KR19980057927A - Microwave Cooking Start Control Circuit - Google Patents

Abstract

The present invention relates to a cooking start control circuit of a microwave oven, the microcomputer 34 outputting a magnetron driving control signal as the contact point of the cooking start button 26 is turned on, and the human body contact to the cooking start button 26. The human body detecting unit 40 for outputting a signal according to whether or not, and the magnetron driving unit 42 for driving the magnetron based on the magnetron driving control signal from the microcomputer 34 and the signal from the human body sensing unit 40. It is configured to provide a cooking start control circuit of the microwave oven to operate the microwave only by pressing the cooking start button, thereby preventing the malfunction due to external influence in advance.

Description

Microwave Cooking Start Control Circuit

The present invention relates to a cooking start control circuit of a microwave oven, and more particularly, to a cooking start control circuit of a microwave oven, in which a cooking operation is performed only by pressing a cooking start key of a microwave oven.

In general, an example of a cooking utensil is a microwave oven (microwave oven), which is different from cooking utensils using heat conduction heating methods such as briquettes and gas tables and cooking utensils using heat radiation heating methods such as electric ovens. The high-frequency electricity is applied to a microwave oscillating tube called magnetron to quickly cook food placed on a turntable (or tray).

As shown in FIG. 1, the conventional microwave oven includes a rotating dish 1 for placing food to be cooked and a rotating ring 2 installed in an annular shape on the bottom of the rotating dish 1. And a door 4 for preventing the external emission of electromagnetic waves generated by cooking in the cooking chamber 3, and a plurality of buttons for inputting the microwave oven according to a user's preference. The operation panel 5 or the like.

In addition, a door lock safety device 4a is installed on one inner surface of the door 4 to fix the door 4 to the main body, and the central portion of the door 4 can see the cooking state. 4b, an electromagnetic wave absorber 4c for preventing leakage of electromagnetic waves is attached to the inner side of the door (i.e., the portion which comes into contact with the main body).

Meanwhile, as shown in FIG. 2, the operation panel 5 includes a display unit 10 in which a function display of a microwave oven is displayed in Korean, a time / weight adjustment knob 12 for inputting time / weight in a rotating manner, Clock setting button (14) used when setting or modifying the time, 12-hour reservation function for automatic and manual cooking are all reserved reservation button (16) to easily enjoy the desired dish at the desired time, the desired dish Auto cooking menu display plate (18) with automatic cooking menu for selection, cooking strength / weak in manual cooking, cooking adjustment strong / weak button (20) used for fine adjustment of cooking status in automatic cooking, thawing when the weight of sea animal is set Automatic thawing button 22 to judge the time by the microwave itself to thaw, automatic cooking selection plate 24 to select the desired dish from a plurality of cooking menu, cooking content input after the end The cooking start button 26 used for the work, the cancel button 28 used when the button is canceled during cooking or when cooking is canceled, and two kinds of dishes can be memorized according to the user's taste in addition to the automatic cooking. In addition, the storage button 30 for performing arbitrary cooking with one touch, and the door opening button 32 for designating the opening of the door are provided.

The cooking operation of the general microwave oven configured as described above is as follows.

Place the food on the rotating dish 1 of the cooking chamber 3, close the door 4 completely, and set the desired cooking menu, time and output (cooking heating temperature) using the buttons on the operation panel 5 to cook. When the start command is input, the rotating dish 1 rotates under the control of the microcomputer (not shown), and at the same time, the food in the cooking chamber 3 is cooked by the ultra-high frequency from the internal magnetron (not shown).

By the way, although the above-mentioned conventional microwave oven should be operated only when the operator presses a key (for example, a cooking start key) of the operation panel 5, for example, the static electricity of the human body has been inputted through the keypad or a part of the lightning strikes. The microcomputer malfunctioned even when the cooking start button 26 was not pressed due to an external influence such as flowing into the internal circuit along the power line. In this case, since the magnetron is abnormally driven even when the cooking chamber is under no load, there is a risk of fire, and a problem of shortening the service life of internal parts is generated.

Accordingly, the present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a cooking start control circuit of a microwave oven, in which a cooking operation is performed only by pressing a cooking start button to prevent a malfunction due to external influences. have.

In order to achieve the above object, the present invention provides a microcomputer 34 for outputting a magnetron driving control signal as the contact point of the cooking start button 26 is turned on, and a signal according to whether the human body contacts the cooking start button 26. And a magnetron driver 42 for driving the magnetron based on the magnetron drive control signal from the microcomputer 34 and the signal from the human body detector 40. do.

1 is a view showing the appearance of a typical microwave oven,

2 is a view showing an example of the configuration of the operation panel shown in FIG.

3 is a cooking start control circuit diagram of a microwave oven according to a preferred embodiment of the present invention;

4 is a view showing an installation example of the human body sensing unit shown in FIG.

5 is a view for explaining the operation of the human body sensing unit shown in FIG.

〈Description of the symbols for the main parts of the drawings〉

1: rotating plate 2: rotating ring

3: kitchen 4: door

5: operation panel 10: display panel

12: time / weight knob 14: clock adjustment button

16: Reserve Button 18: Auto Cooking Menu Display Board

20: Cooking control strong / weak button 22: Auto thawing button

24: automatic cooking selection plate 26: cooking start button

28: cancel button 30: memory button

32: door open button 34: microcomputer

36: fan relay 38: switching element for fan relay driving

40: human body detection unit 42: magnetron drive unit

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a cooking start control circuit diagram of a microwave oven according to a preferred embodiment of the present invention. The same components as those described in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The embodiment of the present invention controls the operation of the entire apparatus according to the key input signal from the operation panel 5 equipped with the cooking start button 26, and in particular, as the contact point of the cooking start button 26 is turned on, the fan relay ( A microcomputer 34 which not only conducts a switching element 38 (e.g., an NPN transistor) to output 36, but also outputs a magnetron drive control signal (e.g., a signal of a high level), and from the microcomputer 34; The magnetron driving unit 42 for driving the magnetron (not shown) only when the magnetron driving control signal (for example, high level signal) and the human body detection signal (for example, high level signal) from the human body sensing unit 40 are input at the same time. It is installed inside the cooking start button 26 to sense that the operator's body part (for example, a finger) is in contact with the cooking start button 26, and applies a signal according to whether the detection to the magnetron driving unit 42 It consists of a human body sensing unit (40).

In addition, the human body detecting unit 40 is installed on both sides of the projecting portions of the lower terminal 26a among the lower terminal 26a and the upper terminal 26b constituting the cooking start button 26, as shown in FIG. An infrared LED as the light emitting element 40a and a phototransistor as the light receiving element 40b for receiving light from the light emitting element 40a. In addition, the central portion K of the upper terminal 26b positioned above the light emitting device 40a and the light receiving device 40b is made of a transparent material that is easy to transmit light.

On the other hand, the magnetron driver 42 has a base connected to the magnetron drive control signal output terminal P2 of the microcomputer 34 via a resistor R2 and a collector is connected to one side of the magnetron relay 44 so that the microcomputer 34 Transistor as a switching element 46 which is conducted by a magnetron drive control signal from the photovoltaic device), a cathode is connected to the collector of the switching element 38, and a gate is a phototransistor as the light receiving element 40b via a resistor R4. A thyristor as the switching element 48 connected between the emitter of the 40b and the resistor R5 and turned on / off in accordance with the current inflow to this gate, and the switching element 48 via the base via the resistor R3. Is connected to the anode of the thyristor, the collector is connected to the other side of the magnetron relay 44, and the emitter is connected to a power supply terminal (e.g., a power supply of about 12V), and the switching element 48 is turned on. It is composed of a transistor as a switching element (50).

In addition, reference numerals D1, D2, D3, and D4 are diodes used to prevent short between grids when different grid keys are pressed at the same time.

Next, the operation of the cooking start control circuit of the microwave oven according to the embodiment of the present invention configured as described above is as follows.

When the operator presses the cooking start button 26 on the operation panel 5 (see FIG. 5), the contact of this cooking start button 26 is turned on and this contact on signal is input port P1 of the microcomputer 34. As a result, the microcomputer 34 outputs a high level signal through the output terminal P3 so that the switching element 38 is turned on to activate the fan relay 36. Subsequently, the microcomputer 34 outputs a high level signal through the magnetron driving control signal output terminal P2.

On the other hand, since the operator presses the cooking start button 26 when such an operation is performed, the light receiving element 40b constituting the human body detecting unit 40 is turned on to receive light from the light emitting element 40a. As a result, current flows into the gate of the thyristor 48 in the magnetron driver 42.

As the thyristor 48 is turned on, the switching element 50 in the magnetron driving unit 42 is turned on to activate the magnetron relay 44, so that the magnetron is driven to cook.

Thereafter, when the cooking is completed, the microcomputer 34 outputs a low level signal through the output terminal P3 and then outputs a low level signal through the magnetron driving control signal output terminal P2. Accordingly, the switching element 38 is turned off to turn off the thyristor 48 that has been on, and the switching elements 46 and 50 are also turned off, and the magnetron relay 44 is also deactivated, thereby driving the magnetron. Is stopped.

On the other hand, the present invention is not limited only to the above-described embodiments, but may be modified and modified without departing from the scope of the present invention.

According to the present invention as described above, because the microwave oven is operated only by pressing the cooking start button, it is possible to prevent the malfunction due to external influence in advance.

Claims (8)

Microcomputer 34 for outputting the magnetron drive control signal as the contact of the cooking start button 26 is turned on, Human body detecting unit 40 for outputting a signal according to whether the human body contact to the cooking start button 26, And a magnetron driving unit (42) for driving the magnetron based on the magnetron driving control signal from the microcomputer (34) and the signal from the human body detecting unit (40). 2. The cooking start control circuit according to claim 1, wherein the human body detecting unit (40) is installed in the cooking start button (26). 3. The cooking start control circuit according to claim 2, wherein the human body detecting unit (40) comprises a light emitting element (40a) and a light receiving element (40b). 4. The cooking start control circuit according to claim 3, wherein the light emitting element (40a) is an infrared LED. 4. The cooking start control circuit according to claim 3, wherein said light receiving element (40b) is a phototransistor for receiving light from said light emitting element (40a). The switching device of claim 1, wherein the magnetron driver 42 is connected to one side of the magnetron drive control signal output terminal P2 and the magnetron relay 44 of the microcomputer 34 and turned on by the magnetron drive control signal. 46 and a switching element 48 that is turned on / off in response to a signal from the human body detecting unit 40 and the other side of the switching element 48 and the magnetron relay 44 to be connected to the switching element 48. Cooking start control circuit of the microwave, characterized in that consisting of a switching element 50 is turned on as it is turned on. 7. The cooking start control circuit according to claim 6, wherein the switching element (46) and the switching element (50) are transistors having opposite polarities. 7. The cooking start control circuit according to claim 6, wherein the switching element (48) is a thyristor (SCR).