KR880004096Y1 - Refrigerator defrost circuit - Google Patents

Abstract

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Description

Refrigerator defrost circuit for power outage

1 is a circuit diagram of the present invention.

2 is a block diagram showing the internal structure of the special memory device.

Figure 3 is an algorithm showing the defrost function (ROUTINE) of the defrost circuit to which the present invention is applied.

4 (a) and 4 (b) are algorithm diagrams and timing diagrams for reading data stored in a special memory device in a defrost circuit to which the present invention is applied.

5 (a) and 5 (b) are algorithm diagrams and timing diagrams for reading data stored in a special memory device in a defrost circuit to which the present invention is applied.

6 (a) and 6 (b) are algorithm diagrams and timing diagrams showing enable and disable routines involved in storing in a special memory device.

7 (a) and 7 (b) are algorithm diagrams and timing diagrams showing erase routines involved in storing in a special memory device.

* Explanation of symbols for main parts of the drawings

8, 9, 10, 11: Photo Kapoor 12: special memory device

R ₁ -R ₅ : resistance

The present invention is a defrost circuit of a refrigerator with a built-in microcomputer as a control device. Even when the power failure is restored after a temporary power failure, the defrost time counted by the microcomputer until the power failure is preserved and counted until after the power failure. The defrosting time of the refrigerator is added to the defrosting time and the defrosting time to be counted after the power failure is restored so that the defrosting function of the refrigerator is normally maintained irrespective of occurrence of the power failure.

The defrosting circuit of a conventional refrigerator in which a microcomputer is incorporated as a control unit subtracts the driving time of the compressor controlled by the internal temperature from the defrosting time (9 hours or 4 hours) set by the software of the microcomputer at regular intervals. When the subtracted result is 0, the defrosting operation is performed by driving the defrost heater. However, each port of the microcomputer is caused by incomplete ground state of the refrigerator or power noise input through the AC power line. If noise occurs on the pulses input and output through the (PORT) line, this causes errors in the defrost time counted in the microcomputer. (In the case of a refrigerator in which the defrost time is set to 9 hours, 30) minute error) occurs, and the accurate defrosting operation is performed according to the preset defrosting time. Of course, there was no countermeasure, especially in the event of a power failure. For example, the sum of the defrost times counted in the microcomputer is 8 hours. When the refrigerator is reactivated by resuming the power failure, the built-in microcomputer is also 'off' at the time of power failure, and the defrost time counted up to the power failure stored in the internal memory is erased. Even if the computer is 'on' again, the defrost time stored in the internal memory is reset to the state of the circuit (9 hours). Because of this, if there is a temporary power failure, the defrosting operation of the refrigerator cannot be performed normally. Build up of frost on the evaporator surface and is Therefore there was a disadvantage that the service life of the refrigerator is reduced.

An object of the present invention is to solve the above-mentioned disadvantages, by using a special memory device (IC name: NMC 9306 / COP 494, manufacturer: NATIONAL SEMICONDUTOR CORP.) Of the microcomputer software, a predetermined defrost By storing and storing the data that depresses the compressor drive time every one minute from the time in the special memory device, the microcomputer reads the data stored in the special memory device when the data is restored after the power failure occurs. The defrosting function is normally performed because the subtraction function is performed. For example, even if the power failure is reset after the total of the compressor driving time has been 8 hours, and the power failure returns, the total of the special memory devices is 1 hour after the power failure is restored. When the elapsed time, the microcomputer will perform the defrosting dynamics, and it will normally By operating the upper circuit as well as configuring the photocoupler between the microcomputer and the input / output line of the special memory device, even if noise is generated at each input / output line of the microcomputer due to power supply noise or refrigerator incomplete ground state, By removing the noise generated by the electrically independent signal transmission characteristics to prevent the error occurs in the defrost time counted in the microcomputer, the configuration and operation effects of the present invention will be described in detail by the accompanying drawings.

1 is a circuit diagram of the present invention, in a refrigerator employing the microcomputer 7 as a control device, when the result value obtained by subtracting the compressor 4 driving time from a predetermined defrost time at a predetermined time interval is defrosted. The chip select output line (a '), clock output line (b'), data output line (c '), and data input line (d') of the microcomputer (7), in which software is configured to perform a function, are used for each port. Chip selector terminals (a) of the conventional special memory device 12 through the coupler (8) (9) (10) (11) and the resistors (R ₁ ) (R ₂ ) (R ₃ ) (R ₄ ), The data counted by the microcomputer 7 is stored in the special memory device 12 at predetermined time intervals by connecting to the clock terminal b, the data input terminal c and the data output terminal d. as to the configuration, the reference numeral of the AC input power supply is alternating current, 1. 2. 3 is a triac, 5. 6 is a fan and the defrost heater, the power transformer T, D ₁ Diode, R ₅ is the resistance, Vcc is the DC supply voltage.

Referring to the operation and effects of the present invention is the configuration as described above. In general, in controlling the function of the refrigerator, "HIGH" is used as the gate terminal of the triac (1) (2) for driving the compressor (4) and the fan (5) from the microcomputer (7) according to a predetermined condition such as high internal temperature. The compressor (4) and the fan (5) are driven by turning on the triac (1) and (2) by outputting a level signal. At this time, the triac (1) and (2) are at the "HIGH" level. The limit of the time that the signal is output is counted by the microcomputer 7 at regular intervals (1 minute) and stored in the internal memory. When the counted defrost time is 9 hours (or 4 hours), the microcomputer 7 ) Outputs the "HIGH" level signal to the gate terminal of the triac (3) to conduct the triac (3) to operate the defrost heater (6) to remove the frost accumulated in the high evaporator.

However, as described above, when there is a temporary power failure while the microcomputer 7 counts the defrost time, the microcomputer 7 inside the refrigerator is 'off' and data on the counted defrost time stored in the internal memory is also displayed. Even if the power failure is restored, the defrosting time of the refrigerator is reset to the initial state and counts the defrosting time from the beginning again.When a temporary power failure occurs, the defrosting time is delayed up to 9 hours and the evaporator surface inside the refrigerator is removed. In the frost was accumulated, thereby shortening the life of the refrigerator and reduce the reliability of the product.

In the present invention, in performing the defrosting function in the microcomputer 7, as shown in the algorithm of FIG. 3, the data stored in the special memory device 12 is stored at the time of initial set-up, when the refrigerator is powered on or when the power is restored. Read and refrigerate by this data value. Check the operation time of A routine and compressor (4) to perform general functions such as refrigeration, and subtract and record the data recorded in the special memory device (12) every 1 minute. When the data reaches 0 hours, there is a B-routine to perform the defrosting function. In performing the defrosting function such as power failure, the microcomputer 7 and the special memory device are damaged due to the ground failure of the refrigerator or the noise of external power. Noise generated in the signal pulses between the data input and output between (12) is almost eliminated by the signal transfer characteristics of each photocoupler (8-11) so that normal defrosting operation is performed regardless of power failure, and subtraction is performed by the microcomputer (7). The defrosting time is maintained for 9 hours or 4 hours depending on the preset option so that the frost can be prevented from occurring. All.

2 is a block diagram showing the internal structure of the special memory device 12 used in the present invention, which is output from the microcomputer 7 to the chip select signal and the data input signal for setting the special memory device 12. FIG. Selects READ / WRITE and selects the corresponding address in the storage device (PROM), the mode selection circuit and decoder circuit, and the signal storage device that temporarily stores the specified data in the storage device (PROM), and the data stored in this signal storage device. It is composed of a buffer for outputting to the data output terminal (d).

First, in the B routine in FIG. 3, the microcomputer 7 checks the compressor 4 driving time by one minute, subtracts the data recorded in the special memory device 12 by one minute, and rewrites the data. Same as

In order to rewrite the new data into the special memory device 12 as described above, the special memory device 12 is first activated to bring it into an operational state, erases the recorded data, and then stores the new data again. ), The operation stop state should be made, and such a series of functions are continuously performed at one minute intervals of the compressor 4 driving time, thereby reducing the defrost time.

That is, the routine for enabling the special memory device 12 to erase the data recorded in the special memory device 12 and to store new data is as shown in FIG. As the signal input to the memory device 12, as shown in FIG. 6 (a), the chip select terminal a becomes 1, the special memory device 12 is set, and then the start bit and the 4 bits through the data input terminal c. This is accomplished by sending data for an enable or disable 0 code and a 4-bit address number. Next, the data stored at the designated address of the special memory device 12 is erased by performing the erasing routine by the input signal as shown in FIGS. 7 (a) and 7 (b). After performing the routine, after recording the input signal as shown in Figs. 5 (a) and 5 (b) and the defrost time subtracted from the microcomputer 7 by the WRITE routine, Again, the special memory device 12 is stopped in operation through the disagree blueouts of FIGS. 6 (a) and 6 (b), thereby subtracting the special memory device 12 from the special memory device 12. One rewrite of the defrost time is completed.

On the other hand, the READ routine for reading the data stored in the special memory device 12 while the microcomputer 7 performs the routines of the third (a) and the third (b), and thus the microprocessor (7). The signals input and output between the special memory device 12 and the special memory device 12 are the same as those of the fourth (a) and the fourth (b). In this case, the data input terminal (c) of the special memory device 12 also includes a start bit, a READ OP code of 4 bits (1000), and a 4-bit address designation data, and is subtracted by the data output terminal (d). 16 bits of data about the defrost time are output and input to the microprocessor 7.

As described above, the present invention stores and stores data on the defrosting time, which is subtracted from the microcomputer, in the special memory device through the photocoupler once per minute, even when the power failure is restored after a temporary power failure. Since the defrost circuit is operated, frost does not accumulate on the surface of the evaporator inside the refrigerator, which extends the lifespan of the refrigerator and improves the reliability of the defrost function of the refrigerator. It is a useful design to eliminate the error.

Claims (1)

In a refrigerator employing a microcomputer as a control device, the chip select output line (a ') and the clock of the microcomputer configured to perform defrosting operation by subtracting the compressor driving time from a predetermined defrosting time at a predetermined time interval. Output line (b '), data output line (c') and data input line (d ') are connected to each photocoupler (8) (9) (10) (11) and resistor (R ₁ ) (R ₂ ) (R ₃ ) Subsequently connected to the chip select terminal (a), the clock terminal (b), the data input terminal (c) and the data output terminal (d) of the conventional special memory device 12 via R ₄ . A defrost circuit of a refrigerator for power failure, characterized in that the data of the defrost time is stored in the special memory device (12) at a predetermined time interval.