JPS58204724A - Instantaneous power interruption detecting 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 The present invention relates to instantaneous power failure detection for air conditioners and other control circuits using a microcomputer.

FIG. 1 is a circuit diagram of a conventional instantaneous power failure detection circuit, and in FIG. 1, 1 is an AC power source. The AC power supply 1 is connected to the primary winding of the transformer 2, and the anode of the diode 3 and the cathode of the diode 40 are connected to the transformer 202.
The anode of the diode 5 and the cathode of the diode 60 are connected to the other of the secondary winding of the transformer 20. The cathodes of diodes 3 and 5 are connected to point b, and diodes 4 and 6 are connected to point 0.

The diode 80 cand is connected to point b, and the anode is connected to point a. One end of the resistor 13 is connected to point b, and the other end is connected to point fa. Connect one side of capacitor 17 to point a and the other side to 0.
one is connected to the capacitor 18 at point b and the other is connected to 0.
Connected to the dots.

Microcomputer 19FiVcc terminal to point b GN
The D terminal is connected to the 0 point, and the reset terminal is connected to the a point.

The waveform at point b in FIG. 1 and the waveform at point a are shown in FIG. 3 (Φ) and dotted line a in FIG. 3(d).

Next, the operation of the instantaneous power failure detection circuit shown in FIG. 1 will be explained. The voltage of the secondary winding of the transformer 20 is full-wave rectified by a diode bridge composed of diodes 3, 4, 5, and 6, and smoothed by a capacitor 18 to form a DC power supply, which is supplied to the microcomputer 9. There is.

1. When the AC power supply 1 is turned on at to in Fig. 3, the first
The waveform at point b in the figure gradually rises as power is supplied to the capacitor 18 and the microcomputer 9, as shown in Figure 3).

On the other hand, a current is supplied to the capacitor 7 through the resistor 13 from the voltage Fib at point a in FIG. The time constant determined by the i resistor rs13 and the capacitor 7 is selected so that the rise of the resistor rs13 is delayed.

Here, when the reset terminal of the microcomputer 9 reaches the voltage shown in (2) in FIG. 3(d), the reset is released and normal operation starts according to the microcomputer 19Vi70g.

In other words, the resistor 13 and capacitor 17 are connected so that the reset is released when the voltage at () in FIG. 3 becomes stable.
This delays the reset release time.

Since the conventional instantaneous power failure detection circuit is configured as described above, a case will be described in which, for example, the AC power supply shown in FIG. 1 experiences a one-cycle instantaneous power failure. In this Figure 3, t,
When the supply of AC power source 1 is stopped at point 1, the voltage at point b in Figure 1 begins to drop as shown in Figure 3 (b), becoming lower than voltage Vo, and at point 14, AC power source 1 returns to normal. voltage.

Similarly, the voltage at point a in Figure 1 is t, as shown in Figure 3(a).
It descends from 14 and begins to rise at 14.

Here, the microcomputer 19 will not be able to operate normally if the voltage (+) in FIG. 3 becomes less than Vo, and the program will run out of control.

On the other hand, the reset terminal of the microcomputer 19 is the third terminal.
■ In the figure, do not perform the reset operation because the following does not occur. Therefore, the microcomputer 19t'j:There is a drawback that the program returns after running out of control at the L4 point. If the microcomputer 19 goes out of control, there is a risk of destroying the load controlled by the microcomputer 19, which may cause serious damage.

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional art, and it is an object of the present invention to provide a momentary power failure detection circuit that can instantly detect a temporary power failure and reset the microcomputer to prevent the program from running out of control. purpose.

Embodiments of the instantaneous power failure detection circuit of the present invention will be described below with reference to the drawings. FIG. 2 is a circuit diagram of one embodiment.

In this figure 2, an AC power supply 1, a transformer 2, a diode bridge made up of diodes 3 to 6, and a capacitor 18
The circuit including the DC m source, the microcomputer 19, the resistor 13, and the capacitor 17 is the same as that shown in FIG. 1, but differs from FIG. 1 in the following points.

That is, the cathodes 1 of diodes 3 and 5 are connected to a connection point d, and resistors 9 and 10 are connected between this connection point d and 0.
series circuit is connected. The connection point between the resistors 9 and 10 is connected to the base of a transistor 14, and the emitter of the transistor 14 is connected to a connection point C. The collector of the transistor 14 is connected via a resistor 11 to a connection point S, and a diode is connected between this connection point S and the cathodes of diodes 3 and 5.

Connection point e between the collector of the transistor 14 and the resistor 11
is connected to the base of the transistor 15 via a resistor 12, and is connected to the connection point c via a capacitor 16.
VC connected.

The emitter of the transistor 15 is connected to the connection point C, and the collector is connected to the connection point f between the resistor 13 and the capacitor 17.

3(a) to 13(d) correspond to the connection points a, b, e, f (Z) in FIG. 2, respectively.
d) shows voltage V% on the vertical axis and time t on the horizontal axis. Vo,
V, ii voltage. FIG. 3(e) Vi shows the operation of the microcomputer, and the shaded area indicates that the operation and other operations are in a stopped state. IO+t,,tt+ls+14pt,indicate the respective times.

Next, the operation of the instantaneous power failure detection circuit of the present invention configured as described above will be explained. When AC power supply 1 is turned on, a diode composed of diodes 3, 4, 5.6
It is full-wave rectified by Dobrich, has a diode 7, and is smoothed by a capacitor 18 to generate a DC voltage at the connection point.

Since there is a connection point at the same time, the capacitor 16 has a resistor IXt.
- The transistor driven by the full-wave rectified voltage at the connection point d has a voltage of the waveform shown in FIG.
Since the capacitor 16 is turned on other than in the vicinity, the charging voltage waveform of the capacitor 16 does not rise under normal conditions as shown in Figure 3 ((°). Therefore, the transistor 15 driven by the waveform at the connection point e is also turned off. There is.

On the other hand, the capacitor 17 is charged from the connection point via the i-resistor 13, and increases as shown in FIG. 3(d) with a time constant determined by the resistor 13 and capacitor 17Vc. Connection point f
If the voltage of is less than vI, there is a micro. When the voltage at the reset terminal of microcomputer-9 reaches VI (
At time t+), the reset is released and the microcomputer 9 starts normal operation according to the program.

Here, the time 1.1 when the voltage at the second connection point f reaches ■
The constants of the resistor 13 and capacitor 7 are designed so that the time required for the voltage at the connection point S to reach the stable region is longer than the time required.

Next, a case where there is a momentary power outage of the AC power supply for one cycle from time t7 shown in FIG. 3(e) will be described.

In FIG. 2, the waveform ilt at the connection point d is shown at time t! as shown in FIG. 3(a). OVK is maintained for ~t4, and -10,000 transistor 4 is turned off.

The voltage at the connection point e in FIG.

increases with the time constant of sensor 16. When the voltage at the connection point e rises, a current flows to the base of the transistor 150 through the resistor 12, and the transistor 15 is turned on.

The voltage at the connection point f of the capacitor 17 is short-circuited when the transistor 15 is turned on (time ts) and becomes 0■. Therefore, the reset terminal of the microcomputer is O.
Execution of the program is stopped at time t3.

Next, when the AC power supply 1 is restored at time t4, the transistor 14 is turned on and the transistor 15 is turned off, so the voltage at the connection point f of the capacitor 17 increases by the time of the resistor 13 and the capacitor 17, and becomes VI The microcomputer 19 is reset and operates normally according to the program.

Like this, the microcomputer 19 stops before it goes out of control [7], and a normal reset operation is performed at the time of recovery, so the microcomputer will not go out of control.

In the embodiment shown in FIG. 2, the transistor 15 and the resistor 12 are used to short-circuit the connection point f using the voltage at the connection point C.
A similar operation can also be performed using a comparator or the like.

As described above, according to the instantaneous power failure detection circuit of the present invention,
During a power outage, the first transistor is turned off to charge the first capacitor, and when the charging pressure exceeds a predetermined level, the second capacitor is turned on. As a result, a one-hour power outage can be quickly detected and the microcomputer can be reset, allowing the microcomputer to operate normally according to the program without causing the microcomputer's program to run out of control or causing damage to the load. It can be performed.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a conventional meditating power failure detection circuit, Part 2 is a circuit diagram showing an embodiment of the instantaneous power failure detection circuit of the present invention, and Figures 3(a) to 3(e) respectively. This is an operating waveform M of the power failure detection circuit shown in FIGS. 1 and 2. 1... AC power supply, 2... Transformer, 3-7... Diode, 9-13... Resistor, 14.15... Transistor, 16-18... Capacitor, 19...
microcomputer. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - [I・+c tdi N:, +'i' (spontaneous)
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A: b; Name (60 units Ryobe Electric Corporation representative δ piece + I + f: Daibe 1 representative fig Location: East I: Yu 1 XT- Dai 111-ku Marunouchi ° 112 Oto 3 C; -5, correction Claims column and Detailed explanation of the invention column of the subject specification. 6. Contents of amendment (1) Amend the claims as shown in the attached sheet. (2) " ``The anodes of diodes 4 and 6 are'' is corrected to ``The anodes of diodes 4 and 6 are''. (3) 1 hour number'' in the 9th line of page 9 is corrected to ``time constant''. (4) Page 9 In line 11, change ``to the program'' to ``to the program''.
The microcomputer 19 corrects the program. (5) After "It can be done." in the 20th line of the 9th sentence [Also, an instantaneous power failure detection signal is applied to the reset terminal of the microcomputer 19, but the detection signal tube microcomputer 19 interrupts. The instantaneous power outage process can also be processed by the program of the microcomputer 19 by adding it to the terminal or input terminal. ” to join. 7 List of Attached Documents Claims One or more Claims AC power source, rectifier means including a first capacitor for rectifying and smoothing the voltage of this AC power source, an output voltage of the rectifier means with a predetermined time constant. A second capacitor to be charged is turned on when the AC power supply is normal, short-circuiting the second capacitor, and discharges the charge of the second capacitor, and a second capacitor is turned off when the AC power supply is interrupted. 1 transistor, a second transistor that is turned off when the potential of the second capacitor is below a predetermined value and turned on when this potential exceeds a predetermined value; and a second transistor that is charged by the output of the rectifying means when the second transistor is off; When the second transistor is turned on, a third capacitor discharges the charge, and when the charge level of the third capacitor exceeds a predetermined value, a program is executed and the third capacitor is charged due to a power outage of the AC power supply. An instantaneous power failure detection circuit equipped with a microcomputer that is reset when the power level drops below a predetermined value.

Claims (1)

[Scope of Claims] An AC power supply, a rectifier including a first capacitor that rectifies and smoothes the voltage of the AC power supply, a second capacitor that is charged at a predetermined time constant with the output voltage of the rectifier, and the AC power supply. A first transistor that is turned on when the power supply is normal, short-circuits the second capacitor, and discharges the charge of the second capacitor, and is turned off when the AC power supply is interrupted; A second transistor that is off when the potential is below a predetermined value and turned on when the potential is above a predetermined value, is charged by the output of the rectifying means when the second transistor is off, and is charged when the second transistor is turned on. A third capacitor that discharges the voltage, and when the charging level of this third capacitor is more than 1 constant, the program is executed and the power failure occurs when the charging level of the third capacitor falls below a predetermined level due to a power outage of the AC power supply. Then, Mato, who is reset, also has a microcomputer and an instantaneous Juchi circuit.