and the control circuit is connected to the battery due to the noise and can operate, the control circuit cannot immediately receive normal data. Disconnected. For this reason, even if the control circuit takes a power-on state due to noise, the control circuit is not left in this power-on state, which is very effective in extending the battery life.

  In the present invention, a control circuit that manages data communication is operated by the power of a battery that is a power source of the terminal, whereby a communication terminal that executes at least one data communication operation of data transmission and data reception, and the communication terminal A data communication system including a communication device as a communication partner, which is provided between the control circuit and the battery, and normally electrically disconnects the battery from the control circuit and turns off the control circuit. When the antenna receives a power radio wave transmitted from the communication device as a radio wave that can be converted into electric power, the battery and the control circuit are charged when the power radio wave is charged and the charge value exceeds a set value. By switching the switch means to an electrically connected state and powering on the control circuit, the data communication operation of the control circuit is performed. And gist that a charging means for the ability.

  ADVANTAGE OF THE INVENTION According to this invention, the lifetime of the battery with which a communication terminal is provided as a power supply can be achieved.

The block diagram which shows schematic structure of the electronic key system in one Embodiment. The block diagram which shows schematic structure of the electronic key system to which a wireless power transmission system is applied. The block diagram which shows the state in which the communication control circuit was connected to the battery by the electric power radio wave. The block diagram which shows the state from which the charging circuit was discharged and the communication control circuit was cut away from the battery. The wave form diagram which shows the specific waveform of an electric power electric wave and a request electric wave. The graph which shows the relationship between the charge time of a charging circuit, and a charge value. The block diagram which shows the other structural example of the vehicle side of the electronic key system in another example.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of a communication terminal and a data communication system embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the vehicle 1 includes an electronic key system 3 that performs key verification using a key code with an electronic key 2 that is used as a vehicle key, and a vehicle door (including a seat door and a luggage door). A door lock system 4 that locks and unlocks the door lock, and an engine system 5 that manages the power state (power position) and engine start / stop of the vehicle 1 are provided. The electronic key 2 is capable of narrow-area wireless communication with the vehicle 1, and transmits the ID code inherent to the electronic key 2 to the vehicle 1 by wireless communication to cause the vehicle 1 to perform key verification. A key that can be used. The vehicle 1 corresponds to a communication device, and the electronic key 2 corresponds to a communication terminal.

  The electronic key system 3 includes a key operation free system 6 that does not require individual key operations when the electronic key 2 transmits an ID code. The key operation free system 6 includes a smart entry system as a function that does not require a key operation at the time of door lock locking / unlocking operation. In this smart entry system, the vehicle 1 is provided with a verification ECU (Electronic Control Unit) 7 that performs key verification (ID verification) with the electronic key 2. The verification ECU 7 includes, for example, an in-vehicle transmitter 8 installed in a vehicle door or the like to transmit an RF band (Radio Frequency: about 312 MHz) signal to the outside of the vehicle, an in-car floor to transmit the same RF band signal to the inside of the vehicle, and the like. An in-vehicle transmitter 9 installed in the vehicle and a vehicle tuner 10 capable of receiving an RF band signal are connected. The verification ECU 7 is connected to the door lock system 4 and the engine system 5 via an in-vehicle LAN (Local Area Network) 11 that is one network in the vehicle.

  Further, the electronic key 2 is provided with a communication control circuit (control IC: Integrated Circuit) 12 that performs overall control of various operations of the electronic key 2. The communication control circuit 12 includes various devices such as a CPU (Central Processing Unit) 13 and a memory 14, and an ID code is registered in the memory 14 as a unique key code of the electronic key 2. The communication control circuit 12 is connected to a key receiver 15 capable of receiving an RF band radio signal and a key transmitter 16 capable of transmitting an RF band radio signal. The communication control circuit 12 sequentially monitors which type of radio signal is received by the key receiver 15 and manages the operation of signal transmission from the key transmitter 16. The communication control circuit 12 constitutes a control circuit and data transmission / reception means, and the key receiver 15 and the key transmitter 16 also constitute a data receiver.

  When the vehicle 1 is in a parked state, the verification ECU 7 intermittently transmits an RF band request signal Srq from the vehicle transmitter 8 to form a vehicle communication area for the request signal Srq around the vehicle, thereby narrow-band wireless communication ( Hereinafter, the establishment of smart communication) is attempted. When the electronic key 2 enters the outside communication area and receives the request signal Srq, the electronic key 2 responds to the request signal Srq and sends the ID signal Sid carrying the ID code registered in its own memory 14 to the RF band. Reply with the signal. When smart communication (external communication) is established by receiving the ID signal Sid with the tuner 10, the verification ECU 7 compares the ID code registered in its own memory 17 with the ID code of the electronic key 2, so-called ID verification. Perform smart verification (external verification). The verification ECU 7 permits or executes the door lock locking / unlocking operation by the door lock system 4 when confirming that this external verification is established. The request signal Srq corresponds to communication data.

  In addition, the key operation free system 6 can start and stop the engine (not shown) only by a switch operation on the vehicle 1 without requiring an actual vehicle key operation at the time of engine start / stop operation. One feature is the one-push engine start system. In this one-push engine start system, for example, when the driver enters the vehicle by a courtesy switch (not shown), the verification ECU 7 does not start from the previous external transmitter 8 but this time from the internal transmitter 9. A request signal Srq is transmitted to form an in-vehicle communication area throughout the vehicle. When the tuner 10 receives the ID signal Sid returned by the electronic key 2 entering the in-vehicle communication area and the smart communication (in-vehicle communication) is established, the verification ECU 7 establishes the ID code and the electronic key 2 registered in itself. ID verification, so-called smart verification (in-vehicle verification), is performed by checking the ID code. When the verification ECU 7 confirms that the in-vehicle verification has been established, the verification ECU 7 permits the engine system 5 to switch the power supply state.

  As a result, when the push momentary engine switch (not shown) is pushed while the brake pedal is depressed while the engine is in the stopped state, the engine that has been in the stopped state is switched to the activated state. When the engine is in a movable state, if the engine switch is pushed while the range position of the select lever is in the parking position (P range), the engine is now switched to a stopped state. In addition, when the engine is stopped, if only the engine switch is pushed without depressing the brake pedal, the power state will be switched off every time this push operation is performed → ACC on (accessory on) → IG on (ignition) (On) repeatedly.

  As shown in FIG. 2, in the electronic key system 3, a power radio wave Svc that can be a power source of the electronic key 2 is transmitted from the vehicle 1, and the electronic key 2 is operated by the power radio wave Svc to make the electronic key 2 smart. A wireless power transmission system 18 for executing communication is provided. The wireless power transmission system 18 of this example simultaneously transmits a power radio wave Svc as a radio wave that can serve as a driving power source for the electronic key 2 when the request signal Sr q is transmitted from the vehicle 1. The battery connection of the electronic key 2 is turned on, that is, the battery 19 that the electronic key 2 has as its driving source is switched to a state in which the electronic key 2 is electrically connected to the communication control circuit 12 so that smart communication by the electronic key 2 can be performed. System.

  In this case, the vehicle-side transmitter 8 (in-vehicle transmitter 9) of the vehicle 1 is provided with a power transmission processing unit 20 that transmits a request signal Srq by adding a power radio wave Svc to the request signal Srq. Prior to the transmitters 8 and 9 transmitting the request signal Srq to the electronic key 2, the power transmission processing unit 20 transmits the electric power radio wave Svc toward the vehicle 1 using the RF band frequency. Since the electric power radio wave Svc only needs to be used as a radio wave for the power source of the electronic key 2, it does not include special data contents but is a radio wave having a waveform along the period of the RF band. When transmitting the request signal Srq to the electronic key 2, the outside transmitter 8 (in-vehicle transmitter 9) first transmits a power radio wave Svc by the power transmission processing unit 20, and then transmits the request signal Srq following this transmission. Execute smart communication by taking the action. For example, RFID (Radio Frequency Identification) is adopted as a communication standard for smart communication.

  The electronic key 2 is provided with a charging circuit 21 that charges the wireless power of the power radio wave Svc transmitted from the vehicle 1. The charging circuit 21 is provided with a receiving antenna 22 for a power radio wave Svc and a series circuit of a diode 23 and a capacitor 24 as a power charging location. When the receiving circuit 22 receives the power radio wave Svc, the charging circuit 21 stores the power component that can be generated from the power radio wave Svc as a charge in the capacitor 24, thereby charging the wireless power of the power radio wave Svc. The diode 23 functions as an element that prevents a reverse current flow in the charging circuit 21. The charging circuit 21 corresponds to charging means, and the receiving antenna 22 corresponds to an antenna.

  In addition, a first switch 25 is provided between the communication control circuit 12 and the battery 19 to switch on and off the electrical connection between the two. The first switch 25 sets whether the communication control circuit 12 is electrically connected to the battery 19 or is electrically disconnected from the battery 19. The first switch 25 of this example uses, for example, a bipolar transistor, an emitter terminal connected to the communication control circuit 12, a base terminal connected to the intermediate terminal (node) of the diode 23 and the capacitor 24, and a collector terminal The battery 19 is connected to GND (ground). When the communication control circuit 12 is electrically disconnected from the battery 19 by the first switch 25, the electric circuit in the electronic key 2, that is, the peripheral circuit including the communication control circuit 12, becomes an open circuit, and the power is turned off. The first switch 25 corresponds to switch means.

  In this example, on / off of the first switch 25 is managed by the charge value (charge amount) of the charging circuit 21. That is, when the charging value of the charging circuit 21 exceeds the threshold value Vk (see FIG. 6), a high voltage is supplied from the charging circuit 21 to the base terminal of the first switch 25, and the first switch 25 is turned on from the off state so far. The operation switches to the state. As a result, as shown in FIG. 3, a drive current flows from the battery 19 to the communication control circuit 12, and the operation state of the communication control circuit 12 is switched from power-off to power-on. When the communication control circuit 12 is electrically connected to the battery 19 by turning on the first switch 25 and is turned on, various operations of data communication (for example, data reception and data transmission) by the communication control circuit 12 can be executed. . As described above, the electronic key 2 (communication control circuit 12) of this example takes the power-off state in which the operation is paused and waits for the execution of the communication not executing the smart communication, and turns on the power at the timing of executing the smart communication. Takes an action transition that switches to a state. Note that the threshold value Vk corresponds to a set value.

  The electronic key 2 is provided with a discharge circuit 26 that discharges the electric power charged in the charging circuit 21. The discharge circuit 26 switches the first switch 25 that has entered the ON state to the original OFF state by discharging the charge stored in the charging circuit 21. The discharge circuit 26 of this example includes a series circuit of a second switch 27 and a resistor 28. As the second switch 27, for example, a bipolar transistor is used, an emitter terminal is connected to GND via a resistor 28, a base terminal is connected to the communication control circuit 12, a collector terminal is the charging circuit 21 and the first switch 25. Is connected to an intermediate terminal (node). The discharge circuit 26 corresponds to a discharge unit.

  The communication control circuit 12 is provided with a discharge circuit control unit 29 that manages the operation of the discharge circuit 26. The discharge circuit control unit 29 monitors whether the smart communication executed by the communication control circuit 12 with the battery 19 as a power source is completed, and turns on the second switch 27 when confirming that the smart communication is completed. As a result, as shown in FIG. 4, the power charged in the charging circuit 21 flows to the GND side as a discharging current, and the charging circuit 21 is discharged. After a while, the first switch 25 is turned off. Accordingly, the communication control circuit 12 is in a power-off state in which the communication control circuit 12 is electrically disconnected from the battery 19, and the electronic key 2 is in a communication disabled state. The discharge circuit control unit 29 corresponds to the monitoring unit.

  Further, the communication control circuit 12 is provided with a data confirmation unit 30 for confirming whether data received by the key receiver 15 after power-on activation is regular data. The data confirmation unit 30 is activated when the first switch 25 is turned on and the communication control circuit 12 is turned on, and confirms whether or not the received data received by the key receiver 15 is normal thereafter. To do. When the data confirmation unit 30 confirms that the received data is normal, it continues the communication operation. When the data confirmation unit 30 confirms that the received data is not normal, the data confirmation unit 30 immediately activates the discharge circuit 26 to power the charging circuit 21. Is discharged, the first switch 25 is forcibly turned off to turn off the communication control circuit 12, and the communication operation is forcibly terminated. The data confirmation unit 30 corresponds to a return unit.

Next, the smart communication operation executed by the electronic key system 3 using the wireless power transmission system 18 of this example will be described with reference to FIGS.
As an operation performed by the key operation free system 6, the verification ECU 7 checks whether or not the electronic key 2 is present in the communication area of smart communication (external vehicle verification, in-vehicle verification). 9), the request signal Srq is intermittently transmitted to form a communication area for the request signal Srq. For example, when performing outside vehicle verification, the request signal Srq is intermittently transmitted from the outside transmitter 8 to the outside of the vehicle, and a communication area for the request signal Srq is formed around the vehicle. When performing in-vehicle collation, the request signal Srq is transmitted from the in-vehicle transmitter 9 to the entire area of the vehicle, and a communication area for the request signal Srq is formed in the entire area of the vehicle. In the following description, an example of vehicle outside verification will be given.

  As shown in FIG. 5, the verification ECU 7 first operates the power transmission processing unit 20 to transmit the electric wave Svc from the external transmitter 8 to the RF band as shown in FIG. 5 prior to transmitting the request signal Srq. Send with the signal. Then, after the transmission of the electric power radio wave Svc, the verification ECU 7 transmits the request signal Srq using a signal in the same RF band as that of the electric power radio wave Svc. That is, the verification ECU 7 continuously transmits these radio signals as RF band signals in the order of electric power radio wave Svc → request signal Srq, intermittently executes this transmission operation, and transmits the request signal Srq around the vehicle. Form an area.

  When the user holding the electronic key 2 approaches the vehicle 1 and the electronic key 2 enters the communication area outside the vehicle, the electronic key 2 firstly uses the electric wave Svc among the two radio waves transmitted from the vehicle 1 as a charging circuit. In this state, the signal is received by 21 receiving antennas 22. At this time, the charging circuit 21 enters a charging state by the received power radio wave Svc, and the charging circuit 21 is gradually charged as the power radio wave Svc is continuously received. When the charging value of the charging circuit 21 exceeds the threshold value Vk, the base voltage of the first switch 25 takes a high voltage, and the first switch 25 is turned on (state shown in FIG. 3). As a result, the communication control circuit 12 is electrically connected to the battery 19 and takes a power-on state where a power source necessary for operation is obtained. As a result, the communication control circuit 12 becomes operable and the smart communication operation can be executed.

  Since the request signal Srq is transmitted from the vehicle 1 following the power radio wave Svc, the communication control circuit 12 that has been activated by the power radio wave Svc continues to receive the key this time after receiving the power radio wave Svc. The machine 15 receives the request signal Srq. When the communication control circuit 12 receives the received data in the power-on state, the communication control circuit 12 processes the received data. When the communication control circuit 12 confirms that the received data is the request signal Srq, the communication control circuit 12 performs the smart communication operation in response to the request signal Srq. Execute. In this case, the communication control circuit 12 returns the ID signal Sid to the vehicle 1 and causes the vehicle 1 to execute ID verification. And if ID collation with the vehicle 1 is materialized, door lock locking / unlocking and engine starting will be permitted or performed.

  When the electronic key 2 enters the execution of smart communication, the discharge circuit control unit 29 monitors when the smart communication is finished. Then, when the discharge circuit control unit 29 confirms that all the data transfer of the smart communication has been completed, the discharge circuit control unit 29 recognizes that the smart communication that was being executed has ended, and turns on the second switch 27 of the discharge circuit 26 (FIG. 4). State). Thereby, the electric power stored in the charging circuit 21 flows through the discharging circuit 26 to the GND, and the charging circuit 21 is discharged. When the power of the charging circuit 21 becomes equal to or lower than the threshold value, the first switch 25 that has been on until then is turned off, and the communication control circuit 12 is electrically disconnected from the battery 19. As a result, the communication control circuit 12 returns to the power-off state and returns to a state where no standby current is generated. Further, when the communication control circuit 12 is turned off, the communication control circuit 12 enters a pause, so that the discharge operation is also terminated along with the pause operation.

  When the communication control circuit 12 is in a power-on state electrically connected to the battery 19, the data confirmation unit 30 confirms whether or not the reception data received by the electronic key 2 at this time is regular data. . The data confirmation unit 30 confirms whether or not the received data is regular data, for example, by referring to a start bit existing at the head of the received data. If the data confirmation unit 30 can confirm that the received data is regular data, the data confirmation unit 30 continues the communication operation. On the other hand, if it is confirmed that the received data is not regular data, it is determined that the communication control circuit 12 has been activated by another radio wave such as noise. Therefore, the data confirmation unit 30 immediately turns on the second switch 27 of the discharge circuit 26 to discharge the power of the charging circuit 21 and forcibly returns the communication control circuit 12 to the original power-off state.

  Therefore, in this example, during normal times when smart communication is not performed, the communication control circuit 12 is electrically disconnected from the battery 19 by the OFF state of the first switch 25 and is made to stand by with the power off. As a result, the electric circuit in the electronic key 2 becomes an open circuit and no standby current flows through the electronic key 2, so that it is possible to extend the life of the battery 19 correspondingly. When the electronic key 2 receives the power radio wave Svc transmitted from the vehicle 1, the first switch 25 is turned on by the power of the power radio wave Svc, and the communication control circuit 12 is electrically connected to the battery 19. In this state, data communication can be executed. Therefore, even if the electronic key 2 is turned off at the normal time when smart communication is not executed, the electronic key 2 is activated by the wireless power received from the outside. Therefore, even when the electronic key 2 is suspended at the normal time, It becomes possible to start without problems.

According to the configuration of the present embodiment, the following effects can be obtained.
(1) When normal communication is not performed, the communication control circuit 12 is disconnected from the battery 19 and the electronic key 2 is turned off. When the electronic key 2 enters the communication area for smart communication and receives the electric wave Svc, The communication control circuit 12 is connected to the battery 19 by the electric power radio wave Svc to turn on the electronic key 2 to execute smart communication. For this reason, when the power supply that does not execute smart communication is unnecessary, the power supply of the electronic key 2 is turned off, so that a standby current does not flow in the electric circuit in the electronic key 2, and the life of the battery 19 is extended accordingly. be able to. Even if the electronic key 2 is turned off during normal operation, the electronic key 2 is activated by the electric power wave Svc transmitted from the vehicle 1. Therefore, even if the electronic key 2 is suspended during normal operation, there is no problem during communication. Can be operated.

  (2) Since the electronic key system 3 is executed only several times a day, for example, the electronic key 2 is currently in a standby state waiting for communication execution for most of the day. Therefore, as in this example, if the communication control circuit 12 is disconnected from the battery 19 and the power of the electronic key 2 is turned off while the electronic key 2 is not performing communication, the electronic key 2 is turned off for a long time. Since it is not necessary to pass a standby current through the electronic key 2, it can be said that if the wireless power transmission system 18 of this example is applied to the electronic key system 3, it is very effective in extending the life of the battery 19.

  (3) The electronic key 2 is provided with a discharging circuit 26 that discharges the charging power of the charging circuit 21 when data transmission along smart communication is completed. For this reason, when data transmission of smart communication is completed, the communication control circuit 12 can be immediately returned to the original power-off state disconnected from the battery 19.

  (4) When the first switch 25 is turned on by the charging power of the charging circuit 21 and the communication control circuit 12 is electrically connected to the battery 19 and the electronic key 2 is turned on, the key receiver 15 receives at this time. If the received data is not regular data, the discharging circuit 26 discharges the charging power of the charging circuit 21 and immediately returns the communication control circuit 12 to the original power-off state. For this reason, even if the communication control circuit 12 is connected to the battery 19 due to noise and the electronic key 2 is turned on, the communication control circuit 12 can be immediately returned to the original power-off state after being disconnected from the battery 19. For this reason, a situation in which standby current flows in the electric circuit in the electronic key 2 does not occur in a situation where the communication that the electronic key 2 is activated due to noise is not executed, and the effect of extending the life of the battery 19 is enhanced. .

(5) Since the RF band is used for the request signal Srq, the request signal Srq can be skipped to a position far away from the vehicle 1.
Note that the embodiment is not limited to the configuration described so far, and may be modified as follows.

  The request signal Srq and the power radio wave Svc are not necessarily limited to the same frequency. For example, as shown in FIG. 7, for example, the request signal Srq is an LF (Low Frequency) band and the power radio wave Svc is an RF band. In addition, each may take a different frequency. In this case, the transmitters 8 and 9 include a dedicated transmission circuit (request transmission unit 41) for transmitting the LF request signal Srq and a dedicated transmission circuit (power transmission processing unit 20) for transmitting the electric power wave Svc. Are individually provided, and the key receiver 15 is used for LF reception. Then, by selectively operating these transmission circuits, the request signal Srq and the power radio wave Svc are transmitted at different frequencies, respectively, and the request signal Srq is transmitted by the LF key receiver 15 and the power radio wave Svc is received by the RF receiving antenna. This can be handled by accepting at 22.

  The frequency of the electric power radio wave Svc is not necessarily limited to RF, and other frequencies such as LF may be adopted. That is, the frequencies of the request signal Srq and the power radio wave Svc are not limited to RF and LF, and various frequencies can be adopted.

The receiving antenna 22 of the charging circuit 21 does not necessarily need to be provided as an antenna dedicated to charging, and for example, the antenna of the key receiver 15 may be shared.
The charging circuit 21 is not limited to the configuration including the diode 23 and the capacitor 24, and the circuit configuration is not particularly limited as long as the power radio wave Svc can be charged.

The discharge circuit 25 is not necessarily configured by the switch 27 and the resistor 28, and may have any configuration as long as the power of the charging circuit 21 can be discharged.
The discharge circuit 26 is not always necessary and may be omitted.

The various antennas possessed by the electronic key 2 are not necessarily provided individually for each function, and may be shared among a plurality of functions.
The electronic key system 3 is not necessarily limited to the key operation free system 6, and a wireless key system may be adopted. That is, the electronic key 2 is not limited to a bidirectional type capable of both data reception and data transmission, and may be a unidirectional type capable of only transmitting data by operating a button on the key. Further, both systems may be incorporated in one electronic key 2.

  The transistors used in the switches 25 and 27 are not necessarily limited to bipolar transistors, and field drop transistors (FETs) may be used. Further, the switches 25 and 25 are not necessarily limited to transistors, and other types of switches such as a switch contact that is switched by electromagnetic induction of a coil may be employed.

The communication terminal is not necessarily limited to the one that performs the data transmission operation, and may be a terminal that can execute only data reception as data communication, for example.
• Confirmation of whether the received data is normal is not limited to the method of judging by looking at the start bit at the beginning of the received data. For example, a method may be adopted in which it is determined whether or not the data itself can be read, or whether or not all data can be read within a certain time.

  The communication terminal is not necessarily limited to the electronic key 2 and the type thereof is not particularly limited as long as it is a terminal capable of data communication. Further, the data communication system is not necessarily limited to the electronic key system 3 (used in the vehicle 1), and may be any system that exchanges data wirelessly.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below together with their effects.
(1) In any one of Claims 1-3, it is provided with the data transmission / reception means which enables both data reception and data transmission, and when the said control circuit will be in a connection state with the said battery, the said data transmission / reception by the said battery The data receiving operation in the means is started and the data transmission operation from the data transmitting / receiving means is executed as a response to the received data while executing the data processing of the received data. According to this configuration, the communication terminal can be used as a terminal that can transmit and receive data.

  (2) In the technical idea (1), the data receiving antenna and the data transmitting antenna are individually provided as separate members. According to this configuration, it is possible to simplify the operation management of the antenna.

  (3) In any one of Claims 1-3, it is provided with the data transmission means which can perform data transmission operation | movement, and the said control circuit performs the data transmission operation in the said data transmission means with the said battery connected. According to this configuration, the communication terminal can be applied as a terminal for unidirectional communication that can only transmit data.

  (4) When a communication terminal executes data communication operation of at least one of data transmission and data reception with a communication device that is a communication partner, a control circuit that manages data communication in the communication terminal is a power source of the terminal In the data communication method for executing the data communication by operating by the power of the battery, the battery is normally electrically disconnected from the control circuit between the control circuit and the battery, and the control circuit is turned off. When the electronic key receives the power radio wave transmitted from the communication device with the antenna as a radio wave that can be converted into electric power, the power radio wave is charged by the charging unit, and the charge value is set to the set value. If it exceeds, the switch means is switched to a state where the battery and the control circuit are electrically connected, and the control circuit is turned on. It allows the data communication method for enabling data communication operation of the control circuit.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle as communication apparatus, 2 ... Electronic key as communication terminal, 12 ... Communication control circuit which comprises control circuit and data transmission / reception means, 15 ... Key receiver which comprises data transmission / reception means, 16 ... Data transmission / reception means Key transmitter, 19 ... battery, 21 ... charging circuit as charging means, 22 ... receiving antenna as antenna, 25 ... first switch as switching means, 26 ... discharging circuit as discharging means, 29 ... monitoring means Discharge circuit control unit as 30... Data confirmation unit as return means, Svc... Electric power radio wave, Vk... Threshold value as set value, Srq... Request signal as communication data.

Claims (4)

In the communication terminal that executes the data communication operation of at least one of data transmission and data reception by the control circuit that manages the execution operation of the data communication being operated by the power of the battery that it has,
Switch means provided between the control circuit and the battery, and normally disconnecting the battery from the control circuit and turning off the control circuit;
When a power radio wave transmitted from the outside is received by an antenna as a radio wave that can become electric power, the power radio wave is charged, and when the charge value exceeds a set value, the battery and the control circuit are electrically connected. And a charging means for enabling data communication operation of the control circuit by switching the switch means to power on the control circuit. Monitoring means for monitoring whether or not the data transmission operation by the control circuit that is powered on is completed;
Discharging means for returning the switch circuit to the original power-off state by discharging the power charged in the charging means to the outside when the data transmission operation is completed; The communication terminal according to claim 1, further comprising: Data transmission / reception means enabling both data reception and data transmission;
After connecting the control circuit to the battery by the charging, the data content of the communication data received by the data transmitting / receiving unit is confirmed, and if the communication data is not normal, the charging unit is forcibly forced by the discharging unit. 3. The communication terminal according to claim 2, further comprising return means for discharging and immediately returning the switch means to the original state. A control circuit that manages data communication is operated by the power of the battery that is the power source of the terminal, thereby communicating with a communication terminal that performs at least one data communication operation of data transmission and data reception as a communication partner of the communication terminal A data communication system comprising:
Switch means provided between the control circuit and the battery, and normally disconnecting the battery from the control circuit and turning off the control circuit;
When a power radio wave transmitted from the communication device is received by the antenna as a radio wave that can become electric power, the power radio wave is charged, and when the charge value exceeds a set value, the battery and the control circuit are electrically connected. A data communication system comprising: charging means for enabling data communication operation of the control circuit by switching the switch means to a connected state and powering on the control circuit.

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