JPH06267366A - Control device for electrical equipment - Google Patents

Abstract

(57) [Summary] [Object] The control device for an electric device of the present invention ensures that the power supply is turned off to the load even when an abnormality occurs in the control circuit. A switch signal output circuit 27 having a manually operated power switch 16 and a flip-flop 30 for inverting an output from a non-inverting output terminal Q1 when a switch signal Sa from the switch signal output circuit 27 is given. The relay drive circuit 22 is provided so as to be controlled by the AND condition between the drive signal Ss (control command) from the control circuit 20 and the output of the flip-flop 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric device having an improved switch structure for turning on / off the power of the electric device.

[0002]

2. Description of the Related Art In an electric machine, for example, a washing machine, a power switch is provided at the rear of the upper surface of the main body of the washing machine. This power switch is interposed in a power supply path from the AC power supply to the load as an electric circuit configuration. In addition, this power switch is a switch that both turns the power on and off, and has a latch mechanism that turns on the power when pushed and mechanically latches it at the pushed position. Then, the latch mechanism is released and the power is turned off.

By the way, a power switch having such a latch mechanism is manually turned on and off, and its mechanical structure is complicated. Therefore, it cannot be controlled by a control circuit including a microcomputer. is there. In particular, the washing machine has a control unit at the front of the upper surface of the washing machine main body, and this control unit section is used for centralized control and various displays, and the power switch is also required to be arranged in this control unit section. However, since the power switch has a mechanically complicated structure as described above and is provided in the power supply line, it is necessary for the control unit part that is controlled by a weak control voltage / control current. The reality was that it could not be incorporated.

As a countermeasure against this, there is one configured as shown in FIG. In this device, a relay switch 4 is interposed in an energizing circuit 3 from a commercial AC power source 1 to a load 2, and the relay driving circuit 7 is operated by operating a control circuit 6 based on an operation of a power source switch 5. The drive is controlled via the. In this case, the power switch 5 is a small switch such as a tact switch suitable for an electronic control circuit used with a weak control voltage / control current, and the switch signal of the power switch 5 is input to the control circuit 6. ing. The control circuit 6 includes a microcomputer, constantly scans the switch signal from the power switch 5, and when the switch signal is input, it controls the outputs of the output terminals P1 and P2 to drive the relay. The relay coil 8 of the circuit 7 is cut off and the relay switch 4 is turned on and off to cut off the load.

[0005]

However, in the case of FIG. 5 described above, when the microcomputer program in the control circuit 6 runs out of control due to some abnormality, the operation is continued when the load 2 should be stopped. In some cases, that is, the load may operate abnormally. In this case, even if the power switch 5 is operated, the relay switch 4 cannot be opened, that is, the power cannot be turned off and the load cannot be cut off because the program itself is out of control.

The present invention has been made in consideration of the above circumstances, and an object thereof is to control a relay switch by a control circuit so that a load is turned on and off, and an abnormality occurs in the control circuit. Even in the case of doing so, it is an object of the present invention to provide a control device for an electric device that can reliably turn off the power supply to a load and prevent an abnormal operation of the load.

[0007]

A control device for an electric device according to the present invention comprises a control circuit including a microcomputer, a relay switch interposed in a power supply path from a power supply to a load, and a relay for controlling opening / closing of the relay switch. A drive circuit, a switch signal output circuit which has a manually operated power switch and outputs a switch signal in response to the operation of the power switch, and an output from an output terminal when a switch signal from this switch signal output circuit is given Is provided, and the relay drive circuit is controlled by an AND condition between the control command from the control circuit and the output of the flip-flop (the invention of claim 1). .

In this case, the control circuit may be configured to output an auto power off signal, and the auto power off signal may be applied to the reset terminal of the flip-flop (the invention of claim 1).

[0009]

[Function] When the power switch is operated and the switch signal is output from the switch signal output circuit while the relay switch is open, the output of the flip-flop is inverted, and the relay drive circuit outputs the signal for driving the relay. Is output as. Along with this, when a control command for closing the relay switch is output from the control circuit to the relay drive circuit,
The relay drive circuit operates to close the relay switch. That is, the relay drive circuit is operated by the AND condition between the output of the flip-flop and the control command of the control circuit.

When the power supply should be turned off as in the case where the microcomputer runs away in the control circuit, the power switch is opened. The flip-flop inverts the output by the switch signal accompanying this opening, that is, the output changes to stop the relay drive. As a result, the relay drive circuit opens the relay switch regardless of the control command from the control circuit.

In this case, if the control circuit is configured to output an auto power-off signal and the auto power-off signal is applied to the reset terminal of the flip-flop, the relay switch is operated via the flip-flop during the auto power-off. Therefore, the flip-flop can be used for automatic power-off, and the configuration can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a washing machine will be described below with reference to FIGS. First, FIG. 2 shows a washing machine which is an electric device. An upper cover 12 is provided on an upper part of a washing machine main body 11, and an inlet / outlet 13 is formed in the upper cover 12. An operation panel 14 of the unit is provided. The upper cover 12 is opened and closed by a foldable lid 15.

As shown in FIG. 3, the operation panel 14 is provided with various switches, and in particular, the power switch 16 is also provided on the operation panel 14. The power switch 16 is a small switch for an electronic control circuit such as a tact switch, and is an automatic reset type.

Now, FIG. 1 shows an electric circuit configuration for a load used in this washing machine, and this circuit configuration will be described. The load 17 is connected to a commercial AC power supply 18, and a relay switch 19 is interposed in a power supply path from the power supply 18 to the load 17. On the other hand, the control circuit 20 is configured to include a microcomputer,
The drive signal Ss as a control command for controlling the relay switch 19 is output from the output terminal P1 in a pulse form. The control circuit 20 outputs a low-level auto power-off signal So from the output terminal P2 after a lapse of a certain time after the operation is completed, and further outputs a reset signal Sr from the output terminal P3 when the microcomputer starts operating when the power is turned on. It is supposed to be done.

The drive signal Ss is applied to the transistor drive circuit 21. When the pulse drive signal Ss is applied to the transistor drive circuit 21, the transistor drive circuit 21 waveform-shapes the drive signal Ss to form the relay drive circuit 22. The first transistor 23 is turned on and off. The relay drive circuit 22 includes the first transistor 23.
And the relay coil 24 and the second transistor 25,
A direct current power supply Vdd (+ 12V) for driving and GND are connected in series, and a flywheel diode 26 is connected to the relay coil 24 with the polarity shown in the figure. The relay coil 24 closes the relay switch 19 when energized and opens when the power is cut off.

The power switch 16 described above is incorporated in the switch signal output circuit 27, and the switch signal output circuit 27 will be described. The switch signal output circuit 27 is provided between the control voltage Vcc (+ 5V) and GND.
The power switch 16, the resistor 28, and the capacitor 29
Are connected in series, and the resistor 30 is connected in parallel to the resistor 28 and the capacitor 29. Then, when the power switch 16 is closed, a high-level switch signal Sa is output from the output terminal 27a (connection point between the resistor 28 and the capacitor 29) and applied to the clock terminal CK of the flip-flop 30.

The non-inverting output terminal Q1 of the flip-flop 30 is connected to the base of the second transistor 25 of the relay drive circuit 22 and also the control circuit 20.
Of the input terminal I1. The inverting output terminal Q2 is connected to the data input terminal D. The reset terminal R is connected to the output terminal 31 a of the reset signal output circuit 31. The reset signal output circuit 31 is supplied with an auto power-off signal So from the output terminal P2 of the control circuit 20 as an input and a reset signal Sr from the output terminal P3. The reset signal output circuit 31 has a high level auto power off signal So and a reset signal S, respectively.
When r is given, it is inverted and flip-flop 3
The reset terminal R of 0 is applied. The flip-flop 30 is reset when the reset terminal R changes to low level, and sets the non-inverting output terminal Q1 to low level and the inverting output terminal Q2 to high level.

Now, the operation of the above configuration will be described with reference to FIG. Now, when a power plug (not shown) is connected to a power outlet, the drive power Vdd and the control power Vcc are applied to each circuit including the control circuit 20.
Then, the high-level reset signal Sr is output from the output terminal P3 of the control circuit 20 and the output terminal P2.
Outputs a high level signal. As a result, the reset signal output circuit 31 outputs a low level signal to the reset terminal R of the flip-flop 30. Then, as shown in FIG. 4, the non-inverting output terminal Q1 is set to low level, and the inverting output terminal Q2 is set to high level (and therefore the data input terminal D is also high level).

At this time, in the switch signal output circuit 27, the power switch 16 is opened, the switch signal Sa is at the low level, and the clock terminal CK of the flip-flop 30 is also at the low level. Further, both the first transistor 23 and the second transistor 25 of the relay drive circuit 22 are off, and the relay switch 19 is open.

When the power supply to the load 17 is turned on, the power switch 16 is closed (the operation time point is indicated by T1 and the closing period is indicated by L1). Then, the switch signal Sa becomes high level,
The clock terminal CK of the flip-flop 30 changes to high level. Thus, the flip-flop 30 reads the data (high level in this case) given to the data input terminal D and outputs the high level signal from the non-inversion output terminal Q1. At the same time, the inverting output terminal Q2 changes to low level. When the output of the non-inverting output terminal Q1 becomes high level, the second transistor 25 of the relay drive circuit 22 is turned on.

Here, the control circuit 20 outputs the drive signal S as a control command from the output terminal P1 according to the operation program.
When the drive signal Ss (pulse signal of a certain frequency) is output, the transistor drive circuit 21 turns on the first transistor 23 of the relay drive circuit 22. At this time, since the second transistor 25 is on, the relay coil 24 is energized, the relay switch 19 is closed, and the load 17 is energized. When the drive signal Ss is stopped, the load 17 is also cut off.

Here, when the power is turned off, the power switch 16 is closed (the operation point is T2 in FIG. 3).
, And the closing period is indicated by L2). Then, the switch signal Sa becomes high level, and the flip-flop 3
The clock terminal CK of 0 changes to high level. Thus, the flip-flop 30 reads the data (low level in this case) given to the data input terminal D and outputs the low level signal from the non-inversion output terminal Q1. At the same time, the inverting output terminal Q2 changes to high level. When the output of the non-inverting output terminal Q1 becomes low level, the second transistor 25 of the relay drive circuit 22 is turned off. As a result, the relay drive circuit 22 is opened regardless of the operating state of the control circuit 20, the relay switch 19 is opened, and the power supply to the load 17 is turned off.

When the control circuit 20 outputs the low level auto power off signal So from the output terminal P2 by the auto power off function, the reset terminal R of the flip-flop 30 becomes high level. This resets the flip-flop 30 and changes the output of the non-inverting output terminal Q1 to low level. With this, the relay drive circuit 2
2 is opened and the relay switch 19 is opened, so that the power supply to the load 17 is turned off.

When the program of the control circuit 20 runs out of control, the output of the drive signal Ss may not be stopped and the load 17 may remain energized. In such a case, the user operates the power switch 16 by recognizing the situation that the driving is not completed forever. Then, as described above, by opening the power switch 16, the second transistor 25 of the relay drive circuit 22 is turned off via the flip-flop 30, so that the relay drive circuit 22 is opened regardless of the operation of the control circuit 20. Then, the relay switch 19 is opened, and the power supply to the load 17 is accordingly turned off.

As described above, according to this embodiment, the switch signal output circuit 2 having the manually operated power switch 16 is provided.
7 and a flip-flop 30 that inverts the output from the output terminal Q1 when the switch signal Sa from the switch signal output circuit 27 is provided, and the relay drive circuit 22 is provided.
Is a drive signal Ss (control command) from the control circuit 20.
Since the control is performed according to the AND condition between the output of the flip-flop 30 and the output of the flip-flop 30, the power can be surely turned off even when an abnormality occurs in the control circuit 20, and the abnormal operation of the load 17 can be prevented.

In particular, according to this embodiment, the control circuit 20 is configured to output the auto power off signal So, and the auto power off signal So is applied to the reset terminal R of the flip-flop 30 via the reset signal output circuit 31. Since the configuration is adopted, the relay switch 19 can be opened by using the flip-flop 30 at the time of automatic power-off, that is, the flip-flop 30 can be used for the automatic power-off, and the configuration can be simplified. You can Although the present invention is applied to the washing machine in the above-described embodiments, the present invention can be widely applied to other electric appliances in general.

[0027]

As is apparent from the above description, the present invention can obtain the following effects. According to the invention of claim 1, a switch signal output circuit which has a manually operated power switch and outputs a switch signal in response to an operation of the power switch, and a switch signal from the switch signal output circuit are provided. A flip-flop for inverting the output from the output terminal is provided, and the relay drive circuit is controlled by the AND condition between the control command from the control circuit and the output of the flip-flop. When an abnormality occurs in the control circuit However, it is possible to surely turn off the power supply by operating the power supply switch, and thus it is possible to prevent the abnormal operation of the load.

According to the second aspect of the present invention, the control circuit is configured to output the auto power off signal, and the auto power off signal is applied to the reset terminal of the flip flop. Therefore, it has an excellent effect that it can be used also for the purpose of simplifying the configuration.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view of a washing machine

FIG. 3 is a front view of an operation panel

FIG. 4 is a diagram showing an operation state of each part.

FIG. 5 is an electric circuit diagram showing a conventional example.

[Explanation of symbols]

11 is a washing machine main body, 14 is an operation panel, 16 is a power switch, 17 is a load, 18 is a power supply, 19 is a relay switch, 20 is a control circuit, 22 is a relay drive circuit, 23 is a first transistor, and 24 is a relay. A coil, 25 is a second transistor, 27 is a switch signal output circuit, and 30 is a flip-flop.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Makino 4-21, Yoshihara-cho, Nishi-ku, Nagoya City Toshiba Abu E-E Co., Ltd. Nagoya Office

Claims (2)

[Claims] 1. A control circuit including a microcomputer, a relay switch interposed in a power supply path from a power source to a load, a relay drive circuit for controlling opening / closing of the relay switch, and a manually operated power switch. A switch signal output circuit that outputs a switch signal according to the operation of the power switch, and a flip-flop that inverts the output from the output terminal when the switch signal from the switch signal output circuit is provided are provided, and the relay drive circuit is provided. A control device for an electric device, characterized in that control is performed according to an AND condition between a control command from the control circuit and an output of the flip-flop. 2. The electric device according to claim 1, wherein the control circuit is configured to output an auto power off signal, and the auto power off signal is applied to a reset terminal of a flip-flop. Control device.