JP2929333B2 - Electric cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric heater and an electric cooker for heating and cooking an object to be heated by induction heating.

[0002]

2. Description of the Related Art An electric heater or an electric cooker that heats and cooks an object to be heated such as a pan by induction heating, when a temperature of a heater or a temperature in the vicinity of the heater exceeds a predetermined temperature, a user is required. In some cases, a burn warning is issued because touching a high-temperature portion by mistake may cause burns. For example, as shown in JP-A-2-288087, a control circuit is operated irrespective of the ON / OFF state of a main switch, and when an electric heater is cut off, an ambient temperature or a temperature of a heated portion becomes a predetermined value. In some cases, the notification operation is performed until the temperature becomes lower or a predetermined time elapses.

[0003]

However, in the above-described configuration, the control circuit is energized after the user turns off the main switch even if there is no danger of burns. You are consuming.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. An ON / OFF means by a relay is provided in a line from a commercial power supply to a power supply circuit for a control circuit, and a main switch is turned on. A second relay for driving a relay by connecting a first relay drive circuit for driving the relay in parallel with an appropriate number of heating means in the case of the relay circuit and a relay drive signal from the control circuit to a power supply circuit for the control circuit; The drive circuit is connected, a main switch detection circuit for detecting the ON / OFF state of the main switch is connected in parallel with a suitable number of heating means, and after the main switch is turned off, the power supply system of the control circuit itself is cut off. After the condition is satisfied, the relay drive signal is released to shut off all power supply systems.

[0005]

With the above configuration, the main switch is turned on to drive the relay supplied to the control circuit power supply circuit.
Sometimes, the first relay drive circuit performs the operation, and even if the main switch is turned off, it is held by the second relay drive circuit in accordance with the relay drive signal from the control circuit, and the main switch is turned off.
After the FF, the condition for shutting off the power supply system of the control circuit itself is satisfied and the relay drive signal of the control circuit is released, thereby acting to shut off all power supply systems.

[0006]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a main part of an electric cooker according to an embodiment of the present invention, FIG. 2 is a circuit configuration diagram relating to the relay drive, and FIG.

In FIG. 1, a commercial power supply 1 is connected to a line on one side (hereinafter referred to as an A line) and a G
The power supply on the heating means side is constituted by the ND line, and the other line (hereinafter referred to as B line) and the GND line constitute the power supply on the control side via the a contact of the relay 4.

A first relay drive circuit 5 for driving the coil side of the relay 4 between the A line and the GND line of the commercial power supply 1, a heating means 8 (in this embodiment, a resistance heating system),
The other heating means 9 (in this embodiment, an induction heating method) and a main switch detection circuit 10 are connected in parallel.

A control circuit power supply circuit 7 is connected between the B line and the GND line of the commercial power supply 1, and the control circuit power supply circuit 7 outputs a power supply voltage of the control circuit 2 and a synchronization pulse of the commercial power supply 1. The power supply for the coil of the second relay drive circuit 6 for driving the coil side of the relay 4 is supplied.

The main switch detection circuit 10 detects the ON / OFF state of the main switch 3 and outputs the result to the control circuit 2.

The control circuit 2 includes an input key 11 for operating the heating means 8 and 9, a temperature sensor 13 for detecting a temperature near the heating means 8 and 9, and the main switch detection circuit 10.
And outputs a control signal to the notifying means 12, a relay driving signal to the second relay driving circuit 6, and a heating control signal to the heating means 8 and the heating means 9.

The notifying means 12 notifies and warns the user, and is a buzzer in this embodiment. If the temperature detected by the temperature sensor 13 is higher than a predetermined temperature at which the user may get burned, the notification unit 12 notifies the user.

In FIG. 2, a relay drive circuit 5 includes a power source transformer 501 having a primary side connected to the commercial power source 1 via a main switch 3 and a rectifier 5 connected to the secondary side thereof.
02, a smoothed transistor 503 after rectification, and a transistor 506 connected to the + power supply after rectification via a base resistor 505, and the emitter of the transistor 506 is connected to the -power supply. The coil of the relay 4 has a + power supply through a backflow prevention diode 504 and a transistor 506.
Connect the collector of

The relay drive circuit 6 includes a transistor 602
And a base pull-up resistor 601, a base resistor 604 of the transistor 605 connected to the collector of the transistor 602, and a transistor 605. The emitter of the transistor 602 is connected to the + power supply side, and the emitter of the transistor 605 is connected to the-power supply side. Connect to Further, a positive power supply and a collector of the transistor 605 are connected to the coil of the relay 4 through the backflow prevention diode 603.
A diode 401 is connected to the coil of the relay 4 in anti-parallel to the power supply. The control of the relay drive circuit 6 from the control circuit 2 is performed through the resistor 606.

The power supply circuit 7 for the control circuit is a power supply side transformer 701 connected to the commercial power supply 1 through the a contact of the relay 4.
And a rectifying element 702 connected to its secondary side, a rectified smoothing capacitor 703, and a stabilized power supply 704.
The rectified power line is connected to the relay drive circuit 6.

FIG. 3 shows the state of the main switch 3, the power supply voltages V1 and V2 of the relay drive circuits 5 and 6, the relay drive signals V3 and V4, and the a contact state of the relay 4 in chronological order.

At time T1, the main switch 3 is turned off.
When it is turned on from F, the power supply voltage V of the relay drive circuit 5
1, the relay drive signal V3 is generated, and the contact a of the relay 4 switches from OFF to ON at T2. When the relay 4 is turned on, the control circuit power supply circuit 7 is turned on, the power supply voltage V2 of the relay drive circuit 6 is increased, power is supplied to the control circuit 2, and the control of the control circuit 2 is started. Then, at T3, the control circuit 2 outputs the relay drive signal V4. However, this does not affect the state where the relay 4 is already ON.

When the user switches the main switch 3 from ON to OFF at T4, the control circuit 2 shifts to control after the main switch 3 is turned off by the output of the main switch detection circuit 10. Further, the power supply voltage V1 of the relay drive circuit 5 drops, and the relay drive signal V3 stops at T5. However, since the relay drive signal V4 is still output, the ON state of the relay 4 is continued, and the commercial power supply 1 is in a state of being connected only to the control circuit power supply circuit 7.

Here, as control after the main switch 3 is turned off, the temperature sensor 13 after using the heating means 8 and 9 is used.
It is assumed that when the input temperature is high, that is, when the user is liable to be burned by mistake, control is performed by the notifying means 12 to perform a burn warning or the like. Main switch 3 is OF
If the control circuit 2 determines at T6 that the temperature has dropped to a temperature at which the user is not likely to be burned by the input of the temperature sensor 13 at T6, there is no longer any object to be controlled by the control circuit 2, so the commercial All power supplied from the power supply 1 to the electric cooker is shut off.

Between T4 and T6 again the main switch 3
Is turned on, the circuit operation is such that the relay 4 is driven by the relay drive circuit 5, but the relay 4 has already been turned on.
There is no problem. At this time, the control circuit 2 determines from the output of the main switch detection circuit 10 that the main switch 3 has been turned on, and shifts to normal control.

In the present embodiment, the heating means 8 is of a resistance heating type and the heating means 9 is of an induction heating type. However, any one of the resistance heating type and the induction heating type, two or any combination thereof may be used. I don't care.

In this embodiment, the notifying means 12 is a buzzer. However, any means such as an indicator light, a light emitting element, a sound generating device, or the like may be used as long as it gives a notice or a warning to the user.
Two or any combination may be used.

[0023]

According to the present invention, an ON / OFF means by a relay is provided in a power supply line for supplying a power supply circuit for a control circuit.
The main switch is configured to be driven by both a first relay drive circuit that drives the relay when the main switch is turned on and a second relay drive circuit that drives the relay by a relay drive signal from the control circuit. Since the main switch detection circuit for detecting the ON / OFF state is provided, when the condition for shutting off the power supply system of the control circuit itself is satisfied after the main switch is turned off, all the power supplies of the electric cooker are determined by the control circuit itself. Can be cut off, and there is an effect of reducing wasteful power consumption when the user is not cooking.

[Brief description of the drawings]

FIG. 1 is a main part block circuit diagram of an electric cooker showing one embodiment of the present invention.

FIG. 2 is a circuit diagram of a relay driving circuit.

FIG. 3 is an operation timing chart.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Commercial power supply 2 Control circuit 3 Main switch 4 Relay 5, 6 Relay drive circuit 7 Power supply circuit for control circuit 8, 9 Heating means 10 Main switch detection circuit

Claims (1)

(57) [Claims] 1. An appropriate number of heating means (8) and (9) connected from a commercial power supply (1) via a main switch (3), and the heating means (8) and (9) are controlled. In an electric cooker comprising a control circuit (2) and a control circuit power supply circuit (7) connected to the control circuit (2), a relay is provided between the commercial power supply (1) and the control circuit power supply circuit (7). (4) is provided and the power circuit for the control circuit
(7) Relay by relay drive signal from control circuit (2)
A second relay drive circuit (6) for driving (4) is connected, and a first relay drive circuit (5) for driving the relay (4) when the main switch (3) is turned on is heated by heating means. (8), (9)
And a main switch detecting circuit (10) for detecting the ON / OFF state of the main switch (3) is connected in parallel with the heating means (8) and (9) to drive the relay (4). Is the first relay drive circuit when the main switch (3) is ON
This is performed by (5), and is held in the second relay drive circuit (6) by a relay drive signal from the control circuit (2), and after the main switch (3) is turned off, the power supply system of the control circuit (2) itself is shut off. An electric cooker in which all power supply systems are shut off by releasing a relay drive signal when a condition is satisfied.