Water shortage detection circuit of water electric appliance

Abstract

A water shortage detection circuit of a water electric appliance comprises a port CN6 used for being connected with a water pump, the positive electrode of the port CN6 receives a voltage, and the negative electrode of the port CN6 is connected with the drain electrode of an MOS tube Q1; a source electrode of the MOS tube Q1 is grounded through a sampling resistor R46, the source electrode is further connected with the single-chip microcomputer through a resistor R32 and used for collecting working voltage of the water pump, a grid electrode of the MOS tube Q1 is connected with the single-chip microcomputer through a resistor R24 and used for controlling on-off of the MOS tube Q1, firstly, a machine is powered on and controlled in a water shortage state, at the moment, the single-chip microcomputer obtains a working current AD value of the water pump through the resistor R32 and records the working current AD value, and the working current AD value of the water pump is recorded. When a machine works later, the single-chip microcomputer compares the working current AD value with the current current so as to identify whether the current state is a water shortage state, and the water shortage identification circuit can realize water shortage identification without a flow sensor.

Description

Technical Field

[0001] The utility model relates to the field of water appliances, in particular to a water shortage detection circuit for water appliances. Background Art

[0002] Existing water appliances such as coffee machines need to add a flow sensor to achieve quantitative and water shortage protection, and there is no pressure sensor in such devices on the market, so overpressure electronic control protection cannot be achieved. With the continuous improvement of people's living standards, people have put forward higher requirements for the quality of life. In order to better control coffee machines and water dispensers, new improvements are now made to the products. Summary of the Utility Model

[0003] To solve the above problems, the technical solution provides a water shortage detection circuit for water appliances.

[0004] To achieve the above object, the technical solution is as follows:

[0005] A water shortage detection circuit for water appliances includes a port CN6 for connecting a water pump. The positive pole of the port CN6 receives a voltage, and the negative pole is connected to the drain of a MOS transistor Q1.

[0006] The source of the MOS transistor Q1 is grounded through a sampling resistor R46, and the source is also connected to a single-chip microcomputer through a resistor R32 for collecting the working voltage of the water pump. The gate of the MOS transistor Q1 is connected to the single-chip microcomputer through a resistor R24 for controlling the on-off of the MOS transistor Q1.

[0007] In some embodiments, a diode D5 is provided between the positive and negative poles of the port CN6.

[0008] In some embodiments, the source of the MOS transistor Q1 is also grounded through a resistor R45.

[0009] In some embodiments, the gate of the MOS transistor Q1 is grounded through a resistor R15.

[0010] The beneficial effect of this application is as follows:

[0011] First, when the machine is powered on and controlled in a water shortage state, at this time, the single-chip microcomputer obtains the AD value of the working current of the water pump through the resistor R32 and records it. Then, when the machine works, the single-chip microcomputer will compare the working current AD value with the current current to identify whether the current is in a water shortage state. The circuit of this application can achieve water shortage identification without a flow sensor. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the drawings required for description in the embodiments will be briefly introduced below.

[0013] Figure 1 is the schematic flow chart of the embodiment of the present utility model;

[0014] Figure 2 is the schematic circuit structure diagram of the embodiment of the present utility model. Specific embodiments

[0015] In order to make the technical problems, technical solutions and beneficial effects solved by the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0016] Please refer to Figure 1-2 As shown, a water shortage detection circuit for a water appliance includes a port CN6 for connecting to a water pump. The positive pole of the port CN6 receives a voltage, and the negative pole is connected to the drain of a MOS transistor Q1;

[0017] The source of the MOS transistor Q1 is grounded through a sampling resistor R46, and the source is also connected to a single-chip microcomputer through a resistor R32 for collecting the working voltage of the water pump. The gate of the MOS transistor Q1 is connected to the single-chip microcomputer through a resistor R24 for controlling the on / off of the MOS transistor Q1.

[0018] When the machine is powered on, it is judged whether the machine has been calibrated. If it has been calibrated, it enters the standby mode. If not, it enters the water pump calibration mode.

[0019] After entering the calibration mode, (the machine cannot add water) the water pump is started to run for 10 seconds and the AD value of the current when the water pump is running in the current waterless state is recorded. Then when the machine works, the single-chip microcomputer will compare the working current AD value with the current current to identify whether the current is a water shortage state. The circuit of this application can realize water shortage identification without a flow sensor;

[0020] When the obtained AD value is consistent with the stored AD value, it indicates that the current is a water shortage state, and then the MOS transistor is turned off to disconnect the water pump;

[0021] When the obtained AD value is lower than the stored AD value, it is a wire break or a water pump failure;

[0022] Since there is a certain resistance when the water pump works after water is added, when the obtained AD value is higher than the stored AD value and lower than the AD value of the maximum load current of the water pump, it is in a normal working state;

[0023] When the obtained AD value is higher than the AD value of the maximum load current of the water pump, it is a short circuit or a water pump failure.

[0024] This application uses an external standard flow sensor to record the water flow corresponding to each speed of the water pump (PWM regulation), which is specifically obtained by reciprocally turning on and off the MOS transistor. When the water pump is actually running, the water flow time is calculated to obtain the water output (the accuracy can reach 5%).

[0025] This application also sets system self-tuning, specifically:

[0026] 1. After the first power-on, the system runs the water pump at the maximum power and the heating is fully on, and the temperature is measured until it stabilizes at a stable value.

[0027] 2. After calibrating the current stable temperature, calculate the required temperature value, adjust the water output according to the outlet water temperature to reach the set temperature stable value, and record the current water pump speed.

[0028] 3. Operate the calibrated water volume normally, and turn on the heating to enter the PID program for constant temperature operation.

[0029] In some embodiments, a diode D5 is provided between the positive and negative electrodes of the port CN6.

[0030] In some embodiments, the source electrode of the MOS transistor Q1 is also grounded through a resistor R45.

[0031] In some embodiments, the gate electrode of the MOS transistor Q1 is grounded through a resistor R15.

[0032] Finally, the beneficial effects of this application are as follows:

[0033] 1. The machine does not require a flow sensor and can achieve precise flow control.

[0034] 2. The machine does not require a flow sensor and can achieve water shortage protection.

[0035] 3. When the machine does not require an external sensor, it has effective protection against open circuit, short circuit or blockage.

[0036] 4. It effectively solves the problem that the control system becomes unstable due to the changes in the water pump current and water flow after the water pump ages.

[0037] The above are only the preferred embodiments of this application and are not used to limit the scope of implementation of this application. Other embodiments with the same or similar principles and basic structures as this application are within the protection scope of this application.

Claims

1. A water shortage detection circuit for water appliances, characterized in that: It includes a port CN6 for connecting a water pump, wherein the positive electrode of the port CN6 receives a voltage, and the negative electrode is connected to the drain of the MOS tube Q1; The source of the MOS tube Q1 is grounded through a sampling resistor R46, and is also connected to a single-chip microcomputer through a resistor R32 for collecting the working voltage of the water pump. The gate of the MOS tube Q1 is connected to the single-chip microcomputer through a resistor R24 ​​for controlling the on and off of the MOS tube Q1.

2. The water shortage detection circuit for water-related electrical appliances according to claim 1, characterized in that: A diode D5 is provided between the positive and negative electrodes of the port CN6.

3. The water shortage detection circuit for water-related electrical appliances according to claim 1, characterized in that: The source of the MOS tube Q1 is also grounded through a resistor R45.

4. The water shortage detection circuit for water-related electrical appliances according to claim 1, characterized in that: The gate of the MOS transistor Q1 is grounded through a resistor R15.

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