Liquid level detection circuit of beverage machine and beverage machine

Abstract

The utility model provides a liquid level detection circuit of a beverage machine and the beverage machine, the circuit comprises a bias voltage circuit, a pulse generation circuit and a voltage conversion circuit, the pulse generation circuit is respectively connected with the bias voltage circuit, a liquid level sensing module and the voltage conversion circuit; the pulse generation circuit outputs pulse voltage based on bias voltage provided by the bias voltage circuit, the voltage conversion circuit converts the pulse voltage into direct-current voltage, the liquid level induction module is arranged in a liquid level container of the beverage machine, and the liquid level induction module is connected with the liquid level sensor under the condition that the liquid level induction module is in contact with liquid. When the liquid sensing module is in contact with the liquid, the voltage conversion circuit outputs a second direct-current voltage representing that the liquid in the liquid container is sufficient, and when the liquid sensing module is not in contact with the liquid, the voltage conversion circuit outputs a first direct-current voltage representing that the liquid container needs to be supplemented with the liquid, and the second direct-current voltage is smaller than the first direct-current voltage; the circuit indicates whether liquid needs to be supplemented or not by outputting different direct-current voltages, and accurate and reliable reference basis is provided for supplementing liquid to a liquid container in time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of beverage machines, in particular to a liquid level detection circuit of a beverage machine and the beverage machine. BACKGROUND

[0002] In existing applications, many beverage machines (such as coffee machines) are provided with liquid containers, and water or other liquids are pre-stored in the liquid containers. According to the requirements of the beverage preparation process, the pre-stored liquids in the liquid containers are used to complete the beverage preparation, thereby improving the preparation efficiency of the beverages.

[0003] It can be understood that, as the beverage is prepared, the pre-stored liquid in the liquid container will gradually decrease. In order to ensure the normal operation of the beverage machine, it is necessary to detect the liquid storage in the liquid container at all times. Therefore, how to detect the liquid storage of the liquid container of the beverage machine and timely supplement the liquid in the liquid container to ensure the normal operation of the beverage machine has become one of the technical problems to be solved by the technical personnel in the field. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the present application is committed to providing a liquid level detection circuit of a beverage machine and the beverage machine, which detects the liquid storage in the liquid container of the beverage machine and provides a reference basis for timely supplementing the liquid in the liquid container, thereby helping to ensure the normal operation of the beverage machine.

[0005] In a first aspect, the present application provides a liquid level detection circuit of a beverage machine, the beverage machine comprising a liquid container, and a liquid level sensing module being arranged in a containing space of the liquid container, the circuit comprising: a bias voltage circuit, a pulse generation circuit and a voltage conversion circuit, wherein,

[0006] The pulse generation circuit is connected with the bias voltage circuit, the liquid level sensing module and the voltage conversion circuit respectively;

[0007] The bias voltage circuit is used for outputting a bias voltage;

[0008] The pulse generation circuit outputs a pulse voltage based on the bias voltage;

[0009] The voltage conversion circuit is used for converting the pulse voltage into a direct current voltage;

[0010] In the case that the liquid level sensing module does not contact with the liquid in the liquid container, the voltage conversion circuit outputs a first direct current voltage, and the first direct current voltage represents that the liquid container needs to be supplemented with liquid;

[0011] In the case that the liquid level sensing module contacts with the liquid in the liquid container, the voltage conversion circuit outputs a second direct current voltage, and the second direct current voltage represents that the liquid in the liquid container is sufficient, wherein the second direct current voltage is less than the first direct current voltage.

[0012] In an alternative embodiment, the liquid level detection circuit according to the first aspect of the present application further comprises a pulse absorption circuit, wherein

[0013] the pulse absorption circuit is connected between the pulse generation circuit and the liquid level sensing module;

[0014] the pulse absorption circuit is configured to absorb the electric energy of the pulse voltage output by the pulse generation circuit when the liquid level sensing module is in contact with the liquid.

[0015] In an alternative embodiment, the bias voltage circuit comprises a first voltage dividing resistor and a second voltage dividing resistor, wherein

[0016] one end of the first voltage dividing resistor is configured to receive a reference voltage, the other end of the first voltage dividing resistor is connected to one end of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is grounded;

[0017] a connection point of the first voltage dividing resistor and the second voltage dividing resistor is configured to output the bias voltage to the pulse generation circuit.

[0018] In an alternative embodiment, the pulse generation circuit comprises a first comparator, a positive feedback resistor, a negative feedback resistor, and an energy storage capacitor, wherein

[0019] the positive feedback resistor is connected between the positive input terminal of the first comparator and the output terminal of the first comparator;

[0020] the negative feedback resistor is connected between the negative input terminal of the first comparator and the output terminal of the first comparator;

[0021] one end of the energy storage capacitor is connected to the negative input terminal of the first comparator, and the other end of the energy storage capacitor is grounded;

[0022] the positive input terminal of the first comparator is further configured to receive the bias voltage;

[0023] the output terminal of the first comparator is further configured to output the pulse voltage.

[0024] In an alternative embodiment, the voltage conversion circuit comprises a unidirectional conduction circuit and a filter circuit, wherein

[0025] the input terminal of the unidirectional conduction circuit is connected to the pulse generation circuit, the output terminal of the unidirectional conduction circuit is connected to the first terminal of the filter circuit, and the conduction direction of the unidirectional conduction circuit is the same as the voltage drop direction of the filter circuit;

[0026] the second terminal of the filter circuit is grounded.

[0027] The connection point of the unidirectional conduction circuit and the filter circuit is used for outputting the first direct current voltage or the second direct current voltage.

[0028] In an alternative embodiment, the filter circuit comprises a filter resistor and a filter capacitor, wherein,

[0029] One end of the filter resistor is a first end of the filter circuit, and the other end of the filter resistor is a second end of the filter circuit.

[0030] The filter capacitor is connected in parallel with the filter resistor.

[0031] In an alternative embodiment, the liquid level inspection circuit provided by the first aspect of the application further comprises a control module connected with the voltage conversion circuit, the control module being configured to receive the direct current voltage output by the voltage conversion circuit, wherein,

[0032] The control module outputs a first control signal to control a liquid supplementing device of the beverage machine to supplement liquid into the liquid container, the first control signal being generated according to the first direct current voltage.

[0033] The control module outputs a second control signal to control the liquid supplementing device to stop supplementing liquid into the liquid container, the second control signal being generated according to the second direct current voltage.

[0034] In an alternative embodiment, the control module comprises a microcontroller, wherein,

[0035] A voltage collection port of the microcontroller is connected with the voltage conversion circuit.

[0036] The microcontroller is configured to output the first control signal in response to the first direct current voltage, or output the second control signal in response to the second direct current voltage.

[0037] In an alternative embodiment, the control module comprises a threshold voltage circuit and a window comparison circuit, wherein,

[0038] The window comparison circuit is connected with the voltage conversion circuit, and the voltage conversion circuit outputs the first direct current voltage or the second direct current voltage to the window comparison circuit.

[0039] The threshold voltage circuit is configured to output a first threshold voltage to the window comparison circuit.

[0040] The window comparison circuit outputs the first control signal when the first direct current voltage is greater than the first threshold voltage, and outputs the second control signal when the second direct current voltage is less than the first threshold voltage.

[0041] In an optional implementation, the threshold voltage circuit is further configured to output a second threshold voltage to the window comparison circuit, and the second threshold voltage is greater than the first threshold voltage.

[0042] The window comparison circuit outputs the second control signal when the first direct current voltage is greater than the second threshold voltage.

[0043] In an optional implementation, the threshold voltage circuit comprises a third voltage dividing resistor, a fourth voltage dividing resistor, and a fifth voltage dividing resistor, wherein,

[0044] The third voltage dividing resistor, the fourth voltage dividing resistor, and the fifth voltage dividing resistor are connected in series to obtain a series branch.

[0045] One end of the series branch is configured to receive a reference voltage, and the other end of the series branch is grounded.

[0046] A connection point between the third voltage dividing resistor and the fourth voltage dividing resistor is configured to output the second threshold voltage to the window comparison circuit.

[0047] A connection point between the fourth voltage dividing resistor and the fifth voltage dividing resistor is configured to output the first threshold voltage to the window comparison circuit.

[0048] In an optional implementation, the window comparison circuit comprises a second comparator and a third comparator, wherein,

[0049] A positive input terminal of the second comparator is configured to receive the second threshold voltage, and a negative input terminal of the second comparator is connected with a positive input terminal of the third comparator.

[0050] A negative input terminal of the third comparator is configured to receive the first threshold voltage.

[0051] An output terminal of the second comparator and an output terminal of the third comparator are connected, serving as an output terminal of the window comparison circuit.

[0052] A connection point between the negative input terminal of the second comparator and the positive input terminal of the third comparator is connected with the voltage conversion circuit.

[0053] In a second aspect, the present application provides a beverage machine, comprising a liquid container, a liquid level sensing module, a liquid supplementing device, and a liquid level detection circuit according to any one of the first aspect of the present application, wherein,

[0054] The liquid level sensing module is arranged in the containing space of the liquid container.

[0055] The liquid level detection circuit is connected with the liquid level sensing module and the liquid supplement device respectively.

[0056] The liquid level detection circuit controls the liquid supplement device to supplement liquid into the liquid container or controls the liquid supplement device to stop supplementing liquid into the liquid container according to the contact state between the liquid level sensing module and the liquid in the liquid container.

[0057] In an alternative embodiment, the liquid container is made of conductive material and is grounded, the liquid level sensing module comprises a liquid level probe arranged at a preset height in the liquid container and spaced apart from the liquid container, and the liquid level probe is connected with the liquid level detection circuit.

[0058] Alternatively, the liquid level sensing module comprises two liquid level probes arranged at a preset height in the liquid container and spaced apart from each other, one of the two liquid level probes is connected with the liquid level detection circuit, and the other is grounded.

[0059] Based on the above, the liquid level detection circuit provided by the present application comprises a bias voltage circuit, a pulse generation circuit and a voltage conversion circuit. The bias voltage circuit outputs a bias voltage, the pulse generation circuit outputs a pulse voltage based on the bias voltage, and the voltage conversion circuit converts the pulse voltage into a direct current voltage. The liquid level sensing module is arranged in the liquid level container of the beverage machine. When the liquid level sensing module is in contact with the liquid, due to the conductivity of the liquid, part of the electric energy of the pulse voltage is absorbed, and the second direct current voltage representing the sufficiency of the liquid in the liquid container is obtained by the voltage conversion circuit. Correspondingly, when the liquid sensing module is not in contact with the liquid, the branch in which the liquid sensing module is located is equivalent to an open circuit, and the pulse voltage is all input to the voltage conversion circuit. The first direct current voltage obtained by the voltage conversion circuit is naturally different from the second direct current voltage, and the first direct current voltage can represent that the liquid container needs to be supplemented with liquid. Based on this, the liquid level detection circuit provided by the present application can realize the liquid level detection of the liquid container of the beverage machine, and can indicate whether the liquid container needs to be supplemented with liquid by outputting different direct current voltages, thereby providing an accurate and reliable reference basis for timely supplementing liquid to the liquid container, effectively avoiding the influence of electrode scaling on detection accuracy, and being applicable to detecting any type of liquid and helping to ensure the normal operation of the beverage machine.

[0060] Further, by adjusting the position of the liquid level sensing module in the liquid container, the timing of outputting the first direct current voltage and the second direct current voltage can be adjusted, thereby meeting the detection requirements of different liquid levels and having a wide range of applications. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0062] Figure 1 is a structural block diagram of a liquid level detection circuit provided by the present application.

[0063] Figure 2 is a structural block diagram of another liquid level detection circuit provided by the present application.

[0064] Figure 3 is a topological diagram of a liquid level detection circuit provided by the present application.

[0065] Figure 4 is a structural block diagram of another liquid level detection circuit provided by the present application.

[0066] Figure 5 is a topological diagram of another liquid level detection circuit provided by the present application.

[0067] Figure 6 is a topological diagram of another liquid level detection circuit provided by the present application.

[0068] Figure 7 is a schematic diagram of a beverage machine provided by the present application.

[0069] Figure 8 is a schematic diagram of a liquid level probe setting mode in a beverage machine provided by the present application. DETAILED DESCRIPTION

[0070] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0071] As described above, in existing applications, many beverage machines, such as coffee machines, milk tea preparation equipment, etc., are provided with liquid containers, such as steam boilers or hot water boilers, to store water or other prepared liquid. During beverage preparation, the liquid stored in the liquid container is directly used to complete beverage preparation according to the requirements of beverage preparation process, avoiding obtaining the corresponding liquid from other water sources or liquid containers far away from the beverage machine, thereby effectively improving the preparation efficiency of the beverage.

[0072] In actual application, as the beverage is prepared, the liquid pre-stored in the liquid container is consumed, which causes the liquid in the liquid container to gradually decrease. In order to ensure the normal operation of the beverage machine, the liquid storage in the liquid container needs to be detected at all times. Therefore, how to detect the liquid storage of the liquid container of the beverage machine and timely supplement the liquid container to ensure the normal operation of the beverage machine has become one of the technical problems to be solved by the person skilled in the art.

[0073] To solve the above problems, the liquid level detection circuit provided by the present application is applied to a beverage machine provided with a liquid container, and a liquid level sensing module is arranged in the accommodation space of the liquid container. In the case that the liquid level sensing module is in contact with the liquid, the liquid level detection circuit outputs a second direct current voltage representing that the liquid in the liquid container is sufficient. Correspondingly, in the case that the liquid sensing module is not in contact with the liquid, the liquid level detection circuit outputs a first direct current voltage representing that the liquid container needs to be supplemented with liquid. Therefore, whether the liquid container needs to be supplemented with liquid is indicated by outputting different direct current voltages, which provides a reference basis for timely supplementing the liquid container with liquid and helps to ensure the normal operation of the beverage machine.

[0074] Based on the above content, referring to Figure 1 The liquid level detection circuit provided by the present application comprises a bias voltage circuit 10, a pulse generation circuit 20 and a voltage conversion circuit 30, and the pulse generation circuit 20 is connected with the bias voltage circuit 10, the liquid level sensing module 40 and the voltage conversion circuit 30 respectively. The bias voltage circuit 10 is used to output a bias voltage. The pulse generation circuit 20 outputs a pulse voltage based on the bias voltage. The voltage conversion circuit 30 is used to convert the pulse voltage into a direct current voltage.

[0075] Specifically, based on the foregoing content, the liquid level detection circuit provided by the present application is applied to a beverage machine. The beverage machine comprises a liquid container 50 for storing liquid, and a liquid level sensing module 40 is arranged in the accommodation space of the liquid container 50. The liquid is stored in the accommodation space of the liquid container 50.

[0076] The liquid container 50 can be used to store water required for preparing beverages. Of course, it can also be used to store semi-finished liquid required for preparing beverages, such as lemonade or dairy products, etc. In actual application, the liquid container 50 can be used to store any liquid required for preparing beverages, which will not be described in detail here.

[0077] The liquid level sensing module 40 is fixedly disposed at a preset position within the containing space of the liquid container 50. As the amount of liquid stored in the liquid container 50 changes, the liquid level sensing module 40 may come into contact with the liquid or may become detached from it. As an optional implementation, the liquid level sensing module 40 can be implemented using a liquid level probe. In practical applications, one liquid level probe or a pair of liquid level probes can be selected. The selection of the liquid level probe and the configuration between the liquid level probe and the liquid container will be discussed in detail in subsequent embodiments and will not be elaborated here.

[0078] Combination Figure 1 As shown, the output terminal of the bias voltage circuit 10 is connected to the input terminal of the pulse generation circuit 20, and the bias voltage circuit 10 provides a bias voltage to the pulse generation circuit 20. The output terminal of the pulse generation circuit 20 is connected to the input terminals of the voltage conversion circuit 30 and the liquid level sensing module 40, respectively, and the pulse generation circuit 20 outputs a pulse voltage based on the bias voltage provided by the bias voltage circuit 10. The voltage conversion circuit 30 converts the obtained pulse voltage into a DC voltage, which is then output through the (…). Figure 1 (Shown as Out1) Output, further, the output terminal of the voltage conversion circuit 30 also serves as the output terminal of the liquid level detection circuit, providing the converted DC voltage to the subsequent circuit or the host computer.

[0079] Combination Figure 1 As shown, the liquid level sensing module 40 and the container wall of the liquid container 50 can be regarded as the two electrodes of a capacitor. Whether the liquid in the liquid container 50 is in contact with the liquid level sensing module 40 can significantly change the conductivity between the two. Specifically, when the liquid level sensing module 40 is not in contact with the liquid, i.e., the liquid level in the liquid container 50 is lower than the liquid level sensing module 40, the branch containing the liquid level sensing module 40 can be considered an open circuit due to the good insulating properties of air. This has no effect on the process of the pulse generation circuit 20 outputting pulse voltage. The pulse voltage output by the pulse generation circuit 20 is entirely output to the voltage conversion circuit 30, which outputs the first DC voltage in this case. Correspondingly, when the liquid level sensing module 40 is in contact with the liquid, i.e., the liquid level in the liquid container 50 is not lower than the liquid level sensing module 40, the dielectric constant of the equivalent capacitor formed by the liquid level sensing module 40 and the container wall of the liquid container 50 increases due to the good conductivity of the liquid. The capacitance of the equivalent capacitor increases accordingly, and the equivalent capacitor stores some electrical energy, i.e., absorbs part of the electrical energy of the pulse voltage output by the pulse generation circuit 20. The voltage conversion circuit 30 converts the voltage in this case to obtain the second DC voltage. It can be understood that the amplitude of the second DC voltage will be less than the amplitude of the first DC voltage.

[0080] Based on the foregoing, it can be seen that the first DC voltage is output when the liquid level sensing module 40 is not in contact with the liquid, and therefore the first DC voltage can be used to indicate that the liquid container 50 needs to be replenished with liquid. Correspondingly, the second DC voltage is output when the liquid level sensing module 40 is in contact with the liquid, and therefore the second DC voltage can be used to indicate that the liquid container 50 has sufficient liquid. The liquid level detection circuit outputs the first DC voltage to indicate that the liquid container 50 needs to be replenished with liquid, and outputs the second DC voltage to indicate that the liquid container 50 needs to stop being replenished with liquid. The liquid level detection circuit can indicate whether the liquid container 50 needs to be replenished with liquid by outputting the first DC voltage or the second DC voltage.

[0081] In summary, the liquid level detection circuit provided in the present application uses the conductivity of the liquid to convert part of the electrical energy of the pulse voltage to obtain the second DC voltage indicating that the liquid container 50 has sufficient liquid when the liquid level sensing module 40 is in contact with the liquid. Correspondingly, when the liquid level sensing module 40 is not in contact with the liquid, the branch in which the liquid level sensing module 40 is located is equivalent to an open circuit, and the voltage conversion circuit 30 converts to obtain the first DC voltage, which can be used to indicate that the liquid container 50 needs to be replenished with liquid. Based on this, the liquid level detection circuit provided in the present application can realize liquid level detection of the liquid container 50 of the beverage machine, and can indicate whether the liquid container 50 needs to be replenished with liquid by outputting different DC voltages, thereby providing a reference for timely replenishing the liquid container 50, and helping to ensure normal operation of the beverage machine.

[0082] Further, based on the output process of the first DC voltage and the second DC voltage, the output timing of the two is related to the setting position of the liquid level sensing module 40 in the liquid container (mainly the vertical distance between the liquid level sensing module 40 and the bottom of the liquid container 50). Therefore, by adjusting the position of the liquid level sensing module 40 in the liquid container 50, the timing of outputting the first DC voltage and the second DC voltage can be adjusted, thereby meeting the detection needs of different liquid levels and having a wide range of applications.

[0083] It can be understood that, Figure 1 In the liquid level detection circuit provided in the illustrated embodiment, the voltage amplitude of the first DC voltage output by the voltage conversion circuit 30 based on the pulse voltage provided by the pulse generation circuit 20 is also determined, and the voltage amplitude of the second DC voltage output by the voltage conversion circuit 30 is related to the conductivity of the liquid contained in the liquid container 50. In one possible application scenario, even if the liquid level sensing module 40 is in contact with the liquid, due to the poor conductivity of the liquid, it can only absorb a small part of the electrical energy of the pulse voltage. In this case, the second DC voltage output by the voltage conversion circuit 30 may be smaller than the first DC voltage, and there is a possibility of misjudgment.

[0084] To solve the above problems, this application provides another liquid level detection circuit, see [link to relevant documentation]. Figure 2 As shown, in Figure 1 Based on the embodiment shown, the liquid level detection circuit provided in this embodiment also includes a pulse absorption circuit 60, which is connected between the pulse generation circuit 20 and the liquid level sensing module 40. When the liquid level sensing module 40 is in contact with the liquid, the pulse absorption circuit 60 is used to absorb the electrical energy of the pulse voltage output by the pulse generation circuit 20.

[0085] Specifically, the output terminal of the pulse generating circuit 20 is connected to the input terminal of the pulse absorption circuit 60, and the output terminal of the pulse absorption circuit 60 is connected to the liquid level sensing module 40. That is, the pulse absorption circuit 60 is connected between the pulse generating circuit 20 and the liquid level sensing module 40. The pulse absorption circuit 20 is used to absorb the electrical energy of the pulse voltage output by the pulse generating circuit 20 when the liquid level sensing module 40 comes into contact with the liquid.

[0086] Understandably, compared to Figure 1 In the illustrated embodiment, when the liquid level sensing module 40 is not in contact with the liquid, the branch containing the liquid level sensing module 40 is also in an open circuit state. Therefore, Figure 2 The voltage conversion circuit 30 in the illustrated embodiment provides a first DC voltage and Figure 1 The first DC voltage provided in the illustrated embodiment shows almost no difference in voltage amplitude. However, when the liquid level sensing module 40 is in contact with the liquid, due to... Figure 2 The illustrated embodiment adds a pulse absorption circuit 60. Even if the equivalent capacitance formed by the liquid level sensing module 40 and the container wall of the liquid container 50 can only absorb a small amount of electrical energy from the pulse voltage due to the poor conductivity of the liquid, the pulse absorption circuit 60 can further absorb the electrical energy from the pulse voltage, thereby ensuring... Figure 2 In the embodiment shown, the voltage conversion circuit 30 outputs a second DC voltage that is significantly different from the first DC voltage, i.e., the second DC voltage is significantly smaller than the first DC voltage. The pulse absorption circuit 60 can effectively avoid misjudgment and improve the reliability and accuracy of the liquid level detection circuit.

[0087] In summary, compared to the aforementioned Figure 1 The embodiment shown, Figure 2The liquid level detection circuit provided by the embodiment shown adds the pulse absorption circuit 60. When the liquid level sensing module 40 is in contact with the liquid in the liquid container 50, the pulse absorption circuit 60 cooperates with the equivalent capacitor formed by the liquid level sensing module 40 and the container wall of the liquid container 50 to absorb the electric energy of the pulse voltage. Under the premise that the pulse voltage is provided by the pulse generation circuit 20, the electric energy output to the voltage conversion circuit 30 can be effectively reduced, so as to ensure that the difference between the second direct current voltage and the first direct current voltage provided by the voltage conversion circuit 30 is obvious enough, effectively identify whether the liquid container 50 needs to be replenished, and improve the accuracy of the liquid level detection result.

[0088] The pulse absorption circuit 60 includes a capacitor C3, which cooperates with the liquid level sensing module 40 to form an equivalent capacitor. Figure 3 As shown, one end of the capacitor C3 is connected to the output end of the pulse generation circuit 20 as the input end of the pulse absorption circuit 60, and the other end of the capacitor C3 is connected to the liquid level sensing module 40 as the output end of the pulse absorption circuit 60. Based on the characteristics of the capacitor, the capacitor C3 can store a certain amount of electric energy and can transmit alternating electric energy. Therefore, after the liquid level sensing module 40 is in contact with the liquid, the capacitor C3 grounds the liquid level sensing module 40, the liquid, and the liquid container 50 to form a closed loop, absorbs the electric energy provided by the pulse generation circuit 20, and further affects the amplitude of the direct current voltage finally output by the voltage conversion circuit 30.

[0089] It should be noted that the capacitor C3 can also play a role in isolation, that is, to prevent the abnormal voltage of the subsequent circuit from being fed back to the pulse generation circuit 20 and affecting the normal operation of the pulse generation circuit 20. Further, based on the foregoing, the present application provides a circuit topology of a liquid level detection circuit to exemplarily illustrate the composition of the liquid level detection circuit. The specific implementation of the liquid level detection circuit provided by the embodiment can be referred to Figure 3 as shown.

[0090] Specifically, the bias voltage circuit 10 includes a first voltage dividing resistor R1 and a second voltage dividing resistor R2. One end of the first voltage dividing resistor R1 is used to receive a reference voltage, the other end of the first voltage dividing resistor R1 is connected to one end of the second voltage dividing resistor R2, and the other end of the second voltage dividing resistor R2 is grounded. The connection end of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 is used to output a bias voltage to the pulse generation circuit 20.

[0091] One end of the first voltage dividing resistor R1, as the input end of the bias voltage circuit 10, receives a reference voltage (Vref). Figure 3For example, taking DC 3.3V as an example, the other end of the first voltage dividing resistor R1 is connected to one end of the second voltage dividing resistor R2, and the other end of the second voltage dividing resistor R2 is grounded, that is, the first voltage dividing resistor R1 and the second voltage dividing resistor R2 are connected in series to form a voltage dividing circuit. The connection end of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 serves as the output end of the bias voltage circuit 10 and outputs a bias voltage to the pulse generation circuit 20. For example, in the case where the reference voltage is 3.3V and the resistance values of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 are the same, a bias voltage of 1.65V can be provided to the pulse generation circuit 20 through voltage division. According to the voltage division principle of the voltage dividing circuit, the bias voltage is equal to the product of the voltage division ratio of the voltage dividing circuit and the reference voltage. By changing the resistance values of the first voltage dividing resistor R1 and the second voltage dividing resistor R2, the voltage division ratio of the voltage dividing circuit can be changed, thereby changing the specific output value of the bias voltage. In actual application, the first voltage dividing resistor R1 and the second voltage dividing resistor R2 can be selected according to the reference voltage and the specific size of the required bias voltage. The specific selection of the first voltage dividing resistor R1 and the second voltage dividing resistor R2 is not limited in the present application.

[0092] As for the reference voltage, it can be obtained in various ways in actual application. In an optional embodiment, a separate power supply can be provided for the liquid level detection circuit in the beverage machine, and the reference voltage is provided by the power supply. In another optional embodiment, the beverage machine is provided with a power supply network, which uniformly provides operating voltage for each component inside the beverage machine. In this case, the input end of the bias voltage circuit 10 can be connected to the power supply network, and the operating voltage provided by the power supply network is used as the reference voltage. Of course, the reference voltage can also be provided in other ways, and the specific provision method of the reference voltage is not limited in the present application.

[0093] The pulse generation circuit 20 includes a first comparator U1, a positive feedback resistor R3, a negative feedback resistor R4, and an energy storage capacitor C1. The positive feedback resistor R3 is connected between the positive input end of the first comparator U1 and the output end of the first comparator U1. The negative feedback resistor R4 is connected between the negative input end of the first comparator U1 and the output end of the first comparator U1. One end of the energy storage capacitor C1 is connected to the negative input end of the first comparator U1, and the other end of the energy storage capacitor C1 is grounded. The positive input end of the first comparator U1 is also used to receive the bias voltage output by the bias voltage circuit 10. The output end of the first comparator U1 is also used to output a pulse voltage.

[0094] In combination with Figure 3As shown, one end of the positive feedback resistor R3 is connected to the positive input terminal of the first comparator U1, and the other end of the positive feedback resistor R3 is connected to the output terminal of the first comparator U1, i.e. the positive feedback resistor R3 is connected between the positive input terminal of the first comparator U1 and the output terminal of the first comparator U1. One end of the negative feedback resistor R4 is connected to the negative input terminal of the first comparator U1, and the other end of the negative feedback resistor R4 is connected to the output terminal of the first comparator U1, i.e. the negative feedback resistor R4 is connected between the negative input terminal of the first comparator U1 and the output terminal of the first comparator U1. One end of the energy storage capacitor C1 is connected to the negative input terminal of the first comparator U1, and the other end of the energy storage capacitor C1 is grounded. The positive input terminal of the first comparator U1 is also connected to the output terminal of the bias voltage circuit 10 to receive the bias voltage provided by the bias voltage circuit 10.

[0095] In combination Figure 3 As shown, the positive feedback resistor R3 and the first comparator U1 form a positive feedback loop, and the output signal of the first comparator U1 is fed back to the positive input terminal of the first comparator U1 through the positive feedback resistor R3. At the same time, the output signal of the first comparator U1 is also fed back to the negative input terminal of the first comparator U1 through the negative feedback resistor R4. Before the energy storage capacitor C1 is fully charged, the voltage at the positive input terminal of the first comparator U1 is equal to the sum of the feedback voltage at the output terminal of the first comparator U1 and the bias voltage, and the voltage at the negative input terminal of the first comparator U1 is equal to the sum of the feedback voltage at the output terminal of the first comparator U1 and the capacitor voltage of the energy storage capacitor C1. Therefore, the voltage U+ at the positive input terminal of the first comparator U1 is greater than the voltage U- at the negative input terminal of the first comparator U1, and the output voltage of the first comparator U1 is approximately equal to the operating voltage of the first comparator U1, such as 3.3V.

[0096] At the same time, the negative feedback resistor R4 charges the energy storage capacitor C1. When the energy storage capacitor C1 is fully charged, the capacitor voltage is superimposed on the feedback voltage of the first comparator U1, which causes an overshoot, resulting in the voltage U- at the negative input terminal of the first comparator U1 being greater than the voltage U+ at the positive input terminal of the first comparator U1, and the output voltage of the first comparator U1 immediately becomes a minimum value (close to 0V). Since the output terminal of the first comparator U1 is approximately grounded at this time, the energy storage capacitor C1 will release the stored energy, and the discharging process stops after the output voltage of the first comparator U1 drops below the bias voltage. This cycle is repeated, i.e. a pulse voltage is provided to the subsequent circuit.

[0097] Further, as the energy storage capacitor C1 is continuously charged and discharged, it is equivalent to providing a triangular wave voltage to the inverting input terminal of the first comparator U1. Based on this, increasing the capacitance value of the energy storage capacitor C1 or reducing the resistance value of the negative feedback resistor R4 can adjust the frequency of the triangular wave voltage. In the case where the reference voltage is unchanged, that is, the frequency of the pulse voltage output by the pulse generation circuit 20 can be adjusted. Changing the resistance values of the first voltage dividing resistor R1 and the second voltage dividing resistor R2, that is, changing the amplitude of the reference voltage, can change the flip-over amplitude of the triangular wave voltage, thereby changing the duty cycle of the pulse voltage output by the pulse generation circuit 20. Based on this, in actual applications, the specific selection of each element in the bias voltage circuit 10 and the pulse generation circuit 20 can be adjusted according to the actual detection requirements, so as to change the frequency and duty cycle of the pulse voltage output by the pulse generation circuit 20, and meet the detection requirements in different scenarios. It should be noted that, according to practical application experience, the frequency and duty cycle of the pulse voltage should not be too small, otherwise the detection sensitivity of the liquid level detection circuit will be affected.

[0098] As an optional implementation, the pulse generation circuit 20 further comprises a first current limiting resistor R6. Figure 3 As shown in FIG. 4, one end of the first current limiting resistor R6 is connected to the output terminal of the first comparator U1, and the other end of the first current limiting resistor R6 serves as an output terminal of the pulse generation circuit 20 and is connected to a subsequent circuit. Figure 3 As shown in FIG. 4, the other end of the first current limiting resistor R6 is connected to the voltage conversion circuit 30 and the pulse absorption circuit 60, respectively. By the first current limiting resistor R6, the output current of the pulse generation circuit 20 can be prevented from being too large, thereby improving the safety of the circuit.

[0099] The voltage conversion circuit 30 comprises a unidirectional conduction circuit 310 and a filter circuit 320. The input terminal of the unidirectional conduction circuit 310 is connected to the pulse generation circuit 20, the output terminal of the unidirectional conduction circuit 310 is connected to the first terminal of the filter circuit 320, and the conduction direction of the unidirectional conduction circuit 310 is the same as the voltage drop direction of the filter circuit 320. The second terminal of the filter circuit 320 is grounded. The connection point of the unidirectional conduction circuit 310 and the filter circuit 320 is used to output a first direct current voltage or a second direct current voltage.

[0100] The conduction direction of the unidirectional conduction circuit 310 is the same as the voltage drop direction of the filter circuit 320. In the embodiment shown in FIG. 4, the unidirectional conduction circuit 310 is implemented by a diode D1. Figure 3 Figure 3 ​As shown, the anode of diode D1 is connected to the output of pulse generation circuit 20 as the input terminal of unidirectional conduction circuit 310, and the cathode of diode D1 is connected to the filter circuit 320 as the output terminal of unidirectional conduction circuit 310. In practical applications, the voltage drop generated by diode D1 when it is conducting is very small. Therefore, it will only cause a very small voltage attenuation to the pulse voltage output by pulse generation circuit 20, and the overall output of voltage conversion circuit 30 of diode D1 can be basically ignored.

[0101] The filter circuit 320 converts the pulse voltage output by the pulse generation circuit 20 into a DC voltage, while the unidirectional conduction circuit 310 prevents the electrical energy released by the filter circuit 320 from being output in reverse to the pulse generation circuit 20, thus affecting the normal operation of the entire circuit. Furthermore, in Figure 3 In the illustrated embodiment, the filter circuit 320 includes a filter resistor R8 and a filter capacitor C2. One end of the filter resistor R8 serves as the first terminal of the filter circuit 320, and the other end serves as the second terminal. The filter capacitor C2 is connected in parallel with the filter resistor R8. One end of the filter resistor R8, serving as the first terminal of the filter circuit 320, is connected to the output terminal of the unidirectional conduction circuit 310. The other end of the filter resistor R8, serving as the second terminal of the filter circuit 320, is directly grounded. The filter resistor R8 and the filter capacitor C2 connected in parallel form a low-pass filter circuit, converting the pulse voltage output by the pulse generation circuit 20 into a DC voltage.

[0102] It should be noted that, based on the configuration of the filter circuit 320, the unidirectional conduction circuit 310 is crucial for the normal operation of the voltage conversion circuit 30. This is because if the unidirectional conduction circuit 310 is removed, the energy storage process of the filter capacitor C2 will proceed normally and will not affect the operation of the preceding pulse generation circuit 20. However, during the discharge phase of the filter capacitor C2, the electrical energy released by the filter capacitor C2 may be output in reverse to the pulse generation circuit 20, causing the output of the first comparator U1 to become disordered and affecting the normal operation of the entire circuit.

[0103] It should also be noted that the amplitude of the DC voltage output by the voltage conversion circuit 30 is positively correlated with the amplitude of the pulse voltage, but the amplitudes of the two are not equal.

[0104] Based on the above connection relationship, the connection point between the unidirectional conduction circuit 310 and the filter circuit 320 serves as the output terminal of the voltage conversion circuit 30, used to output the aforementioned first DC voltage or second DC voltage.

[0105] As an optional implementation method, Figure 3 The voltage conversion circuit 30 provided in the illustrated embodiment also includes a second current-limiting resistor R7, combined with... Figure 3As shown, one end of the second current-limiting resistor R7 is connected to the output terminal of the pulse generating circuit 20 as the input terminal of the voltage conversion circuit 30, and the other end of the second current-limiting resistor R7 is connected to the input terminal of the unidirectional conducting circuit 310. The second current-limiting resistor R7 can limit the current flowing through the subsequent circuit, and at the same time, avoid the rapid increase of the current, thereby playing a certain buffering role and helping to improve the safety of the subsequent circuit.

[0106] As an optional embodiment, the liquid container 50 is made of conductive material and is grounded, and the liquid level sensing module 40 comprises a liquid level probe arranged at a predetermined height in the liquid container 50 and spaced apart from the liquid container 50, and the liquid level probe is connected to the liquid level detection circuit. Please refer to Figure 3 , Figure 8 The liquid level sensing module 40 in the embodiment shown comprises a liquid level probe arranged in the receiving space of the liquid container 50 and not in contact with the container wall of the liquid container 50. The liquid probe and the container wall can be regarded as two plates of a capacitor, and the substance filled between them will affect the capacitance of the equivalent capacitor. Based on the foregoing, the filling between the liquid level probe and the container wall can be liquid or air (in the case of coexistence of liquid and air, equivalent to air). It can be understood that in order to ensure that the liquid level probe can be effectively grounded when it is in contact with the liquid, thereby realizing the absorption of pulse voltage energy, the liquid container 50 should be made of conductive material, and the container wall of the liquid container 50 is grounded.

[0107] In another optional embodiment, the liquid level sensing module 40 comprises two spaced-apart liquid level probes arranged at a predetermined height in the liquid container 50, one of the two liquid level probes is connected to the liquid level detection circuit, and the other is grounded. Please refer to Figure 3 The liquid level sensing module 40 can also comprise two liquid level probes arranged at a predetermined height in the liquid container 50. It can be understood that the two liquid level probes can be equivalent to two electrodes of a capacitor, one of the two liquid level probes is connected to the pulse absorption circuit 60, and the other is grounded. When the liquid in the liquid container 50 is in contact with the two liquid level probes, the equivalent capacitor presents a certain capacitance value, and when the liquid in the liquid container 50 is not in contact with the two liquid level probes, the equivalent capacitor presents another capacitance value. In this way, the working process of the pulse absorption circuit 60 can be changed. For details, please refer to the foregoing related content, which will not be described here. Since one of the liquid level probes is grounded, in this embodiment, the liquid container 50 can be made of non-conductive material. Of course, in the case that the liquid level probe connected to the pulse absorption circuit 60 is not in contact with the container wall, the liquid container 50 can also be made of conductive material.

[0108] It can be understood that when the liquid level in the liquid container 50 is high enough to be replenished with liquid, the liquid level probe is in contact with the liquid, and as the beverage preparation liquid is used, the liquid level decreases, and the liquid level probe is out of contact with the liquid.

[0109] The specific working process of the liquid level detection circuit provided by the embodiment will be introduced below. Figure 4 The specific working process of the liquid level detection circuit provided by the embodiment will be introduced below.

[0110] After the circuit is powered on, the bias voltage circuit 10 cooperates with the pulse generation circuit 20 to provide pulse voltages to the branches where the voltage conversion circuit 30 and the pulse absorption circuit 60 are located, respectively. The specific generation process of the pulse voltage has been described in the foregoing content, and will not be repeated here.

[0111] When the liquid in the liquid container 50 is less, and the liquid level probe is not in contact with the liquid, the pulse absorption circuit 60 is equivalent to an open circuit, and will not absorb the electric energy of the pulse voltage. The electric energy of the pulse voltage is all input to the voltage conversion circuit 30, and the voltage conversion circuit 30 outputs a first direct current voltage with a larger amplitude to indicate that the liquid container 50 needs to be replenished with liquid.

[0112] When the liquid in the liquid container 50 is more, and the liquid level probe is in contact with the liquid, the liquid level probe is grounded through the liquid and the container wall of the liquid container 50. The equivalent capacitor formed by the pulse absorption circuit 60 and the container wall will simultaneously absorb the electric energy of the pulse voltage, and the pulse voltage will attenuate, showing a phenomenon of weakening the top peak. The original square wave voltage becomes an arch-shaped wave with a smaller amplitude. Then, the attenuated arch-shaped wave enters the voltage conversion circuit 30, and the voltage conversion circuit 30 generates a second direct current voltage to indicate that the liquid in the liquid container 50 is sufficient. Compared with the first direct current voltage, the second direct current voltage is smaller.

[0113] Based on the composition and working process of the above-mentioned liquid level detection circuit, compared with the liquid level detection circuit based on current change in the prior art, the liquid level detection circuit provided by the present application realizes liquid level detection based on voltage change. Since only two cases of whether in contact with the liquid need to be distinguished, the influence of electrode fouling of the liquid level probe on the detection result is minimal. The influence of electrode fouling on the detection accuracy can be effectively avoided. On the premise of ensuring the accuracy of the detection result, the liquid level detection circuit can be applied to more detection scenarios, has a wide application range, can be applied to the detection of any type of liquid, and can overcome the misjudgment caused by the difference in conductivity under the condition of different types of liquid. Moreover, the specific implementation of the circuit only needs basic elements such as resistors, capacitors and comparators, and the circuit structure is simple and the cost is low.

[0114] Further, the present application also provides another liquid level detection circuit, which is described below with reference to Figure 4As shown, on the basis of any of the preceding embodiments, the liquid level detection circuit provided by the embodiment further includes a control module 70 connected with the voltage conversion circuit 30, the control module 70 is configured to receive the direct current voltage output by the voltage conversion circuit 30, the control module 70 outputs a first control signal to control the liquid supplement device of the beverage machine to supplement liquid into the liquid container 50, the first control signal is generated according to the first direct current voltage; the control module 70 outputs a second control signal to control the liquid supplement device to stop supplementing liquid into the liquid container 50, the second control signal is generated according to the second direct current voltage.

[0115] In combination Figure 7 As shown, the input port of the control module 70 is connected with the output port of the voltage conversion circuit 30, and receives the first direct current voltage or the second direct current voltage provided by the voltage conversion circuit 30, the control module 70 outputs the first control signal in response to the obtained first direct current voltage, or outputs the second control signal in response to the obtained second direct current voltage, in actual application, for example, Figure 3 As shown, the beverage machine is provided with a liquid supplement device 80, such as a water pump 820 and a driving circuit 810 of the water pump, etc., the output port of the control module 70 is connected with the liquid supplement device 80, and can be connected with the driving circuit 810 of the water pump, based on this, the liquid supplement device 80 of the beverage machine is controlled to supplement liquid into the liquid container 50 through the first control signal, or the liquid supplement device 80 is controlled to stop supplementing liquid into the liquid container 50 through the second control signal.

[0116] In summary, compared with the liquid level detection circuit provided by each of the preceding embodiments, the liquid level detection circuit provided by the embodiment not only can detect whether the liquid container needs to supplement liquid, but also can control the liquid supplement process according to the detection result, to realize the automatic control of the liquid storage in the liquid container 50, which is of great significance to improve the working efficiency of the beverage machine.

[0117] In actual application, the control module 70 can have various implementation manners, in an optional implementation manner, the control module 70 includes a microcontroller 710, the voltage collection port of the microcontroller 710 is connected with the voltage conversion circuit 30; the microcontroller 710 is configured to output the first control signal in response to the first direct current voltage, or output the second control signal in response to the second direct current voltage. Please refer to Figure 3 , Figure 3 The control module 70 in the embodiment shown can be implemented by a microcontroller unit (MCU). For example, Figure 5 As shown in the liquid level detection circuit provided by the embodiment, the liquid level detection circuit provided by the embodiment can be as shown in Figure 6

[0118] ​The voltage sampling port of the MCU 710 is connected to the output end of the voltage conversion circuit 30 as an input port of the control module 70. The MCU 710 collects the direct current voltage output by the voltage conversion circuit 30, and outputs the first control signal when the obtained direct current voltage is the first direct current voltage, or outputs the second control signal when the obtained direct current voltage is the second direct current voltage. Then, the liquid supplementing device 80 of the beverage machine is controlled to supplement liquid into the liquid container 50 through the first control signal, or the liquid supplementing device 80 is controlled to stop supplementing liquid into the liquid container 50 through the second control signal. It should be noted that the specific process of outputting the corresponding control signal by the MCU 710 according to the obtained direct current voltage can be realized based on related technologies, for example, a preset corresponding relationship between the direct current voltage and the control signal can be established, and the MCU 710 can determine the control signal corresponding to the obtained direct current voltage according to the preset corresponding relationship after obtaining the direct current voltage. Of course, the control signal can also be output based on other ways, which will not be described here.

[0119] Based on the detection process of the liquid level detection circuit provided in the foregoing embodiments, it can be known that the specific values of the first direct current voltage and the second direct current voltage have no direct influence on the detection result of whether the liquid container 50 needs to be supplemented with liquid. As long as the obtained first direct current voltage is greater than the second direct current voltage, or as long as the difference between the first direct current voltage and the second direct current voltage is large enough, the current obtained direct current voltage can be effectively distinguished as the first direct current voltage or the second direct current voltage. Based on this, the corresponding voltage threshold value can be pre-configured in the MCU 710 based on the output of the voltage conversion circuit 30 in actual application. After obtaining the direct current voltage fed back by the voltage conversion circuit 30, the MCU 710 compares the obtained direct current voltage with the voltage threshold value. If the obtained direct current voltage is greater than the voltage threshold value, it is determined that the first direct current voltage is obtained. On the contrary, if the obtained direct current voltage is less than the voltage threshold value, it is determined that the second direct current voltage is obtained.

[0120] In actual application, assuming that the voltage threshold value is 1.8 V, if the obtained direct current voltage is 2 V, which is greater than 1.8 V, it is determined that the first direct current voltage is obtained, and the MCU 710 outputs the first control signal to control the liquid supplementing device 80 to supplement liquid into the liquid container 50. In an optional embodiment, the MCU 710 can also control the liquid supplementing time of the liquid supplementing device 80, for example, control the liquid supplementing device 80 to supplement liquid for 3 s, and stop supplementing liquid after the liquid supplementing time reaches 3 s. Then, it is determined whether the liquid supplementing needs to be continued according to the direct current voltage provided by the voltage conversion circuit 30. If the obtained direct current voltage is less than 1.8 V, for example, 1.4 V, it can be determined that the liquid in the liquid container 50 is sufficient, and the liquid supplementing can be stopped. In the subsequent use process, the liquid storage in the liquid container 50 gradually decreases. When the obtained direct current voltage is greater than 1.8 V, the liquid supplementing can be started again. In this way, the liquid storage in the liquid container 50 can meet the use requirement.

[0121] In another alternative implementation, the control module 70 can also be built based on hardware circuitry, see [link to relevant documentation]. Figure 6 As shown, in the liquid level detection circuit provided in this embodiment, the control module 70 includes a threshold voltage circuit 720 and a window comparison circuit 730. The window comparison circuit 730 is connected to the voltage conversion circuit 30, and the voltage conversion circuit 30 outputs a first DC voltage or a second DC voltage to the window comparison circuit 730. The threshold voltage circuit 720 is used to output a first threshold voltage to the window comparison circuit 730. The window comparison circuit 730 outputs a first control signal when the first DC voltage is greater than the first threshold voltage, and outputs a second control signal when the second DC voltage is less than the first threshold voltage. Specifically, the threshold voltage circuit 720 outputs the first threshold voltage, and the window comparison circuit 730 outputs the first control signal when the first DC voltage is greater than the first threshold voltage, and further, outputs the second control signal when the second DC voltage is less than the first threshold voltage.

[0122] Combination Figure 6 As shown, the threshold voltage circuit 720 includes a third voltage divider resistor R9, a fourth voltage divider resistor R10, and a fifth voltage divider resistor R11. These three resistors are connected in series to form a series branch. One end of the series branch receives a reference voltage, and the other end is grounded. The connection point between the fourth voltage divider resistor R10 and the fifth voltage divider resistor R11 is used to output the first threshold voltage to the window comparator circuit 730. One end of the third voltage divider resistor R9 serves as one end of the series branch, receiving the reference voltage, for example... Figure 6 The 3.3V shown is used as the reference voltage, and the other end of the fifth voltage divider resistor R11 is grounded as the other end of the series branch. For the specific implementation of the reference voltage, please refer to the relevant content in the aforementioned embodiments, which will not be repeated here.

[0123] It is understood that the third voltage-dividing resistor R9, the fourth voltage-dividing resistor R10, and the fifth voltage-dividing resistor R11, connected in series, form a voltage divider circuit. The connection point of any two adjacent voltage-dividing resistors can be used to output a divided voltage. This application uses each divided voltage as a threshold voltage. Specifically, the connection point of the fourth voltage-dividing resistor R10 and the fifth voltage-dividing resistor R11 is used to output the first threshold voltage. Taking a reference voltage of 3.3V as an example, after voltage division, the first threshold voltage of 1.2V can be obtained. Of course, by choosing different voltage division ratios, other threshold voltages can be obtained, which will not be detailed here.

[0124] The window comparison circuit 730 comprises a second comparator U2 and a third comparator U3. The positive input terminal of the second comparator U2 is configured to receive the second threshold voltage. The negative input terminal of the second comparator U2 is connected to the positive input terminal of the third comparator U3. The negative input terminal of the third comparator U3 is configured to receive the first threshold voltage. The output terminal of the second comparator U2 is connected to the output terminal of the third comparator U3, serving as the output terminal of the window comparison circuit 730. The connection point of the negative input terminal of the second comparator U2 and the positive input terminal of the third comparator U3 is connected to the voltage conversion circuit 30.

[0125] In combination Figure 6 As shown in the figure, the negative input terminal of the second comparator U2 is connected to the positive input terminal of the third comparator U3. The negative input terminal of the third comparator U3 is connected to the connection point of the fourth voltage dividing resistor R10 and the fifth voltage dividing resistor R11, receiving the first threshold voltage.

[0126] The output terminals of the second comparator U2 and the third comparator U3 are connected, serving as the output terminal of the window comparison circuit 730 (labeled as Out2), configured to output the aforementioned first control signal or the second control signal. The connection point of the negative input terminal of the second comparator U2 and the positive input terminal of the third comparator U3, serving as the input terminal of the window comparison circuit 730, is connected to the output terminal of the voltage conversion circuit 30. Figure 6 It is worth emphasizing that the output terminal of the second comparator U2 and the output terminal of the third comparator U3 are connected. In the case that both of them output high level, the window comparison circuit 730 outputs high level, i.e., the first control signal. In the case that at least one of them outputs low level, the window comparison circuit 730 outputs low level, i.e., the second control signal.

[0127] In combination Figure 6 As shown in the circuit topology, in the case that the direct current voltage output by the voltage conversion circuit 30 is greater than the first voltage threshold, the second comparator U2 and the third comparator U3 both output high level, i.e., the first control signal. It can be understood that the direct current voltage output by the voltage conversion circuit 30 at this time is the first direct current voltage.

[0128] In the case that the direct current voltage output by the voltage conversion circuit 30 is less than the first threshold voltage, the second comparator U2 outputs high level, and the third comparator U3 outputs low level. The window comparison circuit 730 outputs low level, i.e., the second control signal, indicating that the liquid in the liquid container 50 is sufficient. It can be understood that the direct current voltage output by the voltage conversion circuit 30 at this time is the second direct current voltage.

[0129] In practical application, it is assumed that the liquid level in the liquid container 50 is low when the beverage machine is powered on and fails to contact the liquid level probe, at this time, the direct current voltage output by the voltage conversion circuit 30 is large, greater than the first threshold voltage, the window comparison circuit 730 outputs the first control signal to control the liquid supplement device 80 to supplement liquid into the liquid container 50; correspondingly, after the preset time length of liquid supplement, the liquid level probe contacts the liquid, the direct current voltage output by the voltage conversion circuit 30 is less than the first threshold voltage, the window comparison circuit 730 outputs the second control signal to control the liquid supplement device 80 to stop supplementing liquid into the liquid container 50.

[0130] Further, the threshold voltage circuit 720 is also used for outputting the second threshold voltage to the window comparison circuit 730, and the second threshold voltage is greater than the first threshold voltage, specifically, the connection point of the third voltage dividing resistor R9 and the fourth voltage dividing resistor R10 is used for outputting the second threshold voltage to the window comparison circuit 730. The window comparison circuit 730 outputs the second control signal in the case that the first direct current voltage is greater than the second threshold voltage. In combination with Figure 7 As shown, the connection point of the third voltage dividing resistor R9 and the fourth voltage dividing resistor R10 is used for outputting the second threshold voltage, and based on the voltage dividing ratio of the voltage dividing circuit, it can be ensured that the second threshold voltage is greater than the first threshold voltage. Taking the reference voltage 3.3V as an example, after voltage division, the first threshold voltage 1.2V and the second threshold voltage 2V can be obtained, of course, other threshold voltages can also be obtained by selecting different voltage dividing ratios, which will not be described here in detail.

[0131] The positive input end of the second comparator U2 in the window comparison circuit 730 is connected with the connection point of the third voltage dividing resistor R9 and the fourth voltage dividing resistor R10 to receive the second threshold voltage. The window comparison circuit 730 will also output the second control signal in the case that the obtained first direct current voltage is greater than the second threshold voltage.

[0132] Specifically, in the case that the direct current voltage output by the voltage conversion circuit 30 is greater than the second voltage threshold, the second comparator U2 outputs low level, the third comparator U3 outputs high level, and the output end of the window comparison circuit 730 outputs low level, that is, the second control signal. It should be noted that, based on the foregoing content, it can be known that the second control signal represents that the liquid storage in the liquid container 50 is sufficient, and the liquid supplement to the liquid container 50 is stopped, that is, the liquid supplement device 80 of the beverage machine is stopped, based on this, the second control signal can also be used as a stop signal in a fault state, when the first direct current voltage is greater than the second threshold voltage, it can be determined that it is caused by the fault of other peripheral circuits of the beverage machine, in this case, the liquid level detection circuit provided in the present application can control the liquid supplement device 80 to stop, to a certain extent, avoid the further expansion of the fault range, and help to improve the operation reliability of the beverage machine.

[0133] In summary, the liquid level detection circuit provided in the embodiment saves the hardware resources of the microcontroller, effectively reduces the overall cost of the liquid level detection circuit, and avoids the risk of software control downtime. Compared with the control mode of the microcontroller, the control process is more reliable and has stronger anti-interference performance. In addition, through the size relationship between the first direct current voltage and the second threshold voltage, the running state of the peripheral circuit can also be detected. In the case of peripheral circuit failure, the liquid supplement device 80 can be controlled to stop running in time, which can avoid further expansion of the failure range to a certain extent and help improve the running reliability of the beverage machine.

[0134] Further, the application also provides a beverage machine, as shown in Figure 5 The beverage machine provided in the embodiment includes a liquid container 50, a liquid level sensing module 40, a liquid supplement device 80, and the liquid level detection circuit provided in any of the preceding embodiments (for example, the liquid level detection circuit provided in the embodiment shown in Figure 7 The embodiment is taken as an example.

[0135] The liquid supplement device 80 includes a water pump driving circuit 810 and a water pump 820, which are combined Figure 7 As shown in the figure, the control end of the water pump driving circuit 710 is connected to the output port of the MCU 710, the driving end of the water pump driving circuit 710 is connected to the water pump 820, and the water outlet of the water pump 820 is in communication with the water inlet of the liquid container 80.

[0136] The liquid level sensing module 40 is arranged in the containing space of the liquid container 50. The liquid level detection circuit is connected to the liquid level sensing module 40 and the liquid supplement device 80, respectively. The liquid level detection circuit controls the liquid supplement device 80 to supplement liquid into the liquid container 50 or controls the liquid supplement device 80 to stop supplementing liquid into the liquid container 50 in response to the contact condition of the liquid level sensing module 40 and the liquid in the liquid container. For the specific process of detecting the liquid level by the liquid level detection circuit and the specific process of controlling the liquid supplement device based on the liquid level detection result, reference can be made to the foregoing content, which will not be repeated here.

[0137] It should be noted that, in the Figure 8 embodiment, the liquid container 50 is made of conductive material and is grounded, and the liquid level sensing module 40 includes a liquid level probe arranged in the containing space of the liquid container and not in contact with the liquid container 50.

[0138] In another alternative embodiment, the liquid level sensing module 40 can also include two liquid level probes, as shown in ​ , i.e., a liquid level probe A and a liquid level probe B. The two liquid level probes are arranged at a predetermined height in the liquid container 50. One of the liquid level probes (i.e., the liquid level probe A) is connected to the liquid level detection circuit, and the other liquid level probe (i.e., the liquid level probe B) is grounded.

[0139] In practical applications, the beverage machine can be a coffee machine or a device for preparing other beverages, which are not listed one by one here.

[0140] Those skilled in the art will appreciate that the disclosure disclosed herein can have various modifications and improvements. For example, the various devices or components described above can be implemented by hardware, or by software, firmware, or a combination of some or all of the three.

[0141] In addition, although the present disclosure makes various references to certain units in the system according to the embodiments of the present disclosure, however, any number of different units can be used and run on the client and / or server. The units are only illustrative, and different aspects of the system and method can use different units.

[0142] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0143] The above is a description of the present disclosure and should not be considered as a limitation thereof. Although several exemplary embodiments of the present disclosure are described, those skilled in the art will readily understand that many modifications can be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure defined by the claims. It should be understood that the above is a description of the present disclosure and should not be considered as a limitation thereof. The disclosed embodiments are not intended to be limited to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. The present disclosure is defined by the claims and their equivalents.

Claims

1. A liquid level detection circuit for a beverage machine, the circuit comprising: The beverage machine comprises a liquid container, and a liquid level sensing module is arranged in a containing space of the liquid container, and the circuit comprises a bias voltage circuit, a pulse generation circuit and a voltage conversion circuit, wherein The pulse generation circuit is connected with the bias voltage circuit, the liquid level sensing module and the voltage conversion circuit respectively; The bias voltage circuit is used for outputting a bias voltage; The pulse generation circuit outputs a pulse voltage based on the bias voltage; The voltage conversion circuit is used for converting the pulse voltage into a direct current voltage; In the case that the liquid level sensing module is not in contact with the liquid in the liquid container, the voltage conversion circuit outputs a first direct current voltage, and the first direct current voltage represents that the liquid container needs to be replenished with liquid; In the case that the liquid level sensing module is in contact with the liquid in the liquid container, the voltage conversion circuit outputs a second direct current voltage, and the second direct current voltage represents that the liquid in the liquid container is sufficient, wherein the second direct current voltage is smaller than the first direct current voltage.

2. The liquid level detection circuit according to claim 1, characterized in that Further comprising: a pulse absorption circuit, wherein The pulse absorption circuit is connected between the pulse generation circuit and the liquid level sensing module; In the case that the liquid level sensing module is in contact with the liquid, the pulse absorption circuit is used for absorbing the electric energy of the pulse voltage output by the pulse generation circuit.

3. The liquid level detection circuit of claim 1, wherein The bias voltage circuit comprises a first voltage dividing resistor and a second voltage dividing resistor, wherein One end of the first voltage dividing resistor is used for receiving a reference voltage, the other end of the first voltage dividing resistor is connected with one end of the second voltage dividing resistor, and the other end of the second voltage dividing resistor is grounded; The connection point of the first voltage dividing resistor and the second voltage dividing resistor is used for outputting the bias voltage to the pulse generation circuit.

4. The liquid level detection circuit of claim 1, wherein The pulse generation circuit comprises a first comparator, a positive feedback resistor, a negative feedback resistor and an energy storage capacitor, wherein The positive feedback resistor is connected between the positive input end of the first comparator and the output end of the first comparator; The negative feedback resistor is connected between the negative input end of the first comparator and the output end of the first comparator; One end of the energy storage capacitor is connected with the negative input end of the first comparator, and the other end of the energy storage capacitor is grounded; The positive input end of the first comparator is also used for receiving the bias voltage; The output end of the first comparator is also used for outputting the pulse voltage.

5. The liquid level detection circuit of claim 1, wherein The voltage conversion circuit comprises a unidirectional conduction circuit and a filter circuit, wherein The input end of the unidirectional conduction circuit is connected with the pulse generation circuit, the output end of the unidirectional conduction circuit is connected with the first end of the filter circuit, and the conduction direction of the unidirectional conduction circuit is the same as the voltage drop direction of the filter circuit; The second end of the filter circuit is grounded; The connection point of the unidirectional conduction circuit and the filter circuit is used for outputting the first direct current voltage or the second direct current voltage.

6. The liquid level detection circuit according to claim 5, characterized in that The filter circuit comprises a filter resistor and a filter capacitor, wherein One end of the filter resistor is used as the first end of the filter circuit, and the other end of the filter resistor is used as the second end of the filter circuit; The filter capacitor is connected with the filter resistor in parallel.

7. The liquid level detection circuit according to any one of claims 1 to 6, characterized in that, Further comprising: a control module connected with the voltage conversion circuit, the control module configured to receive the DC voltage output by the voltage conversion circuit, wherein the control module outputs a first control signal to control the liquid supplement device to supplement liquid into the liquid container, the first control signal being generated according to the first DC voltage; the control module outputs a second control signal to control the liquid supplement device to stop supplementing liquid into the liquid container, the second control signal being generated according to the second DC voltage.

8. The liquid level detection circuit according to claim 7, characterized in that the control module comprises a microcontroller, wherein a voltage collection port of the microcontroller is connected with the voltage conversion circuit; the microcontroller is configured to output the first control signal in response to the first DC voltage, or output the second control signal in response to the second DC voltage.

9. The liquid level detection circuit of claim 7, wherein, the control module comprises a threshold voltage circuit and a window comparison circuit, wherein the window comparison circuit is connected with the voltage conversion circuit, and the voltage conversion circuit outputs the first DC voltage or the second DC voltage to the window comparison circuit; the threshold voltage circuit is configured to output a first threshold voltage to the window comparison circuit; the window comparison circuit outputs the first control signal when the first DC voltage is greater than the first threshold voltage, and outputs the second control signal when the second DC voltage is less than the first threshold voltage.

10. The liquid level detection circuit of claim 9, wherein, the threshold voltage circuit is further configured to output a second threshold voltage to the window comparison circuit, and the second threshold voltage is greater than the first threshold voltage; the window comparison circuit outputs the second control signal when the first DC voltage is greater than the second threshold voltage.

11. The liquid level detection circuit according to claim 10, characterized in that the threshold voltage circuit comprises a third voltage dividing resistor, a fourth voltage dividing resistor and a fifth voltage dividing resistor, wherein the third voltage dividing resistor, the fourth voltage dividing resistor and the fifth voltage dividing resistor are connected in series to form a series branch; one end of the series branch is configured to receive a reference voltage, and the other end of the series branch is grounded; a connection point between the third voltage dividing resistor and the fourth voltage dividing resistor is configured to output the second threshold voltage to the window comparison circuit; a connection point between the fourth voltage dividing resistor and the fifth voltage dividing resistor is configured to output the first threshold voltage to the window comparison circuit.

12. The liquid level detection circuit of claim 10, wherein, the window comparison circuit comprises a second comparator and a third comparator, wherein a positive input terminal of the second comparator is configured to receive the second threshold voltage, and a negative input terminal of the second comparator is connected with a positive input terminal of the third comparator; a negative input terminal of the third comparator is configured to receive the first threshold voltage; an output terminal of the second comparator and an output terminal of the third comparator are connected, serving as an output terminal of the window comparison circuit; a connection point between the negative input terminal of the second comparator and the positive input terminal of the third comparator is connected with the voltage conversion circuit.

13. A drinks machine characterised in that, Further comprising: a liquid container, a liquid level sensing module, a liquid supplement device, and a liquid level detection circuit according to any one of claims 1 to 12, wherein The liquid level sensing module is arranged in the containing space of the liquid container; The liquid level detection circuit is connected with the liquid level sensing module and the liquid supplement device respectively; The liquid level detection circuit controls the liquid supplement device to supplement liquid into the liquid container or controls the liquid supplement device to stop supplementing liquid into the liquid container according to the contact state between the liquid level sensing module and the liquid in the liquid container.

14. The beverage maker according to claim 13, wherein: The liquid container is made of conductive material and is grounded, the liquid level sensing module comprises a liquid level probe arranged at a preset height in the liquid container and spaced from the liquid container, and the liquid level probe is connected with the liquid level detection circuit; or the liquid level sensing module comprises two liquid level probes arranged at a preset height in the liquid container and spaced from each other, one of the two liquid level probes is connected with the liquid level detection circuit, and the other is grounded. ​

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