JPS627566B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply abnormality detection device for detecting an abnormality in AC power supplied to a DC stabilized power supply device.

In a DC stabilized power supply that inputs an AC power source and outputs a stabilized DC voltage, the input AC power must be within a certain specified range in order for the DC stabilized power supply to supply a stable DC voltage. It is necessary that the voltage be maintained. However, this input power source always includes the possibility of sudden fluctuations. In response to such sudden fluctuations in the AC input power source, the DC stabilized power source detects that an abnormality has occurred in the AC input power source, and the DC power source is supplied with DC power. It is necessary to notify the load of an abnormality in the AC input power source.

The AC power supply detection methods currently implemented include the following.

A method for detecting the instantaneous value of AC input voltage...This method observes the AC input waveform or something similar, and when it deviates from a certain standard, it notifies you of an abnormality in the AC power supply.

A method for detecting the average value of AC input voltage...This method observes the value of DC voltage after rectifying and smoothing the AC input voltage, and when this value deviates from a certain standard, an abnormality in the AC power supply is reported.

Since the first method observes the instantaneous value of AC input, it has extremely fast response characteristics, but on the other hand,
It has the disadvantage that it responds even to instantaneous fluctuations in the AC input power supply that are within the operable range of the DC stabilized power supply.

In addition, the second method does not detect AC power supply abnormalities until the operating limit of the DC stabilized power supply is reached.
The drawback is that it cannot cope with instantaneous fluctuations in the AC input power supply.

The present invention makes it possible to eliminate such drawbacks of the conventional devices and to provide a power supply abnormality detection device that can select an AC power supply abnormality detection characteristic according to the characteristics of the load side that receives power from a stabilized DC power source. It is something to do.

The present invention provides a power supply abnormality detection device for detecting an abnormality in an AC power supply input to a DC stabilized power supply, including: an AC detection section that outputs a control signal when the AC power supply is abnormal; a plurality of time constant circuits that measure time for a certain period of time and output an alarm signal when the time from when the control signal is output reaches a predetermined time determined for each; and a selected one of these time constant circuits. The present invention relates to an abnormality detection device for a power source, characterized in that the present invention includes a selection section that sends out an alarm signal from one of the power sources.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows one implementation of the present invention of a DC stabilized power supply that receives AC power as input and is equipped with an AC abnormality detection mechanism that monitors the state of alternating current (hereinafter abbreviated as AC) input voltage and notifies this state. FIG. 2 is a block diagram of an example. In FIG. 1, an AC input circuit 100 that inputs an AC input 1 performs control of the AC input circuit, etc., and a rectifier circuit 101 is a circuit that rectifies and smoothes an AC voltage 2 from the AC input circuit 100. The DC output circuit 102 is a circuit that outputs the unstabilized DC voltage 6 from the rectifier circuit 101 as a desired stabilized DC voltage 4, and the configuration from the AC input circuit 100 to the DC output circuit 102 is as follows. It is similar to a conventional AC input type DC stabilized power supply.

The AC detection and notification mechanism is an AC detection circuit 103
and an alarm notification circuit 104.
The AC detection circuit 103 monitors the AC voltage 2 output from the AC input circuit 100 to the rectifier circuit 101, and generates an AC abnormality (hereinafter abbreviated as alarm) signal 3 when this value shifts outside the standard range. The alarm reporting circuit 104 converts the alarm signal 3 from the AC detection circuit 103 into a signal form required by an external device (hereinafter, the device receiving power from the main DC power supply will be abbreviated as such) and generates an alarm signal. It is sent as 5.

FIG. 2 shows a detailed block diagram of the AC detection circuit 103 of FIG. 1. In Figure 2,
The AC voltage 2 is constantly monitored by the AC detection unit 200, and when it becomes out of specification, the time constant circuit T ₀ 20
1, the control signal 11 is generated for the same T ₁ 202, . . . same T _o 203. This control signal 11 becomes false as soon as the AC input voltage returns to within the standard, and instructs the time constant circuits T ₀ 201, T ₁ 202, . . . T ₀ 203 to stop operating.

Time constant circuit T ₀ 201, T ₁ 202...T _o 20
3 sequentially sends out power alarm signals 12, 13, and 14 to the selection section after the elapse of the time specified in each time constant circuit when the control signal 11 becomes true. Time constant circuit T ₀ 201, T ₁ 202, ...T _o 203
Each time constant circuit operates in such a way that when the control signal 11 returns from true to false within the time specified for each time constant circuit, each time constant circuit is reset to its initial state.

The selection unit 204 outputs any one of the power alarm signals 12, 13, and 14 as the power alarm signal 3 to the alarm reporting circuit 104 under prespecified conditions.

Therefore, it is possible to output to the alarm reporting circuit 104 one of the power alarm signals 12 to 14 that is suitable for the characteristics of the external device to which the DC voltage 4 is supplied from the DC output circuit 102.

That is, each of the time constant circuits T ₀ 201 to Tn 203 outputs the power alarm signals 12 to 14 from the point P (the point at which an abnormality occurs in the AC input 1) shown in FIG.
Of the time T ₀ to Tn until each is output,
Less than the delay time until the DC voltage 4 falls from point P minus the minimum time during which the external device receiving the DC voltage 4 still needs to be supplied with the DC voltage 4 after receiving the alarm signal 5. , and if one of the power alarm signals 12 to 14 is selected and sent to the alarm reporting circuit 104 so as to select the closest one, the external device receives the necessary margin time T _DC (see Fig. 3, Power alarm signal 1
2 to 14, that is, the time from when the alarm signal 5 is output until the DC voltage 4 drops) can be secured.

Moreover, the time constant circuits T ₀ 201 to Tn 203 are
In the case of a momentary interruption of AC input 1 that is less than the established time To~Tn for each, the power alarm signal 12~1 is reset because it is reset when AC input 1 is restored.
4 does not occur. Therefore, by selecting the power alarm signals 12 to 14 in the selection unit 204 as described above, the external device receiving the DC voltage 4 can
The alarm signal 5 is not unnecessarily received even when the AC input 1 is interrupted for a period shorter than the AC input interruption tolerance time (instantaneous interruption time of the AC input 1 that can be tolerated by an external device).

Note that the above-mentioned "minimum time during which the external device still needs to be supplied with the DC voltage 4 after receiving the alarm signal 5" means, for example, when the external device is an information processing device, information protection processing is executed. The time required for

FIG. 3 shows the operation timing of each part when the time constant circuit _T1 is selected. The symbols of the waveforms in the figure correspond to each part in Figures 1 and 2.The alarm output from this DC power supply is output to the load after time T ₁ has passed after the AC input disconnection is detected at point P. will be notified. The value of this time T ₁ is selected according to the AC input cut-off tolerance time of the load (external device) that receives power from the DC power supply. As shown by the dotted line in FIG. 3, if the AC input interruption time is less than or equal to T ₁ , the time constant circuit T ₁ 202 will not operate, and therefore no power alarm will be issued and the external device will This prevents unnecessary processing due to power alarm notification within the AC permissible instantaneous interruption time. In the figure, T _DC indicates the margin time.

As explained above, the present invention measures time only while the AC power input to the DC stabilized power supply is abnormal, and measures the time from the time when the AC input becomes abnormal. By installing multiple time constant circuits that output alarm signals when the specified time has elapsed, and selecting one of the alarm signals, the external device supplied with DC from the DC stabilized power supply can respond to the AC input cut-off tolerance time. A power supply abnormality detection device that can give an alarm signal can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
This figure is a detailed internal block diagram of the AC detection circuit in FIG. 1, and FIG. 3 is an operation timing waveform diagram of each part in FIGS. 1 and 2. 100... AC input circuit, 101... Rectifier circuit, 1
02...DC output circuit, 103...AC detection circuit, 1
04...Alarm reporting circuit, 200...AC detection section,
201... Time constant circuit T ₀ , 202... Time constant circuit
T ₁ , 203...time constant circuit T _o , 204... selection section.

Claims (1)

[Claims] 1. In a power supply abnormality detection device that detects an abnormality in an AC power supply input to a DC stabilized power supply, an AC detection unit that outputs a control signal when the AC power supply is abnormal, and an AC detection unit that outputs a control signal only while the control signal is output. A plurality of time constant circuits that measure time and output an alarm signal when the time from the output of the control signal reaches a predetermined time, and one of the time constant circuits selected from these time constant circuits. A power supply abnormality detection device comprising: a selection unit that detects an alarm signal from one of the sources.