JP2586696Y2 - Vehicle load control device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle load control device in which the operation of a vehicle load is controlled by a control circuit including a central processing unit.

[0002]

2. Description of the Related Art As an example of this kind of vehicle load control device, there is known a remote control device capable of remotely controlling the starting of an automobile engine. That is, this remote control device is configured to operate an engine starter motor, which is a vehicle load, by a radio signal from a terminal device carried by a driver for the purpose of performing an engine warm-up operation. Specifically, the remote control device is configured by providing, on the vehicle side, a receiver for receiving the radio signal and a control circuit for forming an energizing circuit for a starter motor based on the received signal. However, since the control circuit requires complicated control such as analysis of an encryption code included in a radio signal, the control circuit is generally configured mainly by a central processing unit.

In this case, since the central processing unit constituting the control circuit is configured to obtain power from a vehicle-mounted battery, means for preventing malfunction due to the power supply voltage falling below the operation guarantee voltage is required. Becomes For this reason, conventionally, a low-voltage detection circuit that generates a reset signal when the power supply voltage falls below a preset reset level is provided, and the central processing unit is held in an initialized state when the reset signal is output. To prevent malfunction.

[0004]

When the starter motor is energized, a relatively large load current flows and the power supply voltage of the central processing unit temporarily drops. For this reason, for example, in a situation where the capacity of the vehicle-mounted battery is reduced due to aging or the influence of the ambient temperature, the power supply voltage is lower than the reset level set in the low-voltage detection circuit when the starter motor is energized. May temporarily decrease. When such a situation occurs, in the conventional configuration, the central processing unit is initialized by the reset signal output from the low-voltage detection circuit. In spite of the state in which the motor can be driven sufficiently, there arises a problem that the energization control of the starter motor becomes impossible.

The present invention has been made in view of the above circumstances, and has as its object to provide a central processing unit in a control circuit even under a situation where a relatively large load current flows and a power supply voltage temporarily drops. It is an object of the present invention to provide a load control device for a vehicle that can guarantee the normal operation of the device and can always reliably control the operation of the vehicle load by the central processing unit. .

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is based on the premise that the operation of a vehicle load is controlled by a control circuit including a central processing unit. In the above, after providing a clock controller configured to be able to switch the frequency of the system clock signal for the central processing unit in a plurality of stages,
When the control circuit drives a vehicle load in which a load current flows over a set level, the frequency of a system clock signal output from the clock controller is reduced in advance, and the frequency reduction state is maintained for a predetermined period. It has a structure (claim 1).

In a vehicle load control device having the same premise as described above, a clock controller configured to switch the frequency of a system clock signal for the central processing unit in a plurality of stages, and a power supply voltage A voltage detecting means for generating a low-voltage alarm signal when the voltage falls below a predetermined lower limit level. When an alarm signal is output, a state in which the frequency of the system clock signal output from the clock controller is reduced may be maintained for a predetermined period (claim 2).

[0008]

In the vehicle load control device according to the present invention, when driving the vehicle load in which the load current flows over the set level, the control circuit reduces the frequency of the system clock signal output from the clock controller in advance. The state is maintained for a predetermined period. For this reason, the clock frequency of the central processing unit in the control circuit is reduced. In this case, since the operable voltage of the central processing unit has a general property that the lower the clock frequency is, the lower the power supply voltage temporarily when driving the vehicle load as described above. In this case, the operable voltage of the central processing unit is also temporarily reduced. Therefore, even in a situation where the power supply voltage temporarily decreases, the normal operation of the central processing unit can be guaranteed, and the operation control of the vehicle load by the central processing unit can always be reliably performed. Become like

In the vehicle load control device according to the second aspect,
When the power supply voltage falls below the predetermined lower limit level, the voltage detecting means generates a low voltage alarm signal. When driving the vehicle load in which the load current flows over the set level in the state where the low voltage detection signal is output as described above, the control circuit operates in a state where the frequency of the system clock signal output from the clock controller is reduced. It is kept for a predetermined period. For this reason, the clock frequency of the central processing unit in the control circuit is reduced, and therefore, even in this case, the normal operation of the central processing unit under a situation where the power supply voltage temporarily decreases. The operation can be guaranteed, and the operation control of the vehicle load by the central processing unit can always be surely performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a remote control device for an automobile will be described below with reference to FIGS. In FIG. 1 showing an electric configuration, a portable transceiver 1 is carried by a driver of an automobile, and in accordance with the operation, an operation command signal Sa of a predetermined code for instructing start and stop of an engine and an operation. Stop command signal Sb,
An unlock command signal Sc and a lock command signal Sd of a predetermined code for commanding unlocking and locking of a plurality of vehicle door lock mechanisms 2 as vehicle loads are selectively generated, and the generated signals are transmitted to the antenna 1a. It is configured to transmit by a radio signal transmitted through. Further, the portable transceiver 1 has a function of displaying the contents of reception via the antenna 1a on a display (not shown).

The transmission / reception unit 3 is installed in a place where the radio wave reception condition is good in the interior of the vehicle, receives the command signals Sa to Sd from the portable transceiver 1 via the antenna 3a, and will be described later. It has a function of supplying a one-chip CPU (hereinafter simply referred to as CPU) 5 in the control circuit 4 and feeding back a start completion signal Sk supplied from the CPU 5 to the portable transceiver 1 through the antenna 3a. The CPU 5 includes a central processing unit (not shown) according to the present invention, a clock controller 23 described later, a memory unit (not shown), and the like. In the portable transceiver 1, when the start completion signal Sk is received, an indication that the engine has been started is displayed by a display (not shown).

The power supply circuit 6 is supplied with power from a positive power supply terminal + B of a not-shown vehicle-mounted battery through a diode 7 for preventing reverse connection, and supplies its output to the transmission / reception unit 3 and the control circuit 4 and the like. It has become.

The engine start detection circuit 8 detects whether or not the engine has been started normally based on the engine speed, the state of the ignition device, and the like. A start signal Sf is provided via the input circuit 9.

The ACC relay 10 connects the accessory circuit of the vehicle to the positive power supply terminal + B of the vehicle battery in the operating state, and the IG relay 11 connects the ignition circuit of the vehicle to the positive power terminal + B in the operating state. Has become. In addition, the starter relay 12 is configured to form an energizing path for the engine starter motor 13 as a vehicle load through the plus power supply terminal + B in the operating state. In this case, the above relays 10-1
2 is operated by the CPU 5 through the driver 14.

The parking brake switch 15 generates a brake operation signal S1 in a state where the parking brake of the vehicle is in the operating position.
6 is the case where the shift position of the car is the parking position (however, in the case of an automatic transmission,
The parking signal S2 is generated when the vehicle is in the neutral position in the case of a manual transmission, the hood switch 17 generates the hood closing signal S3 when the hood of the vehicle is closed, and the door lock detection switch 18 is The door lock signal S4 is generated when all the door lock mechanisms 2 are in the locked state. The signals S1 to S4 are provided to the CPU 5 via input circuits 19 to 22, respectively.

The clock controller 23 incorporated in the CPU 5 is for generating a stem clock signal using the crystal oscillator 23a, and the frequency of the system clock signal is adjusted in two steps based on the program of the CPU 5. It can be switched to More specifically, in this embodiment, for example, the switching frequency can be switched between 1 MHz corresponding to the clock frequency in the steady state of the CPU 5 and 250 KHz, which is a quarter of that frequency. May be switched to.

The operation of the door lock mechanism 2 is controlled through a driver 24 in response to a command signal from the CPU 5. The CPU 5 includes a power supply circuit 6.
A watchdog timer 25 of a well-known configuration, which is supplied with power from an external device, is additionally provided.

Hereinafter, the control contents of the CPU 5 and the operation related thereto will be described with reference to FIG. 2 (a), (b), (c),
(D) is a timing showing the fluctuation state of the output voltage of the vehicle-mounted battery, the switching state of the frequency of the system clock signal output from the clock controller 23, the formation state of the ignition circuit by the IG relay 11, and the energization state of the starter motor 13, respectively. It is a chart.

That is, when the CPU 5 receives the operation command signal Sa from the portable transceiver 1 through the transmission / reception unit 3, the CPU 5 determines that the start signal Sf has not been input, the brake operation signal S1, the parking signal S2, and the hood closing signal. S3 and the engine start program are executed on the premise that all the door lock signals S4 have been input.

In this engine start program, first, the IG relay 11 is operated to form an ignition circuit (timing t1 in FIG. 2). Thereafter, at a timing t2 after a predetermined time has elapsed, the system from the clock controller 23 is started. The frequency of the clock signal is reduced to a quarter frequency (250 KHz) of the steady state, and the starter relay 12 is operated to start the starter motor 1.
The engine is started by forming the third current path.

In this case, the CPU 5 holds the state in which the frequency of the system clock signal is reduced as described above for a predetermined time T0 longer than the period during which a relatively large starting current flows through the starter motor 13, and reduces the frequency. During a period (that is, a period during which the program execution speed is reduced), for example, execution of a program related to a transmission / reception function via the transmission / reception unit 3, a program related to operation control of the door lock mechanism 2, and a program related to a display function (not shown) Cancel and secure the execution speed of the remaining programs.

In short, when the operation command signal Sa is transmitted from the portable transceiver 1, the engine has not been started, the parking brake is operating, and the shift position of the vehicle is at the parking position. , The hood of the car is closed,
The engine is started on condition that all the door lock mechanisms 2 are locked.

In this case, when a relatively large current flows through the starter motor 13, as shown in FIG.
The output voltage of the in-vehicle battery (and eventually the power supply voltage of the CPU 5) temporarily decreases, and in some cases, the power supply voltage of the CPU 5 may fall below the operation guarantee voltage. However, the operable voltage of the CPU 5 is
In contrast to the general characteristic that the lower the clock frequency is, the lower the clock frequency is, the longer the predetermined time T0 elapses after the starter motor 13 is energized,
Since the clock frequency of U5 is reduced to 1/4 of the steady state, when the power supply voltage of the CPU 5 temporarily decreases as described above, the operable voltage of the CPU 5 also temporarily decreases.

Therefore, even when the power supply voltage of the CPU 5 falls below the operation guarantee voltage at the steady clock frequency, the normal operation of the CPU 5 is guaranteed.

On the other hand, if the start signal Sf is input from the engine start detecting circuit 8 after the engine is started as described above (when the engine is started normally), the CPU 5 carries the portable telephone through the transmission / reception unit 3. Type transceiver 1
The start-up completion signal Sk is fed back to the controller and the current path of the starter motor 13 is cut off. Then, the operation of the starter motor 13 is stopped and the portable transceiver 1 is stopped.
In, the received content is displayed on a display (not shown), and the operator can confirm that the engine has been correctly started based on such a display.

When the state in which the energizing path of the starter motor 13 is formed is continued for a predetermined upper limit time or more, the CPU 5 temporarily shuts off the energizing path. Re-execute the engine start operation. When the CPU 5 receives the operation stop command signal Sb from the portable transceiver 1 through the transmission / reception unit 3 while the engine is operating,
The engine is stopped by stopping the operation of the G relay 11 to cut off the ignition circuit. Furthermore, CP
U5 is an unlock command signal S from the portable transceiver 1
When the lock command signal Sd is received, the door lock mechanism 2 is unlocked, and when the lock command signal Sd is received, the door lock mechanism 2 is locked.

However, according to the configuration of the present embodiment, even when a relatively large load current flows when the engine is started by remote control and the power supply voltage of the CPU 5 is temporarily reduced, the CPU 5 is not operated. Normal operation can be guaranteed, and the engine start control by the CPU 5 can always be performed reliably. In this case, in order to obtain the above-described effects, the clock controller 23 is configured to be capable of switching the output frequency, and the control program of the CPU 5 need only be slightly changed. This eliminates the need for a circuit and simplifies the entire hardware configuration, and also reduces the dark current, which is very useful when a battery is used as a driving source.

In the above embodiment, the state in which the clock frequency of the CPU 5 is reduced is held for the predetermined time T0. However, for example, when the start signal Sf is input from the engine start detection circuit 8, the clock frequency is reduced. It is good also as a structure which cancels the reduction state of.

FIGS. 3 and 4 show a second embodiment of the present invention. Only the portions different from the first embodiment will be described below. In FIG. 3, the watchdog timer 26 has a low-voltage reset function in addition to a normal watchdog function, and its power supply voltage (output voltage of the power supply circuit 6) is a predetermined reset level, for example, 4.5 V or less. Generates a reset signal Sx when the
5 is provided to the reset terminal RST.

Low voltage monitoring circuit 27 as voltage detecting means
Is provided to detect, for example, the output voltage of the plus power supply terminal + B of the vehicle-mounted battery (a configuration that detects the output voltage of the power supply circuit 6 is also possible), and always outputs a high-level signal. When the detected voltage falls below a predetermined lower limit level, a low voltage alarm signal Sv composed of a low level signal is generated and supplied to the CPU 5.

In the following, the control contents of the CPU 5 in this embodiment and the operation related thereto will be described with reference to FIG. In addition, FIG.
(B), (c), (d), and (e) show the fluctuation state of the output voltage of the vehicle-mounted battery, the signal output state of the low-voltage monitoring circuit 27, and the switching of the frequency of the system clock signal output from the clock controller 23. State, IG relay 11
4 is a timing chart showing a state of forming an ignition circuit and a state of energization of a starter motor 13 respectively.

That is, when the CPU 5 receives the operation command signal Sa from the portable transceiver 1 through the transmission / reception unit 3, the CPU 5 determines that the start signal Sf has not been input, the brake operation signal S1, the parking signal S2, and the hood closing signal. S3 and the engine start program are executed on the premise that all the door lock signals S4 have been input.

In this engine start program, first, the IG relay 11 is operated to form an ignition circuit (timing t1 in FIG. 4), and thereafter, at a timing t2 when a predetermined time has elapsed, the starter relay 1 is started.
2 is operated to form an energizing path for the starter motor 13 to start the engine. At this time, when the low-voltage warning signal Sv is output from the low-voltage monitoring circuit 27 (timing t3), that is, when the output voltage of the vehicle-mounted battery falls below the lower limit level, the CPU 5 receiving the low-voltage warning signal Sv , Clock controller 23
The frequency of the system clock signal from the
(250 KHz).

In this case, the CPU 5 keeps the state in which the frequency of the system clock signal is reduced as described above only during the output period of the low-voltage warning signal Sv, and also during the frequency reduction period (that is, when the program execution speed is reduced). During the period of the fall, the execution of the program related to the transmission / reception function via the transmission / reception unit 3, the program related to the operation control of the door lock mechanism 2, and the execution of the program related to the display function (not shown) is canceled, and the execution of the remaining programs is executed. Secure speed.

Thereafter, when the start signal Sf is input from the engine start detection circuit 8, the CPU 5
The start-up completion signal Sk is fed back to the portable transceiver 1 through the transmission / reception unit 3, and the same control as in the first embodiment, such as cutting off the current path of the starter motor 13, is performed.

Accordingly, also in the configuration of the present embodiment, the clock frequency of the CPU 5 is reduced under a situation where a relatively large load current flows when the engine is started by remote control and the power supply voltage of the CPU 5 is temporarily reduced. Thus, the normal operation of the CPU 5 can be guaranteed, and the engine start control by the CPU 5 can always be reliably performed.

In each of the above embodiments, the one-chip CPU 5 having the built-in clock controller 23 is used, but a CPU having an external clock controller is used.
It is good also as a structure using. Further, in each of the above embodiments, an automobile engine is taken as an example of a vehicle load to be controlled. However, the present invention is also applicable to an electric vehicle, and in this case, a relatively large load such as an air conditioner is used. An automobile load through which a load current flows is to be controlled.

[0038]

According to the present invention, as is apparent from the above description, in the vehicle load control device for controlling the operation of the vehicle load by the control circuit including the central processing unit, the load current is set to the set level. During the driving period of the vehicle load flowing above, since the clock frequency of the central processing unit is reduced, even under a situation where a relatively large load current flows and the power supply voltage temporarily decreases, This has a beneficial effect that normal operation of the central processing unit can be guaranteed, and operation control of the vehicle load by the central processing unit can always be reliably performed.

[Brief description of the drawings]

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

FIG. 2 is a timing chart for explaining the operation.

FIG. 3 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.

FIG. 4 is a diagram corresponding to FIG. 2;

[Explanation of symbols]

In the figure, 4 is a control circuit, 5 is a one-chip CPU, 6 is a power supply circuit, 13 is a starter motor (vehicle load), 23 is a clock controller, and 27 is a low voltage monitoring circuit (voltage detecting means).

Continuation of the front page (72) Inventor Toshihisa Toda 1 Noda, Toyota, Oguchi-machi, Oguchi-machi, Niwa-gun, Aichi Prefecture Inside Tokai Rika Electric Works, Ltd. (56) References JP-A-2-245446 (JP, A) JP-A Sho 61-6672 (JP, A) Japanese Utility Model Hei 3-51174 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B60R 16/02 660 F02N 11/08

Claims (2)

(57) [Scope of request for utility model registration] 1. A load control device for a vehicle that controls operation of a vehicle load by a control circuit including a central processing unit, wherein a frequency of a system clock signal for the central processing unit can be switched in a plurality of stages. With the provided clock controller, the control circuit reduces the frequency of a system clock signal output from the clock controller in advance when driving a vehicle load in which a load current flows over a set level. A load control device for a vehicle, wherein the frequency reduction state is maintained for a predetermined period. 2. A vehicle load control device for controlling the operation of a vehicle load by a control circuit including a central processing unit, wherein a frequency of a system clock signal for the central processing unit can be switched in a plurality of stages. The control circuit includes a clock controller configured as described above, and a voltage detection unit that generates a low-voltage alarm signal when a power supply voltage falls below a predetermined lower limit level. When driving the load, when the low-voltage alarm signal is output, a state in which the frequency of the system clock signal output from the clock controller is reduced is maintained for a predetermined period. A load control device for a vehicle, comprising: