JPH05202657A - Transmitter for locking and unlocking lock for vehicle - Google Patents

Abstract

PURPOSE:To save the electric power for a transmitter as much as possible by changing over the strength of a control signal transmitted to the position to be controlled. CONSTITUTION:An inversion circuit 17 to invert a key code signal, and a supply means to selectively supply a key code signal S6 inverted by the inversion circuit 17 to the other end side of a resonance circuit 18 to one side of which a non-inversion key code signal S5 is supplied are provided. A control signal at being not supplied with the inverted key code signal S6, and a control signal at being supplied with the inverted key code signal S6 and amplified, are transmitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a keyless entry system for locking and unlocking a lock provided on a door or trunk of a vehicle such as an automobile at a position remote from the vehicle. Regarding the transmitter.

[0002]

2. Description of the Related Art In recent automobiles, it is possible to use an electrical or optical control signal to lock or unlock a door lock or a trunk lock at a position remote from the automobile. -Some are equipped with a less entry system. In this system, a receiver provided in the automobile and a portable transmitter independent of the automobile are used.

FIG. 3 shows an example of a transmitter circuit equipped in this type of transmitter. Microcomputer 11 shown
In particular, a specific key code for each vehicle is preprogrammed, and this program is sequentially advanced according to the clock pulse S1 sent from the oscillator 12. The microcomputer 11 is a key number
Code is replaced with a predetermined pulse width, and code replacement pulse S2
Is output.

This code replacement pulse S2 is raised by a resistor 13 to which Vcc is applied and is raised.
3 is input to the crystal oscillator 14. Crystal oscillator 14
Frequency-modulates the code replacement pulse S3 with the carrier frequency and outputs it as a key code signal S4.

This key code signal S4 has a waveform shaping circuit 1
5, the waveform is shaped and sent to the one end P of the resonance circuit 18 as a key code signal S5. The key code signal S4 is shaped by the waveform shaping circuit 16 and then inverted by the inverting circuit 17 and sent to the other end Q of the resonance circuit 18 as the key code signal S6. In addition, in FIG.
In the partial view of the key code signals S5 and S6, as can be seen from this figure, these signals S5 and S6 are level-inverted, and the non-inverted key code signal S5 and the inverted key code S5. -De signal S
It is 6.

The resonance circuit 18 to which the key code signals S5 and S6 are applied transmits a high frequency control signal according to the resonance frequency from the antenna 19. The transmitter thus constructed has a non-inverted code code signal S5 and an inverted key code signal S6 at both ends P and Q of the resonance circuit 18.
To cause the resonance circuit 18 to resonate,
A control signal having the amplitude twice that of the code signal is transmitted.

Another conventional example is a non-inversion key.
Resonating the resonance circuit 18 by giving only the code signal S5,
A transmitter configured to transmit a control signal from the antenna 19 is known.

When the receiver mounted on the vehicle receives the control signal transmitted from the transmitter, the receiver demodulates the control signal and, according to the demodulated pulse signal, the door lock or the like. Lock and unlock.

[0009]

The transmitter shown in FIG. 3 has a non-inverted key code signal S5 and an inverted key code signal S5.
Since the control signal is sent by giving the code signal S6 to the resonance circuit 18, the power-up control signal is always transmitted regardless of the distance to the vehicle. As a result, the battery power source installed in the transmitter consumes more power than necessary, resulting in a short battery life.

Further, the transmitter which sends only the non-inverted key code signal S5 to the resonance circuit and transmits the control signal, when the control is attempted at a predetermined distance or more,
Power shortages occur, making reliable locking or unlocking difficult.

In view of the above situation, a first object of the present invention is to develop a transmitter which can be powered up when controlling at a predetermined distance or more from an automobile. It is a second object of the present invention to develop a transmitter capable of automatically switching to power-up when the power supply battery of the device drops below a predetermined voltage and increasing and transmitting the weakened control signal. To do.

[0012]

In order to achieve the above-mentioned object, in the present invention, as a first invention, a key code signal modulated by a carrier wave is applied to a resonance circuit, and the resonance frequency of the resonance circuit is changed. Therefore, in a transmitter for locking and unlocking a vehicle lock that transmits a high-frequency control signal, the key is
An inverting circuit for inverting the code signal and a non-inverting key code
An inverted key code signal is provided on the other end side of the resonance circuit which has supplied the one end signal side with a supply means for selectively supplying the key code signal inverted by the inversion circuit. Control signal when not supplied and the inverted key
We propose a transmitter characterized in that a code signal is supplied to transmit a control signal whose amplitude has been expanded.

According to a second invention, in the transmitter of the first invention, a detection circuit for detecting a voltage level of a battery power source provided in the transmitter and generating a detection signal when the voltage level drops below a predetermined value, A transmitter is provided, which is provided with a supply means including a gate circuit for inputting the detection signal, opening the gate, and supplying the above-mentioned inverted key code signal to the resonance circuit. To do.

[0014]

In the transmitter according to the first aspect of the present invention, the non-inverted key code signal is immediately supplied to the resonance circuit by the operation of the trigger switch. Therefore, unless the inverted key code signal is supplied, the resonance circuit resonates with the non-inverted key code signal, and a high-frequency control signal that is not powered up is transmitted.

When an inverted key code signal is supplied,
The resonance circuit resonates with the non-inverted key code signal and the inverted key code signal, and a high-frequency control signal of twice the power is transmitted. For this reason, when controlling from a short distance, power-up is not performed, and when controlling from a long distance, power-up can be performed to perform lock control.

In the transmitter of the second aspect of the present invention, the gate circuit is closed and the supply of the inverted key code signal is cut off while the voltage level of the battery power source exceeds a predetermined value. Therefore,
An unpowered control signal is transmitted.

When the voltage level of the battery power source drops below a predetermined value, the strength of the control signal transmitted becomes weak. In this case, the gate circuit responds to the detection signal generated by the detection circuit. Is opened and supplies the inverted key code signal to the resonant circuit, so that the increased control signal is transmitted. As a result, even if the voltage level of the battery power source drops considerably, a control signal sufficient for lock control can be transmitted.

[0018]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a transmitter circuit diagram showing a first embodiment. As shown in the figure, this embodiment is characterized in that a changeover switch 20 is provided on the ground side of the resonance circuit 18. The other structure is similar to that of the conventional example shown in FIG.

In the above embodiment, the changeover switch 20 is connected to the terminal a.
And the inverted key code signal S6 is cut off. In this case, since the resonance circuit 18 resonates with the non-inverted key code signal S5, a high frequency control signal which is not powered up is transmitted from the antenna 19.

When the changeover switch 20 is turned on to the terminal b,
Inversion key code signal S6 output from the inversion circuit 17
Are supplied to the resonance circuit 18. Therefore, the resonance circuit 1
8 resonates with the non-inverted key code signal S5 and the inverted key code signal S6, and the power-up high frequency control signal is transmitted from the antenna 19.

FIG. 2 is a partial view of the transmitter circuit shown as the second embodiment. In this embodiment, the inverted key code signal S6 is supplied to the resonance circuit 18 when the voltage level of the battery power source becomes a predetermined value or less.

That is, in this embodiment, the resistor 21, the diodes 22 and 23, and the NOT circuit 24 form a voltage detection circuit for the battery power supply. This detection circuit sets one input terminal 25a of the NOR circuit 25 to a high voltage (hereinafter, referred to as H) when the voltage level exceeds a predetermined value, and when the voltage level becomes a predetermined value or less, the input terminal 25a.
Is held at a Low voltage (hereinafter referred to as L).

That is, the input terminal 24 of the NOT circuit 24.
A constant voltage generated in the diodes 22 and 23 is input to a, and this input voltage is compared with the threshold voltage of the NOT circuit 24. Although the threshold voltage drops according to the voltage drop of the battery power supply, when the power supply voltage level exceeds a predetermined value, the threshold voltage is large compared to the input voltage and the output of the NOT circuit 24 becomes the H voltage. Become.
When the power supply voltage level drops below a predetermined value, the threshold voltage becomes smaller than the input voltage, and the NOT circuit 2
The output of 4 becomes the L voltage.

Therefore, when the voltage level of the battery power source exceeds the predetermined value, the key code signal output from the waveform shaping circuit 16 is the other input terminal 2 of the NOR circuit 25.
5b, input terminal 25a is H, input terminal 25b
Becomes H and L, the output of the NOR circuit 25 is always L, and the inverted key code signal S6 is not output. As a result, the resonance circuit 1 is driven by the non-inverted key code signal S5.
8 resonates and transmits a high frequency control signal.

When the voltage level of the battery power source drops below a predetermined value, one input terminal 25a of the NOR circuit 25 is at L, and the key code signal output from the waveform shaping circuit 16 is It passes through the NOR circuit 25. That is, the key code signal output from the waveform shaping circuit 16 is NO.
The key code signal S6 which is inverted by the R circuit 25 and is inverted is supplied to the resonance circuit 18. That is, the NOR circuit 25 outputs L at L and L at the input terminals 25a and 25b, and outputs at H.
When the input terminals 25a and 25b are L and H, the output is L.

As a result, the resonance circuit 18 resonates with the non-inverted key code signal S5 and the inverted key code signal S6, and the control signal is increased. The diodes 22 and 23 provided in the detection circuit can be replaced with Zener diodes.

[0027]

As described above, the strength of the control signal to be transmitted can be switched between two levels. Therefore, the strength of the control signal can be changed according to the distance between the vehicle and the control position to lock or unlock the control signal, and the transmitter is extremely advantageous for saving transmitter power.

Further, even when the voltage level of the battery power source drops below a predetermined value, the gate circuit is opened by the detection signal of the detection circuit and the inverted key code signal is supplied to the resonance circuit. , The augmented control signal is transmitted. As a result, it becomes a transmitter capable of transmitting a control signal sufficient for locking and unlocking even when the voltage level of the battery power source drops considerably.

[Brief description of drawings]

FIG. 1 is a transmitter circuit diagram shown as a first embodiment.

FIG. 2 is a partial view of a transmitter circuit shown as a second embodiment.

FIG. 3 is a transmitter circuit diagram of a transmitter shown as a conventional example.

FIG. 4 is a partial diagram showing a non-inverted key code signal and an inverted key code signal.

[Explanation of symbols]

 11 Microcomputer 12 Oscillator 14 Crystal Oscillator 15 and 16 Waveform shaping circuit 17 Inversion circuit 18 Resonance circuit 19 Antenna 20 Changeover switch 25 NOR circuit S5 Non-inversion key code signal S6 Inversion key code signal

Claims (2)

[Claims] 1. A locking / unlocking transmitter of a vehicle lock, wherein a key code signal modulated by a carrier wave is applied to a resonance circuit, and a high frequency control signal is transmitted according to the resonance frequency of the resonance circuit. An inverting circuit for inverting the code signal, and a key code signal inverted by the inverting circuit at the other end of the resonance circuit having a non-inverted key code signal supplied to one end. A control means provided with a supply means for selectively supplying the control signal when the inverted key code signal is not supplied and the control signal for supplying the inverted key code signal to increase the amplitude. A transmitter having a structure for transmitting a signal. 2. A detection circuit for detecting a voltage level of a battery power source provided in a transmitter and generating a detection signal when the voltage level drops below a predetermined value, and a gate for inputting the detection signal.
2. A transmitter according to claim 1, further comprising: a supply circuit comprising a gate circuit for opening the gate and supplying the above-mentioned inverted key code signal to the resonance circuit.