JP2002269609A - Power source device for on-vehicle instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an increase of the number of connection wires, to make a consumption of a battery as less as possible and to turn off a power source after a finishing processing of an on-vehicle instrument is completed. SOLUTION: A power source device 1 for an on-vehicle instrument is provided with a voltage conversion means 11 for receiving a voltage from the battery of a vehicle 2, converting it to a predetermined voltage and outputting a power source of the predetermined voltage to the on-vehicle instrument 6; and an output current detection means 13 for detecting that a current outputted to the on-vehicle instrument 6 becomes smaller than a set value. The power source device 1 is constituted such that the voltage conversion means 11 is turned off when it is detected that the current outputted to the on-vehicle instrument 6 becomes smaller than the set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a vehicle-mounted device used when a vehicle-mounted device such as an ETC vehicle-mounted device is mounted on a vehicle.

[0002]

2. Description of the Related Art When an on-board ETC device is mounted on a vehicle,
The power supply voltage required by the on-board ETC device and the voltage of the battery mounted on the vehicle may be different. In such a case, it is necessary to prepare a power supply device for converting the voltage of the battery into the power supply voltage for the vehicle-mounted ETC.

[0003]

The above-mentioned power supply device may be provided with a regulator for converting the voltage of the battery into the power supply voltage for the vehicle-mounted ETC device. However, if the power supply device is constituted only by the regulator, the regulator is always turned on. However, there is a problem that the battery is consumed. On the other hand, when the accessory signal which is an ON signal (vehicle ON signal) output from the vehicle is on, for example, the regulator is turned on, and when the accessory signal is off, the regulator is turned off. In addition, it is possible to prevent battery consumption.

On the other hand, the on-board ETC device receives an accessory signal from the vehicle, turns on the accessory signal when the accessory signal is on, and turns off the accessory signal when the accessory signal turns off after completing a predetermined end process. It is configured.
Therefore, if the regulator of the power supply device is turned off immediately after the accessory signal is turned off as in the above-described configuration, there is a problem that the termination processing of the on-board ETC device cannot be executed normally.

As a configuration for solving this problem, ET
A configuration in which the power supply holding signal is transmitted from the vehicle-mounted device to the power supply device can be easily considered. In this configuration, ETC
When the vehicle-mounted device has completed the termination process, the vehicle-mounted device is configured not to transmit the power holding signal from the vehicle-mounted ETC to the power device, and the power device is configured to turn off the regulator when the power holding signal is no longer transmitted. I do. Thus, the power supply device can turn off the regulator after the termination processing of the on-board ETC device is completed.

However, in the case of the configuration for transmitting the power holding signal, there is a problem that the number of connecting lines connecting the on-board ETC unit and the power supply unit increases by one.

On the other hand, as a measure to prevent the number of connection lines from increasing, a configuration in which the regulator is turned off after a predetermined set time has elapsed since the accessory signal is turned off in the power supply device is conceivable. In this case, if the set time is set to a time sufficiently longer than the time required to complete the termination processing of the on-board ETC, the regulator can be turned off after the termination processing of the on-board ETC is completed. .

However, in the case of the configuration in which the elapse of the set time is set, if a long time is set as the set time, after the end processing of the on-board ETC device is completed, the time for keeping the regulator on is long, and waste is increased. . On the other hand, if the setting time is made as short as possible, if the time required to complete the end processing becomes longer due to a change in the specifications of the on-board ETC device, the regulator is turned off before the end processing is completed. Such a situation may occur.

Therefore, an object of the present invention is to prevent an increase in the number of connection lines, to minimize the consumption of a battery, and to switch off the power supply after the completion processing of the on-vehicle equipment is surely completed. An object of the present invention is to provide a power supply device for a vehicle-mounted device which can be turned off.

[0010]

According to the first aspect of the present invention, when the output current detecting means detects that the current output to the on-vehicle equipment has become smaller than the set value, the voltage converting means is activated. Because it is configured to be turned off, it is possible to prevent the number of connection lines from increasing and to minimize the consumption of the battery, and to turn off the power after the termination processing of the in-vehicle device is completely completed. Can be. In the case of this configuration, a configuration applied to, for example, an on-board ETC device as the on-vehicle device is preferable.

According to the third aspect of the invention, the output current detecting means does not perform the detecting operation when the ON signal detecting means detects the vehicle ON signal, and the ON signal detecting means does not detect the vehicle ON signal. It was configured to perform the detection operation at the time. According to this configuration, when the vehicle-on signal is detected, the detection operation is not performed. Therefore, even if the output current to the on-vehicle device may decrease for some reason during the detection of the vehicle-on signal, The situation where the voltage conversion means is turned off is eliminated.

According to the fourth aspect of the present invention, the forcible off means for forcibly turning off the voltage converting means after the set time has elapsed from when the on signal detecting means no longer detects the vehicle on signal is provided. Even if the output current to the in-vehicle device does not decrease for some reason, the voltage conversion means can be reliably turned off.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an automobile (for example, a truck) will be described below with reference to the drawings. First, as shown in the block diagram of FIG.
The power supply device 1 for an in-vehicle device according to the present embodiment includes three terminals 3, 4, 5 connected to the vehicle 2 and an in-vehicle device such as E
It is provided with three terminals 7, 8, 9 connected to the on-board TC unit 6.

[0014] The three terminals 3 connected to the vehicle 2 side,
Of the terminals 4 and 5, the terminal 3 is a power input terminal 3 to which a positive electrode of a battery mounted on the vehicle 2 is connected. In the case of the present embodiment, the vehicle 2 is, for example, a truck, and the battery is a 24 V DC power supply battery. Terminal 4 is the vehicle 2
An ON signal input terminal 4 for inputting, for example, an accessory signal, which is a vehicle ON signal output from the controller. The terminal 5 is a ground terminal 5 connected to the ground (GND) of the vehicle 2.
To which the negative electrode of the battery is connected.

Of the three terminals 7, 8, 9 connected to the on-board ETC device 6, the terminal 7 is, for example, a power output terminal 7 of a 12V DC power supply, which is a power input terminal of the on-board ETC device 6. Connected to. The terminal 8 is an ON signal output terminal 8 that transmits and outputs an ON signal from the vehicle 2, and is connected to an ON signal input terminal of the vehicle-mounted ETC device 6. The terminal 9 is a ground terminal 9 to which the ground terminal of the on-board ETC device 6 is connected.

The power supply 1 includes a main switch (ON means) 10 and a regulator (voltage conversion means) 1.
1, an ON signal detection circuit (ON signal detection means) 12,
An output current detection circuit (output current detection means) 13 and an off timer circuit (forced off means) 14 are provided. The main switch 10 is composed of, for example, a transistor, and is provided between the power input terminal 3 and the input terminal of the regulator 11. The regulator 11
It has a function of inputting a 24V DC voltage, converting it to a 12V DC voltage, and outputting it.

The output terminal of the regulator 11 is connected to the power output terminal 7 via the output current detection circuit 13. The output current detection circuit 13 includes a comparator 15, a current detection resistor 16, and voltage dividing resistors 17, 18, and 19. The comparator 15 outputs, for example, a high-level output signal Sa when the output current Ia is larger than a predetermined set value, and outputs a low-level output signal Sa when the output current Ia becomes smaller than the set value. It is configured. In this case, the magnitude of the set value is set to a current value, for example, about １ ／ of the magnitude (normal current value) of the output current Ia flowing when the on-board ETC device 6 operates normally. In addition, the magnitude of the above set value is
It may be changed as appropriate.

The output signal Sa from the comparator 15 is supplied to the regulator 11. When the regulator 11 receives the low-level output signal Sa from the comparator 15, the regulator 11 is turned off and stops outputting the voltage. In this configuration, the regulator 1
Reference numeral 1 denotes off means.

The on-signal detection circuit 12 has a function of detecting whether the vehicle-on signal Sb output from the vehicle 2 is on or off, and that the vehicle-on signal Sb is on. Is detected, an ON detection signal Sc is output. The ON signal detection circuit 1
2 is configured to output an off detection signal Sc when detecting that the vehicle on signal Sb is off. Further, the ON signal detection circuit 12 outputs the vehicle ON signal Sb
(In the case of the present embodiment, the circuit is configured to operate with power of, for example, a voltage signal of 24 V), and operates even when the main switch 10 is off.

The ON signal detection circuit 12 sends the detection signal Sc to the main switch 10 and the comparator 1
5 and a switch 20 described later. In this case, the main switch 10 is configured to be turned on (closed) when receiving the on detection signal Sc. Upon receiving the ON detection signal Sc, the comparator 15 invalidates the above-described comparison processing and continues to output the high-level output signal Sa. And comparator 1
5 is configured to, upon receiving the OFF detection signal Sc, validate the above-described comparison processing and output an ON or OFF output signal Sa according to the comparison result.

Further, the switch 20 is formed of, for example, a transistor, and is configured to turn on when receiving the ON detection signal Sc, and to turn OFF when receiving the OFF detection signal Sc.

Further, the off-timer circuit 14 includes, for example, a CR
And the like, and a switch 22 composed of, for example, a transistor. In this case, the switch 20 is provided between the input terminal of the time constant circuit 21 and the output terminal of the regulator 11. The switch 22 is provided between the output terminal of the regulator 11 and the control terminal of the main switch 10.

In the case of the above configuration, when the ON signal detection circuit 12 outputs the ON detection signal Sc, the switch 20 is turned on, and the output voltage of the regulator 11 is applied to the time constant circuit 21. Is immediately (rapidly) charged, giving an ON signal to the switch 22 and turning the switch 22 ON. When the switch 22 is turned on, an ON self-holding signal Sd is supplied to the main switch 10, and the ON state of the main switch 10 is self-held. In this self-holding state, the ON signal detection circuit 12 outputs the vehicle ON signal Sb of OFF to the main switch 1.
Even when the value is given to 0, the main switch 10 keeps on. That is, the switch 22 and the conduction path of the switch 22 constitute a self-holding circuit (self-holding means).

In this case, the main switch 10 is turned on when the logical sum signal of the detection signal Sc from the on signal detection circuit 12 and the self-holding signal Sd from the switch 22 is on, and the signal of the logical sum is off. It is configured to be turned off when. Therefore, the condition for turning off the main switch 10 is when the off detection signal Sc and the off self-holding signal Sd are received.

The self-holding signal Sd is turned off when the regulator 11 is turned off or when the switch 22 of the off timer circuit 14 is turned off.
The condition that the switch 22 of the off-timer circuit 14 is turned off is such that a set time, for example, about 40 seconds elapses after the switch 20 is turned off and the time constant circuit 21 starts measuring time, and the off signal is switched. 22. At this time, the switch 22 is turned off.

The connection point between the switch 20 and the input terminal of the time constant circuit 21 is connected to the ON signal output terminal 8. As a result, the ON signal detection circuit 12 outputs the ON vehicle ON signal Sb, and when the switch 20 is turned ON, the ON signal transmission signal Se is supplied to the ON signal output terminal 8. That is, the vehicle-on signal Sb output from the vehicle 2 is transmitted to the on-board ETC
Will be transmitted to Note that the off vehicle on signal Sb is output from the on signal detection circuit 12 and the switch 20 is turned off.
Is turned off, an off on signal transmission signal Se is supplied to the on signal output terminal 8.

In the case of the above configuration, the vehicle-on signal Sb output from the vehicle 2 is a voltage signal of +24 V when on, and the on-signal transmission signal Se in the power supply 1 is a voltage signal of +12 V when on. is there. That is, the configurations of the ON signal detection circuit 12 and the switch 20 of the power supply device 1 have a function of converting the voltage level of the vehicle ON signal Sb and transmitting the voltage level to the vehicle-mounted ETC device 6. In the case of this configuration, the configuration of the ON signal detection circuit 12, the switch 20, and the like constitute ON signal transmission means.

Next, the operation of the above configuration will be described with reference to the time charts of FIGS. Note that the time chart of FIG. 2 shows control when the regulator 11 is turned off based on detection of the output current of the power supply device 1 (hereinafter, referred to as output current detection control). FIG.
The time chart of FIG. 4 shows a control (hereinafter, referred to as a control) when the off timer circuit 14 operates to forcibly turn off the regulator 11.
Off timer control).

First, the output current detection control will be described with reference to FIG. As shown in FIG. 2, assuming that the vehicle-on signal Sb output from the vehicle 2 changes from off to on at time 1, the on-signal detection circuit 12 outputs the on detection signal Sc at this time. Become.
Thereby, while the main switch 10 is turned on,
The switch 20 is turned on, and the comparator 15 invalidates the comparison processing and outputs the output signal Sa which is always at the high level.
Is output to the regulator 11.

As a result, at time t1, the regulator 11
Is turned on, and a DC voltage (power supply) of 12 V is output from the power supply output terminal 7. At the same time, the switch 22 of the off timer circuit 14 is turned on, and the self-hold signal Sd of on is given to the main switch 10,
The ON state of the main switch 10 is self-held. Also, since the switch 20 is turned on,
The ON (12 V) ON signal transmission signal Se is output from the ON signal output terminal 8.

As a result, the on-board ETC device 6 can use the 12 V DC power supply from the power supply device 1 and transmit the ON signal transmission signal Se synchronized with the vehicle ON signal Sb output from the vehicle 2. To receive it. As a result, the vehicle-mounted ETC device 6 is turned on and operates.

Thereafter, it is assumed that the vehicle-on signal Sb output from the vehicle 2 has been turned off at time t2. Then, at this point, the ON signal detection circuit 12 outputs the OFF detection signal Sc, so that the switch 20 is turned OFF and the comparator 15 performs the comparison processing. In this case, even if the OFF detection signal Sc is given to the main switch 10, the main switch 10 is kept on by the ON self-holding signal Sd. A DC voltage of 7 to 12 V is continuously output.

At time t2, since the switch 20 is turned off, the on signal transmission signal S is turned off.
e is output from the ON signal output terminal 8 to the on-board ETC device 6. For this reason, the vehicle-mounted ETC device 6 receives the on signal transmission signal Se for turning off, and starts executing a predetermined end process. At this time, when the on-board ETC device 6 is executing the termination process, the magnitude of the output current (current consumption of the on-board ETC device 6) output from the regulator 11 (that is, the power output terminal 7) is larger than the set value. Therefore, the comparator 15 outputs a high-level output signal Sa to the regulator 11.

At time t3, the on-board ETC device 6
Is completed, the magnitude of the output current output from the regulator 11 becomes smaller than the set value. still,
The time required for the end processing, that is, the time ta shown in FIG.
Is, for example, about 12 seconds. Then, at the time t3, the comparator 15 outputs the low-level output signal S.
Since a is output to the regulator 11, the regulator 11 is turned off in response to this. As a result, the power output terminal 7 becomes Ov. At the same time, the OFF self-hold signal S
Since d is given to the main switch 10, the main switch 10 is turned off, the regulator 11 is turned off, and the power supply device 1 is turned off.

Next, the off-timer control will be described with reference to FIG. As shown in FIG. 3, after the vehicle-on signal Sb output from the vehicle 2 changes from off to on at time 1, the control until the vehicle-on signal Sb changes to off at time t2 is as described above. The description is omitted because it is the same as the output current detection control described above.

Now, after the time t2, the on-board ETC device 6
Is executed, it is assumed that the magnitude of the current output from the regulator 11 (that is, the power output terminal 7) does not become smaller than the set value due to some reason, for example, a failure or the like. In this case, since the comparator 15 continues to output the high-level output signal Sa to the regulator 11, the regulator 11 keeps on.

In this state, at time t4 when a set time tb (for example, about 40 seconds) has elapsed from time t2, in the off timer circuit 14, the time constant circuit 21 finishes timing and switches off the signal to the switch 22. And the switch 22 is turned off. As a result, the OFF self-holding signal Sd is supplied to the main switch 10, and the main switch 10 is turned off at time t4. As a result, the regulator 11 is forcibly turned off,
The power output terminal 7 becomes Ov, and the power supply device 1 is turned off.

According to the present embodiment having such a configuration, when the output current detection circuit 13 detects that the output current output to the ETC on-vehicle device 6 has become smaller than the set value, the regulator 11 is activated. Since it is configured to be turned off, it is possible to prevent an increase in the number of connection lines (three in the present embodiment) connecting the power supply device 1 and the vehicle-mounted ETC device 6 and to reduce the consumption of a battery mounted on the vehicle 2. Can be reduced as much as possible. In particular, in the case of the above embodiment, 24V
It is possible to use the vehicle-mounted ETC device 6 manufactured for a vehicle (e.g., a passenger car) equipped with a 12V battery as it is, even though the vehicle (e.g., a truck) 2 is equipped with a battery. This eliminates the need to separately manufacture the ETC vehicle-mounted device 6 having a different power supply voltage.

In the above embodiment, the comparator 15 of the output current detection circuit 13 is connected to the ON signal detection circuit 1.
No detection operation is performed when the vehicle ON signal Sb 2 is detected, and the detection is performed when the ON signal detection circuit 12 stops detecting the vehicle ON signal Sb (when the OFF vehicle ON signal Sb is detected). Configured to work. According to this configuration, when the on-vehicle on signal Sb is detected, the detection operation is not performed.
During the detection of b, even if the output current to the ETC on-vehicle device 6 becomes smaller for some reason and becomes smaller than the set value, it is possible to prevent a situation in which the regulator 11 is turned off. .

Further, in the above embodiment, after the set time tb elapses from when the ON signal detection circuit 12 stops detecting the ON vehicle ON signal Sb (that is, when the OFF vehicle ON signal Sb is detected). And the off-timer circuit 14 for forcibly turning off the main switch 10 and, consequently, the regulator 11.
Even if the output current to the on-board TC 6 does not decrease for some reason (such as failure), the regulator 1
1 can be reliably turned off. Therefore, even when a failure or the like occurs, the consumption of the battery of the vehicle 2 can be reduced.

In the above embodiment, when it is detected that the current output to the on-board ETC device 6 has become smaller than the set value, the comparator 15 of the output current detection circuit 13 outputs the low-level signal Sa to the regulator. 11, the regulator 11 is turned off.
The present invention is not limited to this. For example, a switch composed of a transistor or the like may be provided in the current path of the self-holding circuit, and this switch may be turned off by the output signal Sa from the comparator 15 to turn off the main switch 10. Is also good.

In the above embodiment, the off-timer circuit 1
4, the off-timer circuit 14 may be stopped instead, and the output of the regulator 11 may be supplied to the main switch 10 as a self-holding signal. Further, in the above embodiment,
Although the output voltage of the regulator 11 was set to 12 V, the present invention is not limited to this.
The constant DC voltage may be used. With this configuration, the power supply circuit inside the on-board ETC device can be eliminated.

In the above embodiment, the present invention is applied to, for example, the on-board ETC device 6 as the on-vehicle device. However, the present invention is not limited to this. Can be.

[Brief description of the drawings]

FIG. 1 is an electrical configuration diagram showing one embodiment of the present invention.

FIG. 2 is a time chart of output current detection control.

FIG. 3 is a time chart of off-timer control.

[Explanation of symbols]

1 is a power supply device for on-vehicle equipment, 2 is a vehicle, 3 is a power supply input terminal, 4 is an on signal input terminal, 6 is an ETC on-vehicle device (vehicle equipment), 7 is a power supply output terminal, 8 is an on signal output terminal, 10
Is a main switch (ON means), 11 is a regulator (voltage conversion means, OFF means), 12 is an ON signal detection circuit (ON signal detection means), 13 is an output current detection circuit (output current detection means), and 14 is an OFF timer circuit (Forced off means), 15 is a comparator, 16 is a current detection resistor, 20
Indicates a switch, 21 indicates a time constant circuit, and 22 indicates a switch.

Claims (4)

[Claims] 1. A voltage conversion means for receiving a voltage output from a battery mounted on a vehicle, converting the voltage to a predetermined voltage, and outputting a power supply of the predetermined voltage to on-vehicle equipment, and a vehicle on-state output from the vehicle. ON signal detecting means for detecting a signal, ON means for turning on the voltage conversion means when the ON signal detecting means detects the vehicle ON signal, and ON signal detecting means for detecting the vehicle ON signal ON signal transmission means for outputting an ON signal to the on-vehicle device when the vehicle is on, output current detection means for detecting that the current output to the on-vehicle device has become smaller than a set value, and this output current detection means A power supply device for an in-vehicle device, comprising: an off unit that turns off the voltage conversion unit when detecting that the current has become smaller than a set value. 2. The power supply device for a vehicle-mounted device according to claim 1, wherein the vehicle-mounted device is an ETC vehicle-mounted device. 3. The output current detection means does not perform a detection operation when the ON signal detection means detects the vehicle ON signal, and when the ON signal detection means stops detecting the vehicle ON signal. The power supply device for an in-vehicle device according to claim 1, wherein the power supply device is configured to perform a detection operation. 4. After a lapse of a set time from when the on signal detecting means stops detecting the vehicle on signal,
The power supply device for a vehicle-mounted device according to any one of claims 1 to 3, further comprising forcible off means for forcibly turning off the voltage conversion means.