KR950004271B1 - Circuit and method of washing water clearness detection - Google Patents

Abstract

a detecting device for detecting the cleanliness of washing water supplied to a washing machine; a control device for comparing a signal of cleanliness received by the detecting device with a predetermined reference value so as to generate a PWM signal whose duty ratio is regulated; a voltage generator for generating a predetermined voltage according to the PWM signal; and a current control section for controlling the currents supplied to the detecting device according to the output signal of a smoothing section.

Description

Washing water cleanliness detection circuit and method of washing machine

1 is an explanatory diagram showing a state in which a detection device for detecting the cleanliness of the wash water is installed in the drain of the conventional washing machine;

2 is a circuit diagram showing an embodiment of the sensing device of FIG.

3 is a washing water cleanliness detection circuit diagram of a washing machine according to the present invention,

4 is a waveform diagram for explaining pulse width modulation.

5 is a flowchart showing a system program of the control device according to the present invention.

* Explanation of symbols for the main parts of the drawings

11: photocoupler 12: microcomputer

15: voltage generating unit 14: smoothing unit

13 current control unit 11a photodiode

11b: phototransistor

The present invention relates to a washing water cleanliness detection circuit of a washing machine.

Conventionally, a washing machine has a photocoupler 2 installed as a sensing device in a drain 1 as shown in FIG. 1 in order to detect the cleanliness of wash water discharged through a drain.

In Figure 1, number 3 is the drain valve, 4 is the motor, 5 is the gear mechanism, 6 is the screw, 7 is the inner tank of the washing machine, 7 'is the washing tank, 8 is the water inlet, 9 is the water supply To indicate the valve.

These descriptions are common and will be omitted.

FIG. 2 is a view illustrating an example of a conventional washing water cleanliness sensing device. The washing water cleanliness sensing device installed in the drain 1 includes a photodiode 2a that emits light in the photocoupler 2 and a photo receiving light. When the wash water flows between the transistors 2b, the voltage changes on the output side of the phototransistor 2b in accordance with the cleanliness of the wash water. Accordingly, the microcomputer 10 can determine the cleanliness of the wash water. For example, if the applied voltage is high, the cleanliness of the wash water is high, and if the voltage is low, it is determined that the freshness of the wash water is low.

However, according to the prior art, the following problems occur.

Cleanliness sensors of wash water, such as photocouplers, have not been able to accurately provide microcomputers with voltages corresponding to the cleanliness of wash water due to errors in their manufacture.

That is, when detecting the wash water when the cleanliness is 3.5V, a voltage of less than 3.5V or more than 3.5V was detected depending on the cleanliness sensor.

Therefore, the same washing was not performed according to the washing machine.

An object of the present invention is to provide a wash water cleanliness detection circuit of a washing machine that compensates for errors in a cleanliness sensing device such as a photocoupler so that the washing machine can accurately determine the cleanliness. .

In order to achieve the above object, according to the present invention, in the washing machine having a sensing device for monitoring the cleanliness of the wash water in the drain, a signal corresponding to the cleanliness of the wash water is input by the detection device of the water supply in the initial washing state The controller then determines whether the signal is equal to the set reference value. If the input signal is larger or smaller than the reference value, the PWM signal with the duty ratio adjusted accordingly is output.

The PWM signal whose duty ratio is adjusted is input to the voltage generator, and the voltage generator generates a predetermined voltage scaled according to this PWM signal.

Subsequently, the smoothing unit removes the ripple of the predetermined voltage output from the voltage generating unit and outputs the ripple. The current controller inputs the smoothed voltage to control the current supplied to the sensing device according to its magnitude. Therefore, the sensing device outputs a sensing signal whose error is compensated to the control device.

The present invention will be described below with reference to the attached 3 and 4 as follows.

3 is a view illustrating a washing water cleanliness detection circuit of a washing machine according to the present invention, and a photocoupler 11 and a washing water input through the photocoupler 11 as a sensing device for detecting the cleanliness of the washing water during initial water supply. The microcomputer 12 outputs a PWM signal having a controlled tutor ratio according to a comparison result by comparing the cleanliness signal with a predetermined reference value, and a voltage generator for generating a predetermined voltage according to the PWM signal output from the microcomputer 12. 15, a smoothing part 14 for removing and smoothing ripple of a predetermined voltage output from the voltage generating part 15, and a photo according to the magnitude of the smoothed voltage output from the smoothing part 14 It consists of a current control unit 13 for controlling the magnitude of the current supplied to the coupler (11).

Here, reference numeral P1 denotes a cleanliness signal input port of the microcomputer 12, P2 denotes a PWM signal output port of the microcomputer 12, R1-R9 denotes a resistor, C1-C2 denotes a capacitor, and Q3 represents a transistor, 11a represents a photodiode emitting light, and 11b represents a phototransistor receiving light.

4 is a diagram illustrating one form of a PWM signal output from the microcomputer 12. The adjustment of the duty ratio means that the interval between the high level signal and the low level signal is adjusted. it means.

That is, if the cleanliness signal input through the photocoupler 11 is larger than the set reference value, the microcomputer 12 outputs the PWM signal by making the high level time section of FIG. 4 longer than the low level start time section, and the cleanliness signal is If it is smaller than the set reference value, the PWM signal is output by making the low level time interval longer than the high level time interval.

An operation according to the configuration of FIG. 3 will be described with reference to FIGS. 3 and 5. First, the cleanliness of the wash water supplied to the initial washing state is the highest state.

The voltage corresponding to the cleanliness at this time is stored in the microcomputer 12 as a (3.5V) reference value.

When the washing machine starts to operate, the washing water is supplied through the water supply port 8 in FIG. 1, and the washing water is supplied until the drain valve 3 of the drain 1.

Accordingly, the photocoupler 11 senses the cleanliness of the wash water and transfers it to the input port P1 of the microcomputer 12 as a voltage component. That is, the photodiode 11a of the photocoupler 11 The light emitting state and the phototransistor 11b are in the light receiving state. Therefore, when the wash water flows between the photodiode 11a and the phototransistor 11b, a voltage change occurs on the output side b of the phototransistor 11b.

At this time, the microcomputer 12 first compares the cleanliness signal of the wash water input through the input port P1 with a reference value of 3.5V and adjusts the tube ratio to a higher level through the output port P2 than the current state. And outputs a PWM signal as shown in FIG. 4 with a relatively large time section of the signal to the voltage generator 15. If it is small, the duty ratio is adjusted to output the PWM signal to the voltage generator 15 in which the time period of the low level signal is relatively larger than the current state.

In addition, when the cleanliness signal is equal to the set reference value 3.5V, the PWM signal having the generated tut ratio is output to the voltage generator 13 as it is and then returned to the initial state. As such, the microcomputer 12 checks whether the current washing process is an early water supply process, and performs the above function only at the time of initial water supply.

The voltage generator 15 generates a predetermined voltage according to the input PWM signal, and the resistors R4 and R5 and the capacitors C1 and C2 of the smoother 14 smooth and remove the ripple of the generated voltage. After that, it is input to the current controllers R4 and R5. At this time, the voltage across the resistor R2 of the current control unit 13 is generated by the voltage drop between the base and the emitter of the transistors Q1 and Q2 of the current control unit 13 as shown in Equation 1 below.

VR2 = Output voltage of smoothing part -0.6V (Q2) -06V (Q1) ... (1)

Therefore, a current such as the following formula (2) flows through the photodiode 11a of the photocoupler 11.

·· ·········· · ··(2)

As a result, the washing water cleanliness detection circuit of the present invention reduces the amount of current flowing through the photodiode 11a by extending the high level of the PWM signal when the cleanliness signal is greater than 3.5V, thereby reducing the amount of current flowing into the photodiode 11a. When the cleanliness signal is less than 3.5V and the cleanness signal is less than 3.5V, the low level state of the PWM signal is increased to increase the amount of current flowing through the port diode 11a, thereby increasing the amount of current to the photodiode 11a. It causes a lot more light than it is. Therefore, the output voltage of the phototransistor 11b is also increased or decreased in proportion to the current increase or decrease. Therefore, when the initial washing water is supplied, the cleanliness signal of the washing water is close to the set reference value 3.5V, accordingly. The photocoupler accurately senses cleanliness and further allows the washing machine to perform the washing accurately.

Claims (5)

Detecting device for detecting the cleanliness of the wash water supplied to the initial water supply of the washing machine; And comparing the cleanliness signal inputted through the sensing device with a set reference value. A control device for generating a PWM signal with a tutti ratio adjusted according to the comparison result; A voltage generator configured to generate a predetermined voltage according to the PWM signal; Washing water cleanliness detection circuit of the washing machine, characterized in that the current control unit for controlling the amount of current supplied to the sensing device according to the output signal of the smoothing unit. The washing water cleanliness detection circuit according to claim 1, further comprising a smoothing unit for smoothing an output signal of the voltage generating unit between an output side of the voltage generating unit and an input side of the current control unit. The washing water cleanliness detection circuit of a washing machine according to claim 2, wherein the smoothing part is composed of a resistor and a capacitor. The washing water cleanliness sensing circuit of claim 1, wherein the sensing device is a photocoupler. A washing machine having a sensing device for detecting cleanliness of wash water in a drain, the method comprising: checking whether the current washing process is an initial water supply process and returning the initial state; Comparing the cleanliness signal of the wash water input through the sensing device with a set reference cleanliness value if the initial water supply process is performed; When the input cleanliness signal and the set reference value is the same, generating the PWM signal as the set duty ratio, and if it is small or large, generating a PWM signal by adjusting the tube ratio; The current supplied to the sensing device according to the generated PWM signal Controlling; Washing water cleanness detection method of the washing machine characterized in that it comprises a.