JPS5830704B2 - Electric cooker output control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to digitally control the output of an electric cooking device such as a microwave oven or an electric oven. For example, when using a conventional phase control method for a microwave oven, a large surge voltage is generated when the 5CR1 or triac is turned off, causing problems such as destruction of the high voltage diode and deterioration of the magnetron. Furthermore, conventional output control was performed using a mechanical timer that could be adjusted in two or three stages, but when controlling in multiple stages, the cam and contact configuration of the mechanical timer became complicated, resulting in high cost and reliability issues. There was a problem. The present invention digitally controls the output in order to eliminate the above-mentioned drawbacks, and also enables multi-stage output control, and is very useful in practice. One embodiment will be explained below with reference to a block diagram. Reference numeral 1 is a keyboard for output selection, and there are ten types of switches from 1 to 0, which are turned on only when pressed. An encoder 2 converts the signal from the keyboard 1 into a binary code according to the 8-4-2-1 code. 3 is a storage circuit for storing the binary code from the encoder 2, and is composed of 4 bits. 4 is a decimal counter that counts clock pulses. That is, the counter performs QA based on the clock pulse.
- The binary code represented by the 4 bits of Qd changes, and the change is [QA QB QcQd).

It cycles between the base value [0000] and the maximum value (1001') at a constant cycle. The operating condition for such a counter is to set the start switch 5 to o.
When n, the AND circuit 6 performs an AND operation, and the clock pulses are counted based on that signal. Moreover, when the start switch 5 is off, the counter 4
An inverter 7 as a presetting means is inserted between the start switch 5 and the counter 4 so that the count content of is preset to a specific value (for example, at9n (hereinafter referred to as the numerical value "9")). Therefore, when the start switch 5 is turned on, the value (" 9
”). The start switch 5 is kept closed and turned off at the end of a predetermined time of a separately determined timer. 8 is a binary output signal from the memory circuit 3. This is a coincidence detection circuit that detects coincidence with the counted contents of the counter 4. As shown in FIG. A predetermined value tt9jj detection gate that detects the numerical value "9" among the counted contents opens the gate when the counted contents of the counter 4 reaches 1.9. 10 is reset by the output tt1jj from the coincidence detection circuit 8, and outputs a signal when set by a flip-flop set by the output from the detection gate 9.11 is the output from this flip-flop 10. 12 is a "0" detection OR gate that closes the gate when there is no output from the memory circuit 3. 12 is a "0" detection OR gate that closes the gate when there is no output from the memory circuit 3. 13 is a gate configured to AND the respective outputs from the 1'0'' detection OR gate 12 and the AND gate 11; 14 is a control circuit operated by the output from the gate 13; 15 to turn on the power supply circuit 16 of the load R.
- is turned off. During output control, flip-flop 1 is used as explained later.
0 is output periodically, therefore, the on-off control of the power supply circuit 16 by the control circuit 14 is substantially based on the cycle of the flip-flop 10, but due to the presence of the AND gate 11, the start switch 5 can perform such control. Conditioning the operating state of circuit 14. In addition, the load R is a magnetron in the case of a microwave oven,
If it is electrically open, it corresponds to an electric heater. 17 is a binary → hexadecimal decoder that converts the input from keyboard 1 to 7.
It is displayed on the segment display 18. Next, the operation of the present invention will be explained in terms of a microwave oven with reference to the time chart in FIG. tt 9 pp
If you press the numeric key tt 5pp (that is, set the output level to ``5'') on the output selection keyboard 1, the encoder 2 will change the binary code (0101
) and stored in the next memory circuit 3, and its output enters the decoder 17 and displays 5'' on the display 18, and is input to the ``'0'' detection OR gate 12 and the coincidence detection circuit 8, which outputs the OR gate 12. Leave it open. Next, after setting a timer (not shown) to a certain time and then turning on the start switch 5 to start cooking, the AND circuit 6 is ANDed and the clock pulse CP shown in FIG. 2A is input to the counter 4. Counter 4 is tt
9 Start counting from n and send the output to the coincidence detection circuit 8. The output from the counter 4 is shown in FIG. Since the counter 4 was previously set to a numerical value of 9'', when the start switch 5 was turned on, the 19'' signal was set to tt.
9 is sent to the pp detection gate 9, which opens the gate 9 and sets the flip-flop 10. The output of the flip-flop and the signal from the start switch 5 open the AND gate 11, and the next gate 13 is connected to the signal from the OR gate 12. Together with the signal, the opening control circuit 14 is operated and the power supply circuit 16 is energized. Therefore, as soon as the start switch is turned on, the load (magnetron) oscillates and starts cooking. On the other hand, the tt5jj signal (0101) is input from the memory circuit 3 to the coincidence detection circuit 8, so that the counter 4
When the fifth signal, ie, the (0101) signal, is input, a match is established, and at that time, as shown in FIG. 11 is closed, the control circuit 14 is turned off and the power supply circuit 16 of the L magnetron is deenergized. The flip-flop 10 maintains the reset state, but the 1'9" detection gate 9 detects the count contents of the counter 4 ((9p
When the output becomes p (t1jj), the flip-flop 10 is inverted again to the set state and the control circuit 14 is operated. Each time the counter content reaches tt9jj), it is set to the first logic state, and then the memory circuit 5
act as a binary selection means which is set to a second logic state depending on the amount of time corresponding to the content stored in the memory. The output of the memory circuit 3 when the output level of the keyboard 1 is set to 't5'' is shown in FIG. 2, and the output of the number output circuit 8 is shown in FIG. The outputs of the flip-flop 10 are respectively shown in FIG. It oscillates during the period. In other words, when the output level is set to ``5'', the output of the magnetron will be -0, and when the set time of the timer is over, the start switch 5 will be turned off and cooking will be completed. By selecting the output level 3 using keys with meanings corresponding to the levels, -t, ``'' multi-level 0 can be output.
10 Output control is possible. By increasing the counting capacity by increasing the number of counters compared to decimal ones, and by increasing the number of bits of the memory circuit that stores the output from the keyboard encoder, it is possible to easily provide multi-stage output control. Of course, in this case, multiple keys are used to set one output, but each key has a meaning corresponding to each output level, so when these keys are operated in combination, The output level will also be set according to the key combination. Because the present invention is as described above, it is possible to control the output even with short cooking times such as microwave ovens, and SCR.
Since it is an on-off control rather than a phase control such as a light attack, it does not generate surge voltage or noise. According to the present invention, for on/off output control,
A counter that takes a periodic counting state is used. Therefore, depending on the contents of the counter, it may take a while at the start of cooking;
A situation may occur in which heating energy is not output for a period of 0 seconds), and for example, if the cooking time is very short, sufficient heating may not be achieved. There is no problem, and cooking starts immediately after control starts. Further, according to the present invention, the desired output level can be set immediately by simply operating the key for setting the load output level on the keyboard, regardless of the previous output level setting contents, and the digital control However, it would be a shame if the operation of the cooker was complicated.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating an output control device for an electric cooking device according to the present invention, and FIG. 2 is a time chart thereof. 1...keyboard, 2...encoder, 3...memory circuit, 4...counter, 8...-number output circuit, 1
0...Flip-flop, 14...Control circuit, 16
...Load power supply circuit.

Claims (1)

[Claims] 1 A load serving as a cooking heat source, a storage means for storing the output level of the load in a binary code, 2
A counter whose evolutionary code changes, the change cycling between a base value and a maximum value at a constant cycle, the counter being set to a first logic state for each specific value of each cycle,
Thereafter, binary selection means is set to a second logic state according to the amount of time corresponding to the binary code stored in the storage means, and the power supply circuit of the load is set to zero by the output of the binary selection means.
A control circuit that is turned off, an operation setting means that puts the control circuit in an operating state, and a presetting means that presets the counter to the specific value so that the counting operation of the counter starts from the specific value when the control circuit starts operating. , an output control device for an electric cooker.