JPH05240889A - Power source abnormality detector - Google Patents

Abstract

PURPOSE:To automatically detect the abnormality of power source and prevent troubles by providing a means for extracting ripples in the component of power source output and a means for detecting the excess of the ripples over a predetermined level for a predetermined time period. CONSTITUTION:When the output of a power source 21 passes an input filter, only desired ripples are extracted, amplified with an alternating current amplifier 2 and made direct current with a rectifier 3. On the other hand, the output of the amplifier 2 is shaped in pulse with a wave shaping circuit 5. In the case ripple increases due to the degradation of the power source 21, the output of the rectifier 3 exceeds the set value of a degradation level setting means 11 and the output of a comparator 4 opens a gate 6. By this, the pulse from the circuit 5 passes the gate 6 and inputs in a counter 7. If counter 7 output reaches the value set by a time setter/conincidence detection circuit 8, the circuit 8 generates a signal to drive a signal generator 9. The signal generator rings a buzzer as an alarm means and indicates a monitor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for inputting a DC voltage or an AC voltage and detecting an abnormality of a power supply in an apparatus using a DC stabilized power supply or the like.

[0002]

2. Description of the Related Art Generally, in a device that receives a DC voltage or an AC voltage as an input, a stabilized DC power supply is used to supply a stable DC voltage to each operating section and circuit section of the apparatus. This DC stabilized power supply has a rectifying portion for rectifying an AC voltage and a smoothing portion for smoothing the rectified voltage.

For example, when an AC voltage is input, only a positive voltage or a negative voltage can be obtained through a rectifier circuit, but the voltage after passing through this rectifier circuit is periodically pulsating and a DC voltage is obtained. Is far from, and a smoothing circuit is provided in order to average and smooth the pulsating wave, that is, the ripple. The smoothing circuit is provided with a capacitor to attenuate the ripple.

When the capacitor in the smoothing circuit deteriorates, the capacity decreases and the loss also increases, so that heat is generated. Therefore, due to the temperature of the power supply itself and the self-heating of the capacitor, the constituent material of the capacitor becomes a terminal part or the like. It leaks from the encapsulation part and promotes a decrease in capacity and an increase in loss. As a result, in the output of the DC stabilized power supply, the ripples gradually increase with the passage of time, and finally the capacitor completely crashes and the output voltage fluctuates greatly, causing a voltage drop.

In the past, in order to maintain the reliability of the stabilized DC power supply and not to cause the above-mentioned problems, regular inspections were performed and the deteriorated parts were replaced with new ones. Also, especially when the output of the stabilized DC power supply may have a large impact on the system, monitor the deterioration state of the parts inside the power supply device while observing the output waveform of the power supply voltage by appropriately using measuring equipment such as a synchroscope. is doing. Since the decrease in the output voltage of the power supply is a measure of the deterioration, a device or the like is used which continuously monitors the output decrease of the DC stabilized power supply and generates an abnormal signal when the output falls below a certain value.

[0006]

However, in the above-mentioned conventional method, the method of regularly inspecting and observing using a measuring instrument requires an excessive amount of labor, and the voltage drop is continuously monitored and kept constant. In the method of judging an abnormality when the value is less than the value, the power supply is in a failure state because the voltage drop is already remarkable, and the influence on the device is very large.

The present invention automatically detects a power supply abnormality,
Moreover, it is an object of the present invention to provide a power supply abnormality detection device that can know a failure of a power supply in advance and prevent a trouble before the deterioration of the power supply device adversely affects the entire system.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, a power supply abnormality detecting device of the present invention comprises means for extracting a ripple in a power supply output component, and the ripple continues for a predetermined time and is at a predetermined level or more. And means for detecting that

[0009]

In the present invention, the ripple in the power supply output component is extracted and detected, and when the extracted ripple continues to be above the predetermined level for the predetermined time, the power supply abnormality is detected. A state in which a failure is occurring can be detected in advance and a trouble can be prevented in advance, rather than a method in which the output value of the power supply itself is monitored to determine whether it is abnormal according to the level. Also, when the extracted ripple continues to exceed the specified level for a specified period of time, a power supply abnormality is detected, so ripples due to external factors such as sudden changes in load or fluctuations in the input to the power supply can be detected. It is possible to accurately notify the power supply state without considering the fluctuation as a power supply abnormality.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a power supply abnormality detection apparatus according to an embodiment of the present invention.

The inside of the broken line shows the state in which the power source 21 and the load 22 to which the voltage or current is to be supplied from the power source 21 are connected, and this portion is located outside the apparatus of the present invention.

The input filter 1 and the power supply line are connected to extract a voltage or a current from the power supply line connecting the power supply 21 and the load 22. The input will be described below as a voltage. The input filter 1 is composed of a high-pass filter, a band-pass filter, etc. so as to extract a ripple in a desired frequency region. Input filter 1
The output from is amplified through the AC amplifier 2 and input to the rectifier 3. The output from the rectifier 3 is supplied to the comparator 4. On the other hand, the signal from the AC amplifier 2 is also input to the waveform shaping circuit 5. The waveform shaping circuit 5 has a function of shaping the pulsating waveform (usually close to a sine wave) from the AC amplifier 2 into a rectangular wave. The comparator 4 compares the value from the deterioration level setting means 11 with the input from the rectifier 3. The output from the comparator 4 and the output from the waveform shaping circuit 5 are connected to the gate 6. The output signal of the gate 6 is configured to be counted by the counter 7, and the output of the counter 7 is compared with the time set by the time setter / coincidence detection circuit 8 and if they match, the time setter / coincidence The signal from the detection circuit 8 drives the signal generator 9. Further, the timer 10 is connected to the counter 7 and resets the counter 7 at a constant cycle longer than the time set by the time setter / coincidence detection circuit 8.

Next, the operation will be described. When the output of the power supply 21 passes through the input filter 1, only desired ripples are extracted. This output is a very low value of several mV when the power supply 21 is normal. In order to facilitate the analysis of this signal, the AC amplifier 2 amplifies the signal to a predetermined value, and the signal amplified by the next rectifier 3 is converted into a DC signal. Then, the comparator 4 compares the DC-converted signal with the set value from the deterioration level setting means 11, and opens the gate 6 if the signal level from the rectifier 3 is higher. The level value of the deterioration level setting means 11 may be automatically set by a ROM or the like, or may be manually set by an external panel. On the other hand, the output of the AC amplifier 2 is shaped into a rectangular wave, that is, a pulse-shaped waveform by the waveform shaping circuit 5, and is guided to the gate 6. Here, when the power supply 21 is normal, the extracted ripple is about several mV at the output stage of the input filter 1 and does not exceed the level value by the deterioration level setting means 11, so the output of the comparator 4 passes through the gate 6. Keep it closed. Therefore, since the pulse signal from the waveform shaping circuit 5 is not output from the gate 6, the counter 6 does not count.

However, when the ripple gradually increases due to the deterioration of the power source 21, the output of the rectifier 3 exceeds the set value of the deterioration level setting means 11 because it increases up to several hundred mV when passing through the input filter 1. As a result, the output of the comparator 4 acts to open the gate 6. When the gate 6 is opened, the pulse signal from the waveform shaping circuit 5 passes through the gate 6 and is input to the counter 7. When the output of the counter 7 reaches the value set by the time setter / coincidence detection circuit 8, the time setter / coincidence detection circuit 8 outputs a signal. Generate and drive the signal generator 9. The signal generator 9 is provided with means for sounding a buzzer as an alarming means, and for displaying on a monitor that the power supply is in a danger area due to deterioration. Here the time setting device
The time setting in the coincidence detection circuit 8 may be automatically set by a ROM or the like like the deterioration level setting means 11, or may be manually set by an external panel.

FIG. 2 is a time chart of the main part of the above embodiment. As shown in FIG. 2, when the ripple amplitude gradually increases due to the deterioration of the power supply 21, the output of the comparator 4 changes from the low level to the high level at a certain point.
When the output of the comparator 4 becomes high level, the gate 6 opens, so that the pulse signal from the waveform shaping circuit 5 is input to the counter 7, and as long as the output of the comparator 4 is in the high level state, the counter 6 7 will continue to count.

If the load suddenly changes or the input to the power source fluctuates, the ripple of the power source may increase for a short time. Since the counter 7 also counts at this time, external factors of the power source and internal power source It is necessary to distinguish it from that due to deterioration. Therefore, the timer 10 is provided so as to reset the counter 7 at a constant cycle that is longer than the set time of the time setter / coincidence detection circuit 8 so that ripples due to short-term fluctuations in the power supply remain in the counter 7. It is preventing.

In the above embodiments, the ripple of a predetermined level or more for a certain period is detected and this is used as a power supply deterioration prediction signal. However, a circuit for detecting a drop of the power supply voltage itself is added to the circuit of the above embodiment. In addition, a dual structure may be used to predict the deterioration of the power supply and to issue a danger signal by knowing the decrease of the power supply voltage itself to more surely prevent the system down of the main body device.

[0018]

[Other Embodiments] FIG. 3 shows another embodiment of the present invention.
The difference from the embodiment is that the timer 10 is not provided and that the output of the comparator 4 is supplied to the gate 6 as well as to the counter 7.
In the embodiment of FIG. 1, the amplitude of the ripple that occurs with the deterioration of the power supply is not expected to decrease even if the amplitude begins to increase, so the time taken to count by the counter 7 is It should be counted continuously, and if it is not, it can be determined that it is a ripple fluctuation due to an external factor of the power supply. Therefore, the timer 10 resets the value accumulated and counted in the counter 7 at a constant cycle. ..

The embodiment of FIG. 3 requires more frequent resets than the embodiment of FIG. 1, but allows for a more direct response. That is, the output signal of the comparator 4 is connected to the reset terminal of the counter 7, and the counter 7 is reset when the output of the comparator 4 becomes low level. When the output of the comparator 4 is at a high level, the counter 7 is released from the reset state, so that counting can be performed. When the pulse signal is continuously counted to a predetermined value without interruption, the power supply is abnormal. To judge.

[0020]

As is apparent from the above description, according to the present invention, it is not necessary to regularly check and observe the ripples by using a measuring instrument, so that an excessive effort is not required and the ripples in the power supply voltage are not required. Since the change in the component is monitored, it is possible to detect the abnormality of the power supply and prevent the trouble before the deterioration of the power supply device adversely affects the entire system. In addition, since the power supply abnormality is detected when the ripple continues to rise above a predetermined level for a predetermined time, fluctuations in the ripple due to external factors such as a sudden change in the load or a change in the input to the power supply can be detected. It is possible to notify the power status accurately without being considered as a power failure.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a power supply abnormality detection device of the present invention.

FIG. 2 is a time chart diagram of an embodiment of the power supply abnormality detection device of the present invention.

FIG. 3 is a block diagram of another embodiment of the power supply abnormality detection device of the present invention.

Claims (1)

[Claims] 1. A power supply abnormality detection, comprising: a means for extracting a ripple in a power supply output component; and a means for detecting that the ripple continues to be above a predetermined level for a predetermined time. apparatus.