JPH11327602A - Driving device for inductive load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily improve the accuracy of a control current by a driving device at a low cost in the driving device for feedback-controlling a current flowing to an inductive load. SOLUTION: In this driving device, a command signal of a duty factor corresponding to a target current is outputted from a microcomputer 4, it is converted to a command voltage Vs by a duty to voltage conversion circuit 20, error signals VERR for which the deviation of the voltage Vs and a detection voltage obtained through a current detection resistor Rs and an amplifier circuit 10 is integrated are generated in an error signal generation circuit 30 and a solenoid L is energized and controlled corresponding to the error signals VERR. In this case, correction data for correcting a control error generated by the variation of the respective circuits are stored in an EEPROM 70 and when the microcomputer 4 generates the command signal, the duty factor of the command signal is corrected by using the correction data. Also, the correction data are set based on the deviation of the command voltage Vs and an error voltage VERR obtained at the time of making a constant current flow to the resistor Rs and making the command signal corresponding to the constant current output from the microcomputer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an inductive load that performs feedback control of a current flowing through the inductive load.

[0002]

2. Description of the Related Art Conventionally, as a driving device for an inductive load, as disclosed in Japanese Patent Laid-Open No. Hei 5-217737, a current actually flowing through an inductive load is supplied to a current path provided in a current path of the inductive load. The detection voltage is detected as a voltage across the detection resistor, and the detected voltage is the same as the output (command voltage) from a conversion circuit that converts a command signal (such as a duty signal whose duty ratio is controlled) output from the microcomputer into a voltage. There is known a device that performs feedback control of a current supplied to an inductive load such that

In this type of device, for example, as shown in FIG. 6, the voltage between both ends of a current detection resistor Rs connected in series to an energizing path of a linear solenoid L as an inductive load is determined by:
The duty signal representing the target current output from the microcomputer 4 is amplified by the amplifier circuit 10 including the operational amplifier OP1 and the resistors R1, R2, R3, and R4, and is converted into a voltage by the duty-voltage conversion circuit 20. By doing so, a detection voltage and a command voltage corresponding to the current flowing through the linear solenoid L are respectively generated. Then, the amplification circuit 10
Output voltage (detection voltage) from the DUTY-voltage conversion circuit 2
The output voltage (command voltage) from 0 is input to an error signal generation circuit (integration / amplification circuit) 30 including an operational amplifier OP2, a resistor R5, and a capacitor C1, and detected by the error signal generation circuit 30. An error signal is generated by integrating the deviation between the voltage and the command voltage. Then, the error signal is input to a drive signal generation circuit 40 including a comparator 42 and an inverter 44, and the drive signal generation circuit 40
By comparing the error signal with the triangular wave, a drive signal (pulse width modulation signal) for controlling the current supplied to the linear solenoid L is generated.

The energizing path of the linear solenoid L includes
A switching element that conducts and cuts off the path (in the figure,
PNP transistor TR1) and resistors R6, R7 for turning on the PNP transistor TR1 by supplying a bias current to the PNP transistor TR1 when the drive signal generated by the drive signal generation circuit 40 is at a low level. And a diode D that continuously supplies current to the linear solenoid L with the high voltage generated in the linear solenoid L when the drive signal is inverted from low to high level and the PNP transistor TR1 is turned off. Is provided, and a current corresponding to the duty ratio of the drive signal generated by the drive signal generation circuit 40 flows through the linear solenoid L via the drive circuit 50.

[0005]

However, in the conventional driving device configured as described above, since the circuit elements constituting the driving device have manufacturing variations, for example,
In FIG. 6, if the current detection resistor Rs has a manufacturing variation of ± 5%, the current flowing through the linear solenoid L is also ± 5%.
A control error occurs due to the variation in circuit elements.

In particular, in the above-described conventional driving device, a command signal from a microcomputer is converted into a command voltage by a duty-voltage conversion circuit 20, and the command voltage and a detection voltage output from the amplifier circuit 10 are converted. An error signal for feedback control is generated by comparison in the error signal generation circuit 30, and therefore, compared to a device in which the calculation of the control amount for feedback control is realized by the arithmetic processing of the microcomputer 4, There are many circuit elements that cause control variations, and control accuracy is deteriorated.

That is, in the above-mentioned conventional driving device, the current detection system and the current control system for feedback control of the current flow are all constituted by electronic circuits, and the Duty-voltage conversion circuits 20 and Error signal generation circuit 30,
Since all the drive signal generation circuits 40 have variations in circuit elements, the variation in control (current control error) becomes extremely large when the variations in these circuit elements are superimposed.

On the other hand, in order to solve such a problem, for example, laser trimming or the like is required because the manufacturing variation of the offset voltage / current of the operational amplifier (op-amp) constituting each of the above circuits greatly affects the variation of the control current value. It is conceivable to adjust the characteristic values of the circuit elements constituting the operational amplifier by using the method described above, or to increase the accuracy of circuit elements such as a current detection resistor and a resistor connected to the operational amplifier. Such measures increase the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a drive device for feedback-controlling a current flowing through an inductive load such as a linear solenoid, so that the accuracy of the control current by the drive device can be improved simply and at low cost. The purpose is to:

[0010]

According to a first aspect of the present invention, there is provided a driving apparatus for driving an inductive load, wherein the command voltage generating means includes a target current to be supplied from the microcomputer to the inductive load. Is output, and the command voltage generating means converts the command signal into a command voltage. Further, the actual current flowing through the inductive load is detected by the current detecting means, and the error signal generating means integrates the difference between the detected voltage from the current detecting means and the command voltage from the command voltage generating means. Generate an error signal. Then, based on the generated error signal, the energization control unit causes the current flowing through the inductive load to be the target current,
Energize the inductive load.

Further, in the driving device configured as described above, a current control error occurs due to a variation in circuit elements constituting the command voltage generating means, the current detecting means, and the error signal generating means. Correction data storage means for preliminarily storing correction data for reducing a control error caused by a circuit error of each means by correcting a command signal output from the microcomputer is provided, and the microcomputer stores a command corresponding to a target current. The signal is corrected based on the correction data stored in the correction data storage means, and the corrected command signal is output to the command voltage generation means.

Therefore, according to the inductive load driving device of the present invention, the current control error caused by the variation (circuit error) of the circuit elements constituting the command voltage generating means, the current detecting means, and the error signal generating means. Can be reduced. Further, in order to reduce the control error, it is not necessary to adjust the characteristics of the circuit elements of each means constituting the control system by the above-described trimming or the like, so that the productivity of the driving device can be increased and the driving device can be realized at low cost. .

Here, the correction data to be stored in the storage means must be generated by actually operating the drive device in an inspection process after the manufacture of the drive device. Is performed using a dedicated device, it is necessary to change the device to be specified or to switch its operation every time a driving device having a different specification is adjusted, which is troublesome. Also, when rewriting the correction data due to a change over time, a change in use conditions, or the like, a dedicated device is required.

Therefore, it is desirable that the driving device be capable of generating correction data and storing it in the storage means. To this end, the driving device may be configured as described in claim 2. In other words, the inductive load driving device according to the second aspect is provided with A / D conversion means for A / D converting the output voltage from the command voltage generation means and the error signal generation means and inputting the output voltage to the microcomputer. When the microcomputer receives a correction data creation command indicating that the reference current has been given to the current detection means, the microcomputer outputs a command signal corresponding to the reference current to the command voltage generation means, and outputs the command signal via the A / D conversion means. Output voltages from the command voltage generation and conversion means and the error signal generation means are fetched, correction data is obtained based on the fetched voltages, and stored in the storage means.

Therefore, according to the driving device of the present invention, when a preset reference current is supplied to the current detecting means and a correction data creation command indicating the fact is input to the microcomputer, the correction data is automatically generated. The adjustment work when storing the correction data in the storage means or rewriting the correction data can be performed extremely simply by using the constant current circuit that generates the reference current. Becomes possible.

Here, in the second aspect, when the correction data is created, the microcomputer takes in the outputs from the command voltage generation means and the error signal generation means via the A / D conversion means. This is because the difference between the outputs from these means corresponds to a control error generated when the microcomputer outputs a command signal corresponding to the reference voltage.

That is, if the output of the command voltage generating means and the output of the current detecting means completely match, the output of the error signal generating means will be the same as the output of the command voltage generating means, but the characteristic variation of the elements constituting the circuit will not occur. As a result, an error occurs in the outputs of the command voltage generation means and the current detection means. Also, since the error signal generating means itself also has variation in element characteristics,
An error occurs in the output. Therefore, by monitoring both the error signal generation means and the command voltage generation means, the control error of the entire circuit can be confirmed.

In order for the microcomputer to generate the correction data based on the outputs from the command voltage generation means and the error signal generation means, for example, a method for previously obtaining the correction data from the output deviation from each of the above means is provided. The correction data creation data is stored in the microcomputer in advance, and when the microcomputer generates the correction data, the correction data corresponding to the output deviation from each of the above means is used by using the correction data creation data. You may ask for it.

However, when the data for creating correction data is used as described above, it is necessary to accurately set the data itself and to store the data in a microcomputer. Therefore, when the microcomputer creates the correction data, a command signal corresponding to the reference current is output to the command voltage generation means, and is taken in through the A / D conversion means. Once the outputs from the command voltage generating means and the error signal generating means are fetched, the command output to the command voltage generating means is thereafter performed so that the difference between the fetched output voltages is equal to or less than a predetermined voltage. The signal may be changed to obtain a command signal in a region where the difference between the output voltages is equal to or less than a predetermined voltage, and correction data may be created from the command signal and the reference current.

That is, according to this configuration, the control error (control accuracy) obtained from the deviation of the output voltage from the command voltage generating means and the error signal generating means becomes equal to or less than a predetermined value.
Correction data can be created accurately, and it is not necessary to create correction data generation data in advance and store it in a microcomputer for the purpose of creating correction data.
The device configuration can be simplified.

In the driving device according to the second and third aspects, when the correction data is created by the microcomputer, the control error obtained from the difference between the outputs from the command voltage generating means and the error signal generating means is: Since it is a control error when a command signal corresponding to the reference current is output from the microcomputer, a command signal corresponding to various target currents output by the microcomputer can be corrected using the correction data. It is desirable that correction data be set for each command signal output by the computer (in other words, a target current corresponding to the command signal) and stored in the storage means.

However, setting the correction data for each command signal output by the microcomputer complicates the operation of setting the correction data, and also increases the capacity of the storage means for storing the correction data. Therefore, when the correction data is actually created by the microcomputer, the correction signals corresponding to the vicinity of the maximum value and the vicinity of the minimum value of the command signal (in other words, the target current) output from the microcomputer are respectively set.
A control error with respect to the type of reference current is obtained from a difference between outputs from the command voltage generation means and the error signal generation means, two types of correction data corresponding to each control error are created, and stored in the storage means. Good.

In other words, according to this configuration, at the time of inductive load energization control, a correction value of the command signal corresponding to the target current is obtained by interpolation from the two types of correction data stored in the storage means. The command signal can be set by using the value, and the command signal output from the microcomputer can be satisfactorily corrected without increasing the number of correction data to be stored in the storage means (and hence the capacity of the storage means). It becomes possible to do.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an entire configuration of an embodiment of the present invention in which the present invention is applied to a linear solenoid driving device that controls the energization of a linear solenoid as an inductive load.

The drive device of the present embodiment includes, for example, a brake hydraulic pressure for vehicle control (for example, a brake hydraulic pressure for anti-skid control, a transmission hydraulic pressure for automatic transmission control) which is pumped from a hydraulic pump driven by an internal combustion engine. Etc.) (current flowing through a linear solenoid L for driving a hydraulic control valve for controlling hydraulic pressure to a predetermined operating oil pressure) (solenoid current)
In the same manner as the conventional linear solenoid L driving device shown in FIG. 6, (1) a duty signal (command signal) in which a duty ratio is controlled in accordance with a target current to flow through the linear solenoid L. Microcomputer (2) which outputs FIG. 2 (a)), (2) converts a command signal from microcomputer 4 into a voltage signal Vs (command voltage; see FIG. 2 (b)) corresponding to the duty ratio. , Duty-voltage conversion circuit 2 as command voltage generation means
0, (3) a current detection resistor Rs for detecting the current flowing through the linear solenoid L, (4) a voltage signal (detection voltage) corresponding to the command voltage Vs by amplifying the voltage across the current detection resistor Rs
(5) an error signal VERR (see FIG. 2 (c)) by integrating a deviation between the detection voltage from the amplifier circuit 10 and the command voltage Vs to generate an error signal VERR. Error signal generation circuit 30, (6) Error signal VERR
And triangular wave (see FIG. 2D),
A drive signal generation circuit 40 for generating a drive signal (pulse width modulation signal; see FIG. 2E) for controlling a current supplied to the linear solenoid L, (7) a drive signal from the drive signal generation circuit 40 A switching element (PNP transistor TR) provided in the energization path of the linear solenoid L
1) Turn on / off the solenoid current (Fig. 2 (f)
Drive circuit 50 for duty control of the driving circuit 50).

Since each of the above circuits has the same configuration as that of the conventional device shown in FIG. 6, the description of the internal configuration is omitted. In the present embodiment, the function as the current detection means according to the first aspect is realized by the current detection resistor Rs and the amplifier circuit 10. Further, the Duty-voltage conversion circuit 20 is configured to convert a command signal (duty signal) from the microcomputer 4 into an analog voltage signal (command voltage) Vs by an integration process or the like, for example. For example, as shown in FIG. 3 (b), when the duty ratio of the command signal from the microcomputer 4 is the minimum value (18%), the DC 0.
A command voltage Vs of 6 V is output and the microcomputer 4
When the duty ratio of the command signal from is the maximum value (90%), a command voltage Vs of DC 3 V is output.

Next, the driving device of this embodiment includes (8)
A / D conversion circuit 60 as A / D conversion means for A / D converting the command voltage Vs and the error signal VERR and inputting them to the microcomputer 4, (9) The microcomputer 4 should flow to the linear solenoid L EEPROM 7 as storage means for storing correction data for correcting the duty ratio of the command signal generated corresponding to the target current
0 is provided.

At the time of the normal operation of controlling the brake oil pressure to a predetermined operating oil pressure, the microcomputer 4
A target current to be passed to the linear solenoid L is set based on the target hydraulic pressure of the brake hydraulic pressure.
A basic duty ratio of a duty signal to be output to the duty-voltage conversion circuit 20 is set using a duty ratio setting map shown by a solid line in FIG. And outputs a command signal corresponding to the corrected duty ratio to the Duty-voltage conversion circuit 20.

That is, in this embodiment, the map for setting the basic duty ratio is such that the target current to be passed through the linear solenoid L is set to the minimum current 0 in the preset control range as shown by the solid line in FIG. .2A, the basic duty ratio is set to the minimum value (18%), and when the target current to be passed through the linear solenoid L is the maximum current 1A, the basic duty ratio is set to the maximum value (90%). Have been.

Assuming that there is no variation in the circuit elements in each of the above circuits and that each circuit operates in the same manner as at the time of design, the microcomputer 4 outputs a solenoid current of 1 A
When a command signal with a duty ratio of 90% is output to make the duty ratio, the duty-voltage conversion circuit 20 outputs a command voltage of 3V, and the drive circuit 50 is driven so that the detection voltage from the amplifier circuit 10 becomes 3V. This drive controls the solenoid current to 1 A, and the microcomputer 4 sets the duty ratio to 1 A in order to make the solenoid current 0.2 A.
If a command signal of 8% is output, the duty-voltage conversion circuit 20
From the amplifier circuit 10 to drive the drive circuit 50 so that the detection voltage from the amplifier circuit 10 becomes 0.6 V. By this drive, the solenoid current is controlled to 0.2 A. .

However, since the Duty-voltage conversion circuit 20, the error signal generation circuit 30, the current detection resistor Rs, and the amplification circuit 10 have variations in circuit elements, actually, in order to control the solenoid current, Even if the microcomputer 4 outputs the command signal obtained from the above map, the solenoid current cannot be controlled to the target current, and the brake hydraulic pressure cannot be controlled to the desired hydraulic pressure.

Therefore, in this embodiment, in order to correct a control error due to a variation in circuit elements constituting each of the above circuits, a basic duty ratio set using a map shown by a solid line in FIG. Is corrected using the correction data stored in the EEPROM 70, for example, as shown in FIG.
As shown by the dotted line in (a), the target current-command signal (duty ratio) characteristics are adapted to the characteristics of each of the above-mentioned circuits used for current control, thereby ensuring the control accuracy of the solenoid current (and hence the brake oil pressure). They are trying to do it.

The EEPROM 70 has a basic duty ratio (9) for controlling the solenoid current to a maximum current of 1 A.
0%) and the basic duty ratio (18) for controlling the solenoid current to the minimum current of 0.2 A.
%) Is stored, and when the microcomputer 4 actually controls the solenoid current, the correction value corresponding to the target current to be passed to the linear solenoid L is obtained by linearizing the correction data in the EEPROM 70. By interpolating, a correction value corresponding to the target current to be passed through the linear solenoid L is obtained, and the correction value is used to correct the basic duty ratio corresponding to the target current obtained from the above map, so that the duty ratio of the command signal is changed. Set.

Next, the correction data in the EEPROM 70 is created by actually operating the driving device and measuring a control error in a shipping inspection process of the driving device,
It is stored in the EEPROM 70. Hereinafter, a procedure for creating the correction data will be described. When the correction data is created in the shipping inspection process of the driving device, as shown in FIG. 4, instead of connecting the linear solenoid L to the driving device, a reference current (for example, when the solenoid current is controlled by the driving device). Is connected to a constant current source Is that generates a maximum current 1A and a minimum current 0.2A). The microcomputer 4
In order to switch the operation mode from the normal operation mode in which the above-described hydraulic control is performed to the inspection mode, two test terminals T1 and T2 provided in the microcomputer 4 in advance are provided.
2, switches SW1 and SW2 for grounding the test terminals T1 and T2, and resistors R11 and R12 for applying the power supply voltage Vd to the test terminals T1 and T2, respectively. When the switch SW1 is closed and the test is started with the test terminal T1 at the ground level, the microcomputer 4
Enters the inspection mode and creates correction data according to the procedure shown in FIG.

That is, as shown in FIG. 5, when the microcomputer 4 is started, first, in S110 (S indicates a step), the switch SW1 is closed, and whether or not the test terminal T1 is at the ground level is determined. In other words, it is determined whether or not the operation mode of the microcomputer 4 is the inspection mode. If it is determined in S110 that the test terminal T1 is not at the ground level, the operation mode is determined to be the normal operation mode, and a control program for controlling the current supplied to the linear solenoid L is executed.
When the operation shifts to the normal control and it is determined that the test terminal T1 is at the ground level, the operation mode is determined to be the inspection mode, and the process shifts to S120.

In the present embodiment, when the test terminal T1 is set to the ground level in order to operate the microcomputer 4 in the inspection mode, the microcomputer 4 is instructed to issue the correction data creation command according to claim 2. Will be input. Next, in S120, it is determined whether the switch SW2 is closed and the test terminal T2 is at the ground level. The switch SW2 is set to a closed state when the maximum current 1A during the solenoid current control is supplied from the constant current source Is by an external operation by the inspector or automatic switching by the inspection device, and the solenoid current is switched from the constant current source Is to the solenoid current. It is set to an open state when a minimum current of 0.2 A during control is supplied. In S120,
If the switch SW2 is in the closed state, the current detection resistance Rs is set to 1
If the current of A flows and the switch SW2 is in the open state, it is determined that a current of 0.2 A flows to the current detection resistor Rs.

If the switch SW2 is in the closed state, the microcomputer 4 determines that the mode is the 1A mode, and calculates the correction data for flowing the maximum current 1A to the linear solenoid L by the processing of S130 to S190. If the switch SW2 is in the open state, It is determined that the mode is the 2A mode, and the correction data for causing the minimum current of 0.2 A to flow through the linear solenoid L is calculated by the processes of S200 to S260.

That is, in S120, the current operation mode is 1
If it is determined that the mode is the A mode, first in S130, the duty ratio of the command signal output to the duty-voltage conversion circuit 20 is set to the basic duty ratio (90%) for controlling the solenoid current to 1A. And outputs a command signal at this basic duty ratio.

Next, at S140, the voltage level of the error signal VERR output from the error signal generation circuit 30 is calculated.
The voltage level of the command voltage Vs output from the duty-voltage conversion circuit 20 after the start of the output of the command signal is represented by A / D
It is fetched through the conversion circuit 60, and it is determined whether or not the absolute value of the difference (VERR-Vs) between the voltage levels of these signals is equal to or less than a predetermined determination value (for example, 60 mV).

That is, when the operation mode of the microcomputer 4 is set to the 1A mode, since the constant current of 1 A flows through the current detection resistor Rs, the detection voltage output from the amplifier circuit 10 is: The voltage level corresponds to the current 1A. On the other hand, since the microcomputer 4 outputs a command signal with a basic duty ratio of 90% corresponding to the current 1A, the duty-voltage conversion circuit 20
Is also at a voltage level corresponding to the current 1A. At this time, the current detection resistor Rs, the amplifier circuit 10, the Duty
-If there is no variation between the voltage conversion circuit 20 and the error signal generation circuit 30, the output from the amplifier circuit 10 and the output from the Duty-voltage conversion circuit 20 are both 3V at the time of design (see FIG. 3B).
And the error signal VERR output from the error signal generation circuit 30 also becomes 3 V, and the command voltage Vs and the error signal VERR
Is zero. However, in practice, since these circuits vary, the command voltage Vs and the error signal VER
A deviation occurs between R and all the error components of each circuit. Then, in S140, this deviation is taken in as a control error peculiar to the driving device, and the control error becomes
It is determined whether or not the value is equal to or less than a set determination value based on the control accuracy required for the driving device. Note that this determination value is
When the control error obtained from the difference between the command voltage Vs and the error signal VERR in the 1A mode is set to 60 mV or less in the 1A mode as described above, the current control accuracy of the driving device is ± 2%. (= 60 mV / 3V).

If it is determined in S140 that the control error exceeds the determination value, the flow shifts to S150 where a comparison is made between the error signal VERR and the command voltage Vs, and the error signal VERR is large. In this case (VERR> Vs), in S160, the duty ratio of the command signal is decremented. Conversely, when the error signal VERR is small (VERR <VERR <Vs).
For Vs), in S170, the duty ratio is updated by incrementing the duty ratio. Note that S
At 160 and S170, the value at which the duty ratio is decremented or incremented is naturally determined by the output resolution of the microcomputer 4, but in the present embodiment, the duty ratio is changed at a resolution of, for example, 0.1%. . Then, in S180, a command signal generated with the updated duty ratio is output to the Duty-voltage conversion circuit 20, and the process returns to S140.

As a result, the microcomputer 4 has 1A
At the beginning of the operation in the mode, even if the deviation (absolute value) between the error signal VERR and the command voltage Vs exceeds the determination value, S
During the repetition of the processing of 150 to 180, the deviation between the error signal VERR and the command voltage Vs becomes equal to or smaller than the determination value.

If it is determined in S140 that the deviation between the error signal VERR and the command voltage Vs has become equal to or smaller than the determination value, the program proceeds to S190, where the duty ratio of the command signal currently set and the initial value in S130. The correction data D1 for correcting the basic duty ratio when the target current is 1A is obtained from the deviation from the basic duty ratio (90%) set in the above. The correction data D1 is stored in the 1A correction data storage area of the EEPROM 70. Then, the process returns to S110.

Next, if it is determined in S120 that the current operation mode is the 0.2A mode, the process proceeds to S200.
, The duty ratio of the command signal output to the Duty-voltage conversion circuit 20 is set to the basic duty ratio (18%) for controlling the solenoid current to 0.2 A, and the command signal is output at this basic duty ratio. Then, in S210, the voltage level of the error signal VERR output from the error signal generation circuit 30 and the voltage level of the command voltage Vs output from the duty-voltage conversion circuit 20 after the start of the output of the command signal are respectively changed. , Via the A / D conversion circuit 60, and determines whether or not the absolute value of the difference (VERR-Vs) between the voltage levels of these signals is equal to or less than a predetermined determination value (for example, 12 mV). . Note that this determination value indicates that the current control accuracy when controlling the solenoid current to 0.2 A is ± 2% (= 12%).
mV / 0.6V) or less.

If it is determined in S210 that the absolute value of the deviation between the error signal VERR and the command voltage Vs (ie, the control error) exceeds the determination value, the process proceeds to S220.
A magnitude comparison between the error signal VERR and the command voltage Vs is performed. If the error signal VERR is large (VERR> Vs), S2
At 30, the duty ratio of the command signal is decremented,
Conversely, if the error signal VERR is small (VERR <Vs), the duty ratio is updated by incrementing the duty ratio in S240. And the following S
At 180, the command signal generated with the updated duty ratio is output to the Duty-voltage conversion circuit 20, and again at S2
Move to 10.

Next, in S210, the error signal VERR
If it is determined that the difference between the command voltage Vs and the command voltage Vs has become equal to or smaller than the determination value, in S260, the duty ratio of the command signal currently set and the basic duty ratio (90%) initially set in S200. From the deviation of the target current from 0.
At 2A, correction data D2 for correcting the basic duty ratio is obtained, and this correction data D2 is stored in an EEPROM.
70 and stored in the 0.2A correction data storage area.
Move to 110.

As described above, in the driving device according to the present embodiment, when the microcomputer 4 controls the solenoid current, the basic duty ratio of the command signal corresponding to the target current is determined by using a preset map. And the basic duty ratio is corrected using the correction data stored in the EEPROM 70 to set the duty ratio of the command signal.

For this reason, according to the driving device of this embodiment,
Even if the circuit elements constituting the current detection resistor Rs, the amplification circuit 10, the duty-voltage conversion circuit 20, and the error signal generation circuit 30 have a variation, a control error caused by the variation is transmitted to the command signal on the microcomputer 4 side. By correcting the duty ratio, the control accuracy of the solenoid current (and hence the brake oil pressure) can be improved. Further, since it is not necessary to adjust the characteristics of the circuit elements constituting these circuits by the above-described trimming or the like in order to increase the control accuracy, the productivity of the drive device can be increased and the drive device can be realized at low cost.

The correction data is obtained by connecting the constant current source Is to the driving device when the driving device is shipped, for example.
When the microcomputer 4 is operated in the inspection mode (specifically, the 1A mode and the 0.2A mode) while supplying a constant current of 1 A or 0.2 A from the microcomputer 4, it is automatically created by the processing of the microcomputer 4 and the EEPROM
Since it is stored in M70, the creation of correction data and E
There is no need to prepare a special device for storage in the EPROM 70, and the creation and storage of correction data can be performed extremely easily.

As described above, one embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various embodiments can be adopted. For example, in the above embodiment, as the correction data, the maximum current (1 A) and the minimum current (0 .1) within the control range in which the drive device controls the solenoid current.
2A), the two points of correction data D1 and D2 corresponding to
When stored in the PROM 70 and actually controlled, the correction data of the basic duty ratio corresponding to the target current is obtained by linearly interpolating the correction data D1 and D2 at the two points. May be a value obtained from a control error obtained when a constant current is supplied at a current value within the control range, and the number of correction data may be increased to three or more.

In the above embodiment, the microcomputer 4 outputs a duty signal whose duty ratio is controlled as a command signal in order to control the solenoid current.
Then, digital data representing the target current may be output as the command signal. In this case, instead of the duty-voltage conversion circuit 20, D / A for converting digital data output as a command signal from the microcomputer 4 into an analog voltage signal (command voltage).
A conversion circuit may be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an entire driving device for a linear solenoid according to an embodiment.

FIG. 2 is a time chart showing an operation waveform of each part of the driving device.

FIG. 3 is an explanatory diagram illustrating operations of a microcomputer and a duty-voltage conversion circuit.

FIG. 4 is an explanatory diagram illustrating a connection state of an external device to a drive device when creating correction data.

FIG. 5 is a flowchart illustrating the operation of the microcomputer when creating correction data.

FIG. 6 is a configuration diagram illustrating an example of a conventional linear solenoid driving device.

[Explanation of symbols]

4 microcomputer, 10 amplifier circuit, 20 Du
ty-voltage conversion circuit, 30 error signal generation circuit, 40 drive signal generation circuit, 50 drive circuit, 60 A / D conversion circuit, 70 EEPROM, T1, T2 test terminals, S
W1, SW2: switch, Is: constant current source, L: linear solenoid, Rs: current detection resistor.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // H01F 7/18 H01F 7/18 S

Claims (3)

[Claims] A microcomputer for outputting a command signal representing a target current flowing to the inductive load; a command voltage generating means for converting a command signal from the microcomputer into a command voltage; and an actual current flowing to the inductive load. Current detection means for generating a detection voltage corresponding to the actual current, and an error signal generated by integrating a difference between a detection voltage from the current detection means and a command voltage from the command voltage generation means. Error signal generating means; and an error signal generated by the error signal generating means.
And a conduction control means for controlling conduction of the inductive load so that a current flowing through the inductive load becomes the target current. A driving apparatus for an inductive load, comprising: The microcomputer further includes a correction data storage unit in which correction data for reducing a control error caused by a circuit error of the signal generation unit by correcting the command signal is stored in advance, and the microcomputer further includes a command corresponding to the target current. A driving apparatus for an inductive load, wherein a signal is corrected based on correction data stored in the correction data storage means, and a corrected command signal is output to the command voltage generation means. 2. An A / D conversion means for A / D converting an output voltage from the command voltage generation means and the error signal generation means and inputting the converted voltage to the microcomputer, wherein the microcomputer has the current detection means Receives a correction data creation command indicating that a reference current has been given to the reference voltage generator, outputs a command signal corresponding to the reference current to the command voltage generator, and outputs the command voltage generation and converter via the A / D converter. 2. The inductive load driving device according to claim 1, wherein an output voltage from the error signal generating means is fetched, the correction data is obtained based on the fetched voltages, and the correction data is stored in the storage means. 3. When the microcomputer creates the correction data, a difference between an output voltage from the command voltage generation unit and an output voltage from the error signal generation unit, which is taken in through the A / D conversion unit, is set in advance. By changing the command signal output to the command voltage generating means so as to be equal to or less than the set predetermined voltage, a difference between output voltages from the command voltage generating means and the error signal generating means is set in advance. 3. The inductive load driving device according to claim 2, wherein a command signal in a region where the voltage is equal to or lower than a predetermined voltage is obtained, and the correction data is created from the command signal and the reference current.