JPS59206773A - Circuit for detecting abnormality of ac power supply - Google Patents

Abstract

PURPOSE:To detect the abnormality of a power supply exceeding an allowable value by connecting a hit and power failure detecting circuit for a commercial AC power supply and a continuous reduction detecting circuit for the commercial AC power supply and sending detecting signals of both circuits to a control circuit of an apparatus through respective prescribed diodes. CONSTITUTION:The commercial AC power supply is applied to diodes D1-D4 through a transformer T and supplied with full-wave rectification. The rectified voltage is divided by resistors R1, R2 and supplied to a voltage comparator 1 to be compared with reference voltage VREF1. When the voltage VREF1 is higher than the divided voltage, a capacitor C1 is charged by a time constant C1R4, and when lower than the divided voltage, the charge of the C1 is discharged by a time constant C1R3. The voltage of the C1 is supplied to a voltage comparator 2, and when the voltage exceeds a reference voltage VREF2, hit and power failure can be detected through a D6. A full wave rectified voltage is smoothed by the D, R5, R6, and C2 and the smoothed voltage is supplied to a voltage comparator 3. When the smoothed voltage is dropped lower than a reference voltage VREF3, continuous reduction of the AC power supply can be detected through the D1.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to an AC power supply abnormality detection circuit for preventing malfunctions, failures, and even damage to equipment due to continuous drop in AC power supply for 11 hours, instantaneous power outage, or power outage. 4<In equipment that operates on a stabilized DC power supply with an input AC power supply, control the target equipment when these abnormalities are detected and set time range when an abnormality occurs. The present invention relates to an AC power supply abnormality detection circuit for causing the circuit to perform processing in the event of an abnormality.

(Prior art) With the rapid progress of electronics technology in recent years, it has become possible to strictly control electronics systems themselves.
Depending on the quality of the AC power source, such as voltage, frequency, waveform, etc., there are situations in which the performance of electronic equipment is affected. For example, in the case of a DC stabilized power supply with an AC input power supply of 100μ, the output is normally guaranteed to be 1-7 V up to 90V, but if it is less than 90μ, the molded circuit that serves as the load will become unstable, resulting in malfunctions, failures, etc. occurs.

My father, it is the west that can confirm the output in advance in the event of a momentary power outage of the AC input power supply)! The A power supply frequency period is about 0.5 to 1 1' tal.

In addition, input voltage lower than 90V and lli? longer than 0.5 cycle? Is it still possible to satisfy the output even after the time stop '44?
This has the disadvantage of cost l'A due to deterioration of efficiency and increase in the number of parts, so this is actually /7! Not only is it undesirable to do so, but there are of course limits to how much it can be done, and it is not enough to overcome the expected abnormality of the father's blood.

The conventional power supply abnormality detection circuit for this persimmon is shown in Figure 1:
L (this, every current current 1 source through the transformer 111! 9 [constant voltage down +-, shi, rectifier tie auto D
1 to 1) After rectifying the aftereffects in 4, it is smoothed with a capacitor CO to create a voltage with less ripple, and this smoothed voltage vy is connected to the negative input terminal of the comparator (voltage comparator circuit) COM. When the voltage VSM is low [that is, a drop in the commercial AC power supply voltage has occurred, the voltage VSM is the reference voltage V R'
When falling below EFO, the output E of comparator COM
The configuration is such that o becomes high L/health (High Level) and sends out a power supply abnormality signal. Therefore, the power drop detection amount h1 in the conventional X'+2'lj abnormality detection circuit. i6 only detects continuous decline, but
Detection of instantaneous drops, instantaneous power outages, power outages, etc. is not done reliably, and since this continuous drop tends to occur at the same time as an instantaneous drop, it is unclear what kind of power supply abnormality is occurring, and the detection results are extremely inaccurate. ρ, which may exceed the allowable range of the above-mentioned equipment, so there is a risk that equipment malfunctions, failures, etc. cannot be prevented.

(Objective of the invention) The object of the present invention is to The output is guaranteed within the range allowed by the device, and any abnormality in the power supply that exceeds this is detected and transmitted to the equipment control amount M<4, and control processing is performed in the event of an abnormality to prevent equipment malfunctions and failures. It is to prevent such things.

(Structure of the Invention) Therefore, in the present invention, the curved power supply voltage waveform is directly sensed in the conventional power supply conductivity continuous drop detection circuit.
Determine the time 1 deviation of the waveform that falls within the preset voltage range F1
2. When the time set as the instantaneous power outage time allowed by the device exceeds 111i [Z, the circuit that detects the instantaneous power outage and power outage and sends a power abnormality signal to the device's fl;II control circuit. Hereinafter, the present invention will be described in detail with reference to embodiments.

(Real Jjlii Example) Figure 2 shows a circuit (t14-14-
1 and 3 are waveform diagrams of each part, and the operation of this example will be explained using these drawings.

The primary side AC human power 'dL source of the transformer I'll is converted to a constant AC mains voltage on the secondary side, and the rectifier diode J
) + ~ 1) Aftermath rectification is performed by 4.

Divide this full-wave rectified voltage by dividing resistors J(, 1 and H. You can also input VREF'1 on the reference voltage j.

When the positive input voltage>negative input voltage becomes comparator 1,
Charged current flows from the stabilized power supply Vcc to the capacitor C1 through the resistor, and as shown in Figure 3, the B voltage rises in a curve determined by the time constant C1R4, and vice versa. On the input terminal (negative input voltage j), the output of the comparator 1 becomes approximately Ov, and the capacitor Ci is charged. Discharge with j constant.

That is, the human waveform in FIG. 3 is one generation higher than the reference voltage VREFi; in the range where the distance and A waveforms are missing, the comparator L/
- E1 (7J) d3 power (ri) becomes high level, starts charging capacitor C1, and starts discharging to V in a high range. If a preset reference voltage VREF2 is connected to the input terminal and the negative input terminal respectively, when the B input exceeds the reference voltage V'REF2, there will be a momentary drop in the power supply and a momentary power outage. After a power outage occurs and a predetermined period of time has elapsed, the output C of the comparator 2 becomes high level and is sent to the control circuit of the device as a power abnormality signal.

On the other hand, after the full-wave rectification described above, the diode 1) is connected to the resistor 1, and the resistor 1 is also smoothed by the capacitor C2. What happens if I input the voltage to the negative input terminal of the IF input terminal and also input the predetermined reference voltage VREF3 to the IF input terminal? ! Voltage, ) (voltage - F, that is, a continuous drop in the commercial AC power supply occurs [
When one of the 7 voltages J falls below the reference voltage Jl:VRgp3, the output 1 of the comparator 3 becomes high level (1''),
It is sent out as a power layer '7T'y f word. father,
Depending on the degree of instantaneous drop (131C), the controller 3 can be used! 1Jjj 'j4 normal signal is sent, but
1 and then sent out by comparator 2 described in iii.
Since the delay is 1 time, no damage is caused by the delay in the power supply abnormality signal. Incidentally, I)6Dz is a diode for setting the connection point to a high level when either one of the outputs of the comparator 2.3 falls to the C/F level.

Note that although a transformer is used in this embodiment, it is used in a circuit that is insulated from a commercial AC power supply and is used in a circuit that is intended to step down the voltage of a commercial AC power supply to a predetermined level, and this insulation If you do not need 1 (9), you can directly full-wave rectify the AC power supply and change the resistance division ratio.Also, even if insulation is required, you can use an optical coupling element without using a transformer. can do.

Furthermore, the comparator (voltage comparison circuit) may use a semiconductor such as a transistor, and the signal sent to the control g circuit of the device can be made low level (LOWLeVeI) by changing the combination of circuits. You can also do it.

In this song, comparator 3 is made to wait for hysteresis,
For example, an abnormality signal is sent with an AC power source of 85V, and the power source is 90V.
It is also possible to cancel the sending signal when the voltage is restored to V.

(Effects of the Invention) As explained above, the present invention provides a detection circuit for instantaneous drops, instantaneous power outages, and power failures in place of the conventional circuit for detecting only continuous drops in AC power supplies. The commercial AC power supply directly senses the pressure waveform and determines the time width of the waveform that is below a preset basic renal voltage, and determines the duration of the waveform when the voltage falls below a preset basic renal voltage. By adding a new circuit that sends a power abnormality signal to the molding control circuit when the time range exceeds the corresponding period, we can guarantee the output up to the range that can be produced in the target equipment, and also , 41
1.9. For abnormalities, detect this and use the α device: jii
4 control circuit and perform 1ljlJ frill processing in the event of an abnormality? Highly reliable electricity that makes it possible to prevent malfunctions, failures, etc.: 1. ! i'.

It has the effect of connecting the abnormality detection circuit.

'181''ii (7) ii:i'kawa'yosuiro'man.

It is a 6 part waveform diagram of implementation 1v.

T,,,,L Lance,D+~lJ7,,,Taihon-Tomi Ilc,1　q is also 71. j times IC cut 41~3
．． , comparator, VREF 4h protein F3 , , group l
Yoshitun Moon Pe■cc,,.

Regulated power supply voltage.

Claims (1)

[Claims] a full-wave rectifier circuit that converts the AC power source into direct current; a dividing circuit for this output voltage; a first voltage comparison circuit that uses this divided voltage as an input voltage and compares it with a predetermined reference voltage; At a connection point between two large and small resistors connected in series between the output terminals of the voltage comparator circuit, a capacitor connected to the output terminal via the small resistor and the output voltage of the first voltage comparator circuit are inputted to obtain a predetermined reference voltage. It has a second voltage comparator circuit that compares the output voltage of the full-wave rectifier circuit with the output V of the full-wave rectifier circuit.
! an AA voltage comparator circuit that smoothes the output voltage obtained from the LA connector through the GIO 1-'; and an AA pressure comparator circuit that manually compares the output voltage from the circuit with a predetermined reference voltage. I11@Create the continuous drop detection circuit of the power supply (θ state party 1), and set each production signal of the continuous drop detection circuit and the instantaneous power outage and power outage detection circuit of Dif to the specified value. An AC power supply abnormality detection circuit characterized by sending out a signal to a control circuit of a target device via a quiode.