JPH07223509A - Burglary preventing device for vehicle - Google Patents

Abstract

PURPOSE:To output alarm signals when a battery voltage rises by supplying detection signals for start of supply of battery voltage from a battery voltage detection circuit when an ignition switch is turned off and also supplying alarm indication signals to an alarm means by a microcomputer when on-signals are supplied from an invasion detection switch to it. CONSTITUTION:A variation in battery voltage of a battery 1 is monitored directly and, when the battery voltage rises while an ignition switch 2 is turned off, the output voltage of the battery 1 is inputted into a direct control microcomputer 9 by a battery voltage detecting circuit 16. When the input voltage of the control microcomputer 9 is raised to a specified voltage within a specified time limit and also an invasion detecting switch 3 interlocked with the opening operation of a door for entry into a vehicle is turned on, the microcomputer 9 prepares alarm indication signals and emits alarm by an alarm means 13. Thus alarming treatment can be made securely by simple signal treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention shuts off the power supply system of an alarm device, disables the alarm device, and once the vehicle is intruded, the power supply system is normally connected again to alarm the vehicle. The present invention relates to a vehicle burglar alarm device.

[0002]

2. Description of the Related Art The structure of a vehicle antitheft device of this type will be described with reference to FIG. In FIG. 2, 1 is an on-vehicle battery, 2 is an ignition switch, and 3 is a door switch, which is turned on when the door is opened. 4 is a hood switch, which turns on when the engine room is opened. A trunk switch 5 is turned on when the trunk room is opened. 6 is a power supply circuit, which is constantly fed from the battery 1,
A predetermined voltage is supplied to each circuit section of the first vehicle-mounted device 11 described later.

Reference numeral 7 denotes a reset circuit, which inputs a voltage output from the power supply circuit 6 to a control microcomputer 9 described later, and when the voltage becomes lower than a predetermined voltage, that is, the control microcomputer 9 is turned on. When the voltage immediately before the voltage at which driving becomes impossible is reached, a reset signal is supplied to the control microcomputer 9 described later.

An input interface circuit 8 has input terminals connected to the output side terminals of the ignition switch 2, the door switch 3, the hood switch 4 and the trunk switch 5, respectively, so that a signal output from each switch rises. , And performs waveform shaping of the falling waveform and supplies it to the control microcomputer 9 described later. Reference numeral 10 denotes an output interface circuit for supplying an output signal from a control microcomputer 9 described later, that is, an alarm instruction signal to the alarm means 13.

Reference numeral 11 denotes a volatile storage unit such as a RAM. When a reset signal is supplied from the reset circuit 7 to a control microcomputer 9 to be described later, the reset signal is stored according to an instruction from the control microcomputer 9. Reference numeral 14 denotes a power supply backup circuit, which is another in-vehicle device (second in-vehicle device) 15
Since the backup power supply circuit has a simple circuit configuration, when the output voltage of the power supply circuit 6 drops, the backup power supply circuit works to compensate for it.

Reference numeral 12 denotes a first vehicle-mounted device, which is composed of a power supply circuit 6, a reset circuit 7, an input interface circuit 8, a control microcomputer 9, an output interface circuit 10 and a storage section 11.

Next, a description will be given of the control microcomputer 9 which is constantly supplied with power from the power supply circuit 6 together with a description of the operation of the entire apparatus.

That is, the control microcomputer 9
Since the power is supplied from the power supply circuit 6 even when the ignition switch 2 is turned off, it is always in the operating state during this period. Therefore, when any one of the door switch 3, the hood switch 4, and the trunk switch 5 is turned on, for example, when the door switch 3 is turned on by opening the door (door) by trying to break into the vehicle due to an abnormal operation,
The alarm means 12 is operated via the output interface circuit 10 to start preparation for generating an alarm instruction signal for issuing an alarm.

Next, when the output voltage of the power supply circuit 6 drops below a predetermined voltage due to the removal of the battery 1 in an attempt to enter the vehicle, the control microcomputer 9 operates to protect the data. Immediately before being reset by the reset circuit 7, this phenomenon is stored in the storage unit 11 as if the battery 1 was removed. Furthermore, when the control microcomputer 9 is supplied with power again from the power supply circuit 6, the stored contents of the storage unit 11 are read, and the voltage supplied from the power supply circuit 6 to the read contents is lowered to a predetermined voltage or less. In the case described, the alarm means 13 is operated through the output interface circuit 10 and the alarm instruction signal for issuing an alarm is output.

That is, in order to prevent the operation of the theft alarm device, the battery 1 is temporarily removed, and after the battery 1 has entered the vehicle, the battery 1 is connected again to drive the vehicle, and the alarm device operates. It will be.

[0011]

However, in such vehicle theft prevention, the storage unit 11 uses a RAM having a relatively large variation in the holding voltage for holding the stored contents. In a short time, that is, when the battery 1 is removed, the battery 1 immediately enters the vehicle, and the battery 1 is immediately connected, the storage unit 1
1 does not remember that battery 1 was removed,
There is a problem that the anti-theft device does not work.

Further, in a fully equipped luxury vehicle, the power backup circuit 14 has a large capacity, so that the power backup circuit 14 remains even after the battery 1 is removed.
Since the current leaks from the power supply circuit 6 and is replenished to the power supply circuit 6, the output voltage of the power supply circuit 6 decreases at a low rate.
It took a relatively long time for the reset signal to be output from the reset circuit 7. Therefore, there is a problem in that the storage unit 11 having a low holding voltage gives sufficient time to steal the vehicle.

The present invention has been made in view of such a problem, and directly monitors the battery voltage without using any storage unit including RAM, and when the ignition switch is turned off, An object of the present invention is to improve the reliability of the device by outputting an alarm signal when the battery voltage rises.

[0014]

A vehicle antitheft device according to the present invention includes a power supply circuit directly connected to a battery,
A battery voltage detection circuit that is directly connected to the battery and monitors the battery voltage, an ignition switch, an intrusion detection switch that is turned on in association with an opening operation of a door for entering the vehicle, and constant power supply from the power supply circuit When the ignition switch is turned off, the battery voltage detection circuit supplies a detection signal indicating the start of supply of the battery voltage of the battery, and when the intrusion detection switch supplies an on signal, an alarm instruction is issued. And a microcomputer that supplies a signal to the alarm means, and the alarm means issues an alarm in response to the alarm instruction signal.

[0015]

The antitheft device for a vehicle according to the present invention directly monitors a change in the battery voltage, and if the battery voltage rises while the ignition switch is turned off, the vehicle is alarmed as being in a theft state. Output a signal.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below with reference to FIG. In FIG. 1, the same components as those described with reference to FIG. 2 or equivalent components are designated by the same reference numerals, and the description thereof will be omitted. Only different components will be described below.

That is, in FIG. 1, 16 is a battery voltage detection circuit, which directly inputs the output voltage of the battery 1,
When the input voltage rises to a predetermined voltage value within a predetermined time, it is assumed that the battery 1 is reconnected, and the control microcomputer 9 is caused to generate an alarm instruction signal for operating the alarm means 13. To output to the control microcomputer 9. It should be noted that in FIG. 1, the storage unit 11 is omitted from FIG.

[0018]

As described above, according to the present invention, the effect that the accuracy can be improved without incurring much cost by adopting the configuration for performing the simple signal processing is exhibited.

[Brief description of drawings]

FIG. 1 is a circuit block explanatory diagram showing an embodiment of the present invention.

FIG. 2 is a circuit block explanatory diagram for explaining a conventional example.

[Explanation of symbols]

 1 Battery 2 Ignition Switch 3 Door Switch 4 Hood Switch 5 Trunk Switch 6 Power Supply Circuit 7 Reset Circuit 8, 10 Interface 9 Control Microcomputer 11 Storage Unit 14 Power Supply Backup Circuit 16 Battery Voltage Detection Circuit

Claims (1)

[Claims] 1. A power supply circuit (6) directly connected to a battery (1) and a battery voltage detection circuit (15) directly connected to the battery (1) to monitor the battery voltage.
An ignition switch (2), an intrusion detection switch (3, 4, 5) which is turned on in conjunction with an opening operation of a door for entering the vehicle, and the power supply circuit (6) to constantly supply power to the ignition switch. When the switch (2) is off, a detection signal indicating the start of supply of the battery voltage of the battery (1) is supplied from the battery voltage detection circuit (15), and the intrusion detection switch (3, 4,
5) a microcomputer (9) for supplying an alarm instruction signal to the alarm means (13) when an ON signal is supplied from the alarm signal (5), the alarm means (13) issuing an alarm upon receiving the alarm instruction signal. Anti-theft device for vehicles.