JP2506716B2 - High frequency heating equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency heating device, which is capable of preventing a fire or a danger of harming a user due to a failure of a control circuit such as a microcomputer. It is about.

2. Description of the Related Art Generally, a high frequency heater with an oven controls a plurality of heating heat sources such as a heater and a microwave oven. In this case, as shown in FIG. 2, in the microwave oven, the contents input from the switches SW1 to SW4 are input to the microcomputer 4, and when the heating becomes possible, the signal of O ₁ is output (in this case, the microcomputer 4 The output voltage of is 9V), and a voltage is applied to the emitter of the transistor Q4. Next, when the microwave oven user presses the START key, point A becomes 9V and transistor Q6 turns on through diode D3.
And whereby the base is pulled to OV transistor Q ₄ of the transistor Q4 is turned ON. That is, the transistor Q ₄ and the transistor Q ₆ form a safety circuit section that maintains circuit safety. When the transistor Q4 turns on, the collector of the transistor Q4 becomes approximately 9V, so the transistor Q6 continues to turn on even when the START key is released. Also, ST
When ART key is pressed, input terminal K through diode D2
Since the signal is input to 1, microcomputer 4
Outputs the output terminal O ₂ as if the START key was pressed, so that the transistor Q5 turns on. At this time, the transistor Q6 is on, so the contact of relay 5 closes,
The microwave turns on. That is, the transistor Q ₅ drives the relay 5. Towards the heater load of the oven, enter the contents input from SW1~SW4 the microcomputer § 4, is output from the output terminal O ₃ as the START key is input, the relay 6 of the heater is turned ON.

The problem to be solved by the invention is that when the heater is controlled as described above, the port of the output terminal O ₃ of the microcomputer 4 breaks down and turns on.
Left on or START at input terminal K1 due to noise
When a key is pressed, the output terminal O ₃ is output and the heater relay 6 is turned on, resulting in a very dangerous state.

The present invention solves such a conventional problem, and provides an excellent high-frequency heating device that does not enter a dangerous state even when a control unit such as the microcomputer 4 fails.

Means for Solving Problems The high-frequency heating device of the present invention, even when outputting the heater,
When input to the microcomputer from the operation unit (switches SW1 to SW4), the signal obtained by ANDing the signal output from the microcomputer and the signal from the operation unit (START key) and the START key are input to the microcomputer. At that time, the logical product of the signals output from the microcomputer is calculated and the heater is output.

Effect The high-frequency heating device of the present invention, when using a plurality of heating heat sources, by providing a safety circuit for all relay control units that control the heating heat sources, in a failure of a control circuit such as a microcomputer, a dangerous state It does not become.

Example Hereinafter, a high-frequency heating apparatus according to an example of the present invention will be described with reference to the drawings.

As shown in FIG. 1, when the content input from the switches SW1 to SW4 to the microcomputer 1 is a microwave oven, the relay 2 is controlled by the conventional method. Switch SW
When the contents input from 1 to SW4 control the heater,
Output the signal from output terminal O _{1 while} the heater can be heated,
A voltage is applied to the emitter of the transistor Q4. Then STAR
When the T key is pressed, the point A becomes 9V through the diode D3 and the transistor Q6 is turned on, whereby the base of the transistor Q4 is pulled to OV and the transistor Q4 is turned on. That is, this portion corresponds to the safety circuit portion as in the conventional example.
After that, even if the START key is released, the transistor Q6 continues to turn on because the collector of the transistor Q4 is approximately 9V. Also, the START key is the microcomputer 1
Is input to the output terminal O ₃ is output transistor Q7
Turns ON. At this time, since the transistor Q6 is turned on, the contact of the relay 3 is closed and the heater is turned on. That is, the transistor Q ₆ corresponds to a relay driving unit that drives the relay 3.

By doing this, when turning on the heater, the output terminal
Only when there is an output of O ₁ , the START key is input to the microcomputer 1, and there is an output of the output terminal O ₃ . The same applies to the case of a microwave oven, where there is output from the output terminal O ₁ , the START key is input to the microcomputer,
Turns on when there is output from output terminal O ₂ . In this way, it is possible to prevent entering a dangerous state.

Effects of the Invention As described above, in the high-frequency heating device of the present invention, when controlling a plurality of heating heat sources, since a safety circuit is provided in all relay control units, a failure of the control unit causes a dangerous state. It can prevent things, is highly safe, and is extremely advantageous in practical use.

Further, in providing a safety circuit for a plurality of heating heat sources, the safety can be obtained without increasing the number of parts and the like and increasing the cost as compared with the conventional circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a relay control section of a high frequency heating apparatus according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a relay control section of a conventional high frequency heating apparatus. 1 ... Microcomputer, 2 ... Relay (microwave oven), 3 ... Relay (heater).

Claims (1)

(57) [Claims] 1. A plurality of heating heat sources for heating cooked food, and a microcomputer for controlling the plurality of heating heat sources,
An operation unit for inputting an instruction as to which heat source of the plurality of heating heat sources is to be used and an instruction for starting heating, a relay control unit provided corresponding to each of the heating heat sources, the relay control unit and the micro. A relay drive unit provided between the computer and a logic of a signal output from the microcomputer when a heating source is selected by the operation unit and a signal output when an instruction to start heating of the operation unit is issued. A high frequency heating device comprising a safety circuit unit that is turned on by a product, and the relay control unit starts operation by a logical product of the safety circuit unit and a relay drive unit corresponding to the relay control unit.