VEHICLE DOOR HANDLE DRIVING DEVICE AND VEHICLE COMMUNICATION APPARATUS

A vehicle door handle driving device connected to an antenna and a DC driving detection member capable of detecting approach or touch of a person, which are connected in parallel, through first and second connection wires, wherein the first connection wire is constantly connected to a first positive DC power supply, and the second connection wire is connected to a ground for a period during which the antenna is not driven, the vehicle door handle driving device includes: a booster capacitor whose one terminal is connected to the first DC power supply; and an inverter connected to the other terminal of the booster capacitor, connected to a second positive DC power supply and the ground, generating an AC voltage having a resonance frequency of the antenna, and outputting the generated AC voltage to the first and second connection wires.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application 2015-123575, filed on Jun. 19, 2015, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates to a vehicle door handle driving device and a vehicle communication apparatus.

BACKGROUND DISCUSSION

Japanese Patent No. 5589870 (Reference 1) and JP2014-17701A (Reference 2) disclose various vehicle door handle driving devices. The vehicle door handle driving device (ECU or driving ECU) uses two electric wires (connection wires) to be connected to a door handle (vehicle-mounted device or module) including a detection member (person detection IC or sensor IC) and an antenna, and these two electric wires are used for the power supply (driving) of the antenna, for the power supply of the detection member, and for the outputting of the detection signal. Particularly, in order to prevent the power supply to the detection member from being blocked for a period during which the antenna is driven, it has been suggested that a resonance voltage of the antenna is used.

However, in References 1 and 2, the resonance voltage of the antenna is used to supply the power to the detection member, and thus, it is necessary to set the resonance voltage to be equal to or less than a rated voltage of the detection member. Accordingly, it is necessary to increase the size of the antenna as the Q factor of the antenna may not be increased.

SUMMARY

Thus, a need exists for a vehicle door handle driving device and a vehicle communication apparatus which are not suspectable to the drawback mentioned above.

A vehicle door handle driving device according to an aspect of this disclosure is electrically connected to an antenna and a DC driving detection member capable of detecting approach or touch of a person, which are mounted on a door handle and are connected in parallel, through a first connection wire and a second connection wire. The first connection wire is constantly connected to a first positive DC power supply, and the second connection wire is connected to a ground for a period during which the antenna is not driven. The vehicle door handle driving device includes: a booster capacitor whose one terminal is connected to the first DC power supply; and an inverter that is connected to the other terminal of the booster capacitor, is connected to a second positive DC power supply and the ground, generates an AC voltage having a resonance frequency of the antenna, and outputs the generated AC voltage to the first connection wire and the second connection wire through the booster capacitor.

A vehicle communication apparatus according to another aspect of this disclosure includes: a first connection wire and a second connection wire; an antenna; a detection member that includes a power terminal and a ground terminal which are respectively connected to the first connection wire and the second connection wire, a detection output terminal which is connected to the first connection wire to output a negative detection signal indicating whether or not approach or touch of a person is detected, an antenna driving detection terminal which is connected to the first connection wire, and an antenna driving detection unit which detects a driving state of the antenna based on a voltage input to the antenna driving detection terminal; a DC cut capacitor whose both terminals are respectively connected to the detection output terminal and the antenna driving detection terminal; a passive element whose both terminals are respectively connected to the detection output terminal and the ground terminal; and the vehicle door handle driving device that further includes a lock and unlock controller which issues a lock or unlock command of a vehicle door based on the detection signal.

DETAILED DESCRIPTION

First Embodiment

Hereinafter, a vehicle door handle driving device and a vehicle communication apparatus according to a first embodiment will be described. The present embodiment is a smart entry (registered trademark) system that locks and unlocks a vehicle door through wireless communication with a portable device carried by a user of a vehicle.

As shown inFIG. 1, an outside door handle2is provided at a door outer panel1constituting the vehicle door. The outside door handle2extends in forward and backward directions of the vehicle, and is attached to the door outer panel1at two front and rear portions thereof. A recess1ais inwardly formed in the door outer panel1so as to face the outside door handle2. Thus, it is possible to allow a person to easily hold a substantially central portion of the outside door handle2with their hand.

The outside door handle2is formed by molding, for example, a resin material into a hollow shape having an inner space. Detection areas capable of detecting approach or touch of the person are formed on an outer wall surface of the outside door handle2. That is, a lock detection area3capable of detecting approach or touch of the hand of the person who intends to lock the vehicle door is formed on an outer wall surface of a front side of the outside door handle2. An unlock detection area4capable of detecting approach or touch of the hand of the person who intends to unlock the vehicle door is formed on an outer wall surface of an intermediate portion as a holding portion of the outside door handle2. Within the outside door handle2, a lock sensor electrode5which is made of, for example, a metal plate and has a substantially strip shape is accommodated close to a surface separated from the door outer panel1so as to correspond to the lock detection area3and an unlock sensor electrode6which is made of, for example, a metal plate and has a substantially strip shape is accommodated close to the door outer panel1so as to correspond to the unlock detection area4. The unlock sensor electrode6is formed so as to be greater than the lock sensor electrode5.

Within the outside door handle2, a module10which is electrically connected to the lock sensor electrode5and the unlock sensor electrode6is accommodated.

Hereinafter, an electrical configuration of the present embodiment will be described.

As shown inFIG. 2, a driving ECU50as the vehicle door handle driving device is connected to one end of a first electric wire W1as a first connection wire at a first controller-side terminal T11, and the other end of the first electric wire W1is connected to a first module-side terminal T21of the module10. The driving ECU50is connected to one end of a second electric wire W2as a second connection wire at a second controller-side terminal T12, and the other end of the second electric wire W2is connected to a second module-side terminal T22of the module10. That is, the driving ECU50and the module10are connected through two wires of the first and second electric wires W1and W2. The driving ECU50and the module10together with the first and second electric wires W1and W2constitute the vehicle communication apparatus100.

The driving ECU50includes a controller51which includes, for example, a microcomputer as a main member. The controller51includes a lock and unlock controller51a, and a power supply51b. The driving ECU50includes a diode52whose anode is connected to a battery +B as a first DC power supply, and a first switch SW1which is connected to a cathode of the diode52. The driving ECU50includes a constant voltage circuit53as a second DC power supply whose one end is similarly connected to the cathode of the diode52. The constant voltage circuit53generates an antenna driving voltage Vant (≦VB) whose voltage fluctuation is controlled based on a battery voltage VB supplied from the battery +B. The driving ECU50includes a second switch SW2and a third switch SW3connected to the other end of the constant voltage circuit53in series, and a fourth switch SW4and a fifth switch SW5connected to the other end of the constant voltage circuit53in series so as to be connected to the second and third switches in parallel. The third switch SW3and the fifth switch SW5are grounded.

The driving ECU50includes a sensor detection resistor54whose one end is connected to the first switch SW1. The other end of the sensor detection resistor54is connected to an anode of a backflow prevention diode55as a diode, and a cathode of the backflow prevention diode55is connected to the first controller-side terminal T11(first electric wire W1). The driving ECU50includes a booster capacitor56whose one terminal56ais connected to the cathode of the backflow prevention diode55through a resistor57. The other terminal56bof the booster capacitor56is connected to a connected portion of the second switch SW2and the third switch SW3. A sensor detection circuit59is connected between both terminals of the sensor detection resistor54. The sensor detection circuit59obtains a voltage Vs between both the terminals of the sensor detection resistor54. A connected portion of the fourth switch SW4and the fifth switch SW5is connected to the second controller-side terminal T12(second electric wire W2) through a resistor58.

Here, the lock and unlock controller51aof the controller51monitors the voltage Vs obtained in the sensor detection circuit59. Meanwhile, the power supply51boperates to switch the first to fifth switches SW1to SW5. Specifically, the power supply51bbasically sets the first switch SW1to be constantly in an ON state. Thus, the first controller-side terminal T11(first electric wire W1) is constantly connected to the battery +B through the backflow prevention diode55and the sensor detection resistor54. The power supply51bgenerates a square wave voltage VP having an amplitude double that of the antenna driving voltage Vant as an AC voltage by alternately switching between the ON and OFF states of the second and fifth switches SW2and SW5and the ON and OFF states of the third and fourth switches SW3and SW4(by allowing the polarities of the switches to be opposite to one another). The square wave voltage VP is output to the first controller-side terminal T11(first electric wire W1) through the booster capacitor56and the resistor57and is output to the second controller-side terminal T12(second electric wire W2) through the resistor58. The second to fifth switches SW2to SW5constitute an inverter INV realized using a so-called H bridge circuit. For a period during which the square wave voltage VP is not generated, the power supply51bsets the second to fourth switches SW2to SW4to be in the OFF state, and sets the fifth switch SW5to be in the ON state. In this case, the second controller-side terminal T12(second electric wire W2) is grounded.

In the module10, an antenna resonance capacitor11whose one end is connected to the first module-side terminal T21is provided, and an antenna coil12whose one end is connected to the other end of the antenna resonance capacitor11is provided. The other end of the antenna coil12is connected to the second module-side terminal T22. The antenna resonance capacitor11and the antenna coil12constitute an LF antenna21as an antenna, and constitute an LC serial resonance circuit having a resonance frequency f1. Accordingly, if an AC voltage (square wave voltage) having a frequency matching the resonance frequency f1is supplied from the driving ECU50through the first and second electric wires W1and W2, the antenna coil12is driven, and a radio signal is output from the antenna coil12. The radio signal is, for example, an inquiry signal (request signal) of the portable device carried by the user of the vehicle, and the portable device that has received the inquiry signal transmits a signal having a unique ID code.

A sensor IC30as a detection member is provided in the module10. The sensor IC30is connected to the lock sensor electrode5and the unlock sensor electrode6at a lock detection input terminal31and an unlock detection input terminal32, respectively, and is connected to the first module-side terminal T21at a detection signal output terminal33.

The sensor IC30includes a lock and unlock detection unit30aconstituting a known electrostatic sensor together with the lock sensor electrode5or the unlock sensor electrode6, and supplies power to the lock sensor electrode5and the unlock sensor electrode6through the lock detection input terminal31and the unlock detection input terminal32by means of the lock and unlock detection unit30a. The lock and unlock detection unit30adetects that the hand of the person approaches or touches the lock detection area3or the unlock detection area4by respectively detecting electrostatic capacitance changes between the lock sensor electrode5and the door outer panel1and between the unlock sensor electrode6and the door outer panel. The lock and unlock detection unit30aoutputs a lock detection signal as a negative detection signal indicating whether or not the detection is performed to the first module-side terminal T21(first electric wire W1) from the detection signal output terminal33. Specifically, the lock and unlock detection signal30aincludes a known switching member, and generates and outputs, for example, a lock detection signal and an unlock detection signal by causing voltage drop in the supply voltage of the driving ECU50with different cycles.

If the lock detection signal or the unlock detection signal is output to the first controller-side terminal T11through the first electric wire W1, as much current flows to the sensor detection resistor54as the voltage drop, and thus, the voltage drop is obtained in the sensor detection circuit59, as the voltage Vs between both the terminals of the sensor detection resistor54. The lock and unlock controller51adetects the lock detection signal or the unlock detection signal based on the monitored voltage Vs. The lock and unlock controller51aissues a lock command of the vehicle door through the detection of the lock detection signal and issues an unlock command of the vehicle door through the detection of the unlock detection signal.

The sensor IC30is connected to one end of the resistor41at a power terminal34, and the other end of the resistor41is connected to the first module-side terminal T21. The sensor IC30is connected to the second module-side terminal T22at a ground terminal35. A smoothing capacitor42is connected between the power terminal34and the ground terminal35.

Accordingly, for example, for a period during which the square wave voltage VP is not generated (for a period during which the inverter INV is not driven), the power terminal34is connected to the battery +B through the first electric wire W1and the ground terminal35is grounded through the second electric wire W2, so that the sensor IC30is driven by the battery voltage VB supplied from the driving ECU50. Meanwhile, for a period during which the square wave voltage VP is generated (for a period during which the inverter INV is driven), in the sensor IC30, the power terminal34is connected to the battery +B through the first electric wire W1and is connected to the inverter INV through the first electric wire W1and the booster capacitor56and the ground terminal35is connected to the inverter INV through the second electric wire W2. Thus, the sensor IC30is driven by a voltage from the driving ECU50obtained by raising a DC component of the square wave voltage VP by the battery +B.

That is, the LF antenna21and the sensor IC30are electrically connected to the inverter INV (driving ECU50) in a state in which these members are connected in parallel. The booster capacitor56serves to raise a DC component for a period during which the LF antenna21is driven by storing power for a period during which the sensor IC30is driven. The capacitance of the booster capacitor56is set to be (for example, about a hundred times or more) greater than the capacitance of the antenna resonance capacitor11, and thus, boosting to a specified voltage is realized.

The sensor IC30is connected to one end of the resistor43as a passive element at an antenna driving detection terminal36, and the other end of the resistor43is connected to the ground terminal35. In the sensor IC30, a DC cut capacitor44is connected between the detection signal output terminal33and the antenna driving detection terminal36. Accordingly, for a period during which the square wave voltage VP matching the resonance frequency f1is supplied from the driving ECU50through the first and second electric wires W1and W2(that is, for a period during which the LF antenna21is driven), a DC component is removed in the DC cut capacitor44, and a voltage divided by the DC cut capacitor44and the resistor43is supplied to the antenna driving detection terminal36.

The sensor IC30includes an antenna driving detection unit30b, and detects the voltage divided by the DC cut capacitor44and the resistor43by means of the antenna driving detection unit30b. The antenna driving detection unit30bdetermines whether or not the LF antenna21is driving based on a level (root mean square value) of the voltage divided by the DC cut capacitor44and the resistor43. Specifically, the antenna driving detection unit30bincludes, for example, a comparator, and determines that the LF antenna21is driving in a case where the level of the voltage exceeds a preset threshold.

The sensor IC30includes a stop controller30c, and obtains the determination result in the antenna driving detection unit30bby means of the stop controller30c. In a case where it is determined that the LF antenna21is driving, the stop controller30cstops the function of the sensor IC30. Specifically, the stop controller30ctransmits a stop command to the lock and unlock detection unit30a, and stops outputting the detection signal from the detection signal output terminal33. Alternatively, the stop controller30cmay stop supplying the power to the lock sensor electrode5and the unlock sensor electrode6by the lock and unlock detection unit30a. Alternatively, the stop controller30cmay stop the entire function of the lock and unlock detection unit30a.

In a case where it is determined that the LF antenna21is not driven by the antenna driving detection unit30b, the stop controller30creleases the function stoppage of the sensor IC30(resumes the function of the sensor IC30).

Hereinafter, an aspect in which the power is supplied to the module10by the power supply51b(driving ECU50) will be described.

As shown inFIG. 3A, the power supply51bsets the first switch SW1to be constantly in the ON state as described above. That is, the first controller-side terminal T11(first electric wire W1) is constantly connected to the battery +B through the backflow prevention diode55and the sensor detection resistor54.

As shown inFIGS. 3B to 3E, for a period during which the sensor IC30is driven (for a period during which the square wave voltage VP is not generated), the power supply51bsets the second to fourth switches SW2to SW4to be in the OFF state, and sets the fifth switch SW5to be in the ON state. Accordingly, the second controller-side terminal T12(second electric wire W2) is grounded. Accordingly, the power terminal34is connected to the battery +B through the resistor41and the first module-side terminal T21(first electric wire W1) and the ground terminal35is grounded through the second module-side terminal T22(second electric wire W2), so that the battery voltage VB of the battery +B is supplied to the sensor IC30through the first and second electric wires W1and W2.

Meanwhile, for a period during which the LF antenna21is driven, the LF antenna is switched between an oscillation period and a non-oscillation period at a frequency which is sufficiently smaller than the resonance frequency f1. For a period during which the LF antenna oscillates (for a period during which the square wave voltage VP is generated), the power supply51bgenerates a square wave voltage VP having a resonance frequency f1having an amplitude double that of the antenna driving voltage Vant by alternately switching the ON and OFF states of the second and fifth switches SW2and SW5and the ON and OFF states of the third and fourth switches SW3and the SW4with the resonance frequency f1.

Here, the connected portion of the second and third switches SW2and SW3is connected to the first controller-side terminal T11(first electric wire W1) through the booster capacitor56, and thus, the LF antenna21is driven by a voltage obtained by raising a DC component of the square wave voltage VP by the battery +B. In addition, for a period during which the LF antenna21oscillates, the sensor IC30is driven by a voltage obtained by raising the DC component of the square wave voltage VP by the battery +B and smoothing the voltage whose DC component is raised in the capacitor42.

Meanwhile, for a period during which the LF antenna does not oscillate (for a period during which the square wave voltage VP is not generated), the power supply51bsets the second to fourth switches SW2to SW4to be in the OFF state, and sets the fifth switch SW5to be in the ON state. Accordingly, the power terminal34is connected to the battery +B through the resistor41and the first module-side terminal T21(first electric wire W1) and the ground terminal35is grounded through the second module-side terminal T22(second electric wire W2), so that the battery voltage VB of the battery +B is supplied to the sensor IC30through the first and second electric wires W1and W2.

The oscillation period and non-oscillation period of the LF antenna21correspond to an ON period and an OFF period of information signal (logics “1” and “0”), and the above-described inquiry signal is generated and transmitted by combinations thereof.

As stated above, according to the present embodiment, the following effects are obtained.

(1) In the present embodiment, the first electric wire W1is constantly connected to the battery +B. Accordingly, for example for a period during which the inverter INV is not driven (that is, for a period during which the LF antenna21is not driven), the second electric wire W2is grounded (is connected to a ground), and thus, the battery voltage VB (DC voltage) of the battery +B is supplied to the sensor IC30through the first and second electric wires W1and W2. Meanwhile, for a period during which the inverter INV is driven (that is, for a period during which the LF antenna21is driven), the square wave voltage VP having the resonance frequency f1of the LF antenna21is output to the first electric wire W1and the second electric wire W2through the booster capacitor56. Accordingly, the voltage obtained by raising the DC component of the square wave voltage VP having the resonance frequency f1of the LF antenna21by the battery voltage VB of the battery +B is supplied to the sensor IC30through the first and second electric wires W1and W2.

As mentioned above, the power is supplied to the sensor IC30irrespective of whether or not the LF antenna21is driven. In this case, the power can be supplied to the sensor IC30without using the resonance voltage especially for a period during which the LF antenna21is driven, and thus, the resonance voltage can be set without being restricted to a rated voltage of the sensor IC30. Thus, the size of the LF antenna21can be further reduced as the Q factor of the LF antenna21increases.

It is possible to further improve mountability thereof as the size of the LF antenna21is reduced. Alternatively, since it is not necessary to increase the size of the LF antenna21, adopt the sensor IC30having a high rated voltage, or separately provide a circuit element (for example, a diode having a high breakdown voltage) for supplying power at the resonance voltage, it is possible to achieve low cost.

The resonance voltage can be increased without being restricted to the rated voltage of the sensor IC30, and thus, it is possible to increase the output of the LF antenna21.

(2) In the present embodiment, it is assumed that for a period during which the inverter INV is driven (that is, for a period during which the LF antenna21is driven), the one terminal56aof the booster capacitor56becomes the voltage obtained by raising the DC component of the square wave voltage VP having the resonance frequency f1of the LF antenna21by the battery voltage VB of the battery +B. Even in this case, it is possible to suppress the backflow of current toward the battery +B by the backflow prevention diode55.

(3) In the present embodiment, for a period during which the LF antenna21is driven but does not oscillate, the power supply51b(driving ECU50) sets the fifth switch SW5to be in the ON state, and grounds the second electric wire W2(connects the second electric wire to the ground). Accordingly, even for a period during which the LF antenna21is driven, if the LF antenna does not oscillate, it is possible to supply the battery voltage VB (DC voltage) of the battery +B to the sensor IC30through the first and second electric wires W1and W2. Thus, for example, in a case where the sensor IC30has a function of changing into a so-called sleep state in which the sensor IC waits in a power saving state by temporarily stopping the operation thereof at the time of power shortage, it is possible to prevent the changing into the sleep state.

(4) In the present embodiment, the antenna driving detection terminal36is connected to the first electric wire W1(power terminal34) through the DC cut capacitor44, and is connected to the second electric wire W2(ground terminal35) through the resistor43. Accordingly, for example, for a period during which the inverter INV is not driven (that is, the LF antenna21is not driven), the voltage supplied to the antenna driving detection terminal36becomes zero. Therefore, if the lock detection signal or the unlock detection signal (detection signal) is output from the detection signal output terminal33, the detection signal is output to the first electric wire W1in a state in which the detection signal is blocked from flowing to the ground by the DC cut capacitor44. The lock and unlock controller51a(driving ECU50) can appropriately issue a lock or unlock command of the vehicle door based on the lock or unlock detection signal.

Meanwhile, for a period during which the inverter INV is driven (that is, for a period during which the LF antenna21is driven), the square wave voltage VP having the resonance frequency f1of the LF antenna21is output to the first electric wire W1and the second electric wire W2through the booster capacitor56. Accordingly, AC current flows to the DC cut capacitor44and the resistor43, and thus, as much of the voltage as the voltage drop in the resistor43is supplied to the antenna driving detection terminal36. Therefore, the antenna driving detection unit30bcan appropriately detect a driving state of the LF antenna21. In this case, particularly, the resonance voltage can be set without being restricted to the rated voltage of the antenna driving detection unit30b(sensor IC30) by detecting the driving state of the LF antenna21without using the resonance voltage especially for a period during which the LF antenna21is driven. Thus, the size of the LF antenna21can be further reduced as the Q factor of the LF antenna21increases.

It is possible to further improve mountability thereof as the size of the LF antenna21is reduced. Alternatively, since it is not necessary to increase the size of the LF antenna21, adopt the antenna driving detection unit30b(sensor IC30) having a high rated voltage, or separately provide a circuit element (for example, a diode having a high breakdown voltage) for using the resonance voltage, it is possible to achieve low cost.

The resonance voltage can be increased without being restricted to the rated voltage of the sensor IC30, and thus, it is possible to increase the output of the LF antenna21.

(5) In the present embodiment, even for a period during which the LF antenna21is driven, the power can be supplied to the sensor IC30through a passage which is constantly connected to the battery +B, and thus, it is possible to simplify the circuit configuration of the module10(outside door handle2) and it is possible to achieve low cost. Even for a period during which the LF antenna21is driven, the power can be supplied to the sensor IC30. Accordingly, for example, it is not necessary to increase the capacitance of the smoothing capacitor42for securing the power, and thus, it is possible to achieve the circuit configuration of the module10(outside door handle2) at lower cost.

(6) In the present embodiment, even for a period during which the LF antenna21is driven, since it is possible to prevent a negative voltage from being applied to the sensor IC30(power terminal34), a protection element such as a negative-voltage prevention diode may not be provide between the first module-side terminal T21and the power terminal34. Thus, it is possible to achieve the circuit configuration of the module10(outside door handle2) at lower cost.

(7) In the present embodiment, the sensor detection resistor54is provided at the passage (between the diode52and the first controller-side terminal T11) connected to the battery +B of the driving ECU50, and thus, it is possible to obtain the detection signal (the lock detection signal or the unlock detection signal) by the sensor detection circuit59by using the passage.

(8) In the present embodiment, by driving the LF antenna21and the sensor IC30by using two common wires of the first and second electric wires W1and W2, it is possible to further simplify the circuit configuration of the entire device, and it is possible to achieve low cost. Alternatively, the passage for supplying the power to the sensor IC30for a period during which the LF antenna21is driven and the passage for supplying the power for a period during which the sensor IC30is driven are used in common, and thus, it is possible to further simplify the circuit configuration of the module10(outside door handle2) and it is possible to achieve low cost.

(9) In the present embodiment, the square wave voltage VP is generated from the antenna driving voltage Vant which is generated in the constant voltage circuit53and is further stabilized, and thus, it is possible to stabilize the output, that is, the communication range of the LF antenna21, that is, a communication range. Since it is not necessary to operate the constant voltage circuit53except for the period during which the LF antenna21is driven, the occurrence of dark current is suppressed, and thus, it is possible to suppress power consumption of the battery +B.

(10) In the present embodiment, the fifth switch SW5involved in supplying the power to the LF antenna21is also used as a switch involved in supplying the power to the sensor IC30(connecting to the ground), and thus, it is possible to further simplify the circuit configuration of the driving ECU50and it is possible to achieve low cost.

Second Embodiment

Hereinafter, a vehicle door handle driving device and a vehicle communication apparatus according to a second embodiment will be described. Since the second embodiment is mainly different from the first embodiment in that an inverter realized using a so-called half bridge circuit is adopted, the detailed description of the same components will be omitted.

As shown inFIG. 4, in a driving ECU60of the present embodiment, the backflow prevention diode55is omitted, and the other end of the sensor detection resistor54is connected to the first controller-side terminal T11(first electric wire W1). The driving ECU60includes a second switch SW12and a third switch SW13connected to the other end of the constant voltage circuit53in series. The third switch SW13is grounded. The power supply51bgenerates a square wave voltage VP1having an amplitude of the antenna driving voltage Vant by alternatively switching between the ON and OFF state of the second switch SW12and the ON and OFF state of the third switch SW13(by allowing the polarities of the switches to be opposite to each another) (corresponding toFIGS. 3B and 3C). The second and third switches SW12and SW13constitute an inverter INV1realized using the so-called half bridge circuit.

In the present embodiment, the second module-side terminal T22of the module10is grounded through the electric wire W3in place of the second electric wire W2(for example, housing grounding through a vehicle body). In this case, the second connection wire that electrically connects the module10and the driving ECU60is formed by the vehicle body as the housing. The vehicle body (second connection wire) together with the driving ECU60, the module10and the first electric wire W1constitutes a vehicle communication apparatus110.

Accordingly, the square wave voltage VP1generated in the inverter INV1is output to the first controller-side terminal T11(first electric wire W1) and the second module-side terminal T22(electric wire W3) through the booster capacitor56and the resistor57.

As mentioned above, according to the present embodiment, the following effects are obtained in addition to the effects (1), (4) to (9) of the first embodiment.

(1) In the present embodiment, by adopting the inverter INV1realized using the so-called half bridge circuit, it is possible to further simplify the circuit configuration, and it is possible to achieve low cost.

(2) In the present embodiment, since it is not necessary to lay the electric wire W3over the entire area between the module10and the driving ECU60like the second electric wire W2, the electric wire W3can be shortened, and thus, it is possible to further reduce the size and weight of the entire device.

Third Embodiment

Hereinafter, a third embodiment of the vehicle door handle driving device and the vehicle communication apparatus will be described. A third embodiment is mainly different from the first embodiment in that a dedicated switch for grounding the ground terminal35of the sensor IC30is provided separately from the switches (SW2to SW5) for a period during which the LF antenna21is driven, and thus, the detailed description of the same components will be omitted.

As shown inFIG. 5, in a driving ECU65of the present embodiment, the backflow prevention diode55is omitted, and the other end of the sensor detection resistor54is connected to the first controller-side terminal T11(first electric wire W1). The second controller-side terminal T12is grounded through a sixth switch SW6interposed between the resistor58and the second controller-side terminal.

As shown inFIG. 6A, in the present embodiment, the power supply51bsets the first switch SW1to be constantly in the ON state.

As shown inFIGS. 6B to 6F, for a period during which the sensor IC30is driven (for a period during which the square wave voltage VP is not generated), the power supply51bsets the second to fifth switches SW2to SW5to be in the OFF state, and sets the sixth switch SW6to be in the ON state. Accordingly, the second controller-side terminal T12(second electric wire W2) is grounded. Accordingly, the power terminal34is connected to the battery +B through the resistor41and the first module-side terminal T21(first electric wire W1) and the ground terminal35is grounded through the second module-side terminal T22(second electric wire W2), so that the battery voltage VB of the battery +B is supplied to the sensor IC30through the first and second electric wires W1and W2.

Meanwhile, for a period during which the LF antenna21is driven and oscillates (for a period during which the square wave voltage VP is generated), the power supply51balternately switches the ON and OFF states of the second and fifth switches SW2and SW5and the ON and OFF states of the third and fourth switches SW3and SW4at the resonance frequency f1. Accordingly, the power supply51bgenerates the square wave voltage VP having the resonance frequency f1having the amplitude double that of the antenna driving voltage Vant. In this case, the power supply51bsets the sixth switch SW6to be in the OFF state. Accordingly, the LF antenna21is driven by the voltage obtained by raising the DC component of the square wave voltage VP by the battery +B. The sensor IC30is driven by the voltage obtained by raising the DC component of the square wave voltage VP by the battery +B and smoothing the voltage whose DC component is raised in the capacitor42.

For a period during which the LF antenna21is driven but does not oscillate, the power supply51bsets the second to fifth switches SW2to SW5to be in the OFF state, and sets the sixth switch SW6to be in the ON state. Accordingly, the power terminal34is connected to the battery +B through the resistor41and the first module-side terminal T21(first electric wire W1), and the ground terminal35is grounded through the second module-side terminal T22(second electric wire W2) and the sixth switch SW6. Therefore, the battery voltage VB of the battery +B is supplied to the sensor IC30through the first and second electric wires W1and W2.

Here, the sixth switch SW6that grounds the ground terminal35of the sensor IC30and the second to fifth switches SW2to SW5for a period during which the LF antenna21are separated, and thus, it is possible to achieve the configuration of the driving ECU65by combinations of cheap general-purpose ICs.

That is, as shown inFIGS. 7A to 7F, for a period during which the LF antenna21is driven and oscillates, a period during which the sensor is driven and a period during which the antenna is driven may be lapped as long as the sixth switch SW6becomes in the OFF state. That is, the sensor driving period and the antenna driving period may not be accurately distinguished.

For example, in a period T1, after the LF antenna21starts to be driven (after the LF antenna starts to oscillate) by the second to fifth switches SW2to SW5, the sixth switch SW6is maintained in the ON state, and the power is continuously supplied to the sensor IC30. In a period T2, after the LF antenna21is switched from the non-oscillation state to the oscillation state (after the LF antenna starts to oscillate) by the second to fifth switches SW2to SW5, the sixth switch SW6is maintained in the ON state, and the power is continuously supplied to the sensor IC30. However, for a period during which the LF antenna21oscillates, since there is a period during which the sixth switch SW6is in the OFF state, the LF antenna21can oscillate.

As described above, since the sensor driving period and the antenna driving period may not be accurately distinguished, the driving ECU65obtained by combining the general-purpose ICs may be used, and it is possible to realize the driving ECU65at lower cost.

As stated above, according to the present embodiment, the following effects are obtained in addition to the effects (1), (4) to (9) of the first embodiment.

(1) In the present embodiment, the sixth switch SW6that grounds the ground terminal35of the sensor IC30and the second to fifth switches SW2to SW5for a period during which the LF antenna21is driven are separated, and thus, it is possible to achieve the driving ECU65by the combinations of the cheap general-purpose ICs.

The above-described embodiments may be changed as follows.In the first embodiment, for a period during which the LF antenna21does not oscillate, the fifth switch SW5may be in the OFF state.In the third embodiment, for a period during which the LF antenna21does not oscillate, the sixth switch SW6may be in the OFF state.In the first embodiment, the backflow prevention diode55may be omitted.In the second and third embodiments, the backflow prevention diode55may be added as in the first embodiment.In the respective embodiments, the resistor43may be replaced with a capacitor or an inductance as long as an element (passive element) that causes impedance is used.In the respective embodiments, the constant voltage circuit53may be omitted, and the square wave voltage may be generated from the battery voltage VB of the battery +B.In the respective embodiments, an inverter that generates, for example, a sinusoid AC voltage may be adopted.In the respective embodiments, the first switch SW1which is basically and constantly in the ON state may be omitted, and the cathode of the diode52and the sensor detection resistor54may be directly connected.In the respective embodiments, in the configuration in which a plurality of vehicle doors is provided, for example, the first switch SW1may be in the OFF state such that the power is blocked from being supplied to a part of the outside door handles2(sensor ICs30) mounted on the plurality of vehicle doors depending on the remaining power of the battery +B. For example, in a case where the vehicle is left in a parking state for a long period, that is, for a period during which there is a few remaining power of the battery +B, the first switch SW1may be in the OFF state such that the power is blocked from being supplied to the outside door handles2(sensor ICs30) mounted on all the vehicle doors except for a vehicle door on a driver's seat. That is, “the first connection wire being constantly connected to the first positive DC power supply” means the connection in a normal vehicle use state, and does not exclude the disconnection in an abnormal vehicle use state.In the respective embodiments, the frequency (that is, resonance frequency f1) and the duty ratio of the square wave voltage for a period during which the LF antenna21oscillates may be arbitrary.In the respective embodiments, the lock detection signal or the unlock detection signal (detection signal) may be continuously output for a predetermined period (for example, a period during which approach or touch of the person is detected).In the respective embodiments, the lock detection signal and the unlock detection signal may be identified due to different voltage levels from each other.In the respective embodiments, the lock detection signal or the unlock detection signal (detection signal) may adopt an arbitrary output system such as code, voltage, or current.In the respective embodiments, for example, the antenna driving detection unit30bof the sensor IC30may detect the driving of the LF antenna21by detecting the voltage fluctuation of the power terminal34.In the respective embodiments, for example, the antenna driving detection unit30bof the sensor IC30may detect the driving of the LF antenna21by monitoring the voltage fluctuation of the power terminal34. Alternatively, the driving of the LF antenna21may be detected by providing a transformer coupling coil near the antenna coil12and monitoring the AC voltage induced in these coils by the antenna driving detection unit30bof the sensor IC30.In the respective embodiments, for a period during which the power supply51bof the driving ECU50(controller51) drives the LF antenna21, the lock and unlock controller51amay not input the lock detection signal or the unlock detection signal.In the respective embodiments, the arrangement of the lock detection area3and the unlock detection area4in the outside door handle2and the arrangement and shape of the lock sensor electrode5and the unlock sensor electrode6corresponding thereto may be appropriately changed.In the respective embodiments, any one function of the function of detecting that the hand of the person approaches or touches the lock detection area3by the lock and unlock detection unit30aand the function of detecting that the hand of the person approaches or touches the unlock detection area4may be omitted.In the respective embodiments, as various switches (SW1to SW6, SW12and SW13), a bipolar transistor, MOSFET, and a mechanical switch may be adopted.In the respective embodiments, the sensor IC30may detect approach or touch of the person using one or combinations of contact sensors or proximity sensors such as an electrostatic sensor, a shock sensor, a pyroelectric sensor, a pressure sensor, an infrared sensor, and RFID.In the respective embodiments, the sensor IC30may be manufactured using a microcomputer and an analog element such as a regulator or a transistor.In the respective embodiments, the radio signal output from the LF antenna21may be modulated by, for example, an FM modulation scheme in addition to an AM modulation scheme.In the respective embodiments, the module10may be provided within a vehicle door, a doorknob, a pillar, a side mirror, or a vehicle compartment.The embodiments disclosed herein may be applied to a so-called tire-pressure monitoring system (TPMS) that detects an air pressure or temperature of a tire through wireless communication with a sensor provided within a tire or a wheel of the vehicle.

A vehicle door handle driving device according to an aspect of this disclosure is electrically connected to an antenna and a DC driving detection member capable of detecting approach or touch of a person, which are mounted on a door handle and are connected in parallel, through a first connection wire and a second connection wire. The first connection wire is constantly connected to a first positive DC power supply, and the second connection wire is connected to a ground for a period during which the antenna is not driven. The vehicle door handle driving device includes: a booster capacitor whose one terminal is connected to the first DC power supply; and an inverter that is connected to the other terminal of the booster capacitor, is connected to a second positive DC power supply and the ground, generates an AC voltage having a resonance frequency of the antenna, and outputs the generated AC voltage to the first connection wire and the second connection wire through the booster capacitor.

According to this configuration, the first connection wire is constantly connected to the first DC power supply. Accordingly, for example, for a period during which the inverter is not driven (that is, for a period during which the antenna is not driven), a DC voltage of the first DC power supply is supplied to the detection member through the first and second connection wires by connecting the second connection wire to the ground. Meanwhile, for a period during which the inverter is driven (that is, for a period during which the antenna is driven), an AC voltage having a resonance frequency of the antenna is output to the first connection wire and the second connection wire through the booster capacitor. Accordingly, a voltage obtained by raising a DC component of the AC voltage having the resonance frequency of the antenna by a DC voltage of the first DC power supply is supplied to the detection member through the first and second connection wires. As stated above, the power is supplied to the detection member irrespective of whether or not the antenna is driven. In this case, the power can be supplied to the detection member without using the resonance voltage especially for a period during which the antenna is driven, and thus, the resonance voltage can be set without being restricted to a rated voltage of the detection member. Thus, it is possible to further reduce the size of the antenna as the Q factor of the antenna increases.

In the vehicle door handle driving device according to the aspect of this disclosure, it is preferable that the one terminal of the booster capacitor is connected to the first DC power supply through a cathode of a diode whose anode is connected to the first DC power supply.

According to this configuration, for a period during which the inverter is driven (that is, for a period during which the antenna is driven), even through the AC voltage having the resonance frequency of the antenna becomes the voltage obtained by raising the DC component by the DC voltage of the first DC power supply, the one terminal of the booster capacitor can suppress the backflow of the current toward the first DC power supply by the diode.

In the vehicle door handle driving device according to the aspect of this disclosure, it is preferable that a period during which the antenna is driven is divided into an oscillation period during which the AC voltage is generated and a non-oscillation period during which the AC voltage is not generated, and the second connection wire is connected to the ground during the non-oscillation period of the antenna.

According to this configuration, even for a period during which the antenna is driven but does not oscillate, the DC voltage of the first DC power supply can be supplied to the detection member through the first and second connection wires by connecting the second connection wire to the ground.

A vehicle communication apparatus according to another aspect of this disclosure includes: a first connection wire and a second connection wire; an antenna; a detection member that includes a power terminal and a ground terminal which are respectively connected to the first connection wire and the second connection wire, a detection output terminal which is connected to the first connection wire to output a negative detection signal indicating whether or not approach or touch of a person is detected, an antenna driving detection terminal which is connected to the first connection wire, and an antenna driving detection unit which detects a driving state of the antenna based on a voltage input to the antenna driving detection terminal; a DC cut capacitor whose both terminals are respectively connected to the detection output terminal and the antenna driving detection terminal; a passive element whose both terminals are respectively connected to the detection output terminal and the ground terminal; and the vehicle door handle driving device that further includes a lock and unlock controller which issues a lock or unlock command of a vehicle door based on the detection signal.

According to this configuration, the antenna driving detection terminal is connected to the first connection wire (power terminal) through the DC cut capacitor, and is connected to the second connection wire (ground terminal) through the passive element. Accordingly, for example, for a period during which the inverter is not driven (that is, for a period during which the antenna is not driven), the voltage supplied to the antenna driving detection terminal becomes zero. Therefore, if the detection signal is output in this state, the detection signal is output to the first connection wire in a state in which the detection signal is blocked from flowing to the ground by the DC cut capacitor. The lock and unlock controller of the vehicle door handle driving device can appropriately issue the lock or unlock command of the vehicle door based on the detection signal. Meanwhile, for a period during which the inverter is driven (that is, for a period during which the antenna is driven), the AC voltage having the resonance frequency of the antenna is output to the first connection wire and the second connection wire through the booster capacitor. Accordingly, the AC current flows to the DC cut capacitor and the passive element, and thus, as much of the voltage as the voltage drop in the passive element is supplied to the antenna driving detection terminal. Thus, the antenna driving detection unit can appropriately detect the driving state of the antenna. In this case, the driving state of the antenna can be detected without using the resonance voltage especially for a period during which the antenna is driven, and thus, the resonance voltage can be set without being restricted to the rated voltage of the antenna driving detection unit (detection member). Thus, it is possible to further reduce the size of the antenna as the Q factor of the antenna increases.

According to the aspects of this disclosure, an effect of further reducing the size of the antenna is exhibited.