JP2002144986A - Power supply control device for use in navigation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take a countermeasure to runaway of the software of a power supply monitoring microcomputer and allow a display to be inserted into a casing when an ignition switch is turned from the ACC to OFF position. SOLUTION: The invention includes an insertion/removal drive circuit 15 to emit a Hi level signal for a certain period of time when the ignition switch is switched from the ACC to OFF position. Thereby a Hi level signal is emitted from an OR circuit 16 provided in a forced cutoff circuit 14 for a certain period of time even if the ACC signal is at the Low level, and it is possible to put on a power switch 12 to establish power supplying from a constant voltage source 11 to an internal power supply 10. After the lapse of the specified period, a Low level signal is emitted from the OR circuit 16, and the power switch 12 is turned off forcedly irrespective of the power supply control signal emitted by the power supply monitoring microcomputer 13. This allows effective countermeasure to a runaway of the software of microcomputer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power supply control device for a so-called in-dash type navigation device.

[0002]

2. Description of the Related Art Conventionally, there is a case where a navigation device is provided with a power supply monitoring microcomputer, and the power supply is controlled by the power supply monitoring microcomputer. In such a case, as a countermeasure against software runaway of the power supply monitoring microcomputer (battery rising countermeasure), as shown in FIG. 4A, the ignition switch provided in the vehicle is switched from the ACC (accessory) position to the OFF position. A circuit (hereinafter, referred to as an ACC forcible shutoff circuit) 101 for detecting and forcibly interrupting the voltage supply to the internal power supply 100 provided in the navigation device is added between the power supply monitoring microcomputer 102 and the power switch 103. That is, the supply of voltage to the navigation device even after the ignition switch is switched from the ACC position to the OFF position and the supply of voltage is cut off is considered to be a soft runaway of the power supply monitoring microcomputer 102. For this reason, the ACC signal whose output level changes depending on whether the switch is in the ACC position (or the ignition switch is in the ON position) or has been switched to the OFF position is input to the AND circuit 101a provided in the ACC forced cutoff circuit 101. The voltage supply is forcibly cut off based on the ACC signal.

[0003]

There is a so-called in-dash type navigation device configured so that a display for displaying map information or the like can be inserted into a housing accommodated in a dash box.

When the above-mentioned ACC forced cutoff circuit 101 is applied to such a navigation device, when the ignition switch is switched from the ACC position to the OFF position in a state where the display is not inserted into the housing, the display is turned off. The internal power supply 100 is forcibly shut off without being inserted into the unit.

In order to prevent such a state, AC
The C forced cutoff circuit 101 may be deleted and a circuit configuration as shown in FIG. 4B may be adopted.
There is a problem that it is not possible to take measures against the software runaway of 2.

SUMMARY OF THE INVENTION In view of the above, the present invention provides a countermeasure against software runaway of a power supply monitoring microcomputer, and allows a display to be inserted into a housing when an ignition switch is switched from an ACC position to an OFF position. The purpose is to:

[0007]

In order to achieve the above object, according to the first aspect of the present invention, ON / OFF control of voltage supply from a voltage source (11) to an internal power supply (10) provided in a navigation device is provided. Switching means (1
2) and a power supply monitoring microcomputer (13) for outputting a power supply control signal used for ON / OFF control of the switching means
And the ignition switch is in the ACC position or ON
When the ignition switch is switched from the ACC position to the OFF position based on the ACC signal whose output level changes depending on whether the switch is in the OFF position or the OFF position, the switching means is activated regardless of the power control signal output by the power monitoring microcomputer. ACC forced cutoff circuit (1
4) When the ignition switch is turned off from the ACC position
When switched to the F position, the ACC forced cutoff circuit is provided with a forced cutoff extension circuit (13) for extending the forced cutoff of the switching means for a predetermined time.

As described above, the switching means is forcibly cut off by the ACC forcible shut-off circuit, so that a soft runaway countermeasure for the power supply monitoring microcomputer is achieved. Even if the display is switched to, the voltage supply to the internal power supply can be prevented from being forcibly cut off for a predetermined period after the switching, and the display (1) is inserted into the housing (2) during that period. can do.

For example, as set forth in claim 2, the forced cut-off extension circuit is configured to output an ON drive signal for turning on the switching means to the ACC forced cut-off circuit for a predetermined period. While the ON drive signal is being input, the switching means is not forcibly shut off.

According to the third aspect of the present invention, the switching means (12) for controlling ON / OFF of the voltage supply from the voltage source (11) to the internal power supply (10) provided in the navigation apparatus, and the switching means. ON / OF
A control unit (13) that outputs an ON / OFF signal for performing F control
The control unit switches the ignition switch from the ACC position to the OFF position based on an ACC signal whose output level changes depending on whether the ignition switch is at the ACC position, the ON position, or the OFF position. In this case, an OFF signal for forcibly shutting off the switching means is output after a lapse of a predetermined period from the switching.

Thus, when the ignition switch is set to A
If the switching means is forcibly shut off after a lapse of a predetermined period after being switched from the CC position to the OFF position,
The same effect as the first aspect can be obtained.

The reference numerals in parentheses of the above-mentioned means indicate the correspondence with the concrete means described in the embodiments described later.

[0013]

FIG. 1 shows a navigation device to which a power supply control device according to an embodiment of the present invention is applied. This figure shows the operation of the navigation device.

A power supply control device according to an embodiment of the present invention is applied to a navigation device called an in-dash type as shown in FIG. This in-dash type navigation device includes a display 1 on which map information and the like are displayed, and a housing 2 accommodated in a dash box provided on an instrument panel of the vehicle. A window 3 is formed in the housing 2, and the display 1 is used when the navigation device is not used.
Are driven by a motor or the like (not shown) and inserted into the window portion 3. Specifically, when the navigation device is not used, after the display 1 is folded as shown by the arrow in FIG. 1A, the display 1 is inserted into the window 3 as shown in FIG. Then, the display 1 is completely accommodated in the window 3 as shown in FIG.

A housing opening 4 is formed below the window 3 in the housing 2, and an information recording medium 5 such as a CD or DVD storing map information or the like is housed through the housing opening 4. I can do it. Then, the information stored in the information recording medium 5 is read by the read head in the housing 2, and the information content is displayed on the display 1.

The power supply control device according to the embodiment of the present invention is built in the housing 2 of the navigation device thus configured. FIG. 2 shows a schematic configuration of the power supply control device. Hereinafter, the power supply control device will be described with reference to FIG.

The internal power supply 10 provided in the navigation device includes a constant voltage source (+ B power supply) provided in the vehicle.
Voltage supply is made from 11. The power supply control device performs ON / OFF control of a power supply switch 12 as switching means for controlling the voltage supply to the internal power supply 10.

The power supply control device includes a power supply monitoring microcomputer 13 for controlling the power supply of the navigation device, and an ignition switch provided in the vehicle being turned off from the ACC position.
A circuit for detecting the switching to the position and forcibly shutting down the internal power supply 10 for supplying a voltage to the navigation device, a ACC forcible shutoff circuit 14, and provided for inserting the display 1 into the housing 2. And an insertion / ejection drive circuit 15. Each of these components 13 to 15
A control unit in the power supply control device is configured by the control unit.

The power supply monitoring microcomputer 13 turns on / off the power supply switch 12 based on the user's ON / OFF operation of the navigation device driving switch and the switching of the ignition switch from the ACC position to the OFF position.
A power control signal corresponding to the OFF signal is output.

The ACC forced cutoff circuit 14 forcibly turns the power switch 12 on based on an ACC signal whose output level changes depending on whether the ignition switch is in the ACC position (or ON position) or has been switched to the OFF position.
It generates an OFF signal for FF. This AC
Even if soft runaway of the power monitoring microcomputer 13 occurs due to the C forced cutoff circuit 14, the power switch 12 can be reliably turned off when the ignition switch is switched from the ACC position to the OFF position, resulting in unnecessary power consumption. The battery can be prevented from running down. In the present embodiment, the ACC signal is at Hi level when the ignition switch is at the ACC position (or ON position), and is at L level when the ignition switch is switched to the OFF position.
ow level.

The ACC forced cutoff circuit 14 outputs an OR circuit 16 to which an ACC cutoff signal and a control signal output from the insertion / ejection drive circuit 15 are input, an output signal of the OR circuit 16 and the power supply monitoring microcomputer 13 output. And an AND circuit 17 to which a power control signal is input.
The power switch 12 is finally turned ON / OFF from the circuit 17
An ON / OFF control signal for controlling is output.

The insertion / ejection drive circuit 15 generates an operation trigger signal obtained based on the ACC signal, for example, an ON drive signal for turning on the power switch 12 for a predetermined period based on the fall of the ACC signal; In other words, it serves as a forced cutoff extension circuit that extends the forced cutoff of the power switch 12 by the ACC forced cutoff circuit 14 for a predetermined period. FIG. 3 shows an example of a circuit configuration of the insertion / ejection drive circuit 15. This insertion / ejection drive circuit 15
For example, a semiconductor chip 18 of TC74HC123 manufactured by Toshiba Corporation
Is configured using When the operation trigger signal is input to the A-bar (-) terminal, the semiconductor chip 18 outputs a Hi-level signal from the Q terminal for a predetermined period from the input, and the internal power supply 10 and the Rx / Cx terminal and the resistor 19 and the Rx / Cx terminal and C
It is configured such that the period during which the Hi level signal is output can be adjusted based on the time constant of the capacitor 20 arranged between the x terminal.

Next, the operation of the power supply control device thus configured will be described. First, when the ignition switch is at the ACC position (or ON position), the power supply monitoring microcomputer 13 generates a power supply control signal based on ON / OFF of the navigation device drive switch by the user. On the other hand, at this time, since the ACC signal is at the Hi level, the output signal of the OR circuit 16 becomes Hi.
Level. Therefore, the power control signal of the power monitoring microcomputer 13 is directly used as an ON / OFF control signal of the AND circuit 17, and the power switch 12 is driven based on the power control signal of the power monitoring microcomputer 13.

On the other hand, when the ignition switch is switched from the ACC position to the OFF position, the ACC signal becomes Hi.
It changes from level to low level. Then, based on the fall of the ACC signal, the insertion / ejection drive circuit 15 outputs a Hi-level signal for a predetermined period. For this reason, even if the ACC signal changes to the low level, the OR circuit 1 remains in the period in which the Hi-level signal is output from the insertion / ejection drive circuit 15.
The output signal of No. 6 becomes Hi level, and during this period, the power switch 12 is not forcibly shut off. Therefore, during this period, a voltage is supplied to the internal power supply 10 and the display 1 is inserted into the housing 2. Then, after a lapse of a predetermined period, the output signal of the OR circuit 16 becomes Low level,
The ON / OFF control signal of the AND circuit 17 also becomes Low level (OFF signal), and the power switch 12 is forcibly shut off.

As described above, the power supply switch 12 is forcibly cut off by the ACC forcible cutoff circuit 14, so that the power supply monitoring microcomputer 13 is provided with the insertion / ejection drive circuit 15 while taking measures against soft runaway.
Even if the display is switched from the CC position to the OFF position, the voltage supply to the internal power supply 10 is not forcibly cut off for a predetermined period after the switching, so that the display 1 is inserted into the housing unit 2 during the period. Can be done.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an operation state of a navigation device to which a power supply control circuit according to a first embodiment of the present invention is applied.

FIG. 2 is a diagram showing a schematic configuration of a power supply control circuit built in the navigation device shown in FIG.

FIG. 3 is a diagram showing a circuit configuration example of an insertion / ejection drive circuit 15 shown in FIG. 2;

FIG. 4 is a diagram showing a schematic configuration of a power supply control circuit built in a conventional navigation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Display, 2 ... Housing part, 5 ... Information recording medium, 1
0: internal power supply, 12: power switch, 13: power supply monitoring microcomputer, 14: ACC forced cutoff circuit, 15: insertion / ejection drive circuit, 16: OR circuit, 17: AND circuit.

Claims (3)

[Claims] A display for displaying information (1)
And a housing unit (2) that houses an information recording medium (5) in which the information is stored, reads the information stored in the information recording medium, and displays the information on the display. A power supply control device for use in a navigation device configured to be capable of inserting the display into the housing portion and discharging the display to the outside of the housing portion, comprising: A switching unit (12) for controlling ON / OFF of a voltage supply to an internal power supply (10) provided; a power monitoring microcomputer (13) for outputting a power control signal used for ON / OFF control of the switching unit; The output level changes based on whether the ignition switch is in the ACC position, the ON position, or the OFF position. , When the ignition switch is switched to the OFF position from the ACC position,
An ACC forced shutoff circuit for forcibly shutting off the switching means irrespective of a power control signal output by the power supply monitoring microcomputer; and an ACC forced cutoff circuit when the ignition switch is switched from an ACC position to an OFF position. A power supply control device, comprising: a forced cutoff extension circuit (13) for extending the forced cutoff of the switching means for a predetermined time. 2. The forced cut-off extension circuit outputs an ON drive signal for turning on the switching means to the ACC forced cut-off circuit during the predetermined period. The power supply control device according to claim 1, wherein the switching unit is not forcibly shut off during a period in which the drive signal is being input. 3. A display for displaying information (1)
And a housing unit (2) that houses an information recording medium (5) in which the information is stored, reads the information stored in the information recording medium, and displays the information on the display. A power supply control device for use in a navigation device configured to be capable of inserting the display into the housing portion and discharging the display to the outside of the housing portion, comprising: A switching unit (12) for performing ON / OFF control of voltage supply to an internal power supply (10) provided; and an ON / OFF unit for performing ON / OFF control of the switching unit.
A control unit (13 to 15) for outputting an OFF signal, wherein the control unit is configured to output the OFF signal based on an ACC signal whose output level changes depending on whether an ignition switch is in an ACC position, an ON position, or an OFF position. When the ignition switch is switched from the ACC position to the OFF position, an OFF signal for forcibly shutting off the switching means is output after a lapse of a predetermined period from the switching.