JPS6289420A - Instantaneous voltage drop detector - 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] Industrial Field of Application The present invention is applied to a control circuit consisting of a microcomputer, etc. that uses a zero volt pulse (hereinafter referred to as zvP) generated when the input AC power supply voltage crosses zero volt as a clock pulse. This is a device that detects instantaneous voltage drops to ensure normal operation of microcontrollers, etc., by controlling the power supply voltage by turning off the load in the event of a momentary drop in power supply voltage or a momentary power outage. be.

2. Description of the Related Art A conventional zero volt pulse detection circuit will be described with reference to FIG. A voltage obtained by rectifying the tributary voltage in both waves is applied to the A Qi terminal in Fig. 6C, divided by resistors R1 and R2, and applied to the base of transistor Q. forward voltage vb. When the voltage becomes 2, the transistor Q becomes conductive and the collector voltage becomes zero. 1 Also, the base voltage is V
Wow. In the following cases, the transistor Q is turned off and the collector voltage becomes vDD of the power supply room 1F.

When a momentary power failure occurs, no voltage is applied to the base of the transistor Q, the transistor Q is turned off, and the collector voltage becomes the power supply voltage vDD. This voltage waveform is shown in Figure 6a,
1]. a is the IR pressure waveform at point A in FIG. 6C, and b is the voltage waveform at point B in FIG.

Problems to be Solved by the Invention With such conventional circuits, it is possible to detect when the power supply voltage drops by 100 degrees, but it is not possible to detect when the electric power fE drops by, for example, 75 degrees or 60%. This instantaneous voltage drop often occurs when other devices are connected to the same power source because a large transient current flows when the other devices are turned on.

The present invention also detects an instantaneous voltage drop in the -1st era,
The object of the present invention is to provide an instantaneous voltage drop detection device that secures power supply voltage.

Means to Solve the Problem In the conventional zero-volt pulse generation circuit, the voltage obtained by rectifying the power supply voltage in both waves is divided by a resistor, and the divided voltage is applied to the base of the transistor to cause the transistor to switch.
1 P! However, when the power supply voltage is high, the time the transistor turns on is short and the time it turns off is short (
), and therefore the ZVP pulse width becomes shorter. If the power supply voltage is low, 11, and vice versa, the zvP pulse width C
j: It gets longer.

Therefore, in the first invention, by measuring the pulse width of this ZVP, when the pulse width becomes longer than the specified time,
It is determined that an instantaneous power outage or C1, 1 ↑ special electric power has occurred (~, this solves the conventional problems.

In the second invention, the double-wave rectified voltage of the power supply is compared with the standard voltage (-7, and after the comparison, the 1/ζ signal is
Momentary power outage or t, 1, after detection 1~ after a specified time
The purpose is to determine whether an instantaneous voltage low F occurs.

Operation The present invention has the above-mentioned two configurations, so that when the instantaneous voltage drops in the power supply room Y1 (76% or 60% drop, etc.),
- If there is residual voltage) or instantaneous power outage (100% drop), control such as turning off the load, etc.
When the power supply load of one control circuit is lightened to 1 or more, a drop in the power supply voltage can be suppressed and normal operation of the circuit can be maintained.

Embodiment FIG. 1 is a block diagram showing an embodiment of the instantaneous voltage drop detection circuit of the present invention. In FIG. 1, reference numeral 1 denotes a zero-volt pulse generating circuit that generates a pulse when the input AC power supply voltage crosses zero volts, and is composed of a transistor Q and resistors R1 to R3.

2 is a timer circuit that starts operating as soon as ZvP occurs, stops operating as soon as ZvP becomes zero, and determines the ZVP pulse width i++; 3 determines whether or not the ZvP pulse width exceeds a specified time. , a determination circuit that outputs a signal when the pulse width of ZvP is longer than a specified time, and 4 a load control circuit that receives a signal from the determination circuit 3 and controls such as turning off the load.

FIG. 2 shows a circuit example and voltage waveforms of the above invention. 6th ・
, A voltage obtained by rectifying the power supply voltage in both waves is applied to point A in Figure 2, C. The double-wave rectified voltage is divided by resistor 1 (1, R2) and applied to the base of transistor Q.
[: The waveform is shown in a of FIG. 2, and the collector voltage waveform of the transistor Q corresponding to the waveform of a is shown in FIG.

The voltage in Figure 2a is the on/off level of transistor Q 7
When the voltage is above, the transistor Q is turned on, and when the voltage is below v, the transistor Qi, j is turned off. The voltage drops at the fourth wave of the double-wave rectified waveform a, and at this time the ZvP pulse width becomes longer.

In Figure 2, t is the pulse width of zvP, tl is when the power supply voltage is normal, t2 is when the power supply voltage has decreased, and Zv
By measuring the pulse width t of P, it can be determined that the power supply voltage has decreased.

In Figure 2C, Zv created by zero volt pulse generation circuit 1
The pulse width of P is measured by the timer circuit 2, and the determination circuit 3 determines whether the pulse width of ZvP is longer than the standard time.The output voltage is applied to the load control circuit 4, and when the voltage decreases, the This is to ensure the power supply voltage by performing controls such as turning off the power supply.

An embodiment of the second invention is shown in FIG.

13 in FIG. 3, 1 is the same zero volt pulse generation circuit as shown in FIG. The timer circuit 6 compares the double-wave rectified voltage with the standard Ichikawa voltage 1~, and is a level detection circuit that outputs a signal when the double-wave rectified voltage E+= is below the reference voltage, and includes a comparator IC and a resistor R4~
Consists of R7. 3 is a determination circuit that detects whether the output voltage of the level detection circuit 5 is high level or low level at the time of output of the timer circuit 2, and determines whether a drop in the power supply box fF has occurred. When it is determined that there is an instantaneous voltage drop, a signal is output] 2, and the load control circuit 4 is driven to perform load control such as turning off the load.

FIG. 4 shows an example of an implemented circuit and voltage waveforms. Figure 4 d shows the power supply double-wave rectified voltage waveform at point A in the circuit diagram d, where the '1tIF level v1 is the switching level of the zero volt pulse generation circuit 1, and when v1 or more -1-, the transistor Q is turned on. (2) When the value is 1 or less, transistor Q is turned off. subordinate
), the collector voltage waveform of transistor Q becomes as shown in FIG. 4C.

The v2 level in FIG. 4a is determined by the level detection circuit 5 in FIG. 4d.
When the voltage and voltage at point A, which is the switching level of O, is level 72 or higher as shown in Figure 4, the output of the IC is low, ■
When the value is 2 or less, the output of the IC is at -.level.

In FIG. 4d, the timer circuit 2f) starts operating at the same time as ZVP occurs, outputs an output after a certain period of time, and checks the output of the level detection circuit 5 when the timer circuit 2 outputs.

At this time, when the output of the level detection circuit 6 is low level, it can be determined that the operation is normal, and when it is high level, it can be determined that the voltage is decreasing.

When the voltage decreases/f'II becomes constant, K kJ:, Judgment 1 []) Outputs a signal from path 3 L7, drives load control 1 circuit 4 7, turns off the load, etc. Take control.

In addition, in the invention of FIG. 2, the time width t of CJ:,zvP
In the invention shown in FIG. 4, setting the level limit value of the level detection circuit S at
ゝ-・ Standard level V. By setting f, it is possible to arbitrarily set the lowering level of the detection power supply and to detect and take countermeasures against instantaneous voltage drops.

Effects of the Invention As described above, according to the present invention, with a simple circuit configuration, the power supply can be protected, whereas the conventional power supply heavy duty could only protect against 100-line power outages (and only instantaneous power outages). It is extremely useful because it can protect not only against a 100% state in which the voltage drops completely, but also against an instantaneous voltage drop in which the power supply voltage drops.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the circuit of the instantaneous voltage drop detection device in the first embodiment of the present invention, FIG. 2 is the same circuit and voltage waveform diagram, and FIG. 3 is the instantaneous voltage drop detection device in the second embodiment of the present invention. FIG. 4 is a block diagram showing a circuit of a voltage drop detection device, FIG. 4 is a diagram of the same circuit and voltage waveforms, and FIG. 6 is a diagram of a conventional instantaneous voltage stop detection circuit and voltage waveforms. 1... Zero volt pulse generation circuit, 2... Old timer 1 J path, 3... Judgment circuit, 4...
- Load control circuit 6...Belt detection circuit. Figure 1 Figure 2 Figure 4 Figure 5 Procedural amendment 1lfJ Japanese G 1 year J pl l Q Day 2 Name of the invention Instantaneous voltage drop detection device 3 Person who makes the correction (Relationship with '1! 11゛ Application Address: 1, Oaza Yaman, Kadoma City, Osaka Prefecture (
') 06 Address Name (582) Matsushita Electric Industrial Co., Ltd. Representative Akio Tanii 4 Agent 571 Address 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric (
Company) Sangyo Co., Ltd. 6 Contents of amendment (1) Correct and replace "clock pulse" in line 7 of page 2 of the specification with "reference pulse". (2) "tributary" in line 15 of page 2 will be corrected to "alternating current". (3) Correct "belt detection circuit" on page 9, line 20 to "level detection circuit".

Claims (2)

[Claims] (1) A zero-volt pulse generation circuit that generates a pulse when the input AC power supply voltage crosses zero volts, a timer circuit that starts operating at the same time as the pulse generation and measures the time width of the zero-volt pulse, and a timer circuit that measures the time width of the zero-volt pulse. An instantaneous voltage drop detection device that has a determination circuit that determines whether the time is longer than a specified time, and a load control circuit that controls a load using an output signal of the determination circuit. (2) A zero-volt pulse generation circuit that generates a pulse when the input AC power supply voltage crosses zero volts, a timer circuit that starts operating at the same time as the pulse is generated, and outputs a signal after a specified time, and the input AC power supply voltage is constant. A level detection circuit outputs a signal when the voltage drops below , a determination circuit determines whether the output signal of the level detection circuit is high or low when the timer circuit outputs, and the load is controlled by the output signal of the determination circuit. An instantaneous voltage drop detection device having a load control circuit.