JPS60200725A - Power interruption detector circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a power outage detection circuit for an information processing device installed in an ordinary office.

(b) Technical Background In recent years, information processing devices have become smaller and are being installed not only in computer rooms but also in ordinary offices. When installed in a computer room, an external power supply 1, for example, a constant voltage/constant frequency power supply, is installed, and stable power is supplied to the information processing equipment from the constant voltage/constant frequency power supply, preventing power outages, instantaneous interruptions, and voltage drops. etc. will not occur. However, information processing equipment installed in offices does not have an external power source.

Commercial power sources are often used as is, and therefore, when a power outage, instantaneous interruption, voltage drop, etc. occur, information processing devices may malfunction. Therefore, a power failure detection circuit is provided to detect power failures, instantaneous interruptions, voltage drop, etc., and output a power failure detection signal to reset the device or perform interrupt processing to protect device data.

(C) Conventional technology and problems A conventional power failure detection circuit of this type will be described below.

Figure 1 shows a circuit configuration block diagram of a conventional power failure detection circuit, where 1 is a rectifier circuit and 2 is a resistor.

3 is a photocoupler, 4 is a primary side diode, 5 is a secondary side transistor, 6 is a driving transistor, 7 is a relay, 8
indicates a detection contact, a indicates an AC input terminal, and b indicates a signal output terminal.

In the figure, commercial power input from AC input terminal a is directly rectified by rectifier circuit l.

It is connected to the primary side diode 4 of the photocoupler 3 through the resistor 2, and when the input voltage is normal, the photocoupler 3 is turned on and the secondary side transistor 5 is also turned on, and the relay driving transistor 6 is turned on and the relay 7 is operated. Then, the detection contact 8 opens.

When the input from the AC input terminal a is interrupted due to a power outage or instantaneous interruption, the photocoupler 3 is turned off, the relay 7 is restored, the detection contact 8 of the relay 7 is closed, and the signal output terminal is connected to the device side (not shown).
A power outage detection signal such as an interrupt signal was being sent to the

In some cases, the voltage between the emitter and collector of the driving transistor 6 is detected without using the relay 7, and the logic level is used as a detection signal for a power outage or the like.

In this conventional power failure detection circuit, when the input voltage drops 1For example, 9 normal AC 100V power is supplied, but if for some reason the AC input terminal a
If the voltage drops to 50V, it cannot be detected. However, when the input voltage of the device's power source reaches 50V, the output decreases, causing the device to malfunction and the device data to be unprotected.

(d+) OBJECT OF THE INVENTION The present invention aims to solve the drawback of the conventional method that does not detect a drop in voltage even when the input voltage drops, resulting in the device malfunctioning and the device data being unprotected.

+11) Structure of the Invention The above object is to input an input terminal through a constant voltage diode connected in series to the primary diode side of a photocoupler,
Alternatively, the primary diode side of the photocoupler may be operated by a transistor.

A constant voltage diode is inserted between the base of the transistor and the second diode side, and an input voltage is input between the second diode side and the constant voltage diode,
The secondary transistor side of the insulated photocoupler is turned on/off by turning on/off the secondary diode side, and when the secondary transistor side is turned off, the output means is activated to send out a power failure detection signal. This is achieved by the present invention. In addition, for the purpose of improving the present invention, a charging capacitor is connected to the collector on the secondary transistor side of the photocoupler, and the secondary transistor side of the photocoupler is turned off to charge the charging capacitor, and the charging capacitor is charged. The invention is improved by the present invention, wherein a differential amplifier is activated when the voltage exceeds the reference voltage of the reference voltage source, and the output means is activated by activation of the differential amplifier to send out a power failure detection signal. In addition, for the purpose of further improving the present invention, the primary diode side of the photocoupler is operated by a transistor, a constant voltage diode is inserted between the heath of the transistor and the secondary diode side, and the secondary diode side and the primary diode side of the photocoupler are operated by a transistor. An input voltage is input from between the voltage regulator diode, a first charging capacitor is connected to the collector on the secondary transistor side of the photocoupler, and the secondary transistor side of the photocoupler is turned off to charge the first charging capacitor. and charge the first
When the charging voltage of the charging capacitor exceeds the reference voltage of the first reference voltage source, the first differential amplifier operates, and the operation of the first differential amplifier causes the second differential amplifier to invert, Inversion of the second operational amplifier discharges the second charging capacitor.

As long as the charging voltage of the second charging capacitor is lower than the reference voltage of the second reference voltage source, the third operational amplifier operates, and the operation of the third operational amplifier operates the output means, and the output means is activated. When the input voltage is restored by sending out a power outage detection signal by means.

The secondary transistor side of the photocoupler is turned on to discharge the first charging capacitor, and the charging voltage of the first charging capacitor becomes lower than the reference voltage of the first reference voltage source. the differential amplifier is inverted, and the second differential amplifier is inverted again due to the inversion of the first differential differential amplifier to charge the second charging capacitor, and charging the second charging capacitor. Further improved by the present invention, wherein the voltage becomes higher than the reference voltage of the second reference voltage source, the third operational amplifier becomes inactive, and the power failure detection signal sent from the output means is stopped. be done.

That is, in a power failure detection circuit that inputs an input voltage to the primary diode side of a photocoupler and outputs a power failure detection signal by an output means from the secondary transistor side of the photocoupler, a voltage regulator diode is connected in series to the primary diode side of the photocoupler. Alternatively, connect a transistor in series and a constant voltage diode in parallel, and also connect a charging capacitor and a differential amplifier to the secondary transistor side of the photocoupler.

By connecting two stages of charging capacitors and three stages of operational amplifiers, and configuring the output means to be activated by the output operation of each final stage to output or release a power failure detection signal, the input voltage can be prevented from instantaneous interruption. Even in the event of a power outage or voltage shortage, a power outage detection signal is reliably output, and by operating the primary diode side with a transistor, loss in the constant voltage diode can be reduced. When using a power failure detection circuit in a device that maintains an output voltage for a certain period of time, by providing a single-stage configuration of a charging capacitor and a differential amplifier on the secondary transistor side, a power failure detection signal is output after a certain delay time, and In order to release the power failure detection signal after the device is fully usable after power is restored, a certain delay time can be achieved by providing a configuration of two stages of charging capacitors and three stages of operational amplifiers on the secondary transistor side. It outputs a power outage detection signal later and releases the power outage detection signal after a certain period of time.
When a momentary interruption, power outage, or voltage shortage occurs in the input voltage, it reliably outputs a power failure detection signal and sends an interrupt signal to the device to prevent malfunction of the device.

This provides a power outage detection circuit that can protect device data and is suitable for each device configuration.

(f) Example of the Invention An example of the present invention will be described below. Figures 2 and 4
6 and 9 show circuit configuration block diagrams of the power failure detection circuit according to the present invention, and FIG.

5, 7, and 8 show voltage waveform diagrams at specified positions in each power failure detection circuit according to the present invention, where the vertical axis shows the voltage level V and the horizontal axis shows the time T. Also.

Identical objects are indicated by the same reference numerals throughout the figures.

11 in FIG. 2 indicates a constant voltage diode.

A constant voltage diode 11 is inserted in series with the primary side diode 4 of the photocoupler 3. When the input voltage is lower than the operating voltage of the voltage regulator diode 11, the voltage regulator diode 11 is canted off, and the photocoupler 3 is also cut off.
When the electric appliance 7 is restored, the detection contact 8 closes and the signal output terminal sends a power failure detection signal such as an interrupt signal to the device, thereby preventing malfunction of the device.

However, in the five-wire circuit, the constant voltage diode 11 is connected in series with the primary side diode 4 of the photocoupler 3, so the input voltage applied to the photocoupler 3 and the resistor 2 is as shown in the voltage waveform diagram shown in FIG.

The input voltage from rectifier circuit 1 is Vl, constant voltage diode 1
If the Zener voltage of 1 is VZD, it is the voltage obtained by subtracting the Zener voltage VZD from the input voltage v1 of the shaded area A.

Depending on the distortion of this input voltage waveform or the transmission rate of the photocoupler 3, it becomes impossible to drive the relay 7 on the secondary side, and the primary side diode 4 of the photocoupler 3 requires a current of at least 10 mA.

The loss due to the constant voltage diode 11 becomes large. Therefore,
Although this voltage regulator diode 11 is inserted to detect a drop in the input terminal voltage more sensitively than in the conventional circuit.

Unless sufficient power is supplied to drive the relay 7, there is no point in using the power failure detection circuit.

Therefore, as a solution to this problem, a circuit configuration according to another embodiment of the present invention shown in FIG. 4 is used. In Fig. 4, la is a rectifying element, 12 is a transistor, 1
3 is a constant voltage diode, 14 is a resistor, and transistor 12 is a transistor that drives the photocoupler 3.
By inserting a constant voltage diode 13 and a resistor 14 in series between the heath terminal of the transistor 12 and the cathode of the rectifying element 1a of the rectifier circuit 1, the current flowing through the constant voltage diode 13 becomes 1/hfe of the transistor 12. Since it can be made small, the loss of the constant voltage diode 13 is significantly reduced. Also, the voltage applied to photocoupler 3 and resistor 2 is:

This is the shaded area B in the voltage waveform diagram shown in FIG.

Even taking into account changes in the transmissibility of the photocoupler 3 over time, a sufficient current can flow. 2 Under normal conditions, the photocoupler 3 is turned on by the transistor 12 and the relay 7 is activated, and in the event of an input power outage, instantaneous interruption, or voltage drop, the photocoupler 3 is turned on. 3 is turned off, the relay 7 is restored, a power outage detection signal is sent, and a stable power outage detection port is obtained in consideration of changes in the photocoupler's transmission rate over time.

However, in the circuit according to the embodiment of the present invention shown in FIG. 4, when an input abnormality occurs, it is immediately detected. For example, if the power supply of a device that is in operation is
Assuming that the output voltage can be maintained for 00 m5 ec, if the duration of the input abnormality is 100 m5 ec or less, the device operates normally and there is no need to detect it.

Therefore, in a device having a function of holding power for a period of time including an input power outage, the circuit configuration shown in FIG. 4 alone has the disadvantage of immediately sending out a power outage detection signal.As a solution to this problem, the present invention shown in FIG. A solution can be achieved by a power failure detection circuit according to another embodiment.

Fig. 6 shows a circuit in which a circuit capable of arbitrarily changing the input voltage abnormality detection time is inserted into the secondary side of the photocoupler 3 shown in Fig. 4, 15 is a charging capacitor, 16.18
; 19.20.22 is a resistor, 17 is a differential amplifier, 21
indicates a diode. The charging capacitor 15 is a capacitor that is charged by the power supply voltage Vcc through the resistor 16 when the secondary side transistor 5 of the photocoupler 3 is turned off. A charging characteristic curve is set by the time constant of the capacitance value of the charging capacitor 15 and the resistance value of the resistor 16, and the charging characteristic curve can be arbitrarily set by arbitrarily selecting the capacitance value and the resistance value. I can do it. operational amplifier 17
The charging voltage v2 charged to the charging capacitor 15 is applied to one terminal, and the reference terminal voltage v3 generated by the voltage drop across the resistor 19 due to the resistors 18 and 19 is applied to the ten terminals.

The charging voltage v2 and the reference terminal voltage v3 are compared, and if the reference terminal voltage v3 is high, the output side becomes "H" level and the driving transistor 6 is turned on.

According to the voltage waveform diagram shown in FIG. 7, the charging voltage v2 of the charging capacitor 15 shown in FIG.
The charging voltage waveform of the charging voltage v2 decreases when PI is turned on, and the reference end of the 1-operational amplifier 17 is pre-charged.

Since the voltage is suppressed to be lower than the voltage v3, the output side of the nine-operated amplifier 17 becomes "H" level, the driving transistor 6 is turned on, and the relay 7 is operated, so that the detection contact 8 is opened.

If a power outage, instantaneous interruption, voltage drop, etc. of the input voltage occurs, the photocoupler 3 will continue to be turned off, so as shown in FIG. When the voltage increases and exceeds the reference terminal voltage v3 of differential amplifier 17, differential amplifier 1
7 is reversed and the output side becomes "L" level, the drive transistor 6 and the relay 7 are turned off, and a power failure detection signal is sent out from the signal ratio. Resistance 20. diode 21
．． The resistor 22 has hysteresis so that when the charging voltage v2 of the charging capacitor 15 reaches the detection point C, the reference terminal voltage v3 is lowered. As described above, the detection delay time at the time of input abnormality can be freely determined by the charging characteristic curve of the charging capacitor 15 and the resistor 16.

A power outage detection circuit suitable for the device can be provided.

In the power failure detection circuit shown in FIG. 6, the abnormality detection signal is immediately canceled when the input power is restored, so
If the device power supply is not completely turned on, there is a problem that the device may malfunction.

Therefore, this difficulty can be solved by a power failure detection circuit according to another embodiment of the present invention shown in FIG. In Fig. 9, 23 and 26 are operational amplifiers.

24 is a transistor, 25 is a charging capacitor, and 27, 28, and 29 are resistors. The operational amplifier 23 applies the reference terminal voltage v4 generated by the voltage drop across the resistor 28 and the resistor 29 to its child terminal, inputs the output from the first operational amplifier 17 to one terminal, and the third operational amplifier 17 becomes "H" level. If so, the output side becomes "L" level.

When the operational amplifier 17 is at "L" level, it becomes "H" level. The transistor 24 is turned on by the H'' level from the operational amplifier 23. The charging capacitor 25 discharges the charge that it had been charged when the transistor 24 is turned on, and is charged when the transistor 24 is turned off.

The operational amplifier 26 applies a reference terminal voltage v4 to one terminal.

Apply the charging voltage ν5 charged to the charging capacitor 25 to the + terminal, compare the reference terminal voltage v4 and the charging voltage v5, and if the reference terminal voltage v4 is low, the output side is "H".
In FIG. 9, when the input power supply is normal, the charging voltage v2 of the charging capacitor 15 is suppressed to below the reference terminal voltage ν3 of the operational amplifier 17 by turning on/off the photocoupler 3. Therefore, the output of the dual-operational amplifier 17 is at "H" level. Since the operational amplifier 17 is at the "H" level, the output of the operational amplifier 23 is at the "L" level. Therefore, since the transistor 24 is off, the voltage of the charging capacitor 25 is high, the output of the operational amplifier 26 is at the "■" level, and the driving transistor 6 and the relay 7 are on.

When an abnormality occurs in the input power supply, the photocoupler 3 continues to be turned off, so the potential of the charging capacitor 15 increases and the operational amplifier 1
The output of No. 7 is inverted to the "L" level, and the output of the No. 2 differential amplifier 23 is inverted to the H'' level. This turns on the transistor 24, discharging the charging capacitor 25, and causing the output of the No. 1 differential amplifier 26 to go to "L". level, the drive transistor 6 and relay 7 are turned off, the detection contact 8 is closed, and a power failure detection signal is sent from the signal output terminal.If the input power is restored here, the photocoupler 3 is turned on/off. The output of the first differential amplifier 17 that starts to turn off is inverted to "H" level, and the second differential amplifier 23 is inverted to "L" and the transistor 24 is turned off.However, the charging capacitor 25 is connected to the resistor. 27, the operational amplifier 26 does not reach the "I" level until after a certain period of time, so the relay 7 is turned on with a delay time.

As described above, the power outage detection circuit shown in FIG. 9 sends out a power outage detection signal after a certain delay time on the device side due to an abnormality in the input power supply, and after the power is restored, the power outage detection circuit according to FIG. By providing an adjustable circuit, we provide a power outage detection circuit that can reset the power outage detection signal after the device becomes completely usable. The best power outage detection circuit according to the present invention shown in FIG. 9 may be selected depending on the actual situation depending on the configuration functions of the device.

(gl Effects of the Invention As explained in detail above, in a power failure detection circuit that inputs an input voltage to the primary diode side of a photocoupler and outputs a power failure detection signal by an output means from the secondary transistor side of the photocoupler, the primary diode of the photocoupler is On the side, connect a constant voltage diode in series, or connect a transistor in series and a constant voltage diode in parallel, and on the secondary transistor side of the photocoupler, connect a charging capacitor and a differential amplifier, or a charging capacitor. According to the present invention, in which a two-stage amplifier and a differential amplifier are connected in three stages, the output means is activated by the output operation of each final stage, and a power failure detection signal is output or stopped. In case of shortage.

A power outage detection signal is reliably output immediately or after a certain delay time, and the power outage detection signal can be canceled after the device is fully usable after power is restored.
Sends an interrupt signal to the device to prevent device malfunction.
This has the effect of protecting device data.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration block diagram of a conventional power failure detection circuit, FIGS. 2, 4, 6, and 9 are circuit configuration block diagrams of a power failure detection circuit according to the present invention, and FIGS. 3 and 5. , Figure 7,
FIG. 8 shows voltage waveform diagrams at designated positions in each power failure detection circuit according to the present invention. In the drawing, ■ is a rectifier circuit, and 3 is a photocoupler. 4 is a primary side diode, and 5 is a secondary side transistor. 6 is a driving transistor, 7 is a relay, 8 is a detection contact,
11.13 is a constant voltage diode, 12.24 is a transistor, 14.16.18.19.20.22.2
7, 28, and 29 are resistors, 15.25 are charging capacitors, 17, 23, and 26 are operational amplifiers, and 21 is a diode. *, IQ rod! ;figure

Claims (1)

[Claims] +1) The input voltage is input through a constant voltage diode connected in series with the primary diode side of the photocoupler, and the -
The secondary transistor side of the insulated photocoupler is turned on/off by turning on/off the secondary diode side, and when the secondary transistor side is turned off, the output means is activated to send out a power failure detection signal. Power outage detection circuit. (2) operating the lower side of the primary diode of the photocoupler by a transistor, and inserting a constant voltage diode between the base of the transistor and the secondary diode side;
2. The power outage detection circuit according to claim 1, wherein an input voltage is input between the secondary diode side and the constant voltage diode. (3) A charging capacitor is connected to the collector on the secondary transistor side of the photocoupler, the secondary transistor side of the photocoupler is turned off to charge the charging capacitor, and the charging voltage of the charging capacitor is set to the reference voltage source. 3. The power outage detection circuit according to claim 2, wherein a differential amplifier is activated when the reference voltage exceeds the reference voltage, and the output means is activated by the activation of the differential amplifier. (4) The primary diode side of the photocoupler is operated by a transistor, and the base of the transistor and the -
A constant voltage diode is inserted between the secondary diode side, an input voltage is input between the secondary diode side and the constant voltage diode, and a first charging capacitor is connected to the collector of the secondary transistor side of the photocoupler. is connected, the secondary transistor side of the photocoupler is turned off to charge the first charging capacitor, and when the charging voltage of the first charging capacitor exceeds the reference voltage of the first reference voltage source, the one differential amplifier is activated, the activation of the first differential amplifier causes a second differential amplifier to invert, and the inversion of the second differential amplifier discharges a second charging capacitor;
As long as the charging voltage of the second charging capacitor is lower than the reference voltage of the second reference voltage source, the third operational amplifier operates, and the operation of the third operational amplifier operates the output means, and the output means is activated. A power outage detection signal is sent by the means. When the input voltage is restored, the secondary transistor side of the photocoupler is turned on to discharge the first charging capacitor, and the charging voltage of the first charging capacitor becomes equal to the reference of the first reference voltage source. The voltage is lower than the first
The differential amplifier is inverted. The inversion of the first differential amplifier causes the second differential amplifier to invert again and charge the second charging capacitor;
The charging voltage of the second charging capacitor becomes higher than the reference voltage of the second reference voltage source, the third operational amplifier is inverted and becomes inactive, and the power failure detection signal is sent from the output means. 4. The power outage detection circuit according to claim 3, wherein the power outage detection circuit is configured to release the power outage detection circuit.