JP2002023869A - Current conduction controller for inductive load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control load currents even when a power supply voltage fluctuates while ensuring current control precision in a device for controlling the currents of an inductive load by duty ratio. SOLUTION: A controlling duty ratio is calculated so that load current (i) can be turned to target current by a control circuit 10, and a switching element Tr0 arranged on a conducting path to a linear solenoid L0 is driven by duty ratio according to the controlling duty ratio. A load resistance switching circuit 20 capable of switching voltage drop quantity (resistance value) is arranged on the conducting path to the linear solenoid L0, and the resistance value of the load resistance switching circuit 20 is controlled so that the voltage drop quantity can be increased according as the controlling duty ratio is made larger (or a power supply voltage +B is made higher). Thus, it is possible to prevent a voltage to be applied to the linear solenoid L0 from being largely changed according as the power supply voltage +B fluctuates, and to increase a current controllable power supply voltage range without decreasing the resolution of the current control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductive load energization control device for controlling a current flowing through an inductive load such as a linear solenoid to a target current.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for controlling a current (load current) flowing through an inductive load to a target current, for example,
As described in Japanese Patent Publication No. 4-500399, a device for controlling a load current by switching a voltage applied to a load using a switching element, for example, Japanese Patent Application Laid-Open No.
As described in Japanese Patent Publication No. 229576, a switching element provided on an energization path from a DC power supply to an inductive load is duty-driven by a duty-controlled drive signal (a so-called PWM (pulse width modulation) signal). Devices for controlling current are known.

[0003] In the former device, the voltage applied to the inductive load (and, consequently, the load current) can only be changed stepwise, and the current value is large when the applied voltage is switched. There is a problem that it changes. In addition, when the inductive load is a linear solenoid, in the former device, when a desired current flows through the solenoid by controlling the applied voltage and the movable part is controlled to a predetermined position, the movable part stops, so Even if the voltage applied to the solenoid is changed to change the position of the movable part, the linear solenoid may not respond due to the static friction coefficient generated in the movable part.

On the other hand, in an apparatus for duty-controlling a load current by duty-driving a switching element as in the latter, it is possible to continuously change the load current by adjusting the duty ratio of a drive signal. As a result, the load current can be controlled to a desired current. Also, since the load current constantly fluctuates around the target current due to the switching operation of the switching element, when the inductive load is a linear solenoid, the dynamic friction coefficient always acts on the movable part. ,
The movable part can always be controlled to a desired position.

For this reason, conventionally, when controlling the energization of an inductive load, such as a linear solenoid, which needs to control the movable part to an arbitrary position, the energization from the DC power supply to the inductive load is performed as in the latter case. A device for duty-driving a switching element provided on a path is used.

By the way, in this kind of energization control device, when a DC power supply whose output voltage (power supply voltage) tends to fluctuate, such as an in-vehicle battery, the power supply voltage is reduced from the normal voltage. However, in order to allow a desired current to flow through the inductive load, the drive duty ratio of the switching element for flowing the maximum current when the power supply voltage is the normal voltage is generally set low.

Specifically, for example, in an automobile having a normal power supply voltage (battery voltage) of 14 V, the power supply voltage is reduced to 8 V, which is a voltage value at which an electronic control device for controlling an engine or the like can operate. In order to allow a desired current to flow through an inductive load such as a linear solenoid constituting various actuators, as shown in FIG. Is about 50%, and the load current is set to the maximum current value (1 A in the figure).

In this case, as shown in FIG. 10, even if the power supply voltage + B drops to around 8 V, the load current is controlled to be near the maximum current by increasing the drive duty ratio up to 100%. It is possible to do. In this case, as shown in FIG. 10, even if the power supply voltage + B rises from the normal state, the load current can be controlled to a desired current by making the drive duty ratio smaller than the normal state.

[0009]

However, if the normal driving duty ratio is set to be about 50% at the maximum as described above, the normal current resolution controllable by the duty control is reduced, and the load is reduced. There is a problem that current control accuracy is reduced.

That is, for example, if the load current is proportional to the drive duty ratio, the resolution of the duty ratio capable of controlling the drive signal is 0.1%, and the maximum current value of the load current to be controlled is 1A. , Drive duty ratio 100%
When the maximum current value can be realized in the vicinity, the resolution of the controllable load current is 1 mA (= 1 A / (100
/0.1)), as described above, if the normal duty ratio is set to about 50% at the maximum current value, the controllable load current resolution is 2 mA (1 A / (5
0 / 0.1)), which reduces the control accuracy of the load current.

In recent years, it has been considered that the power supply voltage of a battery (DC power supply) mounted on an automobile is set to 42 V.
In order to normally control the energization of an inductive load such as a linear solenoid within the voltage range (8 to 42 V) until the voltage drops to V, it is impossible with the above conventional measures. There was also.

That is, in such a system, if the drive duty ratio for flowing the maximum current (1 A) at the normal power supply voltage (42 V) is set to 50%, the maximum current when the power supply voltage drops to 8 V is set. , The drive duty ratio must be greater than 100%,
It becomes impossible to control. When the power supply voltage is 8 V, the maximum current (1 A) is obtained at a drive duty ratio of about 100%.
Power supply voltage (42V) during normal operation
And the drive duty ratio for flowing the maximum current (1A) is 2
It must be set to 0% or less (= 8/42), which makes it impossible to normally control the load current satisfactorily.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and in a device for duty-controlling a current flowing through an inductive load, it is possible to ensure the control accuracy of the load current without being affected by the fluctuation of the power supply voltage. An object is to enable control of a load current.

[0014]

According to a first aspect of the present invention, there is provided an inductive load energization control device, wherein current detecting means detects a load current flowing through the inductive load. The duty ratio calculating means calculates a control duty ratio necessary for controlling the load current to the target current based on the detected load current and the target current, and the driving means calculates a control duty ratio according to the calculated control duty ratio. Then, the switching element provided on the current path from the DC power supply to the inductive load is turned ON / OFF.

In addition, on the current path from the DC power supply to the inductive load, a voltage applied from the DC power supply to the inductive load when the switching element is turned on (applied voltage), separately from the switching element for controlling the load current. ) Is provided, and the voltage drop adjusting means determines that the smaller the control duty ratio is, the larger the voltage drop amount by the voltage drop means becomes in accordance with the control duty ratio calculated by the duty ratio calculating means. Adjust the voltage drop means so that

As a result, according to the energization control device of the present invention (claim 1), when the control duty ratio calculated by the duty ratio calculation means increases due to the decrease in the power supply voltage, the voltage drop means The voltage drop amount is set to be small, the applied voltage to the inductive load increases,
Conversely, when the control duty ratio decreases due to an increase in the power supply voltage, the amount of voltage drop by the voltage drop means is set to increase, and the voltage applied to the inductive load decreases.

That is, in the present invention, the voltage applied to the inductive load is adjusted by adjusting the amount of voltage drop by the voltage drop means in accordance with the change in the control duty ratio caused by the change in the power supply voltage. It suppresses a large change according to. Therefore, according to the present invention, even if the power supply voltage fluctuates, it is not necessary to largely change the duty ratio when driving the switching element for current control, and the load current can be controlled with a stable resolution. . Therefore, according to the present invention, not only can the load current be controlled without being affected by the fluctuation of the power supply voltage, but also the resolution of the controllable load current can be prevented from greatly fluctuating with the fluctuation of the power supply voltage. The current control accuracy can be improved.

Here, in the energization control device according to the first aspect, the voltage applied to the inductive load does not fluctuate greatly even if the power supply voltage changes, so that the voltage is controlled according to the control duty ratio. The voltage drop by the dropping means is adjusted. However, the control duty ratio changes according to the fluctuation of the power supply voltage if the target current to be passed to the inductive load is constant, but also changes according to the fluctuation of the target current. For this reason, according to the energization control device of the first aspect, it is conceivable that the amount of voltage drop by the voltage drop means is adjusted when the target current changes, even though the power supply voltage is constant. .

In order to prevent such a problem,
According to a second aspect of the present invention, the power supply control device according to the first aspect further includes a power supply voltage detecting unit that detects a power supply voltage of the DC power supply, and the voltage drop adjusting unit includes a power supply voltage detecting unit. In accordance with the detected power supply voltage, the voltage drop means may be adjusted such that the higher the power supply voltage, the larger the voltage drop by the voltage drop means. In other words, with this configuration, it is possible to adjust the amount of voltage drop by the voltage drop unit only in response to the change in the power supply voltage without being affected by the change in the target current.

On the other hand, in the energization control device according to the first and second aspects, the voltage drop means is for adjusting the voltage applied to the inductive load when the switching element is turned on. It is necessary to make its own voltage drop variable. For this purpose, for example, as set forth in claim 3, the voltage drop means is constituted by a resistor connected in series to a current supply path to the inductive load, and a switch means connected in parallel to the resistor. The voltage drop adjusting means may adjust the amount of voltage drop by the voltage drop means (in other words, the voltage applied to the inductive load) by switching the ON / OFF state of the switch means.

That is, in this way, by turning on / off the switch means, the voltage drop means is determined by the state where the voltage drop amount is substantially zero and the voltage drop amount is determined by the resistance value of the resistor and the load current. It is possible to switch the power supply voltage to an intermediate voltage (for example, 11 V) in a system in which the power supply voltage is normally 14 V and the minimum guaranteed voltage is 8 V as described above. If this is the case, the switch means is turned off, and if the power supply voltage is lower than the intermediate voltage, the switch means is turned on, thereby controlling the load current within the voltage range of the power supply voltage of 8 to 14 V while ensuring control accuracy. Becomes possible.

Further, in order to further improve the control accuracy within the fluctuation range of the power supply voltage, the voltage drop means can be connected in series to the energizing path and the resistance values are mutually different. It is preferable that the voltage drop adjusting means is constituted by a plurality of different resistors, and that the voltage drop adjusting means adjusts the amount of voltage drop by the voltage dropping means by switching a resistor connected in series to the current path.

In other words, if the voltage drop means is constituted by a plurality of resistors and one of the resistors is selectively connected in series to the current path, the fluctuation of the voltage applied to the inductive load can be further reduced. Thus, the control accuracy of the load current can be improved. When the resistance value of the voltage drop means provided on the current supply path to the inductive load is switched in a stepwise manner as described in claim 3 or 4, the drive means is connected to the duty ratio calculation means. ON / OFF of the switching element using the control duty ratio calculated as it is
If this is done, the load current will suddenly change immediately after the switching of the resistance value of the voltage drop means.

Even if the load current suddenly changes in this manner, the load current converges to the target current by the subsequent current feedback. Therefore, the load current cannot be controlled to the target current. May malfunction. Therefore, in order to prevent such a sudden change in the load current due to the switching of the resistance of the voltage dropping means, the driving means may be configured as described in claim 5.

That is, in the energization control device according to the fifth aspect, the driving means operates according to the operation of the voltage drop adjusting means.
By setting the drive duty ratio for actually turning on and off the switching element from the control duty ratio calculated by the duty ratio calculation means, the load current flowing through the inductive load due to the resistance switching operation by the voltage drop adjustment means is reduced. Prevent sudden changes. Therefore, according to the power supply control device of the fifth aspect, in the device of the third or fourth aspect, a change in the load current that occurs when the resistance value of the voltage drop means is switched is suppressed, and the load current is reduced. It is possible to always stably control the target current.

In order to prevent such a sudden change in the load current, the voltage drop means is constituted by a variable resistor capable of continuously adjusting the resistance value, and the voltage drop adjustment means is provided. Alternatively, the resistance value of the variable resistor may be changed according to the power supply voltage. So if you do this,
Since the resistance value of the voltage drop means changes continuously according to the fluctuation of the power supply voltage, the load current does not suddenly change due to the change in the resistance value, and the load current can be stably controlled to the target current. it can.

In this case, if the load current (target current) is constant, the voltage applied to the inductive load is always controlled to a constant voltage. The ratio (drive duty ratio) is always 0 to 10 without considering the power supply voltage.
An arbitrary value between 0% can be set, and the load current can always be controlled with maximum resolution and high accuracy.

On the other hand, in the energization control device according to the first to sixth aspects, voltage drop means is provided on the current path to the inductive load, and the amount of voltage drop by the voltage drop means is adjusted. Although the change of the applied voltage to the inductive load caused by the fluctuation of the power supply voltage is suppressed, in order to suppress the change of the applied voltage to the inductive load caused by the fluctuation of the power supply voltage as described above, It is not always necessary to provide a voltage drop unit for generating a voltage drop on the current path, and the current control device may be configured as described in claims 7 to 9.

That is, in the energization control device according to the seventh aspect, by using a DC voltage having a plurality of output terminals capable of outputting different DC voltages as the DC power supply, inductive power is supplied from each output terminal of the DC power supply. A plurality of current paths leading to a load are formed, and a switching element for current control is provided in each of the plurality of current paths. Then, the switching element selecting means operates the driving means in accordance with the control duty ratio calculated by the duty ratio calculating means such that the larger the control duty ratio, the higher the output voltage becomes the switching element on the output terminal side. The switching element used for control is selected, and the other switching elements are fixed in the OFF state.

As a result, when the control duty ratio calculated by the duty ratio calculation means increases due to the decrease in the power supply voltage, the output voltage of the DC power supply increases. An energizing path from the output terminal on the side to the inductive load is selected, and the switching element on the path is used for current control. Also,
Conversely, when the control duty ratio decreases due to an increase in the power supply voltage, an energizing path from the output terminal on the low output voltage side to the inductive load is selected in the DC power supply, and the switching element on that path causes a current to flow. Used for control.

For this reason, also in the energization control device according to the seventh aspect, it is possible to suppress the voltage applied to the inductive load from changing according to the fluctuation of the power supply voltage, and the power supply voltage is changed. Also, the load current can be accurately controlled to the target current. According to the power supply control device of the seventh aspect, it is necessary to provide a voltage drop means made of a resistor or the like on the power supply path to the inductive load as in the devices of the first to sixth aspects. Since there is no power consumption, unnecessary power consumption by the voltage drop unit can be eliminated, and the amount of power consumption by the power supply control device can be reduced.

On the other hand, the energization control device according to claim 8 is
The power supply control device according to claim 7, further comprising a power supply voltage detection unit that detects a power supply voltage output from at least one output terminal of the DC power supply, wherein the switching element selection unit includes a power supply voltage detection unit. In accordance with the detected power supply voltage, the switching element used by the driving means for control is selected such that the lower the power supply voltage is, the higher the output voltage becomes the switching element on the output terminal side, and the other switching elements are turned off. It is configured to be fixed to.

Therefore, according to the energization control device according to the eighth aspect, the same effect as the device according to the seventh aspect can be obtained, and the switching element used for control by directly detecting the fluctuation of the power supply voltage can be obtained. Since the selection can be made, it is possible to obtain the same effect as the above-described claim 2 that the selection can be made without being affected by the fluctuation of the target current.

Next, in the power supply control device according to the ninth aspect, the drive means actually switches the switching element from the control duty ratio calculated by the duty ratio calculation means in accordance with the operation of the switching element selection means. ON / OFF
By setting the drive duty ratio to be set, it is possible to prevent a sudden change in the load current flowing through the inductive load due to the switching element selecting operation by the switching element selecting means.

In this device, the driving means is configured to turn ON / OFF the switching element by using the control duty ratio calculated by the duty ratio calculation means as it is, in the device according to claim 7 or 8. Immediately after switching of the switching element used for control by the switching element selecting means, the load current may suddenly change suddenly, so that the load current is prevented from suddenly changing.

Therefore, according to the device of the ninth aspect, similarly to the device of the fifth aspect, the change in the load current that occurs immediately after the switching element selecting means switches the switching element used for control is suppressed. However, the load current can always be stably controlled to the target current.

[0037]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is an electric circuit diagram showing the configuration of an entire energization control device according to a first embodiment of the present invention.

The energization control device according to the present embodiment includes a linear solenoid L for displacing a movable portion (not shown) according to an energization current.
And a switching element Tr0 provided on a power supply path from a power supply line (power supply voltage + B) connected to the positive electrode side of a DC power supply (not shown) to the linear solenoid L0, and a linear solenoid L0. And a current detection resistor Rs provided on an energizing path from the power supply to the negative side of the DC power supply and a ground line having the same potential.

Further, between the switching element Tr0 and the linear solenoid L0, there is provided a load resistance switching circuit 20 composed of a parallel circuit of a resistor R0 and a switch SW0. This load resistance switching circuit 20 corresponds to the voltage drop means of the present invention (specifically, claim 3).
By turning on / off the switch SW0, it is possible to switch whether or not to cause a voltage drop due to the resistor R0 when energizing the linear solenoid L0.

The switching element Tr0 is composed of a PNP transistor whose emitter is connected to the power supply line and whose collector is connected to the load resistance switching circuit 20.
An SFET or the like can be used.

In this energization control device, the current detection resistor Rs
Is amplified by an amplifier circuit 4, and further amplified by an amplifier circuit 4.
Is passed through an integrating circuit 6 composed of a resistor Ra and a capacitor Ca to generate a current detection voltage from which a fluctuation component accompanying the switching operation of the switching element Tr0 has been removed. Is converted into digital data and input to the control circuit 10.

The control circuit 10 includes a CPU, a ROM, and a RAM.
A / D consisting of a microcomputer with a focus on
A current (load current) i actually flowing through the linear solenoid L0 is obtained from input data from the converter 8, a control duty ratio for controlling the load current i to a target current is set, and based on the control duty ratio, By controlling the duty of the switching element Tr0 via the drive circuit 2, the load current i is controlled to the target current.

Hereinafter, the energization control process executed by the control circuit 10 will be described. FIG. 2A is a flowchart illustrating the power supply control process. FIG.
As shown in (a), in the control circuit 10, first, S110
In step S, a target current to be passed through the linear solenoid L0 is calculated based on the operation state of a control target provided with the linear solenoid L0 as a control actuator. Based on the input data from the converter 8, the load current i actually flowing through the linear solenoid L0 is calculated.

In the present embodiment, the processing in S120 and the current detection resistor Rs, the amplifier circuit 4, the integration circuit 6, and the A / D converter 8 provided for detecting the load current are implemented in the present embodiment. It corresponds to the current detecting means of the invention. And the following S
At 130, a process as a duty ratio calculating means for calculating a control duty ratio “duty_OLG” for controlling the load current i to the target current based on the deviation between the calculated target current and the load current i is executed. In this calculation,
In order to quickly converge the load current i to the target current by the PID control, a well-known arithmetic expression including a proportional term, an integral term, and a derivative term for the deviation is used. In the present embodiment, the control duty ratio “duty
The maximum value of “_OLG” is set to be 200% which is twice the normal value.

When the control duty ratio "duty_OLG" is calculated in S130, the process proceeds to S140.
The calculated control duty ratio “duty_OLG” is 10
A set value smaller than 100% near 0% (for example, 90%)
%) Is determined.

If the control duty ratio "duty_OLG" is less than 90%, the switch SW0 is turned off in S150, so that the amount of voltage drop in the load resistance switching circuit 20 is reduced by the load current i and the resistance R0. In step S160, the switching element Tr0 is set to a value determined by the resistance value.
The control duty ratio “duty_OLG” is set as it is as the drive duty ratio “DUTY” for actually performing the duty drive, and the process proceeds to S190.

On the contrary, the control duty ratio “duty_OLG”
Is 90% or more, in S170, the switch SW0
Is turned on, the voltage drop amount in the load resistance switching circuit 20 is set to substantially 0, and in S180, the drive duty ratio “DUTY” for actually performing the duty drive of the switching element Tr0 is set as the control duty ratio. The value “duty_OLG / 2” is set to one half of the value, and the flow shifts to S190.

Then, in S190, S160 or S1
By outputting the drive duty ratio “DUTY” set at 80 to the drive circuit 2, the drive signal is subjected to a pulse width modulated drive signal (PWM signal) at the drive duty ratio “DUTY”. The switching element Tr0 is duty driven.

In this embodiment, the switch SW0 is turned ON / OFF according to the control duty ratio "duty_OLG".
The processing of S140, S150, and S170 for switching the state corresponds to the voltage drop adjusting means of the present invention (specifically, in claim 1), in order to set the drive duty ratio "DUTY" and perform the duty drive of the switching element Tr0. The processing of S160, S180, and S190 to be executed and the driving circuit 2 correspond to the driving unit of the present invention (specifically, claim 5).

As described above, according to the energization control device of this embodiment, if the control duty ratio "duty_OLG" calculated for controlling the load current i to the target current is less than 90%, the load resistance switching is performed. By generating a voltage drop due to the resistor R0 in the circuit 20, the voltage applied to the linear solenoid L0 is reduced, and conversely, the control duty ratio “duty
If "_OLG" is 90% or more, the voltage applied to the linear solenoid L0 is increased by setting the voltage drop amount by the load resistance switching circuit 20 to substantially zero.

The control duty ratio “duty_OLG” is
When the control duty ratio “duty_OLG” is set to be a maximum of 200% and the control duty ratio “duty_OLG” is less than 90%, the control duty ratio “duty_OLG” is directly used as the drive duty ratio “DUTY” for actually turning ON / OFF the switching element Tr0. Used, control duty ratio "duty_OLG" is 90%
In the above case, a value that is one half of the control duty ratio “duty_OLG” is used for the drive duty ratio “DUTY”.

For this reason, for example, the energization control device of this embodiment needs to supply a load current i of a maximum of 1 A at a normal power supply voltage + B of 14 V as in the energization control device for an automobile described above. When used in a system, the control duty ratio "duty_OL" for flowing the maximum current (1A) during normal operation
By setting an arithmetic expression for calculating the control duty ratio so that “G” becomes 70%, as shown in FIG. 3, even if the power supply voltage + B decreases to around 5 V, the load current i is reduced to 0 to 1A
Can be controlled without any problem within the range.

That is, in this case, while the load current i is controlled to 1 A, the power supply voltage + B is changed from 14 V to 10.9.
When the voltage drops to V, the control duty ratio “duty_OLG” increases to 90% due to the current feedback. At this time, the control circuit 10 sets the switch SW0
Is switched from OFF to ON, the voltage drop generated in the load resistance switching circuit 20 is set to approximately 0, and the linear solenoid L0
To the switching element T
The drive duty ratio “DUTY” of r0 is switched to half of the control duty ratio “duty_OLG”. When the power supply voltage + B further decreases from 10.9 V, the drive duty ratio “DUTY” of the switching element Tr0 increases according to the voltage change by current feedback,
Eventually, when the power supply voltage + B reaches 4.9V,
It will reach 100%. Therefore, in this case,
The load current i can be controlled to the target current until the power supply voltage + B decreases from 14 V in the normal state to about 5 V, which is half or less of the voltage value.

As described above, according to the energization control device of this embodiment, although the voltage range in which the load current i can be controlled can be increased, the load current i
Of the drive duty ratio for controlling the load current i can be made larger than before (from 0 to 50% in the past, it can be made 0 to 70%). Can be controlled with high resolution, and the control accuracy of the load current i can be improved.

When the voltage drop generated in the load resistance switching circuit 20 is switched via the switch SW0, the drive duty ratio "DUTY" is also switched.
It is possible to prevent the load current i from suddenly changing with the switching of the voltage drop amount, and to control the load current i to the target current in a stable manner. In FIG. 3, the load current i does not fluctuate before and after the switching of the voltage drop amount. To achieve this, the voltage drop amount in the load resistance switching circuit 20 is changed when the switch SW0 is switched. The resistance value of the resistor R0 may be set so as to be about one half of the power supply voltage + B.

Here, in the energization control processing shown in FIG. 2A, switching of the ON / OFF state of the switch SW0 (in other words, switching of the voltage drop amount in the load resistance switching circuit 20) is performed by controlling the duty ratio. Although the description has been made on the assumption that the “duty_OLG” is less than the set value (90%), the switching of the switch SW0 is controlled by the load resistance switching circuit 20 depending on whether the power supply voltage + B is normal or low. In order to prevent the voltage applied to the linear solenoid L0 from largely fluctuating, the power supply voltage + B is detected, and the switch SW0 is switched based on the detected power supply voltage + B. ON ・ O
The FF state may be switched.

For this purpose, as shown by the dotted line in FIG. 1, a voltage detection circuit 12 for directly detecting the power supply voltage + B is provided.
And a part of the energization control process executed on the control circuit 10 side may be changed as shown in FIG. That is, in the energization control process shown in FIG. 2A, the processes of S140, S150, and S170 functioning as voltage drop adjusting means (the process shown in the diagram) are changed as shown in FIG. After calculating the control duty ratio "duty_OLG" in step S135, the power supply voltage + B detected by the voltage detection circuit 12 is fetched in step S135, and in step S140 ', the fetched power supply voltage + B is set to a preset set voltage. (For example, 10.9 V) or more, and the power supply voltage + B is 1
If it is 0.9 V or more, the process proceeds to S150 to switch S
If W0 is turned off and the power supply voltage + B is less than 10.9 V, the process proceeds to S170 and the switch SW0 is turned on. However, as shown in FIG. Even if the load current i decreases to
The control can be performed without any problem within the range of 1A to 1A, and the same effect as above can be obtained.

On the other hand, in this embodiment, the load resistance switching circuit 2
0, the resistor R0 and the switch SW0 connected in parallel to the resistor R0 by applying the voltage drop means of claim 3.
By switching the ON / OFF state of the switch SW0, the voltage drop amount in the load resistance switching circuit 20 can be set to any one of a predetermined value determined by the resistance value of the resistor R0 and the load current i, or substantially zero. Although the load resistance switching circuit 20 is described in FIG.
As shown in (a), a plurality of resistors having different resistance values may be used.

That is, in the load resistance switching circuit 20 shown in FIG. 4A, by applying the voltage drop means according to claim 4, two resistances having different resistance values are provided on the current supply path to the linear solenoid L0. R1, R2 are connected to switches SW1,
SW2, a series circuit of the resistor R1 and the switch SW1, and a resistor R2 and a switch S1.
A switch SW3 is connected in parallel to a series circuit with W2.

According to the load resistance switching circuit 20, one of the three switches SW1 to SW3 is turned on, and the other two switches are turned off. At a predetermined value determined by the resistance value of the resistor R1 and the load current i when the switch SW1 is turned on, and the resistor R2 when the switch SW2 is turned on.
A predetermined value determined by the resistance value of the
Since it can be set to any of 0 when W3 is on,
FIG. 4 shows a part of the energization control process executed on the control circuit 10 side.
If the load resistance is changed as shown in FIG.
, The amount of voltage drop is switched between three levels, and the change in the voltage applied to the linear solenoid L0 caused by the fluctuation of the power supply voltage + B can be further reduced.

That is, the flowchart shown in FIG. 4B shows the processing of S140 to S180 in which the switch SW0 is switched and the drive duty ratio "DUTY" is set in the energization control processing shown in FIG. After the control duty ratio “duty_OLG” is calculated in S130 described above, first, in S142.
, The calculated control duty ratio “duty_OLG”
Judge whether it is smaller than A1%.

If the control duty ratio "duty_OLG" is less than A1%, the switch SW1 is turned on and the switches SW2 and SW3 are turned off in S152, thereby reducing the voltage drop amount in the load resistance switching circuit 20. , A value determined by the load current i and the resistance value of the resistor R1.
At 62, the control duty ratio “duty_OLG” is set as it is as the drive duty ratio “DUTY”, and the subsequent S190
Move to

On the other hand, when it is determined in S142 that the control duty ratio “duty_OLG” is A1% or more,
Proceeding to S144, the control duty ratio "duty_OLG"
Determines whether the value is smaller than A2% which is a value larger than A1%. Then, the control duty ratio “duty_OL
If “G” is less than A2%, in S154 the switch S
By turning on W2 and turning off the switches SW1 and SW3, the amount of voltage drop in the load resistance switching circuit 20 is set to a value determined by the resistance value of the resistor R2 having a smaller resistance value than the resistance R1 and the load current i. Then, in S164, the drive duty ratio “DUTY” is set as the control duty ratio “duty_O”.
The value “duty_OLG / B2” obtained by dividing “LG” by the set value B2 is set, and the flow shifts to subsequent S190.

When it is determined in S144 that the control duty ratio “duty_OLG” is not less than A2%,
The process proceeds to S156, in which the switch SW3 is turned on, and the switches SW1 and SW2 are turned off, thereby setting the voltage drop amount in the load resistance switching circuit 20 to substantially zero.
In step 6, a value "duty_OLG / B3" obtained by dividing the control duty ratio "duty_OLG" by the set value B3 larger than the set value B1 is set as the drive duty ratio "DUTY", and the flow shifts to subsequent S190.

Accordingly, the configuration of the load resistance switching circuit 20 and the energization control processing in the control circuit 10 are described in FIGS. 4 (a) and 4 (b).
If the voltage is changed as shown in FIG. 7, the amount of voltage drop in the load resistance switching circuit 20 can be changed according to the control duty ratio “duty_OLG”.
It is possible to increase the power supply voltage range in which the current can be controlled by switching to the stages and reducing the change in the voltage applied to the linear solenoid L0 caused by the fluctuation of the power supply voltage + B.

When the apparatus shown in FIG. 4 is actually constructed, for example, the maximum value of the control duty ratio "duty_OLG" is set to 300%, 90% for A1% and 19% for A2%.
0%, and set values B2,
What is necessary is just to set the value 2 and the value 3 to B3, respectively.

In the flowchart shown in FIG. 4B, in S142 and S144, the power supply voltage + B is used in place of the control duty ratio "duty_OLG", and the higher the power supply voltage + B, the more the load resistance switching circuit 20 operates. The resistance of the load resistance switching circuit 20 may be switched so that the voltage drop amount (in other words, the resistance value) increases.

Further, in the first embodiment, the switch SW0 or SW1 to SW3 as the switch means used for switching the resistance value of the load resistance switching circuit 20.
May use a semiconductor element such as a transistor or a switch having a contact such as a relay. [Second Embodiment] Next, FIG. 5 shows a second embodiment of the present invention.
1 is an electric circuit diagram illustrating a configuration of an entire energization control device according to an embodiment.

The energization control device of this embodiment is basically
The configuration is the same as that of the energization control device of the first embodiment shown in FIG. 1, and is different from the energization control device of the first embodiment in the energization path between the switching element Tr0 and the linear solenoid L0, as is apparent from FIG. In addition, an applied voltage variable circuit 30 composed of a variable resistor is provided in place of the load resistance switching circuit 20.

The applied voltage variable circuit 30 makes the resistance value continuously variable so that the applied voltage to the linear solenoid L0 is kept substantially constant without being affected by the fluctuation of the power supply voltage + B. This is to enable control, and corresponds to a voltage drop unit according to claim 6. The applied voltage variable circuit 30 is configured to change a resistance value based on a command from the control circuit 10.
In this embodiment, it is constituted by a switched capacitor.

That is, the applied voltage variable circuit 30 connects the capacitor C0 and both ends of the capacitor C0 to a connection point (point a) to the switching element Tr0 and a connection point (point b) to the linear solenoid L0, respectively. Switches SWa and SW for switching between ground and a ground line
b. Switches SWa and SWb are
This is for switching at a high speed whether the both ends of the capacitor C0 are connected to the respective connection points (points a and b) or grounded, and a semiconductor element such as a transistor is used.

The control circuit 10 switches the ON / OFF states of the switches SWa and SWb alternately at a high speed to charge the capacitor C0 from the point a and charge the capacitor C0 from the capacitor C0 to the point b. The electric charge is discharged, whereby the resistance value R of the applied voltage variable circuit 30 is changed by the switching speed of the switches SWa and SWb (frequency f
[Hz]), a predetermined value “R = 1 / (C ×
f) "(where C is the capacitance [F] of the capacitor C0).

Next, in the control circuit 10 of this embodiment,
An energization control process executed for energization control of the linear solenoid L0 will be described with reference to a flowchart and a map shown in FIG. In order to execute the energization control process described below, the energization control device of the present embodiment is provided with a voltage detection circuit 12 for detecting the power supply voltage + B.

As shown in FIG. 6A, when the energization control process is started, first, in S210, the power supply voltage + B detected by the voltage detection circuit 12 is fetched, and in S220, the fetched power supply voltage is fetched. Based on the power supply voltage + B, a target resistance value r of the applied voltage variable circuit 30 is calculated, and in S230, the applied voltage variable circuit 30 is adjusted so that the resistance value R of the applied voltage variable circuit 30 becomes the target resistance value r. The process as the voltage drop adjusting means according to claim 6 is executed by a procedure such as controlling.

When calculating the target resistance value r of the applied voltage variable circuit 30 in S220, as shown in FIG. 6B, a map for calculating the target resistance value r from the power supply voltage + B is used. used. The processing of S230 is the same as that of FIG.
Using the map as shown in (c), the respective switches SWa and SWb in the applied voltage variable circuit 30 are set to O from the target resistance value r.
A switching speed (1 / f) for N / OFF is calculated, and each switch SWa, SWb is turned ON at the calculated switching speed.
The procedure is such that a control signal for switching the OFF state is output to the applied voltage variable circuit 30. By this processing, the resistance value R of the applied voltage variable circuit 30 is controlled to the target resistance value r.

When the resistance value R of the applied voltage variable circuit 30 is controlled to the target resistance value r corresponding to the power supply voltage + B in this manner, the current flows through the linear solenoid L0 in S240, as in S110 described above. The target current to be calculated is calculated, and in S250, A
The load current i actually flowing through the linear solenoid L0 is calculated based on the input data from the / D converter 8.

In the following S260, the above-mentioned S13
Similarly to 0, based on the deviation between the target current and the load current i,
The control duty ratio “duty_OLG” for controlling the load current i to the target current is calculated, and in S270, the control duty ratio “duty_OLG” is output to the drive circuit 2 as the drive duty ratio as it is to thereby obtain the drive circuit. 2, the switching element T is driven by a drive signal (PWM signal) pulse-width modulated with the control duty ratio “duty_OLG”.
r0 is duty-driven.

As described above, in the energization control device of the second embodiment, the resistance value of the load resistance switching circuit 20 provided on the energization path of the linear solenoid L0 is different from that of the first embodiment. Control duty ratio "duty_OL
By controlling the resistance value of the applied voltage variable circuit 30 provided on the energization path of the linear solenoid L0 in accordance with the power supply voltage + B, instead of switching stepwise according to the power supply voltage + B and the linear solenoid L0. To prevent the applied voltage from changing according to the fluctuation of the power supply voltage + B.

Therefore, according to the energization control device of the second embodiment, not only the same effects as in the energization control device of the first embodiment are obtained, but also the voltage applied to the linear solenoid L0 is
The load current i is always controlled to a constant voltage irrespective of the change of the power supply voltage + B, so that the load current i can always be controlled at a control duty ratio set within a range of 0 to 100%. That is, according to the energization control device of the second embodiment, the load current i can always be controlled with the maximum resolution, and the control accuracy of the load current i is further improved as compared with the energization control device of the first embodiment. can do. Third Embodiment Next, FIG. 7 is an electric circuit diagram showing a configuration of an entire energization control device according to a third embodiment to which the present invention (specifically, claims 7 to 9) is applied.

The energization control device of this embodiment includes a DC power supply 40
And a 42V power supply configured by serially connecting three batteries each having a normal power supply voltage of 14V. The negative side of the DC power supply 40 is grounded to a ground line, and the first side for 42V output is connected to the positive side.
An output terminal t1 is provided. In addition, a second output terminal t2 for 28 V output, and 1
Third output terminals t3 for 4V output are provided respectively.

The energization control device of this embodiment controls the amount of current flowing through the linear solenoid L0 as in the first and second embodiments described above. There are provided three current supply paths from the output terminals t1, t2, t3 of the DC power supply 40 to the linear solenoid L0. On each of these conduction paths, three switching elements Tr1, Tr2, Tr3 each comprising a PNP transistor are provided, and one of these three switching elements Tr1 to Tr3 is ON / OFF controlled. By holding the remaining two in the OFF state, one of the outputs from the three output terminals t1 to t3 of the DC power supply 40 is selected as the voltage applied to the linear solenoid L0, and the load current i is controlled. Have been able to.

The switching elements Tr1 to Tr
3 is connected to the corresponding output terminals t1 to t3, and the collector of the PNP transistor is
It is connected to the linear solenoid L0. The base is connected to the drive circuit 2, and furthermore, resistors Rb1 and Rb1 for stabilizing the base voltage are provided between the base and the emitter.
2 and Rb3 are connected. In the following description, a voltage selection circuit including the three switching elements Tr1 to Tr3 is referred to as a voltage selection circuit 50.

Next, one end of the linear solenoid L0 on the side opposite to the switching elements Tr1 to Tr3 has the same potential as the negative side of the DC power supply 40 via the current detection resistor Rs as in the above-described embodiments. Grounded to the ground line. Then, the voltage across the current detection resistor Rs is amplified by the amplifier circuit 4, and the voltage is applied to one of the switching elements Tr1 by the integrating circuit 6 including the resistor Ra and the capacitor Ca.
After the fluctuation components associated with the switching operation of Tr3 to Tr3 are removed, the signals are input to the control circuit 10 via the A / D converter 8. The output voltages from the output terminals t1 to t3 of the DC power supply 40 are detected by the voltage detection circuit 12, and the detection data is also input to the control circuit 10.

On the other hand, the control circuit 10 is composed of a microcomputer having a CPU, ROM, RAM, etc. as in the above-described embodiments, and flows from the input data from the A / D converter 8 to the linear solenoid L0. Current (load current) i, a control duty ratio for controlling the load current i to a target current is set, and based on the control duty ratio, the switching element Tr1
To Tr3 by duty driving, the load current i
Is controlled to the target current.

Hereinafter, the energization control process executed by the control circuit 10 will be described. FIG. 8A is a flowchart showing the energization control process.
FIG. 8B is a flowchart illustrating a modification of the energization control process of FIG.

As shown in FIG. 8A, the control circuit 10 first calculates the target current of the linear solenoid L0 in S310 in the same manner as in S110 described above, and in S320, in the same manner as in S120 described above. The load current i is calculated, and in S330, the control duty ratio “duty_OLG” is calculated as in S130 described above. In this embodiment, S
The maximum value of the control duty ratio “duty_OLG” calculated at 330 is set to be 300% which is three times the normal value.

When the control duty ratio “duty_OLG” is calculated in S330 in this way, this time, in S340,
Similarly to S142 described above, the calculated control duty ratio “duty_OLG” is equal to the set value A1% (for example, 90%).
It is determined whether it is smaller than.

If the control duty ratio "duty_OLG" is less than the set value A1%, in S360, the drive duty ratio "DUTY" is set as the control duty ratio "duty_OLG".
In step S370, the set drive duty ratio “DUTY” is changed to the drive duty ratio “duty drive” for duty-driving the switching element Tr3 that applies the output voltage from the third output terminal t3 to the linear solenoid L0. DUTY "is output to the drive circuit 2, and the process is temporarily terminated. As a result, the drive circuit 2 drives the drive signal (PWM) pulse-width modulated with the drive duty ratio “DUTY”.
Signal), the switching element Tr3 is duty driven, and the other switching elements Tr1 and Tr2 are O
Hold in FF state.

On the other hand, in S340, when it is determined that the control duty ratio “duty_OLG” is equal to or more than the set value A1%, in S350, similar to S144 described above,
It is determined whether or not the control duty ratio “duty_OLG” is smaller than a set value A2% (for example, 190%).

If the control duty ratio "duty_OLG" is less than the set value A2%, in S380, the drive duty ratio "DUTY" is set as the control duty ratio "duty_OLG".
Divided by the set value B2 (for example, the value 2), “duty_OLG /
B2 ”is set, and in S390, the set drive duty ratio“ DUTY ”is changed to a drive duty ratio for duty-driving the switching element Tr2 that applies the output voltage from the second output terminal t2 to the linear solenoid L0. This is output to the drive circuit 2 as "DUTY", and the process is once ended. As a result, the drive circuit 2 duty-drives the switching element Tr2 with the drive signal (PWM signal) pulse-width modulated at the drive duty ratio “DUTY”,
OFF for other switching elements Tr1 and Tr3
Hold in state.

If the control duty ratio "duty_OLG" is equal to or greater than the set value A2%, the control duty ratio "duty_OLG" is divided by the set value B3 (for example, value 3) in S400 as the drive duty ratio "DUTY". Value “duty_OLG / B
3 ”is set, and in S410, the set drive duty ratio“ DUTY ”is changed to a drive duty ratio for duty-driving the switching element Tr1 that applies the output voltage from the first output terminal t1 to the linear solenoid L0. This is output to the drive circuit 2 as "DUTY", and the process is once ended. As a result, the drive circuit 2 duty-drives the switching element Tr1 with the drive signal (PWM signal) pulse-width modulated at the drive duty ratio “DUTY”,
OFF for other switching elements Tr2 and Tr3
Hold in state.

In FIG. 8, the determination processing of S340 and S350 indicated by a dotted line corresponds to the switching element selection means according to claim 7, and S360 to S410.
The processing described above functions together with the driving circuit 2 as a driving means. As described above, according to the energization control device of the third embodiment, if the control duty ratio “duty_OLG” calculated to control the load current i to the target current is less than A1%, the DC power supply 40 The energization control to the linear solenoid L0 is performed using the output voltage from the third output terminal t3 having a low output voltage, and the control duty ratio “duty_O”
If “LG” is less than A2%, the energization control to the linear solenoid L0 is performed using the output voltage from the second output terminal t2, and if the control duty ratio “duty_OLG” is A2% or more, the DC power supply 40 Using the output voltage from the first output terminal t1 having the highest output voltage, the linear solenoid L0 is used.
Control of energization of the

The control duty ratio “duty_OLG” is
When the control duty ratio “duty_OLG” is less than A1%, the control duty ratio “duty_OLG” is set as the drive duty ratio “DUTY” of the switching element Tr3, and the control duty ratio “duty_OLG” is set. Is less than A2%, a value obtained by dividing the control duty ratio “duty_OLG” by the set value B2 is used as the drive duty ratio “DUTY” of the switching element Tr2, and the control duty ratio “duty_OLG” is A2% or more. In some cases, a value obtained by dividing the control duty ratio “duty_OLG” by a set value B3 larger than the set value B2 is used as the drive duty ratio “DUTY” of the switching element Tr1.

For this reason, according to the energization control device of the third embodiment, as shown in FIG.
If the output voltages Vt1, Vt2, Vt3 from 1 to t3 are normal voltages (42V, 28V, 14V), the third
The energization control using the output voltage Vt3 from the output terminal t3 is executed, and when the output voltage from each of the output terminals t1 to t3 decreases and the control duty ratio “duty” becomes equal to or more than the set value A1%, the linear solenoid L0 Is switched to the energization control using the output voltage Vt2 from the second output terminal t2 having a higher voltage than the third output terminal t3, and the output voltages from the output terminals t1 to t3 further decrease. When the control duty ratio "duty" becomes equal to or more than the set value A2%, the energization control to the linear solenoid L0 is performed by the output voltage Vt1 from the first output terminal t1 having a higher voltage than the second output terminal t2.
Is switched to the energization control using.

That is, in the energization control device of the third embodiment, like the energization control devices of the first and second embodiments, the load resistance switching circuit 20 for generating a voltage drop on the energization path of the linear solenoid L0, Providing an applied voltage variable circuit 30;
By changing the resistance value, instead of suppressing the applied voltage to the linear solenoid L0 from changing in accordance with the power supply voltage + B, the voltage selection circuit 50 sets an energizing path from the DC power supply 40 to the linear solenoid L0. By using and selectively switching, the applied voltage to the linear solenoid L0 is prevented from greatly changing according to the fluctuation of the power supply voltage.

Therefore, in the energization control device of the third embodiment, similarly to the energization control devices of the first and second embodiments,
Prevents fluctuations in the voltage applied to the linear solenoid L0 caused by fluctuations in the power supply voltage, and increases both the voltage range in which the load current i can be controlled and the change range of the drive duty ratio to improve the control accuracy of the load current i. It is possible to do.

In particular, in the power supply control device of this embodiment, it is not necessary to provide the load resistance switching circuit 20 and the applied voltage variable circuit 30 as voltage drop means on the power supply path to the linear solenoid L0. It is possible to eliminate wasteful power consumption in each circuit and reduce the amount of power consumption by the power supply control device.

In the energization control process shown in FIG. 8A, switching of the energization path used for energization control of the linear solenoid L0 (in other words, switching of the switching element used for energization control) is controlled by the control duty ratio “ duty_OLG "
However, the switching of the energization path may be performed based on the output voltage from the DC power supply 40. And for this, FIG.
In the energization control process shown in (a), the determination process (the process shown in the figure) of S340 and S350 functioning as the switching element selecting means may be changed, for example, as shown in FIG. 8B.

That is, in the flowchart shown in FIG. 8B, the control duty ratio "duty_OLG"
Is calculated, the output voltages Vt1 and Vt2 from the first and second output terminals t1 and t2 detected by the voltage detection circuit 12 are taken in S335. Then, in S340 ′, it is determined whether the output voltage Vt2 from the second output terminal t2 is equal to or higher than the set value VBa (for example, 20 V), and the output voltage Vt2 is equal to or higher than the set voltage VBa. Then, the above S
360, and conversely, the output voltage Vt2 becomes the set voltage VB.
If it is less than a, the process proceeds to S350 ', and the output voltage Vt1 from the first output terminal t1 is set to the set value VBb (for example, 3
0V) or more. And the output voltage Vt1
If is equal to or higher than the set voltage VBb, the flow shifts to S380 described above. Conversely, if the output voltage Vt1 is lower than the set voltage VBb, the flow shifts to S400 described above.

Even if the energization control process is executed as described above, the energization path to the linear solenoid L0 can be switched as the power supply voltage of the DC power supply 40 decreases, as shown in FIG. Therefore, the same effect as above can be obtained. As described above, three embodiments of the first to third embodiments have been described as embodiments of the present invention. However, the present invention is not limited to the above-described embodiments, and employs various aspects. be able to.

For example, in each of the embodiments described above, the PNP transistor is used as the switching element Tr0 for controlling the current supplied to the linear solenoid L0 as an inductive load. However, the present invention provides an NPN transistor as the switching element. , Or an energization control device using an n-channel or p-channel power MOSFET,
The same effects can be obtained by applying in the same manner as in the above embodiments.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram illustrating a configuration of an entire energization control device for a linear solenoid according to a first embodiment.

FIG. 2 is a flowchart illustrating an energization control process performed by a control circuit according to the first embodiment.

FIG. 3 is a time chart for explaining an operation of energization control according to the first embodiment.

FIG. 4 is an explanatory diagram illustrating a modified example of the load resistance switching circuit and the energization control process of the first embodiment.

FIG. 5 is an electric circuit diagram illustrating a configuration of an entire energization control device for a linear solenoid according to a second embodiment.

FIG. 6 is a flowchart illustrating an energization control process performed by a control circuit according to a second embodiment.

FIG. 7 is an electric circuit diagram illustrating a configuration of an entire energization control device for a linear solenoid according to a third embodiment.

FIG. 8 is a flowchart illustrating an energization control process performed by a control circuit according to a third embodiment.

FIG. 9 is a time chart illustrating the operation of energization control according to a third embodiment.

FIG. 10 is an explanatory diagram illustrating a relationship among a drive duty ratio of a switching element, a load current, and a power supply voltage.

[Explanation of symbols]

2 ... Drive circuit, 4 ... Amplifier circuit, 6 ... Integrator circuit, 8 ... A /
D converter, 10: control circuit, 12: voltage detection circuit, 20
... Load resistance switching circuit, 30 ... Applied voltage variable circuit, 40 ...
DC power supply, 50: voltage selection circuit, L0: linear solenoid, Rs: current detection resistor, Tr0, Tr1, Tr2, T
r3: switching element, R0, R1, R2, R3: resistor, SW0, SW1, SW2, SW3, SWa, SWb
... switch, C0 ... capacitor.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshimasa Kobayashi 1-1-1 Showa-cho, Kariya-shi, Aichi F-Term in Denso Co., Ltd. 5H420 BB03 BB13 CC02 DD02 DD06 EA11 EA23 EA37 EA39 EB01 EB09 EB16 EB26 EB37 FF04 FF25 GG07 LL04 NB03 NB12 NB22 NB24 NC06 NC27 NE15

Claims (9)

[Claims] 1. A switching element provided on a current supply path from a DC power supply to an inductive load, for conducting and blocking the path, current detecting means for detecting a load current flowing through the inductive load, and the current detection Means for calculating a control duty ratio required to control the load current to the target current based on the load current detected by the means and the target current; and a duty ratio calculated by the duty ratio calculation means. A drive means for turning on / off the switching element in accordance with a control duty ratio. An inductive load energizing control device comprising: a voltage provided on the energizing path, for decreasing an applied voltage to the inductive load. In accordance with the control duty ratio calculated by the duty ratio calculation means, the voltage drop amount increases as the control duty ratio decreases. And a voltage drop adjusting means for adjusting the amount of voltage drop by the voltage drop means. 2. A switching element provided on a current supply path from a DC power supply to an inductive load, for conducting / cutting off the path, current detecting means for detecting a load current flowing through the inductive load, and the current detection Means for calculating a control duty ratio required to control the load current to the target current based on the load current detected by the means and the target current; and a duty ratio calculated by the duty ratio calculation means. A drive unit for turning on / off the switching element in accordance with a control duty ratio. An inductive load energization control device comprising: a power supply voltage detection unit for detecting a power supply voltage of the DC power supply; A voltage drop means for reducing an applied voltage to the inductive load; and a power supply voltage high in response to the power supply voltage detected by the power supply voltage detection means. Extent such that the voltage drop amount increases, the voltage drop means the voltage drop control circuit and, energization control apparatus of the inductive load, characterized in that a for adjusting the amount of voltage drop due to. 3. The voltage drop means comprises a resistor connected in series with the current path and a switch connected in parallel with the resistor. The voltage drop adjusting means includes an ON / OFF switch of the switch.
3. The inductive load energization control device according to claim 1, wherein an amount of voltage drop by said voltage drop means is adjusted by switching an FF state. 4. The voltage drop means comprises a plurality of resistors which can be connected in series to the current path and have different resistance values, and the voltage drop adjusting means switches a resistor connected in series to the current path. 3. The inductive load energization control device according to claim 1, wherein the amount of voltage drop by said voltage drop means is adjusted. 5. The driving means according to an operation of the voltage drop adjusting means so that a load current flowing through the inductive load does not suddenly change with a switching operation of the resistance by the voltage drop adjusting means. 5. The inductive load energization control device according to claim 3, wherein a drive duty ratio for actually turning on / off the switching element is set based on the control duty ratio calculated by the duty ratio calculation means. . 6. The voltage drop means comprises a variable resistor capable of continuously adjusting a resistance value, and the voltage drop adjustment means changes a resistance value of the variable resistor according to the power supply voltage. Claim 2
An inductive load energization control device as described in the above. 7. A switching element provided on an energization path from a DC power supply to an inductive load, for conducting / cutting off the path, current detection means for detecting a load current flowing through the inductive load, and the current detection Means for calculating a control duty ratio required to control the load current to the target current based on the load current detected by the means and the target current; and a duty ratio calculated by the duty ratio calculation means. A drive unit for turning on / off the switching element according to a control duty ratio. An inductive load energization control device comprising: a DC power supply having a plurality of output terminals capable of outputting different DC voltages as the DC power supply; By using a voltage, a plurality of energizing paths from each output terminal of the DC power supply to the inductive load are formed, and the switch is provided in each of the plurality of energizing paths. The ring element is provided, in accordance with the calculated control duty ratio by the duty ratio calculation unit, the larger the control duty ratio, so that the output voltage is higher the output terminal of the switching element,
An inductive load energization control device, comprising: switching element selection means for selecting a switching element used for control by the driving means and fixing the other switching elements to an OFF state. 8. A switching element provided on an energizing path from a DC power supply to an inductive load, for conducting / cutting off the path, current detecting means for detecting a load current flowing through the inductive load, and the current detection Means for calculating a control duty ratio required to control the load current to the target current based on the load current detected by the means and the target current; and a duty ratio calculated by the duty ratio calculation means. A drive unit for turning on / off the switching element according to a control duty ratio. An inductive load energization control device comprising: a DC power supply having a plurality of output terminals capable of outputting different DC voltages as the DC power supply; By using a voltage, a plurality of current paths from each output terminal of the DC power supply to the inductive load are formed, and each of the plurality of current paths is connected to the switch. Provided with a ring element, and a power supply voltage detecting means for detecting a power supply voltage output from at least one output terminal of the DC power supply, in accordance with the detected power supply voltage at the power supply voltage detecting means,
A switching element selecting means for selecting the switching element used for control by the driving means, and fixing the other switching elements to an OFF state, so that the lower the power supply voltage is, the higher the output voltage becomes the switching element on the output terminal side; An inductive load energization control device, comprising: 9. The driving unit according to an operation of the switching element selection unit so that a load current flowing through the inductive load does not suddenly change in accordance with a switching element selection operation by the switching element selection unit. 9. The inductive load energization control according to claim 7, wherein a drive duty ratio for actually turning on / off the switching element is set based on the control duty ratio calculated by the duty ratio calculation means. apparatus.