JP2014078813A - On-vehicle device and vehicle locking/unlocking device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle device and a vehicle locking/unlocking device using the same used mainly for controlling to lock and unlock doors of vehicles capable of reducing power consumption.SOLUTION: A first switch circuit 22 is connected to a second switch circuit 23 via a fixed resistor 25 and a first antenna terminal P31 is disposed between the fixed resistor 25 and a second switch circuit 23. A control circuit 21 controls the first switch circuit 22 and the second switch circuit 23 to repeat turning ON/OFF during an oscillation period T31. During a resonance period T32, the control circuit 21 controls the first switch circuit 22 to turn OFF and the second switch circuit 23 to turn ON. During a power off period T33, the control circuit 21 controls both the first switch circuit 22 and the second switch circuit 23 to turn OFF. With this, an on-vehicle device 80 capable of reducing the power consumption with a simple configuration is achieved.

Description

  The present invention relates to an in-vehicle device that performs communication with a portable device of a user and unlocks / locks a vehicle door, and a vehicle locking / unlocking device using the same.

  2. Description of the Related Art In recent years, vehicle locking / unlocking devices that perform unlocking / locking of a vehicle door simply by a user carrying a portable device and approaching or leaving the vehicle have become widespread.

  The vehicle locking / unlocking device includes an in-vehicle antenna that transmits radio waves to a portable device and an in-vehicle device that outputs a predetermined signal to the in-vehicle antenna. In general, the in-vehicle device is arranged inside an instrument panel of the vehicle, and the in-vehicle antenna is arranged inside a door or door handle of the vehicle.

  Such a vehicle locking / unlocking device is required to save power, and therefore, an in-vehicle device capable of transmitting radio waves to a portable device with low power has been proposed.

  FIG. 3 is a diagram showing a circuit configuration of a conventional vehicle locking / unlocking device 20, and FIG. 4 is a diagram showing signal waveforms at internal terminals P01, P02, P03 and an antenna terminal P11 of the in-vehicle device 11. 4A shows the signal waveform of the internal terminal P01, FIG. 4B shows the signal waveform of the internal terminal P02, and FIG. 4C shows the signal waveform of the internal terminal P03. FIG. 4D shows a signal waveform at the antenna terminal P11.

  The vehicle locking / unlocking device 20 includes an in-vehicle device 11 and an in-vehicle antenna 12 connected to the in-vehicle device 11.

  The in-vehicle device 11 includes a control circuit 1, a first switch circuit 2, a second switch circuit 3, a third switch circuit 4, a fixed resistor 5, and an internal antenna 6.

  The control circuit 1 is composed of a semiconductor element such as a microcomputer. The first switch circuit 2, the second switch circuit 3, and the third switch circuit 4 are configured by, for example, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Further, the internal antenna 6 has a resonance frequency between 300 MHz and 400 MHz, for example.

  The control circuit 1 is connected to an internal terminal P01 which is a gate of the first switch circuit 2, an internal terminal P02 which is a gate of the second switch circuit 3, and an internal terminal P03 which is a gate of the third switch circuit 4. The first switch circuit 2, the second switch circuit 3, and the third switch circuit 4 are switched on / off. The control circuit 1 is connected to the internal antenna 6.

  The source of the first switch circuit 2 is connected to the drain of the second switch circuit 3. A branch is provided between the source of the first switch circuit 2 and the drain of the second switch circuit 3, and is connected to one end of the fixed resistor 5. The other end of the fixed resistor 5 branches into two, one is connected to the drain of the third switch circuit 4 and the other is connected to the antenna terminal P11. The drain of the first switch circuit 2 is connected to the battery potential, and the source of the second switch circuit 3 is connected to the ground of the in-vehicle device 11.

  The antenna terminal P11 is connected to the vehicle-mounted antenna 12. Here, the in-vehicle antenna 12 is configured as a series resonance circuit in which the coil 7 and the capacitor 8 are connected in series. The resonance frequency of the in-vehicle antenna 12 is, for example, an LF (Low Frequency) band between 100 kHz and 300 kHz.

  The vehicle-mounted device 11 configured as described above performs intermittent transmission of the request signal Sg1 through the vehicle-mounted antenna 12 at a cycle T1, as shown by the signal waveform of the antenna terminal P11 in FIG.

  Here, the period T1 includes an oscillation period T11, a resonance period T12, and a power interruption period T13.

  In the oscillation period T11, the first switch circuit 2 and the second switch circuit 3 repeat ON / OFF. Here, when the first switch circuit 2 is ON, the second switch circuit 3 is OFF, and when the first switch circuit 2 is OFF, the second switch circuit 3 is ON. This ON / OFF switching cycle is performed at, for example, 125 kHz, and a 125 kHz request signal Sg <b> 1 is transmitted from the vehicle-mounted antenna 12. At this time, the third switch circuit 4 is OFF.

  In the resonance period T12, the first switch circuit 2 and the second switch circuit 3 are OFF, and the third switch circuit 4 is ON. Thereby, since the closed loop of a resonance circuit can be formed with the 3rd switch circuit 4, the coil 7, and the capacitor | condenser 8, the fall of the amplitude of request signal Sg1 can be suppressed in the state which suppressed the electric power consumption of the vehicle equipment 11. FIG.

  In the disconnection period T13, the first switch circuit 2, the second switch circuit 3, and the third switch circuit 4 are all turned OFF. As a result, the closed loop of the resonance circuit is disconnected, so that the amplitude of the request signal Sg1 can be rapidly reduced.

  In other words, in the conventional in-vehicle device 11, the third switch circuit 4, the coil 7, and the capacitor 8 form a closed loop of the resonance circuit in the resonance period T <b> 12, thereby suppressing the power consumption of the in-vehicle device 11. I was trying.

  When the request signal Sg1 is transmitted from the in-vehicle device 11 configured as described above to a portable device (not shown), the portable device determines whether the request signal Sg1 is a predetermined signal. If the request signal Sg1 is a predetermined signal, the unlock signal Sg2 is transmitted to the vehicle-mounted device 11. When the unlock signal Sg2 is received via the internal antenna 6 and the control circuit 1 determines that it matches the predetermined signal, the control circuit 1 controls the unlocking of the door of the vehicle.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP 2009-135859 A

  However, from the viewpoint of cost reduction or operation stability, it is desirable to realize low power consumption with a simpler configuration.

  This invention respond | corresponds to such a request, and it aims at providing the vehicle-mounted apparatus and vehicle locking / unlocking apparatus using the same which suppressed power consumption by simple structure.

  To achieve the above object, according to the present invention, the first switch circuit is connected to the second switch circuit via a fixed resistor, and the first antenna terminal is disposed between the fixed resistor and the second switch circuit. . In addition, the control circuit controls the first switch circuit and the second switch circuit to repeat ON / OFF during the oscillation period, and the control circuit turns off the first switch circuit and turns on the second switch circuit during the resonance period. In the power interruption period T33, the control circuit controls to turn off both the first switch circuit and the second switch circuit to configure the in-vehicle device.

  As described above, according to the present invention, the first switch circuit is connected to the second switch circuit via the fixed resistor, and the first antenna terminal is disposed between the fixed resistor and the second switch circuit. In addition, the control circuit controls the first switch circuit and the second switch circuit to repeat ON / OFF during the oscillation period, and the control circuit turns off the first switch circuit and turns on the second switch circuit during the resonance period. In the power interruption period T33, the control circuit controls the first switch circuit and the second switch circuit to be turned off to configure the vehicle-mounted device. As a result, it is possible to provide an in-vehicle device that suppresses power consumption with a simple configuration without using the third switch circuit.

The figure which shows the circuit structure of the vehicle locking / unlocking apparatus by one embodiment of this invention. The figure which shows the signal waveform of the vehicle equipment used for the vehicle locking / unlocking device The figure which shows the circuit structure of the conventional vehicle locking / unlocking apparatus. The figure which shows the signal waveform of the vehicle equipment used for the vehicle locking / unlocking device

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

(Embodiment)
FIG. 1 is a diagram showing a circuit configuration of a vehicle locking / unlocking device 100 according to an embodiment of the present invention, and FIG. 2 is a diagram showing signal waveforms at internal terminals P21 and P22 and a first antenna terminal P31 of an in-vehicle device 80. is there. 2A shows the signal waveform of the internal terminal P21, FIG. 2B shows the signal waveform of the internal terminal P22, and FIG. 2C shows the signal waveform of the first antenna terminal P31. .

  The vehicle locking / unlocking device 100 includes an in-vehicle device 80 and an in-vehicle antenna 90 connected to the in-vehicle device 80. The in-vehicle device 80 is arranged inside the instrument panel of the vehicle, and the in-vehicle antenna 90 is arranged inside the door or door handle of the vehicle.

  Here, the in-vehicle device 80 includes a control circuit 21, a first switch circuit 22, a second switch circuit 23, a fixed resistor 25, and an internal antenna 26.

  The control circuit 21 is composed of a semiconductor element such as a microcomputer, and the first switch circuit 22 and the second switch circuit 23 are composed of, for example, a power MOSFET (Metal Oxide Field Effect Transistor), and the internal antenna 26 is, for example, from 300 MHz. It has a resonance frequency between 400 MHz.

  In the case where power MOSFETs are used as the first switch circuit 22 and the second switch circuit 23, either an n-channel MOSFET or a p-channel MOSFET may be used. In the case of using an n-channel MOSFET, the potential of the drain is increased with respect to the source and the signal is turned on when a signal having a potential of HI is applied to the gate, and turned off when the signal of a potential of LO is applied. In the case of using a p-channel MOSFET, the drain potential is increased with respect to the source, and the signal is turned on when a signal having an LO potential is applied to the gate, and turned off when a signal having an HI potential is applied.

  The following description will be made assuming that n-channel MOSFETs are used as the first switch circuit 22 and the second switch circuit 23.

  The control circuit 21 is connected to the internal terminal P21 which is the gate of the first switch circuit 22 and the internal terminal P22 which is the gate of the second switch circuit 23, and the first switch circuit 22 and the second switch circuit 23 are connected. Switch ON / OFF. The control circuit 21 is connected to the internal antenna 26.

  Here, the source of the first switch circuit 22 is connected to the drain of the second switch circuit 23 via the fixed resistor 25. The first antenna terminal P31 is disposed between the fixed resistor 25 and the drain of the second switch circuit 23. The drain of the first switch circuit 22 is connected to the battery potential, and the source of the second switch circuit 23 is connected to the ground of the in-vehicle device 80. Further, a second antenna terminal P32 is disposed between the source of the second switch circuit 23 and the ground.

  The first antenna terminal P31 and the second antenna terminal P32 are connected to the vehicle-mounted antenna 90. Here, the coil 27 and the capacitor 28 are connected in series, and both ends thereof are connected to the first antenna terminal P31 and the second antenna terminal P32.

  The coil 27 and the capacitor 28 form a series resonance circuit, and the resonance frequency is, for example, an LF (Low Frequency) band between 100 kHz and 300 kHz.

  The in-vehicle device 80 configured as described above performs intermittent transmission of the request signal Sg21 at a predetermined cycle T21 via the in-vehicle antenna 90 as shown by the signal waveform of the first antenna terminal P31 in FIG. Do.

  Here, the period T21 includes an oscillation period T31, a resonance period T32, and a power interruption period T33.

  In the oscillation period T31, the first switch circuit 22 and the second switch circuit 23 repeat ON / OFF. Here, when the first switch circuit 22 is ON, the second switch circuit 23 is OFF, and when the first switch circuit 22 is OFF, the second switch circuit 23 is ON. This ON / OFF switching cycle is performed at, for example, 125 kHz, and a 125 kHz request signal Sg21 is transmitted from the vehicle-mounted antenna 90.

  As shown in FIG. 2C, in the oscillation period T31, the amplitude of the signal waveform of the request signal Sg21 gradually increases. Although the envelope L1 is attached to the outer shape of the request signal Sg21, the envelope L1 gradually increases during the oscillation period T31 and reaches a potential of + V.

  In the resonance period T32, the first switch circuit 22 is OFF and the second switch circuit 23 is ON. Thereby, since the closed loop of the resonance circuit can be formed by the second switch circuit 23, the coil 27, and the capacitor 28, the decrease in the amplitude of the request signal Sg21 can be suppressed while the power consumption of the in-vehicle device 80 is suppressed. Here, by connecting the in-vehicle antenna 90 directly to both ends of the second switch circuit 23, it is possible to suppress the closed-loop resistance loss of the resonance circuit configured by the second switch circuit 23 and the in-vehicle antenna 90. Here, the first antenna terminal P31 and the second antenna terminal P32 are arranged at both ends of the second switch circuit 23, respectively, and the vehicle-mounted antenna 90 is directly connected to the first antenna terminal P31 and the second antenna terminal P32. Connected. By configuring in this way, a closed loop of the resonance circuit constituted by the second switch circuit 23 and the vehicle-mounted antenna 90 can be implemented with a small resistance loss.

  In the disconnection period T33, both the first switch circuit 22 and the second switch circuit 23 are turned off. As a result, the closed loop of the resonance circuit is disconnected, so that the amplitude of the request signal Sg21 can be drastically reduced.

  That is, the in-vehicle device 80 can suppress the power consumption of the in-vehicle device 80 by forming a closed loop of the resonance circuit with the second switch circuit 23, the coil 27, and the capacitor 28 in the resonance period T32. .

  The in-vehicle device 80 has two configurations of the first switch circuit 22 and the second switch circuit 23 as the switch circuit, and can be implemented at a low cost with a simple configuration.

  When the request signal Sg21 is transmitted from the vehicle-mounted device 80 configured as described above to a portable device (not shown) at a transmission frequency of, for example, 125 kHz, the portable device determines whether the request signal Sg21 is a predetermined signal. If the request signal Sg21 is a predetermined signal, the unlock signal Sg22 is transmitted to the in-vehicle device 80 at a transmission frequency of 315 MHz, for example. When the unlock signal Sg22 is received via the internal antenna 26 and the control circuit 21 determines that it matches the predetermined signal, the control circuit 21 controls the unlocking of the door of the vehicle.

  Thus, according to the present embodiment, the first switch circuit 22 is connected to the second switch circuit 23 via the fixed resistor 25, and the first switch circuit 22 is connected between the fixed resistor 25 and the second switch circuit 23. The antenna terminal P31 is disposed. Further, in the oscillation period T31, the control circuit 21 performs control so that the first switch circuit 22 and the second switch circuit 23 repeat ON / OFF, and in the resonance period T32, the control circuit 21 turns off the first switch circuit 22. The second switch circuit 23 is controlled to be turned on, and the control circuit 21 performs control so that both the first switch circuit 22 and the second switch circuit 23 are turned off in the power interruption period T33. Thereby, the vehicle equipment 80 which suppressed power consumption with a simple structure can be provided.

  Further, the in-vehicle device 80 includes a first antenna terminal P31 and an antenna terminal P32, and an in-vehicle antenna 90 having a series resonance circuit composed of a coil 27 and a capacitor 28 is connected between the first antenna terminal P31 and the antenna terminal P32. Thus, the vehicle locking / unlocking device 100 is configured. With this configuration, the in-vehicle antenna 90 is directly connected to both ends of the second switch circuit 23, thereby suppressing the closed-loop resistance loss of the resonance circuit configured by the second switch circuit 23 and the in-vehicle antenna 90. sell.

  The vehicle-mounted device and the vehicle locking / unlocking apparatus using the same according to the present invention have an advantageous effect of suppressing power consumption with a simple configuration, and are mainly useful for controlling locking / unlocking of a vehicle door.

DESCRIPTION OF SYMBOLS 21 Control circuit 22 1st switch circuit 23 2nd switch circuit 25 Fixed resistance 26 Internal antenna 27 Coil 28 Capacitor 80 Vehicle-mounted machine 90 Vehicle-mounted antenna 100 Vehicle locking / unlocking device

Claims (2)

A first switch circuit; a second switch circuit electrically connected to the first switch circuit; a control circuit for controlling ON / OFF of the first switch circuit and the second switch circuit; A fixed resistor disposed between the first switch circuit and the second switch circuit, and a first antenna terminal disposed between the fixed resistor and the second switch circuit,
A request signal is output at a predetermined cycle from the first antenna terminal,
The period is composed of an oscillation period, a resonance period, and a power interruption period.
In the oscillation period, the control circuit controls the first switch circuit and the second switch circuit to repeat ON / OFF, and in the resonance period, the control circuit turns off the first switch circuit and turns on the first switch circuit. A vehicle-mounted device that controls to turn on the second switch circuit, and that the control circuit controls to turn off both the first switch circuit and the second switch circuit during the disconnection period. The vehicle-mounted device according to claim 1 and a vehicle-mounted antenna connected to the vehicle-mounted device,
The in-vehicle device further includes a second antenna terminal between a path where the second switch circuit is grounded, and the in-vehicle antenna is connected between the first antenna terminal and the second antenna terminal. Vehicle locking / unlocking device.

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