Leakage detection circuit and water meter

Abstract

The utility model provides a leakage detection circuit and a water meter, and relates to the technical field of water meter application, the leakage detection circuit comprises a reference voltage circuit, a current detection and amplification circuit, a low-pass filter circuit, a single-chip microcomputer and an alarm module; the reference voltage circuit is connected with the current detection and amplification circuit and is used for outputting reference voltage; the current detection and amplification circuit is connected with the low-pass filter circuit and is used for amplifying the real-time leakage current, converting the real-time leakage current into real-time leakage voltage and comparing the real-time leakage voltage with reference voltage to obtain a comparison voltage value; wherein the comparison voltage value is used for representing a leakage detection result; the low-pass filter circuit is connected with the single-chip microcomputer and used for performing noise reduction and filtering operation on the comparison voltage value and sending the comparison voltage value to the single-chip microcomputer; the single chip microcomputer is connected with the alarm module and is used for controlling the working state of the alarm module under the action of the comparison voltage value after the noise reduction and filtering operation; and the leakage condition is detected and alarmed, so that the technical problem that the leakage affects the water meter reading is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of water meter application, in particular to a leakage detection circuit and a water meter. Background Art

[0002] During water meter operation, flow oscillation significantly impacts flow measurement accuracy. This oscillation is primarily caused by factors such as flow velocity variations, pressure fluctuations, and pipe elbows and pipe materials. This oscillation leads to unstable water flow, disrupting the proper operation of the turbine and gears within the meter. In particular, in the event of leakage, the measurement waveform often exhibits abnormalities and noise. In these cases, the meter's flow measurement error is often significant, potentially causing users to miscalculate water flow. Utility Model Content

[0003] The utility model aims to provide a leakage detection circuit and a water meter, which can detect and alarm leakage and alleviate the technical problem that leakage affects the water meter reading.

[0004] In a first aspect, an embodiment of the present utility model provides a leakage detection circuit, comprising a reference voltage circuit, a current detection and amplification circuit, a low-pass filter circuit, a single-chip microcomputer, and an alarm module;

[0005] The reference voltage circuit is connected to the current detection and amplification circuit and is used to output a reference voltage;

[0006] The current detection and amplification circuit is connected to the low-pass filter circuit, and is used to amplify the real-time leakage current and convert it into a real-time leakage voltage, and compare the real-time leakage voltage with the reference voltage to obtain a comparative voltage value; wherein the comparative voltage value is used to represent the leakage detection result;

[0007] The low-pass filter circuit is connected to the single-chip microcomputer and is used to perform noise reduction filtering on the comparison voltage value and send it to the single-chip microcomputer;

[0008] The single chip microcomputer is connected to the alarm module and is used to control the working state of the alarm module under the action of the comparison voltage value after the noise reduction filtering operation.

[0009] In combination with the first aspect, an embodiment of the present utility model provides a first possible implementation of the first aspect, wherein the first aspect further includes a feedback control circuit connected to the reference voltage circuit and the current detection and amplification circuit respectively;

[0010] The feedback control circuit is used to control the reference voltage circuit to adjust the reference voltage under the action of the comparison voltage value.

[0011] In combination with the first aspect, the embodiment of the present utility model provides a second possible implementation of the first aspect, wherein the feedback control circuit includes a resistor R11, a resistor R22, a resistor R33, a resistor R45, a capacitor C5, a capacitor C6, a capacitor C7 and a field effect transistor Q7;

[0012] One end of the resistor R11 is connected to the comparison voltage value output by the current detection and amplification circuit, the other end of the resistor R11 is connected to one end of the resistor R22 and one end of the resistor R33 respectively, the other end of the resistor R22 is connected to the source of the field effect transistor Q7, one end of the capacitor C6, one end of the capacitor C7, and the reference voltage circuit respectively, and the other end of the resistor R33 is connected to one end of the resistor R45 and one end of the capacitor C5 respectively;

[0013] The other end of the capacitor C5 is respectively connected to the other end of the capacitor C6, the other end of the capacitor C7, the drain of the field effect transistor Q7, and the other end of the capacitor C7, and is grounded;

[0014] The other end of the resistor R45 is connected to the drain of the field effect transistor Q7.

[0015] In combination with the first aspect, an embodiment of the present utility model provides a third possible implementation of the first aspect, wherein, when the comparison voltage value is greater than a preset voltage threshold, the feedback control circuit controls the field effect transistor Q7 to reach a preset conduction depth, and controls the reference voltage circuit to reduce the reference voltage;

[0016] The feedback control circuit turns off or turns on the field effect transistor Q7 when the comparison voltage value is less than a preset voltage threshold, and controls the reference voltage circuit to increase the reference voltage.

[0017] In combination with the first aspect, the embodiment of the present utility model provides a fourth possible implementation of the first aspect, wherein the reference voltage circuit includes a power chip U10, a capacitor C42, a capacitor C43, a capacitor C44 and a capacitor C45;

[0018] The reference voltage circuit includes an IN pin of the power chip U10 connected to one end of the capacitor C42 and 3V, and the other end of the capacitor C42 is grounded;

[0019] The reference voltage circuit includes an OUT pin of the power chip U10, which is respectively connected to one end of the capacitor C43 and the feedback control circuit, and outputs the reference voltage under the action of the feedback control circuit, and the other end of the capacitor C43 is grounded;

[0020] The reference voltage circuit includes a GND pin of the power chip U10 being grounded;

[0021] One end of the capacitor C44 is connected to 3V, and the other end of the capacitor C44 is grounded;

[0022] One end of the capacitor C45 is connected to 3V, and the other end of the capacitor C45 is grounded.

[0023] In combination with the first aspect, the embodiment of the present utility model provides a fifth possible implementation of the first aspect, wherein the current detection and amplification circuit includes a leakage collector J2, a resistor R44, a resistor R47, a resistor R48, a resistor R49, a resistor R43, a resistor R51, a resistor R52, a capacitor C55, a capacitor C51, a capacitor C48, an amplifier U11B and a comparator U11C;

[0024] The current detection and amplification circuit includes a pin 1 of the leakage collector J2 connected to one end of the resistor R48, and the other end of the resistor R48 is connected to one end of the capacitor C55, one end of the resistor R43, and the negative input end of the amplifier U11B;

[0025] The current detection and amplification circuit includes a pin 2 of the leakage collector J2 connected to one end of the resistor R49, and the other end of the resistor R49 is connected to one end of the capacitor C51, one end of the resistor R51, and the positive input end of the amplifier U11B;

[0026] The current detection and amplification circuit includes a leakage collector J2 with pin 3 grounded;

[0027] The other end of the capacitor C55 is connected to the other end of the resistor R43, the output end of the amplifier U11B, and one end of the capacitor C48. The other end of the capacitor C48 is connected to one end of the resistor R47. The other end of the resistor R47 is connected to one end of the resistor R44 and the negative input end of the comparator U11C. The other end of the resistor R44 is connected to the output end of the comparator U11C.

[0028] The other end of the capacitor C51 is connected to the other end of the resistor R51, the reference voltage, and one end of the resistor R52 respectively. The other end of the resistor R52 is connected to the positive input end of the comparator U11C.

[0029] In combination with the first aspect, the embodiment of the present utility model provides a sixth possible implementation of the first aspect, wherein the low-pass filter circuit includes a resistor R53, a resistor R54, a resistor R50, a capacitor C49, a capacitor C47, a capacitor C50 and an amplifier U11D;

[0030] One end of the capacitor C49 is connected to the comparison voltage value output by the current detection and amplification circuit, and the other end of the capacitor C49 is connected to one end of the resistor R53. The other end of the resistor R53 is respectively connected to one end of the capacitor C47, one end of the resistor R54, and the negative input terminal of the amplifier U11D;

[0031] The other end of the capacitor C47 is connected to the other end of the resistor R54, the output end of the amplifier U11D, and one end of the resistor R50. The other end of the resistor R50 is connected to one end of the capacitor C50. The other end of the capacitor C50 is grounded.

[0032] The positive input terminal of the amplifier U11D is connected to the reference voltage.

[0033] In combination with the first aspect, an embodiment of the present utility model provides a seventh possible implementation of the first aspect, wherein the alarm module includes an alarm; the alarm performs a corresponding operation under the control signal of the single chip microcomputer.

[0034] In combination with the first aspect, an embodiment of the present utility model provides an eighth possible implementation of the first aspect, wherein the alarm module includes a host computer; the host computer is used to receive the comparison voltage value after the noise reduction filtering operation sent by the microcontroller.

[0035] In a second aspect, an embodiment of the present invention further provides a water meter, comprising a water meter body and the leakage detection circuit as described above.

[0036] The embodiment of the present utility model brings a leakage detection circuit and a water meter, which improves the stability and accuracy of signal detection by combining a reference voltage circuit, a current detection and amplification circuit and a low-pass filtering circuit; the reference voltage provided by the reference voltage circuit ensures that the detection circuit has an accurate voltage reference, the current detection and amplification circuit can detect the comparison voltage between the reference voltage and the real-time leakage voltage, and effectively enhances the amplitude of the comparison voltage value, and the low-pass filtering circuit eliminates the interference of high-frequency signals on the comparison voltage value, so that the single-chip microcomputer can obtain a more accurate leakage detection result based on the comparison voltage value after comparison, amplification and filtering, and control the alarm module to perform corresponding operations based on this to ensure the reliability of the water meter digital display using the detection circuit.

[0037] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0038] In order to make the above objects, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0040] Figure 1 A leakage detection circuit block diagram provided by the present application embodiment;

[0041] Figure 2 A reference voltage circuit diagram in a leakage detection circuit provided by the present application embodiment;

[0042] Figure 3 A current detection and amplification circuit diagram in a leakage detection circuit provided by the present application embodiment;

[0043] Figure 4 A low-pass filter circuit diagram in a leakage detection circuit provided by the present application embodiment;

[0044] Figure 5 A feedback control circuit diagram in a leakage detection circuit provided by the present application embodiment. DETAILED DESCRIPTION

[0045] In order to make the objects, technical solutions and advantages of the present application more clear, the technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are some embodiments of the present application, not all 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.

[0046] The current leakage will affect the water meter detection number, and the detection scheme of the leakage current is relatively lacking.

[0047] Based on this, the leakage detection circuit and the water meter provided by the present application embodiment can detect the leakage current in time and alarm, so as to improve the reliability of the water meter detection number.

[0048] The following will be described in detail by embodiments.

[0049] Figure 1A leakage detection circuit block diagram provided in an embodiment of the present utility model.

[0050] Reference Figure 1 ,The leakage detection circuit includes a reference voltage circuit, a current detection and amplification circuit, a low-pass filter circuit, a single-chip microcomputer and an alarm module;

[0051] A reference voltage circuit is connected to the current detection and amplification circuit and is used to output a reference voltage;

[0052] The current detection and amplification circuit is connected to the low-pass filter circuit, and is used to amplify the real-time leakage current and convert it into a real-time leakage voltage, and compare the real-time leakage voltage with a reference voltage to obtain a comparative voltage value; wherein the comparative voltage value is used to represent the leakage detection result;

[0053] A low-pass filter circuit is connected to the single-chip microcomputer and is used for performing noise reduction and filtering operations on the comparison voltage value and sending it to the single-chip microcomputer;

[0054] The single chip microcomputer is connected to the alarm module and is used to control the working state of the alarm module under the action of the comparison voltage value after the noise reduction filter operation.

[0055] In a preferred embodiment of practical application, the stability and accuracy of signal detection are improved by combining a reference voltage circuit, a current detection and amplification circuit, and a low-pass filtering circuit; the reference voltage provided by the reference voltage circuit ensures that the detection circuit has an accurate voltage reference, the current detection and amplification circuit can detect the comparison voltage between the reference voltage and the real-time leakage voltage, and effectively enhance the amplitude of the comparison voltage value, and the low-pass filtering circuit eliminates the interference of high-frequency signals on the comparison voltage value, so that the single-chip microcomputer can obtain more accurate leakage detection results based on the comparison voltage value after comparison, amplification and filtering, and control the alarm module to perform corresponding operations based on this to ensure the reliability of the water level display using the detection circuit.

[0056] The reference voltage can be set to a preset value, such as 1.25V, which serves as the dividing line between a normal state (no leakage) and a state with leakage. The leakage detection circuit determines whether leakage exists by comparing the reference voltage with the voltage converted from the amplified real-time leakage current. In the normal state, the circuit current is balanced, no significant leakage current is generated, the voltage across the sampling resistor in the current detection and amplification circuit is essentially 0, and the real-time leakage voltage output after amplification is lower than the reference voltage. This indicates a normal state with no leakage. When leakage occurs, a portion of the current bypasses the normal circuit and flows to the ground, causing the voltage across the sampling resistor in the current detection and amplification circuit to increase. The increased real-time leakage current signal passes through the amplification circuit, outputting a higher real-time leakage voltage that exceeds the reference voltage, indicating a leakage state.

[0057] In order to obtain more accurate leakage detection results, the reference voltage can be dynamically set based on the leakage current (leakage current), that is, the current reference voltage changes based on the change of the leakage current; the application also includes a feedback control circuit, which is respectively connected to the reference voltage circuit and the current detection and amplification circuit;

[0058] The feedback control circuit is used to control the reference voltage circuit to adjust the reference voltage under the action of the comparison voltage value.

[0059] Among them, such as Figure 5 As shown, the feedback control circuit includes a resistor R11, a resistor R22, a resistor R33, a resistor R45, a capacitor C5, a capacitor C6, a capacitor C7 and a field effect transistor Q7;

[0060] One end of resistor R11 is connected to the comparison voltage value output by the current detection and amplification circuit, the other end of resistor R11 is connected to one end of resistor R22 and one end of resistor R33 respectively, the other end of resistor R22 is connected to the source of field effect transistor Q7, one end of capacitor C6, one end of capacitor C7, and a reference voltage circuit respectively, and the other end of resistor R33 is connected to one end of resistor R45 and one end of capacitor C5 respectively;

[0061] The other end of the capacitor C5 is respectively connected to the other end of the capacitor C6, the other end of the capacitor C7, the drain of the field effect transistor Q7, and the other end of the capacitor C7, and is grounded;

[0062] The other end of the resistor R45 is connected to the drain of the field effect transistor Q7.

[0063] The comparison voltage value is Verr, and the output end of the feedback control circuit is connected to the OUT pin of the REF312 chip of the reference voltage circuit. Capacitor C5 ensures the stability of the voltage divider signal, preventing noise interference and rapid malfunction. Capacitor C6 smoothes the reference voltage output by chip REF312, reducing dynamic noise. Capacitor C7 suppresses transient interference during the on- and off-states of the MOS transistor, protecting the smooth output of chip REF312. The feedback control circuit also includes a voltage divider network (signal conversion module) for converting Verr into an appropriate voltage range to drive the gate of the field-effect transistor (MOSFET), Q7. The voltage signal generated by the voltage divider network directly controls the conduction state of the MOSFET. The voltage divider network is composed of resistors R11, R22, R33, and R45. Resistors R11 and R22 form the input stage of the voltage divider network, reducing the current load of the input signal on the entire voltage divider network. Resistor R33 determines the distribution ratio of the gate control voltage in the voltage divider network, balancing the dynamic voltage divider signal. Resistor R45, together with resistor R33, determines the final gate voltage amplitude, providing a load path for the voltage divider network and reducing high-frequency signal jitter.

[0064] In practical applications, the field effect transistor Q7 dynamically adjusts its conduction degree according to the output signal of the voltage division network; based on the conduction depth affecting the shunt current output by the chip REF312, the reference voltage Vref output by the chip REF312 is finally dynamically adjusted.

[0065] The feedback control circuit controls the field effect transistor Q7 to reach the preset conduction depth and controls the reference voltage circuit to reduce the reference voltage when the comparison voltage value is greater than the preset voltage threshold.

[0066] The feedback control circuit turns off or turns on the field effect transistor Q7 and controls the reference voltage circuit to increase the reference voltage when the comparison voltage value is less than the preset voltage threshold.

[0067] It should be noted that the drain loss current passes through the current detection and amplification circuit to output the comparison voltage value Verr; under the action of the comparison voltage value Verr, when the field effect transistor Q7 is turned on, the shunt current output from the chip REF312 to the ground increases, resulting in a decrease in the reference voltage Vref; under the action of the comparison voltage value Verr, when the field effect transistor Q7 is turned off or partially turned on, the shunt current output from the chip REF312 to the ground decreases, thereby controlling the reference voltage Vref to increase.

[0068] When the comparison voltage value Verr not only exceeds the threshold voltage Vth of the field effect transistor Q7, but also needs to reach a certain overdrive voltage, so as to ensure that the field effect transistor Q7 enters the saturation region (fully turned on). Generally, the field effect transistor Q7 can be fully turned on at the critical voltage VGS≈Vth+2~3V;

[0069] When the comparison voltage value Verr is greater than the reference voltage Vref, the field effect transistor Q7 is triggered to start conduction, but the comparison voltage value Verr is lower than the value Vref+ΔV required for the field effect transistor Q7 to be fully turned on; here ΔV is the overdrive voltage difference for the field effect transistor Q7 to be fully turned on;

[0070] When the comparison voltage value Verr is slightly higher than the threshold voltage Vth of the field effect transistor Q7, the field effect transistor Q7 is in the linear region.

[0071] In some embodiments, as shown in Figure 2 The reference voltage circuit includes a power supply chip U10, a capacitor C42, a capacitor C43, a capacitor C44, and a capacitor C45.

[0072] The IN pin of the reference voltage circuit including the power supply chip U10 is connected to one end of the capacitor C42 and 3V, and the other end of the capacitor C42 is grounded.

[0073] The reference voltage circuit includes an OUT pin of the power chip U10 connected to one end of the capacitor C43 and the feedback control circuit, outputting a reference voltage under the action of the feedback control circuit, and the other end of the capacitor C43 is grounded;

[0074] The reference voltage circuit includes a GND pin of the power chip U10 being grounded;

[0075] One end of the capacitor C44 is connected to 3V, and the other end of the capacitor C44 is grounded;

[0076] One end of the capacitor C45 is connected to 3V, and the other end of the capacitor C45 is grounded.

[0077] The reference voltage circuit provides a stable voltage reference for the current detection and amplification circuit, directly connected to its input. The reference voltage is also a portion of the supply voltage, so a 1.25V reference voltage is used to account for the voltage difference between the supply voltage and leakage. If the reference voltage circuit can provide a stable 1.25V reference voltage for comparison with the real-time leakage voltage, a leakage current threshold of 3mA can be pre-set.

[0078] Figure 2 U10 in the left circuit is a precision voltage reference chip, model REF312, which is used to provide a highly stable 1.25V reference voltage Vref. Figure 2 The circuit on the right is powered by a 3V voltage power supply. The combination of two parallel capacitors C44 and C45 mainly enhances the filtering and stabilization effects, suppresses noise and stabilizes transient voltage of the reference voltage, and improves the overall stability and accuracy of the circuit.

[0079] Based on the above embodiments, Figure 3 As shown, the current detection and amplification circuit includes a leakage collector J2, a resistor R44, a resistor R47, a resistor R48, a resistor R49, a resistor R43, a resistor R51, a resistor R52, a capacitor C55, a capacitor C51, a capacitor C48, an amplifier U11B and a comparator U11C;

[0080] The current detection and amplification circuit includes connecting pin 1 of the leakage collector J2 to one end of the resistor R48, and the other end of the resistor R48 is connected to one end of the capacitor C55, one end of the resistor R43, and the negative input terminal of the amplifier U11B;

[0081] The current detection and amplification circuit includes connecting pin 2 of the leakage collector J2 to one end of the resistor R49, and the other end of the resistor R49 is connected to one end of the capacitor C51, one end of the resistor R51, and the positive input terminal of the amplifier U11B;

[0082] The current detection and amplification circuit includes pin 3 of the leakage collector J2 being grounded;

[0083] The other end of capacitor C55 is connected to the other end of resistor R43, the output end of amplifier U11B, and one end of capacitor C48. The other end of capacitor C48 is connected to one end of resistor R47. The other end of resistor R47 is connected to one end of resistor R44 and the negative input end of comparator U11C. The other end of resistor R44 is connected to the output end of comparator U11C.

[0084] The other end of the capacitor C51 is connected to the other end of the resistor R51, the reference voltage, and one end of the resistor R52. The other end of the resistor R52 is connected to the positive input end of the comparator U11C.

[0085] The leakage collector J2 can use vibration sensors, large-caliber ultrasonic flow detectors, and other devices to identify the minute current generated by leakage. This minute current enters the current detection and amplification circuit, generating a small voltage drop across sampling resistors R48 and R49. The sampling resistors work in conjunction with operational amplifier U11B. The minute voltage signal generated by the leakage current passing through the sampling resistor is amplified by operational amplifier U11B, converting the leakage current signal into a corresponding real-time leakage voltage signal. This real-time leakage voltage signal is coupled and bandpass filtered by resistor R47 and capacitor C48, passing the AC component to subsequent circuits while blocking DC bias to ensure the purity of the output signal. The signal is then input to comparator U11C, which compares the reference voltage Vref with the real-time leakage voltage to output the comparison voltage value Verr.

[0086] The positive terminal of amplifier U11B is connected to the reference voltage Vref via an RC network consisting of resistor R51 and capacitor C51, and then to comparator U11C. The current gradually flows from the first amplifier U11B to the second comparator U11C, creating a stable and enhanced detection signal. The negative terminal of amplifier U11B is connected in parallel with resistor R43 and capacitor C55, providing preliminary filtering.

[0087] Amplifier U11B uses reference voltage Vref as a reference point for current amplification. Second comparator U11C uses reference voltage Vref as a threshold to compare with the real-time leakage voltage output by amplifier U11B. The voltage difference between the two determines whether leakage current is occurring. If the real-time leakage voltage is no higher than the reference voltage, the circuit is considered normal, indicating no leakage. Resistor R44 is connected to the amplifier's output port and negative input, respectively, forming a negative feedback loop. Negative feedback ensures stable circuit operation and maintains an appropriate ratio between the output and input of comparator U11C. Its output is the comparison voltage value, Verr.

[0088] Based on the above embodiments, Figure 4 As shown, the low-pass filter circuit includes a resistor R53, a resistor R54, a resistor R50, a capacitor C49, a capacitor C47, a capacitor C50 and an amplifier U11D;

[0089] One end of capacitor C49 is connected to the comparison voltage value output by the current detection and amplification circuit, and the other end of capacitor C49 is connected to one end of resistor R53. The other end of resistor R53 is respectively connected to one end of capacitor C47, one end of resistor R54, and the negative input terminal of amplifier U11D;

[0090] The other end of the capacitor C47 is connected to the other end of the resistor R54, the output end of the amplifier U11D, and one end of the resistor R50. The other end of the resistor R50 is connected to one end of the capacitor C50. The other end of the capacitor C50 is grounded.

[0091] The positive input terminal of amplifier U11D is connected to the reference voltage.

[0092] This low-pass filter circuit is used to filter out noise and high-frequency interference in the signal, ensuring circuit stability. The comparison voltage value Verr, after passing through the current detection and amplification circuit, enters the low-pass filter circuit. This circuit further filters the high-frequency noise in the amplified comparison voltage value Verr, retaining the effective low-frequency signal and outputting a stable voltage signal representing the current change, ensuring sufficient signal strength for subsequent measurement and processing.

[0093] The RC network formed by series resistor R53 and capacitor C49 at the input acts as a high-frequency attenuator, providing preliminary high-frequency filtering of the input comparison voltage Verr. The RC network formed by parallel resistor R54 and capacitor C47 at both ends of the amplifier forms a feedback low-pass filter. This parallel RC network adjusts the amplifier's frequency response, gradually reducing the amplifier's gain at high frequencies while maintaining a high gain at low frequencies. The RC network formed by resistor R50 and capacitor C50 at the output of amplifier U11D provides final high-frequency attenuation of the amplified comparison voltage Verr.

[0094] Based on the aforementioned embodiment, the microcontroller can determine whether leakage is currently occurring based on the comparison voltage value after the noise reduction filter operation, and control the operating state of the alarm module based on the leakage detection result. The alarm module can be an alarm that performs corresponding operations under the control signal of the microcontroller. In the event of leakage, the alarm is activated by the control signal of the microcontroller.

[0095] Among them, the alarm module can also be a host computer; when a leakage occurs, the microcontroller can send the comparative voltage value after noise reduction and filtering operation to the host computer, so that the staff can know the current leakage phenomenon based on the comparative voltage value and repair it in time.

[0096] In practical applications, a reference voltage is initialized, and real-time leakage current is collected. This is then amplified by current detection and amplification circuits, thereby increasing the amplitude of the real-time leakage current. This voltage is then compared with the reference voltage to obtain a comparative voltage value. This comparative voltage value enters a low-pass filter circuit, filtering out high-frequency noise and environmental interference. If the filtered comparative voltage value is greater than the reference voltage, leakage is present and requires repair. If it is less than the reference voltage, monitoring continues. In water meter use, leakage can be determined by comparing the real-time leakage voltage with the reference voltage. Compared to traditional sensors, this sensor has improved sensitivity, interference resistance, detection accuracy, and power consumption.

[0097] In some embodiments, the present invention further provides a water meter, comprising a water meter body and the leakage detection circuit as described above.

[0098] The water meter provided in the embodiment of the present utility model has the same technical features as the leakage detection circuit provided in the above embodiment, and can therefore solve the same technical problems and achieve the same technical effects.

[0099] In the description of the embodiments of the present invention, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0100] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0101] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. There may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed may be through some communication interface, indirect coupling or communication connection of devices or units, which may be electrical, mechanical or other forms.

[0102] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0103] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0104] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention rather than to limit it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that any technician familiar with this technical field can still modify the technical solutions recorded in the aforementioned embodiments within the technical scope disclosed by the present invention, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered by the protection scope of the present invention.

Claims

1. A leakage detection circuit, characterized in that: Including reference voltage circuit, current detection and amplification circuit, low-pass filter circuit, single chip microcomputer and alarm module; The reference voltage circuit is connected to the current detection and amplification circuit and is used to output a reference voltage; The current detection and amplification circuit is connected to the low-pass filter circuit, and is used to amplify the real-time leakage current and convert it into a real-time leakage voltage, and compare the real-time leakage voltage with the reference voltage to obtain a comparative voltage value; wherein the comparative voltage value is used to represent the leakage detection result; The low-pass filter circuit is connected to the single-chip microcomputer and is used to perform noise reduction filtering on the comparison voltage value and send it to the single-chip microcomputer; The single chip microcomputer is connected to the alarm module and is used to control the working state of the alarm module under the action of the comparison voltage value after the noise reduction filtering operation.

2. The leakage detection circuit according to claim 1, wherein: It also includes a feedback control circuit, which is connected to the reference voltage circuit and the current detection and amplification circuit respectively; The feedback control circuit is used to control the reference voltage circuit to adjust the reference voltage under the action of the comparison voltage value.

3. The leakage detection circuit according to claim 2, wherein: The feedback control circuit includes a resistor R11, a resistor R22, a resistor R33, a resistor R45, a capacitor C5, a capacitor C6, a capacitor C7 and a field effect transistor Q7; One end of the resistor R11 is connected to the comparison voltage value output by the current detection and amplification circuit, the other end of the resistor R11 is connected to one end of the resistor R22 and one end of the resistor R33 respectively, the other end of the resistor R22 is connected to the source of the field effect transistor Q7, one end of the capacitor C6, one end of the capacitor C7, and the reference voltage circuit respectively, and the other end of the resistor R33 is connected to one end of the resistor R45 and one end of the capacitor C5 respectively; The other end of the capacitor C5 is respectively connected to the other end of the capacitor C6, the other end of the capacitor C7, the drain of the field effect transistor Q7, and the other end of the capacitor C7, and is grounded; The other end of the resistor R45 is connected to the drain of the field effect transistor Q7.

4. The leakage detection circuit according to claim 3, wherein: The feedback control circuit controls the field effect transistor Q7 to reach a preset conduction depth when the comparison voltage value is greater than a preset voltage threshold, and controls the reference voltage circuit to reduce the reference voltage; The feedback control circuit turns off or turns on the field effect transistor Q7 when the comparison voltage value is less than a preset voltage threshold, and controls the reference voltage circuit to increase the reference voltage.

5. The leakage detection circuit according to claim 2, wherein: The reference voltage circuit includes a power chip U10, a capacitor C42, a capacitor C43, a capacitor C44 and a capacitor C45; The reference voltage circuit includes an IN pin of the power chip U10 connected to one end of the capacitor C42 and 3V, and the other end of the capacitor C42 is grounded; The reference voltage circuit includes an OUT pin of the power chip U10, which is respectively connected to one end of the capacitor C43 and the feedback control circuit, and outputs the reference voltage under the action of the feedback control circuit, and the other end of the capacitor C43 is grounded; The reference voltage circuit includes a GND pin of the power chip U10 being grounded; One end of the capacitor C44 is connected to 3V, and the other end of the capacitor C44 is grounded; One end of the capacitor C45 is connected to 3V, and the other end of the capacitor C45 is grounded.

6. The leakage detection circuit according to claim 1, wherein: The current detection and amplification circuit includes a leakage collector J2, a resistor R44, a resistor R47, a resistor R48, a resistor R49, a resistor R43, a resistor R51, a resistor R52, a capacitor C55, a capacitor C51, a capacitor C48, an amplifier U11B and a comparator U11C; The current detection and amplification circuit includes a pin 1 of the leakage collector J2 connected to one end of the resistor R48, and the other end of the resistor R48 is connected to one end of the capacitor C55, one end of the resistor R43, and the negative input end of the amplifier U11B; The current detection and amplification circuit includes a pin 2 of the leakage collector J2 connected to one end of the resistor R49, and the other end of the resistor R49 is connected to one end of the capacitor C51, one end of the resistor R51, and the positive input end of the amplifier U11B; The current detection and amplification circuit includes a leakage collector J2 with pin 3 grounded; The other end of the capacitor C55 is connected to the other end of the resistor R43, the output end of the amplifier U11B, and one end of the capacitor C48. The other end of the capacitor C48 is connected to one end of the resistor R47. The other end of the resistor R47 is connected to one end of the resistor R44 and the negative input end of the comparator U11C. The other end of the resistor R44 is connected to the output end of the comparator U11C. The other end of the capacitor C51 is connected to the other end of the resistor R51, the reference voltage, and one end of the resistor R52 respectively. The other end of the resistor R52 is connected to the positive input end of the comparator U11C.

7. The leakage detection circuit according to claim 1, wherein: The low-pass filter circuit includes a resistor R53, a resistor R54, a resistor R50, a capacitor C49, a capacitor C47, a capacitor C50 and an amplifier U11D; One end of the capacitor C49 is connected to the comparison voltage value output by the current detection and amplification circuit, and the other end of the capacitor C49 is connected to one end of the resistor R53. The other end of the resistor R53 is respectively connected to one end of the capacitor C47, one end of the resistor R54, and the negative input terminal of the amplifier U11D; The other end of the capacitor C47 is connected to the other end of the resistor R54, the output end of the amplifier U11D, and one end of the resistor R50. The other end of the resistor R50 is connected to one end of the capacitor C50. The other end of the capacitor C50 is grounded. The positive input terminal of the amplifier U11D is connected to the reference voltage.

8. The leakage detection circuit according to claim 1, wherein: The alarm module includes an alarm; the alarm performs corresponding operations under the control signal of the single chip microcomputer.

9. The leakage detection circuit according to claim 1, wherein: The alarm module includes a host computer; the host computer is used to receive the comparison voltage value after the noise reduction filtering operation sent by the single chip computer.

10. A water meter, characterized in that: The water meter comprises a water meter body and also comprises a leakage detection circuit as claimed in any one of claims 1 to 9.

Images