JPH0687428A - Power source voltage monitoring device for load - Google Patents

Abstract

PURPOSE:To monitor the applied voltage to a solenoid valve in any period. CONSTITUTION:The electric power of a battery 31 is supplied to a solenoid valve 33 through a relay 34. An output transistor 52 is connected in series between the solenoid valve 33 and the grounding electric potential. The voltage between the solenoid valve 33 and the output transistor 52 is monitored by the first monitor circuit 61, and the signal corresponding to the voltage is supplied into a microcomputer 51. Whereas, the electric power of the battery 31 is supplied to a motor 40 through a relay 39, The voltage between the relay 39 and the motor 40 is monitored by the second monitoring circuit 62, and the signal corresponding to the voltage is supplied to the microcomputer 51. The microcomputer 51 refers the signal supplied from the first monitoring circuit 61 during the period that the solenoid valve 33 is not driven, while the microcomputer 51 refers the signal supplied from the second monitor circuit 62 during the driving period.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load power supply voltage monitoring device preferably used in a so-called antilock brake system or the like for preventing wheels from becoming locked.

[0002]

2. Description of the Related Art When a brake is suddenly applied on a wet road surface or a snowy road, the wheels stop rotating and reach a locked state. When the wheels are locked in this way, not only the braking distance increases, but also the lateral grip force of the tire (hereinafter referred to as "cornering force") is lost and steering becomes impossible, resulting in an extremely dangerous condition. Become. In addition, the loss of cornering force can cause the vehicle to become unstable, causing it to sway and spin.

Therefore, conventionally, in order to prevent the wheels from being locked even when the brake pedal is strongly depressed to perform a sudden braking operation, a so-called anti-lock
A braking system (hereinafter referred to as "ABS") is installed in a vehicle and used. The ABS detects the vehicle speed, which is the actual vehicle speed, and the wheel speed, which is the vehicle speed corresponding to the rotation of the wheels, and the slip ratio defined by the following equation (1) is set to a predetermined value. The brake pressure of each wheel is controlled so as to approach the control target value.

[0004]

[Equation 1]

That is, the coefficient of friction between the tire and the road surface becomes maximum not when the slip ratio is 100% (completely locked state where the wheel speed is 0), but when the slip ratio is 2.
It is known to be around 0%. On the other hand, the cornering force decreases as the slip ratio increases,
It becomes 0 at 100%. Therefore, in the ABS, the brake pressure is controlled at the time of the sudden braking operation so that the slip ratio is around 20% so that the friction coefficient between the tire and the road surface becomes maximum.

[0006] By such anti-lock control, ideal braking that minimizes the braking distance and secures vehicle stability and steerability is realized regardless of the driving technique of the driver. The control of the brake pressure is performed by controlling the hydraulic pressure from the master cylinder connected to the brake pedal with the hydraulic pressure unit. The hydraulic unit is provided with solenoid valves corresponding to the front and rear wheels, and these solenoid valves are used as control units (EC
Driven by U), the hydraulic pressure transmitted to the brake of each wheel is controlled. Excess liquid resulting from the control of hydraulic pressure is returned to the master cylinder by the pump.

Electric power is supplied from the battery to the solenoid valve, but if the voltage applied to the solenoid valve is lowered due to a drop in battery voltage or the like, the solenoid valve cannot be driven well.
As a result, the control of the brake pressure of each wheel becomes poor, and it is dangerous to perform the antilock control in such a state. Therefore, conventionally, the voltage applied to the solenoid valve is monitored, and when a decrease in the applied voltage is detected, the antilock control is stopped, and the warning lamp provided on the instrument panel is turned on to turn off the ABS. The driver is notified that the vehicle is in an operating state.

A prior art technique for monitoring the applied voltage to a solenoid valve is shown in FIG. The battery voltage V _B from the battery 1 mounted on the vehicle is passed through the harness as the ignition voltage V _IG to the control unit (EC
U) 2 and the stabilized power supply circuit 3 supplies a power supply voltage Vcc (5
V) is created. The voltage V _IG is also _supplied to the power supply voltage monitoring circuit 5. The power supply voltage monitoring circuit 5 gives a predetermined detection output to the microcomputer 4 when detecting that the voltage V _IG has become lower than a predetermined voltage (for example, 10 V).

The battery voltage V _B is also applied to the above warning lamp 6 for notifying the driver that the ABS is inactive, and also via line 7 a solenoid valve in the hydraulic unit. 8 is also supplied. An output transistor 10 for driving the solenoid valve 8 is connected to the microcomputer 4. The collector voltage of the transistor 10 is
The voltage is divided by 12, and the voltage at the voltage dividing point 13 is connected to the input port P1 of the microcomputer 4. The microcomputer 4 monitors the drive state of the solenoid valve 8 by monitoring the signal from the input port P1.

Further, the electric power from the battery 1 is supplied via the relay 19 to the motor 14 for driving the pump for returning the excess liquid generated as a result of the hydraulic pressure control to the master cylinder. . The relay 19 is controlled by the microcomputer 4 to be conductive / interrupted. As for the operating state of the motor 14, the potential between the motor 14 and the relay 19 is monitored by a monitor circuit 20 including an analog / digital converter and the like.
This is achieved by inputting the output of 0 to the input port P2 of the microcomputer 4. The microcomputer 4 determines whether the operation of the motor drive system including the relay 19 and the motor 14 is normal, depending on the magnitude of the input data.

When the voltage V _IG becomes less than the predetermined voltage in the power supply voltage monitoring circuit 5, a signal indicating this is given from the power supply voltage monitoring circuit 5 to the microcomputer 4. In response to this, the microcomputer 4 turns on the warning lamp 6 and at the same time prohibits the antilock control. As a result, when the battery voltage V _B is lowered to such an extent that the solenoid valve 8 may be driven poorly, the antilock control is prohibited, so that it is possible to prevent a malfunction in the braking operation.

However, in this prior art, the voltage applied to the solenoid valve 8 is not directly detected, but only the ignition voltage V _IG is detected. That is, what is applied to the solenoid valve 8 is the voltage that has passed through the line 7, and this line 7 is composed of a harness, but since this harness is different from the harness that supplies the ignition voltage V _IG , The voltage V _IG monitored by the power supply voltage monitoring circuit 5 may be different from the voltage applied to the solenoid valve 8. Therefore, in the above-described prior art in which the voltage applied to the solenoid valve 8 cannot be accurately monitored, there is a possibility that the antilock control cannot be reliably prohibited when the voltage applied to the solenoid valve 8 decreases. is there.

Another prior art for solving this problem is shown in FIG. 6, parts corresponding to the respective parts shown in FIG. 5 are designated by the same reference numerals. Further, in FIG. 6, illustration of the configuration related to the motor 14 in FIG. 5 is omitted. In this prior art, the voltage applied to the solenoid valve 8 is directly detected by monitoring the voltage at the line 7 side terminal of the solenoid valve 8. That is, the voltage applied to the solenoid valve 8 is input to the control unit 2 from the line 15. This voltage is divided by resistors 16 and 17 and input to the analog / digital conversion input port A / D of the microcomputer 4.

With this configuration, the microcomputer 4
Then, the drop of the applied voltage is detected by monitoring the input voltage to the input port A / D. The operation after this is
This is similar to the case of the first prior art described above.

[0015]

However, in the second prior art, since a new wiring corresponding to the line 15 is required, there is a problem that the structure is complicated and the cost is increased. is there. In order to solve this problem, the applicant of the present application filed Japanese Patent Application No. 3-296983 previously filed.
5 proposes a technique for improving the first prior art shown in FIG. 5 to apply the potential of the connection point 13 to an analog / digital (A / D) conversion input port provided in the microcomputer 4. . In the technology related to this proposal,
Output transistor 10 is cut off and solenoid valve 8
When no current flows through the output transistor 10
The collector potential of is equal to the voltage applied to the solenoid valve 8, and the voltage corresponding to this applied voltage is applied to the microcomputer 4 from the connection point 13. That is, the microcomputer 4 monitors the voltage applied to the solenoid valve 8 by monitoring the input voltage of the A / D conversion input port during the off period of the output transistor 10.

For example, a hydraulic unit is installed in front of and behind the vehicle.
In the case of a four-channel configuration having four sonoid valves corresponding to each wheel, an output transistor 10 and a voltage dividing circuit composed of resistors 11 and 12 are provided for each solenoid valve, and each voltage dividing circuit has a voltage dividing circuit. The potentials at the voltage dividing points are input to the A / D conversion input ports of the microcomputer 4, respectively.

In the structure of the proposed example, not only the applied voltage of the solenoid valve 8 can be directly detected, but also monitoring of the applied voltage is achieved by using the existing voltage dividing circuits 11 and 12, so that a new harness is provided. There is an advantage that the configuration is not required and therefore the configuration is not complicated. However, in this proposed example, the applied voltage cannot be detected while the solenoid valve 8 is being driven, and even in the case of the 4-channel configuration, the applied voltage cannot be monitored while all the solenoid valves are being driven. There's a problem. Therefore, if the applied voltage drops during the driving period of the solenoid valve 8,
This cannot be detected promptly, and antilock control cannot be prohibited immediately.

Therefore, an object of the present invention is to solve the above-mentioned technical problems and to provide an accurate applied voltage to a load with a simple structure.
It is an object of the present invention to provide a load power supply voltage monitoring device capable of monitoring even during a load driving period.

[0019]

According to a first aspect of the present invention, there is provided a load power supply voltage monitoring apparatus, wherein a power supply having a constant potential with respect to a ground potential and an electric power from the power supply are provided. A first load to be supplied, first switching means connected in series between the first load and the ground potential, and controlling the supply of electric power to the first load, and the first load. First monitoring means for monitoring a voltage between a load and the first switching means and outputting a signal corresponding to the voltage, and a second monitoring means connected to the power source in parallel with the first load. Load, and second switching means connected in series between the second load and the power source and controlling the supply of electric power to the second load in cooperation with the first switching means. Between the second switching means and the second load Second monitoring means for monitoring the pressure and outputting a signal corresponding to this voltage, and the respective output signals of the first monitoring means and the second monitoring means are given to drive the first load. It is determined whether or not the voltage applied to the first load is normal based on the output signal of the first monitoring means during the period when the first load is not operating, and the first voltage is applied during the period when the first load is being driven. And a determination unit that determines whether or not the voltage applied to the first load is normal based on the output signal of the second monitoring unit.

According to the above arrangement, the first switching means is connected in series between the first load and the ground potential, so that if the first load is in the non-driving state, the first The voltage between the first load and the first switching means monitored by the monitoring means becomes equal to the voltage applied to the first load. On the other hand, the second switching means is connected between the second load connected in parallel with the first load and the power supply. The second switching means is interlocked with the first switching means, and when the first switching means is conducting, the second switching means is also conducting. Therefore, the voltage between the second switching means and the second load, which is monitored by the second monitoring means, varies between the first load and the second switching means when the first load is in the driving state. It is equal to the voltage supplied in common. That is, the monitoring voltage of the second monitoring means during the driving period of the first load is equal to the voltage applied to the first load.

Therefore, in monitoring the applied voltage of the first load, the determining means refers to the output of the first monitoring means during the non-driving period of the first load, and during the driving period of the first load. Refers to the output of the second monitoring means.
This makes it possible to accurately monitor the voltage applied to the first load during both the driving period and the non-driving period of the first load.

Moreover, if an existing monitor circuit for monitoring the drive state of the second load is used as the second monitoring means, the device is constructed without using extra circuits and wiring. You can also In addition, when a plurality of series circuits of the first load and the first switching means are connected in parallel to the power supply, the first monitoring means is connected to each of the first loads. When the determination means is not driving at least one of the plurality of first loads, the determination means is based on the output signal of the first monitoring means corresponding to the first load in the non-driving state. First of the above
Whether or not the applied voltage to the load is normal, the second load is applied during a period in which all of the plurality of first loads are driven.
It is only necessary to determine whether or not the voltage applied to the plurality of first loads is normal based on the output signal of the monitoring means.

When a plurality of circuits of the first load and the first switching means are connected in parallel to the power supply, the first monitoring means corresponds to each first load. Is provided, and whether the voltage applied to the plurality of first loads is normal based on the output signal of the first monitoring unit while the determination unit is not driving all of the plurality of first loads. Whether at least one of the plurality of first loads is being driven, the voltage applied to the plurality of first loads is determined based on the output signal of the second monitoring means. It may be possible to determine whether or not it is normal.

[0024]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 2 is a conceptual diagram showing an outline of an antilock brake system (hereinafter referred to as “ABS”) to which a load power supply voltage monitoring device according to an embodiment of the present invention is applied. ABS is a wheel speed sensor 2 provided on each wheel.
This is a device that electronically controls the brake pressure of the brake 22 of each wheel based on the output of No. 1 to avoid locking of the wheel during a sudden braking operation and realizes an optimum slip ratio. That is, when the brake pedal 23 is strongly depressed, the hydraulic pressure from the master cylinder 24 is controlled by the hydraulic unit 25 and is transmitted to the brake 22 of each wheel. The hydraulic unit 25 is provided with, for example, four channels for individually controlling the hydraulic pressure for each wheel, and at least one solenoid valve for controlling the hydraulic pressure is provided for each channel. It is provided. The drive control of the solenoid valve is performed by the control unit (ECU) 26 that monitors the output of the wheel speed sensor 21. Reference numeral 27 is a warning lamp for notifying the driver of the possibility that the control thereof may become defective due to the reduction of the voltage applied to the solenoid valve and therefore the antilock control is prohibited. .

FIG. 1 is a block diagram showing the electrical construction related to the driving of the solenoid valve. The electric power from the battery 31 (for example, the rated output voltage is 12 V) is supplied to the control unit 26 via the ignition switch 32, and at the same time, the relay of the relay 34 that controls the power supply to the solenoid valve 33 in the hydraulic unit 25. It is provided to the coil 34b. Relay 34 switches the electric power from battery 31 applied via line 35 to line 36. In addition, the electric power via the ignition switch 32 is given to the warning lamp 27.

Further, the electric power from the battery 31 is supplied from the line 35 through the contact 39a of the relay 39 to the motor 40 in the hydraulic unit 25. The motor 40 drives a pump (not shown) that returns excess liquid generated in the hydraulic unit 25 to the master cylinder 24 for controlling the hydraulic pressure. The relay coil 39b of the relay 39 is supplied with power from the battery 31 via the contact 34a of the relay 34. Relay 3
9 and the operating state of the motor 40 are monitored in the control unit 26 via the line 47.

Reference numeral 41 is a stop lamp which is turned on by being supplied with electric power through a switch 42 which is turned on by operating the brake pedal 23. The operation state of the brake pedal 23 is monitored by the control unit 26 via the line 43. The warning lamp 27 is turned on when the control unit 26 grounds the line 44. When the contact 34a of the relay 34 is connected to the ground side, a current flows from the line 45 through the diode 46, and the warning lamp is turned on at this time as well. The control unit 26 includes the ignition switch 3
In the period immediately after 2 becomes conductive, the relay coil 3
4b is demagnetized, the contact 34a is connected to the ground side, and the warning lamp 27 is turned on. Then, the relay coil 34b is excited. This allows the solenoid valve 3
3 and the relay coil 39b can be supplied with electric power. When the signal ALT-L indicating this is given when power generation by a generator (not shown) is started, the warning lamp 27 is turned off.

The control unit 26 has a microcomputer 51 functioning as a judging means inside, and an output transistor 52 which is a first switching means for driving the solenoid valve 33 which is a first load. . This transistor 52 and solenoid valve 33
And ground potential are connected in series. The operating voltage Vcc to the microcomputer 51 is the stabilized power supply circuit 5
Created in 5. The microcomputer 51 turns on / off the transistor 52 so that the solenoid valve 3
Excitation / demagnetization of 3 The output transistor 52 and the circuit related thereto are provided individually for each solenoid valve 33, but in FIG. 1, only the circuit configuration for one channel is shown, and the solenoids corresponding to other channels are shown. Illustration of a circuit configuration related to the valve 33 is omitted.

The collector voltage of the transistor 52 is the first
The potential that appears at the voltage dividing point 53 after being divided by the resistors R1 and R2 that form the monitoring circuit 61 is applied to the analog / digital conversion input port AD1 of the microcomputer 51. The collector of the transistor 52 has an analog / electrical element due to the back electromotive force generated in the solenoid valve 33.
A Zener diode 54 that prevents an overvoltage from being applied to the digital conversion input port AD1 is connected.

The resistors R1 and R2 are arranged so that the potential at the voltage dividing point 53 is equal to or lower than the voltage Vcc (for example, 5 V) which is the reference voltage for analog / digital conversion even when the collector voltage of the transistor 52 is maximum. The resistance value is set. In addition, the first corresponding to other channels
The outputs of the circuits similar to the monitoring circuit 61 are A / D conversion input ports AD2 to AD of the microcomputer 51, respectively.
Is given to 4.

On the other hand, a second monitoring circuit 62 for monitoring the voltage from the line 47 is further provided in the control unit 26. The second monitoring circuit 62 is composed of an A / D converter and the like, and inputs the data corresponding to the voltage derived on the line 47 to the input port P of the microcomputer 51. When the solenoid valve 33 is driven to control the hydraulic pressure, the relay 39 serving as the second switching means is closed in conjunction with this, and the motor 40 serving as the second load is energized. A pump (not shown) for returning the excess liquid generated as a result of the hydraulic pressure control to the master cylinder 24 is activated. The voltage on line 47 when relay 39 is closed is equal to the voltage applied to solenoid valve 33 via relay 34.

FIG. 3 is a flow chart for explaining the operation of the microcomputer 51 related to the monitoring of the voltage applied to the solenoid valve 33. In step S1, the input values of the A / D conversion input ports AD1 to AD4 are referred to, and it is checked whether or not all the four-channel solenoid valves 33 are in a driven state. That is, when the output transistor 52 becomes conductive, the potential of the connection point 53 of the first monitoring circuit 61 decreases, so that the microcomputer 5
In No. 1, it is possible to detect whether or not the solenoid valve 33 is in a driving state by checking whether or not the input value is equal to or less than the predetermined value.

As a result of such processing, if it is determined that at least one solenoid valve 33 is in the non-driving state, the process proceeds to step S2. In step S2, the maximum value of the input values of the input ports AD1 to AD4 is selected, and this maximum value is used as the load power supply voltage data. That is, at least one solenoid valve 33
Is the non-driving state, the maximum value of the input values of the input ports AD1 to AD4 is the input value from the first monitoring circuit 61 corresponding to the non-driving solenoid valve 33. As described above, if the solenoid valve 33 is in the non-driven state,
The first corresponding to this non-driven solenoid valve 33
Since the output of the monitoring circuit 61 corresponds to the voltage applied to the solenoid valve 33 (that is, the load power supply voltage), the maximum value of the input values of the input ports AD1 to AD4 eventually corresponds to the load power supply voltage.

When it is determined in step S1 that all the solenoid valves 33 are driven, the process proceeds to step S3. In step S3, the input value from the input port P is referred to, and the input value of the input port P is set as the load power supply voltage data. As described above, when the solenoid valve 33 is driven to control the hydraulic pressure in the hydraulic unit 25, the relay 39 is closed and the motor 40 is driven, and the excess liquid is returned to the master cylinder 24. Therefore, when the solenoid valve 33 is driven, a voltage equal to the voltage applied to the solenoid valve 33 is derived from the line 47 downstream of the relay 39 with respect to the battery 31 that is the power source. Therefore, the solenoid valve 33
The voltage applied to the solenoid valve 33 can be known by monitoring the voltage of the line 47 during the driving of.

The process in step S3 has such significance, and the solenoid valve 33 is read by reading the data corresponding to the voltage derived on the line 47 from the second monitoring circuit 62 via the input port P. The voltage applied to is detected. In step S4, the load power supply voltage data is compared with the predetermined value V1. If the load power supply voltage data is less than the predetermined value V1, the microcomputer 51 turns on the warning lamp 27 in step S5 and prohibits the antilock control in step S6. When the load power supply voltage data is equal to or higher than the predetermined value V1, it is determined that the voltage applied to the solenoid valve 33 is sufficiently high, and the process returns to step S1. In addition,
The predetermined value V1 corresponds to the potential of the voltage dividing point 53 corresponding to the minimum value of the applied voltage required to drive the solenoid valve 33. Specifically, it is set to a value corresponding to the voltage (for example, 1V) of voltage dividing point 53 when the collector voltage of transistor 52 is, for example, 10V.

As described above, according to this embodiment, when all the solenoid valves 33 are in the driving state, the voltage drawn to the line 47 is monitored,
The voltage applied to the solenoid valve 33 can be monitored. As a result, even if all the solenoid valves 33 are in a driving state, the voltage applied to the solenoid valves 33 can be monitored. Therefore, the voltage applied to the solenoid valves 33 can be directly measured over the entire period of the antilock control. It will be possible to detect. As a result, even during the driving period of the solenoid valve 33,
Even if the voltage applied to the solenoid valve 33 is lowered, this can be surely detected and the antilock control can be immediately prohibited. As a result, the safety of ABS can be further improved.

Moreover, as shown in FIG. 5, the structure for monitoring the operation of the motor driving the pump for reducing the excess liquid generated in the hydraulic unit has been conventionally provided. The present embodiment has a great feature in that the monitoring of the voltage applied to the solenoid valve 33 during the driving period of the solenoid valve 33 is achieved by utilizing such an existing configuration. In such a configuration, FIG.
Since no new wiring is required unlike the prior art, the structure is not complicated and the cost is not increased.

FIG. 4 is a flow chart for explaining the operation of another embodiment of the present invention. In this FIG.
Steps in which the same processes as those of the steps shown in FIG. 5 are performed are designated by the same reference numerals. In the present embodiment, in step S10, it is determined whether or not at least one of the 4-channel solenoid valves 33 is driven. When at least one channel solenoid valve 33 is driven, step S3
Then, the value from the input port P is substituted into the load power supply voltage data. Also, which channel solenoid valve 3
When 3 is also not driven, the maximum value of the input values from the A / D conversion input ports AD1 to AD4 is set as the load power supply voltage data in step S2. Subsequent processing is the same as in the case of the above embodiment.

As described above, the present embodiment is characterized in that when at least one solenoid valve 33 is driven, the voltage from the motor drive system is referred to via the line 47. In the present embodiment, instead of the processing in step S2, the average value of the input values of the input ports AD1 to AD4 may be used as the load power supply voltage data. That is, in this embodiment, the input ports AD1 to AD
Since the input to No. 4 is referred to when the solenoid valve 33 of any channel is not driven, the input values of the input ports AD1 to AD4 at this time all correspond to the voltage applied to the solenoid valve 33. ing. Therefore, by taking the average of these, the voltage applied to the solenoid valve 33 can be detected more accurately.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the second monitor circuit 62 is composed of an A / D converter or the like, but the second monitor circuit 62 may be composed of a comparator. That is, the voltage of the line 47 may be level-discriminated by a certain threshold voltage, and the signal "0" or "1" may be input to the microcomputer 51 as a comparison result. In this case, if the threshold voltage is set to the minimum applied voltage required to drive the solenoid valve 33, the microcomputer 51 immediately determines whether the applied voltage is sufficient based on the comparison result. Can be determined.

Further, in the above-mentioned embodiment, the configuration in which the plurality of solenoid valves as the first load are provided has been described, but it goes without saying that the first load may be one. Further, in the above-described embodiment, the case of being used for ABS is taken as an example, but the load power supply voltage monitoring device of the present invention may directly monitor the voltage applied to the load in addition to ABS. It can be widely applied to. Further, it goes without saying that it can be applied to any load other than the solenoid. In addition, various design changes can be made without changing the gist of the present invention.

[0042]

As described above, according to the load power supply voltage monitoring apparatus of the present invention, during the period when the first load is driven and the load power supply voltage cannot be monitored by the first monitoring means,
The load power supply voltage is monitored by the second monitoring means provided in association with the second switching means that supplies power to the second load in conjunction with the first switching means. As a result, it is possible to favorably monitor whether the load power supply voltage is normal in any period.

Moreover, the second monitoring means for monitoring the voltage between the second load and the second switching means includes the second
An existing monitor circuit or the like for monitoring the drive state of the load may be used as it is, and thus an extra circuit or wiring is not required. As a result, the configuration can be simplified and an increase in cost can be suppressed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an antilock brake system to which a load power supply voltage monitoring device according to an embodiment of the present invention is applied.

FIG. 2 is a conceptual diagram showing an outline of an antilock brake system.

FIG. 3 is a flowchart for explaining a process relating to monitoring of a voltage applied to a solenoid valve in a microcomputer.

FIG. 4 is a flow chart for explaining processing in another embodiment of the present invention.

FIG. 5 is a block diagram showing an electrical configuration of a prior art.

FIG. 6 is a block diagram showing an electrical configuration of another prior art.

[Explanation of symbols]

 25 hydraulic unit 26 control unit 31 battery (power source) 33 solenoid valve (first load) 39 relay (second switching means) 40 motor (second load) 51 microcomputer (determination means) 52 output transistor (first) 1 switching means) 53 voltage dividing point 61 first monitoring circuit 62 second monitoring circuit

Claims (3)

[Claims] 1. A power source having a constant potential with respect to a ground potential, a first load supplied with power from the power source, and connected in series between the first load and the ground potential, The voltage between the first switching means that controls the supply of electric power to the first load and the first load and the first switching means is monitored, and a signal corresponding to this voltage is output. First monitoring means, a second load connected to the power source in parallel with the first load, a second load connected in series between the second load and the power source, and the first switching Second switching means for controlling the supply of electric power to the second load in cooperation with the means, and monitoring the voltage between the second switching means and the second load to respond to this voltage Second monitoring means for outputting a signal for And each output signal of the second monitoring means is applied, and the voltage applied to the first load is normal based on the output signal of the first monitoring means while the first load is not driven. It is determined whether or not the voltage applied to the first load is normal based on the output signal of the second monitoring means while the first load is being driven. And a load power supply voltage monitoring device. 2. A power source having a constant potential with respect to the ground potential, a plurality of first loads connected in parallel to the power source, and a series connection between each first load and the ground potential. A plurality of first switching means that are connected to each other and individually control the supply of electric power to each first load; and a plurality of first switching means that are provided corresponding to each first load. A plurality of first monitoring means for respectively monitoring the voltage between the means and outputting a signal corresponding to the voltage, and a second load connected to the power source in parallel with the first load, Second switching means connected in series between the second load and the power source and controlling the supply of electric power to the second load in cooperation with the first switching means; and the second switching means. By monitoring the voltage between the switching means and the second load, Second monitoring means for outputting a corresponding signal, and respective output signals of the plurality of first monitoring means and the second monitoring means are provided to drive at least one of the plurality of first loads. In the non-driving period, it is determined whether or not the voltage applied to the plurality of first loads is normal based on the output signal of the first monitoring means corresponding to the first load in the non-driving state, Judgment means for judging whether or not the voltage applied to the plurality of first loads is normal based on the output signal of the second monitoring means while all of the plurality of first loads are being driven. A load power supply voltage monitoring device comprising: 3. A power source having a constant potential with respect to the ground potential, a plurality of first loads connected in parallel to the power source, and a series connection between each first load and the ground potential. A plurality of first switching means that are connected to each other and individually control the supply of electric power to each first load; and a plurality of first switching means that are provided corresponding to each first load. A plurality of first monitoring means for respectively monitoring the voltage between the means and outputting a signal corresponding to the voltage, and a second load connected to the power source in parallel with the first load, Second switching means connected in series between the second load and the power source, and controlling the supply of electric power to the second load in cooperation with the first switching means; and the second switching means. By monitoring the voltage between the switching means and the second load, A period in which the second monitoring means that outputs a corresponding signal and the output signals of the plurality of first monitoring means and the second monitoring means are given and all of the plurality of first loads are not driven. It is determined whether the applied voltage to the plurality of first loads is normal based on the output signal of the first monitoring means, and at least one of the plurality of first loads is driven. The load power supply voltage monitoring device characterized in that the period during which the load power supply voltage monitoring device includes a determination unit that determines whether or not the voltage applied to the plurality of first loads is normal based on the output signal of the second monitoring unit. .