JPH0717660U - Vehicle load control device - Google Patents

Abstract

(57) [Abstract] [Purpose] To guarantee the normal operation of the central processing unit in the control circuit even under the situation where the power supply voltage temporarily drops in response to the driving of the vehicle load. [Structure] The clock controller 23, which determines the clock frequency of the CPU 5 in the control circuit 4, is configured to switch the frequency of the system clock signal in two steps based on the program of the CPU 5. CPU5
When the engine starter motor 13 is driven, the system clock signal output from the clock controller 23 is kept in a reduced frequency for a predetermined time. In this case, the operable voltage of the CPU 5 has a general property that it decreases as the clock frequency decreases.
When the clock frequency of 5 is reduced, the CPU
The operable voltage of 5 also temporarily drops.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle load control device in which operation control of a vehicle load is performed by a control circuit including a central processing unit.

[0002]

[Prior art]

 As an example of this type of vehicle load control device, a remote control device is known in which start control of an automobile engine can be performed by remote control. That is, this remote control device is configured to operate the engine starter motor, which is the vehicle load, by the radio signal from the terminal device carried by the driver for the purpose of warming up the engine. . Specifically, the remote control device is configured by providing the vehicle side with a receiver that receives the radio wave signal and a control circuit that forms an energization circuit of the 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, it is generally composed mainly of a central processing unit.

In this case, since the central processing unit that constitutes the control circuit has a configuration in which the power source is obtained from the vehicle-mounted battery, there is a means for preventing malfunction due to the power source voltage dropping below the guaranteed operating voltage. Will be needed. For this reason, in the past, a low voltage detection circuit that generates a reset signal when the power supply voltage drops below a preset reset level is provided, and the central processing unit is initialized when the reset signal is output. To prevent malfunctions.

[0004]

[Problems to be solved by the device]

 By the way, 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, under the condition that the capacity of the on-board battery is reduced due to deterioration over time or the influence of ambient temperature, for example, when the starter motor is energized, the power supply voltage is reset to the reset level set in the low voltage detection circuit. The following may be temporarily reduced. 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, so the phenomenon of power supply voltage drop is temporary. In spite of the fact that the starter motor can be driven sufficiently, it is impossible to control the energization of the starter motor.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a central control circuit in a control circuit even when a relatively large load current flows and the power supply voltage temporarily drops. (EN) A load control device for a vehicle, which is capable of guaranteeing normal operation of the arithmetic processing device, and having the effect that the operation control of the load for the vehicle by the central processing unit can be always performed reliably. Especially.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention provides a vehicle load control device on the premise that operation control of a vehicle load is performed by a control circuit including a central processing unit. If a clock controller configured to switch the frequency of the system clock signal for the vehicle in a plurality of stages is provided and the control circuit drives a vehicle load in which the load current flows at a set level or more, The frequency of the system clock signal output from the controller is reduced in advance, and the reduced frequency state is held for a predetermined period (claim 1).

Further, in a vehicle load control device having the same precondition as above, 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, and a power supply voltage. Voltage detection means for generating a low voltage warning signal when the load current falls below a predetermined lower limit level, the control circuit controls the low voltage in the case of driving a vehicle load in which a load current flows above a set level. In the case where the voltage alarm signal is output, the system controller may output the system clock signal output from the clock controller in a state in which the frequency is reduced for a predetermined period (claim 2). ).

[0008]

[Action]

 In the vehicle load control device according to claim 1, when driving a vehicle load in which a load current flows at a set level or more, the control circuit sets a state in which the frequency of the system clock signal output from the clock controller is reduced in advance. It will be retained only for a specified period. Therefore, 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 the general property that it decreases as the clock frequency decreases, the power supply voltage temporarily decreases when driving the vehicle load as described above. In this case, the operable voltage of the central processing unit will also temporarily drop. Therefore, it is possible to guarantee the normal operation of the central processing unit even under the situation where the power supply voltage is temporarily reduced, and it is possible to always reliably and reliably control the operation of the vehicle load by the central processing unit. Like

In the vehicle load control device according to the second aspect of the present invention, when the power supply voltage becomes equal to or lower than the predetermined lower limit level, the voltage detecting means generates the low voltage alarm signal. When driving a vehicle load in which a load current flows above a set level while the low voltage detection signal is output in this way, the control circuit reduces the frequency of the system clock signal output from the clock controller. It will be held only 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 power supply voltage is temporarily reduced, and the central processing unit operates normally. The operation can be guaranteed, and the operation control of the vehicle load by the central processing unit can be always performed reliably.

[0010]

【Example】

 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. 1 and 2. In FIG. 1 showing an electrical configuration, a portable transceiver 1 is carried by a driver of an automobile, and an operation command signal Sa of a predetermined code for instructing start and stop of an engine is issued according to the operation. And an operation stop command signal Sb, and an unlock command signal Sc and a lock command signal Sd having predetermined codes for commanding unlocking and locking of a plurality of vehicle door lock mechanisms 2 as vehicle loads. At the same time, the generated signal is transmitted as a radio signal through the antenna 1a. The portable transceiver 1 has a function of displaying the content received through the antenna 1a on a display (not shown).

The transmission / reception unit 3 is installed in a place where the electric wave reception condition is good in the passenger compartment of the automobile, receives the command signals Sa to Sd from the portable transceiver 1 through the antenna 3a, and will be described later. The control circuit 4 has a function of feeding it to a one-chip CPU (hereinafter, simply referred to as CPU) 5 in the control circuit 4 and feeding back a start completion signal Sk fed from the CPU 5 to the portable transceiver 1 through the antenna 3a. The CPU 5 is configured to include a central processing unit (not shown) according to the present invention, a clock controller 23, which will be described later, and a memory unit (not shown). In addition, the portable transceiver 1 is configured such that when the start completion signal Sk is received, a display (not shown) indicates that the engine has started.

The power supply circuit 6 is adapted to be supplied with power from a positive power supply terminal + B of an on-vehicle battery (not shown) through a diode 7 for preventing reverse connection, and its output is applied to the transmitting / receiving 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. The starting signal Sf is supplied via the input circuit 9.

The ACC relay 10 connects the accessory circuit of the automobile to the plus power supply terminal + B of the vehicle battery in the operating state, and the IG relay 11 connects the ignition circuit of the automobile to the plus power supply terminal + B in the operating state. It is configured to do. Further, the starter relay 12 is configured to form an energization 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 relays 10 to 12 are operated by the CPU 5 through the driver 14.

The parking brake switch 15 generates a brake operation signal S1 while the parking brake of the vehicle is in the operating position, and the shift position switch 16 controls the shift position of the vehicle in the parking position (however, in the case of an automatic transmission). Yes, in the case of a manual transmission, the parking signal S2 is generated in the neutral position), the bonnet switch 17 generates the bonnet closing signal S3 in the state in which the hood of the automobile is closed, and the door lock detection switch 18 The door lock signal S4 is generated when the door lock mechanism 2 of the vehicle is all locked. The signals S1 to S4 are applied to the CPU 5 via the 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 23 a, and controls the frequency of the system clock signal to 2 by using the program of the CPU 5. The structure is such that it can be switched to a stage. Specifically, in this embodiment, for example, the configuration is such that the 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 frequency thereof, but a lower frequency. You may switch to.

The door lock mechanism 2 is configured so that its operation is controlled through a driver 24 in response to a command signal from the CPU 5. Further, the CPU 5 is provided with a well-known watchdog timer 25 which is supplied with power from the power supply circuit 6.

Now, the control content of the CPU 5 and the operation related thereto will be described below with reference to FIG. 2 (a), (b), (c), and (d) show 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, and the IG relay 11. 3 is a timing chart showing the formation state of the ignition circuit and the energization state of the starter motor 13.

That is, when the CPU 5 receives the operation command signal Sa from the portable transceiver 1 through the transmission / reception unit 3, the start signal Sf is not input, the brake operation signal S1, the parking signal S2, and the bonnet closing. The program for starting the engine is executed on condition that the signal S3 and the door lock signal S4 are all input.

In this engine starting program, first, the IG relay 11 is operated to form an ignition circuit (timing t1 in FIG. 2), and thereafter, at a timing t2 when a predetermined time has elapsed, the clock controller 23 The frequency of the system clock signal is reduced to 1/4 of the steady state frequency (250 KHz), and the starter relay 12 is operated to form the energization path of the starter motor 13 to start the engine.

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 in which a relatively large starting current flows in the starter motor 13, and During the reduction period (that is, the period when the program execution speed decreases), for example, the programs related to the transmission / reception function through the transmission / reception unit 3, the programs related to the operation control of the door lock mechanism 2, and the display functions not shown. Cancel the execution of the executed program 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 in the parking position. That is, the engine is started on condition that the vehicle's bonnet is closed and the door lock mechanism 2 is all locked.

In this case, when a relatively large current flows through the starter motor 13, as shown in FIG. 2A, the output voltage of the vehicle-mounted battery (and thus the power supply voltage of the CPU 5) temporarily drops. In some cases, the power supply voltage of the CPU 5 may drop below the guaranteed operating voltage. However, while the operable voltage of the CPU 5 has a general property that it decreases as the clock frequency thereof decreases, the CPU 5 does not operate until a predetermined time T0 elapses after the starter motor 13 is energized. Since the clock frequency of 1 is reduced to 1/4 of the steady state, when the power supply voltage of the CPU 5 temporarily drops as described above, the operable voltage of the CPU 5 also temporarily drops.

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, when the start signal Sf is input from the engine start detection circuit 8 after the engine is started as described above (when the engine is normally started), the CPU 5 sends the signal through the transmission / reception unit 3. A start completion signal Sk is fed back to the portable transceiver 1, and the energization path of the starter motor 13 is cut off. Then, the starter motor 13 is stopped, and in the portable transceiver 1, the received contents are displayed on the display (not shown), and the operator correctly starts the engine based on such display. You will be able to confirm that.

It should be noted that the CPU 5 once shuts off the energization path when the energization path of the starter motor 13 is maintained for a predetermined upper limit time or longer, and when a certain period of time elapses thereafter, the above-mentioned Re-execute such an engine starting operation. Further, when the CPU 5 receives the operation stop command signal Sb from the portable transceiver 1 through the transceiver unit 3 while the engine is operating, the CPU 5 stops the IG relay 11 and shuts off the ignition circuit. To stop the engine. Furthermore, the CPU 5 unlocks the door lock mechanism 2 when receiving the unlock command signal Sc from the portable transceiver 1, and the door lock mechanism 2 when receiving the lock command signal Sd. Lock operation.

However, according to the configuration of the present embodiment described above, even when a relatively large load current flows and the power supply voltage of the CPU 5 temporarily drops when the engine is started by remote control, the CPU 5 does not operate. The normal operation can be guaranteed, and the engine start control by the CPU 5 can always be surely performed. In this case, in order to obtain the above effects, the clock controller 23 is configured to be able to switch the output frequency, and the control program of the CPU 5 need only be slightly modified, so that the low voltage detection that has been conventionally required It eliminates the need for circuits and simplifies the overall hardware configuration. It also reduces dark current, which is very useful when using a battery 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 changed. It is also possible to cancel the reduced state of.

A second embodiment of the present invention is shown in FIGS. 3 and 4, and only the parts 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 the normal watchdog function, and its power supply voltage (output voltage of the power supply circuit 6) is a predetermined reset level, for example, 4.5V. When the voltage drops below, the reset signal S x is generated and applied to the reset terminal RST of the CPU 5.

The low-voltage monitoring circuit 27 as a voltage detecting means is provided so as to detect, for example, the output voltage of the positive power supply terminal + B of the on-vehicle battery (a configuration for detecting the output voltage of the power supply circuit 6 is also possible). The high-level signal is always output, but when the detected voltage becomes lower than the predetermined lower limit level, the low-voltage warning signal Sv including the low-level signal is generated and given to the CPU 5. ing.

Therefore, hereinafter, the control contents of the CPU 5 in this embodiment and the operation related thereto will be described with reference to FIG. 4 (a), 4 (b), 4 (c), 4 (d), and 4 (e), the output voltage of the on-vehicle battery changes, the low voltage monitoring circuit 27 outputs the signal, and the clock controller 23 outputs the data. 3 is a timing chart showing the switching state of the frequency of the system clock signal, the ignition circuit forming state by the IG relay 11, and the energization state of the starter motor 13.

That is, when the CPU 5 receives the operation command signal Sa from the portable transceiver 1 through the transmission / reception unit 3, the start signal Sf is not input, the brake operation signal S1, the parking signal S2, and the bonnet closing. The program for starting the engine is executed on condition that the signal S3 and the door lock signal S4 are all input.

In this engine starting program, first, the IG relay 11 is operated to form an ignition circuit (timing t1 in FIG. 4), and then the starter relay 12 is operated at timing t2 when a predetermined time has elapsed. Then, the energization path of the starter motor 13 is formed 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 on-vehicle battery falls below the lower limit level, the low-voltage warning signal Sv is received. Further, the CPU 5 reduces the frequency of the system clock signal from the clock controller 23 to ¼ of the steady state frequency (250 KHz).

In this case, the CPU 5 holds 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, the program execution speed). During the period when the data is dropped), the execution of programs related to the transmission / reception function via the transmission / reception unit 3, programs related to the operation control of the door lock mechanism 2, and programs related to the display function (not shown) is canceled, and the remaining programs are canceled. Ensure execution speed.

Thereafter, when the start signal Sf is input from the engine start detection circuit 8, the CPU 5 feeds back the start completion signal Sk to the portable transceiver 1 through the transmitting / receiving unit 3 and also starts the starter motor 13 The same control as in the first embodiment, such as shutting off the power supply path, is performed.

Therefore, also in the configuration of this embodiment, the clock frequency of the CPU 5 is lowered under a situation in which 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 lowered. As a result, 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-described embodiments, the one-chip CPU 5 with the built-in clock controller 23 is used, but a CPU with an external clock controller may be used. Further, in each of the above-mentioned embodiments, the automobile engine is taken as an example of the vehicle load to be controlled, but the present invention can also be applied to an electric vehicle. The control target is the automobile load through which a large load current flows.

[0038]

[Effect of device]

 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 vehicle load control device for the vehicle in which the load current flows above the set level is used. Since the clock frequency of the central processing unit is reduced during the load driving period, the central processing unit can be operated even under a situation where a relatively large load current flows and the power supply voltage temporarily drops. This has a beneficial effect that the normal operation of the device can be guaranteed, and the operation control of the vehicle load by the central processing unit can always be surely performed.

[Brief description of 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 view corresponding to FIG.

[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 No. 1 Noda, Toyoda, Oguchi-cho, Niwa-gun, Aichi Prefecture Tokai Rika Electric Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A load control device for a vehicle, wherein a control circuit including a central processing unit controls operation of a load for a vehicle, wherein a frequency of a system clock signal for the central processing unit can be switched in a plurality of steps. With the clock controller configured, the control circuit reduces the frequency of the system clock signal output from the clock controller in advance when driving a vehicle load in which a load current flows at a set level or more. A load control device for a vehicle, which is configured to hold the frequency reduced state for a predetermined period. 2. A load control device for a vehicle, wherein a control circuit including a central processing unit controls operation of a load for a vehicle, wherein a frequency of a system clock signal for the central processing unit can be switched in a plurality of steps. The control circuit includes a clock controller configured and voltage detection means for generating a low-voltage warning signal when the power supply voltage falls below a predetermined lower limit level. In the case where the low voltage warning signal is output in the case of driving the power supply load, the system controller holds the state in which the frequency of the system clock signal output from the clock controller is reduced for a predetermined period. A load control device for a vehicle, which is characterized in that: