JPH0556686A - Motor driver - Google Patents

Abstract

PURPOSE:To display abnormality by means of a stabilized constant display signal without switching the display signal at the time of overcurrent. CONSTITUTION:A triggerable one-shot multivibrator 8 is triggered with an output from an overcurrent detecting circuit 3 at the time of overcurrent to produce a display signal of constant level for a predetermined interval. Consequently, a display means 9 can display abnormality for a predetermined interval.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor drive device which detects an overcurrent flowing in a motor to limit the current and self-diagnose when an abnormality occurs.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the structure of a conventional motor drive device. In FIG. 3, reference numeral 1 is a motor, 2 is a current detection resistor connected between the power source 10 and the motor 1, and 3 is an overcurrent detection circuit for detecting an overcurrent flowing in the motor 1 by the current detection resistor 2. Is a current limiting circuit that limits the current of the motor 1 based on the overcurrent detected by the overcurrent detection circuit 4, reference numeral 5 is a timer circuit that controls the switching of the motor 1 during overcurrent (particularly when abnormal overcurrent occurs), and 6 is A motor driver circuit for driving the motor 1, 7 is a control signal input to the motor driver circuit 6, and 9 is a display means for displaying an abnormality at the time of overcurrent according to the output of the overcurrent detection circuit 3. The display means 9 may be a lamp or a buzzer as long as it informs a person. FIG. 4 shows an output of the overcurrent detection circuit 3 at the time of detecting an overcurrent input to the input terminal A of the display means 9. In other words, it is a display signal to the display means 9 when an abnormality is detected.

The operation of this conventional example will be described with reference to FIGS. 3 and 4. When a control signal input 7 is applied to the motor driver circuit 6 and the motor 1 is rotationally driven, the current flowing through the motor 1 is taken out as a signal by the current detection resistor 2 and input to the overcurrent detection circuit 3. When the current flowing through the motor 1 is an overcurrent, the overcurrent detection circuit 3
The overcurrent is detected by. The output of the overcurrent detection circuit 3 at the time of this overcurrent is given to the current limiting circuit 4,
The current limiting circuit 4 controls the motor driver circuit 6 so that the motor driver circuit 6 limits the current of the motor 1.
Further, when the above-mentioned overcurrent is abnormally large, the timer circuit 5 operates as a timer for a certain period by the output of the current limiting circuit 4, whereby the motor driver circuit 6 turns off the current of the motor 1 for a certain period and then turns it on. That is, the timer circuit 5
Thus, the motor 1 is switching-controlled. The output of the overcurrent detection circuit 3 is given to the display means 9,
In the switching state as shown in FIG. 4, a display for notifying the overcurrent is performed.

[0004]

Since the conventional motor drive device is constructed as described above, an abnormal display is made by the display means when an overcurrent is detected. This abnormal display is made in the switching state and the switching speed is changed. Depending on the situation, it was difficult to tell whether the data was abnormal or normal, and there was a problem that misdiagnosis was possible.

The present invention has been made in order to solve the above problems, and a motor drive capable of performing a stable and easy-to-understand abnormality display without switching the abnormality display during overcurrent detection. The purpose is to provide a device.

[0006]

The motor drive device according to the present invention is connected between the overcurrent detection circuit 3 and the display means 9 and operates by using the output of the overcurrent detection circuit 3 as a trigger to the display means 9. The retriggerable one-shot multi-vibrator 8 for sustaining the display signal of 1) for a certain period is provided.

[0007]

The retriggerable multivibrator 8 uses the output of the overcurrent detection circuit 3 as a trigger to keep the display signal to the display means 9 for a certain period. That is, the multivibrator 8 is triggered by the output of the overcurrent detection circuit 3 at the time of overcurrent, and outputs the display signal of the same level state for a certain period. As a result, the display means 9 can display an abnormality for a certain period.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of a motor drive device according to an embodiment of the present invention. In FIG. 1, components corresponding to those shown in FIG. 3 are designated by the same reference numerals, and their description will be omitted. In FIG. 1, reference numeral 8 is a retriggerable one-shot multivibrator that operates by using the output of the overcurrent detection circuit 3 at the time of overcurrent as a trigger and keeps the display signal to the display means 9 for a certain period. That is, the multivibrator 8 is provided with an overcurrent detection circuit 3 when an overcurrent occurs.
The input switching signal is kept at a constant level for a certain period.

FIG. 2 shows an overcurrent detection signal at the time of an overcurrent inputted to the input terminal B of the retriggerable one-shot multivibrator 8 and an overcurrent inputted to the input terminal A of the display means 9 (at the time of abnormality detection). ) Is a display signal.

Next, the operation of this embodiment will be described with reference to FIGS. Since the overcurrent detection operation, the current limiting operation, and the switching control operation have been described in the conventional example, they are omitted here. Now, the newly provided retriggerable one-shot multivibrator 8 is triggered by the output (overcurrent detection signal) of the overcurrent detection circuit 3 that detects the overcurrent of the motor 1, and outputs a signal of the same level for a certain period. .. Referring to FIG. 2, when an overcurrent occurs, the output of the overcurrent detection circuit 3 (overcurrent detection signal to the input terminal B of the multivibrator 8) is a level-switched signal. The vibrator 8 outputs a high level signal (display signal to the input terminal A of the display means 9) for a certain period. Therefore, when the overcurrent is generated, the display signal becomes high level for a certain period, and the display means 9 can perform a constant and stable abnormality display.

[0011]

As described above, according to the present invention, since the retriggerable one-shot multivibrator is provided between the overcurrent detection circuit and the display means, the abnormal display during overcurrent detection does not switch. Therefore, it is possible to perform a constant, stable and easy-to-understand abnormality display, and therefore, the effect of improving the accuracy of abnormality diagnosis is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a motor drive device according to an embodiment of the present invention.

FIG. 2 is a signal waveform diagram showing an overcurrent detection signal and a display signal at the time of overcurrent in this embodiment.

FIG. 3 is a block diagram showing a configuration of a conventional motor drive device.

FIG. 4 is a signal waveform diagram showing a display signal at the time of overcurrent in this conventional example.

[Explanation of symbols]

 1 Motor 2 Current Detection Resistor 3 Overcurrent Detection Circuit 4 Current Limiting Circuit 8 Retriggerable One-Shot Multivibrator 9 Display Means 10 Power Supply

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[Procedure amendment]

[Submission date] June 17, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

The operation of this conventional example will be described with reference to FIGS. 3 and 4. When a control signal input 7 is applied to the motor driver circuit 6 and the motor 1 is rotationally driven, the current flowing through the motor 1 is taken out as a signal by the current detection resistor 2 and input to the overcurrent detection circuit 3. When the current flowing through the motor 1 is an overcurrent, the overcurrent detection circuit 3
The overcurrent is detected by. The output of the overcurrent detection circuit 3 at the time of this overcurrent is given to the current limiting circuit 4,
The current limiting circuit 4 controls the motor driver circuit 6 so that the motor driver circuit 6 limits the current of the motor 1.
Further when the overcurrent, a certain period timer operation timer circuit 5 by the output of the current limiting circuit 4, thereby the motor driver circuit 6 to the current for a period of time off motor 1, also then on. That is, the timer circuit 5 controls the switching of the motor 1. Further, the output of the overcurrent detection circuit 3 is given to the display means 9, and a display for notifying the overcurrent time is displayed in the switching state as shown in FIG.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 1 motor 2 current detection resistor 3 overcurrent detection circuit 4 current limiting circuit 5 timer circuit 8 retriggerable one-shot multivibrator 9 display means 10 power supply

Claims (1)

[Claims] 1. A motor connected to a power source via a current detection resistor, an overcurrent detection circuit for detecting an overcurrent flowing in the motor by the current detection resistor, and an overcurrent detection circuit for detecting the overcurrent. A motor drive device comprising: a current limiting circuit that limits the current of the motor based on an overcurrent; and a display unit that displays an abnormality at the time of an overcurrent according to the output of the overcurrent detection circuit. A motor drive comprising a retriggerable one-shot multivibrator, which is connected between the display means and operates by using the output of the overcurrent detection circuit as a trigger to keep the display symbol on the display means for a certain period. apparatus.