JPH082724Y2 - Load control device - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention has been carried out in a wide range of fields such as so-called factor automation equipment, numerical control machines, transportation machines such as automobiles, and general home appliances, and is used in motors and motors. The present invention relates to a device for driving and controlling a load having an inductance component such as an electromagnetic solenoid.

2. Description of the Related Art From a load having the inductance component, a magnetic field is generated due to a change in load current during driving, and an electromagnetic induction effect of the magnetic field causes a current to flow in a pattern on a wiring board, resulting in electromagnetic noise. appear. On the other hand, it is indispensable to use an electronic circuit element such as a micro computer in each of the above-described devices that use a load having the inductance component. Therefore, in order to prevent the malfunction of the electronic circuit element due to the mixing of the noise, in the typical prior art, countermeasures on the circuit such as strengthening the ground pattern of the wiring board or changing the wiring layout, or shielded wire or Various measures have been taken such as electromagnetic shielding using a shield material and noise removal using a capacitor and a filter element.

Problems to be Solved by the Invention In the above-described conventional techniques, noise is prevented from being mixed,
Further, the effect of noise is reduced by removing the mixed noise. Therefore, it cannot be said that it is a perfect countermeasure against noise, and the structure becomes complicated, the number of parts and man-hours increase, and the cost increases.

An object of the present invention is to provide a load control device capable of reliably avoiding the influence of electromagnetic noise with a simple structure.

Means for Solving the Problems The present invention provides a drive control means for receiving an input signal from an external circuit and drivingly controlling a load based on the input signal, and a time for cutting off a load during driving or a time near the time. In addition, the load control device includes input control means for stopping the input from the external circuit of the drive control means.

Operation According to the present invention, the drive control means receives the input signal from the external circuit via the input control means, and drives and controls the load based on the input signal. The input control means stops the receiving operation of the drive control means at a time at or near the cutoff feature when the drive control means releases the drive state by interrupting the load while the drive control means is driving the load.

Therefore, even if electromagnetic noise is generated due to the interruption of the load, especially the load having an inductance component such as a motor or an electromagnetic solenoid, by the input control means,
The reception operation of the drive control means is stopped at or near the time when the electromagnetic noise is generated, and in this way, when the electromagnetic noise is generated, it is possible to avoid mixing the noise itself into the drive control means. With a simple configuration, it is possible to avoid the influence of electromagnetic noise and drive-control the load without malfunction.

First Embodiment FIG. 1 is a block diagram showing an electrical configuration of a fuel injection control device 1 for an automobile, which is a load control device according to an embodiment of the present invention. In this fuel injection control device 1, a processing circuit 2 realized by, for example, a microcomputer or the like.
Controls the opening / closing of the electromagnetic solenoid 4 of the fuel injection valve, which is a load, based on the rotation signal of the internal combustion engine detected by the crank angle detector 3. The rotation signal is derived for each 180 ° crank angle when the internal combustion engine is, for example, a 4-cylinder 4-cycle internal combustion engine.

The processing circuit 2 is connected via a bus 5 to an external circuit 6 such as a signal processing circuit that processes signals from a constant speed traveling device or various sensors used for fuel injection control (for example, a throttle opening sensor). It The count value of the free running counter 7 is also input to the processing circuit 2.
The number of pulses input from is counted cyclically. The processing circuit 2 calculates a count value corresponding to the timing at which fuel injection should be performed based on the count value thus input and the rotation signal, and derives the calculation result to the latch circuit 9.

The count value stored in the latch circuit 9 is the comparator
It is given to one input of 10, and the count value of the free running counter 7 is inputted to the other input of this comparator 10. When the count value of the free-running counter 7 matches the count value stored in the latch circuit 9, the comparator 10 derives a set signal to the flip-flop 12 via the line 11 to set the flip-flop 12. The output of the flip-flop 12 is given to the base of the switching element 13.
The collector of 13 is connected to a high level power source + B via the electromagnetic solenoid 4, and the emitter is grounded.

The set signal derived from the comparator 10 on the line 11 is also applied to the processing circuit 2. When the set signal is derived from the comparator 10 to the flip-flop 12, the set signal interrupts the processing circuit 2. It is entered as input. When the processing circuit 2 receives this interrupt input,
The conduction period W1 of the electromagnetic solenoid 4 is calculated based on the input result from the external circuit 6 or the like, and the conduction period W1 is calculated.
When is passed, the reset signal is derived to the flip-flop 12.

The output of the flip-flop 12 is also given to the cutoff detection circuit 14, and when the fall of the output from the flip-flop 12 is detected, the cutoff detection circuit 14 derives the output to the down counter 15 and starts the subtraction operation. Let The down counter 15 performs the subtraction operation in response to the pulse from the oscillation circuit 16, and outputs the input prohibition signal to the processing circuit 2 via the line 17 during the subtraction operation. The initial value of the down counter 15 is preset by the processing circuit 2 based on the rotation signal or the like.

A timer circuit 18 is also provided in association with the processing circuit 2, and a timer interrupt signal is derived from the timer circuit 18 at every predetermined constant period W2, and the processing circuit 2 receives the timer interrupt signal. When the input prohibition signal is not input during the period, the arithmetic operation is stopped and the input operation from the external circuit 6 is performed via the bus 5.

FIG. 2 is a timing chart for explaining the operation. When the rotation signal shown in FIG. 2 (1) is input from the crank angle detector 3, the processing circuit 2 receives the rotation signal shown in FIG. 2 (5) during the period W5 between the falling time t1 and the time t2 of this rotation signal. ) Interrupting the operation of calculating the rotational speed of the internal combustion engine, as shown in FIG.
Is calculated.

Thus, at time t3, when the count value stored in the latch circuit 9 and the count value of the free-running counter 7 match, the flip-flop 12 is set and the switching element 13 is turned on as shown in FIG. 2 (2). It is conducted. Further, at this time, the set signal is also input to the processing circuit 2, and the processing circuit 2 receives the conduction period W1 of the switching element 13, that is, the conduction period W1 from time t3 to time t4, as shown in FIG. The cutoff time t5 is calculated and obtained. At the time t5, the reset output is derived to the flip-flop 12, and the switching element 13 is cut off.

Thus, at time t5, when the switching element 13 is cut off, the magnetic force of the electromagnetic solenoid 4 changes as shown by the broken line in FIG. 2 (2), and as a result, as shown in FIG. 2 (3). In addition, electromagnetic noise is generated within the period W3.

On the other hand, from the timer circuit 18, the predetermined cycle
For each W2, the timer interrupt signal is derived over the period W4,
As a result, the processing circuit 2 performs the operation operation of the timer interrupt as shown in FIG. In this case, in the timer interrupt period W4 between time t1 and time t5 when no electromagnetic noise is generated, the processing circuit 2 sends data to the external circuit 6 via the bus 5 as shown in FIG. Derive a signal requesting the transmission of In response to this transmission request signal, data is derived from the external circuit 6 as shown in FIG. 2 (9) and read into the processing circuit 2.

On the other hand, from time t5 to time when electromagnetic noise occurs
During the timer interrupt period W4 between t6, as shown by the virtual line in FIG. 2 (6), the operation operation of the timer interrupt is not performed, and accordingly, as shown by the virtual line in FIG. 2 (8). In addition, the transmission request signal is not derived from the processing circuit 6, and the processing circuit 2 invalidates the input data and prohibits the reading of the data, as indicated by a virtual line in FIG. 2 (9). . The processing operation of the main routine of the processing circuit 2 during the above-described operation is the second operation.
As shown in FIG. 4 (4), interrupt calculation processing is performed during the periods W4 and W5.

FIG. 3 is a flow chart for explaining the operation of the interruption interrupt calculation. At step n1, the cutoff time of the switching element 13 shown at the time t4 is set. At step n2, the initial value of the down counter 15, that is, the input prohibition period W3 is set, and another operation is started.

FIG. 4 is a flow chart showing the output operation of the transmission request signal shown in FIG. 2 (8). Step n11
It is determined whether or not it is within the input prohibition period W3, and if not, the transmission request signal is derived in step n12 to move to another operation, and if it is within the input prohibition period W3 in step n11, the other is directly performed. Move on to the operation.

FIG. 5 is a flow chart showing the data input operation from the external circuit 6 shown in FIG. 2 (9). In step n21, it is judged whether or not it is within the input prohibition period W3, and if not, the data is read in step n22, and another operation is started. Also step n21
If it is within the input prohibition period W3, the operation directly proceeds to another operation.

As described above, in the fuel injection control device 1 according to the present invention, when data is input from the external circuit 6 from the output of the timer circuit 18 during the timer interrupt period W4, the electromagnetic solenoid 4 having the inductance component is cut off. Since a predetermined period W3 from the time is set as an input prohibition period and the input of data from the external circuit 6 is invalidated within this input prohibition period W3, malfunction due to the influence of electromagnetic noise can be prevented with a simple configuration. It can be avoided without fail.

In the above-described embodiment, the input from the external circuit 6 is stopped only when the switching element 13 is cut off. However, as another embodiment of the present invention, the same applies when the switching element 13 is conducting. The input from the external circuit 6 may be stopped.

As described above, according to the present invention, when the input control means cuts off the load from the state in which the drive control means is driving the load to release the drive state, the time at or near the cutoff time In the above, since the receiving operation of the drive control means is stopped, even if electromagnetic noise is generated due to interruption of a load having an inductance component such as a motor or an electromagnetic solenoid, the input control means The receiving operation of the drive control means is stopped at or near the time when electromagnetic noise occurs. Therefore, when the electromagnetic noise is generated, it is possible to avoid the noise itself from being mixed in the drive control means. Therefore, the influence of the electromagnetic noise can be avoided and the load can be drive-controlled without malfunction by a simple configuration. .

[Brief description of drawings]

FIG. 1 is a block diagram showing the electrical construction of a fuel injection control device 1 according to an embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation, and FIGS. 3-5 are for explaining the operation. It is a flow chart for. 1 ... Fuel injection control device, 2 ... Processing circuit, 3 ... Crank angle detector, 4 ... Electromagnetic solenoid, 6 ... External circuit, 13 ... Switching element, 14 ... Break detection circuit, 15
...... Down counter

Claims (1)

[Scope of utility model registration request] 1. A drive control means for receiving an input signal from an external circuit and driving-controlling a load based on the input signal, and a time at which a load being driven is cut off or a time in the vicinity thereof.
An input control means for stopping an input from an external circuit of the drive control means, the load control device.